Infinite Dilution Apparent Molar Volumes Research Articles

Studies on synthesis, physicochemical properties, biological activities of two novel berberine-based salts with DL-mandelate and cinnamate anions

Berberine (BBR) is a natural quaternary isoquinoline alkaloid which is derived from the traditional Chinese medicine Coptis chinensis and exerts various pharmacological effects. However, low solubility in water has greatly limited its clinical application. This study prepared two novel berberine-based salts (berberine DL-mandelate ([BBR][MAN]) and berberine cinnamate ([BBR][CIN])) to improve the physicochemical properties and bioavailability of berberine. Many techniques, like 1H and 13C NMR, FTIR, ESI-MS, and thermogravimetric analyzes were utilized to characterize two salts. The solubility and octanol/water partition coefficient in water and simulated body fluids (simulated body, simulated intestinal and simulated gastric fluids) were determined. Self-aggregation behaviors of two salts in water have been investigated by conductometry at different temperatures. The obtained critical aggregation concentration (cac) was used for the calculation of various thermodynamic properties namely standard Gibbs energy change (ΔGm0), enthalpy change (ΔHm0), and entropy change (ΔSm0) in the aggregation progress. The volumetric properties including the infinite dilution apparent molar volumes (V2,φ0), infinite dilution apparent molar expansibility (Eφ0) and thermal expansion coefficient (β) for [BBR][MAN] were also determined to study its solvation behavior in aqueous solution. In addition, the antibacterial effect of two salts on three strains (Staphylococcus aureus, Bacillus subtilis and Candida albicans) was measured, and the minimum inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) values were obtained. The results show that [BBR][MAN] has better antibacterial effect than [BBR][CIN]. The esterase-like activity assay demonstrated a decrease in enzyme activity of BSA in presence of two berberine-based salts. Cytotoxicity evaluation shows that two salts have potent in vitro anticancer activities against B16-F10 cancer cell lines.

Apparent molar volumes of ILs [EmimNTf2], [BmimNTf2], and [BmmimNTf2] in DEC and PEGMME solvents

Different groups have important influence on the interaction between molecules. In order to understand the effect of group introduction on the molecular interaction in solution, the densities of six diluted solutions including three ionic liquids (ILs) and two organic solvents were measured. The groups include methylene and methyl. The three ILs are 1-ethyl-3-methylimidazolium bis[(trifluoromethyl)sulfonyl]imide ([Emim][NTf2]), 1-butyl-3-methylimidazolium bis[(trifluoromethyl)sulfonyl]imide ([Bmim][NTf2]), and 1-butyl-2,3-dimethylimidazolium bis[(trifluoromethyl)sulfonyl]imide ([Bmmim][NTf2]). The organic solvents are diethyl carbonate (DEC) and propylene glycol monomethyl ether (PEGMME). The measured densities were used to calculate apparent molar volumes, Vϕ/cm3·mol-1, from 293.15 to 328.15 K with ± 0.02 K. Then, the fitting of infinite dilution apparent molar volumes, Vϕ0/cm3·mol-1, were obtained by using the calculated values of apparent molar volumes. The effects of different structures of ILs cations and organic solvents on the apparent molar volume, infinite dilution apparent molar volume, limiting apparent molar expansibility and thermal expansibility coefficient were discussed.

Densities and apparent molar volumes of diluent solutions of [EmimNTf2], [BmimNTf2], and [BmmimNTf2] in DEGDME and TEGDME

