Biphasic, Homogeneous, and Heterogeneous Hydrocarbon Conversion Reactions with Novel Aluminum Chloride Based Catalyst Systems

Biphasic, Homogeneous, and He e ogeneous Hyd oca bon Con e sion Reac ions wi h No el Aluminum Chlo ide Based Ca alys Sys ems DISSERTATION zu E langung des akademischen G ades eines Dok o s de Na u wissenscha en (D . e . na .) im Fach Chemie de Fakul ä ü Biologie, Chemie und Geowissenscha en de Uni e si ä Bay eu h o geleg on Dipl. Chemike Ma hias Dö e l gebo en in Naila Bay eu h, 2011 The ollowing wo k has been ca ied ou om May 2008 o Augus 2010 a he Chai o Ino ganic Chemis y II o he Uni e si ä Bay eu h unde he supe ision o P o . D . Helmu G. Al . This hesis ul ils he equi emen s o he doc o al deg ee o he acul y o Biology, Chemis y and Geological Sciences a he Uni e si y o Bay eu h. Thesis submi ed: 11.01.2011 Da e o Scien i ic Colloquium: 21.03.2011 Dean o he Facul y: P o . D . S ephan Clemens Examina ion Commi ee: Fi s Re e ee: P o . D . Helmu G. Al Second Re e ee: P o . D .-Ing. And eas Jess Thi d Re e ee: P o . D . Axel H. E. Mülle Chai man: P o . D . Ka lheinz Sei e Fü Ka ha ina Fü Ka ha inaFü Ka ha ina Fü Ka ha ina und Emil und Emilund Emil und Emil „We imme u , was e schon kann, bleib imme das, was e schon is .“ Hen y Fo d Abb e ia ions b b oad M n numbe a e age molecula weigh BMIM 1-bu yl-3-me hylimidazolium M w weigh a e age molecula weigh Bu bu yl MAO me hylaluminoxane °C deg ee celsius Me me hyl C qua e na y ca bon mg millig am(s) ( o 13 C NMR spec oscopy) MHz Megahe z Cy cyclohexyl min minu e(s) d double o day(s) ml millili e dd duplica ed double mmol millimol δ chemical shi (ppm) MP 2-me hylpen ene(s) DMB 2,3-dime hylbu ene(s) MPa megapascal dme dime hoxye hane MS mass spec ome y E e hyl N-MP N-me hylpy ole EROEI ene gy e u ned on ene gy in es ed NMR nuclea magne ic esonance g g am(s) no . de . no de e mined GC gas ch oma og aphy p pa a GC-MS gas ch oma og aphy- PDI polydispe si y index mass spec ome y ( = M w / M n ) h hou (s) PE polye hylene HDPE high densi y polye hylene Ph phenyl HEX n-hexene(s) R alkylchain ∆H m mel ing en halpy RON esea ch oc ane numbe HT-GPC high empe a u e RT oom empe a u e gel pe mea ion ch oma og aphy s single Hz He z SHOP Shell highe ole in p ocess IFP Ins i u F ançais du Pé ole SILP suppo ed ionic liquid phase J coupling cons an (Hz) iple o ime K Kel in T empe a u e L ligand T m mel ing poin LPG lique ied pe oleum gas TMA ime hylaluminum LLDPE linea low densi y polye hylene THF e ahyd o u ane LNG lique ied na u al gas w % weigh pe cen m me a X halide m mul iple Ξ e e ence equency M molecula weigh ( o NMR spec oscopy) ( o mass spec ome y) I Table o Con en s 1 Summa y .............................................................................................................. 1 2 In oduc ion ........................................................................................................ 11 2.1 Fossil Fuels and Oil Re ining ............................................................................... 11 2.2 Dime iza ion o Sho Chain Ole ins ..................................................................... 15 2.3 Coca alys s o T ansi ion Me al Ca alyzed Ole in Dime iza ion and Polyme iza ion Reac ions .................................................................................... 19 2.4 Re e ences .......................................................................................................... 22 3 O e iew o Thesis Resul s .............................................................................. 24 3.1 Hea y Me al wi h Hea y Impac : Ole in Dime iza ion Reac ions in T iphenylbismu h Bu e ed Chlo oalumina e Ionic Liquids ................................... 24 3.2 Facile Syn hesis o new Ca ionic T iphenylphosphine De i a i es and hei Use o P opene Dime iza ion Reac ions in Bu e ed Chlo oalumina e Ionic Liquids ................................................................................................................. 25 3.3 Nickel Ca alyzed P opene Dime iza ion Reac ions in BiPh3 Bu e ed Chlo oalumina e Ionic Liquids: High Pe o mance wi h Uncon en ional Ca ions ................................................................................................................ 25 3.4 Bu e ed Aluminum Chlo ide as Highly E icien Coca alys o Ole in Dime iza ion and Polyme iza ion Reac ions ........................................................ 26 3.5 Silica Suppo ed Coca alys s o Ole in Dime iza ion and Polyme iza ion Reac ions wi h Nickel Complexes ........................................................................ 27 3.6 Solubili y Beha iou o TiCl4, Z Cl4, and H Cl4 in Chlo oalumina e Ionic Liquids ................................................................................................................. 28 3.7 Oxida i e Coupling and Ca aly ic C acking o Alkanes in Lewis Acidic Chlo oalumina e Ionic Liquids Enhanced by Molecula Oxygen .......................... 28 3.8 Indi idual Con ibu ion o Join Publica ions ........................................................ 29 4 Hea y Me al wi h Hea y Impac : Ole in Dime iza ion Reac ions in T iphenylbismu h Bu e ed Chlo oalumina e Ionic Liquids ........................... 32 4.1 Main Tex ............................................................................................................. 32 4.2 Re e ences .......................................................................................................... 46 4.3 Suppo ing In o ma ion ........................................................................................ 48 5 Facile Syn hesis o new Ca ionic T iphenylphosphine De i a i es and hei Use o P opene Dime iza ion Reac ions in Bu e ed Chlo oalumina e Ionic Liquids ......................................................................... 52 5.1 In oduc ion .......................................................................................................... 53 5.2 Resul s and Discussion ....................................................................................... 55 II 5.3 Expe imen al Sec ion ........................................................................................... 66 5.4 Re e ences .......................................................................................................... 71 6 Nickel Ca alyzed P opene Dime iza ion Reac ions in BiPh3 Bu e ed Chlo oalumina e Ionic Liquids: High Pe o mance wi h Uncon en ional Ca ions ............................................................................................................... 73 6.1 In oduc ion .......................................................................................................... 74 6.2 Resul s and Discussion ....................................................................................... 76 6.3 Re e ences .......................................................................................................... 85 6.4 Suppo ing In o ma ion ........................................................................................ 88 7 Bu e ed Aluminum Chlo ide as Highly E icien Coca alys o Ole in Dime iza ion and Polyme iza ion Reac ions ................................................. 103 7.1 In oduc ion ........................................................................................................ 104 7.2 Resul s and Discussion ..................................................................................... 108 7.3 Expe imen al Sec ion ......................................................................................... 119 7.4 Re e ences ........................................................................................................ 122 8 Silica Suppo ed Coca alys s o Ole in Dime iza ion and Polyme iza ion Reac ions wi h Nickel Complexes .................................................................. 126 8.1 In oduc ion ........................................................................................................ 127 8.2 Resul s and Discussion ..................................................................................... 129 8.3 Expe imen al Sec ion ......................................................................................... 140 8.4 Re e ences ........................................................................................................ 143 9 Solubili y Beha iou o TiCl4, Z Cl4, and H Cl4 in Chlo oalumina e Ionic Liquids .............................................................................................................. 146 9.1 In oduc ion ........................................................................................................ 146 9.2 Resul s and Discussion ..................................................................................... 147 9.3 Expe imen al Sec ion ......................................................................................... 153 9.4 Re e ences ........................................................................................................ 154 10 Oxida i e Coupling and Ca aly ic C acking o Alkanes in Lewis Acidic Chlo oalumina e Ionic Liquids Enhanced by Molecula Oxygen ................ 157 10.1 Main Tex ........................................................................................................... 158 10.2 Re e ences ........................................................................................................ 161 11 Lis o Publica ions .......................................................................................... 163 12 Danksagungen ................................................................................................. 165 13 Decla a ion / E klä ung ................................................................................... 167 1 Summa y 1 1 Summa y The aim o his hesis was he de elopmen o no el coca alys s o nickel ca alyzed ole in dime iza ion and oligome iza ion eac ions. Fo his pu pose, cheap and ai s able Lewis acidic chlo oalumina e ionic liquids we e he s a ing poin o ou in es iga ions. Chlo oalumina e mel s a e immiscible wi h hyd oca bon phases, and hus, biphasic oligome iza ion eac ions allow a simple p oduc sepa a ion by decan a ion. Scheme 1: Fo ma ion o highly Lewis acidic [Al2Cl7]– anions in chlo oalumina e ionic liquids (a), hei dono -accep o in e ac ion wi h a bu e addi i e (b) and examples o success ully employed bu e s (c). Unmodi ied chlo oalumina e mel s con aining excess aluminum chlo ide p edominan ly ca alyze non selec i e, ca ionic ole in oligome iza ion eac ions. We ound ha he addi ion o iphenylamine, iphenylphosphine, o iphenylbismu h dono s e icien ly supp essed hese side eac ions o yield an ideal cheap and ai s able ionic liquid coca alys o common nickel complexes used o ole in dime iza ion o oligome iza ion eac ions (Scheme 1). Especially iphenylbismu h was able o bu e sligh ly acidic chlo oalumina e mel s as well as highly acidic composi ions. Fo nickel ca alyzed dime iza ion eac ions, we ound ha high bu e ing le els led o e y high selec i i ies o gi e dime s, while sys ems wi h lowe bu e con en s we e less selec i e bu 1 Summa y 2 ex emely ac i e. We p oposed a mechanism o Ni(II) ca alyzed selec i e ole in dime iza ion eac ions in alkylaluminum ee bu e ed chlo oalumina e mel s ha explained ou ca aly ic esul s. Fu he , he mel ing poin s o acidic chlo oalumina e mel s we e educed upon addi ion o BiPh3. Thus, oom empe a u e ionic liquid composi ions de i ed om 100 di e en o ganic halide sal s we e sc eened owa ds hei pe o mances in nickel ca alyzed selec i e p opene dime iza ion eac ions. An N- me hylpy olidine hyd ochlo ide based sys em main ained an excellen pe o mance e en a e se en ca aly ic cycles. Amines and BiPh3 used o such sys ems can be easily eco e ed by acid base ex ac ion. Subsequen ly, an op imized composi ion was success ully employed o dime ize e hene, p opene, 1-bu ene, and 1-hexene wi h high ac i i ies and selec i i ies. The p esence o s e ically demanding icyclohexylphosphine ligands in such sys ems led o he o ma ion o aluable b anched p oduc s. In o de o minimize leaching e ec s and o in es iga e he in e ac ions o a dono addi i e wi h he ionic liquid, a ca ionic pa a- ime hylammonium subs i u ed iphenyl- phosphine de i a i e was syn hesized. I s in e ac ion wi h he ionic liquid was moni o ed by means o 31P NMR spec oscopy (Scheme 2). While s ong P–Al in e ac ions in highly Lewis acidic composi ions esul ed in a b oad 31P NMR peak, a weak in e ac ion in neu al chlo oalumina e mel s was e lec ed in a sha p 31P NMR signal. Scheme 2: 31P NMR spec a o he in e ac ion o a ca ionic iphenylphosphine de i a- i e wi h a highly Lewis acidic (le ) and a neu al chlo oalumina e ionic liquid ( igh ). The concep o bu e ing highly Lewis acidic aluminum chlo ide cen e s was also ans e ed o bina y homogeneous sys ems. In combina ion wi h s oichiome ic amoun s o BiPh3 o N-me hylpy ole bu e , aluminum chlo ide eadily dissol ed in oluene and me hylene chlo ide o o m a highly e icien , cheap and ai s able 1 Summa y 3 coca alys o nickel ca alys p ecu so s. The ca aly ic esul s o hese bu e ed homogeneous coca alys s o ole in dime iza ion eac ions we e supe io o common py opho ic coca alys s used o he ac i a ion o nickel ca alys p ecu so s like E AlCl2 o E 2AlCl. Fu he mo e, he Lewis acidi ies o hese bina y homogeneous coca alys solu ions could be uned p ecisely by he choice o he sol en and he ype and amoun o bu e . Also, bu e addi ion e icien ly supp essed isome iza ion eac ions o he α- ole inic p oduc s. The in e ac ion o BiPh3 and N-me hylpy ole wi h AlCl3 was moni o ed by 27Al NMR spec oscopy (Scheme 3). S ong in e ac ions esul ed in b oad 27Al NMR signals and weakly Lewis acidic composi ions. In con as , coca alys sys ems wi h sha p 27Al NMR signals displayed high Lewis acidi ies. Scheme 3: 27Al NMR spec a o he dono -accep o in e ac ion o AlCl3 wi h iphenyl- bismu h (le ) and N-me hylpy ole ( igh ) in oluene. Fu he , he concep o bu e ing highly Lewis acidic aluminum species was ex ended o he e ogeneous sys ems (Scheme 4). The Lewis acidi ies o E AlCl2 o E 2AlCl modi ied silicas we e educed by he addi ion o BiPh3 o N-me hylpy ole bu e s. Bu e ed su ace modi ied silica coca alys s we e success ully employed o ac i a e nickel complexes o highly selec i e ole in dime iza ion eac ions. Also, su ace modi ied silica p o ed o be an ideal subs a e o he o ma ion o suppo ed ionic liquid phase (SILP) coca alys sys ems used in nickel ca alyzed ole in dime iza ion eac ions. 1 Summa y 10 we den. Die Polyme ausbeu e, das Molekula gewich und de Polydispe si ä sindex (PDI) des so e zeug en Polye hylens konn e du ch die Wahl des Lösungsmi els und de A und de Menge des zugegebenen Dono -Addi i s beein luss we den. Die Ole in- polyme isa ion mi Übe gangsme allkomplexen wu de bishe noch nich mi au AlCl3 basie enden Coka alysa o en besch ieben, wede in homogenen Sys emen noch in ionischen Flüssigkei en. Im Rahmen diese A bei wu den die e s en lu s abilen Aluminium-Coka alysa o sys- eme en wickel , die ausschließlich au AlCl3 basie en. Das Konzep de Dono - Akzep o -Wechselwi kung on s a k Lewis-sau en Aluminiumzen en mi schwach Lewis-basischen Dono -Molekülen konn e e olg eich au zweiphasige, homogene und he e ogene Sys eme angewende we den. Die e hal enen Mischungen e wiesen sich als e izien e Coka alysa o en ü die selek i e Dime isie ung und Polyme isa ion on Ole inen mi Nickelkomplexen. Du ch eine geeigne e Kombina ion des Lösungsmi els, de A und de Menge de Dono -Komponen e und de P ozesspa ame e können so maßgeschneide e Coka alysa o en ü eine Vielzahl on Ka alysa o o s u en e zeug we den. Die ge es e en Sys eme e wiesen sich bei de Ole in-Dime isie ung und Poly- me isa ion als äuße s ak i , langzei s abil und seh selek i . Du ch die Ve wendung on p eisgüns igen Komponen en und de Möglichkei , Dono -Addi i e ode Halogenidsalze zu ückzugewinnen, s ellen de a ige Sys eme iel e sp echende Al e na i en zu den s anda dmäßig e wende en Alkylaluminium-Coka alysa o en da . S a k Lewis-sau e Chlo oalumina schmelzen wu den wei e hin ü C acking- und Kupplungs eak ionen gesä ig e Alkane e wende . Beim C acking on n-Hep an in Gegenwa on molekula em Saue s o e höh e sich de Umsa z um meh als eine G ößeno dnung im Ve gleich zu Reak ionen un e Schu zgas. Dabei ielen o allem gas ö mige Alkane als Reak ionsp oduk e an. Dagegen üh e die gleiche Reak ion mi Cycloalkanen zu oxida i en Kupplungs eak ionen und dami zu Bildung on Dime en und T ime en. In Abwesenhei on O2 bilde en sich hingegen nu Skele isome e. Auße dem wu de es ges ell , dass sich bis zu äquimola e Mengen an Zi konium e a- chlo id und Ha nium e achlo id in neu alen Chlo oalumina schmelzen lös en. Die da aus esul ie enden e nä en Mischungen wa en s a k Lewis-saue . Die Ve - bindungen [Ti2Cl10][BMIM]2, [Z 2Cl10][BMIM]2 (BMIM = 1-bu yl-3-me hylimidazolium) und [H 2Cl9][PhNMe3] konn en so k is allisie und de en K is alls uk u en bes imm we den. 2 In oduc ion 11 2 In oduc ion 2.1 Fossil Fuels and Oil Re ining Al hough enewable ene gy sou ces a e jus beginning o a ac a en ion as se ious al e na i es, ossil uels will s ill be he main sou ce o ene gy in he nex decades. Wi h abou 35% in 2009, oil emains he leading uel ollowed by coal and na u al gas.[1] Besides i s use o gene a e hea o elec ici y, oil is an indispensable eeds ock o he p oduc ion o uel oils, gasoline, pe ochemicals, o plas ic ma e ials. Howe e , wi h inc easing demand and dec easing esou ces, oil p oduc ion becomes mo e and mo e ene gy-in ensi e. EROEI (ene gy e u ned on ene gy in es ed) is he amoun o usable ene gy gained om a ce ain ene gy esou ce di ided by he ene gy, which had o be expended. In he beginning, gian oil ields close o he su ace we e exploi ed, wi h negligible ene gy expendi u e. Due o an inc easing demand and he high p ice o oil, e en deepwa e d illing, a sands and oil shales ha e become economic oday. Howe e , he ne ene gy gain om hese esou ces is e y low compa ed o con en ional oil ields (Table 1). Table 1: Ene gy e u ned on ene gy in es ed (EROEI) a ios o some ossil uels.[2] Fossil Fuel EROEI Oil (1940 – 1960) 100 Coal 50 Oil (1970 – 1980) 25 Oil (global a e age) 19 Na u al Gas 10 Ta Sands 5.2 – 5.8 Oil Shale 1.5 – 4 2 In oduc ion 12 The e o e, i is necessa y o inc ease he e iciency o oil e ining p ocesses o maximize he yield o aluable p oduc s in combina ion wi h a minimum o was e p oduc ion and ene gy consump ion. Ce ainly, liquid uels like gasoline, diesel uel, o ke osene a e he mos aluable and use ul e ine y p oduc s since hey a e he p e equisi e o ou mobili y. Thus, he aim o a ypical oil e ine y is o maximize he yield o hese p oduc s, namely he hyd oca bon ac ion con aining be ween six and 20 ca bon a oms. Scheme 1 shows he p ocesses and yields o a ypical oil e ine y. Scheme 1: Simpli ied c ude oil p ocessing in e ine ies (a e aged c ude oil com- posi ions o an oil ca ying pipeline[3] and a e aged ou pu o US e ine ies in 2009[4]). 2 In oduc ion 13 Fi s , he c ude oil is dis illed o yield abou 50% o hyd oca bons wi hin he gasoline o diesel ange. Subsequen ly, he gases a e ans o med o highe hyd oca bons, while he hea y oils a e c acked o u he inc ease he gasoline and diesel yield. Ca aly ic c acking eac ions o high molecula weigh hyd oca bons a e usually pe - o med a high empe a u es and p oduce mo e aluable sa u a ed o unsa u a ed gases o gasoline. Thus, la ge amoun s o C1 o C4 alkanes and ole ins a e p oduced in e ine ies in addi ion o he gaseous ac ions dissol ed in c ude oil. Fu he , he exploi- a ion o a sands and oil shales equi es an ex ensi e use o ca aly ic c acking eac ions leading o he o ma ion o e en mo e ligh hyd oca bons. Unlike liquid uels, gases canno be s o ed o anspo ed easily, and consequen ly, hey ha e o be p ocessed di ec ly in o close o a e ine y. Scheme 2 shows he gases wi h one o ou ca bon a oms, which a e mainly p oduced in e ine ies, and hei po en ial uses. Al hough α-ole ins like e hene, p opene, o 1- bu ene a e used as monome s o he p oduc ion o poly-α-ole ins, he ma ke demand o uels is by a la ge han he size o he polyme ma ke . Consequen ly, oil e ining companies a e in e es ed in con e ing hese unsa u a ed gaseous ole ins o gasoline o diesel uels. Besides he alkyla ion o ole ins wi h isoalkanes ca alyzed by anhyd ous HF o H2SO4, selec i e dime iza ion and oligome iza ion eac ions o α-ole ins a e a p omising a emp o achie e ha goal. 2 In oduc ion 14 Scheme 2: Gaseous C1 – C4 hyd oca bons acc uing in oil e ine ies and hei possible uses. 2 In oduc ion 15 2.2 Dime iza ion o Sho Chain Ole ins The aim o his wo k was o con e he gaseous ole ins e hene, p opene, and bu enes o p oduc s con aining six o 20 ca bon a oms by selec i e dime iza ion and oligome i- za ion eac ions. Scheme 3 p o ides an o e iew o e he co esponding dime iza ion and oligome iza ion p oduc s and hei in ended uses. Ini ially, he wo k should be ocussed on selec i e p opene dime iza ion eac ions o gi e gasoline uels o o upg ade C3 eeds o yield b anched C6 ole ins o he HF ca alyzed alkyla ion wi h isobu ane. Fo example, selec i e p opene dime iza ion eac ions yield a mix u e o n- hexenes, 2-me hylpen enes, and 2,3-dime hylbu enes. The deg ee o b anching in nickel ca alyzed dime iza ion eac ions can be inc eased by he addi ion o s e ically demanding phosphine ligands like icyclohexylphosphine.