Fatty acid methyl ester production by transesterification of refined palm oil with methanol catalysed by anion-exchange resin with tetrahydrofuran as a co-solvent

Abstract

Alkaline anion exchange resins, specifically dense AmberLiteTM IRA402 and porous AmberLystTM A26, are used to study the transesterification of palm oil and methanol. A common industrial process for creating biodiesel or green solvents is transesterification. While homogeneous catalysts like sodium methoxide and sodium hydroxide are used in most transesterification facilities, heterogeneous catalysts have the benefit of being simpler to separate from the finished product. The goal of this study was to better understand how palm oil and methanol combine to produce fatty acid methyl ester (FAME), a prevalent kind of biodiesel. Previous studies mainly investigated the production of fatty acid ethyl ester (FAEE) by trans esterifying palm oil with ethanol. However, the goal of this research was to examine the utilization of alkaline anion exchange resins for the transesterification of palm oil and methanol with addition of THF as co-solvent. Transesterification from IRA402, which is a dense catalyst, suggested that rate of FAME production is linearly dependent of concentration of oil. While the methanol does not affect the FAME content much. By varying the basic sites of resin, the yield also gets affected which means external mass transfer is ruled out for controlling reaction. The rate determining step for IRA402 is most likely the reaction of acylglycerol and methoxide at the surface of resin. In case of A26, the reaction was controlled by external mass transfer as yield did not get affected by changing the basic sites at the surface. But the reaction fell after some time due to the formation of secondary phase that eventually blocks the pores of resins. The secondary phase is triggered by presence of glycerol which was confirmed when glycerol was added at the start of transesterification reaction. Reaction rate modelling has been done for both resins. The reaction rate constants obtained through data fitting.