Superior biodiesel production via K2CO3-modified hierarchical Mg-Al hydrotalcite catalyst: Achieving near-complete yield in minutes

A highly dispersed K₂CO₃-based catalyst was synthesized using templated hydrotalcites derived from wormlike micelles as a support material, and its efficacy was demonstrated in the tri-component coupling transesterification process for biodiesel production, utilizing methanol, vegetable oil, and methyl acetate. Within a brief reaction time of 6 min, a remarkably high yield of biodiesel (99.7 %) was achieved using a 10 wt% loading of K₂CO₃/Mg-Al catalyst and a 1:1:12 M ratio of rapeseed oil, methyl acetate, and methanol, respectively, at a relatively low reaction temperature of 55 °C. The hierarchical structure of the templated Mg-Al hydrotalcite support was found to enhance the exposure of basic sites, as evidenced by the characterization of the K₂CO₃/Mg-Al catalyst. This structural feature significantly bolstered the activation of various reactant molecules. A comprehensive kinetic study was conducted, revealing that the transesterification process over the templated layered double hydroxide (LDH) catalyst is predominantly governed by chemical reaction kinetics rather than diffusion limitations. This works offers substantial support for the efficient utilization of natural oils and fats in the production of clean fuels, highlighting the potential for scalable and sustainable biodiesel synthesis.