Solubility of the single gases methane and xenon in the ionic liquid [hmim] [Tf2N]

This work reports new experimental results for the solubility of two single gases (methane and xenon) in the ionic liquid 1-hexyl-3-methylimidazolium bis(trifluoromethylsulfonyl)amide ([hmim][Tf2N]). The solubility was measured with a high-pressure view-cell technique operating on the synthetic method. The temperature ranged from 293.3 to 413.3 K, and the maximum pressure (the maximum gas molality) was 9.3 MPa (0.51 mol center dot kg(-1)) for methane and 9.6 MPa (2.08 mol center dot kg(-1)) for xenon. Xenon shows a significantly higher solubility than methane at all conditions investigated. Both gases become less soluble in [hmim][Tf2N] with rising temperature. An extension of Henry's law is employed to correlate the solubility pressures. The final results for the Henry's constants (at zero pressure) of methane and xenon in [hmim][Tf2N] (on the molality scale) are represented within the experimental uncertainty (about 1.2% for methane and 1% for xenon) by ln(k(H,CH4)((0))/MPa) = 6.4929 - 835.9/(T/K) - 0.003471(T/K) and ln(k(H,Xe)((0))/MPa) = 6.3357 - 1321.4/(T/K) - 0.00265(T/K), respectively.