Apparent Molar Isentropic Compressibility Research Articles

Solvation of alkaline earth metal ions in N,N-dimethylformamide and N,N-dimethylacetamide – A volumetric and acoustic study

Densities and sound velocities at temperatures (298.15, 303.15, 308.15, 313.15 and 318.15)K of magnesium(II), calcium(II) and strontium(II) trifluoromethanesulfonates (triflates), as well as barium(II) perchlorate in N,N-dimethylformamide (dmf) and N,N-dimethylacetamide (dma) have been measured over the composition range studied. From these results, apparent molar volumes and apparent molar isentropic compressibilities at infinite dilution, as well as expansibilities have been evaluated. The results have been discussed in terms of ion–solvent interactions and coordination number.

Investigation on solute–solvent interactions of glycine, l-alanine and l-valine in aqueous tetraethylammonium iodide solutions at different temperatures with reference to volumetric and acoustic measurements

The interactions of amino acids glycine, l-alanine and l-valine with tetraethylammonium iodide (TEAI) as a function of temperature have been investigated by a combination of volumetric and acoustic measurement. Densities (ρ) and ultrasonic speeds (u) of amino acids in aqueous solutions of TEAI have been measured at T=(288.15, 293.15, 298.15, 303.15 and 308.15)K and p=0.1MPa. The apparent molar volume (V∅), the partial molar volume (V∅0) and standard partial molar volumes of transfer (ΔV∅0) for amino acids from water to aqueous TEAI solutions have been calculated from density values. Apparent molar isentropic compressibility (K∅,s), partial molar isentropic compressibility (K∅,s0), partial molar isentropic compressibility of transfer (ΔK∅,s0) have been calculated from values of the ultrasonic speed. The pair and triplet interaction coefficients have been calculated from both properties. The linear variation of V∅0 with the number of carbon atoms in the alkyl chain of amino acids has been utilized to calculate the contribution of the charged end groups (NH3+,COO-), (CH2) group and other alkyl chains of the amino acids to V∅0. The results obtained are discussed in the light of various interactions operating in ternary systems of amino acids, water and TEAI.

Densities, Sound Speed, and Viscosities of Some Amino Acids with Aqueous Tetra-Butyl Ammonium Iodide Solutions at Different Temperatures

Apparent molar volumes (V⌀), apparent molar isentropic compression (K⌀,s), and viscosity B coefficient of glycine, l-alanine, and l-valine in (0.01 and 0.03) mol·kg–1 aqueous tetrabutyl ammonium iodide (TBAI) solutions have been determined at temperatures (288.15, 293.15, 298.15, 303.15, and 308.15) K from their experimental density, ultrasonic speed, and flow time measurements, respectively. Partial molar volumes (V⌀0) and partial molar isentropic compression (K⌀,s0) have been determined from the above measurements. Further, these data were used to calculate the corresponding transfer parameters (ΔV⌀,s0 and ΔK⌀,s0), hydration number (nH), side chain group contributions of V⌀0, and viscosity B coefficients of the amino acids, partial molar expansibilities (E⌀0), (dB/dT), and related parameters. The trends of variations of experimental and computed parameters have been discussed in terms of solute–solvent interactions with an emphasis on structure-making and structure-breaking ability of the above amino ac...

Solute solvent interactions of mono saccharides D(−)-ribose and D(+)-xylose in aqueous trisodium citrate solutions at different temperatures

Densities and speed of sound measurements of two mono-saccharides D(−)-ribose and D(+)-xylose have been taken in water and in aqueous trisodium citrate in concentration (0.2, 0.4, and 0.6) mol kg−1 at T=(288.15, 298.15, 308.15 and 318.15) K and atmospheric pressure. Apparent molar volumes (Vϕ), apparent molar volumes at infinite dilution (Vϕ0) and corresponding transfer apparent molar volumes (ΔVϕ0), partial molar expansion coefficients (∂Vϕ0/∂T)P and their second derivative (∂2Vϕ0/∂T2)P, isentropic compression (Kϕ,S), isentropic compression at infinite dilution (Kϕ,S0), transfer apparent molar isentropic compression at infinite dilution (ΔKϕ,S0) have been calculated using experimental density and speed of sound data. The results have been discussed in terms of different types of interactions occurring in the present system.

