Turning waste into resources. Efficient synthesis of biopolyurethanes from used cooking oils and CO2

Contents lists available at ScienceDirect Journal of CO2 Utilization journal homepage: www.elsevier.com/locate/cviu Turning Waste into Resources. Efficient Synthesis of Biopolyurethanes from Used Cooking Oils and CO2 Francisca Werlinger,a,b María P. Caballero,c Oleksandra S. Trofymchuk,a Mario E. Flores,b Ignacio Moreno-Villoslada,b Felipe de la Cruz-Martínez,c José Antonio CastroOsma,c Juan Tejeda,c,* Javier Martínez,b,* Agustín Lara-Sánchezc,* aFacultad de Ciencias Químicas y Farmacéuticas, Departamento de Química Orgánica y Fisicoquímica, Universidad de Chile, Santiago 8380492, Chile. bInstituto de Ciencias Químicas, Facultad de Ciencias Isla Teja Universidad Austral de Chile 5090000, Valdivia, Chile. cUniversidad de Castilla-La Mancha, Departamento de Química Inorgánica Orgánica y Bioquímica-Centro de Innovación en Química Avanzada (ORFEO-CINQA) Facultad de Ciencias y Tecnologías Químicas and Instituto Regional de Investigación Científica Aplicada-IRICA, 13071, Ciudad Real (Spain) Abstract: The coupling reaction of carbon dioxide and highly-substituted epoxides derived from renewable resources such as fatty acids and waste vegetable oils (cooking oils derived from olive and sunflower) leads to the synthesis of new bio-derived cyclic carbonates using efficient metal-free bifunctional organocatalysts under mild and solvent-free reaction conditions. Once cyclic carbonates derived from biobased sources were synthesized, the design of non-isocyanate polyurethanes (NIPUs) with different chemical structures was investigated by their reaction with a broad substrate scope of diamines. The NIPUs materials were characterized by spectroscopic techniques (NMR and IR) and their molecular weights and polydispersities were determined by GPC studies. Finally, thermal properties of the polymers were studied by DSC and TGA analyses. Dedicated to Professor Michael North on the occasion of his retirement. © 2017 Elsevier Inc. All rights reserved. Keywords: CO2; non-isocyanate polyurethanes (NIPUs); cyclic carbonates; organocatalysts; epoxides. 1. Introduction Carbon dioxide (CO2) has become the principal anthropogenic gas responsible for global warming [1]. The concentration of CO2 in the atmosphere has been continuously increasing since the Industrial Revolution from 280 to 420.4 ppm, principally due to the use of fossil fuels [2]. This fact is of great concern to society, therefore greener and more sustainable synthetic processes and methodologies respectful with the environment should be developed to accomplish the “Twelve Principles of Green Chemistry” [3]. As a result, it is necessary to focus on the chemical fixation and transformation of CO2 into value-added products with the aim to reduce its concentration in the atmosphere which would help to mitigate climate change [4,5]. CO2 is a non-toxic, non-flammable, and renewable C1 2 Author name /Journal of CO2 Utilization 000 (2017) 000–000 resource that can be used as starting material for the preparation of a wide variety of organic molecules such as methanol, urea, and salicylic acid, among others.[4,6] Nevertheless, the reactivity of CO2 is quite hampered because of its thermodynamic stability, which means that the use of high pressures and temperatures is required, for these reasons, it is highly desirable to carry out the synthesis of novel effective catalytic systems to overcome the elevated energy barriers related with reactions of CO2 [7–9]. In that sense, the catalytic formation of cyclic carbonates by cycloaddition of CO2 into epoxides is one of the most promising reactions since it is a 100% atom-economy reaction in which CO2 is used as efficient feedstock [10]. The industrial preparation of ethylene or propylene carbonates catalyzed by quaternary ammonium salts has been performed since the 1950s, however, it requires high temperatures and high CO2 pressures [11]. The 5-membered ring cyclic carbonates, which have noteworthy properties such as high solubility, low toxicity, and low vapor pressure [12], were broadly used as polar aprotic solvents, monomers for the production of polymers, in electrolyte batteries, to mention some applications [13–15]. A huge variety of metal catalysts [16–18], organocatalysts [19–24], metal organic framework (MOFs) [25–29], and ionic liquids,[30–32] among others, have been recently reported for the obtention of cyclic carbonates from epoxides and CO2. Lately, scientific groups have centered their efforts towards the preparation of bio-based cyclic carbonates obtained from renewable starting materials since waste generation has grown enormously in the last few years, thus it is necessary to develop new tactics to reduce waste production and increment residue valorization [33–38]. Among the produced waste, residues derived from vegetable oils, which are mainly generated in homes, restaurants, and hotels, are the most plentiful food residue, therefore used vegetable oils can get a “second chance”, firstly for food purposes and then for disposal. It is estimated that around 67 million tons per year of waste vegetable oils (WVOs) are generated worldwide [39,40], and normally WVOs are dumped in ocean or rivers, producing significant environmental complications. For these reasons, it must be priority to find new ways to recycle and reuse these WVOs. It should be highlighting that WVOs have the potential to be a renewable resource for the preparation of high value-added products such biodiesel [41–43], soap [44], or cyclic carbonates [19,45–47]. In particular, carbonated vegetable oils (CVOs) could be synthesized by the reaction between epoxidized vegetable oils (EVOs) derived from WVOs and CO2 (Scheme 1a) [19,45–47]. EVOs can be easily prepared by epoxidation of the double bonds present in the triglyceride units [48], which allows vegetable oils to be chemically transformed and increase their potential applications. Furthermore, CVOs have gain huge relevance since they have been used for the synthesis of non-isocyanate polyurethanes (NIPUs) by their reaction with diamines (Scheme 1b) [45,49–57]. These polymers could have potential applications in biomedicine, industrial coating, foams and adhesive [45, 49−57] Scheme 1. Synthetic routes for the formation of CVOs (a) and NIPUs (b). Metal-free organocatalysts have received special attention and could be an interesting alternative to metal compounds since these catalysts are generally prepared in larger amounts. Hydrogen-bond donors (HBDs) Author name / Journal of CO2 Utilization 000 (2017) 000–000 3 organocatalysts have been widely used for the preparation of cyclic carbonates since the presence of proton-containing groups, such as, −COOH, −OH, or −NHhave the ability to activate the epoxide ring through the formation of hydrogen bonds, enabling its opening by the attack of a nucleophile. D’Elia et al. studied the relation between the catalytic activity of the hydroxyl group of the HBDs and