Activity Coefficients at Infinite Dilution of Organic Solutes in the Ionic Liquid 1-Ethyl-3-methyl-imidazolium Nitrate

Abstract

Infinite dilution activity coefficients gamma(1)(infinity) and gas-liquid partition coefficients K(L) of 30 selected hydrocarbons, alcohols, ketones, ethers, esters, haloalkanes, nitrogen- and sulfur-containing compounds in the ionic liquid (IL) 1-ethyl-3-methylimidazolium nitrate [EMIM][NO(3)] were determined by gas-liquid chromatography at five temperatures in the range from 318.15 to 353.15 K. Relative contribution of adsorption at gas-liquid interphase to the overall solute retention, as examined by varying sample size and IL loading in the column, was found negligible. Partial molar excess enthalpies and entropies at infinite dilution were derived from the temperature dependence of the gamma(1)(infinity) values. The linear free energy relationship (LFER) solvation model was used to correlate successfully the KL values. The LFER correlation parameters and excess thermodynamic functions were analyzed to disclose molecular interactions operating between the IL and the individual solutes. In addition, the promising potential of [EMIM][NO(3)] for applications in solvent-aided separation processes was identified, the selectivities of [EMIM][NO(3)] for separation of aromatic hydrocarbons and thiophene from saturated hydrocarbons ranking among the highest ever observed with ILs or molecular solvents.

Interactions of volatile organic compounds with the ionic liquids 1-butyl-1-methylpyrrolidinium tetracyanoborate and 1-butyl-1-methylpyrrolidinium bis(oxalato)borate

“…To determine the IL loading k of the solid support we used the gravimetric procedure based on backextraction of the IL from the coated supporting material. The procedure has been described in detail previously [10]. At least two separate samples of the coated support from each batch were examined.…”

“…The c term is the model constant. The Abraham's solute descriptors are available for a large number of compounds [27,34] and for those studied in this work were listed in Supporting Information to reference [10]. The system constants can be calculated from experimental K L values for a set of solutes using standard procedures of multiple regression analysis.…”

Activity coefficients at infinite dilution measurements for organic solutes and water in the ionic liquid 1-ethyl-3-methylimidazolium tetracyanoborate

“…The chief parameters in designing an effective extraction process are the selectivity, S 1 12 , and the capacity, k Table 4 summarizes the values of selectivity at infinite dilution for ILs based on different ions containing the cyano group and/or the [EMIM] + cation for n-hexane/benzene, cyclohexane/benzene, and n-heptane/thiophene separations [2][3][4][5]7,9,[21][22][23][24][25][26].…”

Activity coefficients at infinite dilution of organic solutes in 1-octyl-3-methylimidazolium nitrate using gas–liquid chromatography

“…From Table 8 it can be seen that the ionic liquid can be used Table 11 Influence of saturation vapor pressure (P 0 i ) on activity coefficients at infinite dilution of heptane, benzene, toluene, and o-xylene in the ionic liquid 1-octyl-3-methylimidazolium nitrate at 323. 15 for the benzene or toluene/alkane separations. However, the separation ability of this ionic liquid is smaller than the experimental selectivities of sulfolane [21,22].…”

“…Information on v i , ı i and r i were obtained from the literature[19]. The van der Waals volume of the IL was calculated by group contribution method[20].The linear dependence between Y i and ı i at 303 15. K obtained from the ∞ i,3 data for [OMIM][NO 3 ] was displayed in Fig.…”