Physicochemical Properties of the Protic Ionic Liquid Bis(2-hydroxyethyl)methylammonium Formate

A protic ionic liquid, bis(2-hydroxyethyl)methylammonium formate, (BHEMF), was synthesized and characterized. The density and surface tension of the protic ionic liquid were determined in the temperature range of 293.15?C343.15?K. The molar volume and surface entropy were estimated from the experimental density and surface tension data, respectively. In terms of Glasser??s theory, the standard molar entropy and lattice energy of the protic ionic liquid were estimated. Using the methods of Kabo and Rebelo, the molar enthalpy vaporization of the protic ionic liquid, $ ^{l} \Updelta^{g}H_{\text{m}}^{0} $ (298.15?K) at 298.15?K and $ ^{l} \Updelta^{g}H_{\text{m}}^{0} $ (T _b), at the hypothetical normal boiling point were estimated, respectively. According to the interstical model, the thermal expansion coefficient of the protic ionic liquid, ??, was calculated and the result is in very good agreement with the experimental value.     

Density and Excess Molar Volume of the Protic Ionic Liquid Bis(2-hydroxyethyl)ammonium Acetate with Alcohols

Densities were determined for binary mixtures containing the protic ionic liquid bis(2-hydroxyethyl)ammonium acetate [BHEAA] and an alcohol (methanol, ethanol, and 1-propanol) at four different temperatures (293.15, 303.15, 313.15, and 323.15) K and ambient pressure. Coefficients of thermal expansion and excess molar volumes were calculated from the experimental densities. The excess molar volumes were fitted using the Redlich-Kister polynomial equation. Negative deviations from ideal behavior of the excess molar volume were observed for all systems investigated in this study. The results were interpreted in terms of ion-dipole interactions and structural factors of the ionic liquid and alcohol. It was observed that an increase of the alcohol carbon chain length led to lower interactions on mixing.     

Molecular-Microscopic Properties and Preferential Solvation in Protic Ionic Liquid Mixtures

Structural and molecular-microscopic properties of the solvatochromic probes 4-nitroaniline, 4-nitroanisole, and Reichardt’s dye were investigated in binary mixtures of ethylammonium propionate with methanol, ethanol, 1-propanol and 2-propanol. Solvatochromic parameters (α, hydrogen-bond donor acidity; β, hydrogen-bond acceptor basicity; π*, dipolarity/polarizability; $ E_{\text{T}}^{\text{N}} $ , normalized polarity parameter) in different binary mixtures of ionic liquid with molecular solvents were determined with UV–Vis spectroscopy. The $ E_{\text{T}}^{\text{N}} $ parameters show nearly ideal trends in all solvent mixtures, but the other parameters show different behavior in the mixtures. The π* parameters show a negative deviation from ideality in the ionic liquid/methanol system. In contrast, the α parameters have severe positive deviations from ideal behavior in ionic liquid/1-propanol and ionic liquid/2-propanol solvent mixtures. A synergistic solvation effect is observed for the π* parameters in IL/methanol mixtures. Specific solute–solvent interactions or solvent–solvent interactions, which cause non-ideal trends in some parameters, are justified and interpreted by the preferential solvation model.     

2-Metoxyethanol-Acetonitrile Binary Mixtures and Their Physicochemical Properties

Abstract

Densities (d ₁₂) and relative permittivities (\Varepsilon₁₂) have been measured for 2-metoxyethanol (ME) and acetonitrile (ACN) binary liquid mixtures over their whole compositions ranges at various temperatures ranging from 288.15K to 308.15K. The experimental data were used to test some empirical equations of the type: y ₁₂=y ₁₂(t) and y ₁₂=y ₁₂(X ₁) (where: y ₁₂-d ₁₂ or \Varepsilon₁₂). From all these data, the excess molar volumes (V ^E _m), temperature coefficients of relative permittivities (α₁₂) and the excess extrathernmodynamic parameters \Varepsilon^E were calculated. The ¹H-NMR spectra of liquid binary mixtures of ME and ACN, were recorded at 298 K over almost the whole range of the mixed solvent compositions. From these data the values of the values of the spectral structural parameters were found, Δδ(ME-ACN). The values of these structural parameters are discussed in terms of interactions of 2-metoxyethanol with acetonitrile.     

