Molar Isentropic Compression Of Transfer Research Articles

New insight into molecular interactions of surface-active ionic liquid (SAIL) with some biomolecules: Experimental and computational approaches

Understanding the influence of ionic liquids (ILs) on the solubility of biomolecules in aqueous solutions is crucial for designing and optimizing novel biotechnological processes. However, the molecular-level mechanisms underlying this influence remain inconclusive and not fully elucidated. To contribute toward the understanding of molecular interactions between amino acids and ionic liquid in aqueous media, measurements of the densities and speeds of sound for L-serine and glycyl-L-serine in (0.00, 0.005, 0.01, 0.03, and 0.05) mol·kg−1 aqueous solutions of 1-octyl-3-methylimidazolium bromide were conducted at T = (288.15, 298.15, 308.15, and 318.15) K. From experimental data various thermodynamics paramours such as apparent molar volume (Vϕ), the partial molar volume (Vϕ0), standard partial molar volumes of transfer (ΔVϕ0) partial molar isentropic compression (Kϕ,s) and partial molar isentropic compression of transfer (ΔKϕ,S0) have been examined. Along with experiment results, computational tools were also utilized for a deeper understanding of the molecular changes. From density functional theory (DFT), the highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) were calculated and utilized to obtain molecular descriptors such as ionization energy (I), electron affinity (A), hardness (η), softness (S), chemical potential (μ), and electronegativity (χ). Thermochemical properties, including change in enthalpy (ΔH), and change in Gibbs free energy (ΔG), were predicted. Molecular docking studies were used to analysis the molecular interaction of ionic liquid with I-Motif structure and structural changes.

Acoustic and spectroscopic characterization of glycol ethers in vitamin B7 over the range of temperatures (288.15, 293.15, 298.15, 303.15) K

Density (ρ) and ultrasonic speed (u) of butoxyethanol and phenoxyethanol in aqueous solution of biotin concentrations (0.0012, 0.0017, 0.0022) mol·kg−1 at varying temperature range (288.15, 293.15, 298.15 and 303.15) K at 0.1 MPa were measured using Anton Paar DSA 5000 M. The volumetric and acoustical properties such as apparent molar properties (V∅), partial molar volume (V∅0),partial molar volume of transfer (ΔV∅0),apparent molar isentropic compression (K∅),partial molar isentropic compression (K∅0),partial molar isentropic compression of transfer are computed using the experimental data of density (ρ) and ultrasonic speed (u). This investigation is useful to understand the solvation behavior of biotin. Additionally, partial molar expansibilities (E∅0) along with their first order derivatives (∂E∅0/∂T)pare determined using the obtained experimental data. These results are effective in understanding the nature of interaction occurring inside the solution. Further, pair and triplet coefficients are evaluated which determines the structure making and breaking ability of glycol ethers in aqueous solution of biotin. Also, spectroscopic study of solutions is mentioned in current research which reveals the nature and strength of bond formation and various interactions in the mixture. The present study suggests the molecular interaction between the solute and solvent present in aqueous solution of Biotin (Vitamin B7) as solvent, butoxyethanol (BE) and phenoxyethanol (PE) as solute.

Effect of Additive (1-Butyl-1-methyl Pyrrolidinium Tetrafluoroborate) on Volumetric, Acoustic and Conductance Properties of Binary Aqueous Solutions of Benzylamine at T = (288.15, 298.15, 308.15, 318.15) K

Effect of additive, 1-butyl-1-methyl pyrrolidinium tetrafluoroborate [BmPyrr+][BF4–] on the volumetric, acoustic and conductance properties of binary aqueous solution of benzylamine has been analyzed at equidistant temperature range using different techniques. Using density and speed of sound data, volumetric and acoustic parameters like apparent and partial molar volumes (Vφ and Vφ0), apparent and partial molar isentropic compressions (Kφ,S and K0φ,S), partial molar volume of transfer and partial molar isentropic compression of transfer (ΔVφ0 and ΔK0φ,S) have been calculated. Conductance parameters like molar conductance (Λm), limiting molar conductance (Λ°m) and activation energy are also calculated using conductance data. All these parameters were used to analyze various types of interactions present in the system. Furthermore, density functional theory (DFT) calculations were conducted for comprehensive understanding of structural variations of ion pairs affecting their physical properties. The hydrogen bond formation in the mixture components was examined by using IR spectrum. Both DFT and Hartee-Fock (HF) methods were used to analyze the results. In addition, the DFT/B3LYP-D3 calculations were also carried out to gather data on the molecular geometry, interactions and other molecular characteristics of the ionic liquid under study.

