Volumetric and acoustic studies of glycine in aqueous solutions of sulphathiazole drug at T=(288.15 to 308.15) K

1800-1808The densities (ρ) and speeds of sound (u) for glycine in aqueous solutions of (0.01, 0.02, 0.03, and 0.04) mol·kg-1 sulphathiazole drug have been measured at T = (288.15, 293.15, 298.15, 303.15 and 308.15) K, using vibrating tube digital densimeter and sound analyser Anton–Paar Model DSA - 5000. The apparent molar properties like apparent molar volume (Vφ), apparent molar adiabatic compressibility (Kφ, s0) and the apparent molar volume (Vφ0) and adiabatic compressibility at infinite dilution (Kφ,s 0) of glycine have been determined in water as well as in ternary mixtures containing sulphathiazole drug at different concentrations and at different temperatures from experimental data of densities and speeds of sound under atmospheric pressure. These data were also used to calculate the transfer parameters. Transfer parameters have been explained from the point of view of concentration dependence of solute-solute and solute-solvent interactions. The limiting apparent molar expansibility (E) values for glycine in aqueous solutions of drug have been calculated. The calculated values of thermal expansion coefficient (α2) have small and positive values. These results are explained on the basis of drug-amino acid - water interactions and hydrophobic –hydrophilic interactions

Interaction studies of diglycine with aqueous solutions of sulphathiazole drug at different temperatures

1164-1171The interactions of diglycine with sulphathiazole drug as a function of temperatures have been studied using volumetric and acoustic parameters. Densities and speeds of sound of diglycine in (0.001, 0.002, 0.005 and 0.010) mol·kg-1 aqueous solutions of sulphathiazole drug have been measured at five different temperatures of (288.15, 293.15, 298.15, 303.15 and 308.15) K under 0.1 MPa pressure. From density data, the apparent molar volume, the partial molar volume and the standard partial molar volume of transfer for glycine from water to aqueous sulphathiazole solutions have been calculated. Partial molar isentropic compression and partial molar isentropic compression of transfer have been calculated from the speed of sound data. Transfer parameters by using cosphere overlap model have been explained on the basis of ionic-hydrophilic, hydrophilic-hydrophilic, hydrophilic-hydrophobic and hydrophobic-hydrophobic group interactions. To draw the conclusion from the volumetric and acoustic data, limiting apparent molar expansion as well as the hydration numbers have been studied. The calculated values of thermal expansion coefficient have small and positive values. All of these derived or calculated parameters are explained to understand the solvation behaviour and various types of interactions born in the ternary solutions of (dipeptide + drug + water) due to change in structure. We have also attempted to examine the temperature and concentration dependence of such interactions

Different approaches to calculate ideal expansibility, internal pressure and speed of sound of binary liquid mixtures, and their excess counterparts

755-759The excess properties are often discussed in terms of molecular interaction in binary liquid mixtures. Different approaches are reported for estimating the ideal contribution to excess speeds of sound, internal pressures and expansibilities. In this overview, these are examined and some suitable errors are identified

Evaluation of excess isentropic compressibilities and viscosities of <em>n</em>-butoxyethanols with water at 298.15 K

109-113A number of approximations have been proposed to obtain the ideal contribution to excess isentropic compressibilities and viscosities

Excess molar volumes and viscosities of the binary mixtures of ethylene glycol monoisopropyl ether with water at 298.15, 308.15 and 318.15K

421-424Excess molar volumes (VEm) and viscosities (&eta;) have been measured for ethylene glycol monoisopropyl ether + water from 298.15 to 318.15 K at 10 K intervals. The excess volumes are negative while viscosities are positive over the entire composition range for the system studied. and temperature has no appreciable influence on excess volumes. The observed negative VEm values are compared with the available published results at 298.15 K. Densities (&rho;) and deviations in viscosity (&Delta;&eta;)) of the mixtures have been calculated from the results. The deviations in viscosity values are positive over the entire range of mole fractions and temperatures. The results of excess molar volume and deviations in viscosity are fitted to the Redlich-Kister relation to estimate the adjustable parameters and standard deviations

Viscosities for binary liquid mixtures of <i>n</i>-alkoxyethanols with water at 298.15K

137-140Viscosities at 298.15 K for three alkoxyethanol+water mixtures have been measured over the whole mole fraction range by using an Ubbelohde viscometer . The alkoxyethanol was 2-(2-methoxyethoxy)ethanol or 2-(2- ethoxyethoxy)ethanol or 2-(2-butoxyethoxy)ethanol. From the experimental data, excess logarithmic viscosities (In ηE) and excess energies of activation for viscous flow (G*E) have been calculated. The excess functions are positive over the entire range of composition for all the systems studied. Also the values of parameter d12 have been calculated from the relation ln ηm = x1ln η1 + x2In η2 + x1x2d12, where η1 and η12 refer to the dynamic viscosities of the two pure liquids 1 and 2 whose mole fractions in the mixture are x1 and x2 respectively. The results for In ηE, G*E and d12 are discussed in terms of interactions of water with an ampbipbilic molecule

Viscosities for binary liquid mixtures of some cellosolves with water at 298.15 K

1120-1123Viscosities (η) of three binary mixtures (cello-solve + water) have been measured as a function of mole fraction at 298.15 K using an Ubbelohde viscometer. The cellosolves were 2-[2-(2-methoxyethoxy)ethoxy] ethanol, 2-[2-(2-ethoxyethoxy )ethoxy]ethanol, and 2-[2-(2-butoxyethoxy)ethoxy]ethanol. From the experimental results, excess logarithmic viscosities (In ηE) and excess energies of activation for viscous flow (G *E) have been calculated. All the mixtures show positive excess functions over the entire concentration range and which increase as the aliphatic chain of the cellosolve increases. The results are discussed on the basis of molecular interactions between the components of the mixtures

Volumetric and ultrasonic studies of glycine in binary aqueous solutions of mannose, maltose and raffinose at different temperatures

1309-1317Apparent molar volumes and adiabatic compressibilities of glycine ( 0.05-0.30 mol kg-1) in aqueous  mannose, maltose  and raffinose solutions ranging from pure water to 6.0 mass % of saccharides have been determined at 288.15, 298.15 and 308.15 K from precise measurements of density and speed of sound. Partial molar volumes and partial molar adiabatic compressibilities of glycine at infinite dilution are evaluated. These values are used for calculating the number of water molecules hydrated to glycine molecule. Transfer volumes and transfer adiabatic compressibilities at infinite dilution from water to aqueous saccharide solutions have also been calculated. Transfer parameters have been interpreted in terms of solute-cosolute interactions on the basis of cosphere overlap model. Pair and triplet interaction coefficients have also been calculated from transfer parameters