Volumetric Properties of Binary Mixtures of the Ionic Liquid 1-Butyl-3-Methylimidazolium Tetrafluoroborate with Aniline

The densities of binary mixtures of an ionic liquid 1-butyl-3-methylimidazolium tetrafluoroborate, [bmim][BF₄], with an aromatic compound, aniline, have been determined over the full range of compositions and over the temperature range 298.15 to 313.15 K at atmospheric pressure using a vibrating-tube densimeter (DMA4500). Excess molar volumes ( V_m^EV_{\mathrm{m}}^{\mathrm{E}} ) have been obtained from these experimental results, and were fitted by the fourth-order Redlich–Kister equation. In addition, partial molar volumes, apparent molar volumes and partial molar volumes at infinite dilution have been calculated for each component. Our results show that values of V_m^EV_{\mathrm{m}}^{\mathrm{E}} decrease slightly when the temperature increases in this system. The results have been interpreted in terms of ion-dipole interactions and structural factors of the ionic liquid and the organic molecular liquid.     

Measurement and Calculation the Excess Molar Properties of Binary Mixtures Containing Isobutanol, 1-Amino-2-Propanol,and 1-Propanol at Temperatures of (293.15 to 333.15) K

Densities, ρ, and viscosities, η, of pure isobutanol, 1-amino-2-propanol, and 1-propanol, along with their binary mixtures of {x ₁isobutanol + x ₂1-propanol}, {x ₁1-amino-2-propanol + x ₂1-propanol}, and {x ₁1-amino-2-propanol + x ₂isobutanol} were measured over the entire composition range and at temperatures (293.15–333.15) K at ambient pressure (81.5 kPa). Excess molar properties such as the excess molar volume, V _m ^E , partial molar volumes, \( \bar{V}_{1} \) and \( \bar{V}_{2} \), excess partial molar volumes, \( \bar{V}_{1}^{\text{E}} \) and \( \bar{V}_{2}^{\text{E}} \), thermal expansion coefficient, α, excess thermal expansion coefficient, α ^E, viscosity deviation, Δη, and the excess Gibbs energy of activation, ?G ^E*, for the binary mixtures were calculated from the experimental values of densities and viscosities. The excess values of the binary mixtures are negative in the entire composition range and at all temperatures, and increase with increasing temperature. Viscosity deviations, Δη, are negative over the entire composition range and decrease with increasing temperature. The viscosities of the mixtures were correlated by the models of McAllister, Heric, Hind, Katti, and Nissan. The obtained data were correlated by Redlich–Kister equation and the fitting parameters and standard deviations were determined.     

Osmotic and Activity Coefficients of Nonaqueous Electrolyte Solutions. 1. Lithium Perchlorate in the Protic Solvents Methanol, Ethanol, and 2-Propanol

Vapor pressure lowering by the addition of LiClO₄ to the protic solvents methanol (0.04–5.1 m), ethanol (0.03–1.5 m), and 2-propanol (0.05–1.5 m) was measured at 25°C with high precision. The experimental data of the corresponding osmotic coefficients are compared to those obtained by the use of Pitzer equations and chemical model calculations. Mean activity coefficients are derived from the osmotic coefficients.     

Solubility and Thermodynamic Properties of (1R,2R)-(+)-1,2-Diaminocyclohexane L-Tartrate in Methanol (Ethanol or 2-Propanol) + Water Binary Solvents at Various Temperatures

Russian Journal of Physical Chemistry A - The solubility of (1R,2R)-(+)-1,2-diaminocyclohexane L-tartrate (DHT) in methanol + water, ethanol + water, and 2-propanol + water mixed solvents were...     

Surface Tension of Binary Mixtures of 1-Alkyl-3-Methyl-Imidazolium Bis(trifluoromethylsulfonyl)imide Ionic Liquids with Alcohols

New experimental surface tension data have been provided at 283.15, 298.15, 313.15 K and atmospheric pressure for binary mixtures of 1-butyl-3-methyl-imidazolium bis(trifluoromethylsulfonyl)imide and 1-octyl-3-methyl-imidazolium bis(trifluoromethylsulfonyl)imide ionic liquids with the alcohols: methanol, ethanol, 1-propanol, 2-propanol, l-butanol and 1-pentanol. The experimental results show that the surface tensions of these mixtures depend systematically on the alkyl chain length of the ionic liquid and alcohol, composition and temperature. Surface tension changes on mixing have been calculated and adequately fitted by the Redlich–Kister polynomial equation. The adjustable parameters and the standard deviations between experimental and calculated values are reported.     

