Viscosity B-coefficients Research Articles

Interactions in aqueous solutions of imidazolium chloride ionic liquids [Cnmim][Cl] (n = 0, 1, 2, 4, 6, 8) from volumetric properties, viscosity B-coefficients and molecular dynamics simulations

In this work a systematic study of aqueous diluted solutions (~0.005 < m/mol·kg−1 < ~0.1) of six imidazolium based ionic liquids (IL) [Cnmim][Cl] with different alkyl chain lengths (n = 0, 1, 2, 4, 6, 8) was carried out. Densities and viscosities were measured as a function of IL concentration in the temperature range between 278.15 K and 313.15 K in steps of 5 K. From experimental data, apparent molar volumes, standard partial molar volumes, and viscosity B-coefficients of ILs were derived. The effect of the alkyl chain length on the estimated properties was discussed in terms of ion-ion and ion-solvent interactions. It turned out that the studied cations with longer alkyl side chain (n = 4, 6, 8) can be regarded as structure makers; cations with shortest side chain (n = 0, 1) as structure breakers, whereas [C2mim]+ can be considered as a border line ion. In order to obtain more information about interactions and influence of studied ILs on water structure, computational simulations were performed. For this purpose, DFT calculations using B3LYP-D3 functional and molecular dynamic simulations with OPLS 2005 force field, were applied. Obtained results show that the increase in length of alkyl substituent in imidazolium ring leads to weakening of interactions with water molecules.

A relationship between the effect of uni-univalent electrolytes on the structure of water and on its volatility.

The effect of ions on the structure of water in dilute solutions, whether they are structure-makers or structure-breakers, is manifested also in the volatility of the water. For more than 40 uni-univalent electrolytes, there is a linearly increasing relationship between 2φ(m = 0.4) - φ(m = 0.2), where φ is the osmotic coefficient and m is the molality, and the difference between the viscosity B-coefficients of the cation and anion. Exceptions to this relationship are electrolytes with highly structure-making anions and with hydrophobic cations.

Salting-in/Salting-out Mechanism of Carbon Dioxide in Aqueous Electrolyte Solutions

The solvation of carbon dioxide in sea water plays an important role in the carbon circle and the world climate. The salting-out/salting-in mechanism of CO2 in electrolyte solutions still remains elusive at molecule level. The ability of ion salting-out/salting-in CO2 in electrolyte solution follows Hofmeister Series and the change of water mobility induced by salts can be predicted by the viscosity B-coefficients. In this work, the chemical potential of carbon dioxide and the dynamic properties of water in aqueous NaCl, KF and NaClO4 solutions are calculated and analyzed. According to the viscosity B-coefficients, NaClO4 (0.012) should salt out the carbon dioxide relative to in pure water, but the opposite effect is observed for it. Our simulation results suggest that the salting-in effect of NaClO4 is due to the strongly direct anion-CO2 interaction. The inconsistency between Hofmeister Series and the viscosity B-coefficient suggests that it is not always right to indicate whether a salt belongs to salting-in or salting-out just from these properties of the salt solution in the absence of solute.

Effect of fruit and milk sugars on solute–solvent interactions of diphenhydramine-hydrochloride drug in aqueous solutions in viewpoint of volumetric and transport properties

Abstract The effect of (D−)-fructose (fruit sugar), (D+)-galactose and (D+)-lactose (milk sugar) on the solute–solvent interactions occurred between the diphenhydramine-hydrochloride (DPH-HCl) drug and water was studied. To this end, the density, speed of sound and viscosity data for DPH-HCl drug in water and aqueous solutions of (D−)-fructose, (D+)-galactose and (D+)-lactose should have been measured. Thermodynamic properties such as the apparent molar volume (Vϕ) and apparent molar isentropic compression (Ks,m) were calculated from the density and speed of sound values within sugar molality range of (0.05, 0.1, and 0.15) mol kg−1 at T = (288.15, 293.15, 298.15, 308.15 and 318.15) K. Extrapolation to the infinite dilution of Vϕ and Ks,m values with using Redlich–Meyer equation was applied to find the corresponding limiting apparent molar quantities. Jones–Dole equation was used to obtain the viscosity B-coefficients. Interparticle interactions occurred between the DPH-HCl drug and water were determined by calculating the transfer parameters of limiting apparent molar volume and viscosity B-coefficient from DPH-HCl in water to the DPH-HCl in aqueous (D−)-fructose, (D+)-galactose and (D+)-lactose solutions.

