Terms Of Solute-solvent Interactions Research Articles

Thermodynamic investigation of glycol ethers in aqueous sugar alcohol at multiple temperatures

Understanding the molecular dynamics and intermolecular interaction of liquid mixtures can be greatly aided by ultrasonic study. Sound speed and Density of glycols ethers (phenoxyethanol and butoxyethanol) in solutions of a well-known sugar alcohol (d-Mannitol), were measured using the AntonPaar (DSA 5000 M) at concentrations of (0.02, 0.06, and 0.10) mol.kg−1 and fixed experimental pressures (0.1 MPa) over the entire temperature range (288.15, 293.15, 298.15, 303.15) K. With the experimental data of velocity and density, a number of additional dependent basic acoustic-thermodynamic parameters, namely Vander Waal’s constant (b), intermolecular free length (Lf), acoustic impedance (Z), adiabatic compressibility (β), Rao’s constant (R), and Wada’s constant (W) have been evaluated. Through these parameters, interactions between solutes and their solvents are expressed in terms of solute-solvent interactions. Research is also done on the solute’s capacity to create or destroy structures in a solvent. The inter-molecular interactions amidst the ternary mixture of glycols ethers and d-mannitol in aqueous medium were analyzed.

The Ion-Dipole Correction of the 3DRISM Solvation Model to Accurately Compute Water Distributions around Negatively Charged Biomolecules.

The 3D reference interaction site model (3DRISM) provides an efficient grid-based solvation model to compute the structural and thermodynamic properties of biomolecules in aqueous solutions. However, it remains challenging for existing 3DRISM methods to correctly predict water distributions around negatively charged solute molecules. In this paper, we first show that this challenge is mainly due to the orientation of water molecules in the first solvation shell of the negatively charged solute molecules. To properly consider this orientational preference, position-dependent two-body intramolecular correlations of solvent need to be included in the 3DRISM theory, but direct evaluations of these position-dependent two-body intramolecular correlations remain numerically intractable. To address this challenge, we introduce the Ion-Dipole Correction (IDC) to the 3DRISM theory, in which we incorporate the orientation preference of water molecules via an additional solute-solvent interaction term (i.e., the ion-dipole interaction) while keeping the formulism of the 3DRISM equation unchanged. We prove that this newly introduced IDC term is equivalent to an effective direct correlation function which can effectively consider the orientation effect that arises from position dependent two-body correlations. We first quantitatively validate our 3DRISM-IDC theory combined with the PSE3 closure on Cl-, [ClO]- (a two-site anion), and [NO2]- (a three-site anion). For all three anions, we show that our 3DRISM-IDC theory significantly outperforms the 3DRISM theory in accurately predicting the solvation structures in comparison to MD simulations, including RDFs and 3D water distributions. Furthermore, we have also demonstrated that the 3DRISM-IDC can improve the accuracy of hydration free-energy calculation for Cl-. We further demonstrate that our 3DRISM-IDC theory yields significant improvements over the 3DRISM theory when applied to compute the solvation structures for various negatively charged solute molecules, including adenosine triphosphate (ATP), a short peptide containing 19 residues, a DNA hairpin containing 24 nucleotides, and a riboswitch RNA molecule with 77 nucleotides. We expect that our 3DRISM-IDC-PSE3 solvation model holds great promise to be widely applied to study solvation properties for nucleic acids and other biomolecules containing negatively charged functional groups.

Free energy reconstruction/decomposition from WHAM, force integration and free energy perturbation for an umbrella sampling simulation

Comparisons between methodologies are usually made by performing separated sampling simulations in conjunction with the corresponding estimator. Here, the accuracy and convergence of three typical approaches (WHAM, force integration, and FEP) for estimating the ion-pairing free energy in water are carefully examined in order to identify which estimator is the most efficient for a particular set of trajectories. The force integration is superior among these methods, whereas the FEP introduces relatively prominent uncertainty arising from the perturbed potential energy. The direct solute-solvent interaction term and the indirect solvent contribution accounting for the reorientation of non-spherically symmetric ions could be straightforwardly extracted using force integration and FEP.

