Standard Partial Molar Volumes Research Articles

Effect of presence of tetra alkyl ammonium bromides on solution behavior of 1-Butyl-2, 3-dimethylimidazolium chloride at different temperatures: Volumetric and acoustic studies

Abstract Densities (ρ) and ultrasonic velocities (u) of 1-Butyl-2,3-dimethylimidazolium chloride, [bdmim]Cl, in aqueous solutions of tetra-n‑butyl ammonium bromide (TBAB) and tetra-n-propyl ammonium bromide (TPAB) have been measured at T = (298.15 to313.15)K. The apparent molar volume, Vϕand the apparent molar isentropic compressibility, Kϕ, s of the IL have been calculated. Both limiting apparent molar volume, V ϕ 0 and limiting apparent molar isentropic compressibility, K ϕ , S 0 were calculated using Redlich-Rosenfeld-Meyer (RRM) type equation and these values are compared with Masson type equation. The positive value of limiting apparent molar expansivity, E ϕ 0 indicates the ionic liquid (IL) has structure making effect. The increase in standard partial molar volume of transfer, Δ V ϕ 0 and standard partial molar isentropic compression of transfer, Δ K ϕ , S 0 of [bdmim]Cl with increasing TBAB concentrations has been explained by Friedman-Krishann co-sphere model. Moreover, some acoustic parameters were estimated using the experimental data at T= (298.15–313.15) K for justifying several interactions in the ternery solutions.

Densities and thermal expansions of (water + tetrahydrofuran) mixtures within the temperature range from (274.15 to 333.15) K at atmospheric pressure

The mixture {water (1) + tetrahydrofuran (2)} densities have been measured over the whole composition range at temperatures between (274.15 and 333.15 K) and atmospheric pressure using the vibration type densimeter. Values of excess molar volume and molar isobaric thermal expansion of the mixture as well as apparent/partial molar volumes (down at infinite dilution) for water and tetrahydrofuran (THF) have been calculated. It is shown that the formation of the water + THF mixture occurs with decreasing its volume under all the temperatures. Concentration dependences of partial molar volumes of water and THF are characterized by the presence of extreme regions. Standard (limiting) partial molar volumes of water and THF increase as the temperature is rising. Increase in both temperature and THF content influence on the value of molar isobaric expansion of the mixture in the same way.

Interactions of sodium salicylate and β-cyclodextrin in water: A volumetric, ultraacoustic and optical study

Present article reports the thermodynamic studies on standard transfer volumes and compressibilities of non-steroidal anti-inflammatory drug, sodium salicylate in 0.0005, 0.001, 0.004, 0.009, 0.0140 mol·kg−1 aqueous-β-cyclodextrin solutions at 303.15, 308.15 and 313.15 K. The transfer properties have been calculated from the standard partial molar volumes and compressibilities determined form the linear dependence of corresponding apparent molar properties over the drug concentration. Apparent molar properties have been calculated from measured density and ultrasonic velocity data. Further, the optical property, refractive index (n) of the studied drug solutions has been measured. In addition to this, the quantum mechanical calculations were performed using the DFT. The solvation energy (ΔESol), relative stabilization energy (ΔERel), complexation energy (ΔEComp) and change in the volume (ΔV) of the different complexes have been calculated. The results have been discussed in terms of the drug-solvent and drug-β-cyclodextrin interactions. The complex formation of sodium salicylate with β-cyclodextrin with dominating lateral interactions namely ion-hydrophilic/hydrophilic-hydrophilic or hydrogen bonding interactions has been confirmed from standard partial molar properties and computational studies.

