Aerobic oxidation of alcohols in carbon dioxide with silica-supported ionic liquids doped with perruthenate

The replacement of toxic and carginogenic chromium (VI) and bioaccumulating chlorinated solvents used in the oxidation of alcohols with oxygen and carbon dioxide (or ionic liquids) remains hindered by the low selectivity and activity of the heterogeneous catalysts developed thus far. We have developed an integrated method that combines entrapped perruthenate, as highly selective aerobic catalyst, with encapsulated ionic liquid, as solubility booster, and supercritical carbon dioxide as reaction solvent. The system is capable of converting a variety of organic alcohols into carbonyl compounds with complete selectivity, including substrates normally difficult to oxidise such as long-chain primary aliphatic alcohols. The technology opens up the opportunity for rapid, waste-free and economically convenient conversion of carbinols into commercially valuable aldehydes and ketones enabling noxious substances to be eliminated from employment in the synthesis of fine chemicals.