On the cationic polymerization of oxirane with triphenylmethylium salts

Abstract 1,4‐Dioxanium and other trialkyloxonium ions were observed by 1 H NMR in the polymerization of oxirane initiated with the triphenylmethyl cation. The major product of polymerization is 1,4‐dioxane. Thus, the kinetic data for the same system previously published by other authors, refer to the propagation in which oxirane propagates with the participation of dioxanium and/or other unstrained trialkyl oxonium cations. Our present results, together with previous data of León et al., indicate that the rate constants of propagation with these two kinds of species are very close to each other. Propagation with participation of the oxiranium ion probably takes place only at the very beginning of polymerization.