Excess enthalpies of dibromoalkane + tetrachloromethane mixtures. Measurement and analysis in terms of group contributions (DISQUAC)

Abstract

Blanco S.T. Munoz Embid J. and Otin S., 1993. Excess enthalpies of dibromoalkane + tetrachloromethane mixtures. Measurement and analysis in terms of group contributions (DISQUAC). Fluid Phase Equilibria , 91: 281-290. Excess enthalpies at 298.15 K and atmospheric pressure are reported for binary liquid mixtures of dibromomethane, 1,2-dibromoethane, 1,3-dibromopropane, 1,4-dibromobutane, 1,5-dibromopentane and 1,8-dibromooctane + tetrachloromethane (CCl 4 ). These experimental results, along with literature data, on liquid-vapor equilibria (excess Gibbs energies) are interpreted in terms of the DISQUAC group contribution model. The systems are characterized by three types of contact surfaces: bromine (Br) and alkane, in α,ω-dibromoalkanes, and solvent CCl 4 . The interchange energies of the alkane/CCl 4 and alkane/Br contacts were determined independently from the study of n -alkane + CCl 4 , and α,ω-dibromoalkane + n -alkane systems, respectively. The interchange energies of the alkane/Br contact of dibromomethane and of the Br/CCl 4 contact were estimated in this work. The Br/CCl 4 parameters of α,ω-dibromoalkanes are entirely dispersive and increase regularly with increasing separation u of the two bromine atoms in the molecule (proximity effect) in the same regular manner as observed previously for α,ω-dichloroalkane + CCl 4 , mixtures, and reach the values of 1-bromoalkanes when u ≧ 5. In general, the model provides a fairly consistent description of H E and G E as a function of composition and dibromoalkane chain length.