Abstract
To produce soybean oil-based lubricants with good oxidative stability and low pour point, epoxidized soybean oil (SBO) was chemically modified. Epoxidized SBO was reacted with various alcohols in the presence of sulfuric acid as a catalyst to give a ring-opened intermediate product. In this step, the epoxy group was transformed to the functional group of-CH(OR1)CH(OH)-(where the R1=methyl, 1-butyl, 2-butyl, 1-hexyl, cyclohexyl, 2,2-dimethyl-1-propyl, or 1-decyl). The 1H nuclear magnetic resonance spectra of the products indicated that transesterification was accompanied by the ringopening reaction except when the bulky 2,2-dimethyl-1-propanol was used. Acid anhydride was used to esterify the hydroxy groups in the ring-opened product. This resulted in a fluid that is a lubricant candidate with the functional group of −CH(OR1)CH(OCOR2)−. Pour point studies of the resulting products showed that the pour points varied with the substituents, R1 and R2. Products with R1=CH3(CH2)5− and R2=CH3(CH2)2−, (CH3)2CH−, or CH3(CH2)4-showed the lowest pour points (−39, −39, and −45°C, respectively) when 1% of pour point depressant was added. For the oxidative stability test, two products, in which R1, R2=CH3(CH2)5−, (CH3)2CH− and R1, R2=CH3(CH2)5−, CH3(CH2)4−, were chosen for a modified Penn State micro-oxidation test. In the oxidative stability test, the products gave 69–71% of oxidative evaporation and 10–17% of tetrahydrofuran-insoluble deposits in 3 h at 175°C. The amounts of deposits were much lower than those of soybean oil (96%) and epoxidized SBO (83%) and even less than those of most petroleum-based lubricant basestocks (3–93%).
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
References
Asadauskas, S., J.M. Perez, and J.L. Duda, Oxidative Stability and Antiwear Properties of High Oleic Vegetable Oils, Lubr. Eng. 52:877–882 (1996).
Asadauskas, S., J.M. Perez, and J.L. Duda, Lubrication Properties of Castor Oil-Potential Basestock for Biodegradable Lubricants, ——Ibid. 53:35–40 (1997).
Erhan, S.Z., and S. Asadauskas, Lubricant Basestocks from Vegetable Oils, Ind. Crops Prod. 11:277–282 (2000).
Frankel, E.N., Free Radical Oxidation, in Lipid Oxidation, edited by E.N. Frankel, The Oily Press, Dundee, Scotland, 1999, pp. 23–78.
Porter, N.A., L.S. Lehman, B.A. Weber, and K.J. Smith, Unified Mechanism for Polyunsaturated Fatty Acid Autooxidation. Competition of Peroxy Radical Hydrogen Atom Abstraction, β-Scission, and Cyclization, J. Am. Chem. Soc. 103:6447–6455 (1981).
Becker, R., and A. Knorr, An Evaluation of Antioxidants for Vegetable Oils at Elevated Temperatures, Lubr. Sci. 8:95–117 (1996).
Rhee, I.S., C. Velez, and K. Bernewitz, Evaluation of Environmentally Acceptable Hydraulic Fluids, TARDE Tech. Report 13640, U.S. Army Tank-Automotive Command Research, Development and Engineering Center, Warren, MI, 1995, pp. 1–15.
Asadauskas, S., and S.Z. Erhan, Depression of Pour Points of Vegetable Oils by Blending with Diluents Used for Biodegradable Lubricants, J. Am. Oil Chem. Soc. 76:313–316 (1999).
de Jong, S., T.C. van Soest, and M.A. van Schaick, Crystal Structures and Melting Points of Unsaturated Triacylglycerols in the β Phase, ——Ibid. 68:371–378 (1991).
D'Souza, V., L. deMan, and J.M. deMan, Polymorphic Behavior of High-Melting Glycerides from Hydrogenated Canola Oil, ——Ibid. 68:907–911 (1991).
Javni, I., and Z. Petrovic, Polymers from Soybean Oil, Annu. Tech. Conf.-Soc. Plast. Eng. 55th 1:791–795 (1997).
Thames, S.F., and H. Yu, Cationic UV-Cured Coatings of Epoxide-Containing Vegetable Oils, Surf. Coat. Technol. 115:2–3 (1999).
Crivello, J.V., R. Narayan, and S.S. Sternstein, Photoinitiated Cationic Polymerization of Naturally Occurring Epoxidized Triglycerides, J. Appl. Polym. Sci. 64:2073–2087 (1997).
Gast, L.E., C.B. Croston, W.J. Schneider, and H.M. Teeter, Synthetic Lubricants from Polyhydroxystearic Acids, Ind. Eng. Chem. 46:2205–2208 (1954).
Perez, J.M., F.A. Kelley, E.E. Klaus, and V. Bagrodia, Development and Use of the PSU Micro Oxidation Test for Diesel Engine Oils, Society of Automotive Engineers, Technical Paper Series, Paper No. 872028, SAE, Warrendale, PA, 1987.
Lee, C.J., E.E. Klaus, and J.L. Duda, Evaluation of Deposit Forming Tendency of Mineral and Synthetic Base Oils Using the Penn State Micro-oxidation Test, Lubr. Eng. 49:441–445 (1993).
Standard Test Method for Pour Point of Petroleum Products D 97, ASTM Standards, American Society for Testing Materials, Philadephia, 1991, Vol. 05.02, pp. 57–64.
Palekar, V., J.L. Duda, and E.E. Klaus, Evaluation of High-Temperature Liquid Lubricants Using the Penn State Micro-oxidation Test, Lubr. Eng. 52:327–334 (1995).
Author information
Authors and Affiliations
Corresponding author
About this article
Cite this article
Hwang, HS., Erhan, S.Z. Modification of epoxidized soybean oil for lubricant formulations with improved oxidative stability and low pour point. J Amer Oil Chem Soc 78, 1179–1184 (2001). https://doi.org/10.1007/s11745-001-0410-0
Received:
Accepted:
Issue Date:
DOI: https://doi.org/10.1007/s11745-001-0410-0