Phase Behavior of N2O and CO2 in Room-Temperature Ionic Liquids [bmim][Tf2N], [bmim][BF4], [bmim][N(CN)2], [bmim][Ac], [eam][NO3], and [bmim][SCN]

Abstract

The gas solubility of nitrous oxide (N 2 O) in room-temperature ionic liquids, 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide, 1-butyl-3-methylimidazolium tetrafluoroborate, 1-butyl-3-methylimidazolium dicyanamide, 1-butyl-3-methylimidazolium acetate, 1-butyl-3-methylimidazolium thiocyanate, and ethylammonium nitrate has been measured at isothermal conditions from about (283 to 348) K using a gravimetric microbalance. The observed pressure-temperature composition (PTx) data have been analyzed by use of a generic Redlich-Kwong equationof-state (EOS) model, which has been successfully applied in our previous works. The interaction parameters have been determined using our measured vapor-liquid equilibrium data. Vapor-liquid-liquid equilibrium measurements have been made and validate EOS model predictions which suggest that these systems demonstrate Type III and Type V phase behavior, according to the classification of van Konynenburg and Scott. The global phase behavior of N 2 O has also been compared with both the measured data from this study and literature data for carbon dioxide (CO 2 ) in each ionic liquid and Henry's law constants are compared at room temperature (298.15 K).

Solubility of CO2 and N2O in an Imidazolium-Based Lipidic Ionic Liquid

“…Unlike in olive oil, the solubilities of CO 2 and N 2 O in many imidazolium-based ionic liquids are very similar, with N 2 O typically having a slightly higher solubility. ,,, The higher N 2 O solubility in many ionic liquids may be attributed to N 2 O having stronger interactions with the charged domains of the ionic liquid; although, we note that this would not be the cause of higher N 2 O than CO 2 solubility in lipids. The selective solubility of CO 2 over N 2 O can be significantly enhanced by using an acetate anion, which is known to interact with the Lewis acidic CO 2 .…”

“…In this work we employ a modified Redlich–Kwong (RK) cubic equation of state that has been used extensively by Shiflett and Yokozeki − ,, to model binary and ternary systems involving refrigerants and lubricants, as well as gases with ionic liquids. The model uses the standard construction of the RK equation with modified temperature-dependent term α and mixing rules shown below. For the liquid phase, which is comprised of both components, the mixing rules for the mixture values of a and b are given below, with binary interaction parameters l ij , l ji , τ ij , and m ij .…”

“…Because of this interest, the solubility of a wide range of gases has been studied in a broad variety of ionic liquids. − Much of the interest has focused on environmental applications such as the absorption of CO 2 , both physical and chemical, − from industrial process streams. The absorption of N 2 O (nitrous oxide), another volatile gas with negative environmental impact, in ILs, has also been the subject of a number studies. − N 2 O has two significant and deleterious effects on the environment: it is both a significant greenhouse gas, with a long atmospheric lifetime of over 100 years and a global warming potential almost 300 times that of CO 2 , and it is estimated to be the dominant ozone depleting gas of the 21st century . Nitrous oxide emissions arise from both biological and industrial origins, and industrial emission sources range from adipic acid production to its use as an anesthetic…”

Screening of Ionic Liquids and Deep Eutectic Solvents for Physical CO2 Absorption by Soft-SAFT Using Key Performance Indicators

“…It should be noted, that in most cases, the binary parameters were fixed to unity, with the CO 2 solubility in these solvents directly predicted from the molecular parameters of the pure fluids (see Table S3), reinforcing the robustness of the soft-SAFT model and the molecular parameters. The soft-SAFT computations for the solubility of CO 2 in ILs and DESs investigated in this work are depicted in Figure , validating the robustness of soft-SAFT, accurately capturing the trends for the experimental CO 2 solubility in ILs ,− and DESs, ,− respectively.…”

“…CO 2 solubility in the physical solvents studied in this work, for a variety of ILs depicted in (top), and DESs depicted in (bottom), modeled using binary interaction parameters shown in Table S3 in the Supporting Information. Soft-SAFT calculations (lines) compared to experimental data for CO 2 + ILs, ,− and for CO 2 + DESs ,− (symbols).…”