High Intensity Ultrasound Assisted Transesterification of Espresso Coffee Oil Methyl Ester: Optimization through Response Surface Methodology Approach

Abstract

High intensity ultrasound was used to accelerate the ester conversion of biodiesel production from espresso coffee oil (ECO) with a base-catalyzed transesterification. The ester conversion from ECO biodiesel production was optimized through three parameters: methanol, potassium hydroxide, and ultrasonic reaction time with a response surface methodology (RSM). After ECO has gone through the ultrasonic homogenizer (1000W ultrasonic power, 18 kHz ultrasonic frequency) for the biodiesel production. The maximum methyl ester of 96.385 wt.% was achieved under an optimal condition: 30.8 vol.% methanol, 16.6 gKOH/L, and 72 sec ultrasonic reaction time.