Divya Shukla

Mixing properties and modelling of methanol with chlorobenzene and bromobenzene at 293, 303, and 313 K

Refractive index, ultrasonic velocity and density for the binary mixtures of methanol with chlorobenzene and bromobenzene at 293, 303, and 313 K have been measured over the entire composition range. The values of refractive index (n), ultrasonic velocity (u), and density (ρ) were used to compute deviation in molar refraction (ΔR m) and deviation in isentropic compressibility (Δκ s). The results of deviation were fitted to the Redlich–Kister polynomial equation to derive the binary coefficients and standard deviation. Both the systems exhibited negative values of ΔR m and Δκ s over the entire composition range. The density, ultrasonic velocity and refractive index were correlated to first order polynomial with respect to mole fraction. Experimental data of physical properties (refractive index, isentropic compressibility and density) were compared with the results obtained by theoretical estimation procedures.

Thermoacoustical study of molecular interactions in binary mixtures of pentane with methanol and tert-butanol

Experimental values of density, ultrasonic velocity and viscosity for the binary mixtures of pentane with methanol and tert-butanol have been measured at 293.15, 298.15 and 303.15 K over the entire composition range. Using these experimental data, specific heat ratio, heat capacity, effective Debye temperature, pseudo-Grüneisen parameter, viscosity deviation, excess internal pressure, excess Gibbs free energy of activation for viscous flow and excess molar enthalpy have been calculated and computed results were fitted to the Redlich-Kister polynomial equation. These parameters were used to study the nature and extent of intermolecular interaction between components molecules present in the binary mixtures. The results suggest that stronger specific interactions are taking place in pentane + methanol mixture than in pentane + tert-butanol mixture. Furthermore, various empirical relations were used to correlate the ultrasonic velocities of these mixtures. An excellent agreement has been found between experimental and theoretical values.

On the Determination of Equilibrium Constant and Thermodynamic Parameters for the Association Process of Hydrogen Bond Complexes Using Relaxation Parameters

Abstract A dielectric study of H-bond complexes of three acetates namely ethyl acetate, butyl acetate, and benzyl acetate with the proton donor (O-Cresol) has been made. The equilibrium constant and the thermodynamic parameters for the association process as well as the dielectric relaxation process have been determined from the dielectric data using an equation, proposed in our earlier paper. The results obtained being in agreement with the literature values thus support the validity of the proposed equation.

Volumetric and optical study of molecular association in binary mixtures of dimethyl sulphoxide with carboxylic acid

Density and refractive index have been measured for the binary mixture of dimethyl sulphoxide (DMSO) with propanoic acid and n-butyric acid at three temperatures, 293, 303 and 313 K, over the entire composition range. Excess parameters such as excess molar volume (V E) and molar refraction deviation (ΔR m) have been calculated from the measured density and refractive index to study the molecular association between the component molecules. The V E and ΔR m values of these mixtures were fitted to the Redlich–Kister polynomial equation. Both excess parameters were plotted against the mole fraction of DMSO over the whole composition range. The values of V E and ΔR m have been found to be negative for both mixtures over the entire composition range, which suggests the presence of strong intermolecular interaction. The experimental refractive data of these mixtures were also used to test the validity of the empirical relations for the refractive index.