Radiation Chemistry and Photochemistry of Oxychlorine Ions: Part 2.—Photodecomposition of Aqueous Solutions of Hypochlorite Ions

Abstract

The photodecomposition of alkaline aqueous solutions of hypochlorite ion has been investigated using steady state and flash photolysis techniques. At 365 nm the primary products are O(3P), O–, Cl and Cl– formed by the following processes [graphic omitted] with ϕa= 0.28 ± 0.03 and ϕb= 0.08 ± 0.02. At 313 nm and 253.7 nm O(1D) is also produced ClO–→ Cl + O(1D)(c) and the quantum yields are ϕa= 0.075 ± 0.015, ϕb= 0.127 ± 0.014, ϕc= 0.020 ± 0.015 at 313 nm, and ϕa= 0.074 ± 0.019, ϕb= 0.278 ± 0.016, ϕc= 0.133 ± 0.017 at 253.7 nm.

The relative rates of reaction of O(3P) with O2, ClO– and ClO–2 have been found to be in the ratios 1 : 2.8 : 15.9. O(3P) reacts with ClO– and ClO–2 by abstraction of O as well as by addition. A complete reaction mechanism for the photodecomposition of ClO– is proposed.