Solvent-free K–CaO/Ca(OH)₂ mixed-phase nanocatalytic single-step methanolysis, ethanolysis and aminolysis of Pongamia pinnata triglycerides

In this report, the K–CaO/Ca(OH)₂ mixed-phase nanodendrites were prepared and used as a heterogeneous catalyst for the one-pot solvent-free synthesis of methyl esters, ethyl esters and alkyl amides from Pongamia pinnata triglycerides. A modified incipient-wetness chemical impregnation method was used to prepared potassium hydroxide doped CaO, MgO, and ZnO nanocrystallites. The prepared K–CaO/Ca(OH)₂ nanocrystallites were found as the most efficient heterogeneous catalyst (4%, w/w) for aminolysis (6:1 M ratio of diethanolamine/oil, 110 °C), methanolysis (9:1 M ratio of methanol/oil at 65 °C) and ethanolysis (9:1 M ratio of ethanol/oil at 75 °C) of Pongamia pinnata oil and took 40 min for the completion (99% yield) of all the reactions. The K–CaO/Ca(OH)₂ nanodendrites were found to be efficient at room temperature (25–30 °C) also and reused for 10 reaction cycles. The pseudo-first-order reaction kinetic model was applied and the first-order rate constant was calculated as 0.112 min⁻¹, 0.093 min⁻¹, and 0.118 min⁻¹ for the methanolysis, ethanolysis, and aminolysis of Pongamia pinnata oil, respectively.