Standard Partial Molar Volumes Research Articles

Volumetric and UV Absorption Studies on Interactions of an Active Pharmaceutical Ingredient Ionic Liquid (API-IL) Domiphen l-Proline with Amino Acids and Glycyl Dipeptides in Aqueous Solution at T = (293.15–308.15) K

Novel ionic liquids containing the domiphen cation, as an active pharmaceutical ingredient ionic liquid (API-IL), domiphen l-proline ([DOM][l-PRO]) was synthesized and the interactions of domiphen l-proline with some small biomolecules (amino acids and glycyl dipeptides) were investigated at different temperatures from density and UV–Vis spectroscopy measurements. The apparent molar volumes, standard partial molar volumes, transfer volumes, hydration numbers and partial molar expansibilities of small biomolecules have been calculated. Group contributions of amino acids/dipeptides to the standard partial molar volume were determined and the contributions from the zwitterionic end group (NH3 +, COO−), CH2 and (CH2CONH) groups have been obtained. The binding constants between small biomolecules and [DOM][l-PRO] were also obtained. A detailed insight into the physicochemical interactions in the ternary systems was obtained through the perusal of these parameters. Compared with [DOM][Br], [DOM][l-PRO] interacts with small biomolecules weakly.

Standard partial molar heat capacities and volumes of aqueous N-methylpiperidine and N-methylpiperidinium chloride from 283 K to 393 K

Densities and volumetric heat capacities for dilute solutions of N-methylpiperidine (N-MP, 0.2mol·kg−1) and N-methylpiperidinium chloride (N-MPH+Cl−, 0.1mol·kg−1) were measured relative to water at 0.1MPa using a vibrating-tube densimeter, and at 0.4MPa using a twin fixed-cell, power-compensation, differential temperature-scanning nano calorimeter, over the temperature ranges 283.15K≤T≤363.15K and 283.15K≤T≤393.15K, respectively. The resulting apparent molar volumes, Vϕ, and heat capacities, Cp,ϕ, were corrected for speciation effects using Young’s rule and extrapolated to infinite dilution using the Debye-Hückel limiting law, Yo≈Yϕ−AYIs1/2, to yield the standard partial molar properties, Yo, for N-MP(aq) and N-MPH+Cl−(aq). The standard partial molar volumes, Vo, and heat capacities, Cpo, were represented by a semi-empirical function of solvent density and temperature, Yo(ρw,T), the “density” model, which can be used to extrapolate these results, as well as other thermodynamic properties for the ionization of N-methylpiperidine, to higher temperatures.

Solute-solvent interactions of amino acid l-phenylalanine in aqueous 1-butyl-2,3-dimethylimidazolium bromide ionic liquid solutions

Densities of l-phenylalanine in water and in aqueous1-butyl-2,3-dimethylimidazolium bromide solutions, at T=(283.15, 288.15, 293.15, 298.15 and 303.15)K and atmospheric pressure have been measured. The apparent molar volumes, VФ, standard partial molar volumes, VФ0, limiting apparent molar expansibilities, EФ0, and standard partial molar volumes of transfer, ΔVФ0, have been calculated. The values of ΔVФ0 are negative. These volumetric parameters are interpreted in terms of various mixing effects between l-phenylalanine and [BMMIm]Br in aqueous solution. The 1H NMR measurements of binary mixtures of l-phenylalanine and [BMMIm]Br in D2O solutions have been carried out to understand the possible interactions. The results show that the interactions between the hydrophobic-hydrophobic groups of [BMMIm]Br and l-phenylalanine may be dominant in the studied system. Furthermore, the density functional theory calculations provide stabilization energies and suggest possible interaction ways that support the volumetric and NMR measurements.

Solvation behavior and sweetness response of carbohydrates, their derivatives and sugar alcohols in thiamine HCl (vitamin B1) and pyridoxine HCl (vitamin B6) at different temperatures

Volumetric properties are important tools to study the solvation behavior of solutes and reveal valuable information about solute-solute/cosolute interactions. Therefore, standard partial molar volumes at infinite dilution have been calculated from density measurements for monosaccharides, their methoxy and deoxy derivatives, disaccharides and sugar alcohols in (0.05, 0.15, 0.25 and 0.35)molkg−1 thiamine HCl(aq) and pyridoxine HCl(aq) solutions over temperature range (288.15–318.15)K at pressure, p=0.1MPa. The corresponding transfer volumes, expansibilities and apparent massic volumes have been evaluated to examine the solvation behavior and the basic taste quality of studied solutes. UV–Vis absorption study of these solutes has also been carried out in 1.0×10−4molkg−1 thiamine HCl and pyridoxine HCl solutions. Results have been compared with our previously reported studies carried out in l-ascorbic acid (vitamin C). Stereochemical effects on hydration controlled by dominant conformations of studied solutes have also been discussed.