their Brønsted acidity in the reaction of CO2 with epichlorohydrin discovering that an elevated Brønsted acidity had a positive effect on hydrogen bond formation facilitating the ring opening of the epoxide, although, it slowed down the release of cyclic carbonate in the cyclization stage [58]. Therefore, the principal challenge will consist in designing HBDs organocatalysts with adequate Brønsted acidity. These catalysts have exhibited excellent catalytic activities for the cyclic carbonate formation as a bifunctional [19,20,59–64] or binary [23,65,66] catalytic systems. In this context, HBDs catalysts based on protic organic salts containing -COOH, -OH, or -NHgroups and a nucleophilic counterion are exceptional candidates to act as a bifunctional organocatalysts for the cycloaddition of CO2 and epoxides. Related to that, organocatalysts based on salts of N-heterocycles have proven to be efficient for the preparation of cyclic carbonates [60,67,68]. Kühn et al reported through DFT calculations and experimental results that the presence of -OH groups in the bisimidazolium salts performed a positive effect on the catalytic activity of these organocatalysts [69]. Additionally, this fact was also observed by our research group in the development of hydroxy-containing imidazole salts which were exceptional bifunctional organocatalysts for the synthesis of a broad variety of cyclic carbonates [20]. An iodide imidazole-based organocatalyst derived from this family of compounds was able to carry out a set of carbonated vegetable oils from WVOs which could be employed as potential bio-derived feedstock in different chemical processes [19,45]. It is important to mention that this family of organocatalysts has not only been used to obtain cyclic carbonates from the reaction between epoxides and CO2, since the formation of oxazolidin-2ones, by [3+2] cycloaddition of epoxides and isocyanates was also achieved demonstrating the versatility of this type of systems.[70] Therefore, inspired by the brilliant catalytic activity showed by these hydroxy-containing mono-imidazole salts in various catalytic processes, we explored the synthesis of a second generation of catalysts 1−6 based on bis-imidazole salts (bromide and iodide) where the presence of two -OH groups in their structure significantly increases the catalytic activity. In this work, we have prepared an important substrate scope of cyclic carbonates derived from monoor disubstituted epoxides, terpenes, waste fatty acid bis-epoxide n-pentyl ester and waste vegetable oils (from cooking oils), as starting materials for the synthesis of different NIPUs materials by polyaddition reaction of carbonated vegetable oils with a variety of diamines. The obtained organocatalysts and cyclic carbonates were characterized by NMR, whereas NIPUs were characterized by NMR, IR, GPC, and their thermal properties were studied by TGA and DSC. 2. Experimental 2.1 Materials and methods All reactions involving CO2 were carried out in a stainless-steel reactor with a magnetic stirrer bar. Solvents were pre-dried over sodium wire (CH3CN, hexane and EtOAc) or CaCl2 and CHCl3 (CH2Cl2). Deuterated solvents were stored over activated 4 Å molecular sieves and degassed by several freeze-thaw cycles. 1H and 13C{1H} NMR spectra were performed on a Varian Inova FT-500 spectrometer and referenced to the residual deuterated solvent. Chemical shifts are given in parts per million (ppm) relative to TMS [1H and 13C, δ(SiMe4) = 0]. All coupling constants (J) are represented in Hz. Multiplicities are shown by brs (broad singlet), s (singlet), d (doublet), t (triplet), dd (double doublet), and m (multiplet). FTIR spectra were afforded on a Shimadzu IR Prestige-21 spectrophotometer armed with a Pike Technology ATR system. The instrument was set to acquire 32 scans per spectrum at a resolution of 4 cm−1. Elemental analysis was carried out with a Perkin-Elmer 2400 CHN analyzer. Molecular weight estimations of synthesized polymers were assessed by gel permeation chromatography (GPC, Jasco, Japan) equipped with a refractive index detector (RI-4030, Jasco) and a divinylbenzene based column (DVB column, Jordi Labs) enclosed in a column oven at 40 °C (CO-4060, Jasco). 10 mg of polymeric sample were dissolved in 1.0 mL of chloroform and stirred overnight up to the total dissolution of polymer into the solvent. Samples were measured in GPC running with chloroform as mobile phase at 1.0 mL/min. Molecular weight calculations (Mw, Mn, and polydispersity index), were done by using ChromNAV-GPC software (Jasco), using a molecular weight calibration curve made using different 4 Author name /Journal of CO2 Utilization 000 (2017) 000–000 narrow polymethylmethacrylate (PMMA) standard (ReadyCal Kit, Polymer Standard Service GmbH). Thermogravimetric analyses were done in a Perkin Elmer TGA-4000. The heating rate for the sample was 10 °C/min from 30.0°C to 500°C, and the nitrogen flow rate was 20 mL/min. Thermal characterization was done in a differential scanning calorimeter (TA Instruments DSC Q200). Around 10 mg of sample was deposited in an alumina crucible, and first applying a first cooling cycle from room temperature up to −50 ºC 10 ºC/min, followed by heating from −50 ºC up to 150 ºC at 10 ºC/min under a nitrogen atmosphere. This cycle was repeated two times. Commercially available chemicals (Sigma Aldrich) were used as received. 2.2 General procedure for the synthesis of bis-imidazolium salts 1 − 6. Bisimidazolium organocatalysts have been synthesized from neutral imidazole derived from 5-(2-hydroxyphenyl)- 1H-imidazole, which have been widely described in previous works developed by our research group [70]. A suspension of 1-dibromomethane (10 mL) and the corresponding 5-(2-hydroxyphenyl)-1-butyl-1H-imidazole derived (2.30 mmol) was heated at 95°C for 7 h, resulting in the formation of a brown precipitate. Then the following solvents CHCl3/Et2O/acetone were added to the product formed in a 1/0.2/1 ratio, which caused the precipitation of a white solid, which was filtered and dried to afford the bis-imidazolium bromide salts (1, 3 and 5). The bis-imidazolium iodide salts were obtained by the ionic exchange reaction between bis-imidazolium bromide with KI, using CH2Cl2 as solvent at rt for 30 min. Finally, a brown solid was obtained and filtered, affording bis-imidazolium iodide salts (2, 4 and 6). 1,1’-Methylenebis[4-(2-hydroxyphenyl)-3-phenyl-1H-imidazol-3-ium] dibromide (1). Obtained as pale brown solid, (1.45 g) 97% yield. An analytically pure sample was obtained by recrystallization from CHCl3. Monocrystals were grown from a CHCl3/EtOAc solution. Mp 273−274 °C. Anal. Calcd. for C31H26Br2N4O2 (646.37): C, 57.60; H, 4.05; N, 8.67. Found: C, 57.66; H, 4.10; N, 8.61. 1H NMR (500 MHz, [D6]DMSO) δ = 10.25 (s, 2H), 10.12 (m, 2H), 8.52 (m, 2H), 7.56 (d, J=4.5 Hz, 6H), 7.43 (s, 4H), 7.31 (t, J=8.0 Hz, 2H), 7.17 (d, J=7.0 Hz, 2H), 6.92−6.85 ppm (m, 6H). 