Apparent Specific Volume Research Articles

Volumetric Behavior of Sodium Saccharin in Water and (0.1, 0.3, and 0.5) m Fructose at (298.15, 303.15, 308.15, and 313.15) K

In order to get the information regarding the sweetener-water and sweetener-sweetener interactions, densities of sodium saccharin in water and (0.1, 0.3, and 0.5) m fructose have been measured at (298.15, 303.15, 308.15, and 313.15) K by the use of bicapillary pycnometer. From density values, partial molar volumes, expansion coefficient, Hepler’s constant, apparent specific volumes, partial molar volumes of transfer, doublet and triplet interaction coefficients have been calculated. From density study, it has been concluded that strong water-sodium saccharin interactions exist. Sodium saccharin is water structure maker. Strong interactions exist between sodium saccharin and fructose. In presence of fructose, the interactions exist between hydrophilic group (–OH, C=O, and –O–) of fructose and sodium ion of sodium saccharin in aqueous solutions of sodium saccharin. All investigated solutions exhibit sweet taste. DOI: http://dx.doi.org/10.17807/orbital.v9i1.921

Hydration properties of glycylglycine in aqueous ionic liquid solutions at different temperatures: Volumetric and acoustic approach

The apparent molar volume and isentropic compression of glycylglycine in aqueous 1-methylimidazolium chloride, [mim][Cl], 1-ethyl-3-methylimidazolium chloride [C2mim][Cl], and 1-methyl-3-octylimidazolium chloride [C8mim][Cl] solutions have been calculated from the measured experimental data on density and speed of sound at temperature, T=288.15, 298.15 and 308.15K. The apparent molar volumes at infinite dilution, Vϕ0 and the apparent isentropic molar compression at infinite dilution Kϕ,S0, were also calculated. Furthermore, apparent specific volumes, apparent molar expansivity, Eϕ0, Hepler's constant values, ∂Eϕ0∂TP and hydration numbers, nH, have been evaluated to support the conclusions obtained from the volumetric and acoustic studies. The Hepler's constant values were found negative which indicating the peptide under study is predominantly a structure breaker due to hydrophobic hydration of small peptide in aqueous ionic liquid.

Solution thermodynamics and taste behaviour of nicotinic acid in aqueous sodium gluconate solutions: A volumetric and rheological perspective

Changes in hydration layer of a solute in presence of a cosolute are crucial in understanding structural organisation of water molecules around the solute. Thermodynamic and transport properties can provide valuable information in this regard. The effect of sodium gluconate (NaG) on the hydration behaviour and taste quality of nicotinic acid (NA) were studied through apparent molar volumes (φV), partial molar volumes (φV0) at infinite dilution, apparent specific volumes (φASV), viscosity B-coefficients and solvation numbers (Sn) in (0.00, 0.02, 0.04, and 0.06) mol ⋅ kg− 1 aqueous sodium gluconate solutions at T = (298.15–318.15) K under atmospheric pressure. The results have been explored in terms of solute-solvent and solute-cosolute interactions occurring in the studied solutions. UV–Visible absorption spectra of the solutions also stand in support of the results obtained.

Volumetric and Acoustic Behavior of Sodium Cyclamate in Aqueous System from 293.15 K to 318.15 K

Density (ρ) and sound velocity (u) measurements were carried for aqueous solutions of sodium cyclamate (SC) from 293.15 to 318.15 K. Apparent molar and specific volumes, isentropic apparent molar compressibility and hydration numbers were computed from the experimental measurements. Apparent molar volumes (Φ V ) of SC show negative deviations from the Debye–Huckel limiting law and the values obtained for Φ V at given temperatures and concentrations were used as a direct measure of the ion–ion and ion–solvent interactions. Interactions causing a sweet taste require a specific volume to stimulate receptor sites from water and possibly also in the biophase. Furthermore, the partial molar expansibility (Φ E ° ), Hepler’s constant (∂2 Φ V ° /∂T 2 ) and thermal expansion coefficient have been estimated. This study will help to elucidate the structural interactions of SC with water and its taste in foods.

The Thermodynamic Properties of Dynol-604/AOT Mixed Reverse Micelles in Isooctane

The volumetric properties of the mixed surfactants bis(2-ethylhexyl) sodium sulfosuccinate and ethoxylated-2,5,8,11-tetramethyl-6-dodecyne-5,8-diol (Dynol-604) at various compositions in isooctane have been studied by density measurements at 303.15 K. The apparent specific volumes and the critical reverse micelle concentrations of the binary mixed surfactants were determined. The results were used to calculate the compositions, excess properties of mixing, activity coefficients and the interaction parameter between the two surfactants in the mixed micelles, based on Rubingh’s formalism.

