Comparative study of low-grade crude coconut oil esterification over SO4/ZrO2and SO4/TiO2catalysts

The esterification reaction of low-grade coconut oil to reduce free fatty acid (FFA) has been performed using SO4/ZrO2 (SZ) and SO4/TiO2 (ST) catalysts. SZ and ST catalysts were synthesized using the wet impregnation method and characterized by FTIR before and after the acidity test, then applied to the esterification step. The esterification process was carried out with variations in the weight of SZ and ST catalysts (1%, 3%, 5%, and 7%) from the total weight of oil and methanol and variations in reaction times (30, 60, 90, 120, 150, and 180 minutes). FTIR and GCMS characterized the esterified oil. The optimum conditions of the esterification process were obtained at 5% weight of SZ and ST catalysts, a reaction time of 150 minutes, and a temperature of 55 °C for SZ and ST catalysts. The SZ catalyst obtained a reduction percentage in FFA content of 65.80%, while the ST catalyst was 72.05%.