VOLUMETRIC PROPERTIES OF ACRYLONITRILE+ETHANOL MIXTURE OVER TEMPERATURE RANGE FROM (293.15 TO 323.15) K AT AMBIENT PRESSURE

Densities of binary mixture of acrylonitrile in ethanol have been measured over the full range of compositions at temperatures from 293.15K to 323.15 K at the ambient pressure (87.9 kPa). The volumetric properties such as excess molar volumes, apparent molar volumes, partial molar volumes, excess partial molar volumes, standard partial molar volumes for binary mixture were calculated. Excess molar volumes were described by the Redlich–Kister polynomial equation. The Redlich–Kister coefficients and the standard deviations were calculated as well. The excess molar volumes exhibit mainly negative deviations from the ideal behavior over the whole range of composition for acrylonitrile+ethanol binary mixtures at low temperatures and become less negative with increasing temperature from 293.15 to 323.15 K. The results are interpreted on the basis of strong interaction between group of acrylonitrile and OH group of ethanol by hydrogen bonding. However, the sigmoid shape of plots of excess molar volumes versus molar fraction of ethanol from positive to negative values indicates to the varying interactions depending upon the composition of binary mixtures. Moreover, it is also attributed to the self-associating effect of ethanol therefore the self-associates of acrylonitrile by dipole-dipole interactions and the self-associates of ethanol by hydrogen bonding between same molecules at low concentrations predominate too.

Volumetric and Ultrasonic Studies on Interactions of Glycols in Aqueous Solutions of Xylitol at Different Temperatures

In order to arbitrate and understand the synergy between the sugar alcohol xylitol and glycols, the volumetric and acoustical parameters are being calculated from the experimental speed of sound and density data at a variation of temperature from 288.18 to 318.15 K, in (0.01, 0.02, and 0.03) mol·kg–1. Volumetric parameters, such as Vϕ, that is, apparent molar volume, and ΔVϕ0, that is, standard partial molar volume of transfer, in the aqueous solutions of xylitol for the glycols have been calculated with the experimental density data. The Vϕ0 values show accretion with temperature and thus imply that the solute and solvent interaction for triethylene glycol in aqueous xylitol is more as compared to ethylene glycol and diethylene glycol. Similarly, with the help of the speed of sound data, the acoustical parameters such as Kϕ,s, that is, apparent molar isentropic compression, and ΔKϕ,s0, that is, partial molar isentropic compression of transfer, have been computed along with the pair and triplet interaction coefficients.

Volumetric, acoustic and infrared spectroscopic study of amino acids in aqueous solutions of pyrrolidinium based ionic liquid, 1–butyl–1–methyl pyrrolidinium bromide

The effect of ionic liquid, 1–butyl–1–methyl pyrrolidinium bromide [C4C1Pyrr]Br on the thermodynamic properties of glycine, L–alanine and L–valine in aqueous solution was studied at the temperature range of 288.15–308.15 K and experimental pressure of p = 0.1 MPa by density, ultrasonic speed and FTIR spectroscopic techniques. Apparent molar volumes, standard partial molar volumes, standard partial molar volumes of transfer and hydration number are evaluated using density data. Side chain contributions and temperature dependence of partial molar volume have been calculated. Apparent molar isentropic compression, standard partial molar isentropic compression, standard partial molar isentropic compression of transfer and hydration number have been calculated using ultrasonic speed data. Fourier transform infrared (FTIR) spectral studies have also have been carried out for the present mixture. These volumetric, acoustic and spectroscopic studies can help to understand the mixing effects and other complex biological processes between amino acids and ionic liquid aqueous solution.

Liquid-liquid equilibria and thermophysical properties of ternary mixtures {(benzene / thiophene) + hexane + deep eutectic solvents}

In this work, thermophysical properties were determined for understanding of solute-solvent interactions in (aromatics + deep eutectic solvents). The standard partial molar volume (V0ϕ), partial molar isentropic compressibility (κ0ϕ), and viscosity B-coefficient were determined for the mixtures at dilution region of aromatic compounds. The liquid-liquid equilibria (LLE) for ternary mixtures including (n-hexane + benzene or thiophene + N-formylmorpholine (NFM) or sulfolane (SULF) or diglycolamine (DGA) or deep eutectic solvents (DESs)) were determined at T = (303.15–313.15) K. The performance of the studied solvents or DESs were investigated by distribution coefficient (β) and selectivity (S) in liquid-liquid extraction. The NRTL activity coefficient model was used to correlate LLE data.The experimental results indicate the good performance of DGA-containing DES in comparison with NFM and SULF at the ambient condition. The results of LLE data and calculated thermophysical parameters confirm each other.

