Collect. Czech. Chem. Commun. 1982, 47, 2351-2362

Oligomerisation of methyloxirane initiated by (C6H5)3C+ AsF6-, (C6H5)3C+ SbCl6- and SbCl5

Jiří Vohlídal, Marta Pacovská and Jiří Dvořák

Department of Physical Chemistry, Charles University, Albertov 2030, 128 40 Prague 2


Reactions of methyloxirane with the title compounds lead to the formation of a mixture of cyclic and linear oligomers with average polymerisation degree ranging from 5 to 10. The oligomers are formed by combination of back-bitting reaction with re-initiation of the transiently desactivated reaction centers followed by monomer transfer. The important role which these reactions play in the overall oligomerisation of methyloxirane is due to the fact that in addition to active centres with the structure of oxonium ions, also carbenium active centres participate significantly in the reaction. In the systems with stable pair anions AsF6-, the irreversible termination of active centres does not take place, in contrast to the latter systems. This termination involves the reaction of the cation of active centre with the pair anion which releases one ligand during this interaction. The results obtained indicate that in the systems initiated by SbCl5 the active centres of amphiion structure can play an important role in initial stages of the reaction.