Values Of Partial Molar Volumes Research Articles

Volumetric Properties of Aqueous Sodium Salt of Amino Acids as CO2 Capture Solvent

Objectives: To produce new and accurate data of density of aqueous solution of amino acid salts at different temperatures and to correlate it with molality. Methods: The densities of aqueous solutions of sodium salts of Amino acids such as L-cysteine, L-leucine, L-proline and L-valine have been measured using double-arm Pycnometer, placed in a transparent glass-walled water bath having thermal stability of (0.01 K) at concentrations range (0.01 to 0.15) mol L-1 and at 298.15, 303.15, 308.15, and 313.15 K. From density data ahead, apparent molar volumes (Vϕ ), the partial molar volumes (Vϕ 0), expansion coefficient (E¥) and Hepler’s constant ( ¶ 2Vϕ 0=¶ T2) were calculated and analysed on the basis of the intermolecular interaction and molecular structure. Findings: The densities are observed to increase with concentration and decrease with increasing temperature. The positive values of partial molar volume (Vϕ 0) indicate strong sodium amino acids -water interactions. Novelty: For studied aqueous sodium salt solution of Amino acids, such properties have not yet been reported in the open literature and at such a lower concentrations range (0.01 to 0.15) mol L-1. Keywords: Density; Sodium Salt Amino Acid; Apparent Molar Volume; Helper’s Constant

The study of intermolecular interactions in [Bmim][PF6] + 1-octyl-2-pyrrolidone binary mixtures from volumetric, acoustic, optical and spectroscopic measurements

Under 101.3 kPa pressure, the densities, speeds of sound, and refractive indices of [Bmim][PF6] + 1-octyl-2-pyrrolidone mixtures were determined experimentally over the whole composition range and at 303.15 to 323.15 K. The excess molar volumes (VmE), excess values of partial molar volumes (V¯mE), partial molar volumes at infinite dilution (V¯mE,∞), excess values of isentropic compressibility (KsE), speeds of sound (uE) and isobaric thermal expansion coefficient (αPE) have been calculated using these experimental data. The Redlich–Kister polynomial equation has been adequately fitted to the computed data. Intermolecular interactions between like and unlike molecules have been interpreted using the experimental and computed data. The Prigogine–Flory–Patterson theory of excess molar volume and IR spectroscopic studies supported the conclusions drawn from volumetric and acoustic properties.

Volumetric and spectroscopic properties of binary liquid mixtures of isopentyl alcohol with butylamine at T = (288.15–333.15) K

The current article presents the experimental density (ρ) values reported as a function of mole fraction for the binary liquid mixtures of isopentyl alcohol (IPA) + butylamine (BA) at the temperatures T = (288.15 to 333.15) K with 5 K intervals under atmospheric pressure (0.1 MPa). Based on experimental data, the molar volume (Vm), excess molar volume (VmE), apparent molar volumes (Vm,∅,1and Vm,∅,2), partial molar volumes (V-m,1and V-m,2), and excess partial molar volumes (V-m,1E and V-m,2E) values were computed over the complete mole fraction range. Also, at infinite dilution, the values of partial molar volumes (V¯m,1° and V¯m,2°), and excess partial molar volumes (V¯m,1°E and V¯m,2°E) of the isopentyl alcohol and butylamine were calculated. The calculated VmE values were correlated to the Redlich-Kister (R-K) model. Further, the excess molar volume was theoretically described by using Prigogine-Flory-Patterson (PFP) theory at the above temperatures. The obtained excess molar volume shows negative deviations from the ideal behaviour and becomes more negative at a higher temperature. From the above said parameters results, the H-bonding and acid-base interactions in the unlike molecules was determined. Additionally, the existence of new H-bonding interaction between IPA and BA molecules was further confirmed using 1H NMR and FT-IR spectroscopic studies.