Solubility and apparent specific volume at saturation of some pharmaceutical salts in methanol + water mixtures at 298.15 K

Equilibrium solubility of sodium naproxen (Na·NAP), procaine hydrochloride (PC·HCl), and lysine clonixinate (Lys·Clon), was determined in methanol+water mixtures at 298.15K. Mole fraction solubility of Na·NAP increases from neat water (x3=1.71×10−2) to reach a maximum in the mixture with w1=0.90 (x3=5.05×10−2); the solubility of PC·HCl increases from neat water (x3=9.68×10−2) to reach a maximum in the mixture with w1=0.20 (x3=0.1032); whereas, the solubility of Lys·Clon increases from neat water (x3=3.54×10−2) to reach a maximum in the mixture with w1=0.60 (x3=6.33×10−2). The generated solubility data are mathematically represented by using the Jouyban-Acree model with very good error level (average of 1.2% for molar solubilities). In addition, the apparent specific volumes at saturation of these drugs were also calculated in all the mixtures under study using the measured densities of the saturated solutions. In this way, the average apparent volumes at saturation in these mixtures could be considered as follows: 0.699cm3g−1 for Na·NAP, 0.821cm3g−1 for PC·HCl, and 0.730cm3g−1 for Lys·Clon.

Solution properties and taste behavior of lactose monohydrate in aqueous ascorbic acid solutions at different temperatures: Volumetric and rheological approach

The densities and viscosities of lactose monohydrate in aqueous ascorbic acid solutions with several molal concentrations m=(0.00–0.08)molkg−1 of ascorbic acid were determined at T=(298.15–318.15)K and pressure p=101kPa. Using experimental data apparent molar volume (ϕV), standard partial molar volume (ϕV0), the slope (SV∗), apparent specific volumes (ϕVsp), standard isobaric partial molar expansibility (ϕE0) and its temperature dependence (∂ϕE0/∂T)P, the viscosity B-coefficient and solvation number (Sn) were determined. Viscosity B-coefficients were further employed to obtain the free energies of activation of viscous flow per mole of the solvents (Δμ10≠) and of the solute (Δμ20≠). Effects of molality, solute structure and temperature and taste behavior were analyzed in terms of solute-solute and solute-solvent interactions; results revealed that the solutions are characterized predominantly by solute-solvent interactions and lactose monohydrate behaves as a long-range structure maker.

Modulation of volumetric properties of d(+)-glucose in aqueous 3-hydroxypropylammonium acetate solutions

Study of hydration behavior of solute is required to understand the role of water in taste mechanisms, and the effect of additive on basic taste quality of solute. In this regard, apparent molar volume, apparent specific volume, apparent molar isentropic compressibility and apparent specific isentropic compressibility of Glu in aqueous solutions of 3-hydroxypropylammonium acetate (3HPAAc) have been determined at 293.15K to 318.15 and at atmospheric pressure from experimentally measured density, ρ and speed of sound, u data. Derived parameters such as infinite dilution partial molar volumes, V2°, partial molar isentropic compressibilities, volume of transfer, expansion coefficients, hydration numbers, and interaction coefficients were also determined to discuss various interactions occurring between solute and cosolute in aqueous solutions. The effect of cationic and anionic moiety of 3HPAAc on the basic taste behavior of Glu has also been studied on the basis of apparent specific volume and apparent specific isentropic compressibility.

Optimization of Physical and Functional Properties of Sorghum-Bambara Groundnut Extrudates

<p>Blends of sorghum and Bambara groundnut flour at 90:10, 80:20 and 70:30 ratios respectively, were extruded at 20%, 22.5% and 25% moisture levels and 120<sup>o</sup>C, 140<sup>o</sup>C and 160<sup>o</sup>C barrel temperatures using a single-screw extruder. Response surface methodology with central composite face-centered (CCF) design was used to model the viscosity, water absorption index (WAI) water solubility index (WSI), sectional expansion index (SEI), bulk density (BD), apparent specific volume (ASV) and mass flow rate of the extrudates. The viscosity, WAI, WSI, SEI, BD, ASV and MFR of extrudates varied from 8.38 to 18.78 Nsm-<sup>2</sup>, 5.30 to 6.21 g/g water, 10.5 to 21%, 2.55 to 5.1, 0.223 to 0.499 g/cm<sup>3</sup>, 4.15 to 6.55 cm<sup>3</sup>, and 1.19 to 2.3 g/s respectively. The R<sup>2</sup> values were 0.83, 0.71, 0.55, 0.61, 0.66, 0.77 and 0.61 respectively with a non-significant lack of fit; except for viscosity. Plots of residuals against fitted values showed that residuals were randomly scattered in all cases, thus validating the empirical models for the responses. The optimum amount of Bambara groundnut flour, feed moisture and extrusion temperature were established for viscosity, WAI, SEI, BD, ASV and MFR of the extrudates. Feed moisture had the most effect on extrudates functional and physical properties followed by extrusion temperature.<strong></strong></p>

