Molar Isobaric Expansion Research Articles

Comparison of Solution Behaviors of Two Structurally Related Ionic Liquids in Water and in Acetonitrile as Studied by Volumetric and Acoustic Properties

Interactions of 1-butyl-1-methylpyrrolidinium tetrafluoroborate (BMPYBF4) and 1-butyl-1-methylpiperidinium tetrafluoroborate (BMPIBF4) with water and acetonitrile (AN) were studied in a comparative manner through the measurements of density and speed of sound at 288.15, 293.15, 298.15, 303.15 and 308.15 K. The measured densities and speeds of sound were used in calculation of apparent molar volumes and apparent molar isentropic compressions of the two ionic liquids (ILs) in water and in AN. Infinite dilution values of the two apparent molar quantities were obtained by extrapolation. Then, these properties were evaluated in terms of IL–water and IL–AN interactions. The effect of presence of an additional cyclic –CH2– group in the structure of BMPIBF4, compared to that of BMPYBF4, on the volumetric and acoustic properties has been examined both in water and in AN. The effect of solvent, H2O or AN, on the solution behaviors of the two ILs is discussed, based on transfer apparent molar volumes and transfer apparent molar isentropic compressions from H2O to AN. Apparent molar isobaric expansions at infinite dilutions were determined. Temperature effects on solution behaviors of the two ILs in H2O and in AN are discussed based on variation of apparent molar properties at infinite dilution with temperature.

Equimolecular cocrystal of cis- and trans-coordinated N,N′-dimethylglycolurils: Some standard thermodynamic properties in the aqueous solution between 278.15 K and 318.15 K

In this paper, we have discussed the results of densimetric and calorimetric studies of dissolution process in water for the (1:1) cocrystal consisting of two heterocyclic isomers being cis- and trans-coordinated dimethylglycolurils (2,8-DMGU and 2,6-DMGU, respectively) in the temperature range from (278.15 to 318.15) K at the ambient pressure. The standard (apparent or partial at infinite dilution) molar volumes and isobaric expansibilities of cocrystal as a solute in water were derived from the experimental data on solution density. Using thermochemical measurements, the standard molar enthalpies and isobaric heat capacities of the dissolution of cocrystal in water were also determined at the temperatures of interest. Based on the previously obtained similar results for aqueous 2,6-DMGU and 2,8-DMGU, a comparative analysis of packing and interaction changes in the hydration complex induced by the cocrystallization process has been carried out. It was found that the formation of cocrystal leads to a peculiar “synergism” in both volume and heat capacity effect of N,N′-dimethylglycoluril hydration at all temperatures studied.

Compatibility of sustainable solvents ionic liquid, 1-ethyl-3-methylimidazolium ethyl sulfate in some choline chloride based deep eutectic solvents: thermodynamics study

Nowadays, green neteric solvents are replaced the conventional organic solvents. In this regard, deep eutectic solvents (DESs) have evolved as neoteric solvents similar to ionic liquids (ILs) with various applications in different fields. This paper reports the density, and speed of sound data of the ionic liquid, 1-ethyl-3-methylimidazolium ethyl sulfate [EMIM][ES] in the some DESs, choline chloride/urea, choline chloride/ethylene glycol, choline chloride/glycerol and choline chloride/oxalic acid in dilute region concentration of the IL at temperature ranges T = (298.15 to 318.15) K and at atmospheric pressure. On the basis of these data, the apparent molar volume Vφ and apparent molar isentropic compressibility κφ were calculated. From these quantities and with help of Redlich-Mayer equation, the standard partial molar volumes and partial molar isentropic compressibility were obtained. The structure making or breaking behaviour of the [EMIM][ES] in the DESs studied has been described with the help of standard partial molar isobaric expansions Eφ0 and Hepler constant. The obtained parameters show that solute-solvent interactions between the IL and the DES are stronger for the choline chloride/urea solutions than the other investigated DESs. Finally, the Pitzer model have been used to correlate the values of Vφ and κφ, which indicates the Pitzer model has a good compatibility than the other models.

