Carbon Dioxide Solubilities and Diffusivities in 1-Alkyl-3-methylimidazolium Tricyanomethanide Ionic Liquids: An Experimental and Modeling Study

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• 作者：Lawien F. Zubeir ; Tim M. J. Nijssen ; Theodora Spyriouni ; Jan Meuldijk ; Jörg-Rüdiger Hill ; Maaike C. Kroon
• 刊名：Journal of Chemical & Engineering Data
• 出版年：2016
• 出版时间：December 8, 2016
• 年：2016
• 卷：61
• 期：12
• 页码：4281-4295
• 全文大小：862K
• ISSN：1520-5134

文摘

The solubility and diffusivity of CO₂ in a series of 1-alkyl-3methylimidazolium tricyanomethanide ionic liquids ([C_nmim][TCM] with n = 2, 4, 6, 7, 8; ILs) was studied using a magnetic suspension balance at temperatures ranging from 298 to 353 K and pressures up to 2 MPa. The effects of temperature, pressure, and alkyl chain length on CO₂ solubility and diffusivity were examined. The electrolyte PC-SAFT (ePC-SAFT) equation of state was used to describe the solubility of CO₂ in the ILs. The Henry’s law constant and the excess properties of solvation (Gibbs free energy, enthalpy, and entropy) were calculated. A series of equations derived from Fick’s second law were evaluated, and a Fourier expansion of Fick’s second law of diffusion was found to be the most suitable model for deriving diffusivities from gravimetric data. The diffusivities range from 10^–10 to 10^–9 m²·s^–1 in the temperature and pressure ranges applied. The activation energies for CO₂ diffusion (12–16 kJ·mol^–1) were found to be in the range of traditional solvents.