New Experimental Data on Thermodynamic Properties of the Aqueous Solution of N,N-Diethyl-N-methylammonium Bromide and N,N-Diethyl-N-methylammonium Methanesulfonate

Abstract

In this work, new experimental data on thermodynamic properties of ionic liquid (IL) aqueous solutions are presented. The (vapor + liquid) phase equilibria, liquid density, and dynamic viscosity of binary mixtures composed of N,N-diethyl-N-methylammonium bromide ([NH,1,2,2]­[Br]), or N,N-diethyl-N-methylammonium methanesulfonate ([NH,1,2,2]­[CH3SO3]) and water are presented as functions of temperature and composition. Both ILs were synthesized and specific basic characterization including the NMR spectra and the water content determination was done. The basic thermal properties of the pure IL, including the glass-transition temperature, heat capacity at glass transition, and temperature and enthalpy of (solid + solid) phase transition as well as the temperature and enthalpy of melting were determined using the differential scanning calorimetry (DSC) technique. The isothermal (vapor + liquid) equilibrium (VLE) was measured by the ebulliometric method within a temperature range from T = 338.15 to 368.15 K and pressures up to 85 kPa. Experimental VLE data were successfully correlated using the NRTL equation. The experimental VLE data were tested for thermodynamic consistency using the Van Ness test. The liquid density and the dynamic viscosity were determined as a function of IL’s mole fraction over a wide temperature range. For the correlation of physicochemical properties, empirical equations were applied. From the experimental density data, the excess molar volumes were determined and correlated using the Redlich–Kister-type equation.

Thermal Decomposition, Low Temperature Phase Transitions and Vapor Pressure of Less Common Ionic Liquids Based on the Bis(trifuoromethanesulfonyl)imide Anion

“…For the presently investigated ionic liquids, it varies from 136 ± 18 kJ/mol for m-C 6 H 4 (CH 2 ImMe)][NTf 2 ] 2 to 147 ± 12 and 147 ± 13 kJ/mol for [DABCO10][NTf 2 ] and [p-C 6 H 4 (CH 2 ImBu)][NTf 2 ] 2 , respectively, and finally to 180 ± 17 kJ/mol for [C 6 Py][NTf 2 ]. These values are consistent with those previously reported for the other ionic liquids [ 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 , 31 , 32 , 33 , 34 , 35 ].…”

“…The fluorinated FSI anion was reported to significantly decrease [ 23 ] or increase [ 24 ] the vapor pressure compared to NTf 2 . ILs containing the diethyl phosphate [ 25 ], thiocyanate [ 26 ], methanesulfonate [ 27 ], formate and acetate [ 28 ] anions displayed high values of the vapor pressure, while those based on the iodide, bromide or chlorine anions have extremely low values of p v [ 29 , 30 ]. ILs containing the B(CN) 4 anion have p v comparable to that of NTf 2 samples [ 31 ].…”

Temperature and Composition Dependence of the Thermodynamic Properties of an Aqueous Solution of 1-Ethyl-3-methylimidazolium Formate and 1-Ethyl-3-methylimidazolium Acetate

“…The thermometer and the manometer were calibrated by measuring the boiling points as a function of pressure for n -octane, water, and ethanol compared to values obtained from the literature . The experimental boiling temperature versus pressure used for calibration are collected in Table S1 and graphically presented in Figure S1 in the Supporting Information. For ethanol, our previous data was used for calibration . The uncertainty was at the level of u ( p ) = 0.2 kPa and u ( T ) = 0.01 K. In this experiment, the vapor pressure as a function of the IL mole fraction in the liquid phase is reported at a constant temperature.…”

“…For ethanol, our previous data was used for calibration. 47 The uncertainty was at the level of u(p) = 0.2 kPa and u(T) = 0.01 K. In this experiment, the vapor pressure as a function of the IL mole fraction in the liquid phase is reported at a constant temperature. Due to the extremely low volatility of the IL, the vapor phase is composed only of solvent in the studied system.…”

“…To compare the effect of IL’s anion structure, the thermodynamic properties of an aqueous IL solution with a shorter alkyl chain ([EMIM]­[HCOO]) are presented in this work. This paper is a continuation of our systematic research on the possibility of applying an aqueous solution of IL in absorption refrigeration technology. − In this work, we present the thermophysical properties of pure ILs and the thermodynamic properties including VLE and liquid density for an aqueous solution of two ILs: 1-ethyl-3-methylimidazolium formate ([EMIM]­[HCOO]) and 1-ethyl-3-methylimidazolium acetate ([EMIM]­[CH3COO]). The experimental VLE data for the [EMIM]­[CH 3 COO] aqueous solution has been compared to those presented by Römich et al .…”