Thermodynamics of aqueous adenine: Standard partial molar volumes and heat capacities of adenine, adeninium chloride, and sodium adeninate from T = 283.15 K to 363.15 K

Apparent molar volumes, Vϕ, and apparent molar heat capacities, Cp,ϕ, were measured for aqueous solutions of neutral adenine (AdH) and adeninium chloride (AdH2Cl) at temperatures from 288.15K to 363.15K, and for sodium adeninate (NaAd) at temperatures from 283.15K to 313.15K. Density measurements used in the determination of the standard partial molar volume, Vo, were made with a vibrating-tube densimeter at ambient pressure. Heat capacity measurements used in the determination of the standard partial molar heat capacity, Cpo, were made with a twin fixed-cell, differential output, power compensating, temperature-scanning calorimeter at a pressure of 0.4MPa. The contributions from minor equilibrium species were removed using Young’s Rule to yield values for the standard partial molar volume and heat capacities of the ionic species AdH2+(aq) and Ad−(aq), and the equilibrium mixture of neutral species AdH∗(aq). Semi-empirical equations describing the temperature dependence of Vo and Cpo for each species were fitted by regression to the experimental results. From these equations, the standard partial molar volume change ΔrVom and heat capacity change ΔrCpom for the ionization reactions were calculated. The standard partial molar volumes presented in this study for neutral adenine are the first to be experimentally determined at temperatures above 330K, while the standard partial molar heat capacities are the first to be reported at temperatures above 298.15K. The experimental values for the adeninium cation and adeninate anion are the first to be reported in the literature.

Mode of action of betaine on some amino acids and globular proteins: Thermodynamic considerations

The interactions of the amino acids glycine, l-alanine, dl-α-amino-n-butyric acid, l-valine, and l-leucine have been studied based on values of apparent molar volume (V2,m,ϕ) and apparent molar compressibility (Ks,2,m,ϕ) in 1mol·kg−1 and 2mol·kg−1 aqueous betaine solutions at T=298.15K. These thermodynamic quantities have been calculated from density and sound velocity measurements. Isothermal titration calorimetry has been employed to determine the values of enthalpies of interaction of aqueous solutions of these amino acids with betaine. These data have been further used to calculate values of infinite dilution standard partial molar volumes (V2,mo), standard partial molar isentropic compressibilities (Ks,2,mo) and limiting enthalpies of dilution (ΔdilHmo) of these amino acids in aqueous betaine solutions. The standard partial molar volumes of transfer (ΔtrV2,mo), isentropic compressibilities of transfer (ΔtrKs,2,mo) and enthalpies of dilution of transfer Δtr(ΔdilHom) of amino acids from water to aqueous betaine solutions have been calculated from the measured data in order to understand possible intermolecular interactions such as ion-ion, ion-polar, hydrophilic-hydrophobic and hydrophobic-hydrophobic group interactions. The contributions of the end groups {(NH3+, COO−), CH2 groups and the other alkyl chains of the amino acids to V2,mo} have also been determined. The interactions of betaine with the globular proteins α-lactalbumin and bovine serum albumin have also been studied. Such studies are important in obtaining information on the action of osmolytes on proteins and their constituents and establishing possible correlations.

Solution Thermodynamics of N,N /-Ethylenebis-(salicylideneiminato)-diaquochromium(III) Chloride in Aqueous Dimethylsulphoxide

The densities, viscosities and refractive indices of N,N /-ethylene-bis(salicylideneiminato)-diaquochromium(III) chloride, [Cr(salen)(H2O)2]Cl, in aqueous dimethylsulfoxide (DMSO) with different mass fractions (w 2 = 0.20, 0.40, 0.60, 0.80 and 1.00) of DMSO were determined at 298.15, 308.15 and 318.15 K under atmospheric pressure. From measured densities, viscosities and refractive indices the apparent molar volumes (V φ ), standard partial molar volume (V φ 0 ), the slope (S V * ), standard isobaric partial molar expansibility (φ E 0 ) and its temperature dependence (∂φ E 0 /∂T) p , the viscosity B-coefficient, its temperature dependence (∂B/∂T), solvation number (S n ) and apparent molar refractivity (R D φ ), etc., were calculated and discussed on the basis of ion–ion and ion–solvent interactions. These results revealed that the solutions are characterized by ion–solvent interactions rather than by ion–ion interactions and the complex behaves as a long range structure maker. Thermodynamics of viscous flow was discussed in terms of transition state theory.

