Mass spectrometry study of intermediates in thermal decomposition of perchloric acid and chlorine dioxide

Abstract

The thermal decomposition of 72 % perchloric acid produced mainly ClO and ClO₂. A much smaller yield of ClO radicals was obtained from the thermal decomposition of chlorine dioxide. It is suggested that the ClO radicals in the acid decomposition were derived mainly from the decomposition of ClO₃ radicals ClO₃→ClO+O₂, (4) and production of ClO₂ to arise by the alternative reaction ClO₃→ClO₂+O, (3) although reaction (3) is thermodynamically less favourable than reaction (4). Electron impact studies on chlorine dioxide and ClO radicals gave a value for D(O—ClO) of 55 ± 2 kcal mole^–1. The ionization potentials of ClO₂ and ClO were measured directly as 10.7 ± 0.1 and 11.1 ± 0.1 eV respectively.