The densities of six diluents with molality of 0.0199to 0.5070 mol·kg−1 were measured at atmospheric pressure from 293.15 to 328.15 K. The studied ionic liquids (ILs) include 1-ethyl-3-methylimidazolium bis[(trifluoromethyl)sulfonyl]imide ([Emim][NTf2]), 1-butyl-3-methylimidazolium bis[(trifluoromethyl)sulfonyl]imide ([Bmim][NTf2]), and 1-butyl-2,3-dimethylimidazolium bis[(trifluoromethyl)sulfonyl]imide ([Bmmim][NTf2]). The solvents include diethylene glycol dimethyl ether (DEGDME) and tetraethylene glycol dimethyl ether (TEGDME). The measured densities were applied for calculation of VÐΦ/m3·mol-1 (apparent molar volume) from 293.15 K to 328.15 K. The influence of the introduction of methylene (–CH2-), methyl (–CH3) groups, and the structure of solvents on the density, apparent molar volume were discussed in depth. Redlich-Rosenfeld-Meyer (RRM) equation was used to fit VÐΦ/m3·mol-1 dependence on the molality of the six studied diluent solutions. Two parameter of VÐΦo/m3·mol-1 (infinite dilution apparent molar volume) and EÐΦ0/m3·mol-1·K-1 (limiting apparent molar expansibility) were also been fitted and discussed based on the RRM equation and polynomial equation, respectively. Besides, the interactions of ion-ion and ion–solvent were discussed according to the fitted parameters. The structure making or breaking were also discussed for IL in solvent.

Physicochemical study on molecular interactions of the active pharmaceutical ingredient ionic liquid domiphen salicylate with amino acids at different temperatures

The molecular interactions between the active pharmaceutical ingredient ionic liquid domiphen salicylate ([Dom][Sal]) and some amino acids (glycine, L-alanine, L-valine, L-leucine) in aqueous solution were studied. In order to accomplish this objective, the volume, conductivity and UV–vis spectroscopy of ternary systems were measured at different temperatures. The infinite dilution apparent molar volume, V2,φ0, transfer volume, ΔtV0, hydration number, nH and infinite dilution apparent molar expansibility, Eφ0 of amino acids in aqueous [Dom][Sal] solution were derived from the measured density data. Side chain contributions to V2,φ0 have been estimated. Critical micelle concentration, cmc, and thermodynamic properties of micellization (ΔGm0, ΔHm0,ΔSm0) for [Dom][Sal] in aqueous amino acids solutions were calculated using electrical conductivity data. The binding constant Kb of the amino acid with [Dom][Sal] was estimated based on the maximum absorbance data of the UV–vis spectroscopy. The impacts of temperature, concentration and the length of aliphatic chain of amino acids on these parameters were discussed. The mentioned parameters was employed to unveil the solute–solvent interactions in ternary systems.

Study of apparent molar volumes of ether functionalized ionic liquids with three ether solvents

The density of two functionalized ionic liquids (FILs) 1-methoxyethyl-3-methylimidazolium bis[(trifluoromethyl)sulfonyl]imide ([MOEmim][NTf2] and 1-methoxyethyl-2,3-dimethylimidazolium bis[(trifluoromethyl)sulfonyl]imide [MOEmmim][NTf2]) have been measured with ether solvents proprylene glycol monomethyl ether (PEGMME), diethylene glycol dimethyl ether (DEGDME), tetraethylene glycol dimethyl ether (TEGDME) at diluted concentration range. The determined temperature range is from 293.15 to 328.15 K at atmospheric pressure. The measured densities are used for the calculation of apparent molar volumes, Vϕ/m3·mol−1, at the temperature range. The effects of the ether (O) and methyl (CH3) introduction on imidazolium cation are discussed for the density and apparent molar volume in deeply. The Redlich-Rosenfeld-Meyer (RRM) equation was used for the fitting of apparent molar volumes, Vϕ/m3·mol−1, for the six studied dilute solutions. The infinite dilution apparent molar volumes, Vϕ/m3·mol−1, and limiting apparent molar expansibility, EΦ0/cm3·mol-1·K-1, have been obtained and discussed from the RRM equation and polynomial equation. The thermal expansion coefficients, α/K−1, have also been calculated and discussed from density for the studied dilute solutions in the temperature range.