Derived Properties of Binary Mixtures Containing (Acetone or Methanol) + Hydroxil Compounds

Abstract

This work reports values of the density, refractive index and speed of sound of the binary mixtures acetone or methanol with (2-methyl, 1-propanol, 3-methyl, 1-butanol, 1,2-ethanediol, 1,2-propanediol and 1,3-propanediol) at 298.15 K and atmosphere, as a function of the mole fraction. From the experimental values, the corresponding excess and derived magnitudes were computed (excess molar volumes, changes of refractive index on mixing and changes of isentropic compressibility on mixing), variable-degree polynomials being fitted to the results. Only expansive trend was observed for those mixtures enclosing branched alcohols. The influence of the hydroxil group in the nonideal behaviour of these mixtures were analyzed in terms of the partial molar excess volumes.     

Binary Mixtures of Aprotic and Protic Ionic Liquids Demonstrate Synergistic Polarity Effect: An Unusual Observation

In this communication, we demonstrate the solute–solvent and solvent–solvent interactions in the binary mixtures of two aprotic ionic liquids, namely 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide and 1-butyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide, with the protic ionic liquid 1-methylimidazolium acetate. The synergistic effects as expressed by the solvatochromic parameter are noted. This observation is in contrast to the mixing of protic ionic liquids 1-methylpyrrolidium acetate and 4-methylmorpholine acetate with 1-methylimidazolium acetate, respectively. It appears that the synergistic effects in the binary mixtures of aprotic and protic ionic liquids are caused by the formation of hydrogen bonds, since cations are dominant H-bond donors while anions are dominant H-bond acceptors. Preferential solvation models are used to describe the solute–solvent interactions in the binary ionic liquid mixtures.     

Acetonitrile - 2-Methyl-Propan-1-ol and Acetonitrile - 2-Methyl-Propan-2-ol Binary Mixtures and their Physicochemical Properties

The 1 H-NMR spectra of liquid binary mixtures of acetonitrile with 2-methyl-propan-1-ol (i-BtOH) and 2-methyl-propan-2-ol (t-BtOH), were recorded at 298 K over almost the whole range of mixed solvent compositions. From these data the values of spectral parameters, j i (ACN-i-BtOH) and j i (ACN-t-BtOH) were found. The relative permittivities ( k 12 ) and the densities ( d 12 ) of the mixed solvents were measured at 288.15 K, 293.15 K, 298.15 K, 303.15 K and 308.15 K. The experimental data were used to test some empirical equations of the type: y 12 = y 12 ( t ) and y 12 = y 12 ( X 1 ) [where: y 12 = d 12 or k 12 ]. From all these data, the deviations from ideality molar volumes , temperature coefficients of relative permittivities ( f 12 ) and the excess extrathermodynamic parameters were calculated. The values of these structural parameters are discussed in terms of interactions of acetonitrile with both alcohols.     

Physical and Excess Properties for Binary Mixtures of 1-Methyl-3-Octylimidazolium Tetrafluoroborate, [Omim][BF4], Ionic Liquid with Different Alcohols

In recent years, ionic liquids have increasingly gained importance as green solvents. The potential of these organic salts, which are moisture and air stable at room temperature, for new chemical processes and technologies is beginning to be recognized. Research on the thermophysical properties of ionic liquids and their mixtures form the basis for future applications. In this contribution, densities, refractive indices, speeds of sound and dynamic viscosities of 1-methyl-3-octylimidazolium tetrafluoroborate, [Omim][BF₄], the room temperature ionic liquid (IL) in binary mixtures with methanol, ethanol, 1-propanol and 2-propanol were measured at 298.15K and atmospheric pressure. The excess molar volumes and molar refraction, isentropic compressibility and dynamic viscosity changes of mixing have been calculated and were satisfactorily correlated by the Redlich–Kister polynomial.     

Measurement and Correlation Solubility of Sodium Succinate in Binary Mixed Solvents of Water + (Methanol or Ethanol) Mixtures

The solubility of sodium succinate in binary solvent mixtures was measured by an analytical stirred-flask method in the temperature range 278.15–318.15 K at atmospheric pressure. It was found that the solubility of sodium succinate in the system increased with increasing temperature and decreased with the increasing mass fractions of methanol or ethanol. The modified Apelblat equation, the Buchwski–Ksiazaczak λh equation and the combined nearly ideal binary solvent/Redlich–Kister (CNIBS/R–K) equation were proposed for correlating the experimental data. The modified Apelblat equation was found to regress the solubility data much better than the Buchwski–Ksiazaczak equation and the CNIBS/R–K equation in a binary solvent system. The dissolution enthalpy and dissolution entropy of sodium succinate were calculated from the solubility data, using the Van’t Hoff equation. The experiment results and correlation models could be used as essential data in the purification of sodium succinate.     

