In this study, the transesterification of RBDPO into biodiesel was performed in batch mode at a reaction temperature of 65°C, with a stirring speed of 450 RPM, 30% (by weight) methanol, and 2% (by weight) K2CO3 catalyst. The research incorporated independent variables, including reaction time (60, 120, 180, and 240 minutes), and the addition of EFB ash to the K2CO3 catalyst (0%, 1%, and 2% by …