Infrared and Raman studies on meso- and (±)-2,3-dichloro- and -2,3-dibromo-butanes

Abstract

The infrared spectra of liquid and solid meso- and (±)-2,3-dichloro- and -2,3-dibromo-butanes have been measured together with the Raman spectra of the liquids. From this spectral data the vibrational frequencies of some of the rotational isomers have been assigned. The enthalpy differences between all the rotational isomers of both the meso- and (±)-forms have been derived from a temperature study of the optical densities of some infrared bands. The vapour-phase enthalpies can be explained in terms of intramolecular non-bonded intractions whereas in the liquid phase there is strong evidence of intermolecular forces.