Influence of iso-perthiocyanic acid and temperature on the aggregation properties of sodium dodecylsulphate in dimethylsulphoxide

This paper investigates the effect of a heterocyclic compound, iso-perthiocyanic acid (IPA) (0.01, 0.05, and 0.10mol∙kg−1) on the micellization behavior of sodium dodecylsulphate (SDS) (1–52mmol∙kg−1) in dimethylsulphoxide (DMSO) by employing three conventional techniques viz. conductivity, density, and speed of sound measurements over a wide temperature range (293.15–313.15K). From all the techniques, the critical micelle concentration (CMC) values have been determined, and the results have been discussed in terms of SDS-IPA solvophobic and hydrogen bonding interactions in DMSO. The temperature dependence of the CMC values has proved the dominance of disruption of structured DMSO molecules around the alkyl chain of SDS. Further, the XCMC values have been used to calculate the standard thermodynamic parameters of micellization like enthalpy (ΔHmo), free energy (ΔGmo), and entropy (ΔSmo). The density and speed of sound data have been used to evaluate the volumetric and compressibility parameters like apparent molar volume (ϕv), isentropic compressibility (Ks), and apparent molar isentropic compression (ϕκ) to get more clear insight with regards to solute–solute / solute–solvent interactions existing in the present SDS–IPA–DMSO ternary system. In addition, an attempt has also been made to examine the antifungal activity of IPA in combination with SDS in aqueous medium.

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.

Thermodynamic study of aspirin in the presence of ionic liquid, 1-hexyl-3-methylimidazolium bromide in acetonitrile at T = (288.15 to 318.15) K

In recent years, ionic liquids have received much attention in pharmaceutical processing. Thermophysical properties such as densities, viscosities, speeds of sound and refractive indices for systems containing aspirin (ASA), ionic liquid {1-hexyl-3-methylimidazolium bromide ([HMIm]Br)} and acetonitrile have been measured at T=(288.15K to 318.15) K and at atmospheric pressure. The measured data have been applied to calculate the standard partial molar volumes Vϕ0, volumes of transfer ΔtrVϕ0, Hepler's constants ∂2Vϕ0/∂2TP, apparent molar isentropic compressibility κφ, molar refractions RD, viscosity B-coefficients and solvation numbers. The calculated Hepler's constants ∂2Vϕ0/∂2TP indicate that the ionic liquid behave as structure-maker in the solutions. The results have been interpreted in terms of solute–solvent interactions. Generally it is concluded that dominant interactions between ASA and ionic liquid are ion–polar and polar–polar interactions.

Thermodynamic and ultrasonic properties of ascorbic Acid in aqueous protic ionic liquid solutions.

In this work, we report the thermodynamic and ultrasonic properties of ascorbic acid (vitamin C) in water and in presence of newly synthesized ammonium based protic ionic liquid (diethylethanolammonium propionate) as a function of concentration and temperature. Apparent molar volume and apparent molar isentropic compression, which characterize the solvation state of ascorbic acid (AA) in presence of protic ionic liquid (PIL) has been determined from precise density and speed of sound measurements at temperatures (293.15 to 328.15) K with 5 K interval. The strength of molecular interactions prevailing in ternary solutions has been discussed on the basis of infinite dilution partial molar volume and partial molar isentropic compression, corresponding volume of transfer and interaction coefficients. Result has been discussed in terms of solute-solute and solute-solvent interactions occurring between ascorbic acid and PIL in ternary solutions (AA + water + PIL).

