Oxidations catalyzed by metalloporphyrins and metallophthalocyanines

In nature, oxidoreductases - oxygenases, peroxidases and oxidases - are implicated in a wide variety of degradation processes of biopolymers and xenobiotics. It is not surprising, therefore, that metal complexes of biomimetic ligands such as porphyrins and phthalocyanines 

Similarly, Hampton and Ford studied the Fe(PcS)-catalyzed autoxidation of 3,4-dimethoxybenzyl alcohol as a model for delignification. They concluded, however, that the catalyst degrades too fast to be useful for delignification. We also mention, in this context, that water-soluble polyoxometalates such as PV2MoioO have also been used as catalysts for delignification with O2.  

The epoxidation of olefins and the related vicinal dihydroxylation are reactions of great industrial importance. The use of commercially available 30% aq. H2O2 is obviously 

The same system was used for the direct oxidation of cyclohexene to adipic acid, by oxidation with 4 equiv. of 30% aq. H2O2, via the initial formation of cyclohexene oxide (Fig. 7.5). It was further shown that the methodology is apphcable to the oxidative cleavage of a range of cyclic olefins.  

Reedijk and coworkers recently reported a similar system composed of sodium tungstate, tungstic acid and chloroacetic acid together with methyltrioctylammonium chloride as phase transfer agent, which was effective for the epoxidation of olefins with 50% aq. H2O2 without any additional solvent. 

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