Ethylene solubility and diffusivity in polar and non polar solvents and solutions.

Abstract

Solubilities of ethylene were measured in the solvents, n-hexane, dodecane, n-butanol, ethylene glycol and carbon disulphide as well as mixed solvent solutions composed of n-hexane-dodecane and n-butanol-ethylene glycol at 25°C and a total pressure of one atmosphere. In addition to this, ethylene solubilities were measured at five different temperatures over a range from -10°C to 70°C. The experimental results were compared with those predicted by theoretical correlations. Solubility variation with temperature was shown graphically by plotting log x versus log T and log x versus l/T. Diffusion coefficients of dissolved ethylene were measured in the solvents n-hexane, dodecane, n-butanol and ethylene glycol as well as in the mixed solvents hexane-dodecane and ethylene glycol-butanol at 25°C using the capillary cell method. Diffusivities were well described by a linear relation between the logarithm of diffusion coefficient and the logarithm of solvent viscosity except for the case of ethylene glycol and ethylene glycol-butanol solutions. The constancy of the product Dsigma2 (sigma being the molecular diameter of the diffusing gas) was confirmed for the systems involving ethane, methane, propane and ethylene using n-hexane and dodecane as solvents. This result shows agreement with the concept that diffusion is controlled by the molecular size of diffusing species. This work is presented in two parts; the first dealing with ethylene solubilities and the second dealing with ethylene diffusivities in selected solvents and two component solvent solutions.