Volumetric and aggregation properties of metformin hydrochloride in methanol in temperature range of (288.15–318.15) K

This manuscript is related to the study of volumetric and micellar properties of metformin hydrochloride (Met-HCl) in methanol in temperature range of (288.15–318.15) K. Conductometric and refractive index data was used to find CMC of drug. From conductometric data various thermodynamic variables were calculated which include free energy of micellization, entropy of micellization and enthalpy of micellization. Density measurements of different drug solutions at specified temperatures were utilized for the calculation of apparent molar volume, partial molar volume, Hepler's constant and partial molar expansivity. These parameters are important for getting an understanding about different types of interaction of drug in solution. Met-HCl showed strong solvophobic than electrostatic interaction with methanol and had a structure promoting effect on it which was apparent from positive value of partial molar volume, Hepler's constant and partial molar expansivity. Micellization process was spontaneous, endothermic and resulted in increase in entropy of system because Gibbs energy change was negative, enthalpy change and entropy changes were positive.

Molecular interactions studies of doxycycline hyclate in water, aqueous L-phenylalanine and glycyl glycine at different temperatures by using volumetric, ultrasonic and viscometric parameters

The density, sound velocity and viscosity of doxycycline hyclate in water, aqueous solution of L-phenylalanine and aqueous solution of glycyl glycine have been determined at different temperatures (305.15, 310.15, 315.15 and 320.15) K. The calculated values of partial molar volume (V_ϕ^o), standard partial molar volume of transfer (〖Δ_tr V〗_ϕ^o), partial molar adiabatic compressibility (κ_(ϕ,s)^o) and partial molar adiabatic compressibility of transfer (〖Δ_tr κ〗_(ϕ,s)^o) for doxycycline hyclate in water, aqueous solution of L-phenylalanine and aqueous solution of glycyl glycine infer the dominance of ion-hydrophilic interactions over hydrophobic-hydrophobic interactions. The Jones-Dole viscosity B-coefficient, viscosity B-coefficient of transfer (ΔtrB), free energy of activation of viscous flow per mole of pure solvent (〖Δμ〗_1^(o*)) and solute (〖Δμ〗_2^(o*) ), respectively, activation entropy (〖ΔS〗_2^(o*)) and activation enthalpy (〖ΔH〗_2^(o*)) of doxycycline hyclate in water, aqueous solution of L-phenylalanine and aqueous solution of glycyl glycine also have been calculated using viscosity data. The structure making and breaking behaviour of doxycycline hyclate in water, aqueous solution of L-phenylalanine and aqueous solution of glycyl glycine are obtained from the values of Hepler’s constant i.e.((δ^2 V_ϕ^o)/(δT^2 )) and (dB/dT). The presence and absence of caging effect has been studied with the help of partial molar adiabatic expansibility (E_ϕ^o). The isobaric thermal expansion coefficient (α^o= (E_ϕ^o)/(V_ϕ^o )), intermolecular free length and acoustic impedance for doxycycline hyclate in water, aqueous solution of L-phenylalanine and aqueous solution of glycyl glycine also have been determined.

Temperature-dependent physicochemical studies of some glycols in aqueous d-mannitol solution

The interlinkage of ethylene glycol, diethylene glycol and triethylene glycol with d-mannitol at different values of temperature has been analysed by the combination of volumetric and acoustic process. Different values of speed of sound and the density of EG, DEG and TEG in the molalities of (0.01, 0.03 and 0.05) mol kg−1 in aqueous solutions of d-mannitol at T = (293.15, 298.15, 303.15 and 308.15) K have been considered. From the values of speed of sound, the partial molar isentropic compression (Kϕ,s) and the partial molar isentropic compression of transfer $$(\Delta {\rm K}_{{\phi ,{\text{s}}}}^{0}$$ ), have been determined. The pair and triplet interaction coefficient have also been estimated. From the density data, the apparent molar volume $$(V_{\phi }^{0}$$ ) and standard partial molar volume of transfer $$(\Delta V_{\phi }^{0} )$$ for EG, DEG and TEG in aqueous d-mannitol solutions have been examined. Using the values of partial molar volume and partial molar isentropic compression of transfer, the pair and triplet coefficients are determined. These noteworthy parameters are helpful to examine the interactions between sugar alcohol + glycols + water solutions.