Density, viscosity, refractive index and conductivity of switchable hydrophilicity solvent systems: N,N-Dimethylbenzylamine, water and carbon dioxide

Density, viscosity, refractive index and conductivity of switchable hydrophilicity solvent (SHS) systems (N,N-dimethylbenzylamine (BDMA), water, and carbon dioxide) were measured as a function of molality of BDMAH-bicarbonate salt for the SHS system at temperatures from (283.15–308.15) K. Three empirical equations were successfully applied to correlate the density, viscosity, refractive index, and electrical conductivity of the SHS systems with temperature and BDMAH-bicarbonate salt concentration. From these experimental results, apparent molar volume, limiting partial molar volume, the relative viscosity and viscosity B-coefficients were calculated. The limiting apparent molar volumes (Vϕ0) and experimental slopes (Av) derived from the Redlich-Mayer type equation have been interpreted in terms of solute-solute and solute-solvent interactions. In terms of Jones-Dole equation, the viscosity B-coefficients with large positive value and dB/dT < 0 were obtained and these facts implied that the BDMAH-bicarbonate salt is water-structure-making.

Modulation of hydration characteristics of carbohydrates in aqueous medium of γ-amino butyric acid via volumetric, rheological and time-domain longitudinal NMR relaxation studies

Carbohydrates such as saccharides and their derivatives are engaged in various biological processes such as in transportation and transmission of genetic material, enzymatic processes, and regulation of metabolism. γ-Amino butyric acid (γ-ABA) is a non-protein amino acid and acts as an inhibitory neurotransmitter in the mammalian cerebral cortex. Volumetric, rheological and spectroscopic investigations are helpful to elucidate the molecular interactions occurring between carbohydrates and γ-ABA in aqueous solution. Therefore, the standard state partial molar volumes, V2° and Jones-Dole viscosity B-coefficients of monosaccharides and their derivatives, polyols and disaccharides were determined in molality, mB range (0.05–0.50) mol·kg−1 aqueous solutions of γ-ABA from the precise density and viscosity measurements at temperature range T=(288.15–318.15) K. These data were used to obtain the corresponding volumes of transfer, ΔtrV2° and change in viscosity B-coefficient, ΔB for carbohydrates from water to aqueous solutions of γ-ABA. The taste quality of studied solutes (carbohydrates) has been appraised in the presence of γ-ABA from apparent massic volumes. The volumetric and viscometric interaction coefficients were calculated from the McMillan-Mayer theory of solutions. The expansion coefficients (∂V2°/∂T)P, second-order derivatives (∂2V2°/∂T2)P and dB/dT coefficients were also determined to study the influence of temperature. These quantities have been explained in terms of various interactions occurring in the ternary system on the basis of co-sphere overlap model suggested by Gurney (1953). Proton (1H) NMR relaxation rates (R1) were also obtained for carbohydrates in different γ-ABA solutions made in 9:1 (w/w) (H2O+D2O) solvent, at T=300K. The results have been compared with our previously reported (Banipal et al., 2015, 2016) studies carried out in L-glycine. The stereochemical effects of studied solutes on hydration controlled by their domineering conformations have also been discussed.

Interaction of D-panthenol with water molecules – Experimental and computational study

Abstract Physicochemical properties and nature of the interactions in {D-panthenol + H2O} mixtures have been investigated measuring density and viscosity over the whole composition range in the temperature range from T = (293.15 to 313.15) K at atmospheric pressure (p = 1·105 Pa). From the theoretical aspects molecular dynamics (MD) simulations and radial distribution functions (RDFs) have been applied in order to understand the nature of interactions and water structuring in the studied system. The effect of D-panthenol molecules on the structural organization of water were studied through excess molar volumes, apparent molar volumes of D-panthenol, partial molar volumes of D-panthenol and water, viscosity B-coefficients and hydration number. It was found that hydroxyl groups of D-panthenol are responsible for forming cavities between D-panthenol molecules in which water molecules can be incorporated.

Volumetric, Viscometric, and1H NMR Studies on Caffeine, Theophylline, and Theobromine in Aqueous Solutions of MgCl2at TemperaturesT= (288.15 to 318.15) K and at Pressurep= 101.3 kPa

Apparent molar volumes (V2,ϕ) and viscosity B-coefficients for xanthine drugs (caffeine, theophylline, and theobromine) in aqueous (0.09999–0.99989) mol·kg–1 MgCl2 solutions have been determined from measured densities ρ and viscosities η, respectively at T = (288.15 to 318.15) K and at pressure p = 101.3 kPa. These studies indicate the decrease in solubilization of xanthine drugs with increasing ionic strengths of MgCl2 solutions. The results have also been interpreted in terms of structure making/breaking ability of solutes. Spectroscopic studies also support that hydrophilic–ionic interactions are greater at lower concentrations of MgCl2, which descend and finally become weaker at higher concentrations of MgCl2. This type of behavior may also be understood in terms of a large dehydration effect.

