Raman and infrared spectra of ethylene glycol

Abstract

The Raman spectrum of ethylene glycol has been investigated in the liquid and solid states and also in aqueous solutions. The infrared absorption spectrum of the liquid has been recorded. 27 Raman lines and 17 infrared maxima in the liquid state and 20 Raman lines in the solid state have been reported. Detailed vibrational assignments have been given. Two strong polarised Raman lines of the liquid which have no corresponding infrared absorption bands, and which disappear on solidification, have been attributed to the trans configuration of the glycol molecule. From a comparative study of the various spectra, it is concluded that in the liquid state, glycol exists as a mixture of the two rotational isomers (trans and gauche) whereas in the solid state only the gauche form is present. In very dilute aqueous solutions, the predominant molecular form is the gauche form.