Unraveling the binding and micellization behavior of dioctylsulfosuccinate Sodium Salt with vitamin B1 and B6: A physiochemical and computational study

The outcomes of drug delivery rely on the route of administration which further depends on the understanding of interactional or partitioning mechanism of drugs within the self assembled structures. Thus, identification of various interactions in such systems is of utmost importance. Herein, the partitioning of vitamins: B1 (thiamine hydrochloride; THC) and B6 (Pyridoxine hydrochloride; PyH) in dioctyl sulfosuccinate sodium salt (AOT) have been addressed by employing experimental and computational techniques. The values of partial molar volumes (ΔtrV2,фo) and partial molar isentropic compressions ΔtrKS,2,фo of transfer for PyH have been calculated from density and sound velocity measurements which suggest the presence of hydrophilic interactions between AOT and PyH. The obtained results were further supported by Density Functional Theory Calculations which suggest that hydrogen bonding plays important role in PyH/AOT binding. The binding constants along with thermodynamic parameters at different temperatures have been calculated using calorimetric measurements. In case of THC/AOT the negative values of ΔrS are overcome by more negative values of ΔrH, making the overall process favorable. In case of PyH, two set of binding sites with stronger affinity for second site have been observed along with favorable entropy. Calorimetric and surface tension measurements were used to study the impact of PyH/THC on the Critical micelle concentration of AOT. Spectroscopic and Dynamic light scattering studied have been used as complementary techniques that also confirmed the partitioning of vitamins in AOT micelles.

Excess volume, isothermal compressibility, isentropic compressibility and speed of sound of carbon dioxide+n-heptane binary mixture under pressure up to 70 MPa. II. Molecular simulations

Molecular simulations have been performed in this work to provide a microscopic understanding of the experimental results of asymmetric supercritical binary mixtures of carbon dioxide and n-heptane published in the first article of the series [Bazile et al. J. Supercrit. Fluids 140, 218 (2018)]. Interestingly, molecular simulations results compared well with experimental data on density, isothermal compressibility, speed of sound, isentropic compressibility and the corresponding excess properties. In addition, using Kirkwood-Buff theory, computed partial molar volumes are found to be consistent with those obtained indirectly from experimental data. In particular, the negative value of partial molar volume of n-heptane at infinite dilution close to CO2 critical conditions is well captured, confirming the occurrence of a clustering phenomenon at such conditions. Last, computed properties of the cluster indicates a weak cluster with a radius of about 3 nm and a residence time of the CO2 molecules in the cluster of about 25 ps.

Thermo-physical and spectroscopic studies of liquid mixtures containing p-methoxy benzoic acid

ABSTRACT The density and speed of sound were measured for p-Methoxy benzoic acid (P-MBA) with Aniline, N-Methylaniline (NMA) and N, N-dimethylaniline (NNDMA) from (303.15 K–313.15 K) with 5K interval temperatures using standard techniques. Thermo physical properties of molar volume (Vm ), acoustic impedance (Z), isentropic compressibility (κs ), surface tension (σ) and free length (Lf ) and their excess properties were intended from measured data. These excess parameters have been fitted to the Redlich–Kister type polynomial equation using the least square method. Obtained values of partial molar volumes ( , ) reflects the culminations were drawn from Vm E. Supplementary, to test the pertinent of different theoretical models of speed of sound by means of resoluted values. Finally, the formation of hydrogen bonding between molecules in composition was fetched from FTIR spectra.

