HEAT-CAPACITIES AND CONCENTRATION FLUCTUATIONS IN MIXTURES OF 1,2-DIBROMOETHANE WITH ALKANES

Excess volumes, excess heat capacities and light scattering have been measured for several 1,2-dibromo-ethane-alkane (n-heptane, n-octane, n -tetradecane, cyclooctane and 2,2,4-trimethylpentane) systems. The res ults show that there is good agreement between values of the concentra tion-concentration correlation function S-cc, as calculated from light -scattering data, and the predictions of the simple rigid lattice mode l of Flory and Huggins, which estimates the relative effects of the di fferences in molecular sizes and of differences in the interaction ene rgies of the two components. The results also confirm the utility of S -cc as predictor of the existence of W-shaped excess isobaric heat cap acity (C-p(E)) curves, although other effects, such as the destruction of the (partial) correlation of molecular orientation may complicate this issue.