Metalloporphyrin catalyzed oxidation of methyl yellow and related azo compounds

Fe(TDCPP)Cl catalyzes the oxidation of simple azo compounds including 4-phenylazoaniline, 4-(phenylazo)-N-methylaniline and 4-(phenylazo)-N,N-dimethylaniline (methyl yellow). Methyl yellow and 4-(phenylazo)-N-methylaniline are N-demethylated to form 4-phenylazoaniline prior to further oxidation. Oxidation of 4-phenylazoaniline generates a variety of products as a result of multiple reaction pathways occurring simultaneously. One pathway for the oxidation of 4-phenylazoaniline involves oxidative cleavage of the azo linkage while additional pathways result in modification of 4-phenylazoaniline without cleavage of the azo linkage. One of these additional reaction pathways includes the formation of an additional azo linkage to yield 1,4′-bis(phenylazo)azobenzene.

Metalloporphyrin catalyzed oxidation of the azo dye methyl yellow is a complicated process. The initial N-dealkylation reactions produce 4-phenylazoaniline which is further oxidized. Oxidative decolorization of 4-phenylazoaniline involves both asymmetric cleavage of the azo linkage and oxidation of the amine group.Figure optionsDownload as PowerPoint slide