Thermophysical, Acoustical, Spectral and DFT Study of Intermolecular Interactions of Terpinolene with Cresols

Densities and speed of sound were measured experimentally for binary mixtures of terpinolene with cresols (o-cresol, m-cresol, p-cresol) at three different temperatures 303.15, 308.15 and 313.15K at atmospheric pressure. From primary physical properties, some secondary properties like molar volume , excess molar volume , partial molar volume , excess partial molar volume , apparent molar volume , deviation in speed of sound , isentropic compressibility , deviation in isentropic compressibility , acoustical impedance , deviation in acoustical impedances , intermolecular free length , partial molar isentropic compression , excess partial molar isentropic compression and apparent molar isentropic compression were calculated. Infinite dilution apparent molar volume , infinite dilution apparent molar isentropic compression , empirical parameters , and , of the Redlich-Rosenberg-Mayer equation with the limiting apparent molar expansibility were also calculated. Some theoretical speed of sound calculating relations such as Nomoto relation , Ideal mixture relation , Junji relation and Free length theory relation were also calculated with their standard deviation . All the calculated values of excess/deviation properties were fitted with the fourth order Redlich-Kister polynomial equation and their standard deviation values were also calculated. FT-IR spectral analysis of binary mixtures at 4:1, 1:1 and 1:4 composition ratios were carried out at 298.15K. Computational calculations such as optimization of pure and binary mixtures in gas phase, bond length, Mulliken charges, theoretical vibrational frequencies and NBO calculations on basis of the DFT (Density Function Theory) were also carried out. The results were discussed in term of presence of intermolecular interactions, types, strength and behavior with change of temperatures and cresol components in binary mixtures.

Apparent molar volumes of hydrophobic imidazolium type ionic liquids with dimethyl carbonate

The density of four ionic liquids 1-alkyl-2-methylimidazolium bis[(trifluoromethyl)sulfonyl]imide ([C2mim][NTf2] and [C4mim][NTf2]), 1-alkyl-2, 3-dimethylimidazolium bis[(trifluoromethyl)sulfonyl]imide ([C2mmim][NTf2] and [C4mmim][NTf2]) have been determined with Dimethyl Carbonate (DMC) at lower concentration from 288.15 to 313.15 K at atmospheric pressure. Apparent molar volumes, Vϕ/m3·mol−1, have been calculated from the experimental densities. The effects of the methyl or methylene groups of the imidazolium cation on the above properties are discussed in deeply. The infinite dilution apparent molar volumes, Vϕ0/m3·mol−1 can be obtained from apparent molar volumes according to a Redlich-Rosenfeld-Meyer equation. The limiting apparent molar expansibility, Eϕ0/cm3·mol−1·K−1, have been calculated by the parameters from Redlich-Rosenfeld-Meyer equation. The thermal expansion coefficient, α/K−1, has also been calculated in the studied concentration range.

Volumetric, acoustic and viscometric investigation of ceftriaxone disodium in aqueous solutions of 1-propanol and 2-propanol

The extraction and purification of ceftriaxone disodium from aqueous solution carried out with organic solvents. Therefore volumetric, acoustic and viscometric properties of ceftriaxone disodium in aqueous solutions of 1–propanol and 2–propanol were investigated at T/K = (288.15–308.15). The apparent molar volumes and isentropic compressibility values in dilute region were fitted to Redlich-Mayer equation. The infinite dilution apparent molar transfer volumes, ΔtrVφo, were often negative and increased with increasing the concentration of 1–propanol and 2–propanol. This behaviour reveals that there are strong ionic-polar interactions between ions of CFNa and 1–propanol or 2–propanol with respect to water; because the polarizability of 1–propanol and 2–propanol is greater than those of water. The apparent molar isentropic compressibility at infinite dilution, κφo, of CFNa in the aqueous solutions of 1–propanol and 2–propanol are higher than those of pure water. Therefore the CFNa was dehydrated with addition of 1–propanol or 2–propanol. To obtain viscosity B and D coefficients, the viscosities data were fitted to the Jones-Dole equation. The viscosity B-coefficient of CFNa in the aqueous solutions of 1–propanol and 2–propanol was lower than those of CFNa pure water. Therefore it can be concluded that CFNa solvated in water rather than the aqueous solutions of 1–propanol and 2–propanol.

