The flash photolysis of oximes

Abstract

The flash photolysis of formaldoxime and acetaldoxime has been studied under isothermal and adiabatic conditions. The predominant primary photochemical reaction produces R1RsCN. and OH free radicals. Isothermal experiments show that R1R2CN* radicals are not very reactive, whereas H-atom abstraction by OH is fast OH+CH 2 NOH = H 2 O + CHNOH k 300 K = 3.8 x 10 8 1mol -1 s -1 (±50% ) OH + CH 3 CHNOH = H 2 O + CH 3 CNOH k 300 K = 1.3 x 109 1mol --1 s -1 (±50% ). Under adiabatic conditions, the oximes decompose by a short chain mechanism with OH as the chain-propagating radical. Nitric oxide accelerates the decomposition by sensitizing the production of hydroxyl radicals.