The solubility of ethylene (H2C=CH2), propyne (CH3-C≡C-H), 2-methyl-2-butene (CH3-CH=C(CH3)2), and isoprene or 2-methyl-1, 3-butadiene (H2C=C(CH3)-CH=CH2) in liquid argon has been measured using mid-infrared and near-infrared (NIR) absorption. Spectra were recorded in the C-H infrared (IR) region. Spectra were obtained at increasing solution composition until the magnitude of the integrated absorption band reached a maximum value, indicating a saturated solution. The approximate experimental solubilities are: (600 ± 100) ppm at 92 K for ethylene, (22 ± 9) ppm at 100 K for propyne, (9 ± 5) ppm at 100 K for 2-methyl-2-butene, and (12 ± 2) ppm at 86 K for isoprene. The experimental solubility values at the corresponding temperature were used with solubility parameters of two separate models: the perturbed-chain statistical associating fluid theory (PC-SAFT) and the regular solution theory. Solvent-solute interaction parameters k12 (PC-SAFT) and [Formula: see text] (RST) were obtained for each solute in the presence of argon as the solvent. Data from experimental measurements are important for more realistic simulations of solubility of solids in cryogenic liquids.
Keywords: Solubility; cryogenic; infrared spectroscopy; liquid argon; unsaturated hydrocarbons.