EXCESS-ENTHALPIES OF DIBROMOALKANE PLUS TETRACHLOROMETHANE MIXTURES -MEASUREMENT AND ANALYSIS IN TERMS OF GROUP CONTRIBUTIONS (DISQUAC)

Excess enthalpies at 298.15K and atmospheric pressure are reported for binary liquid mixtures of dibromomethane, 1,2-dibromoethane, 1,3-dibr omopropane, 1,4-dibromobutane, 1,5-dibromopentane and 1,8-dibromooctan e + tetrachloromethane (CCl4). These experimental results, along with literature data, on liquid-vapor equilibria (excess Gibbs energies) ar e interpreted in terms of the DISQUAC group contribution model. The sy stems are characterized by three types of contact surfaces: bromine (B r) and alkane, in alpha,omega-dibromoalkanes, and solvent CCl4. The in terchange energies of the alkane/CCl4 and alkane/Br contacts were dete rmined independently from the study of n-alkane +CCl4 and alpha,omega- dibromoalkane + n-alkane systems, respectively. The interchange energi es of the alkane/Br contact of dibromomethane and of the Br/CCl4 conta ct were estimated in this work. The Br/CCl4 parameters of alpha,omega- dibromoalkanes are entirely dispersive and increase regularly with inc reasing separation u of the two bromine atoms in the molecule (proximi ty effect) in the same regular manner as observed previously for alpha ,omega-dichloroalkane + CCl4 mixtures, and reach the values of 1-bromo alkanes when u greater than or equal to 5. In general, the model provi des a fairly consistent description of HE and GE as a function of comp osition and dibromoalkane chain length.