13C{1H} NMR (125 MHz, [D6]DMSO) δ = 156.1, 139.2, 134.8, 132.7 132.2, 132.1, 130.7, 130.2, 130.1, 125.5, 121.7, 119.7, 116.5, 112.0 ppm. 1,1’-Methylenebis[4-(2-hydroxyphenyl)-3-phenyl-1H-imidazol-3-ium] diiodide (2). Obtained as white solid, (1.65 g) 97% yield. An analytically pure sample was obtained by recrystallization from CHCl3. Monocrystals were grown from a CHCl3/EtOAc solution. Mp 277−278 °C. Anal. Calcd. for C31H26I2N4O2 (740.37): C, 50.29; H, 3.54; N, 7.57. Found: C, 50.33; H, 3.60; N, 7.52. 1H NMR (500 MHz, [D6]DMSO) δ = 10.22 (s, 2H), 8.52 (s, 2H), 7.58 (m, 6H), 7.54 (s, 4H), 7.29 (t, J=7.5 Hz, 2H), 7.25 (d, J=7.0 Hz, 2H), 6.84−6.82 ppm (m, 6H). 13C{1H} NMR (125 MHz, [D6]DMSO) δ = 156.1, 139.1, 134.8, 132.7, 132.3, 132.2, 132.1, 130.7, 130.2, 130.1, 129.9, 125.8, 125.6, 121.7, 119.7, 116.4, 112.1 ppm. 1,1’-Methylenebis[3-butyl-4-(2-hydroxyphenyl)-1H-imidazol-3-ium] dibromide (3). Obtained as brown solid, (1.36 g) 98% yield. Mp 238−239 °C. Anal. Calcd. for C27H34Br2N4O2 (606.40): C, 53.48; H, 5.65; N, 9.24. Found: C, 53.43; H, 5.59; N, 9.27. 1H NMR (500 MHz, [D6]DMSO) δ = 10.43 (s, 2H), 9.80 (s, 2H), 8.21 (s, 2H), 7.44 (t, J=6.5 Hz, 2H), 7.29 (d, J=6.5 Hz, 2H), 7.07 (d, J=8.0 Hz, 1H), 6.99 (t, J=7.0 Hz, 2H), 6.83 (s, 2H), 4.10 (t, J=6.5 Hz, 4H), 1.671.62 (m, 4H), 1.22-1.18 (m, 4H), 0.77 ppm (t, J=7.0 Hz, 6H). 13C{1H}-NMR (125 MHz, [D6]DMSO) δ = 156.2, 138.2, 133.0, 132.8, 132.5, 121.0, 120.1, 116.6, 112.2, 58.9, 47.9, 31.1, 19.2, 13.6 ppm. 1,1’-Methylenebis[3-butyl-4-(2-hydroxyphenyl)-1H-imidazol-3-ium] diiodide (4). Obtained as brown solid, (1.51 g) 94% yield. An analytically pure sample was obtained by recrystallization from CHCl3. Monocrystals were grown from a CHCl3/EtOAc solution. Mp 207−208 °C. Anal. Calcd. for C27H34I2N4O2 (700.40): C, 46.30; H, 4.89; N, 8.00. Found: C, 46.38; H, 4.93; N, 7.92. 1H NMR (500 MHz, [D6]DMSO) δ = 10.44 (s, 2H), 9.77 (s, 2H), 8.24 (s, 2H), 7.45−7.42 (m, 2H), 7.29 (d, J=8.0 Hz, 2H), 7.07 (d, J=8.0 Hz, 2H), 6.99 (t, J=7.5 Hz, 2H), 6.81 (s, 2H), 4.11 (t, J= 7.0 Hz, 4H), 1.68−1.62 (m, 4H), 1.24−1.16 (m, 4H), 0.78 ppm (t, J=7.5 Hz, 6H). 13C{1H} NMR (125 MHz, [D6]DMSO) δ = 156.2, 138.2, 133.0, 132.9, 132.5, 120.9, 120.1, 116.6, 112.2, 58.9, 47.9, 31.1, 19.2, 13.6 ppm. Author name / Journal of CO2 Utilization 000 (2017) 000–000 5 1,1’-Methylenebis[3-butyl-4-(3,5-difluoro-2-hydroxyphenyl)-1H-imidazol-3-ium] dibromide (5). Obtained as white solid, (1.54 g) 99% yield. An analytically pure sample was obtained by recrystallization from CHCl3. Monocrystals were grown from a CHCl3/EtOAc solution. Mp 258−260 °C. Anal. Calcd. for C27H30Br2F4N4O2 (678.36): C, 47.81; H, 4.46; N, 8.26. Found: C, 47.65; H, 4.41; N, 8.29. 1H NMR (500 MHz, [D6]DMSO) δ = 10.52 (s, 2H), 10.01 (s, 2H), 8.30 (s, 2H), 7.52 (t, J=8.5 Hz, 2H), 7.21 (d, J=8.5 Hz, 2H), 6.90 (s, 2H), 4.12 (t, J=7.2 Hz, 4H), 1.67−1.62 (m, 4H), 1.24−1.18 (m, 4H), 0.79 ppm (t, J=7.3 Hz, 6H). 13C{1H} NMR (125 MHz, [D6]DMSO) δ = 154.4 (dd, J= 312.5, 15.1 Hz), 153.2 (dd, J=309.4, 16.1 Hz), 150.5 (d, J=16.4 Hz), 141.1 (d, J=19.0 Hz), 138.6, 130.1, 122.1, 115.3 (dd, J=18.9, 13.9 Hz), 114.3 (d, J=30.2 Hz), 107.9 (d, J= 29.9 Hz), 58.8, 48.1, 31.0, 19.2, 13.7 ppm. 1,1’-Methylenebis[3-butyl-4-(3,5-difluoro-2-hydroxyphenyl)-1H-imidazol-3-ium] diiodide (6). Obtained as pale brown solid, (1.49 g) 85% yield. An analytically pure sample was obtained by recrystallization from CHCl3 Monocrystals were grown from a CHCl3/EtOAc solution. Mp 259−262°C. Anal. Calcd. for C27H30F4I2N4O2 (772.37): C, 41.99; H, 3.92; N, 7.25. Found: C, 41.93; H, 3.89; N, 7.30. 1H NMR (500 MHz, [D6]DMSO) δ = 10.54 (s, 2H), 9.83 (s, 2H), 8.27 (s, 2H), 7.51 (t, J=7.0 Hz, 2H), 7.25 (d, J=5.0 Hz, 2H), 6.89 (s, 2H), 4.11 (t, J=7.0 Hz, 4H), 1.751.72 (m, 4H), 1.26−1.22 (m, 4H), 0.75 ppm (t, J=7.0 Hz, 6H). 13C{1H} NMR (125 MHz, [D6]DMSO) δ = 154.1 (dd, J= 297.5, 15.1 Hz), 152.2 (dd, J= 288.5, 16.4 Hz), 150.5 (t, J=16.3 Hz), 141.1 (t, J= 4.0 Hz), 138.6, 130.1, 122.1, 115.4-115.3 (m), 114.3 (d, J=33.8 Hz), 107.8 (t, J= 34.0 Hz), 58.9, 48.1, 31.0, 19.2, 13.7 ppm. 2.3 Synthesis of epoxidized vegetable oils Epoxidized olive oil (13) and epoxidized sunflower oil (14) were prepared following a synthetic route previously reported in the literature [19,71]. 2.4 General procedure for the optimization of reaction conditions for the preparation of cyclic carbonates 8a-c, 10, 15 and 16. Styrene oxide (7a), epichlorohydrin (7b), 1,2-epoxydodecane (7c) 8-[2-(2-pentyl-3-oxacyclopropylmethyl)-3oxacyclopropyl]octanoate (9), epoxidized olive oil (13) or epoxidized sunflower oil (14) (1.7 mmol), organocatalysts 1−6 (12.75–85.0 μmol) were located in a 30 mL stainless steel reactor with a magnetic stirrer bar. The reaction mixture was stirred at 60–100°C and 20 bar CO2 pressure for 1–44 hours, then the conversions of the epoxides into their corresponding cyclic carbonates were determined by analysis of a sample by 1H NMR spectroscopy. 2.5 General procedure for the synthesis of cyclic carbonates An epoxide (1.7 mmol) and organocatalyst 4 (12.75–85.0 μmol) were placed in a 100 mL stainless steel 4790 Parr reactor with a magnetic stirrer bar inside and connected to a high pressure CO2 line. The reaction mixture was heated at 60–100°C with a Radleys TECH stirring hot plate, pressurized a 20 bar CO2 pressure and left stirring for 1–44 hours. After the allotted time period, the reactor was cooled to ambient temperature over 1 hour and was carefully released by a gradual depressurization over the time. The transformation of epoxide to cyclic carbonate was then followed by analysis of a sample by 1H NMR spectroscopy. The remaining sample was filtered through a plug of silica, eluting with CH2Cl2 to eliminate the catalyst. The eluent was then evaporated under reduced pressure to give either the pure cyclic carbonate or a mixture of cyclic carbonate and unreacted epoxide. As later option, the mixture was purified by flash chromatography using a solvent system of first hexane, then hexane:EtOAc (9:1), then hexane:EtOAc (6:1), then hexane:EtOAc (3:1), then hexane:EtOAc (1:1), then EtOAc to give the pure cyclic carbonate. 2.6 Recyclability Study To investigate the recyclability and stability of the catalysts, the epoxidized olive oil 13 and catalyst 4 were used under the optimal reaction conditions previously determined. Epoxide 13 (1.7 mmol) and organocatalyst 4 (1.7 μmol) were placed in the reactor connected to a high pressure CO2 line. The reaction mixture was heated at 100°C, 6 Author name /Journal of CO2 Utilization 000 (2017) 000–000 pressurized at 20 bar CO2 pressure and left stirring for 9 hours. After the allotted time period, the reactor was cooled to ambient temperature over 1 hour and was carefully released by a gradual depressurization over the time. The transformation of epoxide to cyclic carbonate was then followed by analysis of a sample by 1H NMR spectroscopy. The catalyst was precipitated by adding Et2O and the reaction mixture was centrifuged to recover the catalyst 4. Subsequently, the catalyst was subjected to vacuum drying at 80 ℃ for 7 hours for the subsequent cycle experiment. The 1H-NMR spectrum of the recovered catalyst 4 showed no changes compared to freshly prepared compound. This procedure was repeated for each cycle. 