Partitioning of anticancer drug 5-fluorouracil in micellar media explored by physicochemical properties and energetics of interactions: Quantitative insights for implications in drug delivery

Drug delivery vehicles such as micelles, vesicles and other nanoemulsions are necessary for enhanced bioavailability of drugs in the body. We have measured and correlated physicochemical properties of an anticancer drug 5-fluorouracil in the micelles of anionic surfactant sodium dodecyl sulfate. cationic surfactant hexadecyltrimethylammonium bromide, and non-ionic surfactant triton X-100 with the energetics of interactions. Thermodynamic signatures accompanying the partitioning of drug into surfactant micelles along with standard partial molar volume and standard partial molar compressibilities of transfer from water to the micelles have been interpreted in terms of strength, nature and extent of partitioning. Functional groups on the drug responsible for interaction/partitioning in micelles have been identified. Interaction of 5-fluorouracil in two or three sequential partitioning behavior depending on the nature of the surfactant micelles has enabled detailed mechanistic analysis of the partitioning process. Structure-property-energetics relationship to obtain deeper insights into the nature of interaction between the drug and micelles has been addressed. Such studies provide information on the significance of functional groups on the drug molecule which can be modified for optimum partitioning in drug delivery vehicles to account for effective target oriented release.

Interactions of Cetyltrimethylammonium Bromide with 1,3-Dioxolane in Water: A Study of Viscosity and Volumetric Properties

Densities and viscosities of ternary mixtures containing cetyltrimethyl ammonium bromide (CTAB) in aqueous solution of 1,3-dioxolane have been measured at 5 K intervals from 298.15 to 313.15 K and at atmospheric pressure. The experimental results of viscosity and density have been analyzed by using Jones-Dole equation and Masson equation. The values of constants A and B of Jones-Dole equation have been interpreted in terms of solute-solute and solute-solvent interactions. The standard partial molar volume,Vφ 0 at infinite dilution were determined from Masson equations. The structure making/breaking capacity of solute is interpreted with the help of Helper equation. The positive value of Helper′s constant (∂2Vφ 0/∂T2)p and the negative value of dB/dT shows that CTAB in studied organic solvent predominantly acts as a structure-maker.

Hydration characteristics, structural effects and the taste quality of some polyhydroxy compounds in aqueous solutions of nicotinic acid (vitamin B3) at (288.15–318.15) K

Physicochemical properties elucidating the hydration characteristics and structural effects of polyhydroxy compounds in mixed aqueous solutions offer significant information for the growth of pharmaceutical and food industries. Consequently, standard partial molar volumes and isentropic compressibilities at infinite dilution of saccharides, their derivatives and sugar alcohols in (0.01, 0.05, 0.09 and 0.13) mol kg−1 nicotinic acid(aq) (vitamin B3) solutions have been investigated by experimental density and ultrasonic velocity with respect to temperature. Their transfer values, compressibility hydration numbers, apparent massic volumes and isentropic compressibilities have also been determined. These parameters are important to study the taste behavior of polyhydroxy compounds and intermolecular interactions occurring in ternary mixtures. UV absorption spectra of the studied polyhydroxy compounds have been recorded in 1 × 10−4 mol kg−1 nicotinic acid(aq) solutions. The comparison of present results has been made with the studies reported earlier in l-ascorbic acid, thiamine HCl and pyridoxine HCl.

Volumetric and ultraacoustic properties of sodium salts of ibuprofen/diclofenac drugs in aqueous and aqueous-β-cyclodextrin solution

Present paper reports the study of inclusion complex formation between two non-steroidal anti-inflammatory drugs namely sodium ibuprofen and diclofenac sodium in water and aqueous-β-cyclodextrin solutions through thermodynamic properties like the standard partial molar volumes and the standard partial molar compressibility at 303.15, 308.15 and 313.15 K and at atmospheric pressure. For this, the densities and ultrasonic velocities of ternary sodium ibuprofen/diclofenac-β-cyclodextrin-water mixtures were measured and used for the calculation of apparent molar volume (V2,ϕ) and apparent molar compressibility (κs,2,ϕ). The concentration dependence of apparent properties has been fitted to standard relations and corresponding the standard partial molar volume (V2o) and the standard partial molar compressibility (κs,2o) and respective solute-solute interaction parameters Sv and Sk were graphically determined. The standard transfer volumes (ΔtrV2o) and standard transfer compressibility (Δtrκs,2o) were also computed and these properties have been interpreted in terms of drug hydration, inclusion complex formation, and different interactions involved. The sign of Sv and Sk revealed the weakening of solute–solute interactions in presence of cosolute β-cyclodextrin. Solubilization of hydrophobic parts, expulsion of water from hydrophobic cavity of β-cyclodextrin and inclusion complex formation of these drugs with β-cyclodextrin has been confirmed from partial molar volume and transfer properties.

