Molecular acoustics. Part 7.—Ring inversion and internal rotation in some 2-halomethyl-1,3-dioxans

Abstract

A double ultrasonic relaxation has been observed in some 2-halomethyl-1,3-dioxans. Using n.m.r., infra-red and previous knowledge of the ultrasonic relaxation behaviour of simple 1,3-dioxans the two relaxations have been assigned, in turn, to the perturbation of conformational equilibria involving ring inversion and internal rotation. From the temperature dependence of the relaxation times the barriers opposing these conformational changes have been derived.