木质素的电氧化研究及应用

Study of Electrochemical Oxidation of Lignin and its Application

综述了木质素的电氧化机理研究及其应用。木质素的电氧化有两种机理 ,一种是失去两个电子产生苯氧正离子 ,然后苯氧正离子与水或甲醇反应 ;而在碱性介质中 ,倾向于发生单电子转移 ,产生苯酚自由基 ,然后形成碳碳双键。在一定条件下 ,电氧化会导致苯环的减少和羧基的增加 ,具有脱甲氧基的作用。木质素的电氧化可应用于木质素功能化、木质素降解、纸浆的漂白和废水漂白。

Mechanism studies and application of electrochemical oxidation of lignin are reviewed in this paper.There are two kinds of mechanism:one is to form phenoxonium ion by the removal of two electrons.Subsequent reactions with methanol and or water were found.The other,which is favored in solutions containing base,is a one-electron reaction producing the phenoxy radical and resulting in carbon-carbon coupled products.Electrochemical oxidation would lead to a decrease of the phenyl groups and increase of the carboxylic groups of lignin.And it would also cause a decrease of methoxyl group.Electro-oxidation of lignin can be use in the fields of the functionallization and degradation of lignin, the bleaching of pulp and waste-water.