Apparent Molar Volumes Vφ Research Articles

Volumetric Properties for the Aqueous Solution of Yttrium Trichloride at Temperatures from 283.15 to 363.15 K and Ambient Pressure

To effectively develop the rare earth elements resources from the geothermal waters, it is essential to understand the volumetric properties of the aqueous solution system to establish the relative thermodynamic model. In this study, densities of YCl3 (aq) at the molalities of 0.08837–1.60639 mol·kg−1 from 283.15 K to 363.15 K at 5 K intervals and ambient pressure were measured experimentally by an Anton Paar digital vibrating-tube densimeter. Based on experimental data, the volumetric properties including apparent molar volume (Vϕ) and the coefficient of thermal expansion of the solution (α) of the binary systems (YCl3 + H2O) were derived. The 3D diagram (mi, T, Vϕ) of apparent molar volumes against temperature and molality was plotted. On the basis of the Pitzer ion-interaction model of electrolyte, the Pitzer single-salt parameters ( β MX 0 v , β MX 1 v , and C MX v ) for YCl3 and temperature-dependence equation F(i, p, T) = a1 + a2ln(T/298.15) + a3(T-298.15) + a4/(620-T) + a5(T-227) as well as their coefficients ai (i = 1–5) in the binary system were obtained for the first time. The values of Pitzer single-salt parameters of YCl3 agree well with the calculated values corresponding to the temperature-dependence equations, indicating that single-salt parameters and temperature-dependent formula obtained in this work are reliable.

Effect of some choline based deep eutectic solvents on volumetric and ultrasonic properties of gabapentin drug in water at T = (288.15 to 318.15) K

A key part of the drug preparation process is the optimization of molecular interactions between drugs and solvents. Thermodynamic properties provides complete information on interactions and the selection of suitable solvents for various pharmaceutical processes. Especially, the investigation of antiepileptic drugs in aqueous solutions has been a subject of interest because they employ their effect by interaction with biological membranes. In this study, the density and speed of sound for the gabapentin (GBP) in aqueous deep eutectic solvents (DESs), (choline chloride/ethylene glycol (ChCl/EG), choline chloride/glycerol (ChCl/Gly), and choline chloride/urea (ChCl/U)) as novel category of green solvents were measured at temperature range 288.15 K to 318.15 K. The apparent molar volumes Vφ, apparent molar isobaric expansion Eφ0, Hepler’s constant and apparent molar isentropic compressibility κφ were calculated from the density and speed of sound data. Findings show that Vφ values are higher for binary systems compared to ternary systems. The order of Vφ values for aqueous DESs solutions are as follows: ChCl/EG > ChCl/U > ChCl/Gly. The standard partial molar volume Vφ0 and partial molar isentropic compressibility κφ0 were obtained by using the Redlich-Meyer equation. The obtained results for the Vφ0 quantity indicate a strong interaction between the GBP drug and the ChCl/Gly. Finally, using the results of Eφ0, it is understood that GBP has acted as a structure maker in the presence of all DESs.

A Simple 1–1 Electrolyte: Volumetric Properties of Aqueous Solutions of Sulfuric Acid at Elevated Temperatures

Densities of aqueous solutions of sulfuric acid (H2SO4) have been measured by vibrating tube densimetry at molalities m varying from 0.02 to 3.0 mol·kg–1, at temperatures over the range 323.15 ≤ T/K ≤ 523.15 at 10 MPa pressure. These results were used to calculate the corresponding apparent molar volumes Vϕ(H2SO4,aq) and appear to be the first-ever systematic study of the volumetric properties of this important acid at elevated temperatures. At T ≤ 373.15 K, the present results aligned well with recent literature data and with values reported in the 1926 International Critical Tables. No reliable experimental data were found for comparison at higher temperatures. The present results confirm that at lower concentrations and temperatures, sulfuric acid solutions exist as a variable mixture of H+(aq) + HSO4–(aq) + SO42–(aq). However, at higher temperatures, the degree of association increases markedly such that at T ≥ 448.15 K, sulfuric acid solutions behave like a simple 1:1 electrolyte [H+(aq) + HSO4–(aq)] even at low concentrations. The variation of Vϕ(H2SO4,aq) over the entire experimental region was well modelled using a simple Pitzer equation that specifically included (where appropriate) the effects of chemical speciation. Combination of this model with relevant literature data enabled estimation of the standard ionic volume V°(HSO4–,aq) and the standard volume change ΔrV° for the reaction H+(aq) + SO42–(aq) → HSO4–(aq) at temperatures up to 523 K.