The (p-Vm-T-x) properties of {water (1) + acetamide (2)} mixtures in the range 278.15–323.15 K and 0.10–100 MPa

The density ρ at atmospheric pressure and compression ratios k=ΔV/Vo of the {water (1) + acetamide (2)} mixture in the range of temperature from 278.15 K to 323.15 K (278.15, 288.15, 298.15, 308.15, 323.15), pressures from 10 to 100 MPa (10, 25, 50, 75 and 100) and in a wide range of compositions (maximum mole fraction of acetamide (AA) x2 = 0.3875) were measured in the work. The partial molar volumes of both components V¯1 and V¯2 in the mixture, molar isothermal compression KT,m, molar isobaric thermal expansion EP,m, isochoric coefficient of thermal pressure βV, and internal pressure of the mixture Pint were calculated. The volume characteristics for an infinitely dilute AA solution in water: limiting partial molar volumes V¯2∞, limiting partial molar isothermal compression K¯T,2∞, and limiting partial molar isobar expansion E¯P,2∞ were calculated. The obtained results are discussed from the standpoint of interactions of solute-solvent and solute-solute. The obtained results are discussed in terms of solute-solvent and solute-solute interactions.

Thermodynamic and solution properties of sodium valporate in aqueous solution and its interaction with cetyl trimethylammonium bromide (CTAB)

This manuscript reports the volumetric, viscometric and aggregation properties of sodium valporate in aqueous solution. The interaction of drug with cationic surfactant (CTAB) was also studied. From volumetric study, partial molar volume, Hepler's constant, partial molar expansivity and isobaric thermal expansion coefficient were calculated while from viscometric study, the constants of Jones-Dole equation and thermodynamic parameters of viscous flow like free energy change, entropy change and enthalpy change were calculated. Critical micelle concentration of drug at four different temperatures was measured by surface tension and electrical conductivity measurements. The data was used to calculate surface excess concentration and thermodynamic parameters for the micellization process i.e. free energy of adsorption, free energy, entropy and enthalpy of micellization. Spectroscopic study of the drug/surfactant interaction was helpful to calculate partition coefficient, free energy of partition, binding constant and free energy of binding.

Volume-related solvation and pair interaction parameters for dilute solutions of urea and tetramethylurea in ethylene glycol between 288.15 K and 328.15 K: A comparative analysis

The densities of urea (U) and tetramethylurea (TMU) solutions in ethylene glycol (EG) at the solute molality range up to 1.5 mol·kg−1 were measured with the uncertainty of 0.03 kg·m−3 at T = (288.15, 298.15, 308.15, 318.15 and 328.15) K and p = 99.6 kPa using a vibrating-tube densimeter. The standard partial molar volumes and isobaric expansibilities as well as parameters of the solvent-induced solute–solute pair interactions for both ureas were calculated. The results were discussed in terms of hydrophilic and hydrophobic nature of U and TMU, respectively, and also on the background of the suggestion that EG, like liquid water, forms the hydrogen bond spatial network.

Volumetric and sound speed study of aqueous 1-butanol liquid mixtures at different temperatures

Simultaneous measurements of density and sound speed, at five temperatures, T = (283.15–303.15) K and pressure, P = 0.1 MPa within the miscible composition range were performed in 24 aqueous liquid mixtures of 1-butanol. Composition and temperature effects on different excess molar, and excess partial molar properties such as volume, isobaric expansion and isentropic compression are analysed, in terms of different changes in the hydration and association patterns, across the composition ranges studied. Comparison of the different thermodynamic properties, derived for this system, with those for two aqueous system of smaller number of carbon atoms is made. Limiting excess partial molar volumes, isobaric expansions and isentropic compressions at both ends of the composition range are presented. Limiting partial molar isentropic compression values for 1-butanol, infinitely diluted in water, compare very well with values calculated by the group contribution scheme previously presented by some of us.

