Investigation on synthesis of trimethylolpropane (TMP) ester from non-edible oil

Abstract

Trimethylolpropane (TMP) ester is an eco-friendly lubricant that fully biodegradable and known as bio lubricant. In this study, TMP ester was produced from waste cooking oil and rubber seed oil through a two-step synthesis approach. The reaction is two stages transesterifications, in which the waste cook-ing oil and the rubber seed oil were first transesterified with methanol to produce methyl ester, fol-lowed by transesterification with TMP using para-Toluenesulfonic acid (p-TSA) as catalyst. Various ef-fects of operating conditions were observed, such as reaction time, temperature and molar ratio of reac-tants. The TMP ester formation was determined based on the quantity of reactant conversion. The syn-thesized TMP ester was compared and characterized according to their properties. The results showed that the TMP ester from waste cooking oil (WCO) has shown better conversion compare to TMP ester from rubber seed oil (RSO), within a similar operating condition. The highest TMP ester conversion from WCO is 71%, at temperature of 150 °C with molar ratio of FAME to TMP of 3:1 and catalyst amount of 2% (wt/wt). In addition, these polyol based esters from WCO and RSO exhibit appropriate basic properties for viscosity when compare with requirement standard of lubricant ISO VG46.