Effect of position of OH group in isomeric butanediols on intermolecular interaction with Choline Acetate: A thermodynamic study at different temperatures

The prominent effect of the position of hydroxyl groups in isomeric butanediols i.e.1,3-butanediol (1,3-BTD), 1,2-butanediol (1,2-BTD) and 2,3-butanediol (2,3-BTD) on intermolecular interactions with Choline Acetate has been investigated using various thermophysical parameters such as density ρ, speed of sound u, refractive index nD and specific conductivity κ over different concentration range and at temperatures varying from 293.15 to 323.15 K at atmospheric pressure. To gain further insight the derived parameters such as apparent molar volumes Vϕ, apparent molar isentropic compressibilities Ksϕ, and their infinite parameters mainly limiting apparent molar volumes at infinite dilution Vϕo, limiting apparent molar expansibilities Eϕo, limiting isentropic compression Kϕo, molar refraction Rm and infinite molar conductance ̂mo values have been calculated. The least values obtained for apparent molar volumes and compressibilities in case of 1,3-BTD mixtures are attributed to its highest ability to form intramolecular hydrogen bonding among isomeric butanediols and thus lesser availability to interact with Choline Acetate molecules. However for 2,3-BTD and 1,2-BTD binary mixtures the results have been explained on the basis of hydrophobic or iceberg effect where alkyl groups are present either on one end (1,2-BTD) or at both ends (2,3-BTD) while OH groups are located at vicinal carbon atoms.

Effect of α–amino acids (glycine, l-alanine, l-valine and l-leucine) on volumetric and acoustic properties of aqueous 1-Butyl-3-propylimidazolium bromide at T = (288.15, 298.15, 308.15, 318.15) K

In this experimental work, values of density and speed of sound of some α–amino acids viz.; glycine, l-alanine, l-valine and l-leucine with different molal concentrations of IL; 1-Butyl-3-propylimidazolium bromide ([BPim][Br]) at four working temperatures and experimental pressure p = 0.1 MPa have been determined. Using the corresponding data, different thermo physical parameters like apparent molar volume Vϕ, partial molar volume (Vϕ0), standard partial molar volume of transfer (ΔVϕ0), apparent molar isentropic compression (Kϕ,s), partial molar isentropic compression (Kϕ,s0) and partial molar isentropic compression of transfer (ΔKϕ,s0) have been calculated. Interaction coefficients have been determined using McMillan–Mayer theory and IR spectral studies have also been performed to validate the results obtained. The structural behaviour of all the α–amino acids (α-AAs) under consideration in ([BPim][Br]) and various types of interactions occurring in the ternary systems have been predicted from the results of various parameters.

Chemical speciation effects on the volumetric properties of aqueous sulfuric acid solutions

Densities of fifteen aqueous solutions of sulfuric acid (H2SO4) have been measured by vibrating-tube densimetry at solute molalities (m) from (0.01 to 3.0) mol·kg−1 over the temperature range 293.15 ≤ T/K ≤ 343.15. These data have been used to calculate the corresponding apparent molar volumes Vϕ(H2SO4,aq), which represent a significant expansion of the volumetric database for this industrially-important acid. At 298.15 K the present results agree well with literature data, notably with the century-old values given in the 1926 International Critical Tables. At other temperatures, where comparisons are possible agreement with the present Vϕ values is also very satisfactory. Consistent with earlier studies, Vϕ(H2SO4,aq) was found to exhibit an abnormally-large decrease at low concentrations (m ≤ 0.1 mol·kg−1). This effect is consistent with a change in the chemical speciation of H2SO4(aq), from an essentially 1:1 electrolyte (H+(aq) + HSO4− (aq)) at higher concentrations to a predominantly 1:2 electrolyte (2H+(aq) + SO42− (aq)) in dilute solutions. The Vϕ values were modelled using variants of Young’s rule and the Pitzer formalism. Combination of these results with literature values for the standard volume V°(SO42−,aq) enabled estimation of V°(HSO4−,aq) and the standard volume change, ΔrV°, for the first protonation of the sulfate ion (H+(aq) + SO42−(aq) → HSO4−(aq)) as functions of temperature. It is shown that V°(HSO4−,aq) is sensitive to the value of the first protonation constant and probably cannot be determined to better than ± 0.3 cm3·mol−1 at present.