Density, Viscosity, Speed of Sound, and Refractive Index of a Ternary Solution of Aspirin, 1-Butyl-3-methylimidazolium Bromide, and Acetonitrile at Different Temperatures T = (288.15 to 318.15) K

Solvation properties of aspirin in nonaqueous ionic liquid solutions are of importance in pharmaceutical point of view. The effect of an ionic liquid on the thermodynamic properties of this drug in acetonitrile solutions has been investigated. The thermophysical properties including densities, viscosities, speeds of sound, and refractive indices for systems containing aspirin (ASA), ionic liquid {1-butyl-3-methylimidazolium bromide ([BMIm]Br)}, and acetonitrile (MeCN) have been measured at T = (288.15 to 318.15) K and atmospheric pressure. The measured data have been used to calculate the standard partial molar volumes Vϕ0, apparent molar isentropic compressibility κϕ0, molar refractions RD, and viscosity B coefficients. The calculated Hepler’s constants (∂2Vϕ0/∂2T)P indicate that the ionic liquid behaves as a structure-maker in the studied solutions. The transfer volumes ΔtVϕ0 show that dominant interactions between aspirin and ionic liquid are ion–polar and polar–polar interactions. The results have bee...

Volumetric and ultrasonic properties of ternary (sucrose + water + protic ionic liquid) solutions

In this work, apparent molar volume and apparent molar isentropic compressibility of sucrose in aqueous solutions of ammonium based protic ionic liquid (PIL) have been evaluated from experimentally determined values of density and speed of sound at T=(293.15, 298.15, 303.15, 308.15, 313.15 and 318.15)K and at 101.3kPa. The types of interactions occurring between sucrose and PIL (3-hydroxypropylammonium formate; 3HPAF) in aqueous solutions were studied and are discussed on the basis of infinite dilution partial molar volumes, V2°, and isentropic compressibility, Ks,2°, transfer volume and compressibility (ΔtV2° and ΔtKs,2°), expansion coefficients, [(∂V2°/∂T)P and (∂2V2°/∂T2)P], interaction coefficients, (YAB and YABB) and hydration numbers, Nw. Further, apparent specific volume, ASV and apparent specific isentropic compression, ASIC were determined and analysed to evaluate the effect of PIL on the basic taste quality of sucrose.

Volumetric Properties of Disaccharides in Aqueous Solutions of Benzyldimethylammonium Acetate as a Function of Temperature

Densities, ρ, and speeds of sound, u, of two disaccharides (D-(+)-maltose and D-(+)-cellobiose) in water and in the presence of protic ionic liquid (PIL) (i.e., benzyldimethylammonium acetate, BDMAAc) were measured at different temperatures (288.15–318.15) K at atmospheric pressure. These data were used to calculate the apparent molar volume, apparent molar isentropic compressibility, infinite dilution partial molar volume, infinite dilution partial molar isentropic compressibility, and corresponding transfer parameters (ΔtV°2 and ΔtK°s,2) for disaccharides from water to aqueous PIL solutions. The effect of BDMAAc on the basic taste quality of disaccharides was evaluated from apparent specific volume and apparent specific isentropic compressibility, as these parameters are grouped in various taste qualities.

Effect of protic ionic liquid on the volumetric properties of ribose in aqueous solutions

The densities, ρ and speeds of sound, u of d(−)-ribose in aqueous solutions of ammonium based protic ionic liquid i.e., 3-hydroxypropylammonium acetate (3HPAAc) have been measured at temperatures (298.15–318.15)K and at atmospheric pressure. These experimental data were used to calculate apparent molar volumes, V2,φ, apparent molar isentropic compressibilities, Ks,2,φ, infinite dilution partial molar volumes, V2°, and partial molar isentropic compressibilities, K°s,2 and the corresponding volumes of transfer (ΔtV2° and ΔtK°s,2). Both ΔtV2° and ΔtK°s,2 values were found to be positive, which increase with cosolute (3HPAAc) concentration and temperature, which indicate the presence of hydrophilic-ionic types of interactions between d(−)-ribose (Rib) and ions of 3HPAAc. Various derived parameters such as expansion coefficients, hydration numbers, pair and triplet interaction coefficients for Rib in aqueous 3HPAAc solutions have also been evaluated and discussed.