Effect of Some Vitamins of Group B (B1, B6, B12) on Micellar and Viscosity Properties of Anionic, Cationic and Nonionic Surfactants in Aqueous Solutions

Abstract The influence of vitamins B1 (thiamine hydrochloride), B6 (pyridoxine) and B12 (cyanocobalamine) on the micellization, surface activity and viscometric behavior of anionic surfactant sodium dodecylsulfate, cationic surfactant cetylpyridinium bromide and nonionic surfactant hexadecylpoly[oxyethylene(20)] alcohol at different temperatures was studied. The critical micelle concentration, the micellization thermodynamics, the maximum adsorption density, the standard free energy of adsorption and the other micellar parameters of surfactants in the presence of vitamins B1, B6 and B12 were obtained. On the basis of dependence of the relative viscosities on concentration, the viscosity B-coefficients of the Jones-Dole semiempirical equation were calculated for both premicellar and postmicellar regions. The results of our study allowed the conclusion that vitamins B1, B6 and B12 are solubilized in micelles.

Volumetric Properties, Viscosity, and Refractive Indices of Different Naringenin Solutions at Several Temperatures

Thermophysical properties including densities and viscosities of naringenin in aqueous solutions of ethanol/1-propanol with alcohol concentrations of (24.00 to 40.00) mol·kg–1 have been measured as a function of concentration of naringenin at temperatures from (293.15 to 323.15) K and atmospheric pressure. Also, refractive indices for studied systems have been determined at 298.15 K. The measured data were used to calculate the apparent molar volume (Vϕ), standard partial molar volume (Vϕ0), partial molar volume (V), viscosity B-coefficients, and molar refractions (Rm). The viscosity and refractive index data have been analyzed by Jones–Dole and Lorentz–Lorenz equations, respectively. The trends of variation of experimental and calculated parameters have been discussed according to the interactions between solvents and solute. The obtained results imply that naringenin acts as a structure maker in the studied system.

Volumetric, acoustic and viscometric studies of l-histidine in aqueous solutions of non-steroid anti-inflammatory drug ketorolac tromethamine at different temperatures

In this investigation density, speed of sound and viscosity of l-histidine (0.015–0.135) molkg−1 in aqueous ketorolac tromethamine solutions (0.1–0.7) molkg−1 at various temperatures (293.15, 298.15, 303.15, 308.15 and 308.15) K and at atmospheric pressure were studied. These data were further used to calculate apparent molar volume, VΦ, limiting apparent molar volume, V°Φ, limiting apparent molar volume of transfer, V°Φ,tr, apparent molar isentropic compression, KΦ,S, limiting molar isentropic compression, K°Φ,S, limiting apparent molar isentropic compression of transfer, K°Φ,S,tr, hydration number, nH, Jones-Dole coefficient-B, B, viscosity B-coefficients of transfer, Btr and the activation parameters, ∆μ°#1 and ∆μ°#2. The results obtained from all these thermodynamic parameters were discussed in terms of solute-solute interactions and solute-solvent interactions on the basis of co-sphere overlap model and the transition state theory.

Structure making behaviour of L-histidine in aqueous solutions of ampicillin sodium at different temperatures: Using physicochemical methods

Experimentally determined values of density (ρ), speed of sound (u) and viscosity (η) have been used to investigate solute-solvent interactions of L-histidine in aqueous ampicillin sodium (an antibacterial drug) solutions at different concentrations (0.035, 0.055, 0.075 and 0.095)molkg−1, over a wide range of temperatures (293.15, 298.15, 303.15, 308.15 and 313.15)K and at atmospheric pressure. The experimentally determined density (ρ) data has been used to obtain various parameters, for instance: apparent molar volume (VΦ), limiting apparent molar volume (VoΦ), limiting apparent molar volume of transfer (VoΦ,tr), limiting molar expansivity (EoΦ) and hydration number (nH). The speed of sound (u) data helps to enumerate apparent molar isentropic compression (KΦ,S), limiting molar isentropic compression (KoΦ,S), limiting apparent molar isentropic compression of transfer (KoΦ,S,tr) and hydration number (nH) i.e., the number of water molecules hydrated to the amino acid. Relative viscosity (ηr), Jones-Dole coefficient-B (B) and viscosity B-coefficients of transfer (Btr) were calculated from viscosity (η) data. The results obtained from this data, showed the existence of physico-chemical interactions, (i.e., hydrophilic-ionic and hydrophilic-hydrophilic) in ampicillin sodium L-histidine solutions. The structure making behaviour of L-histidine in aqueous ampicillin sodium solution was studied in terms of Hepler’s constant ∂2VΦo∂T2P, coefficient of thermal expansion (α) and temperature derivative of B-coefficient (dB/dT).

