Studies on excess molar volumes and viscosity deviations of binary mixtures of household kerosene and premium motor spirit at 303K

Density and viscosity of binary liquid mixtures of household kerosene (HHK) and premium motor spirit (PMS) were determined over the entire range of mole fraction at 303K. Excess molar volume (VE), molar volume (Vm), Excess Viscosity (ηE), Viscosity deviations (Δη) and excess Gibbs free energies of activation of viscous flow (ΔGE) were calculated. The results obtained shows that excess free energy of activation were all positive over the entire mole fraction. The viscosity deviation shows both negative and positive values. The positive VE obtained in this study shows increase in volume in the binary mixture. This work will help in effective monitoring, detection of adulterated kerosene and subsequent enforcement of severe penalty on such adulteration.

Performance Mechanism of Hydrogel for Enhanced Oil Recovery: A Numerical Simulation Study Based on the Phase-Field Approach

Hydrogels are increasingly applied in oil recovery processes. This leads to more controlled flow of fluids in porous media. In this process, hydrogel is injected to the reservoir to block the high permeability areas. The trapped oil in low permeability regions, is then swept by water flooding. pH-sensitive hydrogel microspheres were synthesized in another work of the authors, which effectively increased the oil recovery factor in experimental studies. In this communication, phase-field approach was used to simulate this process and to obtain the tuning parameters of the model including thickness of the contact surface(є), phase transform parameter(M0), excess free energy(\(\wedge\)), and interfacial tension. Diffusion of hydrogels was studied by Cahn–Hilliard conservative approach and the breakage, deformation, and plugging mechanisms were analyzed, based on pressure drop variations in micromodel. Moreover, Effective parameters on oil recovery factor were analyzed. Results indicated a good agreement between experimental and modeling studies of oil recovery factor in water and hydrogel flooding with absolute errors of 2.29% and 4.06%, respectively. The recovery factor was calculated using a statistical method which was in good agreement with the modeling results. The tuned parameters of the model were reported as, є= 111.7µm, M0= 5*10-13m3/s, \(\wedge\)=-0.0003 J/m3, and δ = 2×10-5 Pa.s.

Evaluation of viscosity in binary mixtures of dimethyl sulphoxide at 298.15K

The viscosity of binary mixtures of dimethyl sulphoxide with different alcohols such as methanol, ethanol, 1-propanol, iso-propanol, 1-butanol, iso-butanol, tertiary butanol has been determined at 298.15K. The experimental values are compared with theoretical values evaluated by different theories. It is observed that for some theories, values are in agreement with the experimental values. Further, an attempt has been made to study the intermolecular interactions in studied solutions in terms of excess free energy of mixing, strength of interaction parameters and interaction energy. The viscosity data of pure liquids and their mixtures are needed to design various chemical processes where heat and mass transfer are important.

Influence of solvent structure and hydrogen bonding on catalysis at solid–liquid interfaces

A pedagogical review that deconvolutes the excess free energy effects of several solvent phenomena and connects findings across a variety of catalytic reactions and materials.

Theoretical insights into C–H bond activation of methane by transition metal clusters: the role of anharmonic effects

To incorporate the anharmonicity in the vibrational free energy contribution to the configurational entropy, we evaluate the excess free energy of clusters numerically by a thermodynamic integration method with ab initio molecular dynamics (aiMD) simulation inputs.

Surface Properties of Al–Fe–Si Liquid Alloy Using Thermodynamic Database

Temperature-dependent interaction parameters for excess free energies of mixing of sub-binary systems of Al-Fe-Si ternary liquid alloys were optimised using the experiment data in the frame of Redlich-Kister (R-K) polynomials. These optimised parameters were then used to compute the partial excess free energy of sub-binary and ternary liquid alloys. The surface tension and surface concentration of sub-binary and the ternary liquid alloys were computed using Butler equation. The temperature dependent coefficients of R-K polynomials for excess surface tensions of the sub-binary systems were optimised which were then used to estimate the surface tension of ternary alloy using Chou, Kohler and Toop modelling equations at temperatures 1773, 1873, 1973 and 2073 K. The surface tension of the ternary alloy obtained using aforementioned models were found to be in good agreement from Fe and Al corners but some deviations were observed from Si corner.

A simple theory of mixtures for the study of the temperature dependence of thermo-structural properties of Al-Ga liquid alloy

A simple theory of mixtures for symmetric alloys was used to study the thermodynamic and structural properties of the Al-Ga alloy in the liquid state at 1023 K. The computed thermodynamic properties are in a very good agreement with the observed values and show that the alloy is weakly interacting. The computed structural properties show that the Al-Ga alloy is segregating in nature which is in agreement with the observed values. The excess free energy of mixing, activity of monomers and concentration fluctuation in the long wavelength limit was extrapolated to higher temperatures by optimising the temperature dependent parameters. As the temperature increases, the behaviour of the alloy shifts towards the ideality.