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Papers by Dr Urvashi Srivastava

Physics and Chemistry of Liquids, 2018

From the measured work of Ching-Ta and Chein-Hsiun Tu, we have presented the theoretical results ... more From the measured work of Ching-Ta and Chein-Hsiun Tu, we have presented the theoretical results of Surface tension and excess volume for three binary systems: namely 2-Propanol+Benzyl alcohol(1), 2-Propanol+2-Phenylethnol(2) and Benzyl alcohol+2-Phenylethanol(3) at temperatures 298.15, 308.15 and 318.15 K and atmospheric pressure over the concentration range 0.05-0.95. Theoretical results were computed from Flory model, Ramaswamy and Anbananthan (RA) model and model devised by Glinski, and studied the mixing properties and interactions of these liquids. Deviations in the surface tension (Δσ) were evaluated and fitted to the Redlich-Kister polynomial equation to derive the binary coefficients and standard errors. Moreover, McAllister multibody interaction model based on Eyring's theory of absolute reaction rates has also been applied. For liquid mixtures, the free energy of activation is additive, based on the proportions of the different components of the mixture and interactions of like and unlike molecules. The behaviour of the liquids was studied and correlated with the molecular interactions from these liquid state models. Conclusively, these nonassociated and associated models were compared and tested for different systems showing that the McAllister multi-body interaction model yields good results as compared to associated models, while Flory model shows more deviations.

International Journal of Thermophysics, 2016

Density and acoustic velocity were measured for binary liquid mixtures of formamide, N-methylacet... more Density and acoustic velocity were measured for binary liquid mixtures of formamide, N-methylacetamide (NMA), dimethylformamide (DMF), and dimethylacetamide (DMA) with acetonitrile at atmospheric pressure and 293.15 K, 298.15 K, 303.15 K, 308.15 K, or 313.15 K over the concentration range 0.12 to 0.97. Models assuming association and nonassociation of the components of the mixtures were used to predict the behavior of the studied liquids, which would typically show weak interactions. The measured properties were fitted to the Redlich–Kister polynomial to estimate the binary coefficients and standard errors. The data were used to study the molecular interactions in the binary mixtures. Furthermore, the McAllister multibody interaction model was used to correlate the properties of the binary liquid mixtures. Testing of the nonassociation and association models for the different systems showed that, compared with the nonassociation model theoretical results, the association model theoretical results were more consistent with the experimental results.

$Research paper thumbnail of Density, refractive index and molar refractivity of binary liquid mixture at 293.15, 298.15, 303.15, 308.15 and 313.15K$

Arabian Journal of Chemistry, 2016

Densities and refractive indices were measured for the binary liquid mixtures formed by formamide... more Densities and refractive indices were measured for the binary liquid mixtures formed by formamide, N-methylacetamide, di-methylformamide and di-methylacetamide with acetonitrile at T = 293.15, 298.15, 303.15, 308.15 and 313.15 K and atmospheric pressure over the whole concentration range. Lorentz-Lorentz mixing rule, Ramaswamy and Anbananthan model and model devised by Glinski were used to study the refractive index and molar refractivity. These results have been discussed to study the type of mixing behavior between the mixing molecules. The measured data were fitted to the Redlich-Kister polynomial relation to estimate the binary coefficients and standard errors. Furthermore, McAllister multibody interaction model is used to correlate the binary refractive index with the experimental findings. It is observed that molar refractivity, molecular interaction and association constant can be better understood from these models.

Journal of Non-Equilibrium Thermodynamics, 2010

Surface tension and excess volume for trimethyl benzene with tetrahydrofuran, tetra chloromethane... more Surface tension and excess volume for trimethyl benzene with tetrahydrofuran, tetra chloromethane, and diethyl solfoxide were theoretically predicted with the help of the Prigogine-Flory-Patterson (PFP) model over the entire concentration range at 298.15 K, which has immense sense of applicability in organic separation and synthesis as solvent. Further, we found that computed results are in good agreement with the experimental findings. The results so obtained have been explained on the basis of packing effect and dipolar-dipolar interactions. An attempt has also been made to study the excess thermodynamic functions that measure the extent of molecular interactions involved in the liquid mixture.

$Research paper thumbnail of Density, viscosity and refractive index of binary liquid mixtures at 293.15, 298.15, 303.15, 308.15 and 313.15K$

Experimental Thermal and Fluid Science, 2012

Densities, viscosities and refractive indices were measured for the binary liquid mixtures formed... more Densities, viscosities and refractive indices were measured for the binary liquid mixtures formed by formamide, N-methylacetamide, di-methylformamide and di-methylacetamide with acetonitrile at (T = 293.15, 298.15, 303.15, 308.15 and 313.15) K and atmospheric pressure over the whole concentration range. Lorentz-Lorentz (L-L) relation, Prigogine-Flory-Patterson model (PFP), model devised by Glinski and Ramaswamy and Anbananthan (RS) models were used to study the associational behavior of weakly interacting liquids from viscosity and refractive index data. These non-associated and associated models were compared and also tested for different systems. The measured properties were fitted to Redlich-Kister polynomial relation to estimate the binary coefficients and standard errors. Furthermore, McAllister multi body interaction model was used to correlate the binary properties. Conclusively, viscosities and refractive indices of binary liquid mixture can be better understood from these models and interactions and association constant can be well predicted. The associated processes yield fair agreement between theory and experiment as compared to non-associated processes.

Canadian Journal of Physics, 2013

Densities and surface tensions were measured for the binary liquid mixtures formed by formamide, ... more Densities and surface tensions were measured for the binary liquid mixtures formed by formamide, N-methylacetamide, di-methylformamide, and di-methylacetamide with acetonitrile at 293.15, 298.15, 303.15, and 313.15 K and atmospheric pressure over the whole concentration range. The Prigogine–Flory–Patterson model, the Ramaswamy and Anbananthan model, the model devised by Glinski, the Sanchez equation, the Goldsack relation, and the Eberhart model were used to predict the associational behaviour of weakly interacting liquids. The measured properties were fitted to the Redlich–Kister polynomial relation to estimate the binary coefficients and standard errors. Furthermore, the McAllister multibody interaction model was used to correlate the binary properties. These nonassociated and associated models were compared and tested for different systems showing that the associated processes yield fair agreement between theory and experiment compared with nonassociated processes.