Meena Sharma

Acoustical and thermodynamical parameters of aluminium oxide nanoparticles dispersed in aqueous ethylene glycol

ABSTRACT In the present work aluminium oxide (Al2O3) nanoparticles were synthesised by the precipitation method using AlCl3 as a starting material. The synthesised nanoparticles were characterised by X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), and energy dispersive X-ray spectroscopy (EDX). These nanoparticles have been dispersed in base fluid, an aqueous solution of ethylene glycol (EG). Density (ρ), ultrasonic velocity (u), and viscosity (η) for these nanofluids have been measured at different concentrations as a function of temperature (T = 303.15 K, 308.15 K, and 313.15 K). Using their values various acoustical and thermodynamical parameters have been computed.

Fe–Al/clay as an efficient heterogeneous catalyst for solvent-free synthesis of 3, 4-dihydropyrimidones

AbstractA practical, efficient, environmentally benign condensation of an aldehyde, ethylacetoacetate and urea/thiourea for the synthesis of 3, 4-dihydropyrimidinones, employing Fe–Al/clay composite catalyst is described. The process has been carried out under solvent-free conditions in the presence of very small amount of catalyst. The catalyst used for this process is easy to prepare, easy to handle, cost effective, easy to separate and recyclable at least up to 5 cycles with good to excellent yield. Graphical AbstractA heterogeneous catalyst (Fe–Al/clay composite) has been prepared by a simple procedure from easily available materials and applied for the synthesis of 3, 4-dihydropyrimidinones, from aldehyde, ethylacetoacetate and urea/ thiourea under solvent-free conditions.

Structure-making behaviour of L-arginine in aqueous solution of drug ketorolac tromethamine: volumetric, compressibility and viscometric studies

ABSTRACT In this work, density ρ, speed of sound u and viscosity η, were measured for L-arginine in aqueous ketorolac tromethamine solutions at various temperatures (293.15, 298.15, 303.15, 308.15 and 313.15 K) and at atmospheric pressure. Apparent molar volume VΦ, limiting apparent molar volume V°Φ, limiting apparent molar volume of transfer V°Φ,tr, limiting molar expansivity E°Φ, Hepler’s constant and hydration number nH were obtained using density data. Apparent molar isentropic compression KΦ,S, limiting apparent molar isentropic compression K°Φ,S, limiting apparent molar isentropic compression of transfer K°Φ,S,tr and hydration number nH were obtained using speed of sound data. Jones–Dole coefficient-B B, viscosity B-coefficients of transfer Btr, variation of B with temperature (), free energy of activation of viscous flow per mole of solvent Δμ°#2 and per mole of solute Δμ°#1 were obtained from viscosity data. The obtained results are discussed in terms of solute–solvent interactions in these systems.

Solvation behaviour of L-leucine in aqueous ionic liquid at different temperatures: Volumetric approach

For the investigation of interactions of L-leucine in aqueous solutions of an ionic liquid (1-butyl-3-methylimidazolium tetra fluoroborate [Bmim][BF4]) at atmospheric pressure over a temperature range of (293.15K to 313.16K), we use the volumetric approach. By using the density data we have calculated the apparent molar volume, VΦ, limiting apparent molar volume, V0Φ, the slope, Sv, partial molar volume of transfer, V0Φ,tr. The values of these acoustical parameters have been used for the interpretation of different interactions like hydrophilic-hydrophilic, hydrophilic-hydrophobic, ion hydrophilic, solute-solvent and solute-solute interactions in the amino acid and ionic liquid solutions.For the investigation of interactions of L-leucine in aqueous solutions of an ionic liquid (1-butyl-3-methylimidazolium tetra fluoroborate [Bmim][BF4]) at atmospheric pressure over a temperature range of (293.15K to 313.16K), we use the volumetric approach. By using the density data we have calculated the apparent molar volume, VΦ, limiting apparent molar volume, V0Φ, the slope, Sv, partial molar volume of transfer, V0Φ,tr. The values of these acoustical parameters have been used for the interpretation of different interactions like hydrophilic-hydrophilic, hydrophilic-hydrophobic, ion hydrophilic, solute-solvent and solute-solute interactions in the amino acid and ionic liquid solutions.