Influence of Solvent upon the Energy Difference between Rotational Isomers

Abstract

The energy difference between the rotational isomers of the gauche‐ and trans‐forms of 1,2‐dichloroethane in various solutions have been calculated by use of a modified Onsager's reaction field. The following assumptions have been employed in the calculation: first, the cavity of the solute molecule is spheroidal; second, the dipole moment of the molecule is composed of two point dipoles which are placed at the foci of the spheroidal cavity, the focal distance being taken as equal to the distance between the contact points of the carbon and chlorine atoms in the dichloroethane molecule. The change of energy difference between rotational isomers by solvents thus computed has been found to be in close agreement with the experimental observations, that is, those obtained by infrared absorption measurements as well as dipole moment.