Percarboxylic acids reaction with activators

One example which deserves special mention is the use of a percarboxylic acid such as peracetic acid, generated in situ by autoxidation of the corresponding aldehyde, developed by Murahashi and coworkers, see Eq. (1) [25-27]. These reactions are generally considered to involve high-valent oxoruthenium complexes, generated by reaction of the percarboxylic acid with the ruthenium catalyst, as the active oxidant. 

A new way to prepare peroxy acids was discovered by Novo Nordisk, DK (9-11). They showed that some lipases catalyze the conversion of fatty acids with hydrogen peroxide (preferably 60%) to peroxy fatty acids Novozym 435, an immobilized lipase from Candida antarctica on polyacrylic Lewatit, is the most active and stable biocatalyst for this purpose (Scheme 1). Recently we found that Novozym 435 is also capable of catalyzing perhydrolysis (12), i.e., the reaction of carboxylic acid esters with hydrogen peroxide to percarboxylic acids (Scheme 2). 

Representative examples are shown in Table 5. The results were rationalized by assuming that the corresponding percarboxylic acid is formed by cobalt-mediated free radical autoxidation of the aldehyde. Subsequent reaction of mthenium(m) with the peracid affords oxoruthenium(V) carboxylate which is the active oxidant. Cbmpared to the aerobic oxidations... 

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