2.7 General procedure for the synthesis of poly(hydroxyurethane)s 10a-d, 15a,e, 16a,b,d,e In a 10 mL vial flask equipped with a small stir bar pentyl 8-(2-oxo-5-((2-oxo-5-pentyl-1,3-dioxolan-4-yl)methyl)- 1,3-dioxolan-4-yl)octanoate (10), carbonated olive oil (15) or carbonated sunflower oil (16) (0.86 mmol), the corresponding diamine (0.86−1.72 mmol), 10 mol% of 1,8-diazabicyclo(5.4.0)undec-7-ene, DBU, (0.086 mmol) and MeCN (4 mL) were added. The reaction mixture was then heated up at 80 ºC and left stirring for 16 h. After that time, the solvent was removed under reduced pressure and the residue was washed with MeOH. The mixture was filtered, and the solvent was dried in vacuo to give the corresponding poly(hydroxyurethane). 3. Results and discussion 3.1 Synthesis and structural characterization of organocatalysts 1 − 6 A series of methylenebisimidazolium dibromides (1, 3 and 5) and diiodides (2, 4 and 6) (Fig. 1) were synthesized according to the methodology depicted in point 2.2 of the Experimental Section and were characterized by spectroscopic methods (see Supplementary data for more information). It is relevant to mention that only one set of resonances for the butyl or phenyl protons was observed in the 1H and 13C{1H} NMR spectra of compounds 1−6 at room temperature, proving that both imidazolium rings are equivalent. When compared to their dibromide analogues, the chemical shifts for the methylenebisimidazolium diiodides 2, 4, and 6 slightly differ and some signals also appear wider. In contrast to its dibromide analogue 5, the imidazole proton resonances from compound 6 are, for instance, shifted to higher field. Fig 1. Bifunctional organocatalysts 1−6. 3.2 Catalytic results for the preparation of cyclic carbonates. Once the bis-imidazole compounds 1−6 were synthesized, it was investigated their potential use as bifunctional organocatalysts for CO2 fixation into a wide diversity of cyclic carbonates. Initially, the catalytic activity of 1−6 was tested and compared with different terminal epoxides (Table 1). In general, iodide bis-imidazole derivatives 2 and 4 were more active than bromide derivatives 1 and 3, respectively, however, this trend was not observed with catalysts 5 and 6. The lower reactivity of 5 and 6 has been previously observed by our group in the cycloaddition of epoxides and isocyanates [70]. This suggests that the increase in acidity due to the presence of the fluor atoms, makes that the limiting step of the reaction is the cyclisation to obtain the cyclic carbonate, similar to what has been observed by Poater and D'Elia [58]. Thus the higher acidity of 5 and 6 would slow down the reaction rate. Amongst the catalysts under study, iodide bis-imidazole compound 4 was the most effective and it transformed an aryl, halide, and alkyl Author name / Journal of CO2 Utilization 000 (2017) 000–000 7 epoxides 7a−c into their corresponding cyclic carbonates 8a−c in outstanding conversions under the experimental reaction conditions. As can be seen in the data shown in Table 1 catalyst 4 was the most active, therefore we decided to increase the substrate scope with others monosubstituted epoxides with ether functionality 7d, and 7e where excellent catalytic results were also afforded (Fig. 2). At this point, we opted to submit catalyst 4 to further challenges by preparing a range of disubstituted cyclic carbonates 8f−h from epoxides 7f−h in good to excellent yields (Fig. 2). Cyclopentane carbonate, 8f was isolated with a high yield (98%) in the presence of 0.75 mol% of 4 in 16 h, which represents a notable improvement with respect to the catalytic result previously obtained by mono-imidazole organocatalyst [20]. It is relevant to mention that owing to the solid nature of trans-stilbene oxide 7g, the preparation of trans-1,2diphenylethylene carbonate 8g was performed at 100 ºC and a good yield was obtained. 9-Oxabicyclo[6.1.0]non-4ene epoxide 7h was also employed as substrate to give its carbonate 8h in 40% yield with a 59:41 mixture of cis/trans isomers in 16 h. As far as we know, there are only three previously reported examples for the preparation of 8h by the reaction of CO2 and epoxide 7h [72–74], and it is the first organocatalyst to achieve it, which highlights the ability of this catalyst to convert challenge epoxides into their corresponding cyclic carbonates. Table 1. Preparation of cyclic carbonates 8a–c using organocatalysts 1–6. [a] Reactions were carried out at 80 °C, 20 bar CO2 pressure for 1 h using 0.75 mol% of catalyst 1−6 under solvent free conditions. [b] Determined by 1H NMR spectroscopy. [c] Isolated yield from purified cyclic carbonate. Organocatalyst 1 2 3 4 5 6 Entry Epoxide Conv.b (%) Conv.b (%) Conv. b (%) Conv.b (%) Conv. b (%) Conv. b (%) 1 7a (R = Ph) 80 90 79 98 (96)c 54 33 2 7b (R = CH2Cl) 79 85 86 100 (98)c 80 48 3 7c (R = Oct) 7 69 18 100 (98)c 5 8 8 Author name /Journal of CO2 Utilization 000 (2017) 000–000 Fig. 2. Cyclic carbonates 8d–j obtained from their corresponding epoxides 7d–j by using organocatalyst 4. Unless otherwise stated, reactions were carried out at 80 ºC and 20 bar CO2 pressure under solvent free conditions for 1−44 h. [a] T = 100 ºC. [b] cis/trans = 59:41. Taking into consideration that catalyst 4 was able to accomplish the formation of monoand di-substituted cyclic carbonates, we explored its use as organocatalyst for the preparation of highly hindered cyclic carbonates derived from terpenes oxides. Thus, the synthesis of two tri-substituted cyclic carbonates 8i and 8j obtained from natural starting materials was carried out (Fig. 2). cis-Limonene carbonate 8i was prepared from commercially available cislimonene oxide and was isolated in 90% yield. Additionally, polycyclic carbonate 8j derived from (1R,4R,6R,10S)- 9-methylene-4,12,12-trimethyl-5-oxatricyclo[8.2.0.04,6]dodecane, caryophyllene oxide was obtained in 55% yield. It is important to highlight that the formation of a bis(cyclic carbonate) has not been observed in 8j because the appearance of a cyclic organic carbonate moiety is not favored on rings bigger than cyclooctane [72]. This cyclic carbonate was isolated diastereoselectively and a unique stereoisomer was obtained with a specific rotation value of [α]D25 = −85.3°(See Figure S38 in the Supplementary data). 