ABSTRACT In this work the use of ionic liquids in the Baeyer-Villiger oxidation of cyclic ketones to lactones, mediated by cyclohexanone monooxygenase, is presented. The influence of the structure of various ionic liquids on the activity of cyclohexanone monooxygenase was studied. The selected cations of the ionic liquids represented a variety of structures: aromatic, cyclic aliphatic, and aliphatic. The anions were chosen from hydrophobic and hydrophilic groups. The activity of the enzyme was found to depend on the cation structure. The best reaction performance was reached via the addition of 17 v/v% 1-butyl-1-methylpyrrolidinium bistriflimide. The complete conversion of 4-methylcyclohexanone to high purity 4-methylcaprolactone (enantiomeric excess 99%, R isomer) was achieved after 2 h.
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