Apparent Molar Volume Of Solute Research Articles

Physiochemical study of 1-methyl imidazole trifluoro methane sulfonate ionic liquid in aqueous and aqueous amino acid solutions at different temperatures

The experimental density and speed of sound of 1-methyl imidazole trifluoro methane sulfonate ionic liquid in aqueous binary ([MIm][OTf]+H2O) solution and aqueous ternary ([MIm][OTf] + 0.05 mol.kg−1 aqueous glycine) solution are reported in the dilute concentration range (0.06 to 0.16 mol.kg−1) at the temperature between 288.15 and 318.15 K with 5K interval and at atmospheric pressure. These density (ρ) and speed of sound (u) data are utilized to derive various significant thermophysical parameters namely apparent molar volume of solute (Vϕ), isentropic compressibility of solution (κs) and apparent molar isentropic compressibility of solute (KS,ϕ). The limiting apparent molar volume (Vϕ0) and limiting apparent molar isentropic compressibility (KS,ϕ0) of [MIm][OTf] are estimated by extrapolation methods. By using Vϕ0and KS,ϕ0data of the studied binary and ternary systems, the values of transfer volumes i.e. volume changes due to transfer (ΔtrVϕ0)and transfer compressibility i.e. compressibility changes due to transfer(ΔtrKsϕ0) from aqueous to aqueous amino acid solution are estimated. The observed ΔtrVϕ0and ΔtrKsϕ0values are temperature dependent. The outcomes of this investigation are framed within the context of solute-solute and solute-solvent interactions.

Expliciting the interactions of tramadol hydrochloride + choline chloride-based deep eutectic solvent + water systems: Thermodynamic aspects

In recent years, a new class of environmentally friendly solvents called deep eutectic solvents (DESs) have been employed in a number of operations in both academia and industry. The study described herein offers an assessment of a green solvent in the preparation of Drug delivery systems (DDSs) as well as delivery vehicles made of a deep eutectic system (DES) constituted of Choline Chloride (ChCl) and Urea (U). For the designing of such processes, there is a need for an understanding of the molecular interaction of Tramadol hydrochloride with DES. In this regard, we have experimentally measured density and sound velocity for Tramadol hydrochloride in aqueous solutions and in different concentrations of aqueous DES (i.e., 0.25, 0.50, and 1.0)mol.kg−1 within the concentration range 0 to 0.15 mol.kg−1 at various temperatures (288.15, 298.15, 308.15 and 318.15) K. In order to interpret the view on solute–solvent and solute–solute interactions, several derived parameters chiefly apparent molar volume of solute (Vϕ), isentropic compressibility (κS), apparent molar isentropic compressibility of solute (KS,ϕ) for tramadol hydrochloride in aqueous and in an aqueous DES solutions have been calculated from experimental density and speed of sound values. The limiting apparent molar volume of solute (Vϕ0) and limiting apparent molar isentropic compressibility of solute (KS,ϕ0) for binary as well as ternary systems have been calculated from apparent molar volume and compressibility values. The thermal coefficient of expansion (α) and partial molar isobaric expansion (Eϕ0) have been derived from the temperature dependence of limiting apparent molar volume of solute. Transfer volume (ΔVϕtrans0) and transfer compressibility ΔKS,ϕtrans0 of tramadol hydrochloride from aqueous to aqueous DES solutions have been calculated.

Thermophysical properties of 1-butyl-3-methylimidazolium octyl sulfate ionic liquid in aqueous and aqueous electrolyte solutions at different temperatures