Spectroscopic and volumetric study of binary liquid mixtures containing Ethyl -4-hydroxy benzoate and alkanols

Abstract The Speed of sound and density values for mixtures of Ethyl – 4 - hydroxy benzoate (E- 4- HB) with alkanols were measured at 303.15 K, 308.15 K and 313.15 K. From these experimental values, thermoacoustic properties like isentropic compressibility (Ks), molar volume (Vm), free length (LfE) and their excess parameters have been calculated. These excess parameters have been fitted to the Redlich–Kister type polynomial equation using the least square method. The values of partial molar volumes (V m, 1, V m,2)and infinite dilution (V∞m,1, V∞m,2) were estimated from molar volume (Vm). Further, the infrared spectra for all systems have been recorded to analyze and examine various stretching's present in the mixture. The digressions of the mixture were explained based on intra/ inter molecular relations among dissimilar molecules present in the system.

An experimental investigation of molecular interactions between [Emim][triflate] ionic liquid & 2-alkoxyethanols and theoretical comparison by PFP theory

Physical properties, such as density (ρ) and speed of sound (u) of 1-ethyl-3-methylimidazolium trifluoromethanesulfonate, 2-ethoxyethanol/2-propoxyethanol and their binary mixtures are measured over the whole composition range as a function of temperature between 298.15 K and 318.15 K at atmospheric pressure. Experimental values were used to calculate the excess molar volumes (VmE), excess values of partial molar volumes (V¯mE), excess values of isentropic compressibility (κsE), free length (LfE), speeds of sound (uE) and isobaric thermal expansion coefficient (αPE) for the binary mixtures. These excess properties were fitted to the Redlich-Kister type equation to obtain the binary coefficients and the standard deviations. A qualitative analysis of these parameters indicates the interaction decreases with the increase in chain length. This was further supported by Prigogine–Flory–Patterson (PFP) theory of excess molar volume.

Thermodynamics of aqueous solutions of ionic liquids composed of [BMPYR] or [BMIM] cations and tetraflate or dicyanamide anions

Abstract This paper explores the thermodynamic behavior of aqueous solutions of four ionic liquids (ILs), namely 1-butyl-1-methylpyrrolidinium dicyanamide [BMPYR][DCA], 1-butyl-3-methylimidazolium dicyanamide [BMIM][DCA], 1-butyl-1-methylpyrrolidinium 1,1,2,2-tetrafluoroethanesulfonate [BMPYR][TFES], and 1-butyl-3-methylimidazolium 1,1,2,2-tetrafluoroethanesulfonate [BMIM][TFES]. The ionic liquids with [TFES] – anion (tetraflates) have been scarcely researched so far and therefore were characterized here with 1 H NMR spectroscopy and DSC calorimetry. In all four systems studied, water activity was systematically measured, the determinations being carried out in the whole composition range and at seven temperatures in the range from 288.15 K to 318.15 K. In addition, the mixing enthalpies in the IL dilute region for (water + DCA IL) systems and the solid-liquid equilibria for (water + TFES IL) systems were experimentally determined. The dependences of activity coefficients on temperature and composition were correlated ( i ) separately with appropriate flexible equations and ( ii ) simultaneously with an extended NRTL model. Both correlation approaches provide adequate description of mixture energetics and, as documented by comparisons with other relevant data, allow extrapolations of activity coefficients to both higher and lower temperatures as well as good predictions of excess enthalpy. Furthermore, the volumetric and viscosity behavior of highly dilute solutions of the ILs was explored. The concentration dependences of the apparent volume and viscosity were fitted well by the respective classical Redlich-Meyer and Jones-Dole equations. The values of partial molar volumes at infinite dilution were found to perfectly obey the ion additivity and correlate well with the intrinsic volume of IL molecule. Thermodynamic behavior of studied systems was compared to each other and discussed with respect to molecular interactions and nanostructure as well as to how involved ions affect it.

