Raman spectroscopic study of acetone–phenol mixtures

Abstract

Acetone–phenol mixtures with phenol mole fractions in the range 0.079–0.6000 were studied by Raman spectroscopy. Spectra were obtained in the regions of acetone C=O stretching and C–C symmetric stretching bands. Principal factor analysis applied to the set of C=O stretching bands revealed two independent components belonging to free and hydrogen-bonded acetone. Interaction with phenol produces a new band at a lower wavenumber in the C=O vibration region and an additional band at a higher wavenumber in the C–C symmetric stretch region. These changes were explained by charge delocalization induced by the hydrogen bond. On applying band deconvolution and target factor analysis, it was deduced that the equilibrium constant K of 1:1 acetone–phenol complex formation is too high to be determined by Raman spectroscopy in the range 0.079–0.400 mole fraction of phenol. At equal mole fractions of acetone and phenol, values of K=2.61 and 3.22 dm3 mol-1 were obtained by deconvolution and target factor analysis, respectively. An investigation of ternary solutions with an inert solvent showed no significant differences in acetone–phenol interaction between this system and binary mixtures. © 1998 John Wiley & Sons, Ltd.