Ferric Sulphate Catalyzed Esterification of High Free Fatty Acids Content Waste Coconut Oil for Biodiesel Synthesis

Feedstock with high free fatty acids (FFAs) content can be successfully employed for biodiesel synthesis once the high FFA content is reduced to the desired levels. In the present study, the applicability of ferric sulphate as the solid acid catalyst for esterification of FFA in waste coconut oil was evaluated at varying catalyst dosage and methanol: oil molar ratios.1.25, 2.5, 3.75 and 5.0 % w/w Fe2 (SO4) 3 on oil basis was used at methanol: oil ratios of 3.81: 1, 5.72: 1 and 7.63: 1 and at the reaction temperature of 60 0C. The FFA reduced more with the increase in catalyst and methanol: oil molar ratios while the time requirement to reach the esterification equilibrium reduced. Final FFA level of 2.00 % w/w on oil can be achieved by esterification at a reaction period of 36.94 minutes in the presence of 3.75 % w/w of Fe2 (SO4) 3 catalyst dosage at 7.63: 1 methanol: oil molara ratio and 60 0C reaction temperature, which then can be subjected for trans-esterification process. At the end of the considering reaction period the solid Fe2 (SO4) 3 catalyst could be separated from the reaction system.