3.3 Catalytic results for the preparation of a fatty acid biobased bis(cyclic carbonate) Catalysts 4 has demonstrated excellent versatility for the synthesis of a broad selection of cyclic carbonates, with this results in mind we then focused our interest to the obtention of a fatty acid biobased bis(cyclic carbonate) 10 derived from a waste fatty acid bis-epoxide n-pentyl ester 9 (cis/trans ratio of 39:61) (Table 2). The use of biobased precursors for their transformation into the corresponding cyclic carbonates is getting much consideration nowadays [19,34,38,46,54,75–77]. Firstly, the catalytic reaction was studied employing 5 mol% of organocatalyst 4 at 100 ºC and 20 bar CO2 pressure achieving a quantitative conversion of the bis(cyclic carbonate) 10 (Table 2, entry 1). Interestingly, the same results were observed when decreasing the catalytic loading to 3 mol% and the temperature to 80 ºC (Table 2, entries 2 and 3), however a slight increase to the cis orientation was detected when the temperature went down (Table 2, entry 3) (Fig. 3). Finally, lower conversions of product 10 were afforded by reducing the reaction time to 9 h and the temperature to 60 ºC, respectively (Table 2, entries 4 and 5). It is remarkable to comment that the use of an iodide ion as a nucleophile gave the trans isomer as a major product under the optimal reaction conditions as previously reported [34]. Table 2. Screening and optimization for the synthesis of bis(cyclic carbonate) 10.[a] Author name / Journal of CO2 Utilization 000 (2017) 000–000 9 Entry Cat (mol%) Temperature (ºC) Conv. [%][c] cis/trans%[d] TOF (h−1)[e] 1 4 (5) 100 100 32/68 13 2 4 (3) 100 100 38/62 21 3 4 (3) 80 100 (95)[f] 45/55 21 4[b] 4 (3) 80 46 45/55 17 5 4 (3) 60 19 80/20 4 [a]Reactions were carried out at 60–100°C and 20 bar CO2 pressure using 3−5 mol% of 4 for 24 h in the absence of a solvent. [b]time = 9 h. [c]Determined by 1H NMR spectroscopy. [d]cis/trans ratios were determined by 1H NMR spectroscopy. [f]TOF=moles of product/(moles of catalyst × time), [f]Isolated yield from purified cyclic carbonate in parenthesis. Fig 3. 1H-NMR spectrum of bis(cyclic carbonate) 10 in CDCl3 (Table 2, entry 3). To elucidate the reaction mechanism, the interactions amongst bis-imidazole organocatalyst 4 and bis-epoxide 9 with CO2 were studied spectroscopically in CDCl3 using a Young valve NMR tube (Fig. 4). Firstly, it was investigated the probable formation of hydrogen bonds between the −OH groups of the catalyst 4 and the oxygen atom of the bisepoxide 9. As can be seen in Fig. 4b, the resonance from the −OH groups of catalyst 4 at 9.40 ppm is broadened. CHcis CHcis CHtrans CHtrans a a b b 16 Author name /Journal of CO2 Utilization 000 (2017) 000–000 polymers were fully characterized by spectroscopic techniques (NMR and IR), their molecular wights and polydispersities were determined by GPC and their thermal properties were also studied by DSC and TGA. PHUs were synthesized as oligomers with low molecular weights (601−1726 g/mol) and moderate polydispersities (1.25−2.24) due to there was not a good control in the polymerization reaction and various chains with a huge variety of different molecular weights could be produced. Acknowledgements We gratefully acknowledge the financial support; grants PID2020-117788RB-I00 funded by MCIN/AEI/ 10.13039/501100011033, grant RED2022-134287-T funded by MCIN/AEI, grants SBPLY/21/180501/000132 funded by Junta de Comunidades de Castilla-La Mancha and by the EU through “Fondo Europeo de Desarollo Regional” (FEDER), and grant 2021-GRIN-31240 funded by Universidad de Castilla-La Mancha. F.W. is grateful for FONDECYT Postdoctoral fellowship 3220023. O.S.T. is grateful for FONDECYT Regular fellowship 1220241 and Concurso Ayuda de Viajes de la VID, 2022, Universidad de Chile. J.M. is grateful FONDECYT Iniciación fellowship 11230124 and FOVI230027. I. M.-V. is grateful for FONDECYT regular fellowship 1210968. Declaration of interests Authors declare no competing financial interests. Credit author statement Francisca Werlinger: Methodology, Formal Analysis, Investigation. María P. Caballero: Methodology, Formal Analysis, Investigation. Oleksandra S. Trofymchuk: Methodology, Formal Analysis, Investigation. Mario E. Flores: Methodology, Formal Analysis, Investigation. Ignacio Moreno-Villoslada: Methodology, Formal Analysis, Investigation. Felipe de la Cruz-Martínez: Investigation, Resources José A. Castro-Osma: Methodology, Formal Analysis, Investigation. Juan Tejeda: Resources, Supervision. Javier Martínez: Conceptualization, Supervision, Methodology, Validation, Investigation, Writing - Original Draft. Agustín Lara-Sánchez: Conceptualization, Supervision, Project administration, Writing-Review & Editing, Visualization, Funding acquisition. Appendix A. Supplementary data Supplementary data including experimental details, procedures for catalytic reactions, chemical structures of fatty acids found in cooking olive oil and sunflower oil, fatty acid composition of cooking olive oil, NMR for catalysts, for cyclic carbonates, for epoxides from waste vegetable oils, for cyclic carbonates from vegetable oils and for NIPUs from carbonated vegetable oils and commercial diamines. FTIR for cyclic carbonates and NIPUs materials. CPC trace from NIPUs materials and DSC and TGA analysis for NIPUs materials. Supplementary material related to this article can be found in the online version, at doi:XXXX Abbreviations BDA, 1,4-diaminobutane; CVOs, carbonated vegetable oils; DBU, 1,8-diazabicyclo(5.4.0)undec-7-ene; DFT, density functional theory; DMSO, dimethyl sulfoxide; DSC, differential scanning calorimeter; EVOs, epoxidized vegetable oils; FTIR, Fourier transform infrared spectroscopy; GC-FID, gas chromatography with flame-ionization detection; GPC, gel permeation chromatography; HBDs, hydrogen-bond donors; IR infrared spectroscopy; MOFs, metal organic frameworks; Mn, molecular weight number; NIPUs, non-isocyanate polyurethanes; NMR, nuclear magnetic resonance Author name / Journal of CO2 Utilization 000 (2017) 000–000 17 spectroscopy; PDI, polydispersity; PHUs, polyhydroxyurethanes; PMMA, polymethylmethacrylate; TBD, 1,5,7triazabicyclo[4.4.0]dec-5-ene; Td, thermal decomposition; Tg, glass temperature; TGA, thermogravimetric analyses; TMS, tetramethyl silane; WVOs, waste vegetable oils. References [1] A. Rafiee, K. Rajab Khalilpour, D. Milani, M. Panahi, Trends in CO2 conversion and utilization: A review from process systems perspective, J. Environ. Chem. Eng. 6 (2018) 5771–5794. https://doi.org/https://doi.org/10.1016/j.jece.2018.08.065. [2] National Oceanic and Atmospheric Administration (NOAA), Global monitoring laboratory—Earth system research laboratories, Trends Atmos. Carbon Dioxide, (2023). https://gml.noaa.gov/ccgg/trends/mlo.html (accessed March 30, 2023). [3] P. Anastas, N. Eghbali, Green Chemistry: Principles and Practice, Chem. Soc. Rev. 39 (2010) 301–312. https://doi.org/10.1039/B918763B. [4] M. Aresta, Carbon Dioxide as Chemical Feedstock, Wiley, 2010. https://books.google.cl/books?id=Ng5qzi52etMC. [5] M. Mikkelsen, M. Jørgensen, F.C. Krebs, The teraton challenge. A review of fixation and transformation of carbon dioxide, Energy Environ. Sci. 3 (2010) 43–81. https://doi.org/10.1039/B912904A. [6] M. Aresta, A. Dibenedetto, A. Angelini, Catalysis for the Valorization of Exhaust Carbon: from CO2 to Chemicals, Materials, and Fuels. Technological Use of CO2, Chem. Rev. 114 (2014) 1709–1742. https://doi.org/10.1021/cr4002758. [7] D.-J. Tao, F. Qu, Z.