Optimization and kinetic study of biodiesel production from nyamplung oil with microwave-assisted extraction (MAE) technique

Nyamplung oil (Calophyllum inophyllum), which has a high oil content and non-edible, has a lot of potential as a raw material in the production of biodiesel. Therefore, it has no impact on food security. In this research, response surface methodology was used to find the optimum conditions of biodiesel production from nyamplung, and the kinetics model of esterification reaction of free fatty acid (FFA) in the MAE method was determined. This study used RSM with central composite design (CCD) to find the optimal operating conditions. The RSM optimization with TG recovery shows 95.49% and FFA recovery 31.42% with operating conditions respectively at 423 W and 427 W and extraction time for 40 and 38 min. According to kinetic experiments conducted at various microwave power levels, the conversion of nyamplung into biodiesel follows the first, second, and third-order reactions. According to the data, the maximum R² is found in the second and third-order reactions. It was determined the activation energy and kinetic rate constants. The reaction rate constants significantly increased at 150, 300, and 450 W, namely 0.0005 mol⁻¹, 0.0008 mol⁻¹, and 0.0008 mol⁻¹. Nevertheless, it drops at 600 W to 0.0004 mol⁻¹. It was found that the activation energy value using the MAE method was 604.43 J/mol. This value was smaller than the value of the activation energy using the conventional method, 4831.26 J/mol. It was shown that biodiesel production from nyamplung oil with the MAE method could change the conventional method because it needs less energy and less time. So, the production process is more efficient.