Thermochemical kinetics of bromine nitrate, bromine nitrite, halogen hydroperoxides, dichlorine pentoxide, peroxycarboxylic acids, and diacyl peroxides

Abstract

Heats of formation of BrONO_2, BrONO, BrOOH, FOOH, FOOCl, CF_3C(O)OOH, HC(O)OOH, CH_3C(O)OOH, and [CH_3C(O)O]_2 are estimated from bond contributions taken from J. Phys. Chem.,100, 10150 (1996). They agree within ±2 kcal/mol with recent experimental or ab initio data. The resulting BDE(O-O) = 36 kcal/mol value in diacetyl peroxide requires the concerted assistance of exothermic C-C(O) weakening in the transition state of its decomposition into free radicals. It also implies the existence of a previously unrecognized 12 kcal/mol nonbonded repulsion in acyl anhydrides. The formation of chloryl chlorate with ΔH_f(O_2ClOClO_2) = 50 kcal/mol, a marginally stable species toward dissociation into (ClO_3+OClO), may account for observations made in the [O(^3P+OClO] system at low temperatures.

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