Understanding the molecular interaction of 1-butyl-3-methylimidazolium octyl sulfate i.e., [Bmim][OcOSO3] in water and in aqueous NaCl solution is important for fabricating the new process. As it is already known that ionic liquids along with inorganic salt NaCl have significant potential in the tribology of lubricants and salting-out media for the separation of nicotine. It is known that ionic liquids exhibit characteristic behavior at solid−liquid interfaces. Although it is believed that the structure of ionic liquids at the interface contributes to the tribological properties in the region of boundary-mixed lubrication, this contribution has not been clarified yet. Thus, we study the molecular interaction of the ionic liquid in aqueous and ionic liquid in aqueous NaCl solutions through the thermodynamic approach. We have measured density as an important parameter for 1-butyl-3-methylimidazolium octyl sulfate i.e., [Bmim][OcOSO3] in water and in aqueous NaCl solution within the concentration range of 0.04-0.12 mol/kg at different temperatures i.e. 293.15, 298.15, 303.15, 308.15, and 313.15 K and atmospheric pressure by using a densitometer (DSA5000M Anton Paar). The density (ρ) data were employed to measure some derived parameters such as apparent molar volume of solute (Vϕ), limiting apparent molar volume of solute (Vϕ0), thermal expansion coefficient (α), apparent molar expansivity of solute at finite concentration (Eϕ) and at infinite concentration (Eϕ0) and transfer volume (ΔtrVϕ0). Results have been discussed in terms of all the possible molecular interactions in systems.

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.

An insight into the thermodynamic investigation of important metabolite(KCl)-methyl nicotinate in aqueous solution at various temperatures

We report in this communication, the data on density and speed of sound measurements for methyl nicotinate in aqueous and in 0.1 mol.kg−1 aqueous potassium chloride solutions and potassium chloride (KCl) in water and in mixture containing fixed concentration (0.1 mol.kg−1) of Methyl nicotinate (MN) solution and varying the concentration (0.01 mol.kg−1 to 0.16 mol.kg−1) at 288.15, 293.15, 298.15, 303.15, 308.15, 313.15 and 318.15 K and atmospheric pressure. The density data are used to measure apparent molar volume of solute at finite concentrations(Vϕ) and apparent molar volume of solute at infinitely dilute solutions (Vϕ0) in binary and ternary mixtures. The speed of sound data are used to measure isentropic compressibility (κS), apparent molar isentropic compressibility of solute at finite concentrations (KS,ϕ) and apparent molar compressibility of solute at infinitely dilute solutions (KS,ϕ0) for binary and ternary mixtures . The coefficient of thermal expansion (α), apparent molar expansivity of solute (Eϕ) and limiting apparent molar expansivity (Eϕ0) of solute for binary and ternary solutions at 293.15, 298.15, 303.15, 308.15 and 313.15 K have also been measured. These parameters are being used to assist in the exploration of feasible intermolecular interactions in studied binary and ternary mixtures. The structure making/breaking ability of solute in binary and ternary solutions were also examined using Hepler's constant. All these results are analyzed and discussed on the basis of solute–solute and solute–solvent interactions.

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.

Insights into the temperature and concentration dependent studies of the Anti-diabetic drug in aqueous binary and ternary (water +sucrose) mixtures at body temperature

Thermodynamic and compressibility studies together with biological studies play an important role in the effective design and development of drug. In the current study, various drug-molecular interactions have been studied from thermophysical properties. The experimental density(ρ) and speed of sound(u) measurements for anti-diabetic drug Metformin hydrochloride (M.HCl) in binary as well as in ternary mixtures have been reported within the concentration range of 0.03–0.15 mol.kg−1 at various temperatures (305.15, 310.15 and 315.15 K) and atmospheric pressure. Various parameters like apparent molar volume of solute (Vϕ) and apparent molar compressibility of solute (KS,ϕ), limiting apparent molar volume of solute (Vϕ0), limiting apparent molar compressibility of solute (KS,ϕ0) and hydration number (nh) have been measured for binary (M.HCl + water) as well as ternary (M.HCl + Sucrose + Water) systems systematically using the experimentally measured ρ and u data. Further transfer volume (ΔtrVϕ0) of M.HCl from water to aqueous sucrose solutions have been measured at different temperatures. The hydration behavior of M.HCl has been understood from the obtained values of hydration number for studied systems at various temperatures. All the experimental results have been analysed in the light of various interactions among molecules of solvent and solute respectively.