Thermo-acoustic properties of monosaccharides D(−)-ribose and D(+)-xylose in aqueous diammonium hydrogen phosphate solutions at different temperatures

The volumetric and acoustic properties are used for investigating the interactions of polyhydroxy solutes D(−)-ribose and D(+)-xylose in different concentrations of diammonium hydrogen phosphate (DAP) solutions. Densities and speeds of sound of D(−)-ribose and D(+)-xylose in aqueous diammonium hydrogen phosphate (DAP) solutions have been measured over a temperature range of (298.15–318.15) K and at experimental pressure p = 0.1 MPa. Different parameters viz apparent molar volumes, Vϕ, partial molar volumes, apparent molar isentropic compression, partial molar isentropic compression, partial molar volume of transfer and molar isentropic compression of transfer are obtained using experimental density and ultrasonic speed data. The calculated parameters are discussed in rapports of solute–solvent interactions in solutions indicated the presence of ion-ion, ion-polar, hydrophilic-hydrophilic and hydrophobic–hydrophobic interactions in these ternary solutions, which was also confirmed from obtained positive values of apparent molar volume and negative values of apparent molar isentropic compressibility. Pair (VAB, KAB) and triplet (VABB, KABB) interaction coefficients determined by means of McMillan-Mayer theory are used to acquire valuable information about the dominance of pairwise interactions in the studied mixtures.

Volumetric-acoustic study of Disodium Ethylenediaminetetraacetic acid with Propylene and Hexylene glycol at different temperatures

The present study shows the molecular interactions at constant pressure of 0.1 megapascals (MPa) and a range of temperatures from (288.15, 298.15, 308.15, 318.15 K) in aqueous solution of Disodium EDTA in (0.01, 0.02, 0.03) mol.kg-1 along with Propylene glycol and Hexylene glycol. Speed of sound and density data is determined using Anton Paar DSA 5000 M. Various thermo-acoustic parameters are calculated using the obtained data. Experimental density values determined apparent Molar Volume (Vϕ), Partial Molar Volume (Vϕ°) as well as Partial Molar Volume of Transfer (ΔVϕ°) along with Partial Molar Expansibility (Eϕ°) and thermal expansion coefficient (α). While speed of sound determined the Apparent Molar Isentropic Compression (Kϕ,S), Partial Molar Isentropic Compression (Kϕ,S°) as well as Partial Molar Isentropic Compression of Transfer (ΔKϕ.S°). Pair and Triplet Coefficients along with Empirical constants have also been estimated. FTIR spectroscopic research had been carried out in the binary mixture. From propylene through hexylene glycols, these factors provide data related to significant interactions between solute and solvent.

Viscometric, ultrasonic and FTIR approach of streptomycin sulphate in the aqueous medium of K3Cit and Na3Cit at various temperatures: A Drug-Drug intermolecular interaction study