Volumetric and viscosity properties of glycine in ionic liquid + water solutions at 298.15 K

Densities and viscosities for the glycine + 1-alkyl-3-methylimidazolium bromide ([Cnmim]Br, n = 2, 4, 6) ionic liquids (ILs) + water systems were measured at 298.15 K. Meanwhile, the apparent molar volumes, VΦ, infinite dilution apparent molar volumes, VΦ0, standard volumes of transfer, ΔtVΦ0, of glycine and volumetric interaction parameters were further calculated. The viscosity B-coefficients of glycine in the aqueous IL solutions were calculated by using the Jones-Dole equation. The results show that both VΦ0 and ΔtVΦ0 values for glycine are positive and increase with increasing IL concentrations and follow the order: [C2mim]Br > [C4mim]Br > [C6mim]Br. However, the B-coefficients at given molalities of the ILs are in the order: [C2mim]Br < [C6mim]Br < [C4mim]Br. These phenomena are discussed and interpreted by means of the structural hydration interaction model and aggregation behavior of the [C6mim]Br in water. This work provides the important basic data for the understanding of the interaction between the ILs and amino acids/proteins and for the design of industrial processes.

Thermo-acoustical and volumetric studies on interionic interactions of l-histidine in aqueous maltose solutions at different temperatures

Apparent molar volumes, Vφ and adiabatic compressibilities, Ks, φ of l-histidine in the concentration range (0.0 to 0.18 mol kg−1) in maltose solutions ranging from pure water to 20.0 mass % of maltose have been calculated at 298.15, 303.15, 308.15 and 313.15 K from precise measurements of density and speed of sound. At infinite dilution apparent molar volumes, Vφ0, and apparent molar adiabatic compressibilities, Ks, φ0, of l-histidine have been also evaluated. Transfer volumes, ΔtrVφ0, and transfer adiabatic compressibilities, ΔtrKs, φ0, at infinite dilution from water to aqueous maltose solutions have been also calculated. Solute-solvent interaction has been confirmed with the positive value of Vφ in all the systems. Besides the reported values of Ks, φ were negative for l-histidine in aqueous-maltose solutions, indicating that the water molecules around ionic charged groups of amino acids are less compressible than the water molecules in the bulk solution. Interaction between saccharides and proteins molecules is expected to create polar environment, which helps to increase the hydrophobic interactions because of stabilizing the protein. The results indicate there exists strong solute–solvent (hydrophilic–ionic group and hydrophilic–hydrophilic group) interactions in these systems, which increase with increasing in saccharide concentration. It has also been observed that l-histidine acts as structure maker in aqueous-maltose solvents.

Investigation of Volumetric and Acoustic Properties of Ionic Liquid + Amino Acid + Water Systems at Different Temperatures

This paper reports density and speed of sound data for solutions of the ionic liquids (ILs) [C4mim]Cl and [C4mim][CF3SO3] in aqueous solution of 0.05 w/w amino acids of alanine, serine and proline at T = (288.15, 298.15, 308.15 and 318.15) K. From the experimental data measured, the apparent molar volume (Vϕ), isentropic compressibility ( ), and apparent molar isentropic compression ( ) have been calculated. The Vϕ values of [C4mim]Cl and [C4mim][CF3SO3] in the investigated aqueous amino acid solutions decreased by increasing the hydrophobicity of the amino acid and follow the order: serine ˃ alanine ˃ proline. The apparent molar volume and isentropic compressibility values at infinite dilution of the investigated ILs in the aqueous amino acid solutions and their variations with temperature have been determined. The infinite dilution apparent molar volume and adiabatic compressibility for transfer of the studied ILs from water to aqueous solutions of the amino acids have been calculated and the results were discussed in terms of different interactions existing in these solutions.