Investigations of solute–solvent interactions in aqueous solutions of amino acids ionic liquids having the common nitrate as anion at different temperatures

Amino acids ionic liquids (AAILs) have huge potential applications in the green chemistry, as these are synthesized from the naturally occurring 20 amino acids and having strong hydrogen bonding ability, hydrophobic tuning, biodegradability, low-toxicity. These specialities are useful for the solubilization and stabilization of biomolecules in aqueous solutions and biofluids. We realize that the buffering capacity of such ionic salts in biofluids may cause some–sort of control in biological processes. It is expected that similar to carbonate–bicarbonate equilibria, the interaction of amino acids may be contributing to ionic interactions. In the present work, we report the synthesis of amino acids–based nitrate protic ionic liquids involving an infrequently used cations amino acids such as glycine ([HOOC–CH2–NH3]+) and ւ–alanine ([HOOC–(CH3)CH–NH3]+) with common inorganic planner anion as nitrate ([NO3]−). To understand the ionic and molecular interactions between the new class of solvents so called “bio–ionic liquids” such as glycine nitrate ([HOOC–CH2–NH3]+ [NO3]−) and ւ–alanine nitrate ([HOOC–(CH3)CH–NH3]+ [NO3]−) in aqueous solutions, the density property has been measured in the concentration range of 0.01974–0.52080 mol·kg−1 at different temperatures (288.15–308.15 K in steps of 5 K) and at 0.1 MPa. Further, experimental density data were used to calculate the apparent molar volume (Vϕ) of solute, partial molar volume of solute (V¯2) and partial molar volume of solvent (V¯1) as a function of concentration at 288.15–308.15 K. Using the appropriate thermodynamic equations incorporating the corrections due to Debye–Hückel limiting law, the apparent molar volume of solute at infinite dilution (Vϕ0) at all studied temperatures has been calculated along with the deviation parameters. The isobaric expansivity coefficient (α) and apparent molar expansivity (Eϕ) of solute at finite concentrations as well as limiting apparent molar expansivity (Eϕ0) of solute are also obtained at 293.15, 298.15 and 303.15 K. The results have been discussed to obtain information about the ion–solvent and ion–ion interactions along with influence of hydrophobic group on the volumetric properties.

Investigation of the thermodynamic and compressibility properties of antihypertensive drug Hydralazine hydrochloride in aqueous and aqueous amino acids solutions at various temperatures

In present communication we report experimental density and speed of sound data for the antihypertensive drug Hydralazine hydrochloride in water and 0.05 mol.kg−1 L-alanine and L-valine aqueous solutions at temperatures 293.15, 298.15, 303.15, 308.15 and 313.15 K within the molality range of 0.06–0.15 mol.kg−1. By using the experimental density and speed of sound data and appropriate equations, we calculate the parameter like apparent molar volume of solute(Vϕ), limiting apparent molar volume of solute (Vϕ0), apparent molar expansivity(Eϕ), isobaric expansivity coefficient (α), limiting apparent molar expansivity(Eϕ0), isentropic compressibility(Ks), apparent molar isentropic compressibility of solute(KS, ϕ) apparent molar isentropic compressibility at the infinite dilutions(KS, ϕ0), and hydration number(nh). The limiting apparent molar volume of solute has been used to obtain transfer parameter for Hydralazine hydrochloride. The hydration behavior for the experimental studied drug in the different mediums has been understood by computing the hydration number.

Investigation of the effect of temperature on aggregation behaviour and thermodynamic properties of Ornithine monohydrochloride in aqueous and aqueous dextrose and urea solutions

In this communication for the first time, we report the density ρ and speed of sound u of aqueous solution of Ornithine monohydrochloride (Ornithine·HCl) and Ornithine monohydrochloride (Ornithine·HCl) in aqueous 0.06 mol·kg−1 urea and aqueous 0.06 mol·kg−1 dextrose 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. From the experimental data of density (ρ) and speed of sound (u) the various derived parameters such as 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*), second derivative of limiting apparent molar volume ∂2Vϕ0/∂T2, isentropic compressibility κs, apparent molar compression (Ks,ϕ), limiting apparent molar compression of solute KS,ϕ0, apparent molar isentropic compression of transfer ΔtrKS,ϕ0 and hydration number (nH) have been calculated.

