Chemical interesterification of cotton oil with methyl acetate assisted by ultrasound for biodiesel production

Abstract

In this study, research was performed on the interesterification reaction of cotton oil with methyl acetate, using potassium methoxide as catalyst, in the presence of ultrasonic waves. In order to obtain a better understanding of the process variables behavior, a response surface methodology was used along with statistical methods. The experiments were performed with molar ratio varying from 1:8 to 1:24, catalyst percentage of 0.1 to 1.3% (weight), ultrasonic nozzle amplitude varying from 30% to 90% (180 to 540 W) and vibration pulse varying from 50% to 90%. Process variables were optimized with the optimal molar ratio of 1:14.87, catalyst concentration of 1.17%, ultrasonic probe amplitude of 67.64% and vibration pulse of 67.30%. The average conversion of triglycerides was found to be 98.12% at the optimal conditions. The experimental data were adjusted to the second-order irreversible reaction approximation model, under optimized conditions, with temperatures of 30, 40 and 50 ºC. Lastly, in comparison to the conventional methodology, a significant increase of 14% of triglycerides conversion utilizing ultrasonic waves was observed.