Alkali-catalyzed transesterification of waste cooking oil with cosolvent

Abstract

To study the effect factors of biodiesel synthesis from waste cooking oil (WCO) used in food frying using transesterification reaction. The series of experiment were carried out by using potassium hydroxide with 2.6, 2.9 and 3.1 wt% potassium hydroxide to WCO between 10, 15 and 30 minutes and WCO to methanol molar ratio 1:9. In addition, the thesis also investigated cosolvent of biodiesel synthesis in order to accelerate the reaction rate by improving the miscibility of methanol and WCO by the cosolvent. Tetrahydrofuran (THF), Methyl Tertiary Butyl Ether (MTBE) and diethyl ether (DEE) was used as a cosolvent due to they are miscible in both methanol and WCO, cheap price, non-toxic, inert to the reaction and easy to remove from the product due to their boiling point are close to methanol. The experiments were carried out by using methanol to cosolvent 1:0.2 by mole. The experiment result showed that potassium hydroxide 2.6 wt% is suitable for the reaction. From the experiments at 400 rpm found that the maximum methyl ester contents obtained from the reaction at 60 degree Celsius, 30 minutes were 92.8% for the reaction without cosolvent. While methyl ester contents from the reaction with THF, MTBE and DEE cosolvent at the same condition are 95.8%, 93.8% and 94.0% respectively.