Viscosity–Composition Properties of Glycine and L-Alanine Solutions in Aqueous Solutions of Tributylmethylphosphonium Methylsulfate Ionic Liquid at 303–333 K

Densities and viscosities of glycine and L-alanine solutions in aqueous solutions of tributylmethylphosphonium methylsulfate were measured at 303–333 K under atmospheric pressure. These data were used to calculate apparent molar volume ( $${{\phi }_{V}}$$ ), standard partial molar volume ( $$\phi _{V}^{0}$$ ), standard isobaric partial molar expansibility ( $$\phi _{E}^{0}$$ ) and its temperature dependence, the viscosity B-coefficient and solvation number ( $${{S}_{n}}$$ ). Viscosity B-coefficients were used to calculate the free energies of activation of viscous flow. The results were discussed in terms of solute–solute and solute–solvent interactions on the basis of cosphere overlap model and transition state theory.

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.

Thermodynamic and transport properties of ionic liquids, 1-alkyl-3-methylimidazolium thiocyanate in the aqueous lithium halides solutions

Thiocyanate based ionic liquids, [RMIM][SCN], as fluorine free and low toxic were used effectively in different areas of resaerch. In this work, the thermodynamic and transport properties of aqueous solutions of the synthesized ionic liquids based on thiocyanate anion, [RMIM][SCN] (R = butyl, hexyl and octyl) have been investigated at T = (288.15–318.15) K. Also, effect of LiX (X = Cl−, Br−) salts on the investigated properties have been studied at T = 298.15 K. In this respect, density, speed of sound and viscosity of the solutions have been measured and these properties were used to calculate the apparent molar volume, Vφ, and apparent molar isentropic compressibility κφ. The properties were correlated with corresponding empirical relations to achieve standard partial molar volume, Vφ0, partial molar isentropic compressibility, κφ0, and viscosity B-coefficient. These parameters were used to analysis of the interactions between components. In order to separate Vφ0 contributions of the ILs in binary solutions, the scaled particle theory was used at T = (288.15–318.15) K. The results show that the hydrophobic hydration interactions are dominant interactions.

Thermophysical properties of choline chloride/urea deep eutectic solvent in aqueous solution at infinite dilution at T = 293.15–323.15 K

The green solvents called deep eutectic solvents (DESs) have been investigated in numerous technologies in the recent years. In this study, for the first time it was attempted to measure thermophysical properties of commonly used DES (choline chloride/urea) in aqueous solutions at dilution concentration ranges of DES (x1 = 0.0000–0.0182) mole fraction and at T = 293.15–323.15 K. Some of the properties including density, speed of sound, refractive index and viscosity were measured for calculation of some thermophysical properties including standard partial molar volume ($$V_{{\upvarphi }}^{0}$$), partial molar isentropic compressibility ($$\kappa_{{\upvarphi }}^{0}$$), excess molar volume (VE), viscosity B-coefficient and molar refraction (RD) in dilute region of concentration. The obtained values of above-mentioned properties were used for evaluation of the solute–solvent interaction of the studied binary mixtures (DES + water).