Intermolecular interactions behavior of terpinolene with some halobenzenes: A thermophysical, acoustical, spectral and DFT study

Densities, viscosities, speed of sound were experimentally measured for binary mixtures of terpinolene with some halobenzenes such as fluorobenzene, chlorobenzene, bromobenzene at 303.15, 308.15 and 313.15K at atmospheric pressure. Various secondary properties such as molar volume (Vm), excess molar volume (VmE), partial molar volume V−m,io, excess partial molar volume V−m,io,E, apparent molar volume (Vm,Φ,i), deviation in viscosity (Δη), excess Gibbs' free energy of activation of viscous flow (∆G∗E), deviation in speed of sound (Δu), isentropic compressibility (κs), deviation in isentropic compressibility (∆κs), acoustical impedance (z), deviation in acoustical impedances (Δz), intermolecular free length (Lf), partial molar isentropic compression K−s,m,io, excess partial molar isentropic compression K−s,m,io,E and apparent molar isentropic compression (Ks,m,Φ,i) were calculated from the values of primary physical properties. Infinite dilution apparent molar volume (Vm,Φ,1o), infinite dilution apparent molar isentropic compression (Ks,m,Φ,1o), empirical parameters Sv, Bv and Sk, Bk of the Redlich-Rosenberg-Mayer equation with the limiting apparent molar expansibility (EΦo) were also calculated. Some theoretical viscosity of binary mixtures calculating relations like Bingham, Arrhenius, Kendall-Munroe, Grunberg-Nissan (G12), Dolezalek-Schulze (D12), Tamura-Kurata (T12), Katti-Chaudhari (Wvis/RT), and 3-body McAllister (M12, M21) and some theoretical speed of sound calculating relations such as Nomoto relation (unmt), Ideal mixture relation (uimr), Junji relation (ujunji) and Free length theory relation (uflt) were also calculated. FT-IR analysis of binary mixtures at 4:1, 1:1 and 1:4 composition ratios were carried out. The DFT (Density Function Theory) based computational calculations such as bond length, Mulliken charges, theoretical vibrational frequencies, solvation model and NBO calculations were also studied. All the results of excess/deviation properties were fitted with the Redlich-Kister polynomial equation. The results were discussed in term of types, strength and behavior of intermolecular interaction present between components of binary mixtures.

Effect of 1–butyl–4–methylpyridinium and 1–butyl–3–methylimidazolium halide ionic liquids on the interactions of lactic acid in the aqueous solutions of polyethylene glycol

In this study, effect of some ionic liquids on the thermodynamic and transport properties of L(+)–lactic acid in aqueous polyethylene glycol solutions have been investigated. Density, speed of sound, and viscosity of L(+)–lactic acid in the aqueous solutions of polyethylene glycol, polyethylene glycol +1–butyl–3–methylimidazolium bromide, polyethylene glycol +1–butyl–3–methylimidazolium chloride, polyethylene glycol +1–butyl–4–methylpyridinium bromide, and polyethylene glycol +1–butyl–4–methylpyridinium chloride were measured at T/K=(288.15, 298.15, 308.15 and 318.15). Infinite dilution apparent molar volumes, transfer apparent molar volume, infinite dilution apparent molar isentropic compressibility and viscosity B–coefficient of L(+)–lactic acid were calculated using experimental data and were discussed in terms of solute–solute and solute–solvent interactions. The results reveal that solute–solvent interactions were decreased with increasing temperature, size of halide anion. Also solute–solvent interactions in the presence pyridinium ionic liquids are stronger than those of imidazolium ionic liquids. The obtained results from spectroscopic reveal that λmax of imidazolium based ionic liquids were red shifted in the presence of lactic acid and this behaviour confirmed existence hydrogen bound between lactic acid and imidazolium based ionic liquids.

