Heterogeneous Catalyzed Biodiesel Production Using Cosolvent: A Mini Review

Biodiesel is gaining recognition as a good replacement for typical diesel owing to its renewability, sustainability, and eco-friendly nature. Transesterification is the leading route for biodiesel generation, which occurs during homogeneous/heterogeneous/enzymatic catalysis. Besides this, the usage of heterogeneous catalysts is considered more advantageous over homogeneous catalysts due to the easy catalyst recovery. Consequently, numerous heterogeneous catalysts have been synthesized from multiple sources with the intention of making the manufacturing process more efficient and cost-effective. Alongside this, numerous researchers have attempted to improve the biodiesel yield using heterogeneous catalysts by introducing cosolvents, such that phase limitation between oil and alcohol can be minimized. This short review is aimed at examining the investigations performed to date on heterogeneously catalyzed biodiesel generation in the presence of different cosolvents. It encompasses the techniques for heterogeneous catalyst synthesis, reported in the literature available for heterogeneous catalyzed biodiesel generation using cosolvents and their effects. It also suggests that the application of cosolvent in heterogeneously catalyzed three-phase systems substantially reduces the mass transfer limitation between alcohol and oil phases, which leads to enhancements in biodiesel yield along with reductions in values of optimized parameters, with catalyst weight ranges from 1 to 15 wt. %, and alcohol/oil ratio ranges from 5.5 to 20. The reaction time for getting the maximum conversion ranges from 10 to 600 min in the presence of different cosolvents. Alongside this, most of the time, the biodiesel yield remained above 90% in the presence of cosolvents.