Influence of reaction conditions on product distribution in the green oxidation of cyclohexene to adipic acid with hydrogen peroxide

The effect of reaction conditions (such as the amount of sulfuric acid, reaction temperature and feeding style of reactants) on the product distribution in the green oxidation of cyclohexene to adipic acid was investigated. This reaction, with 30% hydrogen peroxide as oxidant in the presence of a homogeneous peroxy tungstate catalyst, is of great industrial interest for not using of organic solvent and phase-transfer catalyst. The synthesis we investigated produces adipic acid as the product, glutaric acid and succinic acid as main byproducts, and cyclohexanediol is an intermediate. Using this green method, a 94.5% yield of adipic acid has been achieved while byproducts and intermediates could be reduced. Finally, a proposed mechanism for the formation of glutaric acid was suggested, it was also supported by density functional theory calculations.