[5] Fo gasoline, a high deg ee o b anching is desi able. The esea ch oc ane numbe (RON) is a measu e o he an i- knocking capaci y o a uel. Wi h a highe deg ee o b anching, he RON inc eases. Table 2 shows he RONs o ypical gasolines. Table 2: Resea ch oc ane numbe s (RONs) o common gasolines and addi i es.[6] Fuel RON US Gasoline 85 – 91 No malbenzin 91 Supe Benzin 95 Supe Plus Benzin 98 LPG[1] 103 – 111 LNG[2] 120 – 130 n-Hep ane 0 Isooc ane 100 Benzene 101 Toluene 110 Xylenes 117 [1] Lique ied pe oleum gas. [2] Lique ied na u al gas. 2 In oduc ion 16 Scheme 3: Possible dime iza ion and oligome iza ion p oduc s o e hene, p opene (RONs aken om he li e a u e[7]), and bu enes and hei in ended uses in e ine ies. 2 In oduc ion 17 Gasoline wi h a high RON is necessa y o maximize he engine e iciency o mode n ca s, which is p opo ional o he comp ession. Wi h highe comp ession le els, he endency o he uel o sel -igni e has o be educed. Thus, he demand o high oc ane gasoline is s eadily inc easing. Especially 2,3-dime hylbu enes display e y high esea ch oc ane numbe s a ound 100. Wi h a boiling poin o o e 50°C, hey can be used di ec ly o a e hyd ogena ion o boos oc ane a ings e en in summe . Fu he , i he con en o high oc ane a oma ics like benzene, oluene, o xylenes will be u he es ic ed by new egula ions, app op ia e al e na i es ha e o be ound. I he C6 ole ins p oduced by selec i e p opene dime iza ion eac ions a e alkyla ed wi h isobu ane in exis ing HF alkyla ion uni s, e en highe boiling, high oc ane sa u a ed C10 gasoline blends could be ob ained.[7d] In con as o p opene, oligome iza ion eac ions o e hene should yield linea ole ins. While linea α-ole ins a e used as co-monome s o he p oduc ion o LLDPE (linea low densi y polye hylene), C8 o C20 oligome s can be blended in o diesel uel. Fo diesel uels, a low deg ee o b anching is ad an ageous o a ou he sel -igni ion in he engine. Linea bu ene dime iza ion p oduc s can also be employed as diesel uel o eeds ock o he p oduc ion o plas icize s. I b anched p oduc s a e ob ained, hese can as well be used o blend in o gasoline. Ideally, a ca aly ic sys em would be able o isome ize and dime ize bu enes. The less eac i e, he modynamically mo e s able 2- bu enes a e isome ized “in si u” o gi e he mo e eac i e 1-bu ene in small amoun s, which is subsequen ly dime ized. In gene al, in e nal ole ins a e o lowe alue compa ed o α-ole ins, which makes he la e a mo e economic eeds ock o dime iza ion eac ions. The la ge numbe o indus ial p ocesses dealing wi h ole in dime iza ion and oligome iza ion mi o s he economic impo ance o hese eac ions (Table 3). Also, he capaci ies a e eno mous. Fo example, he combined e ine y capaci ies o all IFP (Ins i u F ançais du Pé ole) p ocesses lis ed in Table 3 exceeded 3.6 million ons pe yea in 2007.[8] The mos common ansi ion me als applied o his ype o ca alysis a e g oup IV me als, nickel, and ch omium. While some p ocesses selec i ely dime ize (Alphabu ol®, DIMERSOL®, DIFASOL®) o ime ize (Che onPhillips) α-ole ins, o he s yield a b oad dis ibu ion o oligome s. To some ex en , he maximum o he oligome dis ibu ion can be in luenced by a ying p ocess pa ame e s in unselec i e oligome iza ion p ocesses. Excep he Shell highe ole in p ocess (SHOP), all ca aly ic 2 In oduc ion 18 sys ems equi e he addi ion o a coca alys . Howe e , he SHOP is ope a ed unde mo e d as ic condi ions (80 – 140°C, 7 – 14 MPa) compa ed o nickel sys ems ac i a ed wi h aluminum based coca alys s.[9] Table 3: Indus ial ansi ion me al ca alyzed oligome iza ion p ocesses.[8a] P ocess Me al Coca alys P oduc s Alphabu ol® (IFP) Ti AlE 3 1-Bu ene DIMERSOL® (IFP) Ni E AlCl2 C6 / C8 DIFASOL® (IFP) Ni E AlCl2/AlCl3 (Ionic Liquid) C6 / C8 SHOP (Shell) Ni None (Biphasic) 1-Ole ins (C4 – C30) Che onPhillips C E xAlCl3–x 1-Hexene Idemi su Z E xAlCl3–x 1-Ole ins (C6 – C30) Alphaselec ® (IFP) Z E xAlCl3–x 1-Ole ins (C4 – C10) α-SabLin® (Sabic) Z E xAlCl3–x 1-Ole ins ( a iable) Linea -1® (UOP) Ni NaBH4 (Biphasic) 1-Ole ins (C4 – C10) Since nickel compounds a e ca aly ically e sa ile, cheap and usually insensi i e o ai o mois u e compa ed o g oup IV me als, we decided o ocus on nickel based dime i- za ion and oligome iza ion sys ems. The equi emen s o a ca aly ic dime iza ion sys em o be de eloped a e as ollows. Fi s , he sys em has o be cheap o compe e wi h es ablished echnologies. This equi es high ac i i ies, li e imes, con e sions and selec i i ies o bo h dime o ma ion and a speci ic deg ee o b anching. The ole ance owa ds impu i ies, mainly oxygen, sul u , amines, o aces o wa e , would u he educe he cos s o subs a e pu i ica ion. Also, he possibili y o ecycle o o egene a e spen ca alys s would be desi able. 2 In oduc ion 19 2.3 Coca alys s o T ansi ion Me al Ca alyzed Ole in Dime iza ion and Polyme iza ion Reac ions Nickel based ca alys s usually ha e o be ac i a ed by aluminum alkyls. Common coca alys s a e me hylaluminoxane (MAO) and i s de i a i es, e hylaluminum dichlo ide, die hylaluminum chlo ide, ie hylaluminum, ime hylaluminum, o mix u es he eo . In Table 4, he mos common coca alys s o ansi ion me al ca alyzed ole in dime iza ion and polyme iza ion eac ions a e lis ed.[5c, 10] In o de o ob ain a ough o e iew o e he cos dimensions o hese ac i a o s, he p ices o one mol o coca alys we e calcula ed om he cheapes p ice pe uni gi en by common comme cial labo a o y chemical supplie s. O cou se, he p ice s uc u e may be comple ely di e en o la ge scale applica ions. Howe e , he o de o magni ude can be es ima ed. Pe luo ina ed o ganobo on coca alys s, which a e mainly applied o he ac i a ion o me allocene complexes,[10u, 10 ] a e ex emely expensi e. Al hough hey a e only used in s oichiome ic amoun s, hei p ices p e en hei use o low cos dime iza ion ca alys s. The mos common aluminum coca alys , MAO, is also he mos expensi e one. The di icul syn hesis und subsequen ly he high p ice o MAO is ce ainly also esponsible o he ac ha g oup IV me allocene based sys ems s ill ha e a niche exis ence. Al hough o he alkylaluminum coca alys s a e less expensi e han MAO, he pe ec coca alys would be AlCl3. Aluminum chlo ide is among he cheapes chemicals a ailable. Un o una ely, AlCl3 is insoluble in hyd oca bon sol en s[11] and ca alyzes side eac ions like isome iza ion, c acking, disp opo iona ion o alkanes as well as alkyla ion o a oma ics wi h ole ins and ca ionic oligome iza ion o alkenes.[4, 12] Fu he mo e, he p oposed mechanism based on he inse ion o monome s in o Ni–H o Ni–C bonds o nickel(II) complexes equi es an alkyla ing agen . Alkylaluminum compounds a e py opho ic and highly sensi i e o wa e , oxygen, o pola impu i ies. Thus, hey a e mos ly he cos de e mining ac o o comme cial applica ions. Feed s eams ha e o be pu i ied ho oughly p io o he eac ion, and he high eac i i y equi es a cau ious handling. Finally, he coca alys is des oyed upon p oduc sepa a ion o he homo- geneous eac ions.[13] 3 O e iew o Thesis Resul s 26 In he cou se o ou sea ch o op imized composi ions, chlo oalumina e mel s wi h a iable Lewis acidi ies and BiPh3 bu e con en s we e sc eened owa ds hei pe o mances in biphasic nickel ca alyzed selec i e p opene dime iza ion eac ions. Sligh ly acidic, highly bu e ed sys ems yielded ex emely selec i e p opene dime iza ion sys ems. Howe e , e en low mel ing, highly Lewis acidic composi ions we e success- ully bu e ed o gi e mo e han 90% dime s om p opene. In combina ion wi h he mel ing poin educ ion o chlo oalumina e mel s upon addi ion o BiPh3, i was possible o syn hesize and sc een 100 di e en o ganic halide sal s o hei pe o mances in nickel ca alyzed selec i e p opene dime iza ion eac ions wi h highly Lewis acidic composi ions. Va ious nickel compounds we e employed as ca alys p ecu so s o yield simila ca aly ic pe o mances. While lowe eac ion empe a u es came along wi h highe dime selec i i ies, he p esence o s e ically demanding icyclohexylphosphine ligands led o he o ma ion o aluable b anched p oduc s. 3.4 Bu e ed Aluminum Chlo ide as Highly E icien Coca alys o Ole in Dime iza ion and Polyme iza ion Reac ions A e he p omising esul s o he biphasic expe imen s, we ied o ans e he p inciple o dono -accep o in e ac ions be ween weak o ganic bases and AlCl3 in ionic liquid coca alys s o homogeneous sys ems. In combina ion wi h s oichiome ic amoun s o BiPh3 o N-me hylpy ole bu e , aluminum chlo ide dissol ed in oluene and me hylene chlo ide o o m a highly e icien and ai s able coca alys o nickel complexes. Depending on he ligand s uc u e o he nickel ca alys p ecu so , he esul ing ca alys composi ions we e able o ei he polyme ize e hene o o selec i ely dime ize a ious α- ole ins. Fu he , he Lewis acidi ies o hese bina y homogeneous coca alys solu ions 3 O e iew o Thesis Resul s 27 could be uned p ecisely by he choice o he sol en and he ype and amoun o bu e . The p ope ies o he p oduced polye hylenes could be in luenced by he coca alys composi ions. Also, he bu e su icien ly supp essed isome iza ion eac ions o he α- ole inic p oduc s and hinde ed he ligand abs ac ion om he ac i e nickel ca alys by AlCl3 o he Lewis acidic ionic liquid. The dono -accep o in e ac ion be ween BiPh3 o N-me hylpy ole and AlCl3 was moni o ed by 27Al NMR spec oscopy. E hene polyme i- za ion also occu ed in bu e ed chlo oalumina e ionic liquids in he p esence o a nickel diimine complex. 3.5 Silica Suppo ed Coca alys s o Ole in Dime iza ion and Polyme iza ion Reac ions wi h Nickel Complexes In combina ion wi h BiPh3 o N-me hylpy ole bu e s, E AlCl2 o E 2AlCl su ace modi ied silicas we e success ully employed as he e ogeneous coca alys s o nickel complexes o ca alyze selec i e ole in dime iza ion eac ions. The bu e ed he e o- geneous coca alys s we e also able o ac i a e a nickel diimine complex o e hene polyme iza ion eac ions. The ac i e nickel species we e immobilized a he silica su ace o p oduce a g anula polye hylene-silica composi e ma e ial wi h a homo- geneous pa icle size dis ibu ion. Fu he , su ace modi ied silica was coa ed wi h a BiPh3 bu e ed chlo oalumina e ionic liquid o gi e a suppo ed ionic liquid phase (SILP) coca alys s o nickel ca alyzed ole in dime iza ion eac ions. 3 O e iew o Thesis Resul s 28 3.6 Solubili y Beha iou o TiCl4, Z Cl4, and H Cl4 in Chlo oalumina e Ionic Liquids In he cou se o he ionic liquid coca alys de elopmen , we ound ha up o s oichio- me ic amoun s o Z Cl4 and H Cl4 dissol ed in a neu al chlo oalumina e mel . The high Lewis acidi ies o he esul ing solu ions acc ued om he o ma ion o [Al2Cl7]– anions om [AlCl4]– in he p esence o Z Cl4 o H Cl4. F om such e na y mix u es, c ys als o [Ti2Cl10][BMIM]2, [Z 2Cl10][BMIM]2, and [H 2Cl9][PhNMe3] we e ob ained, and hei c ys al s uc u es we e de e mined. 3.7 Oxida i e Coupling and Ca aly ic C acking o Alkanes in Lewis Acidic Chlo oalumina e Ionic Liquids Enhanced by Molecula Oxygen While expe imen ing wi h ou highly Lewis acidic chlo oalumina e ionic liquid coca alys s o biphasic ole in dime iza ion eac ions, we obse ed ha sa u a ed hyd oca bons like n-hep ane we e e icien ly c acked in he p esence o molecula oxygen. In d y ai , he con e sion o n-hep ane o gi e mainly gaseous alkanes was mo e han one o de o magni ude highe compa ed o sys ems wi h ine a mosphe e. Fu he , cyclic alkanes we e oxida i ely coupled in he p esence o O2 unde he consump ion o wo hyd ogen a oms, while he same eac ions only yielded skele al isome s in a gon a mosphe e. 3 O e iew o Thesis Resul s 29 3.8 Indi idual Con ibu ion o Join Publica ions The esul s p esen ed in his hesis we e ob ained in collabo a ion wi h o he s and a e o be submi ed as indica ed below. In he ollowing, he con ibu ions o all he co-au ho s o he di e en publica ions a e speci ied. The as e isk deno es he co esponding au ho . Chap e 4 This wo k is o be submi ed wi h he i le “Hea y Me al wi h Hea y Impac : Ole in Dime iza ion Reac ions in T iphenylbismu h Bu e ed Chlo oalumina e Ionic Liquids” Ma hias Dö e l and Helmu G. Al * I syn hesized all compounds, ionic liquids and pe o med he ca aly ic expe imen s p esen ed in his wo k. I also w o e he publica ion. Ch is ian Gö l was in ol ed in mechanis ic discussions. Helmu G. Al co ec ed and commen ed he manusc ip . Chap e 5 This wo k is o be submi ed wi h he i le “Facile Syn hesis o new Ca ionic T iphenylphosphine De i a i es and hei Use o P opene Dime iza ion Reac ions in Bu e ed Chlo oalumina e Ionic Liquids” Ma hias Dö e l, Pe e Thoma, and Helmu G. Al * I syn hesized all compounds, ionic liquids and pe o med he ca aly ic expe imen s. Fu he , I w o e he publica ion. I also cha ac e ized all p oduc s. Pe e Thoma helped me measu ing he NMR spec a o he e oa oms and was in ol ed in scien i ic discussions, commen s and co ec ion o he manusc ip . Helmu G. Al co ec ed and commen ed he manusc ip . 3 O e iew o Thesis Resul s 30 Chap e 6 This wo k is o be submi ed wi h he i le “Nickel Ca alyzed P opene Dime iza ion Reac ions in BiPh3 Bu e ed Chlo oalumina e Ionic Liquids: High Pe o mance wi h Uncon en ional Ca ions” Ma hias Dö e l and Helmu G. Al * I syn hesized all compounds, ionic liquids and pe o med he ca aly ic expe imen s. Fu he , I w o e he publica ion. Helmu G. Al co ec ed and commen ed he manusc ip . Chap e 7 This wo k is o be submi ed wi h he i le “Bu e ed Aluminum Chlo ide as Highly E icien Coca alys o Ole in Dime iza ion and Polyme iza ion Reac ions” Ma hias Dö e l and Helmu G. Al * I syn hesized all compounds, ionic liquids and pe o med he ca aly ic expe imen s. Fu he , I w o e he publica ion. Pe e Thoma helped me measu ing he 27Al NMR spec a. Win ied K e schme did he high empe a u e GPC measu emen s. Helmu G. Al co ec ed and commen ed he manusc ip . Chap e 8 This wo k is o be submi ed wi h he i le “Silica Suppo ed Coca alys s o Ole in Dime iza ion and Polyme iza ion Reac ions wi h Nickel Complexes” Ma hias Dö e l and Helmu G. Al * 3 O e iew o Thesis Resul s 31 I syn hesized all compounds, ionic liquids and pe o med he ca aly ic expe imen s. Fu he , I w o e he publica ion. Win ied K e schme did he high empe a u e GPC measu emen . Helmu G. Al co ec ed and commen ed he manusc ip . Chap e 9 This wo k is o be submi ed wi h he i le “Solubili y Beha iou o TiCl4, Z Cl4, and H Cl4 in Chlo oalumina e Ionic Liquids” Ma hias Dö e l, Isabelle Haas, and Helmu G. Al * I syn hesized all compounds, ionic liquids and pe o med he ca aly ic expe imen s. Fu he , I w o e he publica ion. Ge mund Gla z, Tobias Baue and Isabelle Haas pe o med one X- ay analysis each and sol ed he c ys al s uc u es. Isabelle Haas helped me u ilizing he X- ay da a. Helmu G. Al co ec ed and commen ed he manusc ip . Chap e 10 This wo k is o be submi ed wi h he i le “Oxida i e Coupling and Ca aly ic C acking o Alkanes in Lewis Acidic Chlo oalumina e Ionic Liquids Enhanced by Molecula Oxygen” Ma hias Dö e l and Helmu G. Al * I syn hesized all compounds, ionic liquids and pe o med he ca aly ic expe imen s. Fu he , I w o e he publica ion. Helmu G. Al co ec ed and commen ed he manusc ip . 4 Hea y Me al wi h Hea y Impac : Ole in Dime iza ion Reac ions in T iphenylbismu h Bu e ed Chlo oalumina e Ionic Liquids 32 4 Hea y Me al wi h Hea y Impac : Ole in Dime iza ion Reac ions in T iphenylbismu h Bu e ed Chlo oalumina e Ionic Liquids Ma hias Dö e l[a] and Helmu G. Al *[a] [a] Leh s uhl ü Ano ganische Chemie II, Uni e si ä ss aße 30, NW I, 95440 Bay eu h, Ge many. E-mail: [email p o ec ed] Keywo ds: ionic liquids, chlo oalumina es, nickel, biphasic ca alysis, dime iza ion Manusc ip o be submi ed (Communica ion) 4.1 Main Tex Since ionic liquids ecei ed b oade a en ion as a new class o eac ion media in he 1980s,[1] when AlCl3 based sys ems we e ho oughly in es iga ed, many gene a ions o ai and wa e s able ionic liquid sys ems ha e been de eloped.[2] A p esen , he e a e nume ous ionic liquid based sys ems and p ocesses ha ha e ound applica ions in indus y.[2b, 3] Howe e , many o he newly de eloped sys ems wi h imp o ed s abili ies and p ope ies a e based on ionic liquids con aining uncommon anions. These ionic liquids a e e y expensi e, especially when luo ine a oms a e in ol ed. Thus, i is no a big su p ise ha he la ges indus ial p ocesses s ill ely on cheap i s gene a ion chlo oalumina e sys ems. 4 Hea y Me al wi h Hea y Impac : Ole in Dime iza ion Reac ions in T iphenylbismu h Bu e ed Chlo oalumina e Ionic Liquids 33 Pe oChina’s Ionikyla ion® p ocess uses a composi e AlCl3 / CuCl ionic liquid, which ca alyzes he alkyla ion o isobu ane wi h bu enes. The p ocess is cu en ly ope a ed in an 65000 /a alkyla ion uni in China.[4] Chau in e al. de eloped a p ocess o biphasic ca aly ic dime iza ion eac ions o sho chain ole ins in he 1990s.[5] The ionic liquid made om N,N’-alkylme hylimidazolium chlo ide mixed wi h aluminum chlo ide and e hylaluminum dichlo ide plays a dual ole as coca alys and sol en o he ca aly ically ac i e nickel complex. The Ins i u F ançais du Pé ole (IFP) b ough his so called DIFASOL® p ocess o indus ial applica ion by e o i ing i o hei exis ing DIMERSOL® uni s.[6] In he yea 2009, 35 DIMERSOL® uni s ha e been licensed[7] o selec i e dime iza ion eac ions o C3 and C4 ole inic cu s.[6c] Typically, hese p ocesses a e ope a ed wi h capaci ies be ween 20000 and 90000 /a. The biphasic DIFASOL® p ocess p o ides se e al ad an ages o e i s homogeneous DIMERSOL® analogue, which is based on nickel complexes ac i- a ed wi h E AlCl2 in solu ion.[8] The nickel ca alys and mos o he alkylaluminum species emain wi hin he ionic liquid phase. Thus, he nickel and aluminum consump- ion is g ea ly educed. DIFASOL® shows highe selec i i ies o gi e dime s and can be ope a ed wi h s eams con aining smalle amoun s o ole ins. In combina ion wi h a much smalle eac o size, his leads o g ea ly imp o ed p ocess economics.[6b, 6c] Besides DIFASOL®, which uses e hylaluminum g oups o supp ess uncon olled ca ionic ole in oligome iza ion eac ions in solely AlCl3 based ionic liquids,[9] Wasse scheid e al. de eloped a sys em bu e ed by weak o ganic bases.[10] Py idine, quinoline and py ole de i a i es we e added o sligh ly acidic chlo oalumina e ionic liquids. The in e ac ion o he Lewis bases wi h AlCl3 o he [Al2Cl7]– species p esen in such liquids[1a, 11] educed he “la en acidi y”.[12] The in e ac ion p e en ed uncon olled ca ionic ole in oligome iza ion eac ions. A chlo oalumina e liquid bu e ed wi h weak o ganic bases was success ully employed o ac i a e nickel complexes o dime iza ion eac ions o 1-bu ene. In a ecen a icle, Wasse scheid e al. ex ended he sys em o p opene and 1-hexene dime iza ion eac ions and s udied he kine ics o hese biphasic eac ions in de ail.[13] They ound ha he eac ion a es a e s ongly limi ed by mass ans e o he subs a e ole ins. Following he concep o Lewis base bu e ed sys ems we ound ha ia ylamine, ia ylphosphine and ia ylbismu h compounds e icien ly bu e ionic liquids de i ed 4 Hea y Me al wi h Hea y Impac : Ole in Dime iza ion Reac ions in T iphenylbismu h Bu e ed Chlo oalumina e Ionic Liquids 34 om AlCl3. The dissolu ion o small amoun s o hese bu e ing subs ances in a sligh ly acidic 1-bu yl-3-me hylimidazolium (BMIM) chlo oalumina e ionic liquids (AlCl3 / BMIMCl = 1.20) yielded he ionic liquid coca alys s. The ai s able bis(imino)py idine complex o nickel(II)b omide (Figu e 1) was used as nickel sou ce. I eadily dissol ed in he bu e ed ionic liquids and he esul ing ionic liquid ca alys s dime ized p opene in ba ch expe imen s wi h high p oduc i i ies and selec i i ies (Table 1). Figu e 1: Ca alys p ecu so used o biphasic p opene dime iza ion eac ions. We subs i u ed he e m “ac i i y” wi h “p oduc i i y” ollowing he esul s o Wasse - scheid e al.[13] They showed ha abo e a ce ain concen a ion, he ac i i ies o he sys ems did no depend on he amoun o ca alys anymo e due o mass anspo limi a ions. The ac i i ies we e hen e en independen om he empe a u e. Fo ou sys em we chose a ca alys concen a ion o 10–5 molca alys / gionic liquid. A da a se o a ca alys concen a ion se ies can be ound in he Suppo ing In o ma ion. The minimum ca alys concen a ion ha s ill in luenced he o e all ac i i y in he in es iga ed sys ems was ound o be a ound 10–6 molca alys / gionic liquid. Thus, he p oduc i i ies could be calcula ed as he amoun o p oduc s o med by one g am o ac i e liquid in one hou unde he assump ion ha he p oduc i i ies o he sys ems did no depend on he ca alys concen a ion. Fo a ypical ca aly ic expe imen , 2 – 4 ml ionic liquid we e mixed wi h he co esponding amoun o bu e ollowed by he addi ion o he ca alys p ecu so (1). Be ween 2.5 and 4 g o he esul ing homogeneous solu ions we e used o he expe imen s. 4 Hea y Me al wi h Hea y Impac : Ole in Dime iza ion Reac ions in T iphenylbismu h Bu e ed Chlo oalumina e Ionic Liquids 35 Table 1: Nickel ca alyzed biphasic p opene dime iza ion eac ions in bu e ed acidic 1- bu yl-3-me hylimidazolium (BMIM) chlo oalumina e ionic liquids.