Thermophysical properties of 1-butyl-3-methylimidazolium bis (trifluoromethylsulfonyl) imide with 2-ethoxyethanol from T = (298.15 to 323.15) K at atmospheric pressure

Density (ρ) and speed of sound (u) data is determined for various binary compositions of 1-butyl-3-methylimidazolium bis (trifluoromethylsulfonyl) imide ([Bmim][NTf2]) and 2-ethoxyethanol (2EE) at different temperatures. The experimental data of density and speed of sound is used to calculate the values of excess molar volume, excess isentropic compressibility, excess intermolecular free length and excess speed of sound. The variations in these parameters are analysed to understand the nature of molecular interactions between the chemical species. Redlich-Kister equation is used to estimate the deviations between the calculated and experimental excess values. The values of partial molar volume, excess partial molar volume and excess partial molar volume at infinite dilution have been calculated. The trends of variation of these properties have been interpreted in light of the solute-solvent interactions occurring in the system. Further, the experimental FT-IR analysis is used to study the interactions between the chemical species.

Speed of sound and density of water + 1,5-pentanediol mixtures in a wide temperature range. Comparison with mixtures of water with diethylene glycol, propoxyethanol and diethylene glycol dimethyl ether

Densities (ρ) and speed of sound (u) were measured in the binary liquid mixture of water and 1,5-pentanediol (PD) over the entire mixture composition range. Densitometric measurement were conducted in a temperature range of 278.15–333.15K under atmospheric pressure, using a precise sealed vibrating-tube densimeter. Acoustic study was carried out in a range of 288.15–318.15K. The values of molar volume (Vm), adiabatic compressibility coefficient (βs), temperature coefficients of these parameters, excess of compressibility coefficient (βsE), excess molar volume (VmE) and derivatives (∂H/∂p), (∂S/∂p) and (∂Cp/∂p) were determined from the experimental data. The values of molar volume were used to determine the values of partial molar volumes of the mixture components. Changes in the measured and calculated values of the physicochemical parameters as a function of temperature and composition of the mixture were analysed in terms of interactions in two-component systems. The obtained results were compared with those received in our earlier investigations of the mixtures of water with diethylene glycol and propoxyethanol as well as with those found in the literature survey concerning water–diethylene glycol dimethyl ether mixtures.

Critical evaluation of partial molar volumes and excess partial molar volumes of molten fluoride melts

Different procedures of evaluation of partial molar volume and excess partial molar volume have been applied for three binary or quasi-binary molten fluoride systems: KF–K2TaF7, K2ZrF6–K2TaF7 and (LiF–NaF–KF)eut–K2ZrF6. In the first procedure partial molar volume is calculated based on mathematical fitting of molar volume, while in the second procedure partial molar volume is calculated based on mathematical fitting of excess molar volume. It was shown that both procedures are in principle consistent. However, some inconsistencies on values of partial molar volume can occur when local extremes are observed on concentration dependence of molar volume. In such situation, proper selection of mathematical functions is essential which requires relatively high density of experimental data. Moreover, when data on only restricted concentration range are available, only procedure of molar volume fitting is applicable for calculation of partial molar volume.

The study of solute–solvent interactions in 1-ethyl-3-methylimidazolium ethylsulfate + 2-ethoxyethanol from density, speed of sound and refractive index measurements

Physical properties, such as density (ρ), speed of sound (u) and refractive index (nD) for pure [Emim][EtSO4], 2-ethoxyethanol and their binary mixtures are measured using Anton Paar vibrating tube density, sound velocity meter (DSA 5000M) and automatic refract meter over the whole composition range as a function of temperature between (298.15–328.15)K at atmospheric pressure. Experimental values were used to calculate the excess molar volumes (VmE), excess values of partial molar volumes (V̅mE), partial molar volumes at infinite dilution (V̅mE,∞), excess/deviation values of isentropic compressibility (κsE), isothermal compressibility (κTE), free length (LfE), speed of sound (uE), refractive index (ΔϕnD), internal pressure (πiE), free volume (VfE) and isobaric thermal expansion coefficient (αPE) for the binary mixtures. These excess/deviation properties were fitted to the Redlich–Kister type equation to obtain the binary coefficients and the standard deviations. A qualitative analysis of these parameters indicates strong intermolecular interactions between the liquids in study. This was further supported by IR spectroscopy.