COMPORTAMIENTO VOLUMÉTRICO DE LA DL-VALINA EN SOLUCIONES ACUOSAS DE NITRATO DE SODIO A DIFERENTES TEMPERATURAS

Densities of DL-valine (2-amino-3-methylbutanoic acid) in aqueous solutions of sodium nitrate were determined at temperatures ranging from 283.15 to 318.15 K using an Anton Paar DMA 5000 vibrating tube densitometer. The apparent molar volume, infinite dilution apparent molar volume, second derivative of the infinite dilution partial molar volume with respect to temperature, partial molar volume of transfer at infinite dilution and the number of hydration were calculated. The results obtained were discussed in terms of the dominant interactions in solution, it was found that the DL-valine has a disruptor effect in the structure of the solvent and that at infinite dilution solute-solvent interactions are dominant between isopropyl group the amino acid and sodium and nitrate ions.

Densities and viscosities of binary mixtures N , N -dimethyl-N-(3-sulfopropyl)cyclohexylammonium tosylate with water and methanol at T = (303.15 to 328.15) K

Abstract Densities, ρ and viscosities, η of N , N -dimethyl-N-(3-sulfopropyl)cyclohexylammo-nium tosylate ([CyN 1,1 PrSO 3 H][Tos]) with water and methanol were measured, at temperatures from 303.15 K to 328.15 K with 5 K interval and 0.1013 MPa, as a function of [CyN 1,1 PrSO 3 H][Tos] molality (or mass fraction). The isobaric thermal expansion coefficient, molecular volume, standard molar entropy, and lattice energy of the pure IL were obtained based on the density data of pure IL. The apparent molar volume, V φ , infinite dilution apparent molar expansibility, E φ ∞ and energy barrier, E were calculated from the experimental data. The Redlich-Mayer equation was used to evaluate infinite dilution apparent molar volume, V φ ∞ . In addition, viscosities can be described satisfactorily by Vogel-Fulcher-Tammann (VFT) equation. The V φ ∞ values of the IL in water are higher than those in methanol, which suggests that the ion-solvent interactions for [CyN 1,1 PrSO 3 H][Tos] + water binary system are stronger than those for [CyN 1,1 PrSO 3 H][Tos] + methanol. And the energy barrier values decrease with the drop of IL mass fraction in both systems, indicating that the viscosity changes of binary mixtures are more sensitive to the temperature at high composition of the IL.

Molar volumes and viscosities of N-[(4-bromo-3,5-difluorine)phenyl] maleimide (BDPM)-DMF-toluene and BDPM-DMF-ethanol mixtures in a range 298 to 318 K

N-[(4-bromo-3,5-difluorine)phenyl]maleimide(BDPM) is a new monomer for polyreaction. Its densities and viscosities of BDPM+DMF(vol=30%)+Toluene(vol=70%) and BDPM+DMF(vol=30%)+Ethanol(vol=70%) have been determined experimentally under normal atmospheric pressure over the entire molality range from (293.15 to 318.15) K. The apparent molar volumes and infinite dilution apparent molar volumes of BDPM+DMF(vol=30%)+Toluene(vol=70%) and BDPM+DMF(vol=30%)+Ethanol(vol=70%) were calculated from experimental measurements. Results were fit to obtain the appropriate parameters and standard deviations between the measured and fitted values.