An Infrared Investigation of Hydrogen Bonding of Methanol,Ethanol, 1-Propanol,and 1-Butanol in Solution

The aggregation phenomena of simple alcohols caused by hydrogen bonding in several organic solvents are studied by I. R. spectroscopy. The association constants of cyclic dimer of alcohols in CCI₄ are evaluated, and the importance of solvent bascity effecting on the OH band frequency shift has been discussed.     

Physicochemical Properties of Acetonitrile-Butan-1-Ol and Acetonitrile-Butan-2-Ol Mixtures

Abstract

The densities (d₁₂ ) and relative permittivities (?¹²) of liquid binary mixtures of acetonitrile-butan-l-ol and acetonitrile-butan-2-ol were measured at 288.15 K, 293.15 K, 298.15 K, 303.15 K and 308.15 K, as well as refractive indices (n ^D ₁₂) at 298.15 K and surface tensions (σ₁₂) at 293.15 K, 298.15 K and 303.15 K. From all these data, the molar volumes (V _m ), apparent molar volumes (V _{i, φ}), temperature coefficients of relative permittivities (α₁₂) and surface tensions (k) and their deviations from ideality were calculated. Additionally, the Kirkwood's correlation factors (g _K ) were found. The values of these properties are discussed in terms of interactions of acetonitrile with butan-1-ol and butan-2-ol.     

Thermochemical Properties of the 1-Ethyl-3-Methylimidazolium Bis(trifluoromethylsulfonyl)imide Ionic Liquid under Conditions of Equilibrium with Atmospheric Moisture

Thermochemical properties of the 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl) imide ionic liquid [EMim]NTf₂ containing moisture absorbed from the atmosphere (0.242 wt %) are investigated. The phase behavior and thermal stability relative to salt dried in vacuum are studied by means of thermogravimetry and differential scanning calorimetry at different heating and cooling rates. The glass transition, crystallization, and melting temperatures, the enthalpies of phase transitions, and the changes in heat capacity during the formation of glass are determined. It is established that the absorbed water crystallizes at a temperature of around ?40.6°C and has virtually no effect on the thermal stability and phase behavior of the salt. Rapid cooling results in the ionic liquid transitioning into the glass state at ?91.7 °C and the formation of three mesophases with different melting temperatures; one crystalline modification that melts at a temperature of ?19.3°C forms upon slow cooling.     

Temperature Dependence of Changes of Refractive Index in Methyl Acetate,Ethanol and 2-Propanol Mixtures

Abstract

The refractive indices of the mixtures methyl acetate+ethanol+2-propanol, methyl acetate+ethanol and methyl acetate+2-propanol have been determined experimentally as a function of composition at the temperature range 288.15–308.15K and atmosphere. Parameters of polynomial equations which represent the composition and temperature dependence of the corresponding derived magnitude are gathered. The applicability of semiempirical equations is analyzed in order to estimate the ternary changes of refractive indices on mixing at these temperatures by means of only binary derived values.     

Solvatochromic Probes Absorbance Behavior in Mixtures of 2-Hydroxy Ethylammonium Formate with Methanol,Ethylene Glycol and Glycerol

Solute-solvent and solvent-solvent interactions were investigated for binary mixtures of an ionic liquid (IL) 2-hydroxy ethylammonium formate as with methanol, ethylene glycol and glycerol. The physicochemical properties of the solvent mixtures at 25 °C, over the whole range of mole fractions, were determined using solvatochromic probes. High normal polarity (E_T^NE_{T}^{N}) in the alcohol-rich region confirms solute-solvent interactions in this medium. Dipolarity/polarizability (π ^∗) show a different trend to E_T^NE_{T}^{N} with a positive deviation from ideal behavior in IL-glycerol mixtures. However, these deviations for other solvent mixtures are insignificant. Contrary to what is observed for E_T^NE_{T}^{N} and π ^∗, hydrogen-bond donor (HBD) acidity and hydrogen-bond acceptor (HBA) basicity demonstrate similar trends. The applicability of the combined nearly-ideal binary solvent/Redlich-Kister (CNIBS/R-K) equation for the correlation of various parameters provides a simple computational model to correlate and/or predict various solvatochromic parameters for many binary solvent systems.