Lewis acids self-ionisation

The self-ionisation equilibrium (Eqn. (1)) is displaced, increasing the proton concentration effectively quantitatively in the case of relatively dilute solutions of SbF5. Weaker Lewis acids such as AsF5 and BF3, which will be described in Sec. 11.2.3.1, cause partial displacement of the equilibrium. 

The above observations are obviously not intended as a rejection of this very useful technique. We shall have numerous opportunities to underline the important contributions made by its judicious exploitation. Perhaps the most interesting application of conductivity in cationic polymerisation relates to measurements in model systems such as the study of the self-ionisation of initiators, the interactions of Lewis acids with cocatalysts, and of course the extent of dissociation of stable carbenium salts. 

The third mechanism which can account for direct initiation involves the self-ionisation of the Lewis acid prior to the attack on the monomer ... 

The obvious explanation of the mechanian of initiation arisii from the self ionisation of Lewis acids, i.e., in the absence of a cwatalyst, is that ccHisisting of the attack... 

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