Spectroscopic studies of the “free” OH stretching bands in liquid alcohols

A detailed investigation of the Raman “free” OH stretching band (3600-3650 cm− 1) of liquid alcohols has been performed. Raman spectra of pure liquids 1-octanol, 2-octanol and tert-butanol have been analyzed as a function of temperature. Relevant spectral features have been consistently explained taking into account the concomitant effect of both rotational isomerism and hydrogen bonding. Important indications on the alcoholic liquid structure have been obtained following spectral modifications induced by the apolar 2,2-dimethylbutane solvent on the liquid tert-butanol. Further, the Raman “free” OH stretching band has been employed to explore structural properties of the tert-butanol/water system in the alcohol-rich region. The deduced hydration mechanism initially involves interaction of water molecules with tert-butanol monomers.