The optimization of tetrahydrofuran as a co-solvent on biodiesel production from rubber seeds using response surface methodology

The present work aims to investigate the impact of tetrahydrofuran as a co-solvent on biodiesel production from rubber seeds to accelerate the transesterification reaction with a high biodiesel yield. We extracted the oil from rubber seeds before being reacted with methanol to synthesize biodiesel. It reveals that the composition of rubber seed oil was palmitic acid of 9.71 %, stearic acid of 13.09 %, oleic acid of 19.23 %, linoleic acid of 37.49 %, and linolenic acid of 20.47 %. The esterification process was examined to diminish the FFA content from 5.00 % to 1.99 %. The transesterification process was then examined to convert the triglycerides of rubber seed oil into biodiesel. The process variables in the transesterification were defined by Box Behnken Design, and the optimum condition was evaluated by response surface methodology. We found that the optimum condition was at temperature of 52 °C, reaction time of 30 min, and mass ratio of tetrahydrofuran to methanol of 1.4:1 to achieve a biodiesel yield of 97 %. The result suggests that the addition of tetrahydrofuran as a co-solvent accelerated the transesterification reaction of rubber seed oil with an excellent biodiesel yield.