Gas Solubilities (CO2, O2, Ar, N2, H2, and He) in liquid chlorinated methanes

Gas solubilities (CO2, O-2, Ar, H-2, N-2, and He) in two liquid chlorinated methanes (dichloromethane and chloroform) from 283.15 K to 323.15 K were determined by measuring the decrease in pressure due to absorption. For all gases except for CO2, Henry's law constant decreased with increasing temperature in both solvents. The order of solubility of the gases was CO2, > O-2, > Ar > H-2 > N-2 > He in dichloromethane and CO2 > Ar > O-2 > H-2 > N-2 > He in chloroform. On the basis of the measurements, semiempirical correlations for the solubility in that temperature range were then determined. The measured solubility data were theoretically analyzed using the method proposed by Wilhelm and Battino (J. Chem. Thermodyn. 1971, 3, 379; J. Chem. Thermodyn. 1971, 3, 743). to reveal the molecular basis of the solubility. The resulting theoretical Lennerd-Jones (LJ) potential parameters for both liquids are higher than those for methane but lower than those for carbon tetrachloride. The theoretical analysis also revealed that (a) interaction between the nonpolar gases tested in this study and the solvent liquid depend mainly on the dispersion interaction between solvent molecules and gas molecules, despite a dipole moment in liquid dichloromethane and chloroform and (b) temperature dependence of Henry's law constant for CO2 depends on the energetic effect, whereas that of the other gases (O-2, Ar, H-2, N-2, and He) depends on the entropic effect.