The effect of electrolyte on antibiotic drug streptomycin sulfate has been investigated at five temperatures (298.15–318.15) K and 0.1 MPa atmospheric pressure. The influence of concentrations and temperatures on the viscometric and ultrasonic properties of K3Cit and Na3Cit with water has been studied. The experimentally obtained data of ultrasonic speed (u) and viscosity (η) of the solutions have been used to evaluate different parameters at the studied temperatures. A, called the Falkenhagen coefficient, and B, is the Jones-Dole coefficient, transfer viscosity B-Coefficient, ΔtrB, at various temperatures (298.15–318.15) K were assessed by viscosity data. The ultrasonic data and the parameter for instance apparent molar isentropic compressibility,Kϕ,S, limiting apparent molar isentropic compressibility,Kϕ,S0, and limiting apparent molar isentropic compressibility of transfer, ΔtrKϕ,S0 have been analysed to study the presence of molecular interactions at different temperatures. The spectroscopic data have been used to know the existence of Hydrogen-bonding and other types of solute and solvent interactions in the solution. All these parameters have been taken to observe the different forces of attraction, association, dissociation, and structure-making/breaking properties of the drug streptomycin sulphate in the K3Cit + Water and Na3Cit + Water solutions at said temperatures.

Investigating the Solvation Behavior of Some Lithium Salts in Binary Aqueous Mixtures of 1-Ethyl-3-methylimidazolium Tetrafluoroborate ([EMIM][BF4]) at Equidistant Temperatures (T= 298.15, 303.15, 308.15, 313.15, 318.15) K

In the current work, measurements of density, as well as speed of sound, were made to analyze the solvation behavior of some lithium salts in binary aqueous mixtures of 1-ethyl-3-methylimidazolium tetrafluoroborate ([EMIM][BF4]) at equidistant temperatures (T = 298.15, 303.15, 308.15, 313.15, 318.15) K and a pressure of 0.1 MPa. Various thermo-physical parameters like apparent and partial molar volumes (VØ and VØ0), apparent and partial molar isentropic compressions (KØ, S and KØ, S0), partial molar volume, and partial molar isentropic compression of transfer (ΔVØ0 and ΔKØ, S0) were calculated from the experimental data. McMillan–Mayer theory was used to calculate pairwise (AB) and triplet interactions (ABB) from the calculated coefficients. Based on the calculated parameters, the presence and paramountcy of solute-solvent synergy particularly hydrophilic interactions over hydrophobic interactions have been found for both LiClO4 and LiI in binary aqueous mixtures of [EMIM][BF4]. Furthermore, Hepler’s criterion has been employed to examine the potential of these salts as a structure maker/breaker.

Evolution of solute–solvent interactions for aqueous 1-decyl-3-methylimidazolium bromide, [C10mim] [Br] solutions containing glycine/ glycylglycine through volumetric and acoustic studies

• New experimental density and speed of sound data have been collected. • Glycine/glycylglycine thermodynamic properties behaviour in aqueous IL has been examined. • Pair and Triplet interaction coefficient define the solute solvent interactions • The potential of co-solute to make and break structures has been interpreted. Volumetric and compressibility characteristics of ternary systems have been examined at temperatures T = 288.15 K−318.15 K at interval of 10 K and atmospheric pressure using vibrating tube densitometer DSA 5000 in order to investigate the interactions present in aqueous {glycine/glycylglycine + ionic liquid 1-decyl-3-methylimidazolium bromide} solutions. Using the experimental data for density, partial molar volume of transfer ( Δ V ϕ 0 ), limiting apparent molar volume ( V ϕ 0 ) have been computed. On the other hand speed of sound data utilized to calculate partial molar isentropic compression of transfer ( Δ K ϕ , S 0 ) and limiting apparent molar isentropic compression ( K ϕ , s 0 ). The ternary system's apparent molar and partially molar volumetric characteristics show that solute-solvent interactions prevail. The pair and triplet interaction coefficients determined from partial molar volumes of transfer and partial molar isentropic compression of transfer provide an explanation for the dominance of paired interactions.