Acoustic and Volumetric Properties of Diluted Solutions of Water in Ionic Liquids

Herein, we report the densities and speeds of sound in binary mixtures of three hydrophobic and one hydrophilic ionic liquids: 1-butyl-3-methylimidazolium bis[(trifluoromethyl)sulfonyl]imide, [C4mim][NTf2], 1-butyl-1-methylpyrrolidinium bis[(trifluoromethyl)sulfonyl]imide, [C4mpyr][NTf2], 1-propyl-3-methylimidazolium bis[(trifluoromethyl)sulfonyl]imide, [C3mim][NTf2] and 1-ethyl-3-methylimidazolium thiocyanate, [C2mim][SCN], with water at 298.15 K and 0.1 MPa. The concentration range of water, which encompassed relatively small values well below the saturation point, is often regarded as an impurity for hydrophobic ionic liquids. On the basis of experimental results the molar volume, adiabatic molar compressibility, partial molar volume and apparent molar volume, as well as, partial molar and apparent molar isentropic compressibility properties were then calculated. Interesting results are obtained using the solutions based on the hydrophilic [C2mim][SCN], since these mixtures are characterized by relatively low density and high values of speed of sound. Furthermore, the partial molar volumes and partial molar adiabatic compressibilities of water in solution with [C2mim][SCN] are the lowest among the investigated in mixtures with ionic liquids. However, in the case of the hydrophobic ionic liquid solutions, only small differences are observed for molar adiabatic compressibilities with the change of the cation structure, i.e. for water + [C4mim][NTf2] or + [C4mpyr][NTf2]. A more pronounced difference has been observed for the partial molar compressibility of water in solutions with these two ionic liquids.

Effect of sodium chloride and myo-inositol on diphenhydramine hydrochloride drug in aqueous solution at different temperatures: Volumetric and acoustic approach

Densities and speeds of sound of diphenhydramine hydrochloride (DPH) in aqueous solution and 0.06mol·kg−1 aqueous solutions of sodium chloride and myo-inositol (MI) have been measured at different temperatures, T=(288.15, 298.15 and 308.15)K over the concentration range (0.01 to 0.1)mol·kg−1. Density and speed of sound values were used to evaluate thermodynamic properties such as apparent molar volume (Vϕ), isentropic compressibility (κs) of solution, apparent molar isentropic compressibility (κϕ) of solute, of diphenhydramine hydrochloride in water and in aqueous solutions of sodium chloride and myo-inositol. The limiting apparent molar expansivity (Eϕ0) of solute and coefficient of thermal expansion (α∗) of DPH in aqueous binary and ternary solutions have also been computed. Limiting values of apparent molar volume (Vϕ0) and apparent molar compressibility (κϕ0) were obtained from the plots Vϕ and κϕ as a function of molality and have been utilized in obtaining transfer volumes (ΔtrVϕ0) and transfer compressibilities (Δtrκϕ0) of diphenhydramine hydrochloride from water to aqueous solutions of sodium chloride and myo-inositol at different temperatures. The transfer volume and transfer compressibility at infinite dilution calculated from (Vϕ0) and (κϕ0) were found to have positive values. The results obtained have been interpreted in terms of various interactions taking place among solute and solvent molecules.

Partial molar volume and isentropic compressibility of symmetrical and asymmetrical quaternary ammonium bromides in aqueous solution

Values of apparent molar volume and isentropic compressibility of symmetric and asymmetric isomers of tetrabutylammonium bromide, namely tetra-n-butylammonium bromide, tetra-iso-butylammonium bromide, tetra-sec-butylammonium bromide, di-n-butyl-di-iso-butylammonium bromide and di-n-butyl-di-sec-butylammonium bromide, in aqueous solution were determined from density and speed of sound measurements. These properties were obtained as a function of molal concentration within the range of 0.01<m/mol·kg−1<0.1 covering temperatures from 278.15⩽T/K⩽293.15. The partial molar volumes and the apparent isentropic molar compressibility at infinite dilution were calculated and their dependence on temperature examined. The results show that cations with sec-butyl chains have larger structural volumes compared to those with iso-butyl chains. In addition, cations with sec-butyl chains induce smaller structural changes in their hydration shell than the others.