Volumetric and acoustic properties of amino acids L-Leucine and L-Serine in aqueous solution of ammonium dihydrogen phosphate (ADP) at different temperatures and concentrations

The physicochemical properties of amino acids like L-Leucine and L-Serine in aqueous solution of ammonium dihydrogen Phosphate (ADP) at different temperature analysed by volumetric and acoustic methods. By using density data, apparent molar volume Vϕ, partial molar volume Vϕ0 and standard partial molar volume of transfer ΔVϕ0 have been evaluated. From speed of sound data, apparent molar isentropic compression Kϕ,s apparent partial molar isentropic compression Kϕ,s0 and partial molar isentropic compression of transfer ΔKϕ,so have been calculated. The pair and triplet interaction coefficient have also been calculated. The results have been interpreted in terms of solute–solute and solvent–solvent interactions.

Study of deep eutectic solvents (DESs) performance on aromatics (benzene and thiophene) extraction: thermophysical study

Thermophysical properties of some binary mixtures of novel choline chloride-based deep eutectic solvents and two aromatics (benzene and thiophene) were measured to evaluate the nature of solute–solvent interactions at T = (283.15–303.15) K and atmospheric pressure. Choline chloride was selected as hydrogen bond donor and (mono-, di- and tri-) ethylene glycols or (mono-, di- and tri-) ethanolamines were used as hydrogen bond donors. The density (d), speed of sound (u), viscosity (η) and refractive index (nD) data were measured for binary mixtures of benzene or thiophene with the selected DESs at T = (283.15–303.15) K. The apparent molar volume (Vφ), standard partial molar volume (Vφ0 ), partial molar isentropic compression (κφ0 ), excess molar volume (VE), viscosity B-coefficient and molar refraction (RD) values, were obtained for the binary mixtures at dilute region of aromatics. These quantities are used for interpreting of the studied DESs and benzene or thiophene molecular interactions. Also, the scaled particle theory (SPT) was used for calculation of interaction volume (Vint), and cavity volume (Vcav). The obtained results indicate that DESs with amine functional groups interact more effectively with benzene or thiophene rather than ethylene glycolic-based DESs.

Intermolecular Interactions in 1,6-Diaminohexane + Water Mixtures at 293.15 to 333.15 K

The density (ρ) and viscosity (η) of the mixtures of 1,6-diaminohexane (DAH) + water binary system were determined over the whole composition range at p = 101 kPa from 293.15 to 333.15 K. The measured density and viscosity values decrease with the increase of temperature. In addition, the viscosity of the binary system shows a maximum value along with the molar fraction of DAH. According to the experimental data, excess molar volume (VE), apparent molar volume Vϕ, viscosity deviation (Δη), and excess Gibbs free energy (ΔG*E) of the activation of viscous flow were obtained and correlated by the well-known Redlich–Kister type polynomial equation by using the least square method and regression parameters were calculated. It was found that all of the VE values are negative while $$\Delta \eta $$ and ΔG*E values are positive. The intermolecular interactions between DAH and water were characterized by the averaged non-covalent interaction index (aNCI) and thermal fluctuation index (TFI) method. The obtained results proved that N···H–O and O···H–N hydrogen bonds which lightly affected by thermal motion, and some of the flexible van der Waals interactions are the reason for the specific variation of the viscosity and excess properties of the studied binary system.