Effect of pH and Glucose on the Stability of α-lactalbumin

The objective of this study is to understand the influence of pH and effect of cosolvent (glucose) on the stabilization of bovine α-lactalbumin by using ultrasonic techniques. Values of density, ultrasonic velocity and viscosity were measured for bovine α-lactalbumin (5 mg/ml) dissolved in phosphate buffer (pH 2, 5, 7, 9 and 12) solutions mixed with and without the cosolvent at 30 °C. These measurements were used to calculate few thermo-acoustical parameters such as adiabatic compressibility, intermolecular free length, acoustic impedance, relaxation time, relative association constant, the partial apparent specific volume and the partial apparent specific adiabatic compressibility for the said systems. The obtained results revealed a strong comparison between the effects of acidic and alkaline pH values on protein denaturation, i.e., the acidic pH are instantaneous and are of less magnitude whereas alkaline pH are slower but sharper. Further the present study supports the fact that the presence of glucose stabilizes α-lactalbumin against denaturation due to pH variation, which may be due to the strengthening of non-covalent interactions and the steric exclusion effect.

Solubility and Apparent Specific Volume of Some Pharmaceutical Salts in Propylene Glycol + Water Mixtures at 298.15 K

The equilibrium solubility of three pharmaceutical salts, namely, sodium naproxen (Na.NAP), procaine hydrochloride (PC.HCl), and lysine clonixinate (Lys.Clon), was determined in propylene glycol (PG) + water mixtures at 298.15 K. If the mole fraction concentration scale is considered, the mixtures’ composition-dependence on solubility was different for these drugs. Thus, the solubility of Na.NAP increased nonlinearly from pure water to pure PG. By contrast, the solubility of PC.HCl decreased nonlinearly from pure water to pure PG. In a different way, the solubility of Lys.Clon increased from pure water to the mixture with mass fraction of PG, w1 = 0.80, and later, it decreased to reach a lower value in pure PG. A good correlation of the solubility data was obtained by using the modified NIBS/R-K model. Otherwise, the apparent specific volumes at saturation of these drugs were also calculated in all the mixtures under study.

Density, Speed of Sound, and Viscosity of Some Binary and Ternary Aqueous Polymer Solutions at Different Temperatures

Density, speed of sound and viscosity measurements at (288.15, 293.15, 298.15, 303.15 and 308.15) K were carried out on several binary (water + polymer) and ternary (water + polymer (1) + polymer (2)) systems. Polymers were polyethylene glycol 600 (PEG600), polyethylene glycol 10000 (PEG10000), polypropylene glycol 400 (PPG400), polyethylene glycol dimethyl ether 250 (PEGDME250), and polyvinylpyrrolidone 10000 (PVP10000). The measured density and speed of sound data were used to determine the excess specific volume, isentropic compressibility, and isentropic compressibility increment of the investigated solutions as well as the apparent specific volume, limiting apparent specific volume, limiting apparent specific expansibility, apparent isentropic compressibility, and limiting apparent isentropic compressibility of each polymer in the aqueous solutions of 1 % and 3 % (w/w) other investigated polymers. The intrinsic viscosities for the investigated binary and ternary systems were calculated from the experimental viscosity data. Finally, the ability of polymer (1) in varying the volumetric, compressibility, and viscometric properties of polymer (2) in aqueous solutions was discussed on the basis of the polymer–water and polymer (1)–polymer (2) interactions.

Steric stabilization of modified nanoclays triggered by temperature

Halloysite clay nanotubes were modified through the adsorption of poly(N-isopropylacrylamide)-amine terminated (PNIPA-NH2) onto the external surface by exploiting electrostatic interactions at pH=6. In spite the amount of attached polymer is rather low (1wt%), the properties of the nanotubes are deeply modified. The apparent specific volume and isentropic compressibilities of the hybrid nanomaterial dispersed in water evidenced the transferring of the termosensitive property from the polymer to halloysite. The hydrodynamic radius as well as the ζ-potential of the nanohybrid are consistent with the attachment of a positively charged polymer onto the negative surface of the nanotube. The colloidal stability was strongly enhanced in the temperature domain below the lower critical solution temperature. This methodology endowed to obtain hollow nanotubes with a stimuli-responsive corona.

