Esterification of Palm Fatty Acid Distillate for FAME Synthesis Catalyzed by Super-Acid Catalyst HClSO3–ZrO2

Abstract

The current work investigates biodiesel synthesis from the cheaper source- palm fatty acid distillate (PFAD) using HClSO3–ZrO2 acid catalyst. The effect of various physicochemical parameters such as molar ratio, catalyst loading, temperature, molecular sieves addition, and agitation speed was studied. The maximum conversion of 91.5% and yield of 90.2% was achieved in 150 min under the reaction conditions of molar ratio 8:1, amount of catalyst 3.5 wt%, 60 °C, agitation speed 250 rpm, and molecular sieves 5 wt%. While comparing the catalytic activity with Amberlyst-15 in converting PFAD to FAME, it was found that HClSO3–ZrO2 gave 7.2 times more conversion as compared to Ambetlyst-15 for similar reaction conditions. Catalyst reusability was also tested and showed a negligible decrease in the conversion at least for three cycles. The kinetics and thermodynamics properties were investigated with the help of Arrhenius equation and Eyring reaction rate theory. The physicochemical properties of the purified PFAD biodiesel were compared with the petroleum diesel and also matched with American Society for Testing and Materials (ASTM) standards and found within the limit.