The kinetics of ionic polymerisation. Part XIV. Conductivities and visible spectra of iodine–n-butyl vinyl ether mixtures

Abstract

The system iodine–n-butyl vinyl ether in carbon tetrachloride, diethyl ether, and ethylene dichloride has been studied. The species l₄ exists in solutions of iodine in these solvents but is probably not significant in the polymerisation.

The absence of any spectral evidence for l₃^– in polymerising solutions in carbon tetrachloride and diethyl ether suggests that the stationary state concentration of active monomer during polymerisation is only very small. The low conductivities of solutions of iodine and monomer in carbon tetrachloride are in accord with this conclusion.

The first and second ionisation potentials of n-butyl vinyl ether are reported. The predicted absorption maxima of the n-butyl vinyl ether–iodine σ- and π-complexes show poor agreement with the experimentally observed absorption bands which have previously been attributed to these complexes. Conductivity measurements show that the termination of polymerisation is accompanied or followed by large increases in the concentration of ions in the solutions. During polymerisation the conductivities of ethylene dichloride solutions are much higher than those of carbon tetrachloride solutions in accord with the higher dielectric constant and the greater rates of polymerisation for the former.