Плотность упаковки и кажущийся удельный объем модельных и реальных растворов

Плотность упаковки и кажущийся удельный объем модельных и реальных растворов

Solubility and saturation apparent specific volume of some sodium sulfonamides in propylene glycol + water mixtures at 298.15 K

Equilibrium solubility of sodium sulfadiazine (Na.SDZ), sodium sulfamerazine (Na.SMR), and sodium sulfamethazine (Na.SMT), was determined in aqueous binary mixtures of propylene glycol (PG) at 298.15K. If the solubility values expressed in both concentration scales are considered, i.e. mole fraction and molarity, in water-rich mixtures the solubility decrease as: Na.SDZ>Na.SMT>Na.SMR, whereas, in PG-rich mixtures the observed order is: Na.SMT>Na.SDZ>Na.SMR. In all cases the solubility in neat water is higher than those in neat PG. Correlation of the solubility data obtained was made by means of the Jouyban–Acree model for all the sodium sulfonamides. Otherwise, apparent specific volumes (ϕVsp) of sodium sulfonamides at saturation were also calculated in all the mixtures. The average ϕVsp values are as follows: 0.663cm3g−1 for Na.SDZ, 0.723cm3g−1 for Na.SMR, and 0.740cm3g−1 for Na.SMT, with a variation lower than 5.0% in each case.

Modelling of system parameters of extruded sorghum–cowpea breakfast cereal using response surface methodology

Blends of sorghum and cowpea flour (10%, 20% and 30%) were extruded at 20%, 22.5% and 25% moisture and 120°C, 140°C and 160°C barrel temperatures respectively, using a single-screw extruder. A central composite face-centered (CCF) design was used to model the specific power consumption (SPC), torque, mass flow rate (MFR) and apparent specific volume (ASV) of the sorghum–cowpea extrudates. The SPC, torque, MFR and ASV varied from 201.71 to 229.28Kwh−1kg−1, 85 to 97Nm, 1.94 to 2.31gs−1 and 4.01 to 6.36cm3, respectively. The SPC was significantly (p<0.05) influenced by the linear effect of feed composition and the interaction effects of feed moisture and extrusion temperature. The torque was however significantly (p<0.05) influenced by the linear effect of feed moisture and the interaction effects (p<0.01) of feed moisture and extrusion temperature. The ASV was significantly (p≤0.01) influenced by the linear effect of extrusion temperature and the quadratic effect of extrusion temperature as well as the interaction effects of feed composition and feed moisture. The coefficients of determination were 0.78, 0.79, 0.63 and 0.86 for SPC, torque, MFR and ASV, respectively. There was no significant lack of fit for the SPC, torque, and MFR of the extrudates. The correlation coefficients (r2) for the observed and predicted values were 0.88, 0.75, 0.78 and 0.93 for SPC, torque, MFR and ASV, respectively, indicating a good fit for the model. The CCF was found appropriate in predicting the SPC, torque, MFR and ASV of the extrudates.

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

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

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

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

Study of thermodynamic and transport properties of aqueous system containing poly(ethylene glycol) dimethyl ether 2000 and poly(propylene glycol) 400

Mixture of {poly(ethylene glycol) dimethyl ether 2000 (PEGDME2000)+poly(propylene glycol) 400 (PPG400)+water} forms an aqueous two phase system. For this system the binodal curves were measured at two temperatures from which the single phase region was obtained. The density, speed of sound and viscosity measurements were performed in the single phase region for {poly(ethylene glycol) dimethyl ether 2000 (PEGDME2000)+poly(propylene glycol) 400 (PPG400)+water} system and the corresponding binary ((PPG400)+water) solutions at T=(293.15, 298.15, 303.15, 308.15, and 313.15)K. From these measurements, values of the excess molar volume (VmE) and isentropic compressibility deviation (ΔKS) were calculated and correlated to the modified Wilson and polymer NRTL models. The viscosity values of binary and ternary solutions were correlated by the Eyring-modified Wilson and Eyring-NRTL models. From the density data for the binary and ternary solutions at dilute range, the apparent specific volumes at infinite dilution values were also determined. Some information regarding the segment–solvent and segment–segment interactions is obtained from these values.

Volumetric properties of water/AOT/isooctane microemulsions.

The densities of AOT/isooctane micelles and water/AOT/isooctane microemulsions with the molar ratios R of water to AOT being 2, 8, 10, 12, 16, 18, 20, 25, 30, and 40 were measured at 303.15 K. The apparent specific volumes of AOT and the quasi-component water/AOT at various concentrations were calculated and used to estimate the volumetric properties of AOT and water in the droplets and in the continuous oil phase, to discuss the interaction between the droplets, and to determine the critical micelle concentration and the critical microemulsion concentrations. A thermodynamic model was proposed to analysis the stability boundary of the microemulsion droplets, which confirms the maximum value of R being about 65 for the stable AOT/water/isooctane microemulsion droplets.