Study of solute–solute and solute–solvent interactions of N-acetyl glycine in aqueous d-fructose solutions at different temperatures

Densities (ρ) and ultrasonic speeds (u) for N-acetyl glycine (AG) in (0.05, 0.15, 0.25 and 0.35molkg−1) aqueous d-fructose (FR) solutions have been measured at temperatures (288.15, 293.15, 298.15, 303.15 and 308.15)K and at pressure 101kPa. These data have been used to calculate apparent molar volume (Vϕ) and acoustical parameters, coefficient of isentropic compression (βs), molal hydration number (nH) and apparent molar isentropic compression (Kϕ,s). Partial molar volumes (Vϕ0) and partial molar isentropic compression (Kϕ,s0) of AG at infinite dilutions were also evaluated. The partial molar volumes of transfer (ΔVϕ0) and partial molar isentropic compression of transfer (ΔKϕ,s0) of AG from aqueous to aqueous FR solutions have been calculated and interpreted in terms of solute-co-solute interactions. Pair and triplet interaction coefficients have also been calculated. The results have been used to investigate the solute–solute and solute–solvent interactions as well as the effect of the concentration of FR on these interactions. It is observed that there exist strong solute–solvent interactions in these systems. The data of transfer parameters suggest that the type of interactions present in these systems are complex depending both on the nature of side group as well as on temperature.

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.

Volumetric, compressibility and viscometric studies on sodium cholate/sodium deoxycholate–amino acid interactions in aqueous medium

This paper reports density, speed of sound, and viscosity data for the bile salts: sodium cholate (1–30mmolkg−1) and sodium deoxycholate (1–17mmolkg−1) in 0.1molkg−1 aqueous solution of amino acids viz. glycine, leucine, methionine, and histidine at different temperatures (293.15–318.15K) under atmospheric pressure. From the experimental density and speed of sound data, the apparent molar volume (ϕv), isentropic compressibility (κs), and apparent molar isentropic compression (ϕκ) have been calculated, and the results have been interpreted in terms of different hydrophobic and electrostatic interactions pertaining in the bile salt–amino acid–water ternary system. Based on experimental viscosity data, the relative viscosity (ηr) and viscous relaxation time (τ) have been calculated and their dependence on concentration of bile salts and temperature has confirmed the existence of significant amount of bile salt–amino acid interactions.

Effect of DBU (1,8-Diazobicyclo[5.4.0]undec-7-ene) Based Protic Ionic Liquid on the Volumetric and Ultrasonic Properties of Ascorbic Acid in Aqueous Solution

In order to understand the strength and type of interactions involved in ternary solutions, the effect of solute or cosolute concentration and temperature is needed, as an understanding of these interactions is helpful in biochemical and biophysical chemistry. In this regard, we have studied the volumetric and ultrasonic properties of one of the most important vitamins, i.e., ascorbic acid, in water and in the presence of newly synthesized protic ionic liquid (1,8-diazabicyclo[5.4.0]undec-7-en-8-ium trifluoroacetate) at temperatures of 293.15–328.15 K and at atmospheric pressure. The experimentally measured density and speed of sound data were used to calculate apparent molar volume and isentropic compressibility, infinite dilution partial molar volume, and partial molar isentropic compressibility. Volume of transfer (ΔtV2° and ΔtK°s,2), expansion coefficients, pair and triplet volumetric interaction coefficients were also evaluated and discussed in terms of various interactions occurring between ascorbic...

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.