Optimizing the production of biodiesel from palm olein (Elaeis guineensis Jacq.) using a strong basic anionic resin as a heterogeneous catalyst

•Purolite A503S resin can be used as catalyst in transesterification reactions.•The replacement of Cl− by OH− in the resin is necessary for its use in the reaction.•For high conversions, the reaction time with Purolite A503S as catalyst is 10 h.•Purolite A503S showed no physical damage, when agitated for 50 h.•98 % conversion was achieved in optimal condition with Purolite A503 as catalyst.