-M. Li, Y. Zhou, Promoted absorption of CO at high temperature by cuprous-based ternary deep eutectic solvents, AIChE J. 67 (2021) e17106. https://doi.org/https://doi.org/10.1002/aic.17106. [8] S. Dabral, T. Schaub, The use of carbon dioxide (CO2) as a building block in organic synthesis from an industrial perspective, Adv. Synth. Catal. 361 (2019) 223–246. https://doi.org/10.1002/adsc.201801215 [9] M.D.W. Hussain, A. Giri, A. Patra, Organic nanocages: a promising testbed for catalytic CO2 conversion, Sustain. Energy Fuels. 3 (2019) 2567–2571. https://doi.org/10.1039/C9SE00394K. [10] V. Aomchad, À. Cristòfol, F. Della Monica, B. Limburg, V. D’Elia, A.W. Kleij, Recent progress in the catalytic transformation of carbon dioxide into biosourced organic carbonates, Green Chem. 23 (2021) 1077– 1113. https://doi.org/10.1039/D0GC03824E. [11] W.J. Peppel, Preparation and Properties of the Alkylene Carbonates, Ind. Eng. Chem. 50 (1958) 767–770. https://doi.org/10.1021/ie50581a030. [12] B. Schäffner, F. Schäffner, S.P. Verevkin, A. Börner, Organic Carbonates as Solvents in Synthesis and Catalysis, Chem. Rev. 110 (2010) 4554–4581. https://doi.org/10.1021/cr900393d. [13] A. Rehman, F. Saleem, F. Javed, A. Ikhlaq, S.W. Ahmad, A. Harvey, Recent advances in the synthesis of cyclic carbonates via CO2 cycloaddition to epoxides, J. Environ. Chem. Eng. 9 (2021) 105113. https://doi.org/https://doi.org/10.1016/j.jece.2021.105113. [14] M. Martínez de Sarasa Buchaca, F. de la Cruz-Martínez, E. Francés-Poveda, J. Fernández-Baeza, L.F. Sánchez-Barba, A. Garcés, J.A. Castro-Osma, A. Lara-Sánchez, Synthesis of Nonisocyanate Poly(hydroxy)urethanes from Bis(cyclic carbonates) and Polyamines, Polymers (Basel). 14 (2022). https://doi.org/10.3390/polym14132719. [15] J. Mindemark, R. Mogensen, M.J. Smith, M.M. Silva, D. Brandell, Polycarbonates as alternative electrolyte host materials for solid-state sodium batteries, Electrochem. Commun. 77 (2017) 58–61. https://doi.org/https://doi.org/10.1016/j.elecom.2017.02.013. [16] D. Prasad, K.N. Patil, J.T. Bhanushali, B.M. Nagaraja, A.H. Jadhav, Sustainable fixation of CO2 into epoxides to form cyclic carbonates using hollow marigold CuCo2O4 spinel microspheres as a robust catalyst, Catal. Sci. Technol. 9 (2019) 4393–4412. https://doi.org/10.1039/C9CY00945K. [17] F.M. Al-Qaisi, A.K. Qaroush, I.K. Okashah, A.F. Eftaiha, P. Vasko, F. Alsoubani, T. Repo, The Use of Sustainable Transition Metals for the Cycloaddition of Epoxides and CO2 under Mild Reaction Conditions, Eur. J. Inorg. Chem. 26 (2023) e202200357. https://doi.org/https://doi.org/10.1002/ejic.202200357. [18] D. Prasad, K.N. Patil, N.K. Chaudhari, H. Kim, B.M. Nagaraja, A.H. Jadhav, Paving way for sustainable earth-abundant metal based catalysts for chemical fixation of CO2 into epoxides for cyclic carbonate formation, Catal. Rev. 64 (2022) 356–443. https://doi.org/10.1080/01614940.2020.1812212. 18 Author name /Journal of CO2 Utilization 000 (2017) 000–000 [19] J. Martínez, F. de la Cruz-Martínez, M.M. de Sarasa Buchaca, M.P. Caballero, R.M. Ojeda-Amador, M.D. Salvador, G. Fregapane, J. Tejeda, J.A. Castro-Osma, A. Lara-Sánchez, Valorization of agricultural waste and CO2 into bioderived cyclic carbonates, J. Environ. Chem. Eng. 9 (2021) 105464. https://doi.org/10.1016/j.jece.2021.105464. [20] J.A. Castro-Osma, J. Martínez, F. de la Cruz-Martínez, M.P. Caballero, J. Fernández-Baeza, J. RodríguezLópez, A. Otero, A. Lara-Sánchez, J. Tejeda, Development of hydroxy-containing imidazole organocatalysts for CO2 fixation into cyclic carbonates, Catal. Sci. Technol. 8 (2018) 1981–1987. https://doi.org/10.1039/C8CY00381E. [21] L. Guo, K.J. Lamb, M. North, Recent developments in organocatalysed transformations of epoxides and carbon dioxide into cyclic carbonates, Green Chem. 23 (2021) 77–118. https://doi.org/10.1039/D0GC03465G. [22] D.-H. Lan, N. Fan, Y. Wang, X. Gao, P. Zhang, L. Chen, C.-T. Au, S.-F. Yin, Recent advances in metal-free catalysts for the synthesis of cyclic carbonates from CO2 and epoxides, Chinese J. Catal. 37 (2016) 826–845. https://doi.org/https://doi.org/10.1016/S1872-2067(15)61085-3. [23] S. Ravi, J. Kim, Y. Choi, H.H. Han, S. Wu, R. Xiao, Y.-S. Bae, Metal-Free Amine-Anchored Triazine-Based Covalent Organic Polymers for Selective CO2 Adsorption and Conversion to Cyclic Carbonates Under Mild Conditions, ACS Sustain. Chem. Eng. 11 (2023) 1190–1199. https://doi.org/10.1021/acssuschemeng.2c06621. [24] C. Claver, M. Bin Yeamin, M. Reguero, A.M. Masdeu-Bultó, Recent advances in the use of catalysts based on natural products for the conversion of CO2 into cyclic carbonates, Green Chem. 22 (2020) 7665–7706. https://doi.org/10.1039/D0GC01870H. [25] A. Valverde-González, M.C. Borrallo-Aniceto, U. Díaz, E.M. Maya, F. Gándara, F. Sánchez, M. Iglesias, Nitrogen-rich cobalt (II) MOFs as efficient bifunctional catalysts for single or tandem oxidation and CO2 conversion reactions, J. CO2 Util. 67 (2023) 102298. https://doi.org/https://doi.org/10.1016/j.jcou.2022.102298. [26] P. Ma, M. Ding, Y. Zhang, W. Rong, J. Yao, Integration of lanthanide-imidazole containing polymer with metal-organic frameworks for efficient cycloaddition of CO2 with epoxides, Sep. Purif. Technol. 313 (2023) 123498. https://doi.org/https://doi.org/10.1016/j.seppur.2023.123498. [27] F. Liu, X. Duan, X. Dai, S. Du, J. Ma, F. Liu, M. Liu, Metal-decorated porous organic frameworks with crosslinked pyridyl and triazinyl as efficient platforms for CO2 activation and conversion under mild conditions, Chem. Eng. J. 445 (2022) 136687. https://doi.org/https://doi.org/10.1016/j.cej.2022.136687. [28] Z. Gao, L. Liang, X. Zhang, P. Xu, J. Sun, Facile One-Pot Synthesis of Zn/Mg-MOF-74 with Unsaturated Coordination Metal Centers for Efficient CO2 Adsorption and Conversion to Cyclic Carbonates, ACS Appl. Mater. Interfaces. 13 (2021) 61334–61345. https://doi.org/10.1021/acsami.1c20878. [29] T.K. Pal, D. De, P.K. Bharadwaj, Metal–organic frameworks for the chemical fixation of CO2 into cyclic carbonates, Coord. Chem. Rev. 408 (2020) 213173. https://doi.org/https://doi.org/10.1016/j.ccr.2019.213173. [30] F. Norouzi, A. Abdolmaleki, CO2 conversion into carbonate using pyridinium-based ionic liquids under mild conditions, Fuel. 334 (2023) 126641. https://doi.org/https://doi.org/10.1016/j.fuel.2022.126641. [31] R.B. Mujmule, H. Kim, Efficient imidazolium ionic liquid as a tri-functional robust catalyst for chemical fixation of CO2 into cyclic carbonates, J. Environ. Manage. 314 (2022) 115045. https://doi.org/https://doi.org/10.1016/j.jenvman.2022.115045. [32] Q. Li, W. Dai, J. Mao, X. He, Y. Liu, Y. Xu, L. Yang, J. Zou, X. Luo, Facile integration of hydroxyl ionic liquid into Cr-MIL-101 as multifunctional heterogeneous catalyst for promoting the efficiency of CO2 conversion, Microporous Mesoporous Mater. 350 (2023) 112461. https://doi.org/https://doi.org/10.1016/j.micromeso.2023.112461. [33] G. Fiorani, M. Stuck, C. Martín, M.M. Belmonte, E. Martin, E.C. Escudero-Adán, A.W. Kleij, Catalytic Coupling of Carbon Dioxide with Terpene Scaffolds: Access to Challenging Bio-Based Organic Carbonates., ChemSusChem. 