Baeyer-Villiger Oxidation With Hydrogen Peroxide Over Silane Coupling Agent Modified Silica Catalysts

The intermediates of lactones synthesized by Bae yer-Villiger oxidation reaction are widely used in the spices, pesticide, medicine and other fields.The silane coupling agent modified silica catalysts were prepared. Nano-silica or ordinary-silica was used to support phenyl trimethoxy or vinyl trimethoxy silane coupling agent and undergo sulfurication further. The catalysts were characterized by infrared spectroscopy, thermal analysis and scanning electron microscopy.The catalytic activities of silane coupling agent modified silica catalysts were applied to Baeyer-Villiger oxidation reaction with hydrogen peroxide. The conversion of 2-heptylcyclopentanone was 98.9% and the yield of δ-dodecalactone was 95.9% over vinyl trimethoxy silane coupling agent modified silica catalyst at 45℃ for 24 h. Different catalytic of modified nano-silica and ordinary-silica catalysts were discussed. The conversion was 98.8% over phenyl trimethoxy silane coupling agent modified nano-silica at 45℃ for 24 h, while 49.2% over phenyl trimethoxy silane coupling agent modified ordinary-silica under the same reaction conditions. The catalytic activity of different cyclic ketones was studied, the cyclic ketones (2-adamantanone,2-methyl cyclohexanone) with tertiary carbon bonded to the carbonyl carbon have higher yield to the corresponding lactones than those with secondary carbon, conversions were more than 90%. The catalyst was easily recovered and recycling rate was high, the catalytic reaction mechanism was described.