Liquid-vapor phase equilibrium in solutions of oxygen and nitrogen at pressures below one atmosphere

Abstract

Data are given for the vapor and liquid compns., the cohesive energy ds., and total vapor pressures of solns. of O and N along isotherms at 77.5, 70, and 65°K. The activity coeffs. of O and N are represented by an equation of the form (R T / V) loge γ = A12 φ2, where φ is the mole fraction of the gas in soln. and A12 = (C11 + C22 - 2 C12), where C11 and C22 are the cohesive ds. of the pure components and C12 results from the interaction of the 2 different tools. A12 in cal./cc. mole has the values 1.22 at 77.5°K., 1.38 at 70°K., and 1.47 at 65°K. The data are not entirely consistent with the assumption that molar vols. are additive in the solns. The deviations of the solns. from ideality are much less than is to be expected of regular solns. in which the interaction energy between unlike mols. follows a geometric mean law. A cryostat and equil. vessel with a novel sampling device are described. [on SciFinder(R)]