Effect of proteinogenic amino acids l-serine/l-threonine on volumetric and acoustic behavior of aqueous 1-butyl-3-propyl imidazolium bromide at T = (288.15, 298.15, 308.15, 318.15) K

In the present work, density ρ, speed of sound u and FT-IR studies of l-serine and l-threonine have been carried out in (0.01, 0.03 and 0.05) mol kg−1 of 1-butyl-3-propyl imidazolium bromide ([BPim][Br]) at different temperatures (288.15 K, 298.15 K, 308.15 K, 318.15 K) at experimental pressure p = 0.1 MPa. Based on the measured densities, different thermo physical parameters like apparent molar volume Vϕ (AMV), partial molar volume Vϕ0 (PMV) and standard partial molar volume of transfer ΔVϕ0 have been calculated whereas from data of speed of sound; apparent molar isentropic compression Kϕ,s, partial molar isentropic compression Kϕ,s0 and partial molar isentropic compression of transfer ΔKϕ,s0 have been depicted. Transfer parameters have also been calculated and used to compute the pair and triplet interaction coefficients. Infrared spectral studies have also been performed in order to verify the results obtained. The work is mainly focused on prediction of various interactions present in the ternary system consisting of amino acids (AAs), 1-butyl-3-propyl imidazolium bromide ([BPim][Br]) and water.

Volumetric and acoustic approach for investigating molecular interactions of choline acetate ionic liquid in α,ω-alkanediols at different temperatures

Various thermophysical parameters such as density ρ, ultrasonic sound velocity u, refractive index nD, and specific conductivity κ of 2-hydroxyethyl-trimethylammonium acetate; [(C2H4OH)-(CH3)3N] [Acetate] or Choline Acetate in α,ω-alkanediols viz. 1,2-Ethanediol (1,2-ED), 1,3-Propanediol (1,3-PPD), 1,4-Butanediol (1,4-BTD) and 1,5-Pentanediol (1,5-PTD) have been investigated over various concentrations (0.02–0.4 mol/kg) and at temperatures ranging from 293.15 to 323.15 K at atmospheric pressure. In order to determine the effect of OH spacing in α,ω-alkanediols on the molecular interactions in solutions, the thermodynamic properties and derived parameters at infinite dilution such as apparent molar volumes Vϕ, apparent molar compressibilities KSϕ, apparent molar volume at infinite dilution Vϕ0 , limiting apparent molar expansibilities ϕE0, limiting isentropic compression KSϕ0 have been calculated. The calculated parameters in the mixtures have been interpreted in terms of increasing hydrophobicity due to the successive addition of –CH2 unit in α,ω-alkanediols. The results have been further supported using polarizability (α) and conductivity studies. The experimental observations have also been supported by DFT calculations in terms of the interaction energies of cation and anion of Choline Acetate in solutions containing α,ω-alkanediols.

Volumetric Properties in the NaAsO2 + H2O System at Temperature from 283.15 to 363.15 K and Atmospheric Pressure

Densities of sodium arsenite (NaAsO2) aqueous solution with the molality varied from 0.19570 to 1.94236 mol·kg−1 at temperature intervals of 5 K from 283.15 to 363.15 K and 101 ± 5 kPa were measured by a precise Anton Paar Digital vibrating-tube densimeter. Apparent molar volumes (VΦ) and thermal expansion coefficient (α) were obtained on the basis of experimental data. The 3D diagram of apparent molar volume against temperature and molality and the diagram of thermal expansion coefficient against molality were generated. According to the Pitzer ion-interaction equation of the apparent molar volume model, the Pitzer single-salt parameters (βM,X0υ, βM,X1υ, βM,X2υ, and CM,Xυ, MX = NaAsO2) and their temperature-dependent correlation F(i, p, T) = a1 + a2ln (T/298.15) + a3(T − 298.15) + a4/(620 − T) + a5/(T − 227) (where T is temperature in Kelvin and ai are the correlation coefficients) for NaAsO2 were obtained for the first time. The predictive apparent molar volumes agree well with the experimental values, and those results indicated that the single-salt parameters and the temperature-dependent formula are reliable.

