Methyl Ester Production from Rubber Seed oil Using Two-Step Pretreatment Process

Abstract

Vegetable oil methyl ester is a very suitable substitute to diesel fuel as green energy or renewable energy in CI engines. A method has been developed to form methyl ester from rubber seed oil, by reducing the acid value of the oil having about 24% free fatty acids (FFAs) to 2 mg KOH/g by a two-stage pretreatment process. The first stage requires about 0.4 v/v of methanol–oil ratio and the second stage 0.35 v/v of methanol, in the presence of an acid catalyst, 1% v/v H2SO4, with continuous stirring at a temperature of 63(±2)°C. The mixture is provided one hour settling time to form the top layer as methanol–water mixture, which is removed. The bottom layer is subjected to transesterification with 0.3 v/v of methanol–oil ratio in the presence of 0.5 w/v KOH as alkaline catalyst to produce rubber seed oil methyl ester. The properties of rubber seed oil methyl ester are comparable with diesel fuel as per the ASTM D6751.