Volumetric properties of the water + tetramethylurea mixture over the temperature range from 274.15 to 333.15 K at atmospheric pressure

The densities of the binary mixture {water (1) + tetramethylurea (2)} have been measured in the entire composition range in the temperature range from 274.15 K to 333.15 K at atmosphere pressure. Excess molar volumes and molar isobaric thermal expansions of the mixture, apparent and partial molar volumes, partial molar isobaric expansions of water and tetramethylurea (TMU), including their limiting values, are calculated. It is shown that the formation of the water + tetramethylurea mixture occurs with a decrease in the volume of the mixture at all temperatures, and the partial molar volumes of water and TMU increase with increasing temperature. The temperature dependences of the limiting partial molar isobaric thermal expansions of both components are characterized by the presence of the extremum. The obtained results are discussed in terms of solute-solvent and solute-solute interactions.

Preparation and characterization of amine (N-methyl diethanolamine)-based transition temperature mixtures (deep eutectic analogues solvents)

In this study, three mixtures of methylyltriphenylphosphonium bromide (MTPPB) as hydrogen bond acceptor (HBA) and N-methyl diethanolamine (MDEA) as hydrogen bond donor (HBD) component was used to prepare transition temperature mixtures (TTMs) into different mole ratios of 1:7, 1:10 and 1:16 HBA/HBD. Two important physicochemical properties of TTMs such as density and refractive index were investigated at the atmospheric pressure and temperature ranges of (293.15–353.15) K and (293.15–343.15) K, respectively. The experimental density data were used to derive the molar volume, molecular volume, lattice energy and isobaric thermal expansion coefficients. With the help of experimental refractive index data, the electronic polarization, molar refraction, and free volume were calculated at the whole temperatures. Several empirical equations were used to correlate refractive indices such as an empirical equation and one-parameter equations (Dale–Gladstone, Eykman, Lorentz–Lorenz, Newton, Arago–Biot, and Oster). Finally, the response surface methodology (RSM) was applied to evaluate the effects of two main factors such as temperature and mole ratio on the density and refractive index of TTMs. The results revealed that the molar ratio has almost a higher effect on the studied properties than temperature.

Physicochemical and thermodynamic properties of the {1-alkyl-1-methylpiperidinium bromide [C1Cn=2,4PIP][Br], or 1-butylpyridinium bromide, [C4Py][Br], or tri(ethyl)butylammonium bromide [N2,2,2,4] [Br] + water} binary systems

This work is a continuation of our comprehensive study of ionic liquids, ILs (including organic salts with melting temperature above 100 °C) and their aqueous solutions as a novel alternative working pair for the absorption heat pump. A series of organic salts: 1-ethyl-1-methyl-piperidinium bromide, [C1C2PIP][Br], 1-butyl-1-methyl-piperidinium bromide, [C1C4PIP][Br], 1-butylpyridinium bromide, [C4Py][Br] and tri(ethyl)butylammonium bromide, [N2,2,2,4][Br] have been synthesized. The structures of compounds have been confirmed using NMR spectra. The basic thermal characterization of pure organic salts, including temperature and enthalpy of phase transition (Ttr, ΔtrH), temperature and enthalpy of melting (Tfus, ΔfusH) have been measured using a differential scanning microcalorimetry technique (DSC). The physico-chemical properties that are: density (ρ) and dynamic viscosity (η) of the tested binary systems have been determined at wide temperature and composition range. From experimental densities data, the apparent molar volumes (Vϕ,1) were calculated. In order to obtain limiting apparent molar volumes (Vϕ,10), the concentration dependence of apparent molar volumes was correlated with Redlich–Mayer type equation. Additionally, the limiting molar expansibilities (Eϕ0) and isobaric thermal expansion coefficients (αP) have been calculated. Temperature dependence of the dynamic viscosity has been correlated using VFT equation. The solid−liquid phase equilibria (SLE) have been determined using a dynamic method and correlated using NRTL equation. The influence of the alkyl chain length in the piperidinium cation substituent, as well as the cation structure, on investigated properties are presented and discussed.