Study of solvation consequences of glycine, L-alanine and L-valine in aqueous 1-butyl-4-methyl pyridinium chloride ionic liquid solutions probed by physicochemical approach in the temperature interval (288.15–308.15) K

The apparent molar volume (V∅) and isentropic compression (K∅,s) of glycine, L-alanine and L-valine have been studied in (0.025, 0.05, 0.075 and 0.1)mol·kg−1 aqueous 1-butyl-4-methyl pyridinium chloride ([C4mpy]Cl) solutions over a range of temperatures (288.15, 293.15, 298.15, 303.15 and 308.15)K from the values of densities (ρ) and ultrasonic speed (c), repectively. The standard partial molar volumes (V∅0), standard partial molar isentropic compression (K∅,s0), and experimental slopes (SV and SK) have been determined for these amino acid solutions from the Masson equation and have been interpreted in terms of solute-solvent and solute-solute interactions, respectively. The hydrophilic-hydrophilic, hydrophilic-hydrophobic and hydrophobic-hydrophobic interactions are involved in the studied systems of [C4mpy]Cl+amino acids+H2O by calculating the corresponding transfer functions (ΔV∅0andΔK∅,s0). The contribution of the charged end groups (NH3+,COO-), (-CH2) group and other alkyl chains of the amino acids were estimated using V∅0 values. Hydration number (nH) for studied amino acids in aqueous [C4mpy]Cl solutions are positive, which suggest a strong dehydration effect of [C4mpy]Cl. The obtained parameters will be helpful to understand mixing effects and other complex biological processes between head and side chain group of amino acids and ionic liquid [C4mpy]Cl in aqueous solution.

Thermodynamic Difference between Protocatechualdehyde and p-Hydroxybenzaldehyde in Aqueous Sodium Chloride Solutions

The enthalpies of dilution of protocatechualdehyde and p-hydroxybenzaldehyde in the aqueous sodium chloride solutions were measured by using a mixing-flow microcalorimeter at 298.15 K. Densities of the ternary homogeneous systems at different temperatures (293.15, 298.15, 303.15, 308.15, and 313.15 K) were also measured with a quartz vibrating-tube densimeter. The homogeneous enthalpic interaction coefficients (h2, h3, and h4) were calculated according to the excess enthalpy concept based on the calorimetric data. The apparent molar volumes (Vϕ) and standard partial molar volumes (Vϕ0) of the investigated system were computed from their density data. The variation trends in h2 and Vϕ0 with increasing salt molality were obtained and discussed in terms of the (solute + solute) and (solute + solvent) interactions. The experimental results showed that the molecular structures of protocatechualdehyde and p-hydroxybenzaldehyde, especially the number of hydroxyl groups, have evident influence on their thermodynamic properties. The thermodynamic data obtained in this work may be helpful for exploring the structure–function relationship of protocatechualdehyde and p-hydroxybenzaldehyde.

Volumetric, Acoustic and Transport Properties of Metformin Hydrochloride Drug in Aqueous d-Glucose Solutions at T = (298.15–318.15) K

Apparent molar volumes, apparent molar adiabatic compressibilities and viscosity B-coefficients for metformin hydrochloride in aqueous d-glucose solutions were determined from solution densities, sound velocities and viscosities measured at T = (298.15–318.15) K and at pressure p = 101 kPa as a function of the metformin hydrochloride concentrations. The standard partial molar volumes ( $$ \phi_{V}^{0} $$ ) and slopes ( $$ S_{V}^{*} $$ ) obtained from the Masson equation were interpreted in terms of solute–solvent and solute–solute interactions, respectively. Solution viscosities were analyzed using the Jones–Dole equation and the viscosity A and B coefficients discussed in terms of solute–solute and solute–solvent interactions, respectively. Adiabatic compressibility ( $$ \beta_{s} $$ ) and apparent molar adiabatic compressibility ( $$ \phi_{\kappa }^{{}} $$ ), limiting apparent molar adiabatic compressibility ( $$ \phi_{\kappa }^{0} $$ ) and experimental slopes ( $$ S_{\kappa }^{*} $$ ) were determined from sound velocity data. The standard volume of transfer ( $$ \Delta_{t} \phi_{V}^{0} $$ ), viscosity B-coefficients of transfer ( $$ \Delta_{t} B $$ ) and limiting apparent molar adiabatic compressibility of transfer ( $$ \Delta_{t} \phi_{\kappa }^{0} $$ ) of metformin hydrochloride from water to aqueous glucose solutions were derived to understand various interactions in the ternary solutions. The activation parameters of viscous flow for the studied solutions were calculated using transition state theory. Hepler’s coefficient $$ (d\phi /dT)_{p} $$ indicated the structure making ability of metformin hydrochloride in the ternary solutions.

