Ecofriendly metal-free olefins epoxidation and alcohol oxidation by in situ generated poly(peroxybenzoic acid) as a heterogeneous recyclable catalyst under mild conditions: an in-depth mechanistic study

Abstract

In this study a mild and selective protocol was introduced for the alcohol oxidation and alkene epoxidation as two vital reactions in organic synthesis. Poly(benzoic acid) (PBA), a synthetic polymer, was used for the preparation of highly active poly(peroxybenzoic acid) (PPBA) in situ in the presence of H₂O₂. At ambient temperature, alcohol (primary) oxidation proceeds to carboxylic acid selectively (81–99% selectivity), and in 0 °C, aldehyde was the selective product (90–98% selectivity). Alkene epoxidation was also performed in 0 °C with high selectivity. The catalyst was compatible towards a wide variety of alcohols and alkenes substrates like acid sensitive substrates. PBA is used in the reaction at a catalytic rate and, in the presence of H₂O₂, which provides the oxygen necessary for oxidation, is converted to catalytically active PPBA species and reintroduced into the catalytic cycle. The mechanism of the oxidation and epoxidation processes was studied deeply. PBA could be recycled for several times without loss of catalytic activity.