Liquid−Liquid Equilibrium in Mixtures of the Ionic Liquid 1-n-Butyl-3-methylimidazolium Hexafluorophosphate and an Alkanol

Abstract

The liquid-liquid phase equilibrium of mixtures of the room temperature ionic liquid 1-n-butyl-3-methylimidazolium hexafluorophosphate, [bmim][PF 6 ], and three single alkanols (ethanol, 1-propanol, and 1-butanol) was investigated over the entire composition range at ambient pressure. The experiments were conducted from 262 K to the vicinity of the critical solution temperature of the binary mixture (at maximum 362 K) by two different methods, namely, synthetic cloud-point measurements and analytical UV spectroscopy. The cloud-point method was mainly applied for the [bmim][PF 6 ]-rich liquid, whereas UV spectroscopy was used to determine the very small concentrations of [bmim][PF 6 ] in the alkanols, since under these conditions the cloud-point method is no longer applicable. All three systems show an upper critical solution temperature. With increasing chain length of the alcohol, that temperature rises and simultaneously the biphasic region becomes larger. Inspired by recent publications, the liquid-liquid equilibrium of these three binary systems was predicted by applying the COSMO-RS method. Calculations resulted in predictions of a miscibility gap, but the calculated miscibility gap strongly differs from the experimental results. A far better representation of the experimental data was accomplished via a UNIQUAC-based correlation.

Modeling ionic liquids and the solubility of gases in them: Recent advances and perspectives

“…RST [55][56][57], [59,60] [ COSMO-RS [125][126] [121], [125,126], [129] [ 125,126], [129] [118], [120][121][122][123][124][125][126][127][128][129][130] VLE and LLE of alcohols, hydrocarbons, ethers, ketones and water.…”

Quantum chemical studies on the simultaneous interaction of thiophene and pyridine with ionic liquid

“…The same authors evaluated and predicted the LLE and VLE of aqueous systems of ILs using COSMO-RS model. 35 Further, binary LLE system of IL with ethanol, 1-propanol, and 1-butanol were investigated over the whole molefraction of ionic liquid at ambient pressure by Sahandzhieva et al 36 COSMO-RS model have also been applied successfully for the screening of potential ionic liquid for the separation of 1-hexene and n-hexane 37 mixtures. LLE of ionic liquid (1-alkyl-3-methylimidazolium methylsulphate) with alcohols, ethers, and ketones have been predicted using COSMO-RS model by Domanska et al 38 They also predicted the binary LLE for the IL system namely 1,3-dimethylimidazolium or 1-butyl-3-methylimidazolium methylsulfate with hydrocarbons such as benzene, toluene, ethyl benzene, propylbenzene, o-xylene, m-xylene, and p-xylene at atmospheric pressure.…”

UNIQUAC correlation of liquid–liquid equilibrium in systems involving ionic liquids: The DFT–PCM approach

“…Due to lack of pure component volume and area parameters for ionic liquids, the UNIQUAC model [22] could not be widely used for correlating the experimental data. At the present time, only a few works [23][24][25][26][27][28][29][30][31] have tried to correlate LLE data for ternary systems including ionic liquids by the UNIQUAC model. Sahandzhieva et al [23] studied systems involving the ionic liquid [bmim][PF 6 ]; Banerjee et al [24] …”