Thermodynamic study of mixtures containing dibromomethane: Excess and solvation Gibbs energies

Isothermal vapor–liquid equilibria at 298.15 K for dibromomethane + an organic compound (C5–C8 n-alkanes, cyclohexane, tetrachloromethane, diethyl ether, dipropyl ether, dibutyl ether, tetrahydrofuran, and 3-pentanone) were determined by head-space gas chromatographic analysis of the vapor phase. Excess molar Gibbs energies, GE, and activity coefficients for the investigated systems were obtained by a least-square treatment of equilibrium data. All systems except mixtures with tetrahydrofuran and 3-pentanone revealed positive deviations from ideality. The Gibbs energies of solvation, ΔsolvG°, for the examined substances in dibromomethane were evaluated and compared with those in dichlorometane. The effect of polar groups, chain lengthening, and cyclization upon ΔsolvG° was discussed.