PRODUCTION AND ASSESSMENT OF JATROPHA CURCAS OIL BASED BIOLUBRICANT FOR LIGHT GEAR APPLICATIONS

International Journal of Advanced Scientific and Technical Research ISSN 2249-9954 Available online on http://www.rspublication.com/ijst/index.html volume 15, No. 5, 2025 DOI: 10.5281/zenodo.17330429 Original Article ©2025 RS Publication, [email protected] 153 PRODUCTION AND ASSESSMENT OF JATROPHA CURCAS OIL BASED BIOLUBRICANT FOR LIGHT GEAR APPLICATIONS Emmanuel Okon Wilson and Kokoette Idiong Etim Department of Mechanical Engineering, Akwa Ibom State Polytechnic, Ikot Osurua, Akwa Ibom, Nigeria PMB 1200 Corresponding E-mail addresses: ✉ [email protected] ARTICLE INFO ABSTRACT Paper ID: IJASTR68DD600ECDE23 Paper ID: IJASTR68DC0B9A3E3C4 Received: 2025-09-02 Published: 2025-1002 DOI: https://dx.doi.o rg/10.5281/zenod o.17330429 Page No: 153-163 The jatropha curcas oil was extracted from the seed with the use of a soxhlet apparatus with petroleum ether as the solvent for oil extraction. The extracted oil was subjected to physiochemical characterisation to determine the its density, acid value, free fatty acid value (FFA) content, kinematic viscosity at 50˚C and 100˚C , its viscosity index and saponification value. A value of 15.2% was determined for the FFA which is above the threshold value for oils to be used as lubricant thus indicating that virgin Jatropha curcas seed oil is unsuitable for use as lubricant in its raw form. Thus the raw, unaltered jatropha curcas oil was pre-treated via esterification using methanol and this reduced the FFA content to 0.51%. This pre-treated oil with lower FFA was then subjected to a two stage transesterification process. The first stage saw the oil transformed into its methyl esters (FAME) and the second stage transforming the methyl ester through polyol transesterification with ethylene glycol resulting in the synthesis of the biolubricant. The synthesised biolubricant was assessed for conformance with current industrial standard lubricant and its tribological and thermal properties were in line. The biolubricant had pour point, kinematic viscosity at 50 ˚C and 100˚C, and viscosity index determined to be -8˚C, 59.25cSt, 11.52cSt and 191.15 respectively. These values showed that the formulated biolubricant exhibits favourable properties even at low temperature, stable viscositytemperature behaviour, and perfect lubricative properties. These performance parameters were found to be in tandem with ISO VG-46 commercial lubricants which are utilised in light and industrial gear applications. Keywords: Jatropha curcas, biolubricant, two stage transesterification, tribological and thermal properties, oil extraction, physiochemical characterisation 1. INTRODUCTION The demand for petroleum-based lubricants has put a strain on the world reserve of crude oil. It has also been discovered that there are negative environmental consequences associated with International Journal of Advanced Scientific and Technical Research Available online on http://www.rspublication.com/ijst/index.html ISSN 2249-9954 Cite This Paper : Emmanuel Okon Wilson and Kokoette Idiong Etim (2025). "PRODUCTION AND ASSESSMENT OF JATROPHA CURCAS OIL BASED BIOLUBRICANT FOR LIGHT GEAR APPLICATIONS". INTERNATIONAL JOURNAL OF ADVANCED SCIENTIFIC AND TECHNICAL RESEARCH (IJASTR), vol. 15, no. 5, 2025, pp. 152-161. DOI: https://dx.doi.org/10.5281/zenodo.17330429 International Journal of Advanced Scientific and Technical Research ISSN 2249-9954 Available online on http://www.rspublication.com/ijst/index.html volume 15, No. 5, 2025 DOI: 10.5281/zenodo.17330429 Original Article ©2025 RS Publication, [email protected] 154 the use of petroleum-based lubricants (Adolf et al., 2018), (Udounwa and Wilson, 2025). These reasons and more have necessitated the need for a deviation from the use of petroleum-based products to the use of more environmentally friendly alternatives. The use of “green” lubricants has been envisaged. This is due to the fact that they are readily available and most importantly, they are biodegradable, thus rendering them environmentally friendly (Wilson et al., 2024). A drawback