Catalysis

Phase (matter)

Engineering

Ketone

Photochemistry

Materials science

Cyclohexanol

Solvent

Cyclohexanone

Inorganic chemistry

Chemical engineering

Thermodynamics

Physics

Organic chemistry

Oxygen

Partial pressure

Partial oxidation

Chemistry

Selectivity

Cyclohexane

Liquid phase

Journal of Molecular Catalysis A Chemical

V2O5/Al2O3 exhibits the high selectivity to partial oxidation compounds (cyclohexanol and cyclohexanone) as compared with TiO2 in the photo-oxidation of cyclohexane in the liquid phase. This reaction is an environmentally friendly reaction since it proceeds at ambient temperature and atmospheric pressure without a solvent. The features of the reaction are a high selectivity to partial oxidation products and a reasonable ketone/alcohol ratio (K/A ratio). However, by elongation of the photoirradiation time, cyclohexyl hexanoate as a by-product was generated and the K/A ratio decreased gradually. Retention of the high O2 concentration in the gas phase and irradiation of light λ>330 nm are keys to the selective formation of the partial oxidation compounds with a reasonable K/A ratio in the photo-oxidation of cyclohexane over V2O5/Al2O3. In the present study, a selectivity of 87% to the partial oxidation compounds was achieved with the K/A ratio of 3.8.

Selective photo-oxidation of neat cyclohexane in the liquid phase over V2O5/Al2O3