Effect of temperature on the partial molar volumes, partial molar compressibility and viscosity B-coefficients of DL-4-aminobutyric acid in water and in aqueous sodium chloride solutions

Density, sound velocity and viscosity of DL-4-aminobutyric acid (GABA) in water and in aqueous sodium chloride solutions have been measured at (293.15, 298.15, 303.15, 308.15 and 313.15)K. The apparent molar volumes and the apparent molar compressibilities were calculated at each temperature from the experimental density and sound velocity data. Limiting values at infinite dilution of the partial molar volumes and the partial molar compressibilities of GABA in water and in aqueous sodium chloride solutions were determined through extrapolation at each temperature. The relative viscosity data were adjusted by a least-squares method to a second order equation as proposed by Tsangaris-Martin to obtain the viscosity B coefficients. The influence of temperature on the behaviour of viscosity and the volumetric properties is discussed in terms of molecular interactions.The results confirm that hydrophilic hydration is predominant for GABA in aqueous solution. The addition of NaCl leads to an increase of the partial molar properties at infinite dilution and the viscosity B-coefficients, suggesting that the sodium and the chloride ions interact directly with the zwitterion, reducing the electrostriction of water molecules.

Density, Speed of Sound, and Viscosity of Aqueous Solutions Containing 1-Alkyl-4-methylpyridinium Bromide, Lactic Acid, and Polyethylene Glycol

The effect of some 1-alkyl-4-methylpyridinium based ionic liquids on the thermodynamic and transport properties of l(+)-lactic acid in aqueous polyethylene glycol solutions have been studied. Density, speed of sound, and viscosity of l(+)-lactic acid in the aqueous solutions of polyethylene glycol, (polyethylene glycol + 1-hexyl-4-methylpyridinium bromide) and (polyethylene glycol + 1-octyl-4-methylpyridinium bromide) were measured at T = (288.15, 298.15, 308.15, and 318.15) K. Apparent molar volume, transfer apparent molar volume, apparent molar isentropic compressibility and viscosity B-coefficient of l(+)-lactic acid were calculated using experimental data and were discussed in terms of solute–solute and solute–solvent interactions. The results indicate that solute–solvent interactions were decreased by increasing the concentration of ionic liquid, length of alkyl group of ionic liquid, and temperature.

Effect of glucose/lactose on the solution thermodynamics of thiamine hydrochloride in aqueous solutions at different temperatures

Apparent molar volume, Vϕ, apparent molar isentropic compression, Kϕ,s and viscosity B-coefficients have been evaluated for one of the vitamins, thiamine hydrochloride (thiamine-HCl), in aqueous solutions of two carbohydrates, glucose and lactose, at temperatures (293.15–313.15) K from density, speed of sound and viscosity data. Accordingly, limiting apparent molar volume, V0ϕ, was obtained from Redlich-Meyer equation whereas limiting apparent molar isentropic compression, K0ϕ,s, was calculated on the basis of Debye-Huckel theory. The transfer parameters (ΔtrV 0ϕ, ΔtrK 0ϕ,s and ΔtrB) at infinite dilution, limiting apparent molar expansivity, E0ϕ, Hepler's constant, (∂2V0ϕ/∂T2)P, thermal expansion coefficient, α, pair and triplet interaction coefficients and solvation number, Sn, have also been estimated. The viscosity B-coefficients and activation parameters have been obtained from Jones-Dole equation and transition state theory. The results have been discussed in terms of competing patterns of interactions prevailing in the solute and solvent.

Densities and Viscosities of Aqueous Amino Acid Ionic Liquids [Cnmim][Ala](n = 3, 4, 5)

Amino acid ionic liquids [Cnmim][Ala] (n = 3, 4, 5) (1-alkyl-3-methylimidazolium alanine salt) were prepared by the neutralization method. The density and viscosity for aqueous solutions of the ionic liquids (ILs) with various molalities were measured at T = (288.15 to 328.15) K with an interval of 5 K. In terms of the Jones–Dole equation, the viscosity B-coefficients with large positive values and dB/dT < 0 were obtained, and these facts implied that the ionic liquids are water-structure-making. According to Feakins, the contribution of the solute per mole to the free energy of activation for viscous flow of the solution, Δμ2⧧0, or called as the standard molar activation free energy, was obtained at different temperatures. Under the constant molality of solution, ΔH2⧧0 (the activation enthalpy of the activation for viscous flow of aqueous [Cnmim][Ala] (n = 3, 4, 5)) is a temperature-independent constant. This implies that the activation process of the solute for viscous flow of aqueous [Cnmim][Ala] (n = ...