The study of solute–solvent interactions in the ternary {Amino acid (Glycine or l-serine) + ionic liquid (1-butyl-3-methylimidazolium tetra fluoroborate [Bmim][BF4]) + H2O} system at different temperatures and ambient pressure: Volumetric study

Abstract The solute–solvent interactions in the studied aqueous ternary systems containing some amino acids (Glycine or l -serine) and ionic liquid (1-butyl-3-methylimidazolium tetra fluoroborate [Bmim][BF4]) are studied by using the volumetric properties data. These properties contains: apparent molar volumes, standard partial molar volumes, limiting partial molar volumes of transfer, apparent molar expansibility and hydration number. Vφ values were increased when rising concentration of amino acids and also temperature while decreased by increasing concentration of ionic liquid. Apparent molar volumes of transfer, ΔVφ0, for studied amino acids from water to aqueous solutions of ionic liquid (IL) are calculated. The limiting partial molar volumes of transfer ΔtVφ0 values were negative. Results confirmed the dominance of hydrophobic-hydrophobic interactions in both ternary solutions.

What is the fundamental ion-specific series for anions and cations? Ion specificity in standard partial molar volumes of electrolytes and electrostriction in water and non-aqueous solvents.

The importance of electrolyte solutions cannot be overstated. Beyond the ionic strength of electrolyte solutions the specific nature of the ions present is vital in controlling a host of properties. Therefore ion specificity is fundamentally important in physical chemistry, engineering and biology. The observation that the strengths of the effect of ions often follows well established series suggests that a single predictive and quantitative description of specific-ion effects covering a wide range of systems is possible. Such a theory would revolutionise applications of physical chemistry from polymer precipitation to drug design. Current approaches to understanding specific-ion effects involve consideration of the ions themselves, the solvent and relevant interfaces and the interactions between them. Here we investigate the specific-ion effects trends of standard partial molar volumes and electrostrictive volumes of electrolytes in water and eleven non-aqueous solvents. We choose these measures as they relate to bulk properties at infinite dilution, therefore they are the simplest electrolyte systems. This is done to test the hypothesis that the ions alone exhibit a specific-ion effect series that is independent of the solvent and unrelated to surface properties. The specific-ion effects trends of standard partial molar volumes and normalised electrostrictive volumes examined in this work show a fundamental ion-specific series that is reproduced across the solvents, which is the Hofmeister series for anions and the reverse lyotropic series for cations, supporting the hypothesis. This outcome is important in demonstrating that ion specificity is observed at infinite dilution and demonstrates that the complexity observed in the manifestation of specific-ion effects in a very wide range of systems is due to perturbations of solvent, surfaces and concentration on the underlying fundamental series. This knowledge will guide a general understanding of specific-ion effects and assist in the development of a quantitative predictive theory of ion specificity.

Apparent molar volumes of aqueous solutions of sodium acetate and sodium benzoate at temperatures from 323 K to 573 K and pressure 10 MPa

Densities of aqueous solutions of sodium acetate and sodium benzoate have been measured at 50K intervals in the temperature range 323.15–573.15K at constant pressure p=10.0MPa by vibrating tube densimetry. The solute molalities ranged from 0.05 to 4.0mol·kg−1 (for sodium acetate) or 1.0mol·kg−1 (for sodium benzoate). The observed densities were used to calculate apparent molar volumes, which were fitted with an extended Redlich-Rosenfeld-Meyer-type equation to yield standard partial molar volumes of the solutes at infinite dilution. No direct comparisons with literature data were possible but the present results are broadly consistent with previous studies. This work greatly expands the database for the volumetric behaviour of both solutes at high temperatures. Despite the probable presence of anion hydrolysis the volumes of both salts show the steep decrease at high temperatures typical of simple 1:1 electrolytes. As expected, the acetate ion has a smaller volume than benzoate, with the difference increasing markedly with temperature, possibly reflecting the greater hydrophobicity of the benzoate ion. Combination of the present results with appropriate literature data enabled calculation of the volume change for the neutralization reaction: HX(aq)+NaOH(aq)→NaX(aq)+H2O. The values were similar for the two solutes and show a complex dependence on temperature.