Apparent molar volumes and relative viscosity of [C3C1PYR][Br]/[C2OHC1PYR][Br] + H2O

The binary mixtures of 1-propyl-1-methylpyrrolidinium bromide ([C3C1PYR][Br]) salt and 1-hydroxyethyl-1-methylpyrrolidinium bromide ([C2OHC1PYR][Br]) salt with secondary distilled water were prepared at low concentrations. The density and viscosity of the studied binary mixtures have been determined. The values of the studied properties were recorded every 5 K at temperature range 288.15–318.15 K. The values of apparent molar volume (Vϕ, m3 mol−1) and relative viscosity (ηr) were calculated according to the experimental values of density and viscosity of the systems. The side chains effects in each salt cation are discussed on the above properties. The limiting parameters (Vϕ0, m3 mol−1) were obtained and analyzed by fitting the apparent molar volumes with concentration by a Redlich–Rosenfeld–Meyer equation. The relative viscosities (ηr) were also calculated and analyzed according to the traditional equation of Jones–Dole at different concentration ranges.

Volumetric Properties of Amino Acids in Aqueous Solutions of Glucosamine Hydrochloride at T = 293.15–313.15 K

The densities (ρ) of glycine, L-alanine, L-serine, and L-threonine solutions in 0.05, 0.10, 0.15, 0.20, and 0.30 mol kg–1 aqueous solutions of D-glucosamine hydrochloride have been measured at T = 293.15, 298.15, 303.15, 308.15, and 313.15 K. The apparent molar volumes (Vϕ), limiting partial molar volumes ($$V_{\phi }^{0}$$) of the amino acids have been calculated from the density data. Transfer partial molar volumes (∆tr$$V_{\phi }^{0}$$) and hydration numbers from water to the aqueous solutions of D-glucosamine hydrochloride were also obtained. These parameters of volumetric properties can help to understand the mixing effects and interactions between amino acids and D-glucosamine hydrochloride aqueous solution.

Probing molecular interactions between Choline Acetate Ionic Liquid and Alcohols: A comparable thermophysical study of Choline Acetate Ionic Liquid with change in solvent polarities

In order to understand the effect of solvent permittivity on the molecular interactions in solutions, various thermophysical parameters such as density ρ, ultrasonic sound velocity u, refractive index nD, and specific conductivity ˄m of 2-hydroxyethyl-trimethylammonium Acetate; [(C2H4OH)-(CH3)3N] [Acetate] or Choline Acetate in alcohols viz. ethanol, 1-propanol and 1-butanol have been investigated over the entire concentration range at temperatures ranging from (293.15 to 323.15) K at atmospheric pressure. Further, derived thermodynamic properties and parameters at infinite dilution such as apparent molar volumes Vϕ, apparent molar compressibilities KSϕ, apparent molar volume at infinite dilution Vϕ0, limiting apparent molar expansibilities ϕE0, limiting isentropic compression KSϕ0 have been calculated. The “Kosmotropic” or “structure making” ability of Choline Acetate decreases for each additional alcohol CH2 group revealing that the Choline Acetate shows greater order-making effect in ethanol. The results further have been verified by calculating molar refraction RM and limiting molar conductance˄mo values which showed that Choline Acetate has greater interaction with the solvent having high polarity i.e. ethanol. The experimental observations have been also supported by DFT calculations which are in agreement with more structural modification of Choline Acetate in Ethanol than in 1-propanol and 1-butanol.

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.

Temperature dependent volumetric and acoustic properties of some amino acids in aqueous solutions of an antidepression drug

The interactions of amino acids (histidine, valine and glycine) with drug amitriptyline as a subordinate of temperature have been perused by combination of volumetric and acoustic methods. Densities and speeds of sound of histidine, valine and glycine in aqueous solutions of amitriptyline have been measured at T = (305.15, 310.15 and 315.15) K. Apparent molar volume Vφ, apparent molar isentropic compression kφ, s, of amino acids (solute) in binary aqueous solutions of (0.0006, 0.001, 0.002 and 0.004) mol. kg−1 amitriptyline (solvent) have been designated at reported temperatures. The mentioned parameters are used to construct the solute–solvent interactions in ternary systems. The dependency of these parameters on concentration, temperature and hydrocarbon chain length of the amino acids clearly suggest the roles of amino acids in solute-solvent interactions.

