Nuclear magnetic resonance spectroscopic studies of the trihexyl (tetradecyl) phosphonium chloride ionic liquid mixtures with water

Abstract

Tetra-alkyl Phosphonium ionic liquids are phosphonium salts with melting points near room temperature. We report the NMR studies of water-trihexyl (tetradecyl) phosphonium chloride ionic liquid mixtures. The proton chemical shifts were used to investigate the intermolecular interactions in mixtures of ionic liquids and water. The OH chemical shifts were found to decrease as the water concentration in the ionic liquid increased, and their rate of change with temperature decreased with water concentration. The CH 2 and CH 3 chemical shifts were found to move downfield with the increase in temperature, and moved further downfield as water concentration was decreased. The interface of experimental data and the results of quantum calculations suggest a significant binding of phosphonium cations to chloride anion and water molecules. As well, the analysis of the data suggests a possible transformation from cationchloride-water configuration at low water concentrations to cation-water-water at higher water concentrations.© Versita Warsaw and Springer-Verlag Berlin Heidelberg.

Multiscale modeling of the trihexyltetradecylphosphonium chloride ionic liquid

“…7 presents the site-site Cl-HP RDFs calculated from atomistic and coarse-grained simulations at 293, 333, and 393 K, respectively. A sharp and intense peak registered at approximately 0.25 nm contributes to the formation of hydrogen bonds between the HP atoms in [P 6,6,6,14 ] cations and the Cl anionic groups, which is consistent with previous experimental NMR spectroscopic studies [78][79][80][81] and the electronic structure calculation 9,35,78 of the [P 6,6,6,14 ]-based ILs. The three secondary peaks characterized with less peak intensities are observed at larger distances.…”

“…This observation is similar to the spatial distributions of chelated orthoborate anions and water molecules around tetraalkylphosphonium cations reported in our previous studies. A sharp and intense peak registered at approximately 0.25 nm contributes to the formation of hydrogen bonds between the HP atoms in [P 6,6,6,14 ] cations and the Cl anionic groups, which is consistent with previous experimental NMR spectroscopic studies [78][79][80][81] and the electronic structure calculation 9,35,78 of the [P 6,6,6,14 ]-based ILs. 35,37,[56][57][58] Fig.…”

Performance of dispersion-corrected density functional theory for the interactions in ionic liquids

“…However, recently they gain more attention for example for reasons of phase separation processes. 99,100 Force fields have been developed in the Canongia Lopes and Pa´dua series. 101 Electronic structure calculations of [P 6,6,6,14 ][Cl] have been conducted and ion association energies of À81.6 kcal mol À1 were found at the B3LYP/6-311++G** level of theory.…”

Microemulsion-like aggregation behaviour of an LCST-type ionic liquid in water

“…Ghandi and coworkers have used proton chemical shis to investigate the intermolecular interactions in mixtures of trihexyl(tetradecyl)phosphonium chloride IL and water. 40 The chemical shis of protons on alkyl chains were also found to move downeld as the temperature was increased, as well as when the water concentration in the IL was decreased. However, the temperature coefficient was found to be very much smaller at high water concentrations, which means that the effect of temperature on the chemical shi of can be ignored.…”