Study of interactions of d(+)-glucose and d(−)-fructose with trilithium citrate in aqueous medium through volumetric and ultrasonic properties over the temperature range T = (288.15–318.15) K

The interactions of salt trilithium citrate (TLC) with saccharides d(+)-glucose and d(−)-fructose, have been investigated in aqueous medium from density (ρ) and speed of sound (c) measurements at T=(288.15–318.15) K and experimental pressure p=0.1MPa. The apparent molar volume (Vϕ), the partial molar volume (Vϕo) and standard partial molar volumes of transfer (ΔVϕo) for both saccharides, from water to aqueous trilithium citrate (TLC) have been calculated from density data. The limiting apparent molar expansibilities have also been calculated. The 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 results. The pair and triplet interaction coefficients have been calculated from partial molar volumes of transfer and partial molar isentropic compression of transfer. A detailed insight into the physicochemical interactions e.g. ion–hydrophilic, hydrophilic–hydrophilic and hydrophilic–hydrophobic interactions in the saccharide-salt system along with the structure-making/structure-breaking tendency of the saccharides, have been retrieved through the perusal of these calculated parameters.

Interactions of 1-butyl-2,3-dimethylimidazolium bromide ionic liquid with glycine, l-alanine and l-valine: A volumetric and NMR spectroscopic study

The densities of glycine, l-alanine and l-valine in aqueous and aqueous solutions of 1-butyl-2,3-dimethylimidazolium bromide [BMMIm]Br have been determined at (283.15, 288.15, 293.15, 298.15 and 303.15) K and atmospheric pressure. The apparent molar volumes, standard partial molar volumes, standard partial molar volume of transfer and hydration numbers have been calculated. The values of standard partial molar volume of transfer for three amino acids are negative at all temperatures studied. The values of standard partial molar volume of transfer become more negative with the increase of hydrophobicity of the amino acid side-chains. These volumetric parameters are interpreted in terms of various mixing effects between amino acids and [BMMIm]Br in aqueous solutions. Furthermore, the 1H NMR measurements of binary mixtures of amino acids and [BMMIm]Br dissolved in D2O have been carried out. The influence in electron density around the protons of [BMMIm]Br followed the order: l-valine>l-alanine>glycine. The results were interpreted on possible molecular interactions between the intrinsic hydrophilicity/hydrophobicity of amino acid side-chains and [BMMIm]Br.

Effect of tetrabutylammonium hydrogen sulphate on the Solution thermodynamics of thiamine hydrochloride in aqueous solutions

The densities and viscosities of thiamine hydrochloride (vitamin-B1) in aqueous tetrabutylammonium hydrogen sulphate (Bu4NHSO4) solutions with several molal concentrations (mBu4NHSO4=0.000, 0.005, 0.010, 0.015 and 0.020mol⋅kg‐1) of Bu4NHSO4 were determined at T=(298.15, 308.15 and 318.15) K under atmospheric pressure. Using experimental data apparent molar volume (φV), standard partial molar volume (φV0), the slope (SV), standard isobaric partial molar expansibility (φE0) and its temperature dependence(∂φE0/∂T)P, the viscosity B-coefficient and solvation number (Sn), etc., were determined. Viscosity B-coefficients were further utilized to obtain the free energies of activation of viscous flow per mole of the solvents (Δμ10≠) and of the solute (Δμ20≠). Effects of molality, solute structure and temperature on all these parameters were analyzed in term of ion-ion and ion-solvent interactions; results revealed that the solutions are characterized predominantly by ion-solvent interactions and thiamine hydrochloride behaves as a long-range structure maker.