Density, Viscosity and Ultrasonic Velocity of Polyethylene Glycol

Ultrasonic velocity, density, and viscosity of polyethylene glycol have been measured for the solution in water at concentration range of 0.3% to 1% at temperature 50oC. Ultrasonic velocity has been measured using ultrasonic interferometer at 1MHz frequency. By using the values of ultrasonic velocity, density, and viscosity, various acoustical parameters like adiabatic compressibility, acoustic impedance, intermolecular free length, and relaxation time have been calculated. The change in these acoustical parameters is explained in terms of solutesolvent interaction in a polymer solution.

Effect of some deep eutectic solvents based on choline chloride on thermodynamic properties of 5-hydroxymethylfurfural at T = (288.15 to 318.15) K

In recent years, 5-hydroxymethylfurfural (5-HMF) as an important intermediate in the production of added-value chemical products have been produced from the hydrolysis of carbohydrates in the new generation of green solvents named as deep eutectic solvents (DESs). In order to development, design, and optimization of the synthesis and extraction processes containing 5-HMF, the thermodynamic properties play an important role. In this work, some of the thermodynamic properties of 5-HMF in the aqueous solutions of the DES, choline chloride (ChCl) - citric acid and choline chloride – malonic acid, were investigated. The densities, viscosities, speeds of sound, and refractive indices for the systems containing 5-HMF in water and aqueous solutions of DES have been measured at T = (288.15 to 318.15) K. The data have been used to calculate the standard partial molar volumes Vφ0, partial molar isentropic compressibility Kϕ0, viscosity B-coefficients and molar refractions RD. The results have been interpreted in terms of solute-solvent interactions that these interactions were increased with increasing the concentration of DES. The transfervolumes ΔtrVφ0 show that dominant interactions between 5-HMF and DESs are ion-polar and polar-polar interactions.

Volumetric and ultrasonic studies of molecular interactions of glycols in aqueous glutaraldehyde solutions at different temperatures

In the current work, Density and speed of sound (ultrasonic speed) of liquid mixtures of (ethylene, diethylene and triethylene glycols + aqueous glutaraldehyde solutions) have been investigated at the temperature ranges of (293.15 K, 298.15 K, 303.15 K and 308.15 K) and in the concentration of (0.01, 0.02, 0.03 and 0.04) mol·kg−1. Different thermodynamic and acoustic parameters have also been calculated using density and speed of sound experimental values. Vϕ (apparent molar) and Vϕ0 (partial molar) volumes and ΔVϕ0 (partial molar volume of transfer) have been estimated using experimental values of density. Using speed of sound values, Kϕ, s (apparent molar) and Kϕ, s0 (partial molar) isentropic compressions and ΔKϕ, s0 (partial molar isentropic compression of transfer) have been obtained. Using partial molar volume of transfer and partial molar isentropic compression of transfer values, the pair and triplet interaction coefficients have also been computed. The final outcome of the research is studied in terms of solute-solvent interactions between the molecules of liquid mixtures.

Study of surface and bulk physicochemical properties of biocompatible nanoemulsions at T = (293.15,303.15 and 313.15 K)

Abstract The physicochemical properties (PCPs) such as viscosity (η), surface tension (γ), friccohesity (σ), particle size (r), zeta potential (ξ) and polydispersity along with the dispersibility and stability assessments are reported for thermodynamically and kinetically stable oil-in-water (o/w) nanoemulsions (NEs) of castor oil (CO), olive oil (OO) and linseed oil (LO) in the presence of cellulose acetate alkanoates stabilizers - cellulose acetate butyrate (CAB) and cellulose acetate propionate (CAP) with cetyltrimethylammonium bromide (CTAB), sodium dodecyl sulphate (SDS) and Tween 20 (Tw20) surfactants at T = 293.15, 303.15 and 313.15 K. The γ, η and ρ data is used to deduce excess surface concentration (Γ ), the area per molecule (Amin), particle size (r), fractional volume (ϕ), activation energy (Ea), and friccohesity (σ) values. This study highlights the role of temperature, structure of oil, surfactants, and stabilizers in the formulation, stability analysis and important physicochemical properties of NEs. Inter-molecular multiple interaction (IMMI) such as electrostatic, hydrogen bonding (HB), cohesive forces (CFs), frictional forces (FFs), Brownian motion, Van der Waals forces and London dispersion forces (LDFs) infer enhanced stability of the NEs. High surface area and biocompatibility make these NEs useful for biological and industrial applications. The measured and calculated PCPs correlate quite well with the stability of biocompatible NEs in terms of solute-solvent interactions (SLS0I) and solute-solute interactions (SLSLI).

