Esterification of Free Fatty Acid on Palm Fatty Acid Distillate using Activated Carbon Catalysts Generated from Coconut Shell

Abstract

In the last few years, biodiesel has emerged as one of the most potential renewable energy to replace current petrol-derived diesel. It is a renewable, biodegradable and non-toxic fuel which can be easily produced through esterification of triglycerides (vegetable oils or animal fats) or esterification of free fatty acids (FFAs) with methanol. However, current commercial usage of refined vegetable oils for biodiesel production is impractical and uneconomical due to high feedstock cost and priority as food resources. Low-grade oil, can be a better alternative; however, the high free fatty acids (FFA) content has become the main drawback for this potential feedstock. Solid acid catalysts offer significant advantages of eliminating separation, corrosion, toxicity and environmental problems. Recently, a new strategy of preparing novel carbon-based solid acids has been developed. In this research, the esterification reactions of Palm Fatty Acid Disttillate (PFAD) with methanol, using carbon based solid catalyst from coconut shell activated carbon as catalyst, were studied. The ester preparation involved an esterification reaction, followed by purification. In this study, the activated carbon catalyst catalysts were synthesized by sulfonating the activated carbon using concentrated H2SO4. The physico-characteristics and acid site densities were analyzed by Nitrogen gas adsorption, FT-IR, X-ray fluorescent (XRF), and acid-base back titration methods. The effects of the molar ratio of methanol to oil (6:1 to 12:1), the amount of catalyst (1-10%), and the reaction temperature (40, 50 and 60oC) were studied for the conversion of FFA to optimize the reaction conditions. The optimal conditions were an methanol/PFAD molar ratio of 12:1, the amount of catalyst of 10%wt., and reaction temperature of 60oC.