Production of methyl ester from palm fatty acid and palm stearin using sulfuric acid and potassium hydroxide as catalysts

Abstract

In this study, esterification and transesterification of palm fatty acid and palm stearin with methanol using sulfuric acid and potassium hydroxide as catalysts was investigated. The reaction was carried out in batch reactor at atmospheric pressure and temperature of 60 degree celsius. The amount of catatyst used 0.5% and 1.0% by weight of oil. Excess methanol of 2 and 4 times than stoichiometric ratio were used. The reaction time was 1 hour for every experiment. The reaction was using palm fatty acid, palm stearin and mixed various concentrations of palm fatty acid in palm stearin 0, 25, 50, 75 and 100%. The results show that the optimum conditions when using potassium hydroxide and sulfuric acid as catalyst for transesterification and esterification were catalyst of 1% by weight of oil and excess methanol of 4 times the stoichiometric ratio and the reaction time of 1 hour were investigated. Methyl ester concentration of 94.44 and 55.73 wt% was obtained at this condition. The results showed that the concentration of methyl ester production from the reaction of palm stearin with potassium hydroxide was higher compared to that with sulfuric acid catalyst. Since sulfuric acid is relatively fast for converting the free fatty acid to methyl ester. From experiment can see when increasing amount of catalyst from 0.5% to 1% by weight of oil and increasing excess methanol from 2 to 4 times the stoichiometric ratio result in the increased concentration of methyl esters production.