Liquid-Phase and Solventless Oxidation of Cyclohexane, Benzene, and Other Hydrocarbons by Cerium(IV) Catalyzed by Iridium(III) in Acidic Medium

Abstract

Oxidation of some hydrocarbons dissolved in acetic acid by cerium(IV) sulphate at 100 °C in the presence of traces of iridium(III) chloride (catalyst-substrate 1:56818 to 151515) in the solution phase resulted in good to excellent yields of corresponding carbonyl compounds. In the cases of cyclohexane and benzene, 44% and 51.8% yields of corresponding carbonyl compounds were obtained, whereas in other cases, yield ranged from 34.9 to 99.8%. Yield decreased when reactions were performed in a microwave oven by adsorbing reactants (except acetic acid) on alumina. Decrease in the yield was probably due to the high temperature generated during the course of the reaction, resulting in the loss of organics from evaporation. Conditions were optimized for the highest yields under ambient conditions.

Keywords:

• Cerium(IV)
• iridium(III) chloride
• microwave
• oxidation

ACKNOWLEDGMENT

The authors are grateful to University Grants Commission [32–240/2006 (S.R.)] and Council of Scientific and Industrial Research [01(2150)/07/ EMR-II], New Delhi, India, for financial assistance. Help from Central Drug Research Institute, Lucknow, India, is acknowledged for spectral studies.

Notes

Note: Amount of organic substrate a to d (2.0 mmol); e and f (1.0 mmol).