to the use of green alternatives is that it puts a strain on the availability of food for human consumption. To this end, it has been suggested that only parts of plants which are not edible be used as bio-lubricants (Karmakar et al., 2017). This has assisted in freeing up large volumes of agricultural products for human usage and consumption. This also serves as a means of recycling agricultural waste. Jatropha curcas seed is known for its possession of high oil yield and due to its inedible nature, it serves as an excellent alternative for use as biolubricant (Li and Wang, 2015). On its own, raw Jatropha curcas seed oil has poor oxidative stability, high pour point, and an inadequate viscosity index, and these factors render it unsuitable for use as lubricant. To remedy this disadvantage, the raw Jatropha curcas oil must be subjected to chemical modifications such as transesterification, epoxidation, and polyesterification, which would transform it and render it suitable for use as bio-lubricant. This research looks at the synthesis of bio-lubricant from Jatropha curcas seed oil and assessing its suitability for use in industries by comparing it side-by-side with ASTM standard performing lubricants (Musa et al., 2016). 2. MATERIALS AND METHODS 2.1 Materials and reagents The materials used for this study include Jatropha curcas seed, analytical grade reagents used include petroleum ether, potassium hydroxide (KOH), sodium hydroxide (NaOH), hydrochloric acid (HCl), sulfuric acid (H 2 SO 4 ), isopropyl alcohol, sodium methoxide solution, and phenolphthalein indicator. All chemicals were procured in high quality to minimize experimental variability. 2.2 Instruments and equipment The following instruments were used, a mechanical press for pulverizing the seeds to reduce diameter and increase the surface area for the extraction solvent to penetrate, a soxhlet apparatus for extraction of oil from pulverized seeds, a viscometer for measuring the resulting oils viscosity. Other equipment include a heating mantle, water bathe, an analytical weighing balance, laboratory glassware including graduated cylinders, conical flasks, burettes, pipettes, beakers, round bottom flasks were procured and employed. Magnetic stirrers, retort stands with clamps, Liebig condensers with ground glass joints, thermometers were used in measuring room and elevated temperatures. 2.3 Methodological approach The methodology for this study was achieved in the following phases. i. Preliminary preparation of Jatropha curcas seed parts prior to oil extraction. ii. Extraction of oil from pulverized and dried Jatropha curcas seed. iii. Physiochemical characterization of extracted Jatropha curcas oil. International Journal of Advanced Scientific and Technical Research ISSN 2249-9954 Available online on http://www.rspublication.com/ijst/index.html volume 15, No. 5, 2025 DOI: 10.5281/zenodo.17330429 Original Article ©2025 RS Publication, [email protected] 155 iv. Chemical modification of extracted Jatropha curcas oil via esterification and transesterification to produce the biolubricant. v. Testing and comparison of produced biolubricant with ASTM standard lubricants. 2.3.1 Preliminary Preparation of Jatropha curcas Seed before extraction (Oil seed pretreatment) The following processed where undertaken when preparing the specimens prior to extraction. These processes included: a) Washing of Seed Parts Here, the avocado seed parts were washed in water to remove debris. This was done so as to avoid contamination of the oil during extraction. b) Pulverisation of seed The seeds were grated, that is, reduced in size to allow for increased surface area so the solvent to be used can percolate and get to every area and part of the substrates. As shown in Figures 1a-b is a pictorial representation of the grating process. Fig 1a and 1b: Pulverisation of Jatropha seeds to increase the surface area prior to oil extraction c) Drying of Pulverised Jatropha Seed to remove moisture The Pulverised Seeds (see Figure 2) were spread under the sun for four (4) days to achieve perfect dryness. They were dried to remove all forms of