Study On Electrosynthesis Process Of Several Aromatic Aldehydes

Aromatic aldehydes are very important intermediates in fine chemicals and are widely used in pharmaceutical,pesticide and dye industries.The electrochemical synthesis of aromatic aldehydes was determined by studying the electrochemical synthesis methods of aromatic aldehydes.The synthesis of five kinds of aromatic aldehydes?p-methyl benzaldehyde,m-methyl benzaldehyde,p-fluorobenzaldehyde,p-chlorobenzaldehyde and m-phenoxybenzaldehyde?was studied systematically from two routes of indirect and direct electrosynthesis.The quantum chemical parameters of five raw aromatic hydrocarbons were calculated and the optimization of experimental conditions was theoretically guided.Synthesis of aromatic aldehydes by indirect electrooxidation:Mn²⁺in sulfuric acid electrolyte system was oxidized to Mn³⁺by electrochemical oxidation in a homemade diaphragm electrobath,and then the aromatic hydrocarbons were oxidized to five target aromatic aldehydes.After the optimization of the reaction conditions,a better process for indirect electrosynthesis of aromatic aldehydes was obtained.Through the study on the coordination of electrolytic oxidation reaction process and matrix oxidation process,the recycling of electrolyte was realized and environmental pollution was reduced.Synthesis of aromatic aldehydes by direct electrooxidation:The synthesis process of aromatic aldehydes by two-phase electrolysis was studied in h-type electrolysis cell by direct electrooxidation.The method is simple in operation,easy in condition control and convenient in post-treatment.The front-line molecular orbital parameters and NPA charge distribution parameters of aromatic substrates were calculated by Gaussian 09.The HOMO and LUMO energy levels of the compounds and the net charge distribution of the compounds were analyzed,and the optimization of experimental conditions was theoretically guided.The structures of products by the two methods were characterized by ¹H NMR and HPLC.