Volumetric and compressibility behaviour of poly(propylene glycol) – Amino acid aqueous solutions at different temperatures

Precise density and sound velocity measurements have been carried out for aqueous solutions of PPG725 in the absence and presence of (0.2 and 0.5)mol·kg−1 amino acids: alanine, glycine, serine and proline, and also for aqueous solutions of these amino acids in the absence and presence of 0.01w/w PPG725 at T=(288.15, 293.15, 298.15, 303.15 and 308.15)K. From the experimental density and sound velocity values, the apparent molar volume and isentropic compressibility have been obtained and extrapolated to infinite dilution. The infinite dilution apparent molar properties for transfer of PPG from water to aqueous amino acids solutions and also those for transfer of amino acids from water to aqueous PPG solutions have been studied. Temperature dependency of the infinite dilution apparent molar volume was utilised to determine structure-breaker or structure-maker effects of the solutes. Hydration numbers of the amino acids in the investigated aqueous solutions have been evaluated from the volumetric and compressibility properties. All results are discussed based on the salting-out aptitude of the amino acids (hydrophilic+hydrophobic) interactions and (hydrophobic+hydrophobic) interactions occurred between PPG and the investigated amino acids.

Volumetric and Acoustic Properties of a DBU (1,8-Diazobicyclo[5.4.0]undec-7-ene) Based Protic Ionic Liquid in Water at T = (293.15 to 328.15) K

The protic ionic liquid, 1,8-diazabicyclo[5.4.0]undec-7-en-8-ium trifluroacetate [DBUTFA], has been synthesized and densities of and speeds of sound in (DBUTFA + water) binary mixtures were measured simultaneously using a vibrating-tube digital density and speed of sound analyzer (Anton Paar, DSA 5000 M) at T = (293.15 to 328.15) K, with 5 K interval, and at atmospheric pressure. From the experimental density and speed of sound data, apparent molar volumes, \( V_{\phi } \), and apparent molar isentropic compressibilities, \( K_{S,\phi } \), were determined and further analyzed using Redlich–Mayer type equations to evaluate the corresponding infinite dilution apparent molar volumes, \( V_{2}^{\infty } \), infinite dilution apparent molar isentropic compressibilities, \( K_{S,2}^{\infty } \), and empirical parameters (SV, BV, Sk and Bk). The positive magnitude of the limiting volumetric slopes, SV versus m1/2 for this protic ionic liquid (PIL) in aqueous solutions, suggests that PIL–water interactions are weak.

Apparent molar properties of aqueous protic ionic liquid solutions at T = (293.15 to 328.15) K

Apparent molar volumes and apparent molar isentropic compressibilities of newly synthesized ammonium-based protic ionic liquid (PIL), namely diethylethanolammonium propionate, at T = (293.15 to 328.15) K and at atmospheric pressure were obtained from experimentally measured density and speed of sound data. Redlich-Mayer type of equation was used to calculate infinite dilution apparent molar volumes, V 2 ∞ , infinite dilution apparent molar isentropic compressibilities, K s,2 ∞ , and corresponding empirical parameters (S v, B v, S k, and B k). Positive magnitude of limiting volumetric slope S v versus m 1/2 for protic ionic liquid (PIL) + water binary solutions, suggests that PIL-water interactions are weak. Further, the temperature dependence of V 2 ∞ values has also been evaluated.

Interactions of glycine in aqueous solutions of 1-butyl-3-methylimidazolium tetrafluoroborate at different temperatures

INTERACTIONS OF GLYCINE IN AQUEOUS SOLUTIONS OF 1-BUTYL-3-METHYLIMIDAZOLIUM TETRAFLUOROBORATE AT DIFFERENT TEMPERATURES. Densities of glycine in aqueous solutions of ionic liquid 1-butyl-3-methylimidazolium tetrafluoroborate were determined at temperatures ranging from 283.15 to 313.15 K. The apparent molar volume, infinite dilution apparent molar volume, second derivative of the infinite dilution partial molar volume with respect to temperature, partial molar volume of transfer at infinite dilution, and the number of hydration were determined. It was found that the apparent molar volume at infinite dilution was positive, but decreased with increasing ionic liquid concentration and increased with increasing temperature. On the other hand, the partial molar volume of transfer at infinite dilution behaved in a similar manner, but was negative. Keywords: volumetric properties; interactions in solution; glycine in aqueous ionic liquid.