Study on the interactions of drug isoniazid in aqueous-D-xylose/L-arabinose solutions at different temperatures using volumetric, acoustic and viscometric approaches

Volumetric, acoustic and viscometric properties of drug isoniazid in water and aqueous solutions of carbohydrates, D-xylose and L-arabinose (5% and 10% D-xylose/L-arabinose in water, w/w) were studied at various temperatures, T = (293.15–318.15) K and at atmospheric temperature. The apparent molar volumes, Vϕ and apparent molar compressibilities, Ks,ϕ were calculated from the experimentally measured densities and ultrasonic speeds. Limiting apparent molar volumes, Vϕ°, limiting apparent molar compressibilities, Ks,ϕ°, limiting molar expansibilities, Eϕ° and their corresponding transfer volumes, Vϕ,tr° and transfer compressibilities, Ks,ϕ,tr° of drug isoniazid from water to aqueous carbohydrate solutions were also evaluated. Falkenhagen Coefficients, A, Jones-Dole coefficients, B, variation of B with temperature, dB/dT, free energies of activation of viscous flow per mole of solvent, Δμ1°# and per mole of solute, Δμ2°#, enthalpies, ΔH°# and entropies, ΔS°# of activation of viscous flow were calculated from the viscosity measurements. The negative sign of dB/dT indicated the structure making ability of the drug isoniazid. The results obtained have been discussed in terms of solute-solvent interactions in order to understand the solvation behaviour of isoniazid in these aqueous-carbohydrate solutions.

Molecular interaction studies of binary systems comprising [C2mim] [BF4] with ethyl acetoacetate or benzaldehyde

In this work, new data for the binary mixtures containing 1-ethyl-3-methylimidazolium tetrafluoroborate ([C2mim] [BF4]) ionic liquid (IL) with benzaldehyde or ethyl acetoacetate were investigated under atmospheric pressure (p = 0.1 MPa) and at temperatures (293.15–313.15) K. The binary mixtures were completely miscible at all proportions. Densities (ρ), viscosities (η) as well as speeds of sound (u) were conducted across the entire range of mole fraction (xi = 0 to 1). The excess properties which include excess molar volumes(VmE), intermolecular free length (Lf), deviations in viscosity (Δη), isentropic compressibility(ks), apparent molar isentropic compressibility (Kϕ) as well as deviation in isentropic compressibility(Δks) were determined from the experimentally found results of speed of sound, viscosity and density. The obtained derived properties have been elucidated in terms of solute-solvent interactions taking place in the systems. The investigation of thermophysical properties of organic solvents with ionic liquids is essential as they decide the transformation of ionic liquids from small laboratory scale to large industrial applications. The obtained results are important and essential as they describe the molecular interactions, and can be used in constructing the structure-property correlation as well as molecular modelling that exist between [C2mim] [BF4] with benzaldehyde or ethyl acetoacetate. Redlich-Kister polynomial equation was used to fit the excess values and a good correlation was achieved.

Molecular Association Studies on Polyvinyl Alcohol at Different Concentrations

Ultrasonic velocities, densities, and viscosities have been measured for the solution of polyvinyl alcohol in water at concentration range of 0.3% to 1% at temperature 35°C. Ultrasonic velocities have been measured using variable path ultrasonic interferometer at 1 MHz frequency. The acoustical parameters like adiabatic compressibility, acoustic impedance, intermolecular free length, and relaxation time have been calculated by using above-mentioned values of ultrasonic velocities, densities, and viscosities. The variation of these acoustical parameters is explained in terms of solute-solvent interaction in a polymer solution.

Thermodynamics of solution and partition of dioxidine in water and the water/1-octanol biphasic system

We have studied for the first time the thermodynamic behavior of the well-established antimicrobial drug – dioxidine (2,3-dihydroxymethylquinoxaline-1,4-dioxide) in water and the water/1-octanol biphasic system. Enthalpies of solution and solubility of dioxidine were experimentally determined and exploited to compute thermodynamic functions of solution and the solubility of the drug in a wide temperature range. Partition coefficients between water and 1-octanol were also obtained to evaluate lipophilicity of dioxidine and used to compute thermodynamic functions of the solute transfer from water to aqueous octanol. The results are discussed in terms of solute-solvent interactions occurring in water-like and lipid-like phases.

