Biodiesel production from used cooking oil by two-step heterogeneous catalyzed process

▸ An economical and eco-friendly two-step heterogeneously catalyzed process for biodiesel production is presented. ▸ The process is applicable to oil feedstocks containing high free fatty acids. ▸ Very cheap used cooking oil is taken as feedstock and high yields of biodiesel are achieved. ▸ The solid catalysts used are highly active and reusable for both esterification and transesterification reactions.