9 (2016) 1304–1311. https://doi.org/10.1002/cssc.201600238. [34] J. Martínez, F. de la Cruz-Martínez, M. Martínez de Sarasa Buchaca, J. Fernández-Baeza, L.F. Sánchez-Barba, M. North, J.A. Castro-Osma, A. Lara-Sánchez, Efficient Synthesis of Cyclic Carbonates from Unsaturated Acids and Carbon Dioxide and their Application in the Synthesis of Biobased Polyurethanes, Chempluschem. 86 (2021) 460–468. https://doi.org/10.1002/cplu.202100079. [35] J. Fernández-Baeza, L.F. Sánchez-Barba, A. Lara-Sánchez, S. Sobrino, J. Martínez-Ferrer, A. Garcés, M. Author name / Journal of CO2 Utilization 000 (2017) 000–000 19 Navarro, A.M. Rodríguez, NNC-Scorpionate Zirconium-Based Bicomponent Systems for the Efficient CO2 Fixation into a Variety of Cyclic Carbonates, Inorg. Chem. 59 (2020) 12422–12430. https://doi.org/10.1021/acs.inorgchem.0c01532. [36] L. Longwitz, J. Steinbauer, A. Spannenberg, T. Werner, Calcium-Based Catalytic System for the Synthesis of Bio-Derived Cyclic Carbonates under Mild Conditions, ACS Catal. 8 (2018) 665–672. https://doi.org/10.1021/acscatal.7b03367. [37] H. Blattmann, M. Fleischer, M. Bähr, R. Mülhaupt, Isocyanateand phosgene-free routes to polyfunctional cyclic carbonates and green polyurethanes by fixation of carbon dioxide, Macromol. Rapid Commun. 35 (2014) 1238–1254. https://doi.org/10.1002/marc.201400209. [38] A. Brandolese, F. Della Monica, M. Pericàs, A.W. Kleij, Catalytic Ring-Opening Copolymerization of Fatty Acid Epoxides: Access to Functional Biopolyesters, Macromolecules. 55 (2022) 2566–2573. https://doi.org/10.1021/acs.macromol.2c00321. [39] C.-M. Lam, I.K.M. Yu, S.-C. Hsu, D.C.W. Tsang, Life-cycle assessment on food waste valorisation to valueadded products, J. Clean. Prod. 199 (2018) 840–848. https://doi.org/https://doi.org/10.1016/j.jclepro.2018.07.199. [40] A. Orjuela, J. Clark, Green chemicals from used cooking oils: Trends, challenges, and opportunities., Curr. Opin. Green Sustain. Chem. 26 (2020) 100369. https://doi.org/10.1016/j.cogsc.2020.100369. [41] B. Saba, A.K. Bharathidasan, T.C. Ezeji, K. Cornish, Characterization and potential valorization of industrial food processing wastes, Sci. Total Environ. 868 (2023). https://doi.org/10.1016/j.scitotenv.2023.161550. [42] H. Deviren, H. Aydın, Production and physicochemical properties of safflower seed oil extracted using different methods and its conversion to biodiesel, Fuel. 343 (2023). https://doi.org/10.1016/j.fuel.2023.128001. [43] E. Gómez-Trejo-López, M.O. González-Díaz, M. Aguilar-Vega, Waste cooking oil transesterification by sulfonated polyphenylsulfone catalytic membrane: Characterization and biodiesel production yield, Renew. Energy. 182 (2022) 1219–1227. https://doi.org/10.1016/j.renene.2021.11.003. [44] S. Félix, J. Araújo, A.M. Pires, A.C. Sousa, Soap production: A green prospective, Waste Manag. 66 (2017) 190–195. https://doi.org/10.1016/j.wasman.2017.04.036. [45] J. Catalá, M.P. Caballero, F. De La Cruz-Martínez, J. Tejeda, J.A. Castro-Osma, A. Lara-Sánchez, J.M. García-Vargas, M.T. García, M.J. Ramos, I. Gracia, J.F. Rodríguez, Carbonation of epoxidized soybean oil in supercritical CO2 assisted by imidazole-based organocatalysts, J. CO2 Util. 61 (2022). https://doi.org/10.1016/j.jcou.2022.102060. [46] (a) A. Centeno-Pedrazo, J. Perez-Arce, Z. Freixa, P. Ortiz, E.J. Garcia-Suarez, Catalytic Systems for the Effective Fixation of CO2 into Epoxidized Vegetable Oils and Derivates to Obtain Biobased Cyclic Carbonates as Precursors for Greener Polymers, Ind. Eng. Chem. Res. 62 (2023) 3428–3443. https://doi.org/10.1021/acs.iecr.2c03747; (b) F. Chen, Q. C. Zhang, D. Wei, Q. Bu, B. Dai, N. Liu, Highly Stereo-Controlled Synthesis of Fatty Acid-Derived Cyclic Carbonates by Using Iron(II) Complex and Nucleophilic Halide, J. Org. Chem. 84 (2019) 11407−11416. https://doi.org/10.1021/acs.joc.9b01068; (c) L. Peña Carrodeguas, À. Cristòfol, J. M. Fraile, J. A. Mayoral, V. Dorado, C. I. Herrerías, A. W. Kleij, Fatty acid based biocarbonates: Al-mediated stereoselective preparation of mono-, diand tricarbonates under mild and solvent-less conditions, Green Chem., 19 (2017) 3535–3541. https://doi.org/10.1039/C7GC01206C. [47] C. Mokhtari, F. Malek, A. Manseri, S. Caillol, C. Negrell, Reactive jojoba and castor oils-based cyclic carbonates for biobased polyhydroxyurethanes, Eur. Polym. J. 113 (2019) 18–28. https://doi.org/10.1016/j.eurpolymj.2019.01.039. [48] M. Kurańska, H. Beneš, A. Prociak, O. Trhlíková, Z. Walterová, W. Stochlińska, Investigation of epoxidation of used cooking oils with homogeneous and heterogeneous catalysts, J. Clean. Prod. 236 (2019) 117615. https://doi.org/https://doi.org/10.1016/j.jclepro.2019.117615. [49] M.A.C. Mhd. Haniffa, K. Munawar, Y.C. Ching, H.A. Illias, C.H. Chuah, Bio-based Poly(hydroxy urethane)s: Synthesis and Pre/Post-Functionalization, Chem. - An Asian J. 16 (2021) 1281–1297. https://doi.org/10.1002/asia.202100226. [50] M. Włoch, K. Błazek, Isocyanate-Free Polyurethanes, in: ACS Symp. Ser., 2021: pp. 107–166. https://doi.org/10.1021/bk-2021-1380.ch005. [51] J. Dong, B. Liu, H. Ding, J. Shi, N. Liu, B. Dai, I. Kim, Bio-based healable non-isocyanate polyurethanes driven by the cooperation of disulfide and hydrogen bonds, Polym. Chem. 11 (2020) 7524–7532. 20 Author name /Journal of CO2 Utilization 000 (2017) 000–000 https://doi.org/10.1039/d0py01249a. [52] B. Bizet, E. Grau, H. Cramail, J.M. Asua, Volatile Organic Compound-Free Synthesis of Waterborne Poly(hydroxy urethane)-(Meth)acrylic Hybrids by Miniemulsion Polymerization, ACS Appl. Polym. Mater. 2 (2020) 4016–4025. https://doi.org/10.1021/acsapm.0c00657. [53] M. Ghasemlou, F. Daver, E.P. Ivanova, B. Adhikari, Bio-based routes to synthesize cyclic carbonates and polyamines precursors of non-isocyanate polyurethanes: A review, Eur. Polym. J. 118 (2019) 668–684. https://doi.org/10.1016/j.eurpolymj.2019.06.032. [54] C. Carré, Y. Ecochard, S. Caillol, L. Avérous, From the Synthesis of Biobased Cyclic Carbonate to Polyhydroxyurethanes: A Promising Route towards Renewable Non-Isocyanate Polyurethanes, ChemSusChem. 12 (2019) 3410–3430. https://doi.org/10.1002/cssc.201900737. [55] S. Doley, S.K. Dolui, Solvent and catalyst-free synthesis of sunflower oil based polyurethane through nonisocyanate route and its coatings properties, Eur. Polym. J. 102 (2018) 161–168. https://doi.org/10.1016/j.eurpolymj.2018.03.030. [56] L. Poussard, J. Mariage, B. Grignard, C. Detrembleur, C. Jéroîme, C. Calberg, B. Heinrichs, J. De Winter, P. Gerbaux, J.-M. Raquez, L. Bonnaud, P. Dubois, Non-Isocyanate Polyurethanes from Carbonated Soybean Oil Using Monomeric or Oligomeric Diamines to Achieve Thermosets or Thermoplastics, Macromolecules. 