Esterification Free Fatty Acid in Palm Fatty Acid Distillate using Sulfonated Rice Husk Ash Catalyst

Indonesia, as one of the biggest palm oil producers and exporters in the world, is producing large amounts of low-grade oil such as Palm Fatty Acid Distillate (PFAD) from palm oil industries. The use of PFAD can reduce the cost of biodiesel production significantly, which makes PFAD a highly potential alternative feedstock for biodiesel production. In this paper, the esterification of free fatty acid (FFA) on PFAD was studied using rice husk ash (RHA) as heterogeneous catalyst. The rice husk ash catalyst was synthesized by sulfonation using concentrated sulfuric acid. The RHA catalyst were characterized by using different techniques, such as porosity analysis, Fourier transform infrared (FTIR) spectroscopy, total number of acid sites and elemental analysis. The effects of the molar ratio of methanol to PFAD (1-10%), the molar ratio of methanol to PFAD (4: 1-10: 1), and the reaction temperature (40-60 degrees C) were studied for the conversion of FFA to optimize the reaction conditions. The results showed that the optimal conditions were an methanol to PFAD molar ratio of 10: 1, the catalyst amount of 10 wt% of PFAD, and reaction temperature of 60 degrees C.