Rice husk ash (RHA): A Highly efficient solid acid catalyst for the oxidation of alcohols and trimethylsilyl, tetrahydropyranyl and methoxymethyl ethers with CrO3

A mild, efficient and fast method for the oxidation of alcohols and trimethylsilyl, tetrahydropyranyl and methoxymethyl ethers to their corresponding carbonyl compounds using CrO3 in the presence of rice husk ash (RHA) is reported. All reactions were performed at room temperature in high to excellent yields. A new, efficient and green catalyst, heterogeneous reaction conditions, easy work-up of the products and high reaction rates are the main advantages of this method.