Metal-Free Esterification Of Aldehydes With Quaternary Ammonium Salts And Self-Coupling Reaction Of Aldehydes

C-H bond has become one of the most popular study during the organic synthesis chemistry.The activation of C-H bonds is both simple and atomic economically.It provides a powerful tool for creating new organic molecular structure and further modifying the complex organic molecules.It makes study on C-H bond activation more significant and challenging.This paper consists of two parts: metal-free esterification of aldehydes with quaternary ammonium salts and self-coupling reaction of aldehydes.Investigation on the esterification of aldehydes,the reaction mixture was stirred at 120℃ for 24 h in an oil bath.When aldehydes react with quaternary ammonium salts,obtained desired products in yields up to 81%.The result of reaction shows that steric hindrance might play a role in the reaction.The carboxylic acids react with quaternary ammonium salts and obtained desired products in yields up to 90%.Therefore,the esterification of carboxylic acids with quaternary ammonium salts is more efficient and practical.Investigation on the synthesis of 1,2-diketones from the self-coupling reaction of aldehydes,use the supported Palladium nanoparticles which were prepared by a modified impregnation-reduction method as a catalyst,use 4-Chlorobenzaldehyde as a model substrate,exploring the reaction conditions,such as additives,oxidants,solvents and temperature.