Oxidation of Cyclohexanol and Cyclohexanone by Monochromate Ions in Organic Solvents and on Solvent Free Microwave Irradiation under Phase Transfer Catalysis - A Comparative Study

Abstract

Oxidation of cyclohexanol and cyclohexanone were carried out by acidified monochromate ions in ethyl acetate and toluene under phase transfer catalysis and also in solvent free condition under microwave irradiation. The extraction of monochromate ions from aqueous medium to organic phase was carried by employing various phase transfer catalysts in the presence of mineral acids. The effect of [catalyst] and [mineral acid] on extraction of monochromate from aqueous phase to organic phase was also studied. The product obtained, namely adipic acid obtained with both reactants was characterized by its melting point and infrared spectral technique. The reaction was over within 15 min with more than 85% yield at a temperature of 323 K under microwave irradiation where as it gave around 70% yield at 353 K within 150 min under phase transfer catalysis condition. The enhanced reaction rate and high yield of product substantiate the application of phase transfer catalytic technique under microwave irradiation for organic synthesis. A suitable mechanism for the oxidation of substrates by monochromate under phase transfer catalysis is also suggested.