Application of a new statistical mechanical model for calculating Kirkwood factors in self associating liquid systems to alkanol + CCl4 mixtures

Abstract

A recently developed statistical-mechanical model for calculating Kirkwood correlation factors g(K) in self associating liquids and liquid mixtures has been applied for the simultaneous description of g(K) derived from dielectric constant data, the molar enthalpy of mixing H, and the infrared absorbtion of monomeric alcoholic species as function of the composition in alkanol + CCl(4) mixtures. The alkanols are methanol, ethanol, propanol, butan-1-ol, pentan-1-ol, hexan-1-ol, octan-1-ol, sec-butanol, tert-butanol and pentan-3-ol. The majority of parameters involved in the theory are obtained by independent quantum mechanical ab initio calculations of molecular clusters consisting of up to four alcohol molecules. As a consequence only two parameters have to be adjusted freely to each binary system, a third parameter responsible for the non-specific intermolecular dispersion interaction has been adjusted within a limited range of possible values given by physical arguments. Excellent agreement between theory and experimental data for g(K), H and IR absorbance is obtained covering the whole range of concentration. The theory also rationalizes the temperature dependence of these properties without adjusting further parameters. The Kirkwood correlation factor g(K) turns out to be a sensitive response to peculiarities of the molecular structure of hydrogen-bonded systems in the condensed liquid state.