Abstract
A critical examination of polymerization, dimerization, and isomerization experiments carried out under carefully controlled (anhydrous) conditions leads to the conclusion that polymerization, etc. may proceed in purest monomer/Friedel-Crafts halide systems in the absence of coinitiators. Thus the well-entrenched view that Friedel-Crafts halides always require coinitiator (protogenic impurities) for initiation of cationic polymerizations has to be modified. It is postulated that initiation in purest olefin/Friedel-Crafts halide systems might proceed by a self-initiation mechanism involving the abstraction of an allylic H from the monomer by the Friedel-Crafts halide MXn: The chemistry and evidence for this mechanism are discussed in detail.