Photochemical Reactions of Uranyl Ions with Organic Compounds. II. The Mechanism of the Photo-Oxidation of Alcohols by Uranyl Ions

Quantum yields were measured under various conditions for the photo-oxidation of aliphatic alcohols by uranyl ions in aqueous solutions and kinetic treatments were made. The measurements of uranyl fluorescence quenching by the alcohols showed that a complex formation between uranyl ions and alcohol molecules prior to the photolysis is not likely to be involved. The temperature effect on the quantum yield is strong evidence for a collisional energy transfer from the excited uranyl ions to the alcohol molecules. The relative rates of the photolysis of four isomeric butyl alcohols, and the isotope effect on the photo-reactivity by using alcohols labeled with deuterium, showed that the alcohol molecules are attacked on the α-hydrogen atom as a primary photochemical act.