Improvement of lubricity of sulfonated methyl ester from vegetable oil soapstocks

Abstract

The purpose of this study was to synthesis sulfonated methyl ester with lubricating property from palm oil and rice bran oil soapstocks. Firstly, soapstocks were changed to methyl esters by esterification using methanol and concentrated sulfuric acid as a catalyst. Then methyl ester products were reacted with oleum to produce sulfonated methyl esters. The sulfonated methyl esters were identified by spectroscopic techniques, such as infrared spectroscopy, nuclear magnetic resonance spectroscopy, and x-ray fluorescence spectrometer. The resulting sulfonated methyl esters could be easily blended with base diesel fuel and used as lubricity improver. At 5% by weight, both sulfonated methyl esters gave the same value of mean wear scar diameter of 192 um, as the standard value of mean wear scar diameter was less than 460 um. Therefore, these products could improve the lubricity performance of base diesel fuel.