49 (2016) 2162–2171. https://doi.org/10.1021/acs.macromol.5b02467. [57] B. Tamami, S. Sohn, G.L. Wilkes, Incorporation of Carbon Dioxide into Soybean Oil and Subsequent Preparation and Studies of Nonisocyanate Polyurethane Networks, J. Appl. Polym. Sci. 92 (2004) 883–891. https://doi.org/10.1002/app.20049. [58] P. Yingcharoen, C. Kongtes, S. Arayachukiat, K. Suvarnapunya, S.V.C. Vummaleti, S. Wannakao, L. Cavallo, A. Poater, V. D’ Elia, Assessing the pKa-Dependent Activity of Hydroxyl Hydrogen Bond Donors in the Organocatalyzed Cycloaddition of Carbon Dioxide to Epoxides: Experimental and Theoretical Study, Adv. Synth. Catal. 361 (2019) 366–373. https://doi.org/https://doi.org/10.1002/adsc.201801093. [59] H. Tong, Y. Qu, Z. Li, J. He, X. Zou, Y. Zhou, T. Duan, B. Liu, J. Sun, K. Guo, Halide-free pyridinium saccharinate binary organocatalyst for the cycloaddition of CO2 into epoxides, Chem. Eng. J. 444 (2022) 135478. https://doi.org/https://doi.org/10.1016/j.cej.2022.135478. [60] W. de A. Bezerra, J.L.S. Milani, C.H. de J. Franco, F.T. Martins, Â. de Fátima, Á.F.A. da Mata, R.P. das Chagas, Bis-benzimidazolium salts as bifunctional organocatalysts for the cycloaddition of CO2 with epoxides, Mol. Catal. 530 (2022) 112632. https://doi.org/https://doi.org/10.1016/j.mcat.2022.112632. [61] L. Gao, Y. Zhou, Z. Li, J. He, Y. Qu, X. Zou, B. Liu, C. Ma, J. Sun, K. Guo, Nicotinamide onium halide bidentate hybrid H–bond donor organocatalyst for CO2 fixation, J. CO2 Util. 65 (2022) 102196. https://doi.org/https://doi.org/10.1016/j.jcou.2022.102196. [62] F. Zhang, S. Bulut, X. Shen, M. Dong, Y. Wang, X. Cheng, H. Liu, B. Han, Halogen-free fixation of carbon dioxide into cyclic carbonates via bifunctional organocatalysts, Green Chem. 23 (2021) 1147–1153. https://doi.org/10.1039/D0GC03846F. [63] Y. Hu, Z. Wei, A. Frey, C. Kubis, C.-Y. Ren, A. Spannenberg, H. Jiao, T. Werner, Catalytic, Kinetic, and Mechanistic Insights into the Fixation of CO2 with Epoxides Catalyzed by Phenol-Functionalized Phosphonium Salts, ChemSusChem. 14 (2021) 363–372. https://doi.org/https://doi.org/10.1002/cssc.202002267. [64] N. Liu, Y.-F. Xie, C. Wang, S.-J. Li, D. Wei, M. Li, B. Dai, Cooperative Multifunctional Organocatalysts for Ambient Conversion of Carbon Dioxide into Cyclic Carbonates, ACS Catal. 8 (2018) 9945–9957. https://doi.org/10.1021/acscatal.8b01925. [65] Y. Hao, D. Yuan, Y. Yao, Metal-Free Cycloaddition of Epoxides and Carbon Dioxide Catalyzed by TriazoleBridged Bisphenol, ChemCatChem. 12 (2020) 4346–4351. https://doi.org/https://doi.org/10.1002/cctc.202000508. [66] Á. Mesías-Salazar, J. Martínez, R.S. Rojas, F. Carrillo-Hermosilla, A. Ramos, R. Fernández-Galán, A. Antiñolo, Aromatic guanidines as highly active binary catalytic systems for the fixation of CO2 into cyclic carbonates under mild conditions, Catal. Sci. Technol. 9 (2019) 3879–3886. https://doi.org/10.1039/C9CY00667B. [67] H. Büttner, L. Longwitz, J. Steinbauer, C. Wulf, T. Werner, Recent Developments in the Synthesis of Cyclic Carbonates from Epoxides and CO2, Top. Curr. Chem. 375 (2017) 50. https://doi.org/10.1007/s41061-0170136-5. Author name / Journal of CO2 Utilization 000 (2017) 000–000 21 [68] F.D. Bobbink, D. Vasilyev, M. Hulla, S. Chamam, F. Menoud, G. Laurenczy, S. Katsyuba, P.J. Dyson, Intricacies of Cation–Anion Combinations in Imidazolium Salt-Catalyzed Cycloaddition of CO2 Into Epoxides, ACS Catal. 8 (2018) 2589–2594. https://doi.org/10.1021/acscatal.7b04389. [69] M.H. Anthofer, M.E. Wilhelm, M. Cokoja, M. Drees, W.A. Herrmann, F.E. Kühn, Hydroxy-Functionalized Imidazolium Bromides as Catalysts for the Cycloaddition of CO2 and Epoxides to Cyclic Carbonates, ChemCatChem. 7 (2015) 94–98. https://doi.org/https://doi.org/10.1002/cctc.201402754. [70] M.P. Caballero, F. Carrascosa, F. de la Cruz-Martínez, J.A. Castro-Osma, A.M. Rodríguez, M. North, A. LaraSánchez, J. Tejeda, [4-(2-Hydroxyphenyl)imidazolium Salts as Organocatalysts for Cycloaddition of Isocyanates and Epoxides to Yield Oxazolidin-2-ones, ChemistrySelect. 7 (2022) e202103977. https://doi.org/https://doi.org/10.1002/slct.202103977. [71] F. Werlinger, R. Caprile, V. Cárdenas-Toledo, B. Tarraff, Á. Mesías-Salazar, R.S. Rojas, J. Martínez, O.S. Trofymchuk, M.E. Flores, Approach to Circular Chemistry Preparing New Polyesters from Olive Oil, ACS Omega. 8 (2023) 21540−21548. https://doi.org/10.1021/acsomega.3c00623. [72] V. Laserna, G. Fiorani, C.J. Whiteoak, E. Martin, E. Escudero-Adán, A.W. Kleij, Carbon Dioxide as a Protecting Group: Highly Efficient and Selective Catalytic Access to Cyclic cis-Diol Scaffolds, Angew. Chemie Int. Ed. 53 (2014) 10416–10419. https://doi.org/https://doi.org/10.1002/anie.201406645. [73] C. Miceli, J. Rintjema, E. Martin, E.C. Escudero-Adán, C. Zonta, G. Licini, A.W. Kleij, Vanadium(V) Catalysts with High Activity for the Coupling of Epoxides and CO2: Characterization of a Putative Catalytic Intermediate, ACS Catal. 7 (2017) 2367–2373. https://doi.org/10.1021/acscatal.7b00109. [74] J. Martínez, J. Fernández-Baeza, L.F. Sánchez-Barba, J.A. Castro-Osma, A. Lara-Sánchez, A. Otero, An Efficient and Versatile Lanthanum Heteroscorpionate Catalyst for Carbon Dioxide Fixation into Cyclic Carbonates, ChemSusChem. 10 (2017) 2886–2890. https://doi.org/https://doi.org/10.1002/cssc.201700898. [75] H. Büttner, C. Grimmer, J. Steinbauer, T. Werner, Iron-Based Binary Catalytic System for the Valorization of CO2 into Biobased Cyclic Carbonates, ACS Sustain. Chem. Eng. 4 (2016) 4805–4814. https://doi.org/10.1021/acssuschemeng.6b01092. [76] S. Hu, X. Chen, J.M. Torkelson, Biobased Reprocessable Polyhydroxyurethane Networks: Full Recovery of Crosslink Density with Three Concurrent Dynamic Chemistries, ACS Sustain. Chem. Eng. 7 (2019) 10025– 10034. https://doi.org/10.1021/acssuschemeng.9b01239. [77] B. Nohra, L. Candy, J.-F. Blanco, C. Guerin, Y. Raoul, Z. Mouloungui, From petrochemical polyurethanes to biobased polyhydroxyurethanes, Macromolecules. 46 (2013) 3771–3792. https://doi.org/10.1021/ma400197c. [78] N.D. Harrold, Y. Li, M.H. Chisholm, Studies of Ring-Opening Reactions of Styrene Oxide by Chromium Tetraphenylporphyrin Initiators. Mechanistic and Stereochemical Considerations, Macromolecules. 46 (2013) 692–698. https://doi.org/10.1021/ma302492p. [79] R.H. Lambeth, T.J. Henderson, Organocatalytic synthesis of (poly)hydroxyurethanes from cyclic carbonates and amines, Polymer (Guildf). 54 (2013) 5568–5573. https://doi.org/https://doi.org/10.1016/j.polymer.2013.08.053. [80] A. Bossion, R.H. Aguirresarobe, L. Irusta, D. Taton, H. Cramail, E. Grau, D. Mecerreyes, C. Su, G. Liu, A.J. Müller, H. Sardon, Unexpected Synthesis of Segmented Poly(hydroxyurea–urethane)s from Dicyclic Carbonates and Diamines by Organocatalysis, Macromolecules. 51 (2018) 5556–5566. https://doi.org/10.1021/acs.macromol.8b00731. [81] S. Benyahya, J.-P. Habas, R. Auvergne, V. Lapinte, S. Caillol, Structure–property relationships in polyhydroxyurethanes produced from terephthaloyl dicyclocarbonate with various polyamines, Polym. Int. 61 (2012) 1666–1674. https://doi.org/https://doi.org/10.1002/pi.4257. [82] S. Benyahya, B. Boutevin, S. Caillol, V. Lapinte, J.-P. Habas, Optimization of the synthesis of polyhydroxyurethanes using dynamic rheometry, Polym. Int. 61 (2012) 918–925. https://doi.org/https://doi.org/10.1002/pi.4159.