moisture prior to extraction. The figure below shows the avocado parts while being dried. Fig. 2: Pulverised grated Jatropha seeds International Journal of Advanced Scientific and Technical Research ISSN 2249-9954 Available online on http://www.rspublication.com/ijst/index.html volume 15, No. 5, 2025 DOI: 10.5281/zenodo.17330429 Original Article ©2025 RS Publication, [email protected] 156 2.3.2 Extraction of oil from pulverized and dried Jatropha curcas seed. As shown in Figure 3, the oil extraction was carried out at the pharmacognosy postgraduate laboratory, University of Uyo, Uyo, Akwa Ibom State. The solvent extraction method was selected due to its efficiency in terms of oil yield. Since oil is a non-polar material, a non-polar solvent was selected to be used for the extraction. Petroleum Ether was used in extracting oils from the specimens. The Soxhlet extraction method was used in a bid to minimize solvent loss and maximise its use. 2000g of dried in batches of 500g, crushed and dried Jatropha seeds were put into the extraction chamber. Petroleum Ether was put into the boiling flask. And the set up was clamped onto the heating mantel. The heating mantel was switched on and temperature was maintained at 10 ˚C. As the heating mantel temperature increased, the Petroleum Ether evaporated from temperature increase. Upon evaporation, it flowed into the condenser section where water supply cooled it off and it dropped into the extraction chamber. When the condensed petroleum ether filled the extraction chamber, it was siphoned back into the boiling flask together with the extracted oil from the extraction chamber. This process was repeated for four (4) hours. After that, the equipment was switched off and the crushed seed from which oil was extracted into the solvent was removed and replaced with another 1000g of dried, crushed substrate. After extracting oil from 2000g of crushed and dried jatropha seeds, the oil which is fussed with Petroleum Ether inside the boiling flask was poured into a container and kept in the open within room temperature for the petroleum ether to be evaporated thereby remaining only pure avocado seed. Fig 3 (a) Weighing the dried, pulverised Jatropha curcas seeds (b) Petroleum Ether (c) Heating Mantel (d) Soxhlet apparatus set-up. International Journal of Advanced Scientific and Technical Research ISSN 2249-9954 Available online on http://www.rspublication.com/ijst/index.html volume 15, No. 5, 2025 DOI: 10.5281/zenodo.17330429 Original Article ©2025 RS Publication, [email protected] 157 2.3.3 CHARACTERIZATION OF JATROPHA CRUDE OIL Density Analytical weighing balance was used to weigh an empty beaker, after which its mass was recorded. 40 cm³ of the substrate, which is the Jatropha curcas oil was put in the empty beaker, and the new mass was weighed. The net mass of the substrate, which is the Jatropha curcas oil, was derived by subtracting the combined mass from the mass of the empty beaker. The density of the oil was derived from the ratio of the sample mass to the known volume, which is 40 cm³ as presented in Equation 1.  =     (1) Viscosity The kinematic viscosity for the Jatropha curcas oil sample was derived at 50°C and 100°C, respectively, using a viscometer. A beaker containing the oil was put inside the heating mantle and the temperature was increased, while constantly stirring the oil to achieve uniform heating. The spindle mounted onto the viscometer was immersed in the oil to the calibration mark, which was situated at the middle of the shaft indentation. The spindle rotated up until steady state conditions were achieved, which was shown by the dial reading. The dynamic viscosity of the sample was identified at the final reading and expressed in millipascal-seconds (mPa), in conformance with ASTM D445 guidelines for viscosity measurement. Saponification value The saponification value (SV) was determined in line with AOCS guidelines. 2.00g of Jatropha curcas oil was weighed and infused into a conical flask. 