[1] No. Bu e [Bu e ] / [BMIMCl] P oduc i i y[2] Dime s [%] 1 NPh3 0.12 4.0 81.0 2 PPh3 0.12 > 15.0[3] 93.6 3 AsPh3 0.12 0 – 4 SbPh3 0.12 6.8 Oil[4] 5 BiPh3 0.07 > 10.8[3] 89.2 6 BiPh3 0.12 > 10.8[3] 93.1 7 BiPh3 0.30 6.7 96.0 [1] Reac ion condi ions: 2 ml o ionic liquid wi h [AlCl3] / [BMIMCl] = 1.20; ca alys p ecu so 1; [ca ] = 10–5 mol / gionic liquid; T = 25°C; s i ing a e = 1200 min–1; = 60 min; 300 ml glass au ocla e; 40 – 60 ml liquid p opene. [2] gp oduc / gionic liquid x h. [3] Comple e con e sion. [4] Highe oligome s de i ed om a ca ionic oligome iza ion eac ion. While he iphenylamine bu e ed sys em p oduced only 81% dime s (1), he iphenylphosphine based sys em wi h he same composi ion ga e 94% dime s (2). Howe e , he solubili y o PPh3 s ongly depended on he empe a u e. A 25°C, PPh3 did no dissol e comple ely in he ionic liquid. Due o i s nonpola cha ac e , iphenylphosphine sys ems su e ed om hea y leaching in o he o ganic p oduc phase. Thus, he esul s s ongly depended on he amoun o ole in o he eac ion empe a u e and, he e o e, displayed a bad ep oducibili y. The addi ion o AsPh3 deac i a ed he sys em (3), while SbPh3 (4) showed no abili y o p e en ca ionic ole in oligome iza ion eac ions induced by he highly Lewis acidic aluminum cen e s.[9] Unexpec edly, he iphenyl compound o he las elemen in he ow, bismu h, p o ed o be a pe ec bu e . S a ing om a concen a ion o 0.07 equi alen s o BiPh3, he BiPh3 bu e ed sys ems p oduced dime s wi h high selec i i ies (5 – 7). I was comple ely soluble in chlo oalumina e ionic liquids, e en a highe a ios. The e a e h ee easons o i s high solubili y. Fi s , a oma ic compounds eadily dissol e in chlo oalumina e ionic 4 Hea y Me al wi h Hea y Impac : Ole in Dime iza ion Reac ions in T iphenylbismu h Bu e ed Chlo oalumina e Ionic Liquids 42 phase is a majo p oblem o DIFASOL® sys ems. The e o e, hey a e ope a ed in combina ion wi h DIMERSOL® eac o s, which o ally pu i y he DIFASOL® eed.[6c] Howe e , he absence o any alkylaluminum compounds a ose ques ions abou he dime iza ion mechanism. In he li e a u e, a mechanism is gene ally accep ed o wo- alen nickel complexes ha in ol es Ni–H o Ni–C bonds.[7, 18] In all o hese cases i was assumed ha he nickel cen e is alkyla ed by he aluminum coca alys o o m nickel hyd ide o nickel alkyl species. Al e na i ely, Ni–C bond con aining species like η3-allyl nickel compounds we e employed.[18g] The ole ins coo dina e o a ee coo di- na ion si e a he squa e plana nickel cen e and a e inse ed in o he Ni–H o Ni–C bond. Ye , his mechanism could no be applied o ou sys em. Besides a nickel sal , bu e ed chlo oalumina e mel s only con ained AlCl3, an o ganic halide sal and he bu e . None o hese is able o o m ei he Ni–H o Ni–C bonds om nickel halide sal s. Also, he educ ion o Ni(II) o gi e Ni(I) o Ni(0) species was unlikely in hese sys ems. Fo nickel compounds in lowe oxida ion s a es han wo, al e na i e mechanisms we e also discussed. Fo example, nickel(I) compounds a e in ol ed in selec i e ole in oligome iza ion eac ions wi h nickel imp egna ed me al oxides. Fo his eac ion, a nickelacyclopen ane was p oposed, which is in equilib ium wi h he co esponding di- ole in complex. The a e de e mining s ep was assumed o be he decomposi ion o he me allacycle o yield he dime upon educ i e elimina ion.[19] Fo Ni(0), me allacycles a e also well known.[20] Since he p oduc dis ibu ion esul ing om selec i e p opene dime iza ion eac ions wi h ca alys p ecu so 1 ma ched he esul s o ligand ee nickel sal s,[13] we expec ed ha he ligand was abs ac ed. Nickel halides we e ound o o m Ni(AlCl4)2[21] o [Ni(AlCl4)3]–,[22] i hey we e mixed wi h aluminum chlo ide o acidic chlo oalumina e ionic liquids, espec i ely. In bu e ed chlo oalumina e mel s used o ole in dime iza ion eac ions, hese weakly coo dina ing e achlo oalumina e anions a e expec ed o be easily eplaced by o he ligands like bu e o ole in molecules (Figu e 2). Conside ing ou ca aly ic esul s, we p opose a new mechanism o nickel ca alyzed ole in dime iza ion eac ions in bu e ed, alkylaluminum ee chlo oalumina e ionic liquids using he example o e hene (Scheme 3). Simila o he mechanism p oposed o Ni(I),[19] we expec he o ma ion o a me allacycle, which is in equilib ium wi h a Ni(e hene)2 complex. Decomposi ion o he me allacycle h ough β-H elimina ion yields 4 Hea y Me al wi h Hea y Impac : Ole in Dime iza ion Reac ions in T iphenylbismu h Bu e ed Chlo oalumina e Ionic Liquids 43 an ω-alkenyl s abilized nickel hyd ide species. Elimina ion ollowed by he coo dina ion o a new e hene molecule esul s in a nickel di-ole in complex wi h e hene and 1-bu ene being coo dina ed o he nickel cen e . A his poin , he e a e wo possible pa hways. Fo weakly bu e ed, mo e acidic composi ions, 1-bu ene emains a he nickel cen e and o ms an e hyl b anched nickelacyclopen ane again. This ou e would lead o he o ma ion o b anched, highe oligome s om e hene. Ye , i he sys em is highly bu e ed, we expec he bu e o compe e wi h 1-bu ene o he coo dina ion si e a he ac i e nickel cen e . Since he coo dina ion s eng h o 1-bu ene is weake compa ed o e hene, 1-bu ene is eplaced by a bu e molecule. The also weakly coo dina ing bu e molecule can be subs i u ed again by an e hene molecule o o m he ini ial Ni(e hene)2 species. Figu e 2: Fo ma ion o [Ni(AlX4)3]– om nickel halide sal s in acidic haloalumina e ionic liquids (a) and exchange o he weakly coo dina ing e ahaloalumina e ligands by compe ing dono molecules (b). Al hough we ha e no expe imen al e idence o he oxida ion s a e o he ac i e nickel ca alys , we p opose ha he ac i e species is Ni(II). Due o he o ma ion o weakly coo dina ing e ahaloalumina e anions in acidic ionic liquids,[22] he Ni(II) cen e is easily accessible. The mechanism con enien ly includes a me allacycle as well as a Ni–H species. Also, ou esul s indica ed ha he o iginal p oduc om e hene dime iza ion eac ions was 1-bu ene. Howe e , subsequen isome iza ion eac ions disguised he eal p oduc dis ibu ions. This became clea since he selec i i y o gi e 1-bu ene inc eased om 28% (19) o 47% (20) wi h wice he amoun o bu e . Thus, he bu e did no only bu e Lewis acidic aluminum species, i also a ou ed he o ma ion o dime s and supp essed subsequen isome iza ion eac ions. 4 Hea y Me al wi h Hea y Impac : Ole in Dime iza ion Reac ions in T iphenylbismu h Bu e ed Chlo oalumina e Ionic Liquids 44 Scheme 3: P oposed mechanism o nickel ca alyzed e hene dime iza ion eac ions in bu e ed chlo oalumina e ionic liquids (L = any ligand, B = bu e molecule). Finally, an E AlCl2 based chlo oalumina e ionic liquid simila o a comme cial DIFASOL® composi ion[23] was modi ied wi h ou BiPh3 bu e and es ed in ba ch p opene dime iza ion eac ions (Table 5). The unmodi ied sys em ga e abou 80% dime s (27) wi h ca alys p ecu so 1. I small amoun s o BiPh3 we e dissol ed in ha sys em, he dime yield jumped o almos 97%. The addi ion o 0.03 equi alen s (30) ga e he bes esul in combina ion wi h a high p oduc i i y. I oo much bu e was added, he p oduc i i ies we e educed (28, 29), while no e ec could be obse ed wi h only 0.01 equi alen s (31) o BiPh3. 4 Hea y Me al wi h Hea y Impac : Ole in Dime iza ion Reac ions in T iphenylbismu h Bu e ed Chlo oalumina e Ionic Liquids 45 Table 5: Nickel ca alyzed biphasic p opene dime iza ion eac ions in ypical DIFASOL® sys ems modi ied wi h BiPh3. [1] No. [E AlCl2] / [BMIMCl] [BiPh3] / [BMIMCl] P oduc i i y[2] Dime s [%] 27 0.20 0 > 18.1[3] 79.6 28 0.20 0.12 2.0 96.8 29 0.20 0.06 7.1 94.6 30 0.20 0.03 > 19.4[3] 94.1 31 0.20 0.01 > 13.0[3] 79.4 32 0 0.12 > 10.8[3,4] 93.1 [1] Reac ion condi ions: 2.5 – 4.0 g bu e ed ionic liquid; [AlCl3] / [BMIMCl] = 1.20; ca alys p ecu so 1; [ca ] = 10–5 mol / gionic liquid; T = 25°C; s i ing a e = 1200 min–1; = 45 min; 300 ml glass au ocla e; 40 – 60 ml liquid p opene. [2] gp oduc / gionic liquid x h. [3] Comple e con e sion. [4] Reac ion ime 60 minu es. The combina ion o E AlCl2 and BiPh3 wi h AlCl3 based ionic liquids p o ides a p omising, highly ac i e and selec i e nickel ca alyzed dime iza ion sys em o comme cial applica ions. The ac ha BiPh3 educes he mel ing empe a u es o said sys ems opens he doo o he applica ion o a wide ange o cheap ca ions. The possibili y o une he Lewis acidi ies and o supp ess subsequen isome iza ion eac ions simply by a ying he BiPh3 con en should make BiPh3 bu e ed chlo oalumina e ionic liquids in e es ing o many o he ypes o eac ions like F iedel C a s alkyla ions, acyla ions, isome iza ions, hyd ogena ions,[2b, 24] and many mo e. Suppo ing In o ma ion A ailable De ailed expe imen al p ocedu es, he p epa a ion o he ammonium sal s, ionic liquids and complex 1 as well as a ca alys concen a ion se ies a e desc ibed in he Suppo ing In o ma ion. 4 Hea y Me al wi h Hea y Impac : Ole in Dime iza ion Reac ions in T iphenylbismu h Bu e ed Chlo oalumina e Ionic Liquids 46 Acknowledgemen s Financial suppo by ConocoPhillips, USA, is g a e ully acknowledged. M.D. hanks D . C. Gö l o he help ul discussions and he Eli e Ne wo k o Ba a ia (ENB) wi hin he g adua e p og am “Mac omolecula Science”. 4.2 Re e ences [1] a) J. S. Wilkes, J. A. Le isky, R. A. Wilson, C. L. Hussey, Ino g. Chem. 1982, 21, 1263-1264; b) C. L. Hussey, Pu e Appl. Chem. 1988, 60, 1763-1772. [2] a) P. Wasse scheid, W. Keim, Angew. Chem., In . Ed. 2000, 39, 3772-3789; b) H. Oli ie -Bou bigou, L. Magna, D. Mo an, Appl. Ca al., A 2010, 373, 1-56. [3] N. V. Plechko a, K. R. Seddon, Chem. Soc. Re . 2008, 37, 123-150. [4] Z. C. Liu, R. Zhang, C. M. Xu, R. G. Xia, Oil Gas J. 2006, 104, 52-56. [5] a) Y. Chau in, B. Gilbe , I. Guiba d, J. Chem. Soc.-Chem. Commun. 1990, 1715-1716; b) Y. Chau in, S. Einlo , H. Oli ie , Ind. Eng. Chem. Res. 1995, 34, 1149-1155; c) S. Einlo , F. K. Die ich, R. F. De Souza, J. Dupon , Polyhed on 1996, 15, 3257-3259; d) Y. Chau in, H. Oli ie , C. N. Wy alski, L. C. Simon, R. F. de Souza, J. Ca al. 1997, 165, 275-278. [6] a) F. Fa e, A. Fo es ie e, F. Hugues, H. Oli ie -Bou bigou, J. A. Chodo ge, Oil Gas Eu . Mag. 2005, 31, 83 - 91; b) B. Gilbe , H. Oli ie -Bou bigou, F. Fa e, Oil & Gas Science and Technology - Re . IFP 2007, 62, 745-759; c) H. Oli ie - Bou bigou, F. Fa e, A. Fo es iè e, F. Hugues, Ionic Liquids and Ca alysis: he IFP Biphasic Di asol P ocess, in Handbook o G een Chemis y, Wiley-VCH, 2010, pp. 101-126. [7] A. Fo es iè e, H. Oli ie -Bou bigou, L. Saussine, Oil & Gas Science and Technology - Re . IFP 2009, 64, 649-667. [8] a) Y. Chau in, J. F. Gailla d, D. V. Quang, J. W. And ews, Chem. Ind. 1974, 375- 378; b) D. Comme euc, Y. Chau in, G. Lege , J. Gailla d, Oil & Gas Science and Technology - Re . IFP 1982, 37, 639-649. [9] a) M. Goledzinowski, V. I. Bi ss, J. Galuszka, Ind. Eng. Chem. Res. 1993, 32, 1795-1797; b) O. S enzel, R. B üll, U. M. Wahne , R. D. Sande son, H. G. Raubenheime , J. Mol. Ca al. A: Chem. 2003, 192, 217-222. [10] a) P. Wasse scheid, WO 9847616, 1998; b) B. Ellis, W. Keim, P. Wasse scheid, Chem. Commun. 1999, 337-338; c) P. Wasse scheid, M. Eichmann, Ca al. Today 2001, 66, 309-316; d) D. S. McGuinness, W. Muelle , P. Wasse scheid, K. J. Ca ell, B. W. Skel on, A. H. Whi e, U. Engle , O ganome allics 2001, 21, 175- 181. [11] C. L. Hussey, T. B. Sche le , J. S. Wilkes, J. A. A. Fannin, J. Elec ochem. Soc. 1986, 133, 1389-1391. 4 Hea y Me al wi h Hea y Impac : Ole in Dime iza ion Reac ions in T iphenylbismu h Bu e ed Chlo oalumina e Ionic Liquids 47 [12] a) I. C. Qua mby, R. A. Man z, L. M. Goldenbe g, R. A. Os e young, Anal. Chem. 1994, 66, 3558-3561; b) I. C. Qua mby, R. A. Os e young, J. Am. Chem. Soc. 1994, 116, 2649-2650. [13] M. Eichmann, W. Keim, M. Haumann, B. U. Melche , P. Wasse scheid, J. Mol. Ca al. A: Chem. 2009, 314, 42-48. [14] a) Y. Chau in, S. Einlo , H. Oli ie , Ind. Eng. Chem. Res. 1995, 34, 1149-1155; b) A. A. Fannin, L. A. King, J. A. Le isky, J. S. Wilkes, J. Phys. Chem. 1984, 88, 2609-2614; c) J. Robinson, R. C. Bugle, H. L. Chum, D. Ko an, R. A. Os e young, J. Am. Chem. Soc. 1979, 101, 3776-3779. [15] a) F. H. Hu ley, J. T. P. Wie , J. Elec ochem. Soc. 1951, 98, 203-206; b) A. A. Fannin, D. A. Flo eani, L. A. King, J. S. Lande s, B. J. Pie sma, D. J. S ech, R. L. Vaughn, J. S. Wilkes, L. Williams John, J. Phys. Chem. 1984, 88, 2614-2621. [16] R. M. S ephenson, J. Chem. Eng. Da a 1993, 38, 625-629. [17] F. Pe uch, H. C amail, A. De ieux, Mac omolecules 1999, 32, 7977-7983. [18] a) W. Keim, Ann. N.Y. Acad. Sci. 1983, 415, 191-200; b) U. Mülle , W. Keim, C. K üge , P. Be z, Angew. Chem., In . Ed. 1989, 28, 1011-1013; c) S. A. S ejda, M. B ookha , O ganome allics 1998, 18, 65-74; d) D. P. Ga es, S. A. S ejda, E. Ona e, C. M. Killian, L. K. Johnson, P. S. Whi e, M. B ookha , Mac omolecules 2000, 33, 2320-2334; e) M. D. Lea he man, S. A. S ejda, L. K. Johnson, M. B ookha , J. Am. Chem. Soc. 2003, 125, 3068-3081; ) F. Speise , P. B auns ein, L. Saussine, Acc. Chem. Res. 2005, 38, 784-793; g) D. Roy, R. B. Sunoj, O g. Biomol. Chem. 2010, 8, 1040-1051; h) J. M. B own, G. D. Hughes, Ino g. Chim. Ac a 1996, 252, 229-237. [19] a) F. X. Cai, C. Lepe i , M. Ke ma ec, D. Oli ie , J. Mol. Ca al. 1987, 43, 93-116; b) C. Lepe i , M. Ke ma ec, D. Oli ie , J. Mol. Ca al. 1989, 51, 95-113. [20] a) R. H. G ubbs, A. Miyashi a, J. Am. Chem. Soc. 1978, 100, 7416-7418; b) J. Cámpo a, P. Palma, E. Ca mona, Coo d. Chem. Re . 1999, 193-195, 207-281; c) R. H. G ubbs, A. Miyashi a, M.-I. M. Liu, P. L. Bu k, J. Am. Chem. Soc. 1977, 99, 3863-3864; d) R. H. G ubbs, A. Miyashi a, J. Am. Chem. Soc. 1978, 100, 1300-1302. [21] J. B ynes ad, H. L. Yakel, G. P. Smi h, Ino g. Chem. 1970, 9, 686-686. [22] a) A. K. Abdul-Sada, A. M. G eenway, K. R. Seddon, T. Wel on, O g. Mass. Spec om. 1992, 27, 648-649; b) U. Kebe , R. Mülle , Z.Na u o sch.(B) 2007, 62, 1052-1058. [23] H. Oli ie -Bou bigou, E. Pellie , A. Fo es ie e, EP 1968918, 2008. [24] T. Wel on, Chem. Re . 1999, 99, 2071-2084. 4 Hea y Me al wi h Hea y Impac : Ole in Dime iza ion Reac ions in T iphenylbismu h Bu e ed Chlo oalumina e Ionic Liquids 48 4.3 Suppo ing In o ma ion Gene al Rema ks All chemical manipula ions we e ca ied ou using s anda d Schlenk echniques unde a gon a mosphe e. n-Hep ane was dis illed om Na/K alloy unde an a mosphe e o a gon. The p oduc s o he dime iza ion expe imen s we e cha ac e ized by gas ch oma og aphy (Agilen 6850) and GC-MS (FOCUS DSQ™ The mo Scien i ic). Mass spec a we e eco ded on a Va ian MAT CH7 ins umen (di ec inle sys em, elec on impac ioniza ion 70 eV). Elemen al analyses we e pe o med wi h a Va ioEl III CHN ins umen . Ace anilide was used as a s anda d. E hene (99.9%), p opene (99.3%), and 1-bu ene (99.3%) we e pu chased om Riessne Gase, Lich en els, and we e d ied o e a column packed wi h P4O10. 1-Hexene and E AlCl2 (0.9 M in hep ane) we e pu chased om Ac os and used wi hou u he pu i ica ion. T iphenylamine, iphenyl- phosphine, iphenyla sine, iphenylan imony, iphenylbismu h, and cyclohexylamine hyd ochlo ide we e pu chased om ABCR, 1-bu yl-3-me hylimidazolium chlo ide, 1- e hyl-3-me hylimidazolium chlo ide, 1-py olidino-1-cyclopen ene, ibu ylamine, N- me hylpy olidine, and AlCl3 (Reagen Plus®) we e pu chased om Sigma-Ald ich and used as ecei ed. Chlo oe hane (Chlo ae hyl, D . Henning) was pu chased in a local pha macy. Syn hesis o Complex 1 The ligand p ecu so was syn hesized om 2,6-diace ylpy idine and 4- luo oaniline acco ding o a li e a u e p ocedu e.[1] The ligand p ecu so (1.19 g) was dissol ed in THF (100 ml) and 1.05 g o (dme)NiB 2 we e added. The mix u e was s i ed o 2 h a 4 Hea y Me al wi h Hea y Impac : Ole in Dime iza ion Reac ions in T iphenylbismu h Bu e ed Chlo oalumina e Ionic Liquids 49 ambien empe a u e. A e mos o he sol en had been emo ed in acuo, he complex was p ecipi a ed by he addi ion o n-pen ane (100 ml). A e il a ion and washing wi h n-pen ane, complex 1 was ob ained in quan i a i e yield as an o ange b own solid. EI-MS da a: 567 (M•+) (1), 488 M –B (33), 407 M –2B (22), 349 M –NiB 2 (65), 136 F- C6H4-N=C-CH3 (100). Elemen al analysis (calcula ed, ound o C21H17B 2F2N3Ni): C (44.42, 44.51), H (3.02, 3.56), N (7.40, 7.05). Syn hesis o he Ionic Liquids The ionic liquids we e syn hesized by di ec ly mixing he co esponding amoun o AlCl3 and chlo ide sal in a cooled Schlenk ube. In he case o E AlCl2 con aining sys ems, a 0.9 mola solu ion o E AlCl2 in hep ane was added o he liquid and he sol en was emo ed in acuo. The ob ained ionic liquids we e s o ed in Schlenk ubes. P ocedu e o Dime iza ion Reac ions Using Bu e ed Ionic Liquids P io o he expe imen s, 2 o 4 ml o he ionic liquid we e illed in o a Schlenk ube and mixed wi h he bu e . A e he bu e had dissol ed upon s i ing, he nickel complex 1 was added. The ob ained homogeneous solu ion was sy inged in o he eac ion essel. I s amoun was de e mined by he weigh di e ence o he sy inge. Fo he sc eening expe imen s wi h p opene, a 300 ml glass au ocla e equipped wi h a s i ing ba and a magne ic s i e wi h a s i ing a e o 1200 min–1 was used. The glass au ocla e was kep in a d ying o en a 150°C o se e al hou s be o e an expe imen . A e he addi ion o he ac i e ionic liquid, p opene (40 o 60 ml) was condensed in o he glass au ocla e by liquid ni ogen cooling. Then, he au ocla e was placed in a me al box o sa e y easons, and he empe a u e was egula ed by an ex e nal wa e ba h. A e he expe imen , he p essu e was slowly eleased by opening a al e. The p oduc ac ion was il e ed h ough a sho plug o silica and analyzed by gas ch oma og aphy. Fo he sc eening expe imen s in Table 4 and Table 6, a s i ed 300 ml Pa s ainless s eel au ocla e was used. The s eel essel was kep in a d ying o en a 150°C o 4 Hea y Me al wi h Hea y Impac : Ole in Dime iza ion Reac ions in T iphenylbismu h Bu e ed Chlo oalumina e Ionic Liquids 50 se e al hou s be o e an expe imen , and i was illed wi h a gon. Then, he ac i e ionic liquid was added unde a gon coun e low. E hene: n-Hep ane was added o he eac o essel unde a gon coun e low. The sys em was pu unde acuum, and he empe a u e was aised o 40°C. Then, an e hene p essu e o 10 ba was applied. Cooling o he highly exo he mic eac ion was achie ed manually by an ex e nal liquid ni ogen cooled ace one ba h. A e he expe imen , he essel was quickly cooled o –20°C. The p essu e was eleased, he weigh di e ence o he essel was de e mined, and a cooled sample was di ec ly analyzed by gas ch oma og aphy. P opene: The essel was e acua ed, and liquid p opene (200 ml) was soaked in o i a 77 K. The eac ion was s a ed by quickly hea ing he essel o 40°C wi h boiling wa e . Cooling o he highly exo he mic eac ion was achie ed manually by an ex e nal liquid ni ogen cooled ace one ba h. A e he expe imen , he essel was cooled o 0°C, and he p essu e was slowly eleased. A e eaching ambien empe a u e, he weigh di e ence o he essel was de e mined, and he p oduc phase was analyzed by gas ch oma og aphy. 1-Bu ene: The essel was e acua ed, and liquid 1-bu ene (200 ml) was soaked in o i a –20°C. The eac ion was s a ed by quickly hea ing he essel o 40°C wi h boiling wa e . Cooling o he exo he mic eac ion was achie ed manually by an ex e nal ice ba h. A e he expe imen , he essel was cooled o –20°C, and he o ganic phase was analyzed by gas ch oma og aphy. P oduc i i ies we e calcula ed om he GC spec a. 1-Hexene was added o he eac o essel, and he eac o was s i ed a 40°C. A e he expe imen , he o ganic phase was analyzed by gas ch oma og aphy. P oduc i i ies we e calcula ed om he GC spec a. Syn hesis o he Hyd ochlo ides o T ibu ylamine, 1-Py olidino-1-cyclopen ene and N-Me hylpy olidine The co esponding amines we e dissol ed in d y die hyle he , and HCl gas was bubbled h ough he lask un il no mo e gas was abso bed. The whi e, p ecipi a ed ammonium sal s we e il e ed, washed h ee imes wi h die hyle he and n-pen ane, d ied in acuo and used wi hou u he pu i ica ion. 4 Hea y Me al wi h Hea y Impac : Ole in Dime iza ion Reac ions in T iphenylbismu h Bu e ed Chlo oalumina e Ionic Liquids 51 Syn hesis o N-E hyl-N-me hylpy olidinium Chlo ide N-e hyl-N-me hylpy olidinium chlo ide was syn hesized om chlo oe hane and N- me hylpy olidine in ace oni ile ollowing he p ocedu e desc ibed o ie hylamine in he li e a u e.[2] Ca alys Concen a ion Se ies Table 6: Ca alys concen a ion se ies o nickel ca alyzed biphasic p opene dime iza ion eac ions in BiPh3 bu e ed acidic chlo oalumina e ionic liquids.