Thermophysical characterization of aqueous deep eutectic solvent (choline chloride/urea) solutions in full ranges of concentration at T = (293.15–323.15) K

Deep eutectic solvents (DESs) as a novel generation of green solvents have been used in several processes in academia and technology in the recent years. In this study, it was measured some thermophysical properties of aqueous solutions of the deep eutectic solvents (choline chloride/urea) in full ranges concentration of DES at T=(293.15–323.15)K. The densities, speeds of sound, refractive indices, and viscosities of the investigated systems have been measured by precise methods and those results used to calculate various thermodynamic and transport properties including the excess molar volumes (VE), the partial molar volumes (V¯m,1 and V¯m,2), the excess isobaric thermal expansions (αpE), the excess molar isentropic compressibility (κs,mE), the viscosity deviations (Δη), and the deviation of molar refraction (ΔRD). These variations of properties were discussed in terms of solute-solvent interactions occurring between the components of the solutions. Eyring theory of vicos flow is used to calculate excess activation functions (ΔG#E), ΔH#E and ΔS#E of DES solutions.

Thermodynamic (volume and viscosity) of amino acids in aqueous hydroxypropyl-β-cyclodextrin solutions at different temperatures

Densities, ρ, and viscosities, η for L-serine, L-threonine, and L-histidine in 0.01mol·kg−1 aqueous solutions of hydroxypropyl-β-cyclodextrin have been measured at T=(293.15, 298.15, 303.15 and 308.15)K using DMA 5000M densimeter and AMVn viscometer. The ρ and η values have been utilized to evaluate values of the apparent molar volume (Vϕ), limiting apparent molar volume (Vϕ0) and the slope (SV), transfer volume (ΔtrVϕ0), limiting apparent molar expansibilities (ϕE0), hydration number (nH), Falkenhagen coefficient (A) and Jones-Dole coefficient (B) of the systems studied. The results are interpreted in terms of solute-solvent interactions based on a co-sphere overlap model and host-guest interactions.

Effect of temperature on the partial molar volumes and viscosities of two macrocyclic aminals in water and deuterium oxide

In this study the apparent molar volumes and the viscosities of solutions of 1.3.5.7-tetraazatricyclo [3.3.1.13.7] decane (HMT) and 1.3.6.8-tetraazatricyclo [4.4.1.13.8] dodecane (TATD) in water and deuterium oxide or heavy water were determined at T=(293.15, 298.15, 300.15 and 305.15K). The effect of temperature on the volumetric and the viscometric properties of the solutes is discussed in terms of solute-solvent interactions. The thermodynamic behavior of the aminal solutions in water is compared with the behavior observed in deuterium oxide and the results are discussed in terms of the effect of these solutes on solvent structure.

Solubility enhancement of simvastatin and atorvastatin by arginine: A solvodynamics study

Arginine (ARG) aided solubility enhancement of statin-based model drugs such as simvastatin (SMV) and atorvastatin (ATV) has been reported. Herein, both SMV and ATV are considered as a solute, whereas ARG the cosolute. The present study deals with experiments to illustrate the solute-solvent interaction, solute-cosolute interaction and the thermodynamic parameters during the solubilisation of the above drug candidates in water in the presence of ARG. The soundspeed values of ARG, Simvastatin-Arginine (SMV-ARG) and Atorvastatin-Arginine (ATV-ARG) systems were determined in water maintaining different concentrations (0.01, 0.02, 0.04, 0.09, 0.18, 0.36 and 0.73moldm−3) of aqueous ARG, with saturated presence of SMV (SMV-ARG) and ATV (ATV-ARG) at 298.15K. Values of refractive index of the above system were recorded at 298.25, 303.15, 308.15, and 313.15K. Refractive index values were used to calculate the molar refractivity and the results discussed accordingly. Values of sound speed were used to evaluate acoustic parameters such as isentropic compressibility (Ks), apparent isentropic molar compressibility (Ksϕ), relative association (Ra), acoustic impedance (Z), internal pressure (πi), and free volume (Vf). It was observed that sound velocity increased with the increase in case of ARG concentration with linear fashion (R2=0.9978). Compressibility values decreased with increase in ARG concentration. Changers in acoustic parameters were discussed in terms of solute-solvent interaction and structural effects of water for all systems.

