Deep eutectic solvents – Versatile chemicals in biodiesel production

Due to booming economies, a sharp increase in energy requirements is anticipated worldwide, primarily in the transportation sector. Biodiesel’s aptness in substituting petro-diesel conveniently has pushed research toward more on economically and environmentally benign production technologies. Deep eutectic solvents (DESs), a sub-class of ionic liquids have gained wide popularity in various fields of biodiesel production because of process competence and environmental benevolence. This present study specifically summarizes the application of DESs as a catalyst, cosolvent and extracting solvent in biodiesel production. Sequentially, we first discuss the extraction of lipids, valuable compounds, feedstock pre-treatment, transesterification, and ester purification. Overall DESs in all roles show good performance and recyclability. Based on the findings of this study, we highlight areas where deep eutectic solvents require more research and identify future possibilities. It is suggested that a fully DESs-based biodiesel production scheme is possible.