Mrityunjaya I. Aralaguppi

Excess molar volume, excess isentropic compressibility and excess molar refraction of binary mixtures of methyl acetoacetate with benzene, toluene, m-xylene, mesitylene and anisole

Aralaguppi M.I., Aminabhavi T.M. and Balundgi R.H., 1992. Excess molar volume, excess isentropic compressibility and excess molar refraction of binary mixtures of methyl acetoacetate with benzene, toluene, m-xylene, mesitylene and anisole. Fluid Phase Equilibria, 71: 99-112. Excess molar volume, excess isentropic compressibility and excess molar refraction of binary mixtures of methyl acetoacetate (MAA) with benzene, toluene, m-xylene, mesitylene and anisole have been determined. The results are fitted to a third order polynomial relation to estimate the coefficients and standard errors. The excess molar volumes of all the binary mixtures over the temperature range 298.15–308.15 K are positive, suggesting the presence of weak dispersion-type molecular interactions. The isentropic compressibilities are negative for mixtures of MAA with benzene and toluene; however, for mixtures of MAA with mesitylene, anisole and m-xylene, both positive and negative values are obtained. Of all the mixing rules used to predict excess molar refraction, the Eykman relation is recommended for analysis of refractive index data.

Preparation of cross-linked sodium alginate microparticles using glutaraldehyde in methanol.

Polymeric sodium alginate microparticles were prepared by precipitating sodium alginate in methanol, followed by cross-linking with glutaraldehyde. The extent of cross-linking was controlled by the time of exposure to glutaraldehyde. The topology of microparticles was characterized by scanning electron microscopy (SEM), which indicated smooth surfaces. The equilibrium swelling experiments were carried out in water to observe the effect of cross-linking and drug loading for better utility of microparticles. It was found that swelling decreased, but drug loading increased, with an increase in cross-linking of the matrix.

A study on molecular transport of organic esters and aromatics into viton fluoropolymers

Molecular transport of organic liquids into Viton fluoropolymers has been investigated by a sorption-desorption gravimetric method. Diffusion coefficients have been calculated from Ficks equation. The sorption-desorption results have been used to calculate the concentration profiles by solving Ficks diffusion equation under suitable boundary conditions. A numerical method based on the finite difference technique was also used to calculate the concentration profiles of liquids as a function of sorption time and thickness of the Viton fluoropolymers. The dependence of sorption, desorption, diffusion, and permeation properties of the liquids on temperature showed a significant effect. The Arrhenius activation parameters have been estimated for diffusion, permeation, and sorption processes. The experimental and calculated results are discussed to study the type and nature of interactions between Viton fluoropolymers and the solvent molecules.

Polarizability and molecular radius of bromoform and hydrocarbon liquids

Abstract Aminabhavi, T.M., Aralaguppi, M.I., Harogoppad, S.B. and Balundgi, R.H., 1992. Polarizability and molecular radius of bromoform and hydrocarbon liquids. Fluid Phase Equilibria, 72: 211-225. Densities and refractive indices of bromoform, n -heptane, n -octane, 2,2,4-trimethylpen- tane, n -nonane, n -decane, n -tetradecane, n -hexadecane and 1,2,3,4-tetrahydronaphthalene have been measured over the temperature interval of 298.15-323.15 K. Polarizabilities and molecular radii were calculated on the basis of Bottchers theory of electric polarization and compared with the molecular radii evaluated from the molar volumes of the liquids and from free volume considerations. Bottchers theory is found to be satisfactory in estimating the molecular radii and polarizability of long-chain molecules. Lorenz-Lorentz and Eykman relations have been used to calculate the thermal expansion coefficients and the polarizabil- ities of liquids.