Thermophysical properties of switchable-hydrophilicity solvent systems: N,N-Dipropyl-1-propanamine, water and carbon dioxide

Measurements of density, viscosity, refractive index and conductivity of a switchable hydrophilicity solvent (SHS) system (N,N-dipropyl-1-propanamine (TPA), water, and carbon dioxide) have been carried at (283.15–308.15) K and 0.1 MPa. The derived parameters, such as apparent molar volume of solute, limiting apparent molar volume of solute, Masson’s coefficient SV, molar refraction and limiting molar conductivity, were obtained using the density, refractive index and conductivity results. Viscosity results are used to calculate the Jones-Dole viscosity B-coefficient, free energy of activation of the solute and solvent, activation enthalpy, and activation entropy. A detailed insight into the physicochemical interactions occurring among solute and solvent molecules along with the structure-making/structure-breaking tendency has been retrieved through the perusal of these calculated parameters.

What is the taste of vitamin-based ionic liquids?

The detailed volumetric and viscometric investigation of three vitamin-based ionic liquids (ILs): cholinium biotinate ([Ch][Biot]), cholinium ascorbate ([Ch][Asc]) and cholinium nicotinate ([Ch][Nicot]), have been performed in this article in order to get insight about the taste of ILs. The apparent molar volume of solute (Vϕ), apparent molar volume at infinite dilution (Vϕo), viscosity B-coefficients and hydration numbers were calculated to understand structuring of water in the aqueous solutions of investigated ionic liquids. It was found that studied ILs act as the structure promoters. Additionally, molecular dynamics simulations and DFT calculations were applied for detailed investigation of interactions in the mentioned systems. The bitter taste behaviour was discussed from calculated values of apparent specific volume and intrinsic viscosity. Results obtained by molecular docking confirmed that docking position is more responsible for bitter taste behaviour than the binding strength to receptor TAS2R38.

Molecular interactions of sodium salicylate in physiological media under the influence of electrolyte/non-electrolyte at different temperatures: Volumetric and acoustic study

Drug interactions in presence of co-solute in aqueous solution have always created an interest in the mind of chemists. The physical properties give an idea of types of interactions taking place in aqueous solution. Volumetric and compressibility are the important physical properties. Keeping this in mind we have measured the densities (ρ) and speeds of sound (u) of sodium salicylate (NaSl) drug (0.01–0.1) mol·kg−1 in 0.06mol·kg−1 aqueous sodium chloride solution and 0.06mol·kg−1 myo-inositol asa function of temperature at T=(288.15, 298.15 and 308.15) K and atmospheric pressure. These values have been used to estimate the apparent molar volume of solute (Vϕ), apparent molar isentropic compressibility (κs) of solution and apparent molar isentropic compressibility (κϕ) of solute. The limiting apparent molar expansivity (Eϕ0) of solute and coefficient of thermal expansion (α∗) of sodium salicylate in aqueous binary and ternary solutions have also been obtained. Limiting values of apparent molar volume of solute (Vϕ0) and apparent molar compressibility of solute (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 sodium salicylate from water to 0.06mol·kg−1 aqueous solutions of sodium chloride and myo-inositol at different temperatures. The co-sphere overlap model is used to interpret the values of (ΔtrVϕ0)and (Δtrκϕ0). The Helper’s constant has been obtained. It indicates structure making ability of sodium salicylate in aqueous as well as in 0.06mol·kg−1 aqueous sodium chloride and 0.06mol·kg−1 aqueous myo-inositol solutions. The results obtained have been interpreted in terms of various interactions taking place among solute and solvent molecules.

