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Catalytic Mechanism of Cu 2+ and Fe 3+ in Alkaline O 2 Oxidation of Lignin

1995; Taylor & Francis; Volume: 15; Issue: 2 Linguagem: Inglês

10.1080/02773819508009507

1532-2319

Guoxiong Wu, Michèle Heitz,

Oxidative Organic Chemistry Reactions

Abstract The catalytic mechanisms of Cu2+ and Fe3+ in the alkaline oxidation of lignin are discussed. Best aldehyde yields were obtained by using Cu2+ and Fe3+ as catalysts. Without these two ions present or in the absence of one or other of them, yields were lower. It is clear that Cu2+ and Fe3+ significantly influence the reactions. Cu2+, acting as the electron acceptor, accelerates the formation of the phenoxy radical, thus speeding up the radical reaction. In order to interpret the effect of Fe3+ on oxidative degradation of lignin and formation of aldehydes, formation of an intermediate, O2-Fe3+-lignin complex and its catalytic mechanism have been proposed.