[1] No. Ca alys Concen a ion[2] P oduc i i y[3] “Ac i i y”[4] Dime s [%] 32 10–5 18.5 1.9 93.7 33 10–6 18.2 18.2 92.9 34 10–7 9.7 97.1 92.1 35 10–8 1.9 192.1 92.2 [1] Reac ion condi ions: 3.5 – 4.5 g bu e ed ionic liquid; [BiPh3] / [N-me hylpy olidinium]+[Al2Cl7]− = 0.30; ca alys p ecu so 1; T = 40°C; s i ing a e = 600 min–1; = 60 min; s i ed 300 ml Pa s ainless s eel au ocla e; 200 ml liquid p opene. [2] molca alys / gionic liquid. [3] gp oduc / gionic liquid x h. [4] p oduc / molca alys x h. Re e ences [1] C. Qian, F. Gao, Y. Chen, L. Gao, Synle 2003, 1419-1422. [2] N. W. Smi h, J. McCloskey, US 6444846, 2002. 5 Facile Syn hesis o new Ca ionic T iphenylphosphine De i a i es and hei Use o P opene Dime iza ion Reac ions in Bu e ed Chlo oalumina e Ionic Liquids 58 Scheme 2: T ia ylphosphines sc eened owa ds hei bu e ing abili y in he Lewis acidic ionic liquid [BMIM]+[Al2Cl7]−. The p opene dime iza ion eac ions we e ca ied ou ba chwise employing a simple bis(imino)py idine complex o nickel(II)b omide (15) as he ca alys p ecu so .[17] Figu e 1: Ca alys p ecu so used o biphasic p opene dime iza ion eac ions. Table 1 summa izes he esul s o he p opene dime iza ion eac ions wi h di e en bu e ing subs ances. All dime iza ion eac ions ca alyzed by complex 15 yielded a simila dime dis ibu ion consis ing o abou 25% n-hexenes, 69% 2-me hylpen enes, and 6% 2,3-dime hylbu enes (± 2%). Ob iously, he ligand had no e ec on he p oduc dis ibu ions, which we e simila o he dis ibu ion o a ligand ee nickel sal .[16] As desc ibed in ou ecen publica ion,[17] he e m “ac i i y” was eplaced by he e m 5 Facile Syn hesis o new Ca ionic T iphenylphosphine De i a i es and hei Use o P opene Dime iza ion Reac ions in Bu e ed Chlo oalumina e Ionic Liquids 59 “p oduc i i y”. Wasse scheid e al. showed ha abo e a ce ain concen a ion, he ac i i ies o he sys ems did no depend on he amoun o ca alys anymo e due o mass anspo limi a ions.[16] Thus, he p oduc i i ies can be calcula ed as he amoun o p oduc s o med by one g am o ac i e liquid in one hou unde he assump ion ha he p oduc i i ies o he sys ems do no depend on he ca alys concen a ion. Table 1: Nickel ca alyzed biphasic p opene dime iza ion eac ions in bu e ed acidic 1- bu yl-3-me hylimidazolium (BMIM) chlo oalumina e ionic liquids.[1] Bu e P oduc i i y[2] Dime s [%] NPh3 > 8.6[3] 68.0 9 > 12.2[3] 57.4 10 2.9 53.5 11 6.3 78.6 12 3.7 Oil[4] 13 > 12.8[3] 69.3 14 0.4 Oil[4] 8 6.1 84.1 5 11.6 Oil[4] BiPh3 > 9.3[3] 85.5 [1] Reac ion condi ions: 2 – 3 g bu e ed ionic liquid; composi ion [bu e ] / [BMIM]+[Al2Cl7]− = 0.30; ca alys p ecu so 15; [ca ] = 10–5 mol / gionic liquid; T = 25°C; s i ing a e = 1200 min–1; = 60 min; 300 ml glass au ocla e; 40 – 60 ml liquid p opene. [2] gp oduc / gionic liquid x h. [3] Comple e con e sion. [4] Highe oligome s de i ed om a ca ionic oligome iza ion eac ion. T iphenylamine ce ainly coo dina ed oo s ongly o he aluminum cen e s esul ing in a educed bu e ing abili y coming along wi h a low dime yield o only 68%. The iphenylphosphine sys em lacked selec i i y due o i s low solubili y in he ionic liquid. Mos o he 0.30 bu e equi alen s did no dissol e in he ionic liquid phase. T is(m- chlo ophenyl)phosphine (11) ga e a highe dime yield o 79% due o i s be e solubili y 5 Facile Syn hesis o new Ca ionic T iphenylphosphine De i a i es and hei Use o P opene Dime iza ion Reac ions in Bu e ed Chlo oalumina e Ionic Liquids 60 in he mel compa ed o i s pa a-subs i u ed equi alen (10). The 2-imidazolium- diphenylphosphine (12), which bea ed a ca ionic 1-bu yl-3-me hylimidazolium chlo ide moie y ins ead o a phenyl ing,[3b] showed no bu e ing abili y. Only highe oligome s om uncon olled ca ionic ole in oligome iza ion eac ions ini ia ed by he highly Lewis acidic aluminum cen e s we e ob ained.[10] In con as , diphenylphosphino e ocene (13) su icien ly bu e ed he sys em yielding 69% dime s. The addi ion o he sodium sal o diphenylphosphinobenzene-3-sul onic acid (14) almos deac i a ed he sys em. Only small amoun s o highe oligome s we e o med du ing he eac ion. P obably he oxygen o he sul ona e g oup eac ed wi h chlo oalumina e species deac i a ing he sys em and educing he mobili y o he bu e . As expec ed, he iodide sal o he syn hesized ionic phosphine 8 ga e he bes esul o all es ed phosphines p o iding 84% dime s. I was comple ely soluble in he ionic liquid and almos caugh up wi h he BiPh3 sys em (86% dime s[17]). Howe e , i had o be aken in o accoun ha he addi ional iodide ions o he bu e educed he o e all acidi y o he sys em, which also a ou ed he o ma ion o dime s. Su p isingly, he ca ionic phosphine wi h a e a luo obo a e anion 5 did no dissol e in he ionic liquid a all. Hence his sys em only p oduced highe oligome s. E ec s o 8 on E AlCl2 Bu e ed Chlo oalumina e Mel s Addi ionally, he e ec o he ionic phosphine 8 on he pe o mance o a ypical E AlCl2 bu e ed sys em was in es iga ed (Table 2). Fo example, his composi ion is applied in he comme cial DIFASOL® p ocess. In ba ch p opene dime iza ion eac ions, he unmodi ied E AlCl2 bu e ed composi ion yielded abou 80% dime s wi h ca alys p ecu so 15. Addi ion o 0.03 equi alen s o he ca ionic phosphine 8 sligh ly inc eased he C6 selec i i y o 84%. The addi ion o 0.06 equi alen s o 8 esul ed in 89% dime s. The combina ion o E AlCl2 bu e ed sys ems and an ionic phosphine bu e imp o ed he o e all dime selec i i y abou 10% compa ed o a s anda d DIFASOL® sys em while main aining a high p oduc i i y. Any phosphine leaching in o he p oduc phase should be p e en ed by i s ionic cha ac e . A s able sys em wi h a high li e ime is he e o e expec ed. 5 Facile Syn hesis o new Ca ionic T iphenylphosphine De i a i es and hei Use o P opene Dime iza ion Reac ions in Bu e ed Chlo oalumina e Ionic Liquids 61 Table 2: Nickel ca alyzed biphasic p opene dime iza ion eac ions in E AlCl2 bu e ed sys ems modi ied wi h he ca ionic phosphine 8.[1] [8] / [BMIMCl] P oduc i i y[2] Dime s [%] 0 > 18.1[3] 79.6 0.03 > 22.5[3] 83.6 0.06 > 13.5[3] 89.1 [1] Reac ion condi ions: 2 – 3 g bu e ed ionic liquid; [BMIMCl] / [AlCl3] / [E AlCl2] = 1.00 / 1.20 / 0.20; ca alys p ecu so 15; [ca ] = 10–5 mol / gionic liquid; T = 25°C; s i ing a e = 1200 min–1; = 45 min; 300 ml glass au ocla e; 40 – 60 ml liquid p opene. [2] gp oduc / gionic liquid x h. [3] Comple e con e sion. NMR In es iga ions Since ia ylphosphines we e e icien bu e s o Lewis acidic chlo oalumina e ionic liquids, he phospho us cen e makes hem p edes ined o 31P NMR in es iga ions. Sys ems wi h he e en mo e e ec i e BiPh3 bu e a e di icul o in es iga e by nuclea magne ic esonance expe imen s. The na u ally occu ing 209Bi iso ope displays a spin o 9/2. Fi s , a [BMIM]+[Al2Cl7]− ionic liquid was sa u a ed wi h ha dly soluble PPh3 and mixed wi h a ew d ops o C6D6 in an NMR ube. Scheme 3 shows he 31P and 27Al NMR spec a. The “bu e ing” in e ac ion can be seen clea ly om he b oad peak (line wid h a hal maximum: 560 Hz) a δ = −13 ppm in he 31P NMR spec um due o as in e molecula exchange eac ions. The PPh3 signal, which usually appea s a δ = −6 ppm, is shi ed o highe equencies due o he in e ac ion o iphenylphosphine wi h he Lewis acidic aluminum cen e s. Be ween δ = 4 − 10 ppm, ano he signal appea s, which indica es a new species. I ob iously consis s o mo e han one P nuclei and gi es an AB2 spin pa e n. The cons i u ion o his compound is no clea ye . The 27Al NMR spec um displays a line wid h a hal maximum o 2450 Hz, which is ypical o an acidic [imidazolium]+[Al2Cl7]− ionic liquid.[23] Analogously o he li e a u e, a signal wi h his line wid h a ises om [Al2Cl7]− species. These anions a e bigge han [AlCl4]− anions and possess a less symme ical su ounding o he Al cen e . Thus, he signal is b oadened by e icien nuclea quad upole elaxa ion. 5 Facile Syn hesis o new Ca ionic T iphenylphosphine De i a i es and hei Use o P opene Dime iza ion Reac ions in Bu e ed Chlo oalumina e Ionic Liquids 62 Scheme 3: 31P and 27Al NMR spec um o PPh3 in he ionic liquid [BMIM]+[Al2Cl7]− (C6D6, 25°C). A second sample consis ing o [BMIM]+[Al2Cl7]− wi h 0.30 equi alen s o he mo e basic, s e ically hinde ed i- e -bu ylphosphine was p epa ed. Su p isingly, a e he addi ion o small amoun s o C6D6, he sys em unde wen a phase sepa a ion. A clea phase (Scheme 4) sepa a ed on op o a u bid phase (Scheme 5). Upon addi ion o mo e C6D6, he phases combined again. Bo h phases we e in es iga ed by means o NMR spec oscopy. The peak a δ = 63.6 ppm belongs o excess i- e -bu ylphosphine, which does no in e ac wi h he ionic liquid.[24] Unlike using PPh3, he in e ac ion o i- e - bu ylphosphine wi h he Lewis acidic aluminum species in he ionic liquid gene a es an unusual sex e be ween δ = 22 and 32 ppm. The P–Al in e ac ion is s onge leading o a spli ing o he 31P signal by he spin 5/2 nucleus 27Al, and exchange eac ions a e slow in NMR ime scale. The di e en in ensi ies wi hin he sex e a e no mal o couplings o 1/2 spin nuclei wi h a quad upole nucleus. A simple i- e -bu ylphosphine adduc o AlCl3 in o ganic sol en s did no show a sex e [25] bu b oad signals. In oluene, he adduc s o PMe3 o PE 3 wi h AlCl3 only gene a ed a single in he 31P NMR spec um, while a double was obse ed in he 27Al NMR spec um.[26] This could be explained wi h as exchange eac ions in solu ion. In chlo oalumina e ionic liquids, he exchange a es may be educed. The π-in e ac ions o oluene p obably educed he Lewis acidi y o AlCl3 in solu ion leading o a weake dono -accep o in e ac ion wi h he phosphine. Simila ly o he PPh3 sys em abo e, he spec um shows an AB2 spin pa e n be ween δ = 56 and 60 ppm. This spin sys em mus be de i ed om a di e en phosphine species p esen in he liquid. Un o una ely, he na u e o ha species could no be de e mined 5 Facile Syn hesis o new Ca ionic T iphenylphosphine De i a i es and hei Use o P opene Dime iza ion Reac ions in Bu e ed Chlo oalumina e Ionic Liquids 63 ye . Due o as chlo ine / alkyl exchange in he eac ion mix u e, ing o chain like oligophosphines could be o med. This beha iou should be discussed in ano he pape . Scheme 4: 31P and 27Al NMR spec um o he uppe phase o he mix u e [BMIM]+[Al2Cl7]− / i- e -bu ylphosphine (0.30 equi alen s) in C6D6 (25°C). Scheme 5: 31P and 27Al NMR spec um o he bo om phase o he mix u e [BMIM]+[Al2Cl7]− / i- e -bu ylphosphine (0.30 equi alen s) in C6D6 (25°C). The spec a o bo h he uppe and he lowe phase, display he same peak pa e ns. Howe e , he concen a ions a e di e en . The P–Al in e ac ing species is en iched in he lowe phase wi h a a io o app oxima ely 83 o 17 compa ed o he unde ined species. In he uppe phase he a io is abou 55 o 45. In he 27Al NMR spec a wo sha p signals a δ = 134.6 and 132.1 ppm s ick ou o he b oad o e lying signal o [Al2Cl7]−. They belong o he co esponding Al cen e coupling wi h i- e - bu ylphosphine. The signals o a leas wo o he Al species mus be p esen in he sys em indica ed by wo shoulde s a abou 112 and 122 ppm. Fo compa ison, ano he sample was p epa ed by dissol ing he ionic phosphine 8 in a neu al [BMIM]+[AlCl4]− ionic liquid (Scheme 6). The 31P NMR signal appea s a δ = −5.7 5 Facile Syn hesis o new Ca ionic T iphenylphosphine De i a i es and hei Use o P opene Dime iza ion Reac ions in Bu e ed Chlo oalumina e Ionic Liquids 64 ppm wi h a line wid h a hal maximum o 32 Hz. These signals a e b oade han hose ob ained om 8 dissol ed in CDCl3 (2.2 Hz). The line wid h o 41 Hz in he 27Al NMR spec um also co ela es wi h a ypical line wid h o 23 Hz measu ed o neu al imidazolium based chlo oalumina e ionic liquids.[23a] Thus, he e is only li le in e ac ion o he phospho us a oms wi h he [AlCl4]− species. Scheme 6: 31P and 27Al NMR spec a o he ca ionic phosphine 8 in he ionic liquid [BMIM]+[AlCl4]− (C6D6, 25°C). Finally, h ee samples o he ca ionic phosphine 8 in [BMIM]+[Al2Cl7]− wi h concen a ions o 0.10 (Scheme 7), 0.30 and 0.50 equi alen s (Scheme 8) we e p epa ed and in es iga ed by NMR spec oscopy. In he 31P NMR spec a, he signal de i ed om he P–Al in e ac ion appea s a δ = 13.8 ppm in all h ee samples. The mul iple o he unde ined phosphine species was obse ed be ween δ = 3 and 9 ppm. Wi h inc easing phosphine con en , a shoulde de elops in he 31P NMR signal induced by addi ional iodide anions coming along wi h he addi ion o he ionic phosphine. Ou esul s showed ha weak P–Al in e ac ions a e c ucial o phosphine bu e ed Lewis acidic chlo oalumina e ionic liquid coca alys s. The s ong Lewis base i- e -bu yl- phosphine coupled wi h aluminum o gi e a double in he 27Al NMR and a sex e in he 31P NMR spec um. In con as , only b oad signals we e obse ed o ia ylphosphine bu e s. A highly dynamic sys em is ob ained om he combina ion o weakly Lewis basic ia ylphosphines in combina ion wi h Lewis acidic chlo oalumina e mel s. The as P–Al exchange is necessa y o main ain a su icien Lewis acidi y o ac i a e nickel ca- alys p ecu so as well as o supp ess uncon olled ca ionic ole in oligome iza ion eac ions. 5 Facile Syn hesis o new Ca ionic T iphenylphosphine De i a i es and hei Use o P opene Dime iza ion Reac ions in Bu e ed Chlo oalumina e Ionic Liquids 65 Scheme 7: 31P NMR spec um o 0.10 equi alen s o he ca ionic phosphine 8 in he ionic liquid [BMIM]+[Al2Cl7]− (C6D6, 25°C). Scheme 8: Exce p s o he 31P NMR spec a o he mix u es con aining 0.10 (le ), 0.30 (middle) and 0.50 ( igh ) equi alen s o he ca ionic phosphine 8 in he ionic liquid [BMIM]+[Al2Cl7]− (C6D6, 25°C). Conclusions The syn hesized ca ionic iphenylphosphine de i a i e 8 success ully bu e ed he highly Lewis acidic [BMIM]+[Al2Cl7]− ionic liquid. I s e a luo obo a e equi alen 5 was insoluble in he ionic liquid. A nickel complex could be ac i a ed wi h he bu e ed composi ion and dime ized p opene in a biphasic eac ion wi h a selec i i y o 84% o gi e dime s. Undesi ed uncon olled ca ionic ole in oligome iza ion eac ions we e p e en ed by he addi ion o 0.30 equi alen s o 8 o he ionic liquid. Adding 0.06 equi- alen s o 8 o a comme cially used DIFASOL® ionic liquid composi ion, he dime yield could be inc eased om 80% o 89%. The P–Al in e ac ion was in es iga ed by 31P and 27Al NMR spec oscopy. While no P–Al coupling be ween bu e ing ia ylphosphines and aluminum cen e s could be obse ed, he mo e basic bu s e ically hinde ed i- e - bu ylphosphine coupled wi h 27Al o gi e an expec ed bu unusual sex e in he 31P NMR spec um. The s aigh - o wa d syn hesis o he ca ionic phosphine 8 in combina ion 5 Facile Syn hesis o new Ca ionic T iphenylphosphine De i a i es and hei Use o P opene Dime iza ion Reac ions in Bu e ed Chlo oalumina e Ionic Liquids 66 wi h he high yield makes such ca ionic iphenylphosphine de i a i es in e es ing o biphasic eac ions. When iphenylphosphine is eplaced by i s ca ionic de i a i e, leaching e ec s can be minimized and ca alys li e imes should inc ease. Due o he absence o acidic p o ons, iphenylphosphines wi h qua e nized ammonium subs i uen s can also be applied when highly eac i e me al alkyl g oups like alkylaluminum bonds a e p esen . Besides dime iza ion and polyme iza ion eac ions, possible applica ions can be ound in biphasic hyd o o myla ion,[27] hyd ogena ion,[6b] o c oss coupling eac ions.[4] 5.3 Expe imen al Sec ion Gene al Rema ks All chemical manipula ions we e ca ied ou using s anda d Schlenk echniques unde a gon a mosphe e. THF was dis illed om Na/K alloy. CH2Cl2 was dis illed in wo s eps om P4O10 and CaH2. Fo d ying me hanol, magnesium u nings we e dissol ed in he sol en be o e dis illa ion. Demine alized wa e was degassed wi h a gon p io o use. Ace oni ile (Ac os, p.a.) was used as ecei ed. 1H, 11B, 13C, 27Al and 31P NMR spec a we e eco ded on Va ian Ino a 300 MHz o 400 MHz spec ome e s. Chemical shi s a e gi en ela i e o Me4Si: δ 1H (CHCl3) = 7.24 ppm; δ 1H (CD3(SO)CD2H) = 2.50 ppm; δ 13C (CDCl3) = 77.2 ppm; δ 13C (CD3(SO)CD3) = 39.5 ppm; ex e nal 85% H3PO4 [δ 31P = 0 ppm o Ξ (31P) = 40.480747 MHz]; ex e nal 1.1 M Al(NO3)3 in D2O [δ 27Al = 0 ppm o Ξ (27Al) = 26.056890 MHz]; ex e nal BF3-OE 2 [δ 11B = 0 ppm o Ξ (11B) = 32.083971 MHz]. Chemical shi s a e gi en o ± 0.1 ppm in 13C and 31P NMR spec a and ± 0.4 ppm in 11B and 27Al NMR spec a. The p oduc s o he dime iza ion expe imen s we e cha ac e ized by gas ch oma og aphy (Agilen 6850). GC-MS spec a we e measu ed on a The mo Scien i ic FOCUS DSQ™. Mass spec a we e eco ded on a Va ian MAT CH7 ins umen (di ec inle sys em, elec on impac ioniza ion 70 eV). Elemen al analyses we e pe o med wi h a Va ioEl III CHN ins umen . Ace anilide was used as a s anda d. P opene (99.3%) was pu chased om Riessne Gase, Lich en els, and was d ied o e a column packed wi h P4O10. E AlCl2 (0.9 M in hep ane) and i- e -bu yl- phosphine (95%) we e pu chased om Ac os and used wi hou u he pu i ica ion. Compound 11 was syn hesized acco ding o he li e a u e.[4a] T iphenylamine, iphenyl- 5 Facile Syn hesis o new Ca ionic T iphenylphosphine De i a i es and hei Use o P opene Dime iza ion Reac ions in Bu e ed Chlo oalumina e Ionic Liquids 67 phosphine, iphenylbismu h, is(p-chlo ophenyl)phosphine, and is(m-chlo ophenyl)- phosphine we e pu chased om ABCR. 1-Bu yl-3-me hylimidazolium chlo ide, dicyclo- hexylamin, ichlo osilane, p-(dime hylamino)phenyldiphenylphosphine, he bo ane- e ahyd o u ane complex, AlCl3 (Reagen Plus®), and compound 13 we e pu chased om Sigma-Ald ich and used wi hou u he pu i ica ion. Diphenylphosphino e ocene was ob ained om MCAT. Syn hesis o he Ionic Liquids The ionic liquids we e syn hesized by di ec ly mixing he co esponding amoun s o AlCl3 and chlo ide sal in a cooled Schlenk ube. In he case o E AlCl2 con aining sys ems, a 0.9 mola solu ion o E AlCl2 in hep ane was added o he liquid, and he sol en was emo ed in acuo. The ob ained ionic liquids we e s o ed in Schlenk ubes. P ocedu e o he Dime iza ion Reac ions using Bu e ed Ionic Liquids P io o he expe imen s, abou 2 ml o he ionic liquid we e illed in o a Schlenk ube and mixed wi h he bu e . A e he bu e had dissol ed upon s i ing, he nickel com- plex 15 was added. The ob ained homogeneous solu ion was sy inged in o he eac ion essel. I s amoun was de e mined by he weigh di e ence o he sy inge. In he case o pa ly soluble bu e s, he mix u e was s i ed un il he solid was dis ibu ed homo- geneously in he liquid. Then, he slu y was sy inged in o he eac ion essel. Fo all dime iza ion expe imen s, a 300 ml glass au ocla e equipped wi h a s i ing ba and a magne ic s i e wi h a s i ing a e o 1200 min–1 was used. The glass au ocla e was kep in a d ying o en a 150°C o se e al hou s be o e an expe imen . A e addi ion o he ac i e ionic liquid, p opene (40 o 60 ml) was condensed in o he glass au ocla e by liquid ni ogen cooling. Then, he au ocla e was placed in a me al box o sa e y easons, and he empe a u e was egula ed by an ex e nal wa e ba h. A e he expe imen , he p essu e was slowly eleased by opening a al e. The p oduc ac ion was il e ed h ough a sho plug o silica and analyzed by gas ch oma og aphy. Syn hesis o [4-(T ime hylammonium)phenyldiphenylphosphine Oxide] Iodide 3 Hyd ogen pe oxide (5.0 g, 30% in H2O) was slowly added o a solu ion o 1 (11.11 g, 36.38 mmol) in CH2Cl2 (100 ml). The mix u e was s i ed o 30 minu es and e apo a ed o d yness. The c ude phosphine oxide 2 was dissol ed in CH2Cl2 (100 ml) ollowed by 6 Nickel Ca alyzed P opene Dime iza ion Reac ions in BiPh3 Bu e ed Chlo oalumina e Ionic Liquids: High Pe o mance wi h Uncon en ional Ca ions 74 he composi ion. A lowe eac ion empe a u es, he selec i i ies o gi e dime s inc eased signi ican ly. P opene dime s we e ob ained wi h selec i i ies o up o 98%. A ca ion sc eening wi h 100 ammonium and phosphonium halide sal s was pe o med. N- Me hylpy olidine hyd ochlo ide ga e he bes esul s in e ms o selec i i y and li e ime. P opene dime iza ion eac ions in BiPh3 bu e ed chlo oalumina e mel s we e ca alyzed by a ious soluble nickel compounds wi h simila pe o mances. The in oduc ion o basic, s e ically demanding icyclohexylphosphine ligands led o highe deg ees o b anching, howe e , a he expense o lowe dime selec i i ies. 6.1 In oduc ion Selec i e dime iza ion eac ions o α-ole ins a ac ed a lo o a en ion in he second hal o he 20 h cen u y, a e Ziegle desc ibed he “nickel e ec ” in 1955.[1] Nickel impu i ies om p e ious hyd ogena ion eac ions we e ound o ca alyze selec i e e hene dime iza ion eac ions o gi e bu enes in he p esence o alkylaluminum compounds. Ziegle was o iginally in e es ed in chain g ow h and polyme iza ion eac ions. Howe e , his disco e y also launched an in ensi e esea ch on selec i e nickel ca alyzed dime iza ion eac ions o sho chain ole ins in he ollowing decades.[2] The DIMERSOL® p ocess o he Ins i u F ançais du Pé ole (IFP) is he la ges indus ial p ocess based on nickel complexes ac i a ed by alkylaluminum coca alys s. I was de eloped by Chau in e al. in he 1970s[3] o dime ize p opene (DIMERSOL® G) o 1-bu ene (DIMERSOL® X) selec i ely. Cu en ly, 35 licensed DIMERSOL® uni s wi h ypical capaci ies be ween 20000 and 90000 ons pe yea a e in use o selec i e dime iza ion eac ions o sho chain ole ins.[4] Abou 30 yea s ago, Wilkes e al. and Os e young e al. epo ed he i s oom empe a u e ionic liquids based on aluminum chlo ide.[5] In he 1980s, hese chlo o- alumina e ionic liquids we e ho oughly in es iga ed in e ms o hei physical and elec ochemical p ope ies.