Volumetric and viscometric behaviour of pyridoxine hydrochloride in aqueous tetrabutylammonium hydrogen sulphate solutions at different temperatures

Apparent molar volumes and viscosity B-coefficients for pyridoxine hydrochloride in aqueous tetrabutylammonium hydrogen sulphate (TBAHS) solutions were determined from solution density and viscosity measurements at T=(288.15–318.15)K and p=101kPa as a function of pyridoxine hydrochloride concentration. The standard partial molar volume and slopes, obtained from the Redlich-Meyer equation, have been interpreted in terms of solute-solvent and solute-solute interactions respectively. The viscosity data were analyzed using the Jones-Dole equation and the derived parameters A and B were interpreted in terms of solute-solute and solute-solvent interactions respectively. The standard volume of transfer and viscosity B-coefficients of transfer of pyridoxine hydrochloride from water to aqueous TBAHS solutions were derived to study various interactions in the ternary solutions. The activation parameters of viscous flow for the ternary solutions were also calculated and explained in terms of transition state theory.

Thermodynamics of (solute + solute) and (solute + solvent) interactions of homologous series of amino acids with thiamine hydrochloride in aqueous medium at T = (305.15, 310.15, 315.15) K: A volumetric and acoustic approach

Apparent molar volumes (Vϕ) and apparent molar isentropic compression (Kϕ,s) of glycine, l-alanine, l-valine and l-leucine in (0.05, 0.10, 0.15, 0.20)mol·kg−1 aqueous solution of thiamine hydrochloride (thiamine-HCl) have been determined at T=(305.15, 310.15 and 315.15)K and experimental pressure p=0.1MPa, from the density and speed of sound measurements. The partial molar volume Vϕo, standard partial molar volumes of transfer ΔVϕo for amino acids from water to aqueous thiamine-HCl, partial molar isentropic compression Kϕ,s and partial molar isentropic compression of transfer ΔKϕ,so have been calculated from the corresponding data. Group contributions of amino acids to partial molar volume are also determined. The pair and triplet interaction coefficients are obtained from partial molar volumes of transfer and partial molar isentropic compression of transfer. The partial molar expansibility (∂Vϕo/∂T)p, second order derivative (∂2Vϕo/∂T2)p have also been calculated. The parameters obtained have been used to explain the results in terms of (solute-solute)/(ion-ion), (solute-solvent) interactions, structure making and structure breaking behaviour of amino acids in aqueous thiamine-HCl solutions.

Intermolecular interactions of α-amino acids and glycyl dipeptides with the drug domiphen bromide in aqueous solutions analyzed by volumetric and UV–vis spectroscopy methods

The interactions of four α-amino acids and three glycyl dipeptides with drug domiphen bromide (DB) as the function of temperature and DB molality have been investigated by combination of volumetric and UV–vis spectroscopy methods. The standard partial molar volume (V2,ϕ∘), standard partial molar transfer volumes (ΔtVo), hydration number (nH), partial molar expansibility (Eϕ∘) and Hepler’s factor (∂2V2,ϕ∘/∂T2)p are calculated from the density data. The above parameters are used to interpret the solute-solvent interactions in ternary systems. The dependence of these parameters upon concentration, temperature and hydrocarbon chain length of the amino acids/dipeptides clearly suggest the roles of amino acids/dipeptides and domiphen bromide in solute-solvent interactions. Group contributions of amino acids/dipeptides to the standard partial molar volume were determined. For the studied glycyl dipeptides standard partial molar volume can be expressed by those of the corresponding amino acids in terms of an additivity scheme. The absorption spectra have also been recorded for present mixtures with the help of UV–vis spectrophotometer. The binding constant between amino acids/dipeptides and domiphen bromide was determined.

Thermodynamic properties of 1-butyl-3-methylimidazolium salicylate as an active pharmaceutical ingredient ionic liquid (API-IL) in aqueous solutions of glycine and L-alanine at T = (288.15–318.15) K

Thermodynamic properties of aqueous solutions of some amino acids, glycine and l-alanine with a novel ionic liquid containing salicylate anion, 1-butyl-3-methylimidazolium salicylate, [BMIM][SAL] as an active pharmaceutical ingredient ionic liquid (API-IL) have been investigated by volumetric, ultrasonic, refractometric and viscometric properties at T=(288.15–318.15K). The standard partial molar volume Vϕ0, partial molar volume of transfer ΔtraVφ0, Hepler’s constant (∂2Vϕ0/∂T2)p and apparent molar isentropic compressibility κφ have been calculated from density and speed of sound data. Viscosity and refractive index data were used for determination of viscosity B-coefficients (B), hydration number nH and molar refraction RD parameters. These parameters are helpful to study the structure promoting and solvation behaviour of the API-IL and various interactions present in the ternary solutions of (amino acid+[BMIM][SAL]+water).