50 cm³ of 0.5 N ethanolic KOH was added to the flask and the mixture gently stirred, which resulted in total saponification of the triglycerides. The unreacted KOH was titrated against 0.5 N hydrochloric acid using 3 drops of phenolphthalein indicator (Mohammed-Dabo et al., 2012). The saponification value of the oil samples was then calculated using Equation 2.   = ( ! )(#!$ % #&')(().+)   (2) Pour point The oil was transferred into a test tube suspended in a laboratory refrigerator and cooled until complete solidification was achieved. The solid test tube was removed and allowed to defrost under ambient temperature, after which a thermometer was used to identify the temperature at which the test tube first began to turn molten. This temperature was recorded as the pour point of the oil. This temperature was seen as the lowest temperature at which the oil exhibited the ability to flow under gravity. This was also indicative of the oil's lowest operational temperature Percentage free fatty acid (%FFA) International Journal of Advanced Scientific and Technical Research ISSN 2249-9954 Available online on http://www.rspublication.com/ijst/index.html volume 15, No. 5, 2025 DOI: 10.5281/zenodo.17330429 Original Article ©2025 RS Publication, [email protected] 158 To determine the percentage-free fatty acid in a method in line with the American Oil Chemists’ Society (AOCS) Official Method Cd 5a-40, 2.00g of Jatropha curcas oil was put in a conical flask and its mass was recorded. 20 ml of isopropyl alcohol and 3 drops of phenolphthalein indicator solution was added. The mixture was titrated with 0.1 N potassium hydroxide solution while being stirred. Stirring continued until a pink end point showed for 30 seconds. The free fatty acid content was derived using Equation 3. %-- = (. % !/)(#!$ % #&')(01.0)   2 100 (3) Acid value To determine the acid value of the oil in line with the American Oil Chemists’ Society (AOCS) Official Method Cd 5a-40, 1.00g of Jatropha curcas oil was put in a conical flask, and 25 milliliters of isopropyl alcohol was added alongside 3 drops of phenolphthalein indicator, 0.1N sodium hydroxide was added and the mixture stirred until a pink precipitate was noticed. The acid value was determined using Equation 4. 56  = ( ! )(#!$ % #&')(().+)   2 100 (4) Oil esterification Esterification of the oil was necessary to reduce the pre-fatty acid content of the oil. To do this, 100 grams of Jatropha curcas oil was put into a 2L round-bottom flask. Methanol and concentrated sulfuric acid of 5% (w/w) and 20% (w/w) respectively were put into a conical flask and poured into the round-bottom flask containing 100 grams of oil. The new mixture was precipitated in a thermostatic water base at 50˚C. The reaction was maintained at 50˚C under continuous stirring at 500 revolutions per minute (rpm). After an hour (60 minutes), the sample was removed using a pipette and titrated with 0.1N KOH solution. This was done to determine the residual pre-fatty acid content. 2.3.4 Transesterification of the oil This process converts the triglycerides into fatty acid acyl esters, FAAE, using low molecular weight alcohols such as methanol (Demirbas, 2011). The synthesis of the biolubricant pertaining to this research was achieved through a two-stage transesterification process. This two-stage transesterification process involved: (i) The conversion of the extracted oil to methyl esters. (ii) Transforming the methyl esters into a polyester through another transesterification reaction involving polyol. This two-stage transesterification process was chosen as it will result in the synthesis of lubricants with favorable tribological properties, biodegradability, and lubricity. (i) Methyl ester synthesis International Journal of Advanced Scientific and Technical Research ISSN 2249-9954 Available online on http://www.rspublication.com/ijst/index.html volume 15, No. 5, 2025 DOI: 10.5281/zenodo.17330429 Original Article ©2025 RS Publication, [email protected] 159 The first stage of transesterification was done using methanol in the presence of potassium hydroxide. 