Biofuel Synthesis from Waste Cooking Oils and Ethyl Acetate via Interesterification under CaO Catalyst from Waste Eggshells

A conventional biofuel production via transesterification of fatty acids and alcohols in presence of a basic or acidic catalyst produces glycerol by-product that lowers the biofuel yield. Alternatively, interesterification reaction has been gained further attention to substitute the conventional reaction due to no glycerol formation. Furthermore, the interesterification produces a value-added by-product of triacetin, a good bio-additive as anti-knocking agent and cetane number improver. The aim of this work is to investigate the interesterification of fatty acids in waste cooking oil (WCO) and ethyl acetate (ETA) under solid catalyst calcium oxide (CaO) catalyst derived from eggshells for biofuel production. The eggshell catalyst not only reduces environmental problem, but also reduces the cost of biofuel raw material. In this study, eggshell waste was grounded after cleaning up and the powder produced was calcined at 900˚C for 4 hours in a furnace. The catalyst was characterized using the Fourier transform-infrared spectroscopy and the biofuel yield was determined by the gas chromatography. A certain amount of 4.0 wt% of catalyst was consumed throughout the experiment with varied parameters such as molar ratio of WCO and ETA, reaction time and temperature. The subsequent results indicate that the CaO derived from eggshell can convert the fatty acids in WCO to biofuel with high quality according to ASTM specifications.