[6] I ook abou en mo e yea s un il chlo oalumina e ionic liquids s a ed o a ac a en ion as new media o biphasic ca alysis.[7] Ini ially, Lewis acidic chlo oalumina e mel s we e used as ca alys s o F iedel C a s alkyla ion eac ions.[8] In he 1990s, Chau in e al. de eloped nickel ca alyzed biphasic 6 Nickel Ca alyzed P opene Dime iza ion Reac ions in BiPh3 Bu e ed Chlo oalumina e Ionic Liquids: High Pe o mance wi h Uncon en ional Ca ions 75 dime iza ion eac ions o α-ole ins in o ganochlo oalumina e ionic liquids.[9] E hylalumi- num g oups we e ound o supp ess uncon olled ca ionic ole in oligome iza ion eac ions, which occu in solely AlCl3 based ionic liquids.[10] The IFP b ough his so called DIFASOL® p ocess o indus ial applica ion by e o i ing i o hei exis ing DIMERSOL® uni s.[4a, 11] Besides alkylaluminum g oups, he addi ion o weak Lewis bases also educes he “la en acidi y”[12] o chlo oalumina e mel s. While Wasse scheid e al. used py ole, py idine, and quinoline de i a i es o p e en undesi ed ca ionic ole in oligome iza ion eac ions,[13] we ecen ly epo ed ha iphenylphosphine and iphenylbismu h e icien ly bu e e en highly acidic chlo oalumina e ionic liquids.[14] These bu e ed chlo oalumina e mel s we e success ully employed o ac i a e nickel complexes o selec i e p opene dime iza ion eac ions. Bu e ing wi h Lewis base addi i es is ad an ageous compa ed o he comme cial DIFASOL® sys em. Fi s , bu e ing wi h E AlCl2 is es ic ed o only sligh ly acidic composi ions. I highe acidi ies a e chosen, he dime selec i i ies dec ease. Second, a highe alkylaluminum con en s, leaching o neu al chlo oalkylaluminum compounds o med by disp opo iona ion eac ions[15] becomes a majo p oblem.[11b] Also, alkylaluminum coca alys s con ibu e o he deac i a ion o Ni(II) ca alys s by educing Ni(II) o i s ze o oxida ion s a e.[16] Usually, he mel ing poin s o aluminum chlo ide based ionic liquids display a minimum o highly acidic mel s, while a local maximum is obse ed a ound equimola composi ions.[6a, 17] The e o e, DIFASOL® sys ems a e limi ed o ca ions in insically o ming low mel ing liquids, e.g. N,N’-alkylme hyl- imidazolium o N-alkylpy idinium sal s.[13b] In a ecen pape , we desc ibed ha he mel ing poin s o acidic chlo oalumina e sys ems a e educed upon addi ion o BiPh3. Thus, i was possible o ob ain bu e ed oom empe a u e ionic liquid composi ions om aluminum chlo ide and ca ions, which would only yield solids a ambien empe a u e wi hou BiPh3.[14a] Fu he mo e, he scope o po en ial ca ions became e en la ge since low mel ing highly acidic sys ems could be used o nickel ca alyzed selec i e ole in dime iza ion eac ions. Because no eac i e alkylaluminum g oups we e p esen in BiPh3 bu e ed chlo oalumina e ionic liquids, hese sys ems we e no limi ed o qua e na y ammonium ca ions. Ins ead, 6 Nickel Ca alyzed P opene Dime iza ion Reac ions in BiPh3 Bu e ed Chlo oalumina e Ionic Liquids: High Pe o mance wi h Uncon en ional Ca ions 76 cheap halide sal s like amine hyd ochlo ides could be used, which can be eco e ed easily upon hyd olysis. In his pape , we epo nickel ca alyzed p opene dime iza ion eac ions in BiPh3 bu e ed chlo oalumina e mel s wi h 100 mos ly uncon en ional ca ion composi ions. Only wo ou o 100 mix u es did no o m liquids a ambien empe a u e. Fu he mo e, he e ec o Lewis acidi ies, bu e con en s and eac ion empe a u es on he dime selec i i ies was in es iga ed. Finally, se e al nickel complexes we e es ed o hei pe o mances in BiPh3 bu e ed chlo oalumina e mel s. 6.2 Resul s and Discussion Va ia ion o Bu e ing and Acidi y Le els As desc ibed in ou ecen pape , no only sligh ly acidic chlo oalumina e mel s could be bu e ed wi h BiPh3 bu also highly acidic [ca ion]+[Al2Cl7]− sys ems.[14a] The e o e, he e ec o di e en acidi ies and BiPh3 con en s in chlo oalumina e ionic liquids on nickel ca alyzed p opene dime iza ion eac ions was in es iga ed in de ail (Table 1). Fo he sc eening expe imen s, we used ou s anda d nickel complex A as he ca alys p ecu so (Figu e 1). Figu e 1: Ca alys p ecu so used o biphasic p opene dime iza ion eac ions. We chose a sys em based on he comme cially a ailable 1-bu yl-3-me hylimidazolium (BMIM) e achlo oalumina e, o which he co esponding amoun s o AlCl3 we e added. Wi h sligh ly acidic AlCl3 / BMIMCl = 1.20 sys ems, which we e used by Wasse scheid e al.[13b] and o DIFASOL® sys ems[9c], dime s we e ob ained s a ing wi h 0.07 6 Nickel Ca alyzed P opene Dime iza ion Reac ions in BiPh3 Bu e ed Chlo oalumina e Ionic Liquids: High Pe o mance wi h Uncon en ional Ca ions 77 equi alen s o BiPh3 (2). Wi h inc easing bu e con en , selec i i ies inc eased. Employing 0.30 equi alen s o BiPh3, al eady 96% dime s we e ob ained (4), howe e , a he expense o a educed p oduc i i y. Table 1: Nickel ca alyzed p opene dime iza ion eac ions in BiPh3 bu e ed chlo o- alumina e mel s wi h di e en composi ions.[1] No. [AlCl3] / [BMIMCl] [BiPh3] / [BMIMCl] P oduc i i y[2] C6 [%] 1 1.20 0.05 > 15.8[3] Oil[4] 2 1.20 0.07 > 10.8[3] 89.2 3 1.20 0.12 > 8.0[3] 93.1 4 1.20 0.30 6.7 96.0 5 1.30 0.12 > 8.0[3] 81.8 6 1.50 0.12 > 10.6[3] 74.1 7 1.50 0.18 > 12.0[3] 83.2 8 2.00 0.12 > 11.4[3] 74.8 9 2.00 0.18 > 12.3[3] 79.5 10 2.00 0.24 > 7.4[3] 83.3 11 2.00 0.30 > 9.3[3] 85.5 12 2.00 0.60 > 11.5[3] 90.6 [1] Reac ion condi ions: 2.5 – 3.5 g bu e ed ionic liquid; ca alys p ecu so A; [ca ] = 10–5 mol / gionic liquid; T = 25°C; s i ing a e = 1200 min–1; = 60 min; 300 ml glass au ocla e; 40 – 70 ml liquid p opene. [2] gp oduc / gionic liquid x h. [3] Comple e con e sion. [4] Highe oligome s de i ed om a ca ionic oligome iza ion eac ion. Due o mass ans e limi a ions,[13d] he e m “ac i i y” was eplaced by “p oduc i i y”. Thus, abo e a ca alys concen a ion o abou 10–6 mol / gionic liquid,[14a] he p oduc yield pe hou is p opo ional o he amoun o ionic liquid and independen om he ca alys 6 Nickel Ca alyzed P opene Dime iza ion Reac ions in BiPh3 Bu e ed Chlo oalumina e Ionic Liquids: High Pe o mance wi h Uncon en ional Ca ions 78 concen a ion. As expec ed, inc easing acidi ies wi h a cons an bu e le el educed he dime selec i i ies. Howe e , om an AlCl3 / BMIMCl a io o 1.50 o 2.00, he selec i i ies d opped only a ew pe cen i he bu e le el was held cons an . Thus, he ad an age o low mel ing poin s a highly acidic composi ions did no ha e o be paid by disp opo ional high amoun s o bu e . Wi h only 0.12 equi alen s o bu e , he maximum acidic sys em s ill yielded abou 75% dime s (8). Ca ion Sc eening Conside ing hese esul s, we we e cu ious i ou sys em can be ex ended o a he unusual and cheap ca ions. In he li e a u e, only a ew chlo oalumina e sys ems we e men ioned, which did no ely on s anda d imidazolium o py idinium ca ions. T ime hylammonium hep achlo odialumina e was used o ca ionic oligome iza ion eac ions o 1-decene.[18] The use o ie hylamine hyd ochlo ide, dibu ylamine hyd ochlo ide, e hylamine hyd ochlo ide, and dime hylamine hyd ochlo ide was epo ed o F iedel C a s alkyla ion eac ions.[7e] Dime hylaniline hyd ochlo ide,[19] and se e al qua e na y asymme ic benzyl subs i u ed mel s we e desc ibed, oo.[20] Howe e , none o hese we e used o nickel ca alyzed ole in dime iza ion eac ions due o he abo e men ioned mel ing poin and acidi y es ic ions. F iedel C a s alkyla ion eac ions o ca ionic ole in oligome iza ion eac ions employ he Lewis acidic ionic liquid i sel as ca alys . Thus, in hese cases a a ia ion o he ca ion should only esul in mino changes on he esul s o he eac ions. In con as , he pe o mances o nickel ca alyzed ole in dime iza ion eac ions in BiPh3 bu e ed chlo oalumina e mel s should s ongly depend on he ca ion. The eac ions a e ca alyzed by a nickel complex, no by he ionic liquid i sel . I is necessa y ha he BiPh3 bu e dissol es well in he ionic liquids o minimize leaching e ec s. Also, he ca ion de e mines he iscosi ies and he solubili ies o he subs a e ole in wi hin he ionic liquids. Bo h he iscosi y and he solubili y o he subs a e a e c ucial since biphasic nickel ca alyzed dime iza ion eac ions in chlo oalumina e mel s su e om a mass anspo limi a ion o he ole in.[13d] The e o e, we decided o pe o m a sys ema ic sc eening o ca ions including qua e na y ammonium sal s, hyd ochlo ides o p ima y, seconda y and e ia y amines, phosphonium sal s, he e ocyclic ammonium sal s, and ca ions wi h mo e han one he e oa om. One hund ed di e en halide sal s and hei AlCl3 / halide sal = 2.00 composi ions we e syn hesized. These composi ions we e bu e ed wi h 0.30 6 Nickel Ca alyzed P opene Dime iza ion Reac ions in BiPh3 Bu e ed Chlo oalumina e Ionic Liquids: High Pe o mance wi h Uncon en ional Ca ions 79 equi alen s o BiPh3 and es ed o nickel ca alyzed p opene dime iza ion eac ions. The sc eening eac ions we e pe o med in ba ch expe imen s. Fu he mo e, he li e ime o each sys em was in es iga ed quali a i ely. A e each expe imen , he p oduc phase was decan ed un il he dime selec i i y d opped signi ican ly. In Table 2, 33 selec ed ca ions and he co esponding C6 selec i i ies ob ained in he i s ba ch expe imen a e shown. The comple e da ase can be ound in he Suppo ing In o ma ion. Since he e e ence complex A had no e ec on he b anching o he hexene dime s,[14a] all C6 ac ions consis ed o (± 2%) 25% n-hexenes, 69% 2-me hylpen enes, and 6% 2,3-dime hylbu enes. This co ela ed o he ypical p oduc dis ibu ion ob ained om ligand ee nickel sal s.[13d] Because he p oduc i i ies o such bu e ed sys ems mainly depended on he bu e ing le el,[14a] he p oduc i i ies o di e en ca ions should no be compa ed di ec ly. Ca ions yielding composi ions wi h a good BiPh3 e iciency au oma ically displayed highe dime selec i i ies and subsequen ly lowe p oduc i i ies. The e o e, he goal was o iden i y sys ems, which kep high selec i i ies o e many epe i ions. Su p isingly, 95 o 100 composi ions p oduced dime s. Only wo ca ions, o mamidine hyd ochlo ide and 1,4-diazabicyclo[2.2.2]oc ane hyd ochlo ide, yielded solids a ambien empe a u e (see Suppo ing In o ma ion). E en he pen a alen iphenylphosphine dichlo ide based sys em (45) success ully dime ized p opene o gi e 50% dime s (45). Howe e , he sys ems displayed big di e ences in hei o e all pe o mances. The bes esul s we e ob ained wi h qua e na y ammonium sal s and hyd ochlo ides o e ia y amines. In gene al, hyd ochlo ides o p ima y and seconda y amines we e less selec i e. Howe e , e en small changes on he ca ion could ha e se e e e ec s on he li e imes and selec i i ies o he sys ems. Fo example, he 1-bu yl-3-me hylimidazolium chlo ide ca ion, which was used o he ini ial acidi y sc eening expe imen s, was ound among he wo s qua e na y ammonium ca ions (22). In oduc ion o an e hyl (17) ins ead he bu yl chain signi ican ly imp o ed he selec i i y as well as he li e ime o he sys em (see Suppo ing In o ma ion). As al eady epo ed, he sys em based on N- me hylpy olidine hyd ochlo ide (26) displayed he bes pe o mance in e ms o selec i i y and quali a i e li e ime.[14a] In he case o he BiPh3 bu e , he e appea s o be an op imum ange o ca bon a oms o ammonium sal s, oughly be ween i e and nine. Ionic liquids de i ed om ca ions wi h mo e o less ca bon a oms d opped much as e in e ms o selec i i y han hose wi hin ha ange. 6 Nickel Ca alyzed P opene Dime iza ion Reac ions in BiPh3 Bu e ed Chlo oalumina e Ionic Liquids: High Pe o mance wi h Uncon en ional Ca ions 80 Table 2: Selec ed esul s o he ca ion sc eening o nickel ca alyzed p opene dime i- za ion eac ions in BiPh3 bu e ed chlo oalumina e mel s (le : qua e na y ammonium chlo ide sal s; middle: hyd ochlo ides o e ia y amines; igh : hyd ochlo ides o p ima y and seconda y amines and phosphonium sal s).[1] No. Ca ion C6 [%] No. Ca ion C6 [%] No. Ca ion C6 [%] 13 92.0 24 93.1 35 90.4 14 91.2 25 92.5 36 83.0 15 90.9 26 91.6 37 79.0 16 90.1 27 90.7 38 76.1 17 90.0 28 90.0 39 73.3 18 89.7 29 89.9 40 66.1 19 89.3 30 89.6 41 92.5 20 89.3 31 89.6 42 91.0 21 89.2 32 89.6 43 85.4 22 86.2 33 89.4 44 68.6 23 75.9 34 89.1 45 49.5 [1] Reac ion condi ions: 2.5 – 4.0 g bu e ed ionic liquid; composi ion [BiPh3] / [ca ion]+[Al2Cl7]− = 0.30; ca alys p ecu so A; [ca ] = 10–5 mol / gionic liquid; T = 25°C; s i ing a e = 1200 min–1; = 60 min; 300 ml glass au ocla e; 40 – 60 ml liquid p opene. 6 Nickel Ca alyzed P opene Dime iza ion Reac ions in BiPh3 Bu e ed Chlo oalumina e Ionic Liquids: High Pe o mance wi h Uncon en ional Ca ions 81 Tempe a u e E ec on Dime Selec i i ies Fu he , we in es iga ed he e ec o he eac ion empe a u e on dime selec i i ies wi h 0.30 and 0.60 equi alen s o BiPh3 (Table 3). The eac ions we e pe o med ei he a ambien empe a u e o a 0°C. Table 3: Nickel ca alyzed p opene dime iza ion eac ions in BiPh3 bu e ed chlo o- alumina e mel s a 0°C and 25°C.[1] Ca ion No. [Bu e ] / [Ca ion] Tempe a u e [°C] P oduc i i y[2] C6 [%] 46 0.30 25 > 10.1[3] 90.7 47 0.30 0 > 6.7[3] 95.5 48 0.60 25 4.6 93.8 49 0.60 0 – [4] – 50 0.30 25 > 10.6[3] 89.4 51 0.30 0 > 12.9[3] 96.0 52 0.60 25 > 7.6[3] 90.8 53 0.60 0 1.8 98.0 [1] Reac ion condi ions: 3.2 – 5.2 g bu e ed ionic liquid; composi ion [BiPh3] / [ca ion]+[Al2Cl7]− = 0.30; ca alys p ecu so A; [ca ] = 10–5 mol / gionic liquid; s i ing a e = 1200 min–1; = 60 min o T = 25°C; = 120 min o T = 0°C; 300 ml glass au ocla e; 40 – 60 ml liquid p opene. [2] gp oduc / gionic liquid x h. [3] Comple e con e sion. [4] Composi ion solid a 0°C. While he selec i i y o an e hyldiisop opylamine (Hunig’s base) hyd ochlo ide based sys em wi h 0.30 equi alen s o BiPh3 inc eased om 91% a 25°C (46) o 96% a 0°C (47) he mix u e con aining 0.60 equi alen s o BiPh3 solidi ied a 0°C (49). Thus, he se ies was epea ed wi h ibu ylamine hyd ochlo ide. By lowe ing he empe a u e o 0°C, he dime selec i i y could be inc eased by 7% o 96% (51) and 98% (53), espec i ely. The expe imen s also showed ha abo e a ce ain bu e concen a ion, he addi ion o mo e BiPh3 only esul ed in mino imp o emen s o he dime selec i i y. 6 Nickel Ca alyzed P opene Dime iza ion Reac ions in BiPh3 Bu e ed Chlo oalumina e Ionic Liquids: High Pe o mance wi h Uncon en ional Ca ions 82 Thus, a ca ion sc eening was manda o y o iden i y halide sal s, which display high li e imes combined wi h high selec i i ies. E ec o Di e en Nickel Ca alys P ecu so s on Dime Selec i i ies So a , only ca alys p ecu so A was used as a e e ence in all sc eening expe imen s. Now, a se ies o ypical nickel(II) halides and complexes was es ed o hei pe o mances in combina ion wi h BiPh3 bu e ed chlo oalumina e mel s (Table 4). Conside ing he esul s o ou p e ious ca ion sc eening, N-me hylpy olidine hyd o- chlo ide mixed wi h wo equi alen s o aluminum chlo ide and bu e ed wi h 0.30 equi alen s o BiPh3 was chosen as e e ence sys em. Since p opene dime iza ion eac ions in bu e ed chlo oalumina e mel s a e limi ed by mass ans e o he ole in,[13d] he p oduc i i ies o all nickel compounds should be he same i a su icien ly high ca alys concen a ion was chosen. In a ecen pape , we de e mined he minimum ca alys concen a ion necessa y o exclude ca alys concen- a ion es ic ions o be a ound 10–6 molNi / gionic liquid.[14a] We applied a concen a ion o 10–5 molNi / gionic liquid o ensu e ha he ca alys concen a ion was no he a e de e mining ac o . Fi s , he ou bina y nickel halides we e es ed. All o hem yielded e y high selec i i ies o mo e han 90%. Howe e , he p oduc i i ies we e qui e di e en . Nickel luo ide p oduced 24.9 g p oduc pe g am bu e ed ionic liquid (54). The o he halides displayed lowe p oduc i i ies. This beha iou migh be explained by he low solubili y o hese ligand ee halide sal s. Al hough 10–5 molNi / gionic liquid we e added o he liquid, he sal s did no dissol e comple ely. Nickel chlo ide seemed o be almos insoluble in he bu e ed liquid. The b omide and iodide sal s did no dissol e e y well, oo. Thus, he amoun o ca alys , which had ac ually dissol ed in he ionic liquid, migh ha e been below 10–6 molNi / gionic liquid. In his case, no only he mass ans e o he ole in bu also he ca alys concen a ion de e mined he p oduc i i y. To p o e his heo y, he iphenylphosphine adduc s o nickel chlo ide and nickel b omide we e es ed, oo (58, 59). Indeed, bo h complexes eadily dissol ed in he ionic liquid and yielded almos he same p oduc i i y o a ound 28 gp oduc / gionic liquid x h wi h a selec i i y a ound 91% o gi e C6. The p oduc i i ies o nickel hexa luo oace ylace ona e (60) and bis-(N-isop opylsalicylaldimine)-nickel(II) (61) we e only sligh ly lowe . 6 Nickel Ca alyzed P opene Dime iza ion Reac ions in BiPh3 Bu e ed Chlo oalumina e Ionic Liquids: High Pe o mance wi h Uncon en ional Ca ions 83 The composi ions o all C6 ac ions we e consis en wi h ligand ee nickel sal s. Hyd ogena ion showed ha he hexenes consis ed o 25% n-hexenes, 69% 2- me hylpen enes, and 6% 2,3-dime hylbu enes (± 2%). Ei he , he iphenylphosphine ligands we e abs ac ed om he Lewis acidic ionic liquids, o hey did no in luence he deg ee o b anching. Table 4: Ca alys sc eening o nickel ca alyzed p opene dime iza ion eac ions in BiPh3 bu e ed chlo oalumina e mel s.[1] No. Ca alys P ecu so C6 [%] Con e sion [%] P oduc i i y[2] 54 NiF2 90.9 69 24.9 55 NiCl2 95.4 7 2.5 56 NiB 2 92.6 43 14.7 57 NiI2 93.0 47 16.1 58 (PPh3)2NiCl2 90.8 80 28.8 59 (PPh3)2NiB 2 91.0 81 28.2 60 Ni(h acac)2 91.8 75 23.1 61 NiL2[3] 90.6 75 27.0 [1] Reac ion condi ions: 4.4 g bu e ed ionic liquid; composi ion [BiPh3] / [N-me hylpy olidinium]+[Al2Cl7]− = 0.30; [ca ] = 10–5 mol / gionic liquid; T = 40°C; s i ing a e = 600 min–1; = 60 min; s i ed 300 ml Pa s ainless s eel au ocla e; 130 – 160 g liquid p opene; h acac = hexa luo oace ylace ona e. [2] gp oduc / gionic liquid x h. [3] NiL2 = bis-(N-isop opylsalicylaldimine)-Ni(II)). E ec o T icyclohexylphosphine Ligands on he Dime S uc u e Finally, nickel chlo ide complexed by wo s e ically demanding icyclohexylphosphine ligands was employed as ca alys p ecu so o ole in dime iza ion eac ions in BiPh3 bu e ed chlo oalumina e ionic liquids (Table 5). S e ically hinde ed phosphines bound o a ca aly ically ac i e nickel cen e in p opene dime iza ion eac ions a e known o a ou he o ma ion o highly b anched dime s.[2c, 2e, 2 ] Especially 2,3-dime hylbu enes 6 Nickel Ca alyzed P opene Dime iza ion Reac ions in BiPh3 Bu e ed Chlo oalumina e Ionic Liquids: High Pe o mance wi h Uncon en ional Ca ions 90 (24), me hyl ibu ylammonium chlo ide (27), me hyl ioc ylammonium chlo ide (34), e ame hylammonium chlo ide (35), and N,N-dime hylme hyleneiminium chlo ide (36) we e pu chased om Sigma-Ald ich. 1-E hyl-3-me hylimidazolium chlo ide (17), ime hylphenylammonium chlo ide (19), hexame hylguanidinium chlo ide (29), and dichlo ome hylene-dime hyliminium chlo ide (32) we e pu chased om Ac os. Chlo oe hane (Chlo ae hyl, D . Henning) was pu chased in a local pha macy. The ee amine p ecu so s and haloalkanes used o syn hesize he ca ions desc ibed below we e pu chased om Sigma-Ald ich, Ac os, o ABCR. N-Benzylpy idinium chlo ide (2), 1-benzyl-3-me hylimidazolium chlo ide (8), N-benzyl-N- me hylpy olidinium chlo ide (10), ibu ylbenzylammonium chlo ide (14), dime hylcyclo- hexylbenzylammonium chlo ide (20), dime hyldibenzylammonium chlo ide (25), and dime hyle hylbenzylammonium (26) chlo ide we e syn hesized ollowing he li e a u e p ocedu e o 1-benzyl-3-me hylimidazolium chlo ide (8).[3] T ime hyle hylammonium chlo ide (15), N,N-dime hylpy olidinium chlo ide (16), ime- hylcyclohexylammonium chlo ide (23), N-me hylpy idinium chlo ide (28), and N,N-dime- hylpipe idinium chlo ide (30) we e ob ained in a one s ep eac ion by chlo ome hyla ion o he co esponding e ia y amines wi h me hylchlo o o ma e in almos quan i a i e yield applying li e a u e p ocedu es.[4] N-P opyl-N-me hylpy olidinium chlo ide (4), N-bu yl-N-me hylpy olidinium chlo ide (9), N-hexyl-N-me hylpy olidinium chlo ide (18), and N-bu yl-N-me hylpipe idinium chlo ide (7) we e syn hesized ollowing he li e a u e p ocedu e o N-bu yl-N-me hylpy olidinium chlo ide (9).