Solvation properties of 1-butyl 2, 3-dimethyl imidazolium chloride ionic liquid in aqueous and aqueous glycine solutions at different temperatures using volumetric and compressibility parameters

Volumetric and compressibility approaches were employed in this investigation to analyse the intermolecular interactions of 1-Butyl-2,3-dimethyl imidazolium chloride in aqueous, in 0.05 mol.kg−1 aqueous glycine and 0.1095 mol.kg−1 aqueous glycine solutions over the concentration range 0.01 to 0.13 mol.kg−1 at different temperatures i.e., T= (288.15,293.15, 298.15, 303.15, 308.15, 313.15 and 318.15) K and atmospheric pressure by measuring density(ρ) and speed of sound(u) data. Various thermophysical parameters such as apparent molar volume of solute(Vϕ), limiting apparent molar volume of solute(Vϕ0), transfer limiting apparent molar volume of soluteΔtrVϕ0, Hepler's constant (∂2Vϕ0/∂T2), isentropic compressibility (κS), apparent molar isentropic compression of solute (KS,ϕ), partial molar isentropic compression of solute(KS,ϕ0) and partial molar isentropic compression of transfer of solute ΔtrKS,ϕ0 have been calculated using the corresponding thermophysical data at studied temperatures. In addition, the temperature dependence of apparent molar volume of solute has been used to determine isobaric expansivity or thermal expansion coefficient(α), apparent molar expansivity of solute Eϕ and limiting apparent molar expansivity solute Eϕ0 parameters of binary and ternary systems. The findings were described in terms of solute–solute and solute–solvent interactions.

Volumetric and acoustic studies of L-Citrulline in aqueous Urea and Dextrose solutions at different temperatures

Density (ρ) and speed of sound (u) values of L-Citrulline in aqueous solution, 0.06 mol·kg−1 aqueous Urea and aqueous 0.06 mol·kg−1 Dextrose solutions have been measured at T = (288.15, 293.15, 298.15, 303.15, 308.15, 313.15 and 318.15) K within the concentration range of (0.02 to 0.2) mol·kg−1.These measurements have been performed to evaluate some important parameters, viz, apparent molar volume of solute (Vϕ), limiting apparent molar volume of solute (Vϕ0), limiting apparent molar volume of transfer (ΔtrVϕ0), limiting apparent molar expansivity(Eϕ0), thermal expansion coefficient (α*), Hepler's constant (∂2Vϕ0∂T2), isentropic compressibility (κs), apparent molar compressibility (Ks,ϕ), limiting apparent molar compressibility (Ks,ϕ0), limiting apparent molar isentropic compressibility of transfer (ΔtrKs,ϕ0)and hydration number(ηH) . The results have been interpreted in terms of different interactions taking place in aqueous solutions.

Study of the interactions of monosaccharides D(+)-glucose and D(−)-fructose in aqueous diammonium hydrogen phosphate over the temperature range T=(288.15–318.15) K

The interactions of monosaccharides D(+)-glucose and D(−)-fructose in aqueous solutions of diammonium hydrogen phosphate (DAP) as a function of temperature have been investigated. The values of densities and speeds of sound have been measured for the system of monosaccharides and salt in aqueous solution. Densities and speed of sound for D(+)-glucose and D(−)-fructose in (0.5, 1.0, 1.5 and 2.0) mol⋅kg−1 aqueous solutions of diammonium hydrogen phosphate (DAP) are measured at T = (288.15, 298.15, 308.15 and 318.15) K and experimental pressure p = 0.1 MPa. The apparent molar volume,Vφ the partial molar volume, VφO and standard partial molar volumes of transfer, Δ VφO for D(+)-glucose and D(−)-fructose in aqueous solutions of diammonium hydrogen phosphate (DAP) have been calculated from density data. Apparent molar isentropic compression,Kϕ,s partial molar isentropic compression, Kϕ,so and partial molar isentropic compression of transfer, ΔKϕ,so have been calculated from speed of sound measurements. The expansibility parameter (∂Vϕ0 /∂T)p and its derivative (∂2 Vϕ0 /∂2 T)p along with pair (VAB, KAB) and triplet (VABB, KABB) interaction coefficients have also been calculated. The results have been interpreted in terms of solute − solute and solute–solvent interactions prevailing in these ternary systems.