Volumetric properties of non-aqueous binary mixture of diethanolamine (DEA) and dimethylformamide (DMF)

This paper reports the volumetric properties such as density, molar volume and isobaric thermal expansion of non-aqueous system of DMF-DEA. The values of volumetric properties were reported for several mole fractions of DMF (x1) and DEA (x2) and temperature from 298.15 to 343.15 K. In order to investigate the significance of temperature and concentration on the each volumetric property and develop regression models, a user-defined method of response surface methodology (RSM) was applied. A predictive equation called Jouyban-Acree model (JAM) was used to predict the volumetric properties of the binary mixture. The accuracy and capability of JAM were compared with regression model. The results revealed that JAM is capable of correlating volumetric properties very well and is an accurate model for prediction of the volumetric properties of the binary mixture. The analysis of variance (ANOVA) results showed that temperature and concentration are highly significant and have the strong influence on the volumetric properties. The investigation of experimental data shows that the density and molar volume values increase with rising in the concentration of DEA in the mixture, while isobaric thermal expansion values decrease. Moreover, there was an increasing trend on the values of molar volume and isobaric thermal expansion as the temperature increased, whereas the density of binary mixture decreased with an increase in temperature.

Volumetric and ultrasonic studies on interactions of ethylene glycol, diethylene glycol and triethylene glycol in aqueous solutions of glycerol at temperatures T = (293.15 K − 308.15) K

Abstract Densities and ultrasonic speed of ethylene glycol, diethylene glycol and triethylene glycol in (0.00, 0.01, 0.03, 0.05) mol kg−1 aqueous solutions of glycerol have been measured at T = (293.15, 298.15, 303.15, 308.15) K and experimental pressure p = 0.1 MPa. From the density data, the apparent molar volume Vϕ, the partial molar volume V ϕ o and the partial molar volumes of transfer Δ V ϕ o have been calculated for glycols from water to aqueous glycerol solutions. Using ultrasonic speed values apparent molar isentropic compression Kϕ,s, partial molar isentropic compression K ϕ , s o and partial molar isentropic compression of transfer Δ K ϕ , s o , have been evaluated. The pair and triplet coefficients have been computed from partial molar volumes of transfer and partial molar isentropic compression of transfer. The apparent molar isobaric expansion at infinite dilution ( ∂ V ϕ 0 / ∂ T ) p , second order derivative ( ∂ 2 V ϕ 0 / ∂ T 2 ) p have also been calculated. The parameters thus obtained have been discussed in terms of (solute–solute)/(solute–solvent) interactions prevailing in the present ternary system along with structure making/structure breaking tendency of glycols in aqueous glycerol solutions.

Study of Intermolecular Interactions of CTAB with Amino Acids at Different Temperatures: A Multi Technique Approach

Abstract The densities, ρ, viscosities, η and specific conductivities κ, of (0.0002, 0.0004, 0.0006 and 0.0008 m) CTAB in 0.1 m aqueous valine, leucine and isoleucine were measured at different temperatures. The measured data were used to calculate various useful thermodynamic parameters. A complete characterization of any mixture can be performed by means of these thermodynamic properties. The apparent molar volume, ϕv , partial molar volume, ϕ v 0 $\phi _v^0$ and partial molar isobaric expansibilities, ϕ E 0 , $\phi _E^0,$ were calculated using density data. The viscosity data were analyzed using Jones–Dole equation to obtain viscosity coefficients, A- and B-, free energy of activation per mole of solvent, Δμ 1°∗, and solute, Δμ 2°∗, enthalpy, ΔH ∗ and entropy, ΔS ∗ of activation of viscous flow. Measuring the changes in these properties has been found to be an excellent qualitative and quantitative way to obtain information regarding the molecular structure and intermolecular interactions occurring in these mixtures. Various structure-making/breaking ability of solute (cetyltrimethylammonium bromide) in presence of aqueous amino acid solutions were discussed. In addition, fluorescence study using pyrene as a photophysical probe has been carried out, the results of which support the conclusions obtained from other techniques.