[5] N-E hyl-N-me hylpy olidinium (3) chlo ide and dime hyle hylcyclohexylammonium chlo ide (12) we e ob ained as whi e p ecipi a es om eac ions o he co esponding amines wi h h ee equi alen s o chlo oe hane in oluene a 70°C. The eac ions we e pe o med in a p essu e Schlenk ube wi h a eac ion ime o en days. 6-Azoniaspi o[5.5]undecane b omide[6] (33), 5-azoniaspi o[4.4]nonane b omide[6] (21), dime hyle hylphenylammonium b omide[7] (26), 1,4-bis(3-me hylimidazolium-1-yl)bu ane chlo ide[8] (13), dime hylbenzylphenylammonium chlo ide[9] (37), and N-bu ylpy idinium chlo ide[10] (22) we e syn hesized ollowing li e a u e p ocedu es. 6 Nickel Ca alyzed P opene Dime iza ion Reac ions in BiPh3 Bu e ed Chlo oalumina e Ionic Liquids: High Pe o mance wi h Uncon en ional Ca ions 91 Hyd ochlo ides o P ima y and Seconda y Amines E hylamine hyd ochlo ide (40), dime hylamine hyd ochlo ide (42), ace amidine hyd ochlo ide (44), benzylamine hyd ochlo ide (45), me hylamine hyd ochlo ide (48), aniline hyd ochlo ide (49), and o mamidine hyd ochlo ide (51) we e pu chased om Sigma-Ald ich. Guanidine hyd ochlo ide (50) was pu chased om ABCR. The ee amine p ecu so s used o syn hesize he ca ions desc ibed below we e pu chased om Sigma-Ald ich, Ac os, o ABCR. Dicyclohexylamine hyd ochlo ide (38), py olidine hyd ochlo ide (39), cyclohexylamine hyd ochlo ide (41), dibenzylamine hyd ochlo ide (43), me hylbenzylamine hyd ochlo ide (46), and N,N,N′,N′- e ame hylguanidine hyd ochlo ide (47) we e syn hesized by slowly adding concen a ed aqueous hyd ochlo ic acid o a cooled lask con aining he co esponding amines. Op ionally, se e al hyd ochlo ides could be p ecipi a ed by he addi ion o isop opanol o ace one o he concen a ed aqueous solu ion. All o he compounds we e ob ained by acuum d ying o he aqueous solu ion a ele a ed empe a u es. Hyd ochlo ides o Te ia y Amines 1-(2-Chlo oe hyl)pipe idine hyd ochlo ide (53), ie hylamine hyd ochlo ide (57), ime hylamine hyd ochlo ide (71), 1-me hylimidazolium chlo ide (86), imidazole hyd o- chlo ide (88), and py idine hyd ochlo ide (91) we e pu chased om Sigma-Ald ich. The comme cially a ailable amine p ecu so s and haloalkanes used o syn hesize he ca ions desc ibed below we e pu chased om Sigma-Ald ich, Ac os, o ABCR. N-P opylpy olidine, N-isop opylpy olidine, N-nbu ylpy olidine, N- e -bu ylpy olidine, N-cyclohexylpy olidine, and N-p opylpipe idine we e ob ained om he co esponding p ima y amines and dib omoalkanes applying he li e a u e p ocedu e desc ibed o N- e -bu ylpy olidine.[11] N,N-Dime hyl-1-cyclopen en-1-amine was syn hesized acco ding o he li e a u e.[12] N-Me hylpy olidine hyd ochlo ide (61), N-e hylpy olidine hyd ochlo ide (70), N-p opyl- py olidine hyd ochlo ide (75), N-isop opylpy olidine hyd ochlo ide (65), N-nbu yl- py olidine hyd ochlo ide (78), N- e -bu ylpy olidine hyd ochlo ide (52), N-cyclohexyl- py olidine hyd ochlo ide (85), N-me hylpipe idine hyd ochlo ide (69), N-e hylpipe idine hyd ochlo ide (77), N-p opylpipe idine hyd ochlo ide (60), N-cyclohexylpipe idine hyd o- 6 Nickel Ca alyzed P opene Dime iza ion Reac ions in BiPh3 Bu e ed Chlo oalumina e Ionic Liquids: High Pe o mance wi h Uncon en ional Ca ions 92 chlo ide (81), dime hyle hylamine hyd ochlo ide (68), me hyldie hylamine hyd ochlo ide (55), dime hylisop opylamine hyd ochlo ide (56), e hyldiisop opylamine hyd ochlo ide (64), ibu ylamine hyd ochlo ide (76), iisobu ylamine hyd ochlo ide (63), iisopen yl- amine hyd ochlo ide (79), ioc ylamine hyd ochlo ide (59), dime hylcyclohexylamine hyd ochlo ide (83), die hylcyclohexylamine hyd ochlo ide (80), me hyldicyclohexylamine hyd ochlo ide (82), e hyldicyclohexylamine hyd ochlo ide (73), dime hylbenzylamine hyd ochlo ide (84), ibenzylamine hyd ochlo ide (89), 1,2,2,6,6-pen ame hylpipe idine hyd ochlo ide (87), and 1,4-diazabicyclo[2.2.2]oc ane hyd ochlo ide (92) we e syn hesized by slowly adding concen a ed aqueous hyd ochlo ic acid o a cooled lask con aining he co esponding amines. Op ionally, se e al hyd ochlo ides could be p ecipi a ed by he addi ion o isop opanol o ace one o he concen a ed aqueous solu ion. All o he compounds we e ob ained by acuum d ying o he aqueous solu ion a ele a ed empe a u es. 2-Me hyl-1-py oline hyd ochlo ide (66), 1-py olidino-1-cyclopen ene hyd ochlo ide (67), 1-pipe idino-1-cyclohexene hyd ochlo ide (74), N,N-dime hyl-1-cyclopen en-1- amine hyd ochlo ide (72), and N,N-dime hylaniline hyd ochlo ide (90) could no be ob ained as solids om aqueous solu ion and we e p epa ed om hei ee amines and HCl gas in die hyle he ollowing he li e a u e p ocedu e desc ibed o iphenyl- phosphine hyd ochlo ide[13] (99). N-Benzylpy olidine hyd ochlo ide (62) and N-benzylpipe idine hyd ochlo ide (58) we e syn hesized di ec ly om benzyl chlo ide and py olidine o pipe idine ollowing he li e a u e p ocedu e o 1-benzyl-3-me hylimidazolium chlo ide[3] (8). Phosphonium Sal s T ihexyl e adecylphosphonium chlo ide (93), bu yl iphenylphosphonium chlo ide (95), e abu ylphosphonium chlo ide (97), e aphenylphosphonium chlo ide (98), and iphenylphosphine dichlo ide (100) we e pu chased om ABCR. Benzyl ibu ylphoshonium chlo ide (94) and benzyl iphenylphosphonium chlo ide (96) we e syn hesized om he co esponding e ia y phosphine and benzyl chlo ide ollowing he li e a u e p ocedu e o 1-benzyl-3-me hylimidazolium chlo ide[3] (8). T iphenylphosphine hyd ochlo ide was syn hesized acco ding o he li e a u e[13] (99). 6 Nickel Ca alyzed P opene Dime iza ion Reac ions in BiPh3 Bu e ed Chlo oalumina e Ionic Liquids: High Pe o mance wi h Uncon en ional Ca ions 93 6.4.3 Ca ion Sc eening Qua e na y Ammonium Sal s Table 1: Ca ion sc eening o nickel ca alyzed p opene dime iza ion eac ions in BiPh3 bu e ed chlo oalumina e mel s (so ed in descending o de o selec i i ies in un 1).[1] No. Ca ion Run 1 C6 [%] P od.[2] Run 2 Run 3 Run 4 Run 5 Run 6 Run 7 Run 8 Run 9 Run 10 Run 11 1 95.1 6.0 93.5 7.3 87.6 > 10.1 70.2 9.5 69.3 8.9 62.5 7.5 2 92.3 8.9 91.9 9.7 91.9 > 10.5 89.9 > 11.1 76.9 > 12.0 61.3 7.8 Oil 7.0 3 92.0 7.8 92.1 9.0 90.2 9.2 88.0 > 11.7 80.5 > 10.5 65.4 7.9 61.9 7.1 4 91.6 > 13.1 89.6 > 12.3 87.2 > 14.0 71.8 > 11.4 61.9 9.0 56.2 7.3 5 91.5 > 12.4 89.7 > 12.1 86.2 > 14.1 76.4 > 11.4 74.5 > 11.5 74.0 11.2 77.6 9.0 77.7 8.7 77.2 6.4 68.3 5.9 6 91.4 9.0 80.3 > 15.2 69.5 > 11.2 67.2 9.1 67.2 7.5 63.8 6.8 7 91.2 > 10.8 89.7 > 11.4 86.5 > 10.9 83.7 > 10.6 75.3 > 10.6 70.8 8.9 69.6 6.9 8 90.9 > 9.4 89.5 > 10.7 88.0 > 12.2 75.9 > 11.2 65.6 9.7 59.5 7.4 Oil 6.8 9 90.9 > 11.7 91.4 > 10.8 91.7 > 11.2 91.6 9.9 91.1 > 10.9 90.3 > 11.3 89.0 > 10.2 86.0 > 11.4 78.5 > 10.7 70.9 8.8 71.1 8.4 10 90.9 > 8.7 92.3 > 10.4 91.9 > 9.3 92.0 > 9.2 91.8 > 9.8 89.4 > 9.4 89.1 > 11.7 80.0 > 11.0 73.5 7.7 11 90.7 > 11.9 87.9 > 10.5 86.7 > 11.9 76.6 > 11.5 60.0 9.3 12 90.7 > 13.4 88.9 > 14.1 82.5 > 14.2 67.4 > 14.0 65.3 10.9 62.8 9.7 6 Nickel Ca alyzed P opene Dime iza ion Reac ions in BiPh3 Bu e ed Chlo oalumina e Ionic Liquids: High Pe o mance wi h Uncon en ional Ca ions 94 No. Ca ion Run 1 C6 [%] P od.[2] Run 2 Run 3 Run 4 Run 5 Run 6 Run 7 Run 8 Run 9 Run 10 Run 11 13 90.5 8.9 89.9 8.3 90.1 10.4 89.1 9.4 86.7 12.7 77.4 > 14.5 72.3 9.1 62.6 6.1 14 90.3 > 9.5 90.0 > 11.3 86.0 > 13.6 73.6 > 13.1 72.3 8.8 69.3 6.4 65.2 5.4 15 90.3 7.0 91.9 7.6 91.9 7.1 91.8 9.1 89.9 > 10.1 74.9 > 10.4 71.2 8.8 66.7 5.4 16 90.1 10.3 89.8 10.4 89.1 > 11.5 89.0 > 11.6 71.7 > 11.6 63.2 9.2 17 90.0 > 9.9 89.4 > 9.1 90.9 > 10.8 89.3 > 8.7 89.5 > 9.9 88.8 > 9.6 86.5 > 9.6 84.0 > 9.4 67.8 7.7 64.6 8.8 18 89.9 > 11.6 89.2 > 13.3 83.0 > 14.2 63.0 10.8 60.2 9.9 19 89.7 > 13.0 89.9 > 14.3 88.8 > 14.4 85.9 > 12.7 77.8 > 14.5 75.4 > 14.0 74.0 7.6 66.9 4.6 20 89.6 > 7.8 90.1 > 8.9 86.0 > 10.1 79.7 > 9.2 65.1 > 7.6 72.8 > 7.7 55.5 5.1 21 89.6 8.1 91.5 8.4 92.0 9.4 92.2 8.9 92.4 9.2 91.7 9.6 90.8 9.6 90.2 > 10.7 86.8 > 11.1 78.4 > 10.2 77.9 5.5 22 89.3 > 11.5 86.4 > 11.9 85.1 > 12.6 81.8 > 13.4 58.0 8.5 55.9 8.0 23 89.3 > 9.0 91.3 > 9.5 92.2 > 10.5 91.5 > 10.7 91.0 > 10.1 90.9 > 10.9 89.3 > 10.0 84.3 > 12.9 77.2 > 11.0 74.2 8.9 Oil 7.7 24 89.2 > 11.5 86.6 > 12.6 84.9 > 12.8 75.4 > 12.9 64.5 8.8 25 89.0 8.3 84.1 > 10.6 77.3 8.1 59.1 8.8 6 Nickel Ca alyzed P opene Dime iza ion Reac ions in BiPh3 Bu e ed Chlo oalumina e Ionic Liquids: High Pe o mance wi h Uncon en ional Ca ions 95 No. Ca ion Run 1 C6 [%] P od.[2] Run 2 Run 3 Run 4 Run 5 Run 6 Run 7 Run 8 Run 9 Run 10 Run 11 26 88.9 > 10.6 89.1 > 10.9 78.2 > 11.9 63.5 > 10.1 27 88.6 > 9.3 84.3 > 9.0 81.0 > 11.2 64.0 > 9.0 28 88.0 > 9.6 87.9 > 9.5 87.2 > 10.1 85.9 > 10.7 83.5 > 10.8 80.4 > 11.7 74.1 > 10.4 71.4 > 10.6 70.1 > 9.72 69.0 > 8.7 64.2 7.4 29 87.3 8.0 69.3 7.5 73.8 7.2 66.5 9.7 30 86.7 > 10.8 87.6 > 10.4 86.1 > 10.7 86.3 > 10.0 85.3 > 10.7 85.3 > 11.7 82.3 > 11.6 70.2 > 9.3 69.3 8.3 31 86.2 > 10.2 85.8 > 11.2 81.4 > 12.2 68.7 > 12.6 63.5 9.0 32 85.1 6.8 82.6 7.8 73.7 > 10.3 70.2 > 9.5 67.1 8.1 65.7 5.3 33 84.9 > 7.8 87.2 > 9.1 87.2 > 9.4 88.1 > 10.3 88.0 > 9.7 87.2 > 9.2 86.6 > 10.4 83.6 > 10.1 79.7 > 10.4 76.5 > 8.3 75.4 7.1 34 80.3 > 10.0 55.9 4.7 35 75.9 > 9.0 70.1 > 11.9 70.9 > 9.8 71.3 > 8.7 70.6 > 7.9 70.8 8.8 64.4 6.1 36 50.5 9.5 Oil 8.6 37 Oil (decomp.) 7.3 [1] Reac ion condi ions: 2.5 – 4.0 g bu e ed ionic liquid; composi ion [BiPh3] / [ca ion]+[Al2Cl6X]− = 0.30 (X = Cl, B ); chlo ide sal s i no o he wise men ioned; ca alys p ecu so A; [ca ] = 10–5 mol / gionic liquid; T = 25°C; s i ing a e = 1200 min–1; = 60 min; 300 ml glass au ocla e; 40 – 60 ml liquid p opene; p oduc s decan ed a e each un; > = comple e con e sion; Oil = only highe oligome s. [2] P oduc i i y gi en in gp oduc / gionic liquid x h. 6 Nickel Ca alyzed P opene Dime iza ion Reac ions in BiPh3 Bu e ed Chlo oalumina e Ionic Liquids: High Pe o mance wi h Uncon en ional Ca ions 96 Hyd ochlo ides o P ima y and Seconda y Amines Table 2: Ca ion sc eening o nickel ca alyzed p opene dime iza ion eac ions in BiPh3 bu e ed chlo oalumina e mel s (so ed in descending o de o selec i i ies in un 1).[1] No. Ca ion Run 1 C6 [%] P od.[2] Run 2 Run 3 Run 4 Run 5 Run 6 Run 7 Run 8 Run 9 38 90.4 > 9.1 88.5 > 8.2 88.5 9.9 70.4 > 11.5 66.5 > 9.9 63.4 6.7 39 83.0 3.1 84.1 4.1 78.5 5.2 70.0 8.5 69.9 6.5 65.0 5.0 40 79.0 6.0 79.3 5.9 74.1 > 9.5 65.2 > 9.7 67.4 6.8 71.5 6.5 67.5 5.4 67.3 3.3 41 76.1 > 8.8 72.6 > 10.8 70.2 > 10.0 70.1 > 9.3 62.0 8.6 42 73.3 > 7.9 71.5 > 7.8 76.6 > 7.9 69.5 > 7.7 68.1 > 8.1 60.7 > 8.4 65.6 > 8.1 66.5 > 7.1 69.2 5.8 43 73.0 > 9.6 65.0 > 10.6 61.3 > 9.2 44 67.7 > 10.1 62.3 > 8.4 60.4 8.3 57.0 5.9 Oil 5.4 45 66.1 > 9.8 68.1 > 9.9 72.1 7.6 69.5 6.3 69.3 4.6 49.7 4.5 Oil 3.9 46 64.3 > 13.8 63.6 > 12.1 Oil > 9.9 47 60.9 > 9.8 48 59.7 > 12.8 68.0 > 13.1 67.2 > 12.1 72.6 > 13.5 73.5 11.1 73.4 5.9 62.1 4.7 49 Oil 6.8 6 Nickel Ca alyzed P opene Dime iza ion Reac ions in BiPh3 Bu e ed Chlo oalumina e Ionic Liquids: High Pe o mance wi h Uncon en ional Ca ions 97 No. Ca ion Run 1 C6 [%] P od.[2] Run 2 Run 3 Run 4 Run 5 Run 6 Run 7 Run 8 Run 9 50 Oil 6.5 51 Bu e ed IL solid [1] Reac ion condi ions: 2.5 – 4.0 g bu e ed ionic liquid; composi ion [BiPh3] / [ca ion]+[Al2Cl7]− = 0.30; ca alys p ecu so A; [ca ] = 10–5 mol / gionic liquid; T = 25°C; s i ing a e = 1200 min–1; = 60 min; 300 ml glass au ocla e; 40 – 60 ml liquid p opene; p oduc s decan ed a e each un; > = comple e con e sion; Oil = only highe oligome s. [2] P oduc i i y gi en in gp oduc / gionic liquid x h. Hyd ochlo ides o Te ia y Amines Table 3: Ca ion sc eening o nickel ca alyzed p opene dime iza ion eac ions in BiPh3 bu e ed chlo oalumina e mel s (so ed in descending o de o selec i i ies in un 1).[1] No. Ca ion Run 1 C6 [%] P od.[2] Run 2 Run 3 Run 4 Run 5 Run 6 Run 7 Run 8 Run 9 Run 10 Run 11 52 93.1 7.4 93.6 8.3 94.1 7.5 92.0 8.1 78.0 > 10.5 69.6 8.8 56.7 7.4 53 93.1 7.8 93.3 8.2 92.9 9.5 91.5 8.8 87.4 11.0 73.4 8.6 67.4 6.5 54 93.1 8.7 91.1 7.3 91.1 8.3 80.4 > 10.5 57.8 9.8 Oil 7.3 55 92.8 9.3 93.2 8.2 93.0 7.6 93.1 7.5 90.6 8.5 71.6 10.0 63.6 7.0 Oil 6.7 56 92.7 10.1 92.4 9.4 90.0 9.2 87.6 > 10.6 65.9 10.6 61.9 8.7 Oil 8.0 57 92.5 10.1 92.8 9.6 91.8 8.5 91.5 9.6 89.0 > 9.2 83.0 > 12.2 73.1 10.8 69.2 8.1 67.4 6.6 58 92.4 9.1 91.2 9.0 89.0 9.1 84.0 > 12.8 71.4 10.5 62.6 7.4 6 Nickel Ca alyzed P opene Dime iza ion Reac ions in BiPh3 Bu e ed Chlo oalumina e Ionic Liquids: High Pe o mance wi h Uncon en ional Ca ions 98 No. Ca ion Run 1 C6 [%] P od.[2] Run 2 Run 3 Run 4 Run 5 Run 6 Run 7 Run 8 Run 9 Run 10 Run 11 59 92.0 7.9 91.3 7.7 89.5 8.6 86.1 > 9.1 75.2 7.1 66.2 4.5 60 91.7 9.0 90.3 8.6 90.0 9.0 86.0 9.1 74.0 9.2 66.7 10.0 65.7 6.3 Oil 6.1 61 91.6 7.6 93.5 8.2 93.3 7.5 93.1 7.6 93.1 8.1 91.8 8.9 91.1 > 11.2 81.8 > 10.5 70.2 8.8 Oil 6.7 62 91.0 > 11.8 91.7 > 11.4 90.4 > 10.5 89.8 > 12.0 88.0 > 14.0 77.8 > 13.0 74.6 > 12.3 72.0 > 11.3 70.9 > 10.8 66.6 6.8 63 90.8 > 9.8 91.5 > 10.8 90.3 > 10.0 89.8 > 11.4 88.0 > 11.1 79.8 > 13.7 74.0 9.3 68.3 5.2 64 90.7 > 10.1 90.0 > 10.0 90.4 > 10.2 90.0 > 10.1 87.7 > 10.5 85.7 > 11.8 72.2 > 10.3 64.4 > 7.4 65 90.0 > 10.6 89.7 > 9.4 90.0 > 11.5 89.2 > 10.9 89.2 > 12.5 86.2 > 11.6 73.9 > 11.0 68.3 > 9.6 67.5 8.0 64.3 7.0 66 90.0 > 8.2 90.0 > 9.5 87.5 > 8.7 81.3 > 9.6 71.6 > 9.3 65.3 8.1 65.2 5.8 58.4 4.6 67 90.0 > 10.9 90.2 > 10.3 89.6 > 10.2 88.1 > 11.2 85.6 > 12.4 76.8 > 10.6 73.7 > 10.6 71.3 8.0 66.5 6.3 68 90.0 > 8.8 90.6 > 8.6 77.5 > 11.3 60.4 > 8.3 69 89.9 > 8.4 89.6 > 9.3 90.2 > 9.0 88.8 > 8.2 88.8 > 8.3 88.3 > 10.1 85.1 > 9.1 79.7 > 9.2 67.0 7.3 70 89.6 > 10.8 90.0 > 10.6 89.7 > 9.4 89.2 > 10.2 88.5 > 11.5 86.0 > 9.2 76.1 > 9.5 70.8 8.0 68.3 5.8 71 89.6 7.6 86.3 > 8.7 82.6 > 9.7 69.4 > 9.4 Oil > 8.0 6 Nickel Ca alyzed P opene Dime iza ion Reac ions in BiPh3 Bu e ed Chlo oalumina e Ionic Liquids: High Pe o mance wi h Uncon en ional Ca ions 99 No. Ca ion Run 1 C6 [%] P od.[2] Run 2 Run 3 Run 4 Run 5 Run 6 Run 7 Run 8 Run 9 Run 10 Run 11 72 89.6 > 13.2 73.1 > 13.4 68.2 11.8 66.3 9.2 73 89.5 > 10.7 89.9 > 12.7 89.0 > 11.6 84.1 > 10.6 75.8 > 11.6 72.7 8.9 67.4 4.5 74 89.5 > 10.3 89.0 > 11.3 90.0 > 10.6 88.3 > 10.9 80.9 > 12.3 72.0 > 9.3 70.4 8.6 65.6 7.8 60.8 5.8 75 89.4 > 8.0 89.7 > 8.8 87.3 > 7.9 86.8 > 11.2 84.7 > 9.6 78.8 > 8.9 70.4 > 8.1 68.3 8.6 67.4 8.3 67.5 6.9 76 89.4 > 10.6 90.0 > 11.1 89.8 > 10.9 88.3 > 10.6 86.3 > 12.7 77.1 > 11.5 70.7 8.6 64.3 4.1 77 89.1 > 8.7 91.7 > 8.6 91.9 > 8.6 92.5 > 8.6 92.0 > 8.5 90.2 > 8.5 91.6 > 8.3 91.1 > 10.0 89.2 > 10.2 77.4 8.6 73.3 6.1 78 89.0 > 9.4 89.9 > 9.6 88.9 > 11.2 84.8 > 12.1 76.4 > 11.7 74.7 > 11.7 71.7 10.1 66.6 7.3 79 88.7 > 9.9 88.2 > 9.7 86.7 > 10.9 86.1 > 12.2 80.9 > 12.0 74.6 > 10.5 69.1 7.4 Oil 2.5 80 88.3 > 8.1 87.0 > 10.1 85.5 > 10.5 81.5 > 10.5 71.1 > 9.7 67.8 7.1 67.2 6.0 81 88.2 > 10.7 88.6 > 10.6 88.5 > 11.2 87.5 > 11.0 86.5 > 11.9 84.0 > 11.9 79.2 > 13.1 73.4 > 10.2 73.0 > 10.0 73.0 8.8 70.9 7.3 82 88.0 > 8.6 89.7 > 9.5 89.4 > 9.7 88.5 > 10.2 87.8 > 11.5 83.6 > 10.3 76.6 > 10.8 70.5 > 9.2 83 87.9 > 12.5 88.3 > 12.2 87.5 > 12.3 87.4 > 12.3 83.8 > 12.8 76.0 > 12.9 66.8 8.3 7 Bu e ed Aluminum Chlo ide as Highly E icien Coca alys o Ole in Dime iza ion and Polyme iza ion Reac ions 106 Nickel complexes a e no only used o ole in oligome iza ion and dime iza ion eac ions, hey we e also ound o be e icien o ole in polyme iza ion eac ions. In 1995, B ookha e al. i s desc ibed e hene polyme iza ion eac ions wi h highly ac i e nickel complexes based on no el bulky diimine ligands ac i a ed wi h me hylalumino- xane (MAO).[12] Be o e, polyme iza ion only occu ed occasionally wi h such Ziegle ype nickel oligome iza ion sys ems. Howe e , p edic ions how ca alys s and ligands ha e o be designed o p oduce polyme s selec i ely we e di icul .[3b] In he las en yea s, SHOP ype ca alys s we e op imized o polyme ize e hene, oo.[7, 13] Howe e , hei ac i i y canno compe e wi h MAO ac i a ed nickel diimine sys ems. Due o he in ensi e esea ch launched by a B ookha epo , many nickel diimine based ole in polyme i- za ion ca alys s a e known oday.[14] While he SHOP ca alys consis s o a single componen , which usually displays low ac i i y, mos o he nickel based dime iza ion o polyme iza ion sys ems ely on aluminum based ac i a o s. Common coca alys s a e MAO and i s de i a i es, e hyl- aluminum dichlo ide, die hylaluminum chlo ide, ie hylaluminum, ime hylaluminum, o mix u es he eo .[1a, 12, 14-15] Un o una ely, all aluminum coca alys s used so a bea an alkyl g oup in o de o gua an ee hei solubili y in nonpola o ganic sol en s as well as o educe hei Lewis acidi y compa ed o aluminum ichlo ide.[16] The la e ca alyzes side eac ions like isome iza ion, c acking, disp opo iona ion o alkanes as well as alkyla ion o a oma ics wi h alkenes and ca ionic oligome iza ion o ole ins.[17] Fu he mo e, he p oposed mechanism based on he inse ion o monome s in o Ni–H o Ni–C bonds o nickel(II) complexes equi es an alkyla ing agen . Alkylaluminum compounds a e py opho ic and highly sensi i e o wa e , oxygen, o pola impu i ies. Thus, hey a e mos ly he cos de e mining ac o o comme cial applica ions. Feed s eams ha e o be pu i ied ho oughly p io o he eac ions, and he high eac i i y equi es a cau ious handling. Finally, he coca alys s a e des oyed upon p oduc sepa a ion o he homogeneous eac ions.[8c] Also, alkylaluminum coca alys s con ibu e o he deac i a ion o ac i e Ni(II) ca alys s by educing Ni(II) o i s ze o oxida ion s a e.[18] The e o e, he de elopmen o insensi i e AlCl3 based coca alys sys ems would be highly desi able in e ms o p ocess economics. 7 Bu e ed Aluminum Chlo ide as Highly E icien Coca alys o Ole in Dime iza ion and Polyme iza ion Reac ions 107 Figu e 3: B ookha ype nickel diimine complex used o e hene polyme iza ion eac ions wi h bu e ed AlCl3 ac i a o s. Ionic liquids syn hesized om AlCl3 a e an elegan a emp o o e come he ecycling and solubili y es ic ions o sys ems based solely on AlCl3.[19] In combina ion wi h ce ain o ganic ca ions, AlCl3 o ms liquids a ambien empe a u e o e a wide ange o composi ions, which a e immiscible wi h hyd oca bon phases. The Lewis acidi ies o such chlo oalumina e ionic liquids can be adjus ed om basic o e neu al o acidic simply by a ying he AlCl3 / halide sal a io.[20] Howe e , basic o neu al liquids do no ac i a e nickel ca alys s, while acidic composi ions p edominan ly ca alyze side eac ions like uncon olled ca ionic oligome iza ion o ole ins[17b, 21] as well as isome iza ion[22] and c acking[23] eac ions o sa u a ed alkanes. Chau in e al. supp essed such ca ionic ole in oligome iza ion eac ions by he addi ion o E AlCl2 o sligh ly acidic chlo oalumina e mel s. These mel s we e able o ac i a e nickel complexes o selec i e dime iza ion eac ions o α-ole ins.[24] The IFP b ough his so called DIFASOL® p ocess o indus ial applica ion by e o i ing i o hei exis ing homogeneous DIMERSOL® uni s.[9c, 10-11] Howe e , he use o e hylaluminum dichlo ide es ic s he use o DIFASOL® sys ems. They can only be ope a ed in combina ion wi h DIMERSOL® uni s, which p e iously emo e all impu i ies om he eed s eam. O he wise, impu i ies would accumula e in he ionic liquid, and ecycling o he mel a e i s deple ion is no in ended.[9a, 9c] In 1998, Wasse scheid epo ed he i s biphasic sys em o nickel ca alyzed ole in dime iza ion eac ions exclusi ely based on AlCl3.[25] He used weak o ganic bases like py idine, quinoline, o py ole de i a i es o educe he “la en acidi y”[26] o chlo oalumina e ionic liquids. The in e ac ion o he ni ogen bases wi h AlCl3 o he [Al2Cl7]− species p esen in such liquids[19a, 27] supp essed uncon olled ca ionic ole in 7 Bu e ed Aluminum Chlo ide as Highly E icien Coca alys o Ole in Dime iza ion and Polyme iza ion Reac ions 108 oligome iza ion eac ions. The bu e ed chlo oalumina e mel s we e used o ac i a e nickel complexes o selec i e dime iza ion eac ions o a ious α-ole ins.[28] Single componen equi alen s o he Lewis base in e ac ion wi h aluminum in ionic liquids a e in amolecula dono -s abilized aluminum coca alys s. Se e al o such aluminum compounds s abilized by pending in amolecula ni ogen,[29] phospho us,[30] oxygen,[31] o sul u [32] g oups ha e been desc ibed and used as coca alys s. Howe e , hese in amolecula s abilized aluminum compounds o en equi e la ge syn he ic e o s and s ill con ain eac i e Al–C bonds. The e o e, hey a e no cheap al e na i e o common alkylaluminum coca alys s o la ge comme cial applica ions. Recen ly, we desc ibed he use o iphenylphosphine and iphenylbismu h as highly e icien bu e s o Lewis acidic chlo oalumina e ionic liquids[33] and in es iga ed he in e ac ion o he basic phosphine cen e wi h he Lewis acidic aluminum species by 27Al NMR and 31P NMR spec oscopy.[34] In he cou se o ou sea ch o cheap and insensi i e coca alys s o nickel ca alyzed ole in dime iza ion and polyme iza ion eac ions, we ex ended he concep o bu e ing highly Lewis acidic aluminum chlo ide cen e s o wo componen homogeneous sys ems. 7.2 Resul s and Discussion NMR In es iga ions o Dono -Accep o In e ac ions o Aluminum Chlo ide wi h N- Me hylpy ole and T iphenylbismu h The mos e icien bu e s o Lewis acidic chlo oalumina e mel s we e ound o be N- me hylpy ole[28a] (N-MP) and iphenylbismu h.