Production of methyl ester from palm stearin and fatty acid by two step method

Abstract

To investigate the production of methyl ester by two step method. Palm stearin and fatty acids were used as raw materials and were mixed at a ratio of 10%, 15% and 25% of free fatty acids. The experiments were carried out in a batch reactor using sulfuric acid as a catalyst in the first step and potassium hydroxide in the second step. The experiments were conducted at the temperature of 60°C and at atmosphere’s pressure. Reaction time, methanol to oil ratio and amount of catalysts were varied in each experiment. The suitable conditions on acid esterification process were 300% mole of excess methanol from its stoichiometric ratio in the presence of 2% wt H2SO4 as a catalyst and at the reaction time of 70 minutes. High free fatty acids level was reduced to less than 2% in the first step. Acid catalyst can simultaneously catalyze both esterification of free fatty acids and transesterification of triglyceride. The suitable conditions on transesterification process were 100% mole of excess methanol from its stoichiometric ratio in the presence of 1% wt KOH as a catalyst in the second step. Final methyl ester was higher than 85% concentration within 60 minutes.