Factor analysis as a complement to infrared band resolution. VII. The temperature dependence of the self association of phenol in carbon tetrachloride solution

Abstract

Infrared absorption bands in the OH stretching region of phenol in carbon tetrachloride solution have been recorded for various concentrations and at several temperatures between 25 and 60 °C. Factor analysis of the digitized spectra was carried out and the presence of three absorbing components in the OH stretching band was indicated at all temperatures in the range of 25–60 °C. The three components are assigned to monomer, linear dimer, and a polymeric species. It is suggested that the polymeric species is a cyclic trimer.Band contour resolution was carried out to obtain areas of the component bands. The variation of the monomer and dimer band areas with temperature was used to obtain a value for the enthalpy of dimerization of −15.8 ± 0.6 kJ mol−1.