Acoustic and volumetric studies on water + diethylene glycol mixtures in a wide temperature range. Comparison with mixtures of water with tri- and tetraethylene glycol

Densities (ρ) and sound velocity (u) were measured in the binary liquid mixture of water and diethylene glycol-water (DEG) over the entire mixture composition range. Density values were recorded in a temperature range of 278.15–333.15K under atmospheric pressure, using a precise sealed vibrating-tube densimeter. Sound speed values were recorded in a range of 288.15–318.15K. The values of molar volume (Vm), adiabatic compressibility coefficient (βs), temperature coefficients of these parameters, excess of compressibility coefficient (βsE), excess molar volume (VmE) and derivatives (∂H/∂p), (∂S/∂p) and (∂Cp/∂p) were determined from the experimental data.The values of molar volume were used to determine the values of partial molar volumes of the mixture components. Changes in the values of physicochemical parameters measured and calculated as functions of composition and temperature were analyzed in the aspect of intermolecular interactions in two-component systems. The results obtained were compared with the results of similar studies of the mixtures of water and tri- and tetraethylene glycols.

Acoustic and volumetric studies on (triethylene glycol + water) mixtures in a wide temperature range

The sound velocity (u) and density (ρ) have been measured in binary liquid mixture of water and (triethylene glycol+water) (TEG) over the entire mixture composition range. Density values were recorded in a temperature range of (278.15 to 333.15)K, while speed of sound values were recorded in a range of T=(288.15 to 318.15)K. The values of molar volume (Vm), adiabatic compressibility coefficient (βs), temperature coefficients of these parameters, excess of compressibility coefficient (βsE), excess molar volume (VmE) and derivatives (∂H/∂p), (∂S/∂p) and (∂Cp/∂p) have been determined from the experimental data.The values of molar volume were used to determine the values of partial molar volumes of the mixture components. Changes in the values of physicochemical parameters measured and calculated as functions of composition and temperature were analysed in the aspect of intermolecular interactions in two-component systems.

Choice of the center of water molecules in calculations of partial molar volume of single ions immersed in water: A molecular simulation study

In the Kirkwood–Buff theory, the center of each solvent molecule can be arbitrarily chosen. However, this arbitrariness is not obvious in the calculation of the Kirkwood–Buff integral for a single ion. Actually, the Kirkwood–Buff integral depends on the choice of the center of a solvent molecule, if each solvent molecule has a dipole moment and the solute has a net charge. A few examples based on molecular dynamics simulations are shown. A surrogate definition for the center of a water molecule is also shown. A good agreement between the calculated and experimental values of partial molar volumes for single ions is observed.

On the total, apparent partial molar, partial molar, apparent partial specific and partial specific volume of the binary systems

In this article, seven relationships that have been widely used to estimate the dependence of apparent partial specific volume (APSV) with concentration are reviewed and compared with each other. Also, 10 methods to evaluate partial molar volume (PMV) were derived and compared with each other. At null concentrations the values of APMV of all relationships meet each other; therefore all of the above relationships at very low concentrations are useful and estimate values near to each other. However, as the concentration increases the differences also increase. The variation of APMV with molality or mole-fraction of solute is not linear, and therefore any line fitted to the data to get the slope and intercept to estimate PMV is visual approximation and hence it is bias. The values of PMV obtained through APMV values follow the same curvature trend as values of APMV with a positive slope. Whereas the values of PMV calculated from the slope of density versus molality fit-in a perfect straight line with negative slope (in the range of concentration studied). The appropriate concentration unit for PMV and partial specific volume (PSV) is molality, and the combined relationship is the most appropriate way to evaluate PMV. However, other concentration units such as mass per volume and weight fraction as concentration unit are also studied. It was demonstrated that when a combined relationship is used, evaluation of PMV and PSV is easier and exact. Also, the values of PMV extrapolated to zero concentration were compared with the molar volumes of solvent and solute.