Volumetric and acoustic properties of L-phenyl glycine and L-phenylalanine in aqueous solution of 1-dodecyl-3-methylimidazolium bromide [C12mim] [Br

To study the molecular interactions between the ternary mixtures containing long chain imidazolium based ionic liquid as a common solvent with substituted amino acids L-phenyl glycine and L-phenylalanine respectively, densities and speed of sound have been measured at three different temperatures viz. T = 288.15 K, 298.15 K, 318.15 and 318.15 K under 0.1 MPa pressure. The density and speed of sound data have been further utilized to calculate the apparent molar volume and apparent molar isentropic compression. From the data obtained, apparent molar volume (Vϕ), partial molar volume (Vϕ0), and standard partial molar volumes of transfer (ΔVϕ0). Positive values of apparent molar volume indicate strong interactions. Also, partial molar isentropic compression of transfer (ΔKϕ,S0) and partial molar isentropic compression (Kϕ,s) have been calculated from the sound of speed. Furthermore, structure making and structure breaking ability of solute have been discussed by evaluation of apparent molar expansivity, (ϕE0), Hepler's constant values ∂/∂Tp. The obtained results have been discussed in terms of solvation behavior, structural changes and various interactions present in different ternary mixtures (1-dodecyl-3-methylimidazolium bromide + amino acids + water).

Effect of trisodium citrate dihydrate on thermophysical properties of saccharides in aqueous media at different temperatures: Volumetric and acoustic properties

From the measurements of density, (ρ) and speed of sound, (u), the intermolecular interactions of D-maltose monohydrate and D-lactose monohydrate with trisodium citrate (TSC) have been explored in aqueous medium at temperatures, T = (293.15–313.15) K, pressure p = 0.1 MPa. From the experimental density measurements, apparent molar volume (VΦ), limiting apparent molar volume (VoΦ) and limiting apparent molar volume of transfer (VoΦ,tr) have been determined for various solutions of maltose and lactose in aqueous TSC. In addition, using experimental speed of sound data, apparent molar isentropic compressibility (KΦ,s), limiting apparent molar isentropic compressibility (KoΦ,s) and partial molar isentropic compression of transfer (KoΦ,s,tr) have been calculated.Further, apparent molar expansibility (EoΦ), Hepler's constant values(∂EoΦ∂T)Pand hydration number (nH)have been assessed to contribute the interpretations received from the acoustic and analysis. The assessed outcomes were construed in terms of diverse intermolecular interactions present in the ternary systems (saccharides+ water + TSC) through a co-sphere overlap model. From the Hepler's constant structure breaking nature of the solute have been confirmed.

Volumetric, acoustic and viscometric studies of solute-solute and solute-solvent interactions of glycine and its peptides in aqueous solutions of an antidepressant drug at different temperatures

From the density (ρ), speed of sound (u) and viscosity (η) measurements, the interactions of glycine, glycylglycine and glycylglycylglycine with antidepressant drug, nortriptyline hydrochloride have been investigated in aqueous medium at temperatures, T = (293.15–313.15) K and experimental pressure p = 0.1 MPa. From the experimental density measurements, apparent molar volume (VΦ), limiting apparent molar volume (VoΦ) and partial molar volumes of transfer (VoΦ,tr) have been determined for various solutions of glycine, glycylglycine and glycylglycylglycine in aqueous nortriptyline hydrochloride. In addition, using speed of sound data, apparent molar isentropic compression (Ks,Φ), limiting apparent molar isentropic compression (Kos,Φ) and partial molar isentropic compression of transfer (Kos,Φ,tr) have been calculated. Pair and triplet interaction coefficients are also determined from VoΦ,tr values using McMillan-Mayer theory. Further, apparent molar expansibility (EoΦ) and Hepler's constant values ∂EoΦ∂TP have been evaluated to assist the interpretations earned from the volumetric and acoustic analysis. The viscosity coefficients A and B, viscosity B-coefficient of transfer (Btr) and temperature derivative of B-coefficients (dB/dT) have been determined from viscosity data. The results were interpreted in terms of different kinds of intermolecular interactions present in the ternary systems (amino acid/peptides + water + nortriptyline hydrochloride) through a cosphere overlap model. The Hepler’s constant and temperature derivative of B-coefficients (dB/dT) confirms the structure breaking nature of the solute.

