间接电合成芳香醛反应机理的研究

Studies on mechanism of synthesis of aromatic aldehyde by indirect electrooxidation

利用红外光谱(IR)研究了槽外合成对甲氧基苯甲醛和对溴苯甲醛的反应机理,结果证明:在Ce4+与对取代甲苯的氧化反应中,苯环上甲基被Ce4+氧化的难易受苯环上对位取代基的影响.对甲基苯甲醚先氧化成对甲氧基苯甲醇,再氧化成对甲氧基苯甲醛并最终氧化成对甲氧基苯甲酸,第一个电子传递步骤为控制步骤;对溴甲苯先氧化成对溴苯甲醇,再氧化成对溴苯甲醛,后者为控制步骤.

The mechanism of outside cell reaction of electrosynthesis of p-methoxybenzaldehyde and p-bromobenzaldehye is studied by Fourier-transform infrared (FTIR) absorption spectra. As the results show,an investigation of the reaction of Ce4+ with p-methoxytoluene reveals that the reaction proceeds in well-defined separated steps to p-methoxybenzyl alcohol, p-methoxybenzaldehyde and,eventually, to p-methoxybenzoic acid. Transferring first electron is a controlling step.The reaction of Ce4+ with p-bromotoluene reveals that the reaction proceeds in well-defined separate steps to p-bromobenzyl alcohol,p-bromobenzaldehyde.The last step is a controlling one.