scholarly journals Molecular modeling studies of HIV-1 non-nucleoside reverse transcriptase inhibitors using 3D-QSAR, virtual screening, and docking simulations

2019 ◽  
Vol 84 (3) ◽  
pp. 303-316 ◽  
Author(s):  
Jian-Bo Tong ◽  
Shang-Shang Qin ◽  
Shan Lei ◽  
Yang Wang
Keyword(s):  
Acetic Acid ◽  
3D Qsar ◽  
Entropy Change ◽  
Poly Vinyl Alcohol ◽  
Viscosity Data ◽  
Solvent Mixtures ◽  
Solvent Interactions ◽  
Docking Simulations ◽  
Different Temperatures ◽  
Increasing Temperature

The ionic-interactions of acetic acid in H2O?PVOH and H2O?alcohol? PVOH solvent systems were studied at different temperatures by the viscosity method. The viscosities of the poly(vinyl alcohol) (PVOH) were increased with increasing concentration of PVOH and decreased with the increasing concentration of acetic acid. The viscosity data were used to evaluate the ion?ion interactions and ion?solvent interactions in terms of the A and B coefficients of the Jones?Dole equation, respectively. The negative values of the B-coefficient increased with increasing temperature, showing that the acid behaves as a structure breaker in PVOH?solvent mixtures and consequently, the values of the A-coefficient were decreased with increasing temperature. Thermodynamic parameters, such as energy of activation (Ea*), Gibbs energy change of activation (?G*) and entropy change of activation (?S*) were also calculated as a function of the acid (CH3COOH) concentration, PVOH composition, alcohols and temperature.

scholarly journals Ionic-interaction of aqueous and alcoholic poly(vinyl alcohol) in the presence of protons

2019 ◽  
Vol 84 (3) ◽  
pp. 317-326
Author(s):  
Saima Naz ◽  
Rehana Saeed
Keyword(s):  
Acetic Acid ◽  
Vinyl Alcohol ◽  
Entropy Change ◽  
Poly Vinyl Alcohol ◽  
Viscosity Data ◽  
Solvent Mixtures ◽  
Solvent Interactions ◽  
Ion Interactions ◽  
Alcohol Solvent ◽  
Different Temperatures

The ionic-interactions of acetic acid in H2O-PVOH and H2O-Alcohol-PVOH solvent systems were studied at different temperatures by viscosity method. The viscosities of the poly(vinyl alcohol) were increased with the increase in the concentration of poly(vinyl alcohol) and decreased with the increase in the concentration of acetic acid. The viscosity data were used to evaluate the ion-ion interactions and ion-solvent interactions in terms of ?A? and ?B? coefficients of the Jones-Dole equation respectively. The negative values of B-coefficient increased with increase in temperature showed that acid behaves as structure breaker in poly(vinyl alcohol)-solvent mixtures and consequently the values of A-coefficient were decreased with the rise of temperature. Thermodynamic parameters such as energy of activation (Ea*), free energy change of activation (?G*) and entropy change of activation (?S*) were also calculated as a function of acid (CH3COOH) concentration, poly(vinyl alcohol) composition, alcohols, and temperature.

scholarly journals Study of Physical Properties for Sodium acetate with Water and Water - Acetone mixtures at Different Temperatures

2017 ◽  
Vol 27 (4) ◽  
Author(s):  
Ahmed Mohammed Abbas ◽  
Zainab Wajdi Ahmed ◽  
Alaa Fadhil Sulaiman ◽  
Issam AbdalKreem AbdalLatif
Keyword(s):  
Sodium Acetate ◽  
Apparent Molal Volume ◽  
Viscosity Data ◽  
Partial Molal Volume ◽  
Molal Volume ◽  
Solvent Interactions ◽  
Acetone Water ◽  
Thermodynamic Activation Parameter ◽  
Different Temperatures ◽  
Apparent Molal Compressibility

In this study binary and ternary solutions are prepared by using the sodium acetate concentrations (0.1, 0.125, 0.2, 0.25, 0.4, 0.5, 0.8, 1 M) in water and acetone –water mixtures .The important parameters such as apparent molal volume, the partial molal volume transfer,  apparent  molal compressibility, free energy of activation of viscous flow and thermodynamic activation parameter (enthalpy and entropy) determined of sodium acetate in water , 20%, 40% ,60% and 80% V/V acetone –water mixtures at 298.15K, 303.15K, and 308.15K from density and viