Zinc peroxide as a convenient and recyclable source of anhydrous hydrogen peroxide and its application in the peroxidation of carbonyls

In this work, ZnO2 was unexpectedly discovered as a friendly and renewable source of anhydrous hydrogen peroxide in the acid-catalyzed synthesis of cyclic organic peroxides from carbonyl compounds. In particular, five classes of cyclic organic peroxides, namely, gamma-hydroperoxy-gamma-peroxylactones, beta-hydroperoxy-beta-peroxylactones, bridged ozonides, bridged 1,2,4,5-tetraoxanes, tricyclic monoperoxides, and tricyclic diperoxides, were synthesized in good yields using in situ generated H2O2 from the reaction of ZnO2 with H2SO4. This approach is convenient, safe, and does not require a concentrated aqueous or ethereal solution of H2O2. The starting ZnO2 was synthesized from zinc acetate using a 1 wt% H2O2 solution. The reaction of zinc peroxide with sulfuric acid in an organic solvent results in the release of hydrogen peroxide and the formation of zinc sulfate, which acts as a desiccant by forming a monohydrate phase, ZnSO4 center dot H2O. The possibility of recycling zinc peroxide from zinc sulfate monohydrate with a high yield was shown. This study reports a convenient, safe and recyclable source of anhydrous H2O2 for organic peroxide synthesis. It is based on the generation of H2O2 through the reaction of ZnO2 with H2SO4 and the recycling of ZnO2 from ZnSO4 and 1 wt% H2O2.