Influence of d-glucose on solvation behavior of Bis C3 (mim) Br2

In this work, experimental densities (ρ), speeds of sound (u) and relative viscosities (ηr) of DIL i.e. 1, 1-(propane-1, 3-diyl)-bis (3-methyl-1H-imidazolium-1-yl) dibromide or Bis C3 (mim) Br2 in aqueous solution 0.1molkg−1 of d-glucose as a function of concentration have been measured at T/K=(293.15, 298.15, 303.15, 308.15 and 313.15). From these experimental data, thermodynamic and transport functions such as apparent molar volume (Vϕ) of solute, limiting apparent molar volume of solute (Vϕ0), isentropic compressibility(κs), apparent molar isentropic compressibility (κϕ) of solute, limiting apparent molar compressibility of solute (κϕ0), limiting apparent molar expansivity (Eϕ0) of solute, thermal expansion coefficient(α∗), Jones-Dole viscosity coefficientsA, Β, D variation of viscosity Βcoefficient with temperature i.e. dΒ/dT, hydration number of DIL in water and in aqueous solutions of d-glucose have been calculated. Transfer volumesΔtrVϕ0 and transfer compressibilities Δtrκϕ0 of DIL from water to aqueous solutions of d-glucose at different temperatures have also been obtained. The results obtained have been interpreted in terms of various interactions taking place among solute and solvent molecules.

Volumetric and viscometric study of thiamine hydrochloride, pyridoxine hydrochloride and sodium ascorbate at T = (275.15, 277.15 and 279.15) K in dilute aqueous solutions

This paper presents data for density (ρ) and relative viscosity (ηr) measurements of aqueous solutions of thiamine hydrochloride, pyridoxine hydrochloride and sodium-L-ascorbate in dilute solutions (0–0.1) mol·kg−1 at three different temperatures, T=(275.15, 277.15 and 279.15)K and at 101.3kPa. Density results have been used to calculate apparent molar volume of solute (Vϕ), limiting apparent molar volume of solute (Vϕ0), limiting apparent molar expansivity of solute (Eϕ0), (∂2Vϕ0/∂T2) and coefficient of thermal expansion (α∗). Calculated viscosity values have been correlated according to Jones-Dole equation to obtain Falkenhagen coefficient A, Jones-Dole viscosity B-coefficient, temperature derivative of B-coefficient i.e.(dB/dT) and hydration number (nH). Free energy of activation for viscous flow per mole of solvent (Δμ10#), per mole of solute (Δμ20#), entropy of activation per mole of viscous flow of solution (TΔS20#) and enthalpy of activation (ΔH20#) have also been computed through B-coefficient. These significant parameters have been discussed in terms of different molecular interactions.

Physicochemical study of solute-solute and solute-solvent interactions of aqueous binary mixtures of l-alanine methyl ester hydrochloride and l-valine methyl ester hydrochloride at different temperatures: Volumetric and compressional studies

Amino acids are the building blocks of proteins and their study provides important information, which can be related to the behavior of larger biomolecules such as proteins. The present article reports experimental values of density (ρ) and speed of sound (u) of aqueous binary mixtures of biologically important amino acid derivatives, namely, l-alanine methyl ester hydrochloride and l-valine methyl ester hydrochloride at different temperatures i.e. T=(278.15, 288.15 and 298.15)K within the concentration range of (0–0.16)mol·kg−1. The obtained data of densities and speeds of sound of solutions were processed to obtain different derived parameters, such as apparent molar volume of solute (Vϕ), isentropic compressibility of solution (κs) and apparent molar isentropic compressibility of solute (κϕ). The limiting values of apparent molar volume of solute (Vϕ0), apparent molar isentropic compressibility of solute (κϕ0), apparent molar expansivity (Eϕ0) of solute, coefficient of thermal expansion (α∗), hydration number (nH) and second derivative of limiting apparent molar volume (∂2Vϕ0/∂T2) have also been computed. The results have been interpreted in terms of various interactions occurring among solute and solvent molecules and structure making and structure breaking tendencies of the solute in these aqueous binary systems.

