The oil from the Capparis spinosa (CS) plant is explored as a promising source for biodiesel production via an ester exchange reaction in a continuous system under supercritical methanol (SCM) conditions. This approach eliminates the need for a catalyst, significantly reducing mass transfer resistance and shortening reaction times, thereby enhancing biodiesel synthesis efficiency. Adding carbon dioxide as a co-solvent optimizes the process by lowering temperature and pressure while reducing alcohol consumption. This study examines the impact of four key parameters (methanol-to-oil weight ratio, temperature, time, and pressure) on biodiesel production efficiency using SCM. Carbon dioxide is employed as a solvent, with its thermodynamic and structural properties analyzed and compared to experimental data from B3LYP/6-311++G(d,p) calculations. Biodiesel production occurs within a pressure range of 190–340 bar and a temperature range of 510–680 K to identify optimal conditions for maximum efficiency. Results show that higher pressure enhances extraction efficiency, while elevated temperatures at constant pressure reduce SCM density, affecting oil solubility and viscosity. The optimal conditions identified include a methanol-to-oil molar ratio of 34, a temperature of 637 K, a pressure of 297 bar, and a reaction time of 90 min, achieving biodiesel production efficiency exceeding 99%.
Leila Mahdavian (Fri,) studied this question.