Ionic Viscosity B-Coefficients of (CH3)4 N+, (C2H5 ) 4N+, (C3H7 ) 4N+, (C4H9)4N+, Na+ , I- and Bph4- in Aqueous Methanol at 298.15 K

Ionic Viscosity B-Coefficients of (CH3)4 N+, (C2H5 ) 4N+, (C3H7 ) 4N+, (C4H9)4N+, Na+ , I- and Bph4- in Aqueous Methanol at 298.15 K

Volumetric, viscometric and 1H NMR spectroscopic studies in (polyhydroxy solute + CTAB + H2O) ternary solutions

To investigate the molecular interactions of polyhydroxy solutes with cetyltrimethylammonium bromide (CTAB) surfactant, we have measured the densities and viscosities of (+)-d-xylose, xylitol, (−)-l-sorbose, d-sorbitol, (+)-d-glucose, and (+)-d-maltose in (4.0, 8.0, and 12.0)·10−4mol·kg−1 CTAB(aq) solutions at (298.15, 308.15 and 318.15) K. The density data have been utilized to evaluate apparent molar volumes (V2,ϕ), partial molar volumes (V2°) and their transfer (ΔtV2°) values at infinite-dilution. The viscosity data were analyzed using the Jones-Dole equation and further used to calculate the viscosity B-coefficients and transfer B-coefficients, ΔtB. The structure-making/-breaking behavior of the polyhydroxy solutes were analyzed using the signs and magnitude of (∂2V2°/∂T2)P and dB/dT coefficients. It has been observed that the positive ΔtV2° and ΔtB values increase with increasing CTAB concentration. 1H NMR spectroscopic study of polyhydroxy solutes was also carried out in mB=(4.0, 8.0, and 12.0)·10−4mol·kg−1 CTAB solutions which were made in 9:1 (w/w) H2O+D2O solvent. NMR results showed higher downfield shift in ternary (polyhydroxy solute+CTAB+9:1 (w/w) H2O+D2O) solutions as compared to pure CTAB solution, hence suggested the predominance of hydrophilic-ionic interactions over hydrophobic-ionic interactions.

Volumetric, Compressibility, Taste Behavior and Viscometric Studies of Methionine with Some Saccharides in Aqueous Medium at Different Temperatures

The density, speed of sound and viscosity of methionine (0.025–0.200 mol·kg−1) in water and some aqueous saccharides (0.1 mol·dm−3 glucose, 0.1 mol·dm−3 sucrose and 0.1 mol·dm−3 lactose) have been measured at temperatures of (293.15, 298.15, 303.15, 308.15 and 313.15) K. Using the experimental values of density and speed of sound, apparent molar volume, limiting apparent molar volume, transfer volume, as well as apparent molar isentropic compressibility, limiting apparent molar isentropic compressibility, transfer compressibility, partial molar expansibility, coefficient of thermal expansion, hydration number and taste behavior have been obtained. Jones–Dole coefficient, viscosity B-coefficients of transfer and variation of B with temperature have also been obtained from viscosity data. The Gibbs energy of activation of viscous flow per mole of solvent as well as per mole of solute, along with other activation parameters, were evaluated employing Feakin’s transition state theory.

Volumetric and viscometric properties of amino acids in aqueous maltitol solutions at T = (293.15–323.15) K

The densities and viscosities of the ternary mixtures of glycine, l-alanine, l-valine, l-threonine and l-arginine in aqueous maltitol solutions were measured at T=(293.15–323.15)K under the atmospheric pressure. The apparent molar volume (Vφ), the limiting partial molar volume (Vφ0) and the limiting partial molar volume of transfer (ΔtrVφ0) were obtained in terms of the measured density, then the viscosity B-coefficient was further calculated by the least-square method. Meanwhile, the partial molar isobaric expansion (E20), the isobaric thermal expansion coefficient (α2), the solvation number (nS), the free energies of activation per mole of solvent (Δμ10≠) and per mole of solute (Δμ20≠) were also calculated. The volumetric and viscometric properties were analyzed and discussed according to the interactions between amino acids and maltitol molecules based on the co-sphere overlap model and the transition state theory.