One‐pot solvent‐free transformation of natural triglycerides to ester and amide derivatives over CaO@KC nanostructured catalysts

Abstract

Summary In the present report, the fatty acid alkyl esters and fatty acid amides were synthesized from natural triglycerides by highly selective solvent‐free one‐step methods using 3.5‐CaO@KC‐400 nanocrystals as a heterogeneous catalyst. A modified wetness chemical impregnation method was used to prepared potassium carbonate‐doped CaO, ZnO, and MgO nanocrystals. The prepared 3.5‐CaO@KC‐400 nanocrystals were found as the most efficient heterogeneous catalyst (5%, w/w) for amidation (6:1 M ratio of diethanolamine/oil, 110°C) and transesterification (12:1 M ratio of methanol/oil, 65°C) of waste cooking oil and took 30 minutes for the completion of both the reactions. The 3.5‐CaO@KC‐400 nanocrystals were found to be efficient at room temperature also and reused for 10 reaction cycles for both reactions. The pseudo‐first‐order kinetic model was applied and the first‐order rate constant was calculated as 0.15 minute−1 and 0.103 minute−1 for the amidation and transesterification reactions of waste cooking oil, respectively.