[33] The e o e, we i s in es iga ed wha happened o AlCl3 in oluene i equimola amoun s o hese wo bu e s we e added. Su p isingly, he ini ially insoluble anhyd ous AlCl3 comple ely dissol ed upon bu e addi ion. Ob iously, he dono -accep o in e ac ion be ween he bu e and he Al cen e was su icien o b eak up he dime ic Al2Cl6 s uc u e o aluminum chlo ide. The o ganic bu e s ongly inc eased he solubili y o AlCl3 by o ming a weak adduc . I was also possible o dissol e bu e adduc s o aluminum chlo ide in CH2Cl2. Howe e , in he case o N-MP, he sys em s a ed o loccula e slowly. We assume ha he s ong Lewis acid AlCl3 ca alyzed a ing opening eac ion o he ni ogen he e ocycle. No p ecipi a ion 7 Bu e ed Aluminum Chlo ide as Highly E icien Coca alys o Ole in Dime iza ion and Polyme iza ion Reac ions 109 occu ed wi h he iphenylbismu h adduc o e se e al hou s. We examined hese in e ac ions by 27Al NMR spec oscopy (Scheme 1). Scheme 1: 27Al NMR spec a o he dono -accep o in e ac ion o AlCl3 wi h di e en dono s a 25°C (A: 1 equi alen BiPh3, 0.05 N AlCl3 in oluene, ace C6D6; B: 10 equi alen s N-MP, 0.1 N AlCl3 in oluene, ace C6D6; C: 1 equi alen N-MP, 0.1 N AlCl3 in oluene, ace C6D6; D: 1 equi alen N-MP, 0.1 N AlCl3 in CH2Cl2, ace CDCl3;). The measu emen s we e pe o med in oluene wi h a ew d ops o C6D6 and in CH2Cl2 wi h addi ional CDCl3. The aluminum con aining p obehead o he NMR spec ome e appea ed a ound δ = 80 ppm as b oad signal. Fo BiPh3 adduc s, an AlCl3 concen a ion o 0.05 N was chosen. The solubili ies o N-MP adduc s we e highe , and hus, a 0.1 N sys em was measu ed. The compounds we e mixed and he spec a eco ded wi hin a ew minu es due o he decomposi ion o AlCl3 / N-MP adduc s. All 27Al NMR signals appea ed a ound δ = 128 ppm. Howe e , he b oadness o he signals di e ed s ongly. The b oades peak was obse ed o he BiPh3 / AlCl3 in e ac ion in oluene wi h a line wid h a hal maximum o 1200 Hz (A). Wi h a en old excess o N- MP in oluene, he line wid h was 480 Hz (B) while i dec eased o 330 Hz wi h only one equi alen o N-MP (C). The sha pes signal wi h a line wid h a hal maximum o 190 Hz 7 Bu e ed Aluminum Chlo ide as Highly E icien Coca alys o Ole in Dime iza ion and Polyme iza ion Reac ions 110 was ob ained om an equimola composi ion o AlCl3 and N-MP in me hylene chlo ide (D). The shoulde s in spec a A and B p obably belong o decomposi ion p oduc s, which we e no iden i ied. The shoulde inc eased o sys em B o e ime. The b oadness o he 27Al NMR signal allowed conclusions abou he ex en o he dono -accep o in e ac ion. Fo example, he 27Al NMR signal was b oadened i en equi alen s ins ead o one equi alen o N-MP we e added. In con as , he in e ac ion be ween N-MP and AlCl3 in me hylene chlo ide was less in ensi e indica ed by a ela i ely sha p signal. The mo e pola sol en me hylene chlo ide in e ac ed mo e s ongly wi h he adduc inc easing he a e age dis ance be ween he dono and he accep o . Homogeneous P opene Dime iza ion Reac ions Fu he , we we e in e es ed i such adduc s s ill displayed su icien ly high Lewis acidi ies o ac i a e nickel complexes. In bu e ed ionic liquids, only small amoun s o bu e compa ed o he AlCl3 con en we e employed. Fo AlCl3 / bu e adduc s in homogeneous solu ion a leas equimola amoun s o bu e we e necessa y o dissol e aluminum chlo ide. In a i s se ies o expe imen s we ied o ac i a e (PCy3)2NiCl2 wi h 850 equi alen s o he homogeneous AlCl3 adduc s in o de o selec i ely dime ize p opene. S e ically demanding phosphine ligands like icyclohexylphosphine we e known o a ou he o ma ion o aluable highly b anched dime s in nickel ca alyzed dime iza ion eac ions.[2a, 15e, 16] The o ma ion o 2,3-dime hylbu enes is highly desi able due o hei high esea ch oc ane numbe (RON). They can be sold as high oc ane mo o uels o used o inc ease he RON o low oc ane ac ions.[35] All expe imen s success ully p oduced dime s (Table 1). The iphenylbismu h adduc yielded 72% dime s in oluene (1) and 59% dime s in CH2Cl2 (2). E en when he CH2Cl2 sol en was emo ed a e adduc o ma ion, he sol en ee sys em yielded 73% dime s (3). Thus, he adduc was soluble in ole ins like p opene, oo. The bes esul was ob ained wi h N-MP in oluene wi h 95% C6 p oduc s (4). All AlCl3 composi ions displayed eno mous ac i i ies up o almos 32 on pe mol nickel and hou (2). Fo sys ems wi h highe selec i i ies o C6, he ac i i ies dec eased while highe ac i i ies we e ob ained wi h less selec i e sys ems. The highes con en o 2,3-dime hylbu enes 7 Bu e ed Aluminum Chlo ide as Highly E icien Coca alys o Ole in Dime iza ion and Polyme iza ion Reac ions 111 was p oduced wi h BiPh3 in oluene (53%). Gene ally, eac ions in oluene we e mo e selec i e han eac ions in CH2Cl2. This was in acco dance wi h ou 27Al NMR in es i- ga ions. A sha pe 27Al NMR signal indica ed a weake dono -accep o in e ac ion, and hus, a highe Lewis acidi y compa ed o oluene based sys ems. The esul s indica ed ha he N-MP bu e was supe io o iphenylbismu h in e ms o dime selec i i y. In con as , BiPh3 educed he a es o ligand abs ac ion mo e e icien ly. T iphenyl- bismu h bu e ed sys ems always yielded highe 2,3-dime hylbu ene con en s han simila N-MP bu e ed composi ions. This migh also be a ibu ed o addi ional π-in e - ac ions o he h ee a oma ic ings in BiPh3. The addi ion o a oma ic addi i es was ound o main ain he phosphine e ec o e ex ended pe iods o ime.[24b] Ce ainly, sys ems bu e ed by a combina ion o N-MP and BiPh3 should esul in high selec i i ies o bo h dime s and 2,3-dime hylbu enes. Fo compa ison, h ee expe imen s using an e hylaluminum dichlo ide coca alys in oluene we e also pe o med. Wi hou bu e , only 36% dime s we e o med unde he applied eac ion condi ions (5). I equimola amoun s o BiPh3 o N-MP we e added o he e hylaluminum dichlo ide solu ion, he dime selec i i ies d as ically inc eased o 75% (6) and 95% (7), espec i ely. As can be seen om bo h AlCl3 and E AlCl2 based sys ems, highe dime selec i i ies came along wi h highe deg ees o b anching and educed ac i i ies. Thus, such sys ems p o ide a lo o possibili ies o op imize he esul s simply by a ying pa ame e s like sol en s, bu e excess o ype and amoun o ligand. De ini ely, bu e ed aluminum based coca alys s a e a p omising al e na i e o alkylaluminum sys ems used in DIMERSOL® plan s. Especially he insensi i e N-MP / AlCl3 adduc s can easily eplace E AlCl2 o E 2AlCl coca alys s. Upon hyd olysis, esidual N-MP can emain in he p oduc phase i i is used o blend gasoline, while only e y cheap aluminum chlo ide is consumed. Aluminum chlo ide as well as iphenyl- bismu h and N-MP can be s o ed in ai and unlike aluminum alkyls, hey do no equi e an ex emely cau ious handling. The componen s can be mixed quickly p io o use. Thus, he e y slow decomposi ion o N-MP is negligible unde he applied condi ions. 7 Bu e ed Aluminum Chlo ide as Highly E icien Coca alys o Ole in Dime iza ion and Polyme iza ion Reac ions 112 Table 1: Homogeneous nickel ca alyzed p opene dime iza ion eac ions wi h bu e ed AlCl3 coca alys s.[1] No. Lewis Acid Bu e Sol en C6 [%] HEX [%] MP [%] DMB [%] Ac i i y[2] 1 AlCl3 BiPh3 Toluene 71.6 7 40 53 10.24 2 AlCl3 BiPh3 CH2Cl2 59.1 22 73 5 31.72[3] 3 AlCl3 BiPh3 – 73.0 19 57 24 2.67 4 AlCl3 N-MP Toluene 95.3 17 59 24 5.55 5 E AlCl2 – Toluene 36.1 22 72 6 8.76 6 E AlCl2 BiPh3 Toluene 75.2 4 41 55 7.62 7 E AlCl2 N-MP Toluene 95.3 11 53 36 1.13 [1] Reac ion condi ions: 3 – 6 mg (PCy3)2NiCl2; [Al] / [Ni] = 850; [Al] / [bu e ] = 1; 50 ml sol en ; T = 40°C; s i ing a e = 600 min–1; = 60 min; s i ed 300 ml Pa s ainless s eel au ocla e; 200 ml liquid p opene; HEX = n-hexenes; MP = 2-me hylpen enes; DMB = 2,3-dime hylbu enes; N-MP = N-me hylpy ole. [2] p oduc / molNi x h. [3] Ex apola ed; eac ion was s opped a e 30 min due o an ex emely high ac i i y. Homogeneous E hene Polyme iza ion Reac ions Since nickel complexes we e success ully ac i a ed o dime ize p opene wi h ou sys em, we ex ended he s udy o e hene polyme iza ion eac ions. The e o e, a ypical B ookha ype nickel diimine complex was employed as ca alys p ecu so (Scheme 2). The complex is known o polyme ize e hene upon ac i a ion wi h me hylaluminoxane o E 2AlCl.[12, 14b, 14c] Table 2 summa izes he esul s o he e hene polyme iza ion eac ions wi h complex 1. In all expe imen s employing iphenylbismu h o N-me hylpy ole as bu e , polyme s we e p oduced (Table 3). While he oluene based ca alys s 8 – 10 yielded polye hylenes wi h simila molecula weigh s a ound 140 kg/mol, he sys em dissol ed in me hylene chlo ide yielded polye hylene wi h a molecula weigh o only 75 kg/mol (11). Ce ainly, his e ec was a ibu ed o he inc eased Lewis acidi y in me hylene chlo ide. Among all oluene based sys ems, he iphenylbismu h bu e ed sys em (8) 7 Bu e ed Aluminum Chlo ide as Highly E icien Coca alys o Ole in Dime iza ion and Polyme iza ion Reac ions 113 led o he polye hylene wi h he highes PDI in combina ion wi h he lowes deg ee o c ys allini y and he lowes mel ing poin . Rema kably, he PDI o he polye hylene ob ained wi h he N-me hylpy ole bu e ed sys em was educed om 2.55 (9) o 2.25 (10) by he addi ion o an excess o i e equi alen s o bu e while molecula weigh s, mel ing poin s, and deg ees o c ys allini y emained unchanged. Table 2: Homogeneous nickel ca alyzed e hene polyme iza ion eac ions wi h bu e ed AlCl3 coca alys s.[1] No. Sol en Reac ion Time [min] Bu e [Al] / [Ni] PE [w %] Oligome s [w %] C4 [%][2] 1-C4 [%][3] Ac i i y[4] 8 Toluene 30 BiPh3 500 38 62 83.3 67.6 1.48 9 Toluene 30 N-MP 500 7 93 87.0 53.7 2.77 10 Toluene 30 N-MP 500[5] 19 81 91.5 79.4 0.69 11 CH2Cl2 10 BiPh3 200 12 88 71.9 20.2 16.54 12 CH2Cl2 60 PPh3 500 0 100 no de . no de . 0.04 [1] Reac ion condi ions: 8 – 15 mg ca alys p ecu so 1; AlCl3 ac i a o ; [bu e ] / [Al] = 1; 50 ml sol en ; T = 40°C; s i ing a e = 600 min–1; s i ed 300 ml Pa s ainless s eel au ocla e; 10 ba e hene; PE = polye hylene; N-MP = N-me hylpy ole. [2] Mola amoun o bu enes wi hin oligome ac ion. [3] Mola amoun o 1-bu ene wi hin bu enes. [4] p oduc / molNi x h. [5] [bu e ] / [Al] = 5. Howe e , la ge amoun s o oligome s we e o med besides he polye hylenes. The highes polyme con en o 38 w % was ob ained wi h BiPh3 in oluene a an Al o Ni a io o 500 (8). A e he bu e was used in excess o aluminum chlo ide, he polyme con en could be inc eased om 7 w % o he equimola composi ion (9) o 19 w % wi h a i e old excess o N-MP in oluene (10). 7 Bu e ed Aluminum Chlo ide as Highly E icien Coca alys o Ole in Dime iza ion and Polyme iza ion Reac ions 114 Table 3: Polye hylene p ope ies. No. Mn [kg/mol] Mw [kg/mol] PDI Tm [°C] Xc [%][1] 8 49 141 2.87 114.6 4 9 55 141 2.55 121.1 32 10 60 134 2.25 121.8 30 11 26 75 2.88 105.4 2 [1] C ys allini y calcula ed wi h ∆Hm = 293 J/g o 100% c ys alline PE. To summa ize, he iphenylbismu h bu e led o he o ma ion o highe amoun s o polyme s compa ed o N-me hylpy ole. In con as , N-me hylpy ole bu e ed sys ems yielded polye hylenes wi h highe deg ees o c ys allini y and smalle PDIs. Thus, hese bu e ed aluminum chlo ide based coca alys sys ems p o ide a lo o possibili ies o maximize he yield o polyme s and o in luence hei p ope ies. Su p isingly, he oligome s o med as by-p oduc s consis ed mainly o dime s. The sys em wi h excess N-MP p oduced 81 w % oligome s (10), o which 92% we e bu enes. E en he selec i i y o gi e 1-bu ene among hese bu enes was ou s anding wi h 79%. Ob iously, highe bu e ing le els came along wi h lowe isome iza ion a es and, hus, la ge amoun s o α-ole inic dime s we e o med. T iphenylphosphine, which was able o bu e Lewis acidic chlo oalumina e mel s,[34] was also es ed in addi ion o BiPh3 and N-MP o i s abili y o ac i a e he nickel complex in combina ion wi h AlCl3. Al hough AlCl3 dissol ed in CH2Cl2 upon con ac wi h PPh3, he esul ing solu ion was almos inac i e and p oduced no polyme (12). An explana ion o he o ma ion o polyme s compe ing wi h highly selec i e ole in dime iza ion eac ions is gi en in Scheme 2. The diimine ligand wi h i s bulky isop opyl subs i uen s is manda o y o he nickel cen e o polyme ize e hene. Howe e , he Lewis acidic aluminum chlo ide cen e compe es wi h he nickel cen e o he Lewis basic diimine ligand. As soon as he ligand is abs ac ed om he me al cen e , he nickel complex is no longe able o polyme ize e hene. Ins ead, he emaining nickel b omide is a e y e icien dime iza ion ca alys upon ac i a ion.[36] The same beha iou 7 Bu e ed Aluminum Chlo ide as Highly E icien Coca alys o Ole in Dime iza ion and Polyme iza ion Reac ions 115 was obse ed o he con en o highly b anched 2,3-dime hylbu enes in he case o p opene dime iza ion eac ions. As soon as he s e ically demanding icyclohexyl- phosphine ligands a e abs ac ed om he nickel cen e , he o ma ion o 2,3-dime hyl- bu enes is s opped. Scheme 2: Abs ac ion o he diimine ligand o complex 1 by AlCl3. The esul s o he e hene polyme iza ion eac ions also con i med ou heo y ha BiPh3 supp essed he ligand abs ac ion mo e e icien ly han N-MP. In iphenylbismu h based sys ems (8, 11), he polyme yields we e highe han in N-MP bu e ed sys ems (9, 10). Howe e , a e ligand abs ac ion, he N-MP bu e ed sys ems displayed highe selec- i i ies o gi e bu enes. Also, he isome iza ion o 1-bu ene o yield 2-bu enes was educed in less acidic sys ems and wi h highe bu e con en s. These esul s sugges ed ha such nickel based e hene dime iza ion sys ems a e capable o p oducing α-ole ins wi h high selec i i ies. Howe e , subsequen isome iza ion eac ions disguised he eal p oduc dis ibu ions. The ca aly ic esul s indica ed ha he mechanism o hese homogeneous aluminum chlo ide based sys ems was simila o he mechanism we p oposed o nickel ca alyzed ole in dime iza ion eac ions in bu e ed chlo oalumina e ionic liquids.[33] Upon con ac wi h aluminum chlo ide, a nickel halide complex o ms Ni(AlX4)2 (X = Cl, B ) species[37] wi h weakly coo dina ing e ahaloalumina e anions. While s ongly coo dina ing ligands, e.g. biden a e diimines o monoden a e basic phosphines, emain a he ac i e nickel cen e , he weakly coo dina ing [AlX4]– anions can easily be eplaced by ole ins o bu e molecules. Since no alkyla ing agen was p esen in hese sys ems, we also assume ha he ca aly ic cycle s a ed wi h he o ma ion o nickelacyclopen ane.[33] 7 Bu e ed Aluminum Chlo ide as Highly E icien Coca alys o Ole in Dime iza ion and Polyme iza ion Reac ions 122 essel was cooled o 0°C, and he p essu e was slowly eleased. A e eaching ambien empe a u e, he weigh gain o he essel was de e mined, and he p oduc phase was analyzed by gas ch oma og aphy. To de e mine he con en o n-hexenes, 2- me hylpen enes, and 2,3-dime hylbu enes, he p oduc ac ion was hyd ogena ed wi h palladium on ac i a ed ca bon and analyzed by gas ch oma og aphy. Acknowledgemen s Financial suppo by ConocoPhillips, USA, is g a e ully acknowledged. We also hank D . W. K e schme o he HT-GPC measu emen s. M.D. hanks he Eli e Ne wo k o Ba a ia (ENB) wi hin he g adua e p og am “Mac omolecula Science”. 7.4 Re e ences [1] a) K. Ziegle , E. Holzkamp, H. B eil, H. Ma in, Angew. Chem. 1955, 67, 541-547; b) K. Fische , K. Jonas, P. 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[32] H. Schumann, B. C. Wasse mann, B. Heyme , M. Kei sch, F. Gi gsdies, Z. Ano g. Allg. Chem. 2001, 627, 1828-1835. [33] M. Dö e l, H. G. Al , Hea y Me al wi h Hea y Impac : Ole in Dime iza ion Reac ions in T iphenylbismu h Bu e ed Chlo oalumina e Ionic Liquids, o be submi ed. [34] M. Dö e l, P. Thoma, H. G. Al , Facile Syn hesis o new Ca ionic T iphenylphosphine De i a i es and hei Use o P opene Dime iza ion Reac ions in Bu e ed Chlo oalumina e Ionic Liquids, o be submi ed. 7 Bu e ed Aluminum Chlo ide as Highly E icien Coca alys o Ole in Dime iza ion and Polyme iza ion Reac ions 125 [35] H. E. Swi , C.-Y. Wu, US 3622649, 1971. [36] M. Dö e l, H. G. Al , Nickel ca alyzed P opene Dime iza ion Reac ions in BiPh3 bu e ed Chlo oalumina e Ionic Liquids: High Pe o mance wi h uncon en ional Ca ions, o be submi ed. [37] J. B ynes ad, H. L. Yakel, G. P. Smi h, Ino g. Chem. 1970, 9, 686-686. [38] a) R. T. Ca lin, J. S. Wilkes, J. Mol. Ca al. 1990, 63, 125-129; b) W. Ochedzan- Siodlak, B. Sache -Majewska, Eu . Polym. J. 2007, 43, 3688-3694; c) W. Ochedzan-Siodlak, K. Dziubek, D. Siodlak, Eu . Polym. J. 2008, 44, 3608-3614. [39] a) M. Pinhei o, R. Maule , R. de Souza, Mac omol. Rapid Commun. 2001, 22, 425-428; b) V. Lecocq, H. Oli ie -Bou bigou, Oil & Gas Science and Technology - Re . IFP 2007, 62, 761-773. [40] Z. G ubisic, P. Rempp, H. Benoi , Jou nal o Polyme Science Pa B: Polyme Le e s 1967, 5, 753-759. 8 Silica Suppo ed Coca alys s o Ole in Dime iza ion and Polyme iza ion Reac ions wi h Nickel Complexes 126 8 Silica Suppo ed Coca alys s o Ole in Dime iza ion and Polyme iza ion Reac ions wi h Nickel Complexes Ma hias Dö e l[a] and Helmu G. Al *[a] [a] Leh s uhl ü Ano ganische Chemie II, Uni e si ä ss aße 30, NW I, 95440 Bay eu h, Ge many. E-mail: [email p o ec ed] Keywo ds: he e ogeneous ca alysis, nickel, dime iza ion, polyme iza ion, ionic liquids Manusc ip o be submi ed Abs ac : We de eloped a new bu e ed silica based Lewis acid coca alys o ole in dime iza ion and polyme iza ion eac ions wi h nickel complexes. The Lewis acidi ies o E AlCl2 and E 2AlCl modi ied silicas we e adjus ed by he addi ion o BiPh3 o N- me hylpy ole bu e s. The bu e ed he e ogeneous coca alys s we e success ully employed o ac i a e nickel complexes o selec i e p opene dime iza ion eac ions o gi e 91% dime s. Bu e addi ion also educed he a e o ligand abs ac ion om he ca aly ically ac i e nickel cen e . In combina ion wi h a nickel diimine complex, e hene was polyme ized o gi e 69 w % polye hylene and 31 w % oligome s. The polye hylene displayed a molecula weigh o 154 kg/mol and a PDI o 3.26. The oligome s consis ed o 93% bu enes, 46% he eo being 1-bu ene. Fu he mo e, iphenylbismu h bu e ed 8 Silica Suppo ed Coca alys s o Ole in Dime iza ion and Polyme iza ion Reac ions wi h Nickel Complexes 127 Lewis acidic chlo oalumina e ionic liquids we e coa ed on su ace modi ied silica o yield a suppo ed ionic liquid phase (SILP) sys em. Dime selec i i ies o up o 94% we e ob ained wi h he SILP sys em in nickel ca alyzed p opene dime iza ion eac ions. The newly de eloped silica based coca alys s p o ide p omising new ole in dime iza ion sys ems sui able o ixed bed applica ions. 8.1 In oduc ion Mos o he majo me al complex ca alyzed ole in con e sion p ocesses including hyd o o myla ion, me a hesis, dime iza ion, and polyme iza ion eac ions we e disco e ed in homogeneous solu ion. Howe e , all o hese p ocesses we e con e ed o biphasic[1] o he e ogeneous[2] sys ems in o de o imp o e he economics o hei applica ion in la ge scale indus ial p ocesses. Ole in polyme iza ion eac ions, which yield solid p oduc s, ha e o be pe o med in slu y, bulk-monome , o gas-phase p ocesses o la ge capaci ies.[2d] The e o e, he ca alys s a e usually suppo ed on an ino ganic ca ie o p e en eac o ouling and o gua an ee uni o m polyme pa icle sizes.[2c, 2d] Fo example, he old he e ogeneous Union Ca bide (ch omocene/silica) and Phillips (C O3/silica) ca alys s a e s ill esponsible o abou one hi d o he global HDPE p oduc ion.[3] Fo ole in dime iza ion eac ions, which yield gaseous o liquid p oduc s, he e ogeneous ca alys sys ems a e ad an ageous o ixed bed eac o s because he do no equi e expensi e echnologies. The ole in s eam passes he solid ca alys , which is immobilized in he eac o . The e a e se e al di e en app oaches o suppo me al complexes, which ha e o be ac i a ed by aluminum based coca alys s o ole in dime iza ion o polyme iza ion eac ions. The mos common me hod is he imp egna ion o an ino ganic suppo ma e ial wi h alkylaluminum compounds like me hylaluminoxane (MAO) o ime hyl- aluminum (TMA) and a me al complex.[2c, 2d, 4] Howe e , he high p ices o MAO and TMA es ic hei use o he p oduc ion o aluable high pe o mance polyme s. The well known i anium chlo ide based Ziegle -Na a ca alys s suppo ed on MgCl2 also belong o his class.[3a, 5] 8 Silica Suppo ed Coca alys s o Ole in Dime iza ion and Polyme iza ion Reac ions wi h Nickel Complexes 128 A second possibili y is o connec me al complexes co alen ly o a he e ogeneous suppo .[6] Howe e , he a achmen o suppo ma e ials equi es changes in he ligand s uc u e and inc eased syn he ic e o s. Lewis acidic ino ganic oxide ma e ials p o ide an al e na i e o he abo e men ioned sys ems. McDaniel e al. de eloped a no el coca alys sys em o me allocene complexes based on alkylaluminum compounds and solid acids.[7] The su ace o ino ganic oxides was modi ied by high empe a u e ea men wi h chlo ina ed o luo i- na ed subs a es. In combina ion wi h ie hylaluminum, hese solid Lewis acids a e able o ac i a e me allocene complexes o e hene polyme iza ion eac ions. This indus ial esea ch o Che onPhillips Chemical[7] showed ha i is desi able o de elop he e o- geneous coca alys s, which can easily be syn hesized, s o ed and used o ac i a e common me al complexes easible o ole in dime iza ion and polyme iza ion eac ions. A lo o esea ch has al eady been done on he su ace modi ica ion o ino ganic oxide ma e ials. In pa icula , hyd oxyl g oups loca ed a silica su aces[8] can be modi ied wi h eac i e aluminum compounds o yield s ong he e ogeneous Lewis acids. The s onges Lewis acid si es a e ob ained by ea ing silica wi h ei he AlCl3[9] o elease HCl o wi h E AlCl2[10] o elease e hane. In he p esence o bo h Al–Cl and Al–C bonds he la e p e e en ially eac .[11] These ma e ials ca alyze c acking, disp opo iona ion, o isome iza ion o alkanes as well as ca ionic oligome iza ion eac ions o ole ins.[10a] The acid s eng h o such g a ed aluminum species usually inc eases wi h mo e halogen a oms being a ached o he aluminum cen e .