Submitted to: Book Chapter
Publication Type: Book / chapter
Publication Acceptance Date: 3/20/2003
Publication Date: 3/20/2003
Citation: HWANG, H., ERHAN, S.Z. LUBRICANT BASE STOCKS FROM MODIFIED SOYBEAN OIL. Erhan, S.Z., Perez, J.M., editors. AOCS Press, Champaign, IL. 2002. p. 20-34. Interpretive Summary:
Technical Abstract: "Lubricant Base Stocks from Modified Soybean Oil" discusses a variety of potential lubricant base fluids prepared by chemical modification of epoxidized soybean oil. The opening of the epoxy-ring structure allows for the addition of substituents to enhance low-temperature properties and improve the oxidation stability of base fluids. The substituents added include cyclic hydrocarbons and straight- and branched- chain hydrocarbons. Epoxidized soybean oil has been transformed to ring-opened products by reaction with various alcohols in the presence of sulfuric acid as a catalyst. Considerable amounts of transesterification products are observed during the ring-opening reaction with the exceptions of the reaction with 2,2-dimethyl-1-propanol and a controlled reaction with Jarcol I-18T. Fully-transesterified products incorporating 2-ethyl-1-hexanol and Jarcol I-18T have pour points of -12 and -30 deg C, respectively. The effect of pour point depressants (PPD) was studied. The addition of 1% PPD further lowered the pour point to -21 deg C for the product from 2-ethyl-1-hexanol and -36 deg C for the product from Jarcol I-18T. Acid anhydride was then used to esterify the hydroxy groups in the aforementioned ring-opened product. The resulting products contain the functional groups of -CH(OR^1)CH(OCOR^2)- in place of the epoxy group. Structural effect of substituents, R^1 and R^2 on pour points of the product has been systematically investigated in the presence and absence of 1% PPD. The pour points of the esterified products range from 6 to -42 deg C and from 0 to -48 deg C without and with 1% PPD, respectively, depending on the R^1 and R^2 substituents. A modified Penn State micro-oxidation test of three selected products shows these lubricant candidates to have similar or better oxidative stability relative to synthetic lubricant base fluids such as polyalphaolefin (PAO) and some esters (adipates).