Synthesis of vitamin K₃ over mesoporous Zr-MCM-41 molecular sieves

Vitamin K₃ (VK₃) or 2-methyl-1,4-napthoquinone or menadione has been synthesized by selective oxidation of 2-methyl naphthalene (2-MN) with H₂O₂ using Zr-MCM-41(HT, hydrothermal) and Zr-MCM-41(TIE, template ion-exchange) catalysts. Different parameters affecting the oxidation of 2-MN like different Si/Zr ratios of catalysts, amount of the catalyst, reaction temperature, reaction time, 2-MN to H₂O ₂ molar ratio, concentration of acetonitrile and catalyst regenerability are described. In the catalytic reaction, the yield and selectivity of vitamin K₃ in Zr-MCM-41(27)-TIE are higher than that of Zr-MCM-41(27)-HT due to increasing the catalytic activity within pores on the silica surface by completely template-ion exchanging through Zr-ions under TIE method. Thus a Zr-MCM-41(27)-TIE catalyst is the superior catalyst for the synthesis of VK₃.