Free Radicals in Solution

Abstract

WITHIN recent years numerous investigations have proved beyond doubt the existence of free alkyl and aryl radicals, which are formed in the gaseous phase by the thermal or photochemical decomposition of suitable organic molecules. More recently, Norrish and Bamford¹ have devoted their attention to the production of free alkyl radicals in solution and have shown that the alkyl radicals R and R', formed by the photodecomposition of a ketone RCOR', do not combine together, as in the gaseous phase, thus: R + R RR' ; R + R↦RR and R' + R' ↦ R' R', but mainly react with the solvent by abstraction of hydrogen with the formation of the simple hydrocarbons RH and R'H. Further, Walker and Wild² have studied the photodecomposition of diacetyl peroxide in solution (Cyclohexane or ethyl alcohol) and have shown that more methane and less ethane is formed under these conditions than when the decomposition is effected in the absence of a solvent. This reaction would also appear to involve the production of free alkyl radicals, which again have the characteristic property of abstracting hydrogen from the solvent.