Reactivity of Radicals and Molecules in Radical Reactions

A survey is made of the effect of polar interactions, due to substituents and the medium, on the reactivity of radicals and molecules in radical additions (polymerisation of monomers), and the metathesis and decomposition of molecules. Analysis of experimental information by the perturbation method leads to the conclusion that the reactivity of radicals increases, while that of molecules falls, with increase in their electronegative properties produced by the introduction of substituents, interaction with the solvent, etc. The non-additivity of the polar effect of substituents, which is known from the copolymerisation of vinyl monomers, is apparent also in several other reactions. A list of 94 references is included.