Molecular interactions between some amino acids and a pharmaceutically active ionic liquid domiphen DL-mandelic acid in aqueous medium at temperatures from 293.15 K to 313.15 K

Molecular interactions between some amino acids (glycine, l-alanine, l-valine and l-leucine) and a pharmaceutically active ionic liquid domiphen DL-mandelic acid ([DOM][MAN]) in aqueous solution at various temperatures have been studied by means of volumetric, conductivity and spectroscopy measurements. Density data were used to derive standard partial molar volume, V2,φ0 standard partial molar expansibility, Eφ0, standard transfer volume, ΔtV0, isobaric thermal expansion coefficient, α0 and hydration number, nH of amino acids. On the basis of the experimental conductivity and fluorescence spectroscopy data, the aggregation behaviour of [DOM][MAN] in aqueous amino acid solutions was investigated. Critical micelle concentration, cmc, aggregation number, Nagg, some thermodynamic functions, ΔGm0, ΔHm0, ΔSm0 and ΔCp0 of micellization for [DOM][MAN] have been obtained. Effect of concentration and temperature on the obtained parameters has been discussed. Binding constant Kb for amino acid-[DOM][MAN] complex estimated using the UV–vis spectroscopic data approved that the solute-solvent interactions were strengthened by elevating the size of alkyl part of amino acids.

Modulation of molecular interactions of homologous series of amino acids with (sorbitol + glycine betaine) mixture compared to individual osmolytes: Thermodynamic analysis

Sorbitol and glycine betaine (GB) are the important osmolytes which are known to stabilize proteins. To understand the conformational stability of these complex biomolecules and their interactions with solvents in fine details, physico-chemical properties of the homologous series of amino acids were studied. The values of densities (ρ) and speeds of sound (u) of five amino acids: glycine, dl-alanine, dl-α-amino-n-butyric acid, l-valine, and l-leucine were measured in mixtures of {water + sorbitol (0.53 mol·kg−1) + glycine betaine (0.51 mol·kg−1)} and {water + sorbitol (1.12 mol·kg−1) + glycine betaine (1.04 mol·kg−1)} at T = 298.15 K. Heats of dilution (q) of amino acids from water to mixture {water + sorbitol (0.53 mol·kg−1) + glycine betaine (0.51 mol·kg−1)} solution were also measured. These values have been used to find the infinite dilution standard partial molar volume (V2.m0), standard partial molar adiabatic compressibility (Ks,2.m0), enthalpy of dilution (ΔdilH0), standard partial molar volume of transfer (ΔtrV2,m0) and hydration number of amino acids. By linear regression fitting of V2.m0,contributions of zwitterionic and hydrophobic groups of amino acids have been calculated. All these results have been correlated and interpreted in terms of intermolecular interactions on the basis of co-sphere overlap model. In case of all the amino acids except valine and leucine, the dominance of ionic–ionic and hydrophilic–ionic interaction is indicated. The values of (ΔtrΔdilH0) obtained by isothermal titration calorimetry support the volumetric interpretations. An attempt has also been made to find the calorimetric evidences to preferential hydration of lysozyme and preferential exclusion of osmolytes.

Heat Capacity and Volume Properties of Ammonium Thiocyanate in N-Methylpyrrolidone Solution at 298.15 K

The heat capacity and volumetric properties of ammonium thiocyanate solutions in N-methylpyrrolidone are measured at 298.15 K by calorimetric and densimetric means. Concentration dependences of the partial and apparent molar heat capacities and volumes of the investigated systems are discussed. The standard partial molar heat capacity and volume of NH4CNS, and the standard heat capacity and volume of ammonium and thiocyanate ions in N-methylpyrrolidone at 298.15 K are calculated.

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 approach to the interaction of L-Proline in aqueous Metformin Hydrochloride solutions for temperature range 298.15–318.15 K

Densities ρ, have been measured for l-Proline in aqueous Metformin Hydrochloride solutions of (0.05, 0.10, 0.15 and 0.20 M) mol kg−1 at T = 298.15–318.15 K. Apparent molal volumes Vφ have been determined from the experimental densities. These data have been used to calculate several thermodynamical parameters such as standard partial molal volume Vφ0, transfer volume ΔtrVφ0, hydration number nH, the second derivative of infinite dilution of partial molal volume with respect to temperature, viz., ∂2Vφ0/∂T2. Furthermore apparent molar expansibility E0, thermal expansion coefficient, α2 and the pair and triplet interaction coefficient have been calculated and reported. These results interpreted through a co-sphere overlap model indicate the presence of strong solute-co-solute interactions in the reported systems.