Aerobic Assymetric Oxidation of Sec-Phenethyl Alcohol in Co2 Expanded Media

Aerobic oxidation reactions are of special interest in industry and in academia because oxygen is environmentally benign and relatively inexpensive. Aerobic oxidation can be applied to various important processes, including various asymmetric reactions, which have special potential to be useful in pharmaceuticals. However, reaction rates for aerobic oxidation reactions are often low because of the limited solubility of oxygen in organic solvents. Because of this, the reactions must be run at high temperature, which results in a decreased reaction efficiency, or high pressure, which raises safety concerns. By using carbon dioxide expanded liquids, it is possible to increase the solubility of oxygen in the organic solvent and provide a non-flammable reaction medium. This study demonstrates the use of the asymmetric aerobic oxidation of sec-phenethyl alcohol to acetophenone using various catalysts in carbon dioxide expanded solvents. It shows that the reactions proceed more rapidly in the expanded medium with higher conversion and selectivity for a given time and temperature.