Liquid phase oxidation reactions over MoMCM-41 and WMCM- 41 molecular sieves

摘要

The oxidation of 2-methyl-naphthalene (2MN) to 2-methyl-l,4-naphthoquinone (2MNQ), vitamin K_3 (menadione) was carried out over MoMCM-41 mesoporous molecular sieve catalyst. The typical reaction run was carried out using acetic acid as a solvent, hydrogen peroxide (H_2O_2) as an oxidant, in the temperature range of 60-120℃ for 2-12 h. The liquid product selectivities to 2-methyl-l,4-naphthoquinone were 85, 80, 81 and 79 percent at 12, 69, 98 and ～99 percent conversions of 2MN for the molar ratio of 2MN:H_2O_2 equal to 1:2, 1:4, 1:6 and 1:7 respectively. The effect of the various parameters including reaction temperature, molar ratio of 2MN:H_2O_2, Si/Mo ratio, various catalysts, various solvents, the various molybdenum precursors and amount of catalyst were studied. The selectivity to benzaldehyde was ～99 percent at ～50 percent conversion of styrene over WMCM-41 mesoporous molecular sieve catalyst.