Density and Speed-of-Sound Measurements for Dilute Binary Mixtures of Diethylammonium-Based Protic Ionic Liquids with Water

Physicochemical properties of diethylammonium (DEA)-based protic ionic liquids and their aqueous solutions were obtained using experimental measurements of density (ρ) at different temperatures from T = (293.15 to 313.15) K and the speed of sound (w) at 298.15 K. Four DEA-based protic ionic liquids (PILs) with carboxylates as anions were synthesized. The standard entropy (S0) and lattice potential energy (UPOT) for pure PILs were estimated from molecular volumes at 298.15 K obtained using experimental density data. Apparent molar volumes (ϕV), isobaric expansivity (α), isentropic compressibility (βS), and isothermal compressibility (βT) have been obtained for aqueous solutions of PILs using experimental density and speed-of-sound data. These data have been further used to understand the electrostriction and concentration dependence of internal pressure. The Passynski method has been used to estimate concentration-dependent hydration numbers of PILs. The results obtained have been discussed in terms of con...

Interactions of Imidazolium Based Ionic Liquids with Water Studied by Density and Speed of Sound Measurements: Effect of the Chain Length of an Alkyl Substituent on the Imidazolium Ion

Densities and speeds of sound of three ionic liquids (ILs), 1-ethyl-3-methyl imidazoliumtetrafluoroborate (C2mimBF4), 1-butyl-3-methylimidazoliumtetrafluoroborate (C4mimBF4) and 1-hexyl-3-methylimidazoliumtetrafluoroborate (C6mimBF4) were measured in aqueous solutions at (288.15, 293.15, 298.15, 303.15 and 308.15) K. These data were used to calculate the volumetric properties apparent molar volume and apparent molar isentropic compression as a function of molality. Infinite dilution values for these properties were evaluated by an extrapolation procedure based on Redlich–Meyer type equations. Apparent molar isobaric expansions at infinite dilution were also obtained from the slopes of the apparent molar volume at infinite dilution versus temperature. All these properties are interpreted in terms of IL–water interactions. The hydrolysis of the \( {\text{BF}}_{4}^{ - } \) anion of the ILs and its effects on the results is discussed.

Effect of high pressure and temperature on the volume properties of the liquid-phase mixture of {water (1) + formamide (2)}

Compression, k = Δv/vo, was measured for the {water (1) + formamide (2)} binary mixture within the whole range of the component ratio at temperatures from 278.15 K to 323.15 K and pressure up to 100 MPa. Molar isothermal compressions, molar isobaric thermal expansions, isochoric coefficient of thermal pressure and internal pressure were calculated. Concentration dependences (from formamide content) of molar isothermal compressions for water + formamide mixtures at low pressure and temperature (close to 278.15 K) were featured with the minimum at x2 ≈ 0.1, which was smoothed over with both pressure and temperature increase. Molar isobaric thermal expansions of the mixture increased with the increase of formamide content in it at all state parameters; pressure increase resulted in temperature inversion in its concentration dependence, which shifted to the area of lower formamide (FA) concentration with the pressure increase. Isochoric coefficient of thermal pressure of the mixture drastically increased in the area of small FA additions. The temperature effect on the thermal pressure coefficient was opposite in the mixtures with high water and high formamide content. Calculated values for pure components were also compared.

Density and volumetric properties of the aqueous solutions of urea at temperatures from T = (278 to 333) K and pressures up to 100 MPa

Abstract This paper highlights the values of densities of aqueous solutions of urea in the concentration range m (from 0.1809 to 12.801) mol·kg−1 at T = (278.15, 288.15, 298.15, 308.15, 323.15 and 333.15) K and at p = (0.101, 10, 25, 50, 75 and 100) MPa. The densities were also measured for dilute aqueous solutions m (from 0.093 to 2.505) mol·kg−1 with temperature from 274.15 to 283.15 K, with increment of 1 K at atmospheric pressure, in order to study the effect of urea on the temperature of the maximum water density. Volumetric properties calculated from the density, such as apparent molar volumes of urea, Vɸ,2, molar isothermal compressions, KT,m, and molar isobaric thermal expansions, EP,m, of solution are considered depending on concentration, temperature and pressure. Also, certain volumetric characteristics for infinitely diluted urea in water were obtained: the limiting partial molar volumes, V 2 ∞ ; limiting partial molar isothermal compressions, K T , 2 ∞ ; and limiting partial molar isobaric thermal expansions, E P , 2 ∞ . Obtained results are discussed from the standpoint of solute – solute and solute – solvent interactions. With the help of various approaches based on volumetric characteristics, the character of the disturbing effect of urea on the water structure was described.

