A comparative study of the production of methyl esters from non-edible oils as potential feedstocks: Process optimization and two-step biodiesel characterization

• Biodiesel derived from J. Curcas . C. Inophyllum and C. Pentandra oil. • Response surface methodology optimized conditions for biodiesel conversion. • Five factors analyzed: KOH, temperature, molar ratio, reaction time, & agitation speed. • Optimized biodiesel yield for 3 types of different feedstock has achieved > 90 %. • Biodiesels met ASTM D6751 standards and showed diesel-like properties. The growing demand for sustainable and renewable energy sources has intensified interest in biodiesel production from non-edible vegetable oils, offering an alternative to reduce reliance on edible oils. This study focuses on the biodiesel potential of Jatropha curcas, Calophyllum inophyllum, and Ceiba pentandra oils, which are rich in free fatty acids.This study explores the biodiesel potential of Jatropha curcas, Calophyllum inophyllum, and Ceiba pentandra oils, focusing on developing a unified set of process conditions for effectives conversion. The response surface methodology (RSM), a nonlinear regression approach, was employed to optimize the transesterification process, aiming to simulate and apply the same process parameters across all three oils. Five key factors affecting the conversion of biodiesel: molar ratio, potassium hydroxide, temperature, time, and speed agitation, using two-stage analysis of variance. The optimal experimental conditions for the transesterification process were 0.5 wt% of potassium hydroxide catalyst, a temperature at 50 °C, molar ratio of 9:1, time of reaction at 60 min, and agitation speed of 811 rpm. Under these optimal conditions, >90 % biodiesel yield was obtained. The fuel properties of the biodiesel were evaluated and found to meet ASTM D6751 standards, exhibiting characteristics comparable to conventional diesel. These findings demonstrate the feasibility of using non-edible oils under a single optimized process, paving the way for cost-effective and scalable biodiesel production suitable for compression ignition engines.