Solution behavior of metoclopramide in aqueous-alcoholic solutions at 30°C

Densities (ρ) and refractive indices (nD) of solutions of antiemetic drug metoclopramide (4-amino-5-chloro-N-(2-(diethylamino)ethyl)-2-methoxybenzamide hydrochloride hydrate) in methanolwater and ethanol-water mixtures of different compositions were measured at 30°C. Apparent molar volume (φv) of the drug was calculated from density data and partial molar volumes (φv0) were determined from Massons relation. Concentration dependence of nD has been studied to determine refractive indices of solution at infinite dilution (nD0). Results have been interpreted in terms of solute-solvent interactions.

VOLUMETRIC PROPERTIES OF DL-ALANINE IN AQUEOUS SOLUTIONS OF TETRAFLUOROBORATE 1-BUTYL, 3-METHYLIMIDAZOLIUM AT DIFFERENT TEMPERATURES

Densities of DL-alanine in aqueous ionic liquid, 1-butyl, 3-methylimidazolium tetrafluoroborate solutions were measured from 283.15 to 313.15 K. The densities measured were used to calculate apparent molar volumes (VΦ), apparent molar volume limits (VΦ0), transfer molar volume limits (ΔVΦ0) and hydration number (NH). The behavior of (ΔVΦ0) was interpreted in terms of solute-solvent interactions on the basis of the cosphere overlap model. The hydration numbers were positive and explained by dehydration and electrostriction.

Effect of Methanol on Viscosity of Aqueous Solutions of Cationic Surfactants at 298.15 to 323.15 K

Viscosity measurements have been made to the solutions of dodecyltrimethylammonium bromide (DTAB) and cetyltrimethylammonium bromide (CTAB) in 0.10, 0.20, 0.30, and 0.40 volume fractions of methanol in methanol-water mixed solvent media at 298.15, 308.15, 318.15, and 323.25 K. Critical micelle concentration (CMC) values have been determined. From relative viscosity for surfactant solutions, related viscosityBcoefficients are calculated and the values are interpreted in terms of solute-solvent interactions.

Photoisomerization and structural dynamics of two nitrosylruthenium complexes: a joint study by NMR and nonlinear IR spectroscopies.

In this work, the photoisomerization and structural dynamics of two isomeric nitrosylruthenium(ii) complexes [Ru(OAc)(2cqn)2NO] (H2cqn = 2-chloro-8-quinolinol) in CDCl3 and DMSO are examined using NMR and IR spectroscopic methods. The two N atoms in the 2cqn ligand are in trans position in the synthesized cis-1 isomer, while they are in cis position in the cis-2 isomer. Kinetics monitored by NMR spectroscopy shows that the rate constant of photoisomerization from cis-2 to cis-1 isomer depends on the wavelength of irradiation and solvent polarity; it proceeds faster on irradiating near the absorption peak in the UV-Vis region, and also in more polar solvents (DMSO). Density functional theory computation indicates that the peculiarity of [Ru(ii)-NO(+)] group affects the structure and reactivity of the nitrosylruthenium complexes. Using the nitrosyl stretching (νNO) to be vibrational probe, the structural dynamics and structural distributions of the cis-1 and cis-2 isomers are examined by steady-state linear infrared and ultrafast two-dimensional infrared (2D IR) spectroscopies. The structural and photochemical aspects of the observed spectroscopic parameters are discussed in terms of solute-solvent interactions for the two nitrosylruthenium complexes.

Identification of molecular-interactions using ultrasonic studies on solutions of sodium salt of 2-hydroxy benzoic acid

The molecular interaction behavior of analgesic and antipyretic drug Sodium 2-hydroxy benzoic acid with particular emphasize on its intermolecular interaction was studied using ultrasonic technique at 4 MHz frequency at three different concentrations 0.1M, 0.01M, 0.001M. Ultrasonic velocity, viscosity, and density were measured at three different temperatures 298K, 303K and 308K. Different interaction parameters have been calculated using the experimental values of density, viscosity and ultrasonic velocity of aqueous solution of sodium 2-hydroxy benzoic acid. Results are interpreted in terms of solute-solvent interactions.