Activity of Calcium Methoxide Catalyst for Synthesis of High Oleic Palm Oil Based Trimethylolpropane Triesters as Lubricant Base Stock

Abstract

High oleic palm oil based trimethylolpropane triesters (TMPTE) are potential biodegradable base stocks for lubricant production. Calcium methoxide was used as a catalyst for the synthesis of TMPTE through chemical transesterification of high oleic palm oil methyl esters (POME) with trimethylolpropane (TMP). The effects of the main operating variables, i.e., temperature, pressure, molar ratio of TMP to POME, and the catalyst amount, on the yield of TMPTE were appraised. The amount of soap produced under these conditions was examined. The optimum conditions for the reaction were the reaction temperature set at 170 °C, molar ratio of TMP:POME set at 1:6, pressure of the system maintained at 50 mbar, and mass ratio of calcium methoxide set at 0.3% per weight of reaction mixture. Trimethylolpropane esters containing 98% w/w triesters were successfully synthesized under these conditions within 8 h reaction time. Saponification occurred under these conditions; however, the soap formation was less than that produced when homogeneous catalyst was used.