Exploration of solute-solvent interactions in aqueous mixtures of monosaccharides and triammonium citrate (TAC) at different temperatures: Volumetric and acoustic approach

The present study reports the densities, ρ and speeds of sound, u of monosaccharides (D (+) -xylose and D (−)-ribose) in aqueous triammonium citrate (TAC) solutions at temperatures, T = (288.15, 298.15, 308.15 and 318.15) K and at experimental pressure, p = 0.1 MPa. The available data is used to calculate the thermophysical parameters like apparent molar volumes Vϕ, apparent molar isentropic compressibilities Kϕ,s, partial molar volumes, Vϕo and partial molar isentropic compressibilities, Kϕ,soand then the partial molar volumes of transfer, ΔVϕoand partial molar isentropic compression of transferΔKϕ,soare evaluated. Further, the expansion coefficients, (∂Vϕ0/∂T)p, (∂2Vϕ0/∂2 T)p, pair (VAB, KAB) and triplet (VABB, KABB) interaction coefficients have also been determined. These parameters have been discussed to ascertain the solute co-solute interactions. Apparent specific volumes ASV and hydration numbers Nw are also calculated to check the taste behaviour and hydration behaviour respectively.

The study of molecular interactions of aqueous solutions of Choline Acetate at different temperatures

Thermophysical properties viz. density ρ, speed of sound u, refractive index nD, and specific conductivity κ for aqueous solution of ionic liquid; 2-hydroxyethyl-trimethylammonium Acetate; [(C2H4OH)-(CH3)3N] [Acetate] (Choline Acetate) have been studied over the whole concentration range at different temperature (293.15 to 323.15) K at atmospheric pressure in order to understand the molecular interactions between solvent and solute. To have more insight of solute–solvent interactions occurring in aqueous solutions of Choline Acetate, apparent molar volume Vφ, apparent molar volume at infinite dilution Vφ0, limiting apparent molar expansibilities φE0, apparent molar compressibility KSφ, limiting isentropic compression KSφ0, molar refraction RM and limiting molar conductance ∧omhave been calculated over the whole composition range as a function of ionic liquid concentration. Thermophysical results confirm the presence of strong solute-solvent interactions in the aqueous solutions of Choline Acetate, which gets stronger with increase in temperature. Also, computational studies have been carried out for deeper understanding of interactions of aqueous solutions of Choline Acetate at molecular level by using Density Functional Theory (DFT). These results show that solute-solute interactions in Choline Acetate decreases on addition of water solvent hence are in good agreement with thermophysical results.

Acoustic, volumetric and spectral studies of binary liquid mixtures of aliphatic dialkylamine and 2-alkanols at different temperatures

This article reports experimental densities ρ and speeds of sound (u) for the binary mixtures of di-n-butylamine and diisopropylamine with 2-butanol and 2-pentanol at a temperature range of (293.15–308.15) K with a temperature step of 5 K over entire composition range and at atmospheric pressure. Various thermodynamic parameters have been calculated using experimental data of densities and speeds of sound. The different parameters calculated are excess molar volume VmE, excess isentropic compressibilities κsE, deviations in speed of sound uD, apparent molar volumes Vϕ, partial molar volumes V¯m, excess partial molar volumes V¯mE excess intermolecular free lengths LfE and excess acoustic impedance ZE. These parameters have been analysed in terms of nature and extent of intermolecular interactions. Effects of temperature, chain length and branching on intermolecular interactions have also been examined. Apart from this, FT-IR spectroscopy technique has also used to find more support for the results obtained from the calculated thermodynamic parameters. All the calculated properties have been correlated using Redlich-Kister type polynomial equation by the method of least-squares for the estimation of the binary coefficients and the standard deviations.