[12] Since SiO–AlCl2 su ace g oups ini ia e he abo e men ioned ca ionic ole in oligome iza ion eac ions, hey canno be applied as coca alys s o me al complex ca alyzed ole in dime iza ion o polyme iza ion eac ions. Fi s , he Lewis acidi ies o such s ong solid acids ha e o be educed o a le el, a which said uncon olled ca ionic ole in oligome iza ion eac ions do no ake place. We iden i ied new s a egies o o e come his p oblem. In a ecen pape , we desc ibed no el coca alys s o nickel ca alyzed ole in dime iza ion and polyme iza ion eac ions based on a combina ion o aluminum chlo ide and weak Lewis bases such as N- me hylpy ole o iphenylbismu h.[13] The weak Lewis bases bu e ed he high Lewis acidi y o aluminum chlo ide and kep i in solu ion by o ming a weak adduc . Such o ganic bu e s we e p e iously used by Wasse scheid e al.[14] and ou g oup[15] o 8 Silica Suppo ed Coca alys s o Ole in Dime iza ion and Polyme iza ion Reac ions wi h Nickel Complexes 129 educe he “la en acidi y”[16] o Lewis acidic chlo oalumina e ionic liquids. The bu e ed chlo oalumina e mel s we e employed o ac i a e nickel complexes o selec i e dime iza ion eac ions o α-ole ins. Thus, we expec ed ha he addi ion o hese bu e ing subs ances would con ol he Lewis acidi ies o E AlCl2 modi ied solid acids in a simila manne . Nickel based sys ems a e pa icula ly in e es ing because hey can be ac i a ed wi h cheap E 2AlCl o E AlCl2 coca alys s. Depending on he ligand s uc u e, hey we e ound o ca alyze bo h selec i e ole in dime iza ion[17] o polyme iza ion[18] eac ions. The second app oach elied on silica ea ed wi h excess E 2AlCl. Since he Lewis acidi y o he su ace aluminum species dec eases wi h a dec easing numbe o halogens,[12] he subs i u ion o SiO–AlCl2 g oups wi h SiO–AlE Cl should come along wi h educed Lewis acidi ies. Because E 2AlCl can eac wi h bo h e hyl g oups o elease wo molecules e hane pe molecule E 2AlCl,[11] he use o excess E 2AlCl should a ou he o ma ion o SiO–AlE Cl species. Upon bu e ing wi h N-me hylpy ole and BiPh3, hese SiO–AlE Cl species we e expec ed o ac i a e nickel complexes o selec i e ole in dime iza ion and polyme iza ion eac ions. Fu he mo e, E AlCl2 modi ied silica should p o ide a sui able suppo ma e ial o bu e ed chlo oalumina e ionic liquids o ob ain pseudo he e ogeneous suppo ed ionic liquid phase[19] (SILP) dime iza ion sys ems. 8.2 Resul s and Discussion Bu e ed Silica Suppo ed E AlCl2 as Coca alys o He e ogeneous Nickel Ca alyzed P opene Dime iza ion Reac ions Fo all expe imen s, Da ica ® SI1102 silica wi h a pa icle size o 0.4 – 0.8 mm om W.R. G ace & Co. was used. I has a su ace a ea o 311 m2/g, a po e olume o 1.12 cm3/g and a po e diame e o 144 Å. The silica was o en d ied a 350°C p io o all manipula ions. In a p elimina y expe imen , ea men o dehyd a ed silica wi h excess E AlCl2 esul ed in a weigh gain o abou 15.7%. Unde he app oxima ion ha each molecule o E AlCl2 eac ed wi h only one su ace OH g oup o elease e hane,[11] he densi y o eac i e su ace OH g oups was calcula ed o be 1.6 mmol/g. 8 Silica Suppo ed Coca alys s o Ole in Dime iza ion and Polyme iza ion Reac ions wi h Nickel Complexes 130 Figu e 1: Ca alys p ecu so s used o p opene dime iza ion (A, B) and e hene poly- me iza ion eac ions (C). Scheme 1 shows he su ace modi ica ion o dehyd a ed silica I wi h E AlCl2 and E 2AlCl o gi e silica II and III, espec i ely. Fi s , he highly acidic E AlCl2 modi ied silica II was bu e ed wi h N-me hylpy ole o BiPh3 (Table 1) and applied as coca alys o nickel ca alyzed p opene dime iza ion eac ions wi h complex A (Figu e 1). Bo h sys ems we e es ed in ba ch expe imen s wi h liquid p opene. In o de no o des oy he silica s uc u e, s i ing was a oided. T iphenylbismu h was dispe sed om a me hylene chlo ide solu ion, which was emo ed a e wa ds. I s high molecula weigh equi ed educed loadings. In he case o N-me hylpy ole, a cosol en had o be applied o ob ain a homogeneous dis ibu ion o he ola ile he e ocyclic bu e . In bo h expe imen s, dime s we e p oduced wi h high ac i i ies. Also, he dime ac ion consis ed o ema kable amoun s o 60% (1) and 47% (2) o aluable 2,3-dime hyl- bu enes. Wi hou he bu e , iscous oils consis ing o highe oligome s om ca ionic p opene oligome iza ion eac ions we e ob ained. Howe e , he selec i i ies o gi e dime s we e poo . Also, he N-me hylpy ole bu e ed sys em 2 was inac i e in a subsequen expe imen . Consequen ly, he Lewis acidi y was s ill oo high. Highe amoun s o bu e could u he educe he acidi y. Howe e , huge amoun s o he hea y BiPh3 would be necessa y, while N-me hylpy ole sys ems deac i a ed quickly. 8 Silica Suppo ed Coca alys s o Ole in Dime iza ion and Polyme iza ion Reac ions wi h Nickel Complexes 131 Scheme 1: Su ace modi ica ion o dehyd a ed silica (I) wi h e hylaluminum dichlo ide (II) and die hylaluminum chlo ide (III) and bu e ing o he Lewis acidic su ace aluminum species. 8 Silica Suppo ed Coca alys s o Ole in Dime iza ion and Polyme iza ion Reac ions wi h Nickel Complexes 138 he dime yield inc eased o 90% (14), which was simila o he unsuppo ed sys em. Wi h a educed loading o 80 w %, mainly highe oligome s we e ob ained (17). Fo his sys em loaded wi h 80 w % bu e ed [BMIM]+[Al2Cl7]− ionic liquid, a bu e con en o one equi alen was necessa y o aise he dime selec i i y o 90% again (18). T iphenylbismu h equalled abou 37 w % o he o al weigh in [BMIM]+[Al2Cl7]− / BiPh3 = 0.60 sys ems. Wi h one equi alen o bu e , e en 50 w % o he ca aly ically ac i e mel consis ed o BiPh3. The e o e, small changes in e ms o loading o composi ion led o d as ic changes in pe o mance. Fo ionic liquids de i ed om ca ions wi h lowe molecula weigh s, lowe loadings would ce ainly be su icien . A sys em wi h a less acidic composi ion o [AlCl3] / [BMIMCl] = 1.50 and 0.60 equi alen s o BiPh3 yielded 94% dime s in he i s expe imen (19a). Then, he p oduc s we e decan ed, and he ba ch expe imen was epea ed. In ou subsequen ca aly ic uns, he sys em main ained a dime selec i i y o a ound 90% (19b – e) be o e i d opped signi ican ly. All sys ems displayed low p oduc i i ies compa ed o hei biphasic analogues.[15c] Howe e , no s i ing was applied in o de no o des oy he silica s uc u e. Wi h an imp o ed mixing, he p oduc i i ies could ce ainly be inc eased. The e e ence complex B had no e ec on he b anching o he hexene dime s,[15a] all C6 ac ions consis ed o (± 2%) 25% n-hexenes, 69% 2-me hylpen enes, and 6% 2,3-dime hylbu enes. This co ela ed o he ypical p oduc dis ibu ion ob ained om ligand ee nickel sal s.[14d] T iphenylbismu h bu e ed chlo oalumina e ionic liquids suppo ed on su ace modi ied silica p o ide no el he e ogeneous coca alys sys ems o nickel ca alyzed ole in dime iza ion eac ions. I ionic liquids based on amine hyd ochlo ides a e used, bo h he bu e and he amine can be eco e ed by a simple acid base ex ac ion.[15a] Especially he applica ion o gas phase e hene dime iza ion eac ions is e y p omising since no leaching o ei he he ionic liquid o he bu e can occu . Fu he mo e, alkylaluminum ee ionic liquid composi ions a e less sensi i e o oxygen o pola impu i ies. Conclusion We de eloped a new class o bu e ed solid acid coca alys s o nickel ca alyzed ole in dime iza ion and polyme iza ion eac ions. The Lewis acidi y o E AlCl2 modi ied silica was educed by he addi ion o BiPh3 o N-me hylpy ole bu e s. Uncon olled ca ionic 8 Silica Suppo ed Coca alys s o Ole in Dime iza ion and Polyme iza ion Reac ions wi h Nickel Complexes 139 ole in oligome iza ion eac ions, which usually occu in he p esence o SiO–AlCl2 species, we e supp essed by he dono -accep o in e ac ions. Silica modi ica ion wi h E 2AlCl ins ead o E AlCl2 yielded solid coca alys s wi h educed Lewis acidi ies. The coca alys s we e success ully employed o ac i a e a nickel complex o selec i e p opene dime iza ion eac ions o gi e 84% dime s. The addi ion o small amoun s o N-me hylpy ole o he ca alys suspension inc eased he dime selec i i y up o 91%. Fu he mo e, he addi ion o ei he BiPh3 o N-me hylpy ole hinde ed he ligand abs ac ion om he ca aly ically ac i e me al cen e . The same E 2AlCl modi ied silica wi h addi ional N-me hylpy ole bu e was used o ac i a e a nickel diimine complex o e hene polyme iza ion eac ions o gi e 69 w % polye hylene and 31 w % oligome s. Rema kably, 93% o he oligome s we e bu enes wi h 46% he eo being 1-bu ene. The polye hylene was pa ially c ys alline and displayed a molecula weigh o 154 kg/mol wi h a PDI o 3.26. Bu e ed, su ace modi ied silicas p o ide a p omising new class o coca alys s o he- e ogeneous nickel ca alyzed ole in dime iza ion and polyme iza ion eac ions. Su ace modi ica ion was accomplished in one s ep wi h cheap E 2AlCl. The he e ogeneous coca alys s we e able o ac i a e common nickel complexes and can be applied in ixed bed ubes o ole in dime iza ion eac ions. Selec i i y con ol could be achie ed by he addi ion o small amoun s o an N-me hylpy ole bu e o he ole in eed s eam. In combina ion wi h nickel based polyme iza ion ca alys s, he same sys ems could be applied in slu y e hene polyme iza ion eac ions. Ou esul s indica ed ha he ca aly ically ac i e species we e immobilized on he silica su ace. Finally, BiPh3 bu e ed Lewis acidic chlo oalumina e ionic liquids we e coa ed on su ace modi ied silicas o yield suppo ed ionic liquid phase (SILP) sys ems o nickel ca alyzed p opene dime iza ion eac ions. Dime selec i i ies up o 94% we e ob ained wi h he SILP sys ems. In con as o he abo e men ioned bu e ed su ace modi ied silica coca alys s, no ex e nal bu e had o be added. The BiPh3 bu e was immobilized in he ionic liquid. Such SILP sys ems a e p edes ined o gas phase e hene dime iza ion eac ions since no leaching can occu in gas phase eac ions. 8 Silica Suppo ed Coca alys s o Ole in Dime iza ion and Polyme iza ion Reac ions wi h Nickel Complexes 140 8.3 Expe imen al Sec ion Gene al In o ma ion All chemical manipula ions we e ca ied ou using s anda d Schlenk echniques unde a gon a mosphe e. n-Hep ane and n-pen ane we e dis illed om Na/K alloy unde ine a mosphe e. Me hylene chlo ide was dis illed in wo s eps om P4O10 and CaH2, oluene om P4O10 and Na/K alloy. The p oduc s o he dime iza ion expe imen s we e cha ac e ized by gas ch oma og aphy (Agilen 6850) and GC-MS (FOCUS DSQ™ The mo Scien i ic). Di e en ial scanning calo ime y expe imen s we e conduc ed a a hea ing a e o 10°C/min unde N2 a mosphe e wi h a Pe kin-Elme Diamond DSC, calib a ed wi h indium. The endo he mic maximum o he second hea ing cycle was aken as Tm. The molecula weigh s (Mw/Mn) o he e hylene polyme s we e de e mined by gel pe mea ion ch oma og aphy on a Polyme Labo a o ies L d. (PL-GPC220) ch oma og aph a 150°C using 1,2,4- ichlo obenzene as he mobile phase. The sample was p epa ed by dissol ing he polyme (0.1% weigh / olume) in he mobile phase sol en in an ex e nal o en and was un wi hou il a ion. The molecula weigh was e e enced o polys y ene (Mw = 510 – 3100000 g/mol) s anda ds using he uni e sal calib a ion me hod.[25] The epo ed alues a e he a e age o a leas wo independen de e mina ions. E hene (99.9%) and p opene (99.3%) we e pu chased om Riessne Gase, Lich en els, and we e d ied o e a column packed wi h P4O10. E AlCl2 (1.8 N in oluene) and E 2AlCl (0.9 N in oluene) we e pu chased om Ac os. T iphenylphosphine and iphenylbismu h we e pu chased om ABCR. N-Me hylpy ole, 1-bu yl-3- me hylimidazolium e achlo oalumina e (BASF), AlCl3 (Reagen Plus®), and (PPh3)2NiCl2 we e pu chased om Sigma-Ald ich and used as ecei ed. Complexes A[15a] and C[18] we e syn hesized acco ding o he li e a u e. P epa a ion o he Su ace Modi ied Silicas II and III Fo all expe imen s, Da ica ® SI1102 silica wi h a pa icle size o 0.4 – 0.8 mm om W.R. G ace & Co. was used. I has a su ace a ea o 311 m2/g, a po e olume o 1.12 cm3/g and a po e diame e o 144 Å. P io o all manipula ions, he silica was dehyd a ed o 4 hou s a 350°C o gi e silica I. The dehyd a ed silica I was illed in o a glass i unde a gon coun e low, and hal o i s olume was co e ed wi h oluene. Fo 8 Silica Suppo ed Coca alys s o Ole in Dime iza ion and Polyme iza ion Reac ions wi h Nickel Complexes 141 silica II, 2 mmol E AlCl2 (1.8 N in oluene) pe g, o silica III 3 mmol E 2AlCl (0.9 N in oluene) pe g we e added. The i was equipped wi h a p essu e al e, and he suspension was s i ed wi h a spa ula once in a while. The mix u e was le s anding o e nigh un il no mo e bubbles could be obse ed. The modi ied silica was washed h ee imes wi h oluene and n-pen ane, d ied in acuo, and s o ed in a Schlenk ube. P epa a ion o Bu e ed Su ace Modi ied Silica Coca alys Composi ions The co esponding amoun o su ace modi ied silica was weighed in o a glass au ocla e. Fo BiPh3 bu e ed sys ems (1, 4), he silica was co e ed wi h CH2Cl2. Then, he bu e was added, and he au ocla e was gy a ed. To he CH2Cl2 suspension he ca alys p ecu so A was added om a s ock solu ion in CH2Cl2. Subsequen ly, he me hylene chlo ide was emo ed in acuo o yield he he e ogeneous BiPh3 bu e ed p opene dime iza ion sys em. Fo he unbu e ed expe imen (3), he same p ocedu e was applied wi hou he addi ion o BiPh3. Fo N-me hylpy ole bu e ed sys ems (2, 5 – 9), he silica was co e ed wi h n-hep ane o oluene. The co esponding amoun o N-me hylpy ole was added o he suspension. Fo he expe imen s in Table 2, a dilu ion se ies o N-me hylpy ole in n-hep ane and oluene was pe o med. The au ocla e was gy a ed and le s anding o a ew minu es. Then, he solid ca alys p ecu so A was added. A e i had dissol ed, he sys em was used o he e ogeneous N-me hylpy ole bu e ed p opene dime iza ion eac ions. P epa a ion o T iphenylbismu h Bu e ed 1-Bu yl-3-me hylimidazolium Chlo oalumina e Ionic Liquid Suppo ed on Silica AlCl3 was dissol ed in comme cial 1-bu yl-3-me hylimidazolium e achlo oalumina e o ob ain he desi ed composi ions. The co esponding amoun s o ionic liquid and BiPh3 we e added o a glass au ocla e and mixed un il a homogeneous solu ion was ob ained. Subsequen ly, he bu e ed ionic liquid was dilu ed wi h CH2Cl2 and silica was added ollowed by he addi ion o ca alys p ecu so B. Upon i s dissolu ion, he sol en was emo ed in acuo o yield a ee lowing g anula powde . 8 Silica Suppo ed Coca alys s o Ole in Dime iza ion and Polyme iza ion Reac ions wi h Nickel Complexes 142 P ocedu e o P opene Dime iza ion Reac ions wi h He e ogeneous Ca alys s (Expe imen s 1 – 9, 11 – 19) Fo all p opene dime iza ion eac ions, a 300 ml glass au ocla e was used. No s i ing was applied in o de no o des oy he silica s uc u e and o gua an ee iden ical condi ions. The glass essel was kep in a d ying o en a 150°C o se e al hou s be o e an expe imen . An au ocla e con aining he he e ogeneous ca alys composi ion was cooled, and acuum was applied. Subsequen ly, p opene (50 ml) was condensed in o he glass au ocla e by liquid ni ogen cooling. Then, he au ocla e was placed in a me al box o sa e y easons, and he empe a u e was egula ed by an ex e nal wa e ba h. A e he expe imen , he p essu e was slowly eleased by opening a al e. A e eaching ambien empe a u e, he weigh di e ence o he au ocla e was de e mined, and he p oduc phase was analyzed by gas ch oma og aphy. To de e mine he con en o n- hexenes, 2-me hylpen enes, and 2,3-dime hylbu enes, he p oduc ac ion was hyd o- gena ed wi h palladium on ac i a ed ca bon, and he p oduc s we e analyzed by gas ch oma og aphy. In he case o expe imen s 3 and 19, he p oduc phase was decan ed, analyzed by gas ch oma og aphy, and he expe imen was epea ed. P ocedu e o E hene Polyme iza ion Reac ions wi h an N-Me hylpy ole Bu e ed Su ace Modi ied Silica Coca alys (Expe imen 10) Fo he e hene polyme iza ion eac ion, a s i ed 300 ml Pa s ainless s eel au ocla e was used. The s eel essel was kep in a d ying o en a 150°C o se e al hou s be o e an expe imen , and i was illed wi h a gon. The au ocla e was cooled o 0°C wi h an ice ba h. Then, a solu ion o N-me hylpy ole (0.05 ml) in oluene (50 ml) was added o he eac o ollowed by he addi ion o su ace modi ied silica III (12.60 g). Complex C (18.0 mg) was suspended in oluene (20 ml), and he suspension was illed in o he eac o . The sys em was pu unde acuum, and he empe a u e was aised o 40°C. Then, a e 5 minu es o s i ing, an e hene p essu e o 10 ba was applied. Cooling o he exo- he mic eac ion was achie ed manually by an ice ba h. A e he expe imen , he essel was quickly cooled o –20°C. The p essu e was eleased, he weigh di e ence o he essel was de e mined (23.24 g), and a cooled sample was di ec ly analyzed by gas ch oma og aphy. The silica / polye hylene composi e ma e ial was sepa a ed by il a- ion, washed se e al imes wi h ace one and wa e , and i s weigh was de e mined a e 8 Silica Suppo ed Coca alys s o Ole in Dime iza ion and Polyme iza ion Reac ions wi h Nickel Complexes 143 d ying (28.62 g silica + polye hylene). A sample o he composi e ma e ial was s i ed o 2 hou s in 1,2,4- ichlo obenzene a 120°C o dissol e he polye hylene. The iscous solu ion was quickly il e ed, and he polyme was p ecipi a ed by he addi ion o ace- one. The pu e polye hylene sample ob ained a e il a ion and d ying was analyzed by di e en ial scanning calo ime y and high empe a u e gel pe mea ion ch oma og aphy. Acknowledgemen s Financial suppo by ConocoPhillips, USA, is g a e ully acknowledged. We also hank D . W. K e schme o he HT-GPC measu emen . 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Benoi , Jou nal o Polyme Science Pa B: Polyme Le e s 1967, 5, 753-759. 9 Solubili y Beha iou o TiCl4, Z Cl4, and H Cl4 in Chlo oalumina e Ionic Liquids 146 9 Solubili y Beha iou o TiCl4, Z Cl4, and H Cl4 in Chlo oalumina e Ionic Liquids Ma hias Dö e l[a], Isabelle Haas[a] and Helmu G. Al *[a] [a] Leh s uhl ü Ano ganische Chemie II, Uni e si ä ss aße 30, NW I, 95440 Bay eu h, Ge many. E-mail: [email p o ec ed] Keywo ds: ha nium, zi conium, i anium, chlo oalumina es, ionic liquids Manusc ip o be submi ed Abs ac : The solubili y o NbCl5, TaCl5, TiCl4, Z Cl4, and H Cl4 in neu al [BMIM][AlCl4] (BMIM = 1-bu yl-3-me hylimidazolium) was de e mined. While TiCl4 was immiscible wi h he neu al ionic liquid, 0.80 mola equi alen s o Z Cl4 and s oichiome ic amoun s o H Cl4 dissol ed in he mel a ambien empe a u e. The c ys al s uc u es and he uni cell pa ame e s o [Ti2Cl10][BMIM]2, [Z 2Cl10][BMIM]2, and [H 2Cl9][PhNMe3] we e de e mined. [Ti2Cl10][BMIM]2, and [Z 2Cl10][BMIM]2 we e c ys allized om basic chlo o- alumina e mel s. Wi h a ime hylanilinium ca ion, [H 2Cl9][PhNMe3] c ys allized om an equimola composi ion o PhNMe3Cl, AlCl3, and H Cl4 abs ac ing a chlo ide ligand om [AlCl4]– o gi e highly Lewis acidic [Al2Cl7]– anions. 9.1 In oduc ion Abou 30 yea s ago, Wilkes e al. and Os e young e al. epo ed he i s oom empe a u e ionic liquids based on aluminum chlo ide.[1] In combina ion wi h o ganic ca ions like N-alkylpy idinium o 1-alkyl-3-me hylimidazolium chlo ide, AlCl3 o med liquids a ambien empe a u e o e a wide ange o composi ions. Fo example, a 9 Solubili y Beha iou o TiCl4, Z Cl4, and H Cl4 in Chlo oalumina e Ionic Liquids 147 mix u e o 1-e hyl-3-me hylimidazolium chlo ide wi h wo equi alen s o AlCl3 was s ill ound o be a liquid a – 80°C.[2] The Lewis acidi ies o such chlo oalumina e ionic liquids a e de e mined by he a io o AlCl3 o o ganic chlo ide sal .[3] In mix u es con aining excess chlo ide sal , he [AlCl4]– anion is he dominan aluminum species.[3] Wi h inc easing AlCl3 con en , he equilib ium is shi ed owa ds [Al2Cl7]– species.[1a, 1c, 4] The p esence o [Al3Cl10]– was also de ec ed in highly acidic mel s.[5] Usually, he mel ing poin s display a minimum wi h a a io AlCl3 / halide sal = 0.33 o 0.67, while a local maximum is obse ed o neu al composi ions.[2a, 6] La e , chlo oalumina e ionic liquids we e also employed as sol en s o o he me al sal s.[7] Especially basic mel s wi h ee chlo ide ligands dissol ed a a ie y o me al halides o gi e anionic chlo ome alla e complexes.[8] Acidic chlo oalumina e mel s we e used o dissol e small amoun s o i anium e achlo ide. The mix u es we e used o elec ochemical oxida ion and me al deposi ion eac ions.[9] Ti anium and zi conium e achlo ide addi i es in acidic chlo oalumina e mel s we e epo ed o p omo e alkyla ion eac ions o isopa a ins wi h ole ins.[10] Imidazolium ca ions we e also applied o he o ma ion o ionic liquids wi h a a ie y o o he me al chlo ides o he han aluminum chlo ide.[11] Howe e , he quan i a i e solubili y beha iou o Lewis acidic me al chlo ides in neu al e achlo oalumina e mel s has no been in es iga ed ye . 9.2 Resul s and Discussion Ca ionic P opene Oligome iza ion Reac ions Ini ia ed by Mix u es o Me al Chlo ides and [BMIM][AlCl4] We we e in e es ed in new Lewis acidic ionic liquid composi ions, which ca alyze eac ions ypical o acidic chlo oalumina e ionic liquids like ca ionic oligome iza ion o ole ins,[12] isome iza ion[13] and c acking[14] eac ions o sa u a ed alkanes, o F iedel C a s alkyla ion eac ions.[15] The e o e, we chose he comme cially a ailable 1-bu yl-3-me hylimidazolium (BMIM) e achlo oalumina e as s anda d sol en o p elimina y expe imen s wi h di e en me al chlo ides. This neu al ionic liquid i sel did no ca alyze ca ionic ole in oligo-