100 milliliters of Jatropha curcas oil was reacted with methanol in the ratio 3 to 1 at temperature of 60 degrees centigrade while continuously being steered for a period of 20 minutes. (ii) Biolubricant synthesis The second transesterification stage involved the conversion of the methyl ester to biolubricant by reacting it with ethylene glycol in the ratio of 3.5:1. This reaction was carried out in 50 mL batches. 0.5 M sodium methoxide of 0.8% was used and it was prepared by dissolving freshly caught metallic sodium in 20% methanol as the catalyst. The entire reaction lasted for three hours and the mixture was heated to a temperature of 120˚C. The process is demonstrated in Figures 4-6. Fig 4a Fig 4b Fig 4c Fig 4 (a) Jatropha curcas oil in a reactor inside water bath (b) preheating of the water bath (c) Jatropha curcas oil esterification products in separation funnels International Journal of Advanced Scientific and Technical Research ISSN 2249-9954 Available online on http://www.rspublication.com/ijst/index.html volume 15, No. 5, 2025 DOI: 10.5281/zenodo.17330429 Original Article ©2025 RS Publication, [email protected] 160 Fig 5a Fig 5b Fig 5c Fig 5(a) Separation of synthesised Jatropha curcas oil biolubricant from by-products (b) Cleaning of biolubricant (c) Completely cleaned and separated Jatropha curcas oil biolubricant and water Fig 6: Synthesised Jatropha curcas biolubricant in test tubes ready for testing in mechanical industrial applications 3. RESULTS AND DISCUSSION The results obtained from the experimental analysis of both the freshly extracted, unaltered Jatropha curcas oil and the formulated biolubricant are displayed in Tables 1, 2, and 3. The findings are discussed under three major sub-sections: (i) physicochemical characterization of the crude Jatropha oil, (ii) reduction of free fatty acid (FFA) content through esterification, and (iii) evaluation of the physicochemical and lubricating properties of the synthesized Jatrophabased biolubricant. International Journal of Advanced Scientific and Technical Research ISSN 2249-9954 Available online on http://www.rspublication.com/ijst/index.html volume 15, No. 5, 2025 DOI: 10.5281/zenodo.17330429 Original Article ©2025 RS Publication, [email protected] 161 3.1 Characterization of Jatropha curcas raw, virgin and unaltered oil The important characteristics of the crude Jatropha curcas oil with reference to lubricity include kinematic viscosities at 50 °C and 100 °C, viscosity index, and pour point. As displayed in Table 1, these characteristics were analysed to be 71.24 cSt, 15.15 cSt, 215.9, and 5 °C, respectively. The combination of relatively high viscosity, excellent viscosity index, and a good pour point are indicative that raw, virgin Jatropha curcas oil possesses favourable physicochemical characteristics, making it a suitable and reliable raw material for biolubricant productions. The esterification result showing the decrease in FFA with time is presented in Table 2. Furthermore, the properties of synthesized biolubricant are shown in Table 3. Table 1: Characteristics of Jatropha curcas Oil S/N Property Units Values 1 Density Kg/m 910.7 2 Acid value Mg KOH/g 31.07 3 Free fatty acid(FFA) % 13.9 4 Saponification value - 189.94 5 Pour point °C 4.7 6 Viscosity@40°C cSt 71.24 7 Viscosity@100°C cSt 15.15 8 Viscosity index (vi) - 215.9 Table 2: The esterification result showing the decrease in FFA with time. S/N Time (h) FFA (%) 1 0 15.2 2 1 13.25 3 2 6.98 4 3 4.32 5 4 2.15 6 5 0.51 Table 3. Properties of synthesized biolubricant alongside standard properties according to ISO VG-46 and those of petroleum based lubricant (Abdullahi ,2012) Property Jatropha crude oil Jatropha biolubricant ISO VG-46 Petroleum based lubricant* Density @ 25°C (Kg/m) 3 910.7 902.8 - 885.6 Viscosity@40°C (cSt) 71.24 59.25 >41.4 10.801 Viscosity@100°C (cSt) 15.15 11.52 >4.1 3.136 Viscosity index 215.9 191.15 >90 165.4 Pour point 5 - 8 - 10 - 9 The free fatty acid (FFA) content of the raw, virgin Jatropha curcas oil was analysed to be 15.2%, which is quite high. At this high value, the direct use of the extracted raw Jatropha curcas oil for lubricant synthesis would likely result in very high saponification values, leading to undesirable consequences such as foam formation. Also, in alkaline-catalyzed