Solvation behaviour of an antihelmintic drug in aqueous solutions of sodium chloride and glucose at different temperatures

The experimental values of densities (ρ), speeds of sound (u) and relative viscosities (ηr) of piperazine citrate in aqueous solution and in 0.06mol·kg−1 of sodium chloride and d-glucose as a function of concentration have been obtained at T/K=(293.15, 303.15 and 313.15). The thermodynamic parameters such as apparent molar volume (Vϕ) of solute, isentropic compressibility (κs), apparent molar isentropic compressibility (κϕ) of solute, piperazine citrate in water and in aqueous solutions of sodium chloride and d-glucose have been computed using the density and speed of sound data. The limiting apparent molar volume of solute (Vϕ0), limiting apparent molar compressibility (κϕ0) in binary and ternary solution have been obtained using apparent molar volume and apparent molar compressibility data. The limiting apparent molar expansivity (Eϕ0) of solute and thermal expansion coefficient (α∗) in both aqueous binary and ternary solutions has been computed. Transfer volumes (ΔtrVϕ0) and transfer compressibilities (Δtrκϕ0) of piperazine citrate from water to aqueous solutions of sodium chloride and d-glucose at different temperatures have been obtained. The Jones-Dole viscosity coefficients A, B, D, variation of viscosity B coefficient with temperature i.e. dB/dT, hydration number for aqueous solutions of piperazine citrate and in aqueous solutions of sodium chloride and d-glucose have been determined. The above parameters have been used to throw light on the various interactions occurring between binary and ternary systems.

Volumetric Properties of Alkyltrimethylammonium Bromides in Aqueous Solutions

Density data of good precision for binary aqueous solutions containing salt of a homologous series of alkyltrimethylammonium bromides [hexyl (C6TAB), octyl (C8TAB), decyl (C10TAB), dodecyl (C12TAB), tetradecyl (C14TAB), and hexadecyl (C16TAB)] at 293.15, 298.15, and 303.15 K are reported. Using the density data, the apparent molar volumes of solutes at finite concentration (ϕV) and at infinitely dilute solutions (ϕV0) have been calculated. The partial molar volumes (V2), apparent molar expansivity (ϕE) and limiting molar expansivity (ϕE0) parameters at 298.15 K are also reported. The pseudophase separation model has been utilized to estimate critical micelle concentration (cmc) and aggregation number (n) of the studied surfactant molecules. The main result of our studies is the observation that the expansivity parameter goes through a maximum at cmc except in the case of C6TAB and C8TAB surfactants at 298.15 K. The volume changes due to micellization (ΔVxmic) and standard unitary free energy changes for ...

Studies on molecular interactions of some neurotransmitters in water using volumetric and compressibility measurements at T = (278.15, 288.15 and 298.15) K

The systematic measurements of densities (ρ) and speeds of sound (u) of aqueous binary mixtures of bioactive amino acid neurotransmitters viz. gamma amino butyric acid, glycine hydrochloride and sodium glutamate at different temperatures i.e. T=(278.15, 288.15 and 298.15)K within the concentration range of (0.05 to 0.35)mol·kg−1 have been carried out. The obtained data of densities and speeds of sound were used to calculate different derived parameters such as apparent molar volume of solute (Vϕ), isentropic compressibility of solution (κs) and apparent molar isentropic compressibility of solute (κϕ) of gamma amino butyric acid, glycine hydrochloride and sodium glutamate in water at different temperatures. The limiting values of apparent molar volume (Vϕ0) of solute, apparent molar isentropic compressibility (κϕ0) of solute and apparent molar expansivity (Eϕ0) have also been obtained. The coefficient of thermal expansion (α∗), second derivative of limiting apparent molar volume (∂2Vϕ0/∂T2) and hydration number (nH) of the water soluble neurotransmitters have also been computed. The results have been interpreted in terms of various interactions among solute and solvent molecules such as hydrogen bonding, (solute+solute) and (solute+solvent) interactions and structure making and structure breaking tendencies of the solutes in water. The scaled particle theory has been used to interpret volumetric results.