Conformational equilibria in n-alkanols. Infrared spectral deconvolution of the unsymmetric hydroxyl band profile

Abstract

The uncertainty in the separation of the asymmetric profile of the hydroxyl band of normal alcohols has been overcome by the use of a Fourier deconvolution technique which determined component-band parameters to carry out the band separation unambiguously. The nearly similar rotamer population of trans : gauche of 1.6 : 1 in the n-alcohols showed that the n-alkyl chain does not hinder the rotation around the C—O bond. The enthalpy change of gauche–trans conversion in solution (ca. 7 kJ mol^–1) was much larger than the torsional barrier in the gaseous state.