23: Photochemical aerobic oxidation of benzylic alcohols for the production of hydrogen peroxide

Abstract: Hydrogen peroxide (H2O2) is widely used as a green oxidant and antiseptic in industry. Recently, it has emerged as a promising renewable fuel for use in H2O2 fuel cells. However, current manufacturing practices are energy intensive and rely on the use of H2 and Pd to catalyze the reaction. Photochemical methods offer an exciting alternative to H2O2 generation by making it possible to use solar energy to drive the reaction. Several methods exist for the photocatalytic production of H2O2 but require rare earth metals or complex organic synthesis and cannot be scaled to industry standards. I present a novel method that makes use of Rose Bengal, an organic singlet oxygen photosensitizer, to initiate the N-hydroxyphthalimide catalyzed aerobic oxidation of benzylic alcohols and production of H2O2. Oxidation and H2O2 production rates were shown to be higher for benzylic alcohols substituted with electron donating groups. The highest rate of oxidation and H2O2 production was found for 4-methoxybenzhydrol with a rate of 13.1 (mmol/L*h) and 10.8 (mmol/L*h) respectively. These method offers an alternative mechanism for H2O2 production that utilizes simple organic molecules with the potential for large scale photochemical production of H2O2.