Ultrasonic relaxation and ring inversion in an asymmetric sulphate 4-methyl-1,3,2-dioxathian 2,2-dione

Abstract

The rates of ring inversion in 4-methyl-1,3,2-dioxathian-2,2-dione have been measured in p-xylene solution by the ultrasonic relaxation technique. From the temperature-dependence of these inversion rates the barrier to ring inversion was found to be 4·6 kcal./mole and the entropy of activation was –6·3 cal./mole/deg. In the equilibrium between the axial and equatorial chair isomers 95% of the molecules are in the chair form with the methyl group equatorial at 30°.