Densities and Volumetric Properties of Aqueous Solutions of {Water (1) + N-Methylurea (2)} Mixtures at Temperatures of 274.15–333.15 K and at Pressures up to 100 MPa

Densities of the mixture {water (1) + N- methylurea (2)} in the concentration range to mole fraction x2 = 0.07071 (or to the solution molality concentration m2 = 4.22335 mol·kg–1) at atmospheric pressure in the temperature range from 274.15 to 333.15 K and compression k = ΔV/V0 at pressures to 100 MPa (10, 25, 50, 75, and 100) in the temperature range from 278.15 to 323.15 K (278.15, 288.15, 288.15, 308.15, 323.15) in the same concentration range were calculated in this study. The apparent molar volumes of N-methylurea Vϕ,2 and the partial molar volumes of both components V̅1 and V̅2 in the mixture, molar isothermal compressibilities KT,m, molar isobaric thermal expansions EP,m, and isochoric coefficients of thermal pressure β of the mixture were calculated. Moreover, volumetric measures for the infinitely dilute solution of N-methylurea solution were calculated: limiting partial molar volumes V̅2∞, the limiting partial molar isothermal compressibilities K̅T,2∞, and the limiting partial molar isobaric thermal expansions E̅P,2∞. The results obtained are discussed from the point of view of solute–solvent and solute–solute interactions.

Density and refractive index measurements of transition-temperature mixture (deep eutectic analogues) based on potassium carbonate with dual hydrogen bond donors for CO2 capture

The transition-temperature mixture (TTM) is a new type of solvent and is known as a tuneable solvent similar to deep eutectic solvent (DES). The new type of solvent called ternary transition-temperature mixture (TTTM) was prepared to use for CO2 capture purposes. In this work, TTMs and TTTMs were prepared with potassium carbonate (PC) as a hydrogen bond acceptor (HBA) and three hydrogen bond donors (HBDs) such as glycerol (GL), ethylene glycol (EG) and 2-amino-2-methyl-1-3-propanediol (AMPD) known as a hindered amine (HA). Binary TTMs were PC-GL with mole ratios 1:10 and 1:16 and PC-EG with the same mole ratios. TTTMs were prepared by adding AMPD in binary TTMs such as PC-GL-AMPD 1:16:1 and PC-EG-AMPD 1:10:1. The experimental density and refractive index of all mixtures were measured at temperatures from 293.15 K to 343.15 K with an interval of 5 K. The effect of temperature, mole ratio, molar massand alkyl chain length on the properties was investigated. The molar volumes and isobaric thermal expansion were calculated using experimental density data. The experimental refractive index values were used to derive the specific refraction, molar refraction, free molar volume, electronic polarization and polarizability at several temperatures.

Effect of high pressure and temperature on volumetric properties of {water (1) + ethylenediamine (2)} mixtures

For {water (1)+ethylenediamine (2)} binary mixture the densities at atmospheric pressure and compressions, k=ΔV/Vo, at pressures from 10 to 100MPa of have been measured over the whole concentration range and temperatures from 278.15 to 323.15K. The molar isothermal compressions and molar isobaric expansions, the thermal pressure coefficients and the internal pressure of water+ethylenediamine mixture have been calculated at all state parameters examined. It was shown that the values of molar isothermal compression and molar isobaric expansion of the mixtures rich in water varied insignificantly whereas the thermal pressure coefficients changed strongly within that concentration range. The magnitude of the extreme on the concentration dependence of the thermal pressure coefficient was unusually large that was probably connected with the influence of 2H2O-EDA hydrate complex.