THE OXIDATION OF PENICILLIN-G-POTASSIUM SALT USING SUPPORTED POLYOXOMETALATES WITH HYDROGEN-PEROXIDE

The oxidation of the sulfide group in penicillin G potassium salt to t he sulfoxide with hydrogen peroxide has been investigated using a wide range of polyoxometalates immobilized on high-surface-area supports. The highest activity and selectivity for the sulfur oxidation of the p enicillin compound was obtained with ammonium molybdate supported on t o strongly basic anion-exchange resin. The oxidation proceeds smoothly at ambient and sub-ambient temperatures in water or water/alcohol sol vents. The use of supported oxidation catalysts has been extended to t he transformation of benzenethiol to benzenesulfonic acid which was fo und to proceed in high yield and selectivity employing phosphotungstic acid on gamma-alumina. The use of a supported catalyst with H2O2 as t he primary oxidant allows the circumvention of environmental and produ ct isolation problems to be overcome simply and economically.