Measurement and modeling of CO2 solubility in [bmim]Cl – [bmim][Tf2N] mixed-ionic liquids for design of versatile reaction solvents

Yuya Hiraga, Kento Koyama, Yoshiyuki Sato, Richard L. Smith

Research output: Contribution to journalArticlepeer-review

20 Citations (Scopus)


In this work, mixtures of 1-butyl-3-methylimidazolium chloride ([bmim]Cl) and 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([bmim][Tf2N]) were chosen to study because [bmim]Cl is suitable for processing biomass and [bmim][Tf2N] is suitable for increasing carbon dioxide (CO2) solubility in the ionic liquid phase. Solubilities of CO2 in mixed ionic liquid systems ([bmim]Cl and [bmim][Tf2N]) were measured at (353–393) K and at pressures up to 15 MPa with a magnetic suspension balance technique. Mixed ionic liquids were prepared at mole ratios, [bmim]Cl: [bmim][Tf2N] of 0.75: 0.25, 0.50: 0.50 and 0.25: 0.75. CO2 solubility in mixed ionic liquids changed regularly from that in single [bmim]Cl to that in single [bmim][Tf2N]. By assuming mixed ionic liquids as a mixture of two ionic liquids, the ε*-modified Sanchez-Lacombe equation of state could predict CO2 solubility data with pure component parameters of single ionic liquids and interaction parameters for [bmim]Cl-CO2, [bmim][Tf2N]-CO2 and [bmim]Cl-[bmim][Tf2N] to within an average relative deviation of 2.4%.

Original languageEnglish
Pages (from-to)42-50
Number of pages9
JournalJournal of Supercritical Fluids
Publication statusPublished - 2018 Feb


  • Equations of state
  • Functional ionic liquid mixtures
  • Gas solubility
  • Magnetic suspension balance
  • Physical properties

ASJC Scopus subject areas

  • Chemical Engineering(all)
  • Condensed Matter Physics
  • Physical and Theoretical Chemistry


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