Preparation of 2-Methyl-1,4-Naphthoquinone(vitamin K3) by Catalytic Oxidation of 2-Methylnaphthalene with Sulfuric Acid as Catalyst

The oxidation of 2-methylnaphthalene(2-MN) to 2-methyl-1,4-naphthoquinone(2-MNQ, Vitamin K-3) was accomplished in acetic acid with the application of hydrogen peroxide as oxidant. The yield of 2-MNQ was up to 81.3% when sulfuric acid used as catalyst. The catalyst exhibits excellent substrate conversion and target product selectivity. Different parameters affecting the oxidation of 2-methylnaphthalene with hydrogen peroxide catalyzed by sulfuric acid were described, such as reaction temperature, reaction time, dosage of hydrogen peroxide, and amount of sulfuric acid. Compared with the traditional methods for the preparation of Vitamin K-3 with yield of only 30-50%, this method presented could be more effective, economical and ecofriendly.