Volumetric and acoustic studies of aqueous l-arginine·HCl and l-proline in electrolytic and non-electrolytic solutions at various temperatures

Densities and speed of sound of l-arginine hydrochloride and l-proline within the concentration range (0.03–0.2) mol.kg−1 in water and in aqueous NaCl and Urea are determined between temperatures 288.15 K and 318.15 K and at one atmospheric pressure. Densities and speeds of sound have been used to calculate apparent molar volume of solute (Vφ), isentropic compressibility of solution (κS), apparent molar isentropic compressibility (KS,φ) of solute, limiting apparent molar volume (Vφ0), limiting apparent molar volume of transfer (ΔtrVφ0), limiting apparent molar expansibility (Eφ0), limiting apparent molar isentropic compressibility (KS,φ0) and limiting apparent molar isentropic compressibility of transfer (ΔtrKS,φ0). These results are then interpreted in terms of intermolecular interactions. The concentration dependencies of the calculated quantities, their limiting values and temperature characteristics are discussed in terms of solute - solvent and solute - solute interactions at experimental conditions.

Thermophysical properties of amino acids L-serine and L-leucine in aqueous diammonium hydrogen phosphate solutions: Volumetric and acoustic studies

Densities and speeds of sound measurements have been done for the amino acids (AAs) L-serine and L-leucine in aqueous diammonium hydrogen phosphate (DAP) solution at different temperatures with a specific interval of temperature. Thermophysical parameters including apparent molar volume (Vϕ), partial molar volume (Vϕ0), apparent molar isentropic compression (Kϕ,s), partial molar isentropic compression (Kϕ,s0) and transfer volumes like partial molar volumes of transfer (ΔVϕ0) and partial molar isentropic compression of transfer (ΔKϕ,so) were determined using the measured experimental data. The co-sphere overlap model was used to interpret the sort of interactions dominating in the system. The obtained transfer quantities are positive which indicates the dominance of ion-hydrophilic and hydrophilic–hydrophilic interactions existing among the amino acids and diammonium hydrogen phosphate salt solution in aqueous medium. Pair and triple interaction coefficients calculated for the system of amino acids and phosphate salt in aqueous medium. Overall results have been elaborated in terms of the solute-solvent or solute-solute interactions prevailing in the system.

Interaction studies of diglycine with aqueous solutions of sulphathiazole drug at different temperatures

The interactions of diglycine with sulphathiazole drug as a function of temperatures have been studied using volumetric and acoustic parameters. Densities and speeds of sound of diglycine in (0.001, 0.002,0.005, and 0.010) mol·kg-1 aqueous solutions of sulphathiazole drug have been measured at five different temperatures of (288.15,293.15,298.15,303.15 and 308.15) K under 0.1MPa pressure. From density data, the apparent molar volume (Vf), the partial molar volume ( ) and the standard partial molar volume of transfer ( ) for glycine from water to aqueous sulphathiazole solutions have been calculated. Partial molar isentropic compression and partial molar isentropic compression of transfer ( ) have been calculated from the speed of sound data. Transfer parameters by using cosphere overlap model have been explained from the point of view of concentration dependence of solute-solute and solute-solvent interactions. To draw the conclusion from the volumetric and acoustic data, limiting apparent molar expansion , as well as hydration numbers, have been studied. The calculated values of thermal expansion coefficient, , have small and positive values. All of these derived or calculated parameters are explained to understand the solvation behavior, mixing aspects and various types of interactions born in the ternary solutions of (drug + water + dipeptide) due to change in structure. We have also attempted to examine the temperature and concentration dependence of such interactions.

Effect of choline chloride based deep eutectic solvents on lithium perchlorate + propylene carbonate solutions: Thermodynamic, transport, electrochemical and computational study

BackgroundThe influence of deep eutectic solvents (DESs) {(choline chloride (ChCl): lactic acid (LA) and choline chloride: malonic acid (MA)} with different mass fractions of DES on the thermodynamic, transport and electrochemical properties of lithium perchlorate (LiClO4) in propylene carbonate (PC) systems were studied. These investigations are in line with proposing new green electrolyte solutions for future electrochemical applications. MethodsDensity, speed of sound and viscosity at T = 288.15–318.15 K of (LiClO4 + PC + DESs) solutions have been measured from which the apparent molar volume, apparent molar isentropic compressibility, standard partial molar volume, partial molar isentropic compressibility, partial molar volumes of transfer, partial molar isentropic compressibility of transfer and viscosity B-coefficient were calculated. Also density functional theory (DFT) of LiClO4 with DESs in PC solvent was applied. As well as linear sweep voltammetry (LSV) measurements were performed. Significant findingsThe calculated thermodynamic and transport parameters indicated that interactions of ChCl/LA with LiClO4 in the presence of PC are more favorable than ChCl/MA. Then, the DFT was applied to find further evidence for these solute-solvent interactions and confirmed the thermodynamic and transport results. Finally, LSV measurements were performed for investigating the electrochemical potential windows of the systems.

Molecular Interactions of Diphenhydramine-hydrochloride with Some Imidazolium-Based Ionic Liquids in Aqueous Media at T = 293.15-313.15 K: Volumetric, Acoustic, and UV Absorption Studies.

From the density (ρ) and speed-of-sound (u) measurements, the interactions of the drug diphenhydramine-hydrochloride (DPH) with three imidazolium-based ionic liquids (ILs) (1-butyl-3-methylimidazolium chloride, [C4mim][Cl], 1-hexyl-3-methylimidazolium chloride1, [C6mim][Cl], and 1-methyl-3-octylimidazolium chloride, [C8mim][Cl]) have been investigated in aqueous medium at T = 293.15–313.15 K and experimental pressure p = 0.1 MPa. From the density calculations, the apparent molar volume (Vϕ) and the apparent partial molar volumes of transfer (ΔtVϕo) have been determined for various solutions of DPH in aqueous solutions of different ILs. In addition, from the speed-of-sound data, the apparent molar isentropic compressibility (Kϕ), apparent partial molar isentropic compressibility (Kϕo), and apparent partial molar isentropic compressibility of transfer (ΔtKϕο) have been calculated. The pair and triplet interaction coefficients are derived from apparent partial molar volumes of transfer. For the present mixtures, the absorption spectra have been also recorded using a UV–visible spectrophotometer. Using Hepler’s constant, the structure-making nature of the solute has been confirmed. All these calculated parameters provide detailed insights into various physicochemical interactions prevailing in the ternary system and confirm the presence of a strong attractive interaction between DPH and ILs.

Effect of ethylene glycol/diethylene glycol/triethylene glycol on the thermodynamics of the aqueous biotin solutions at various temperatures

Acoustic and volumetric parameters for the liquid mixture (water + Biotin + ethylene glycol/diethylene glycol/triethylene glycol) are evaluated at different temperatures (288.15 K, 298.15 K, 308.15 K, and 318.15 K) and constant pressure of 0.1 MPa over the range of biotin concentrations (0.0000, 0.0015, 0.0025, and 0.0035) mol·Kg-1. The experimental work was carried out by Anton Paar DSA 5000 M, where the density (ρ) and the speed of sound (c) are measured, which are later used to determine the various derived thermodynamic properties, such as, apparent molar properties (apparent molar volume, Vϕ; apparent molar isentropic compression,Kϕ,S), the partial molar properties (partial molar volume, Vϕ0; partial molar isentropic compression, Kϕ,S0), the partial molar transfer properties (partial molar volume of transfer, ΔVϕ0; partial molar isentropic compression of transfer, ΔKϕ,S0) and the partial molar expansibility (Eϕ0) along with its first derivative ∂Eϕ0/∂TP. The obtained results are explained in terms of the kind of intermolecular interactions developed in the mixture using the co-sphere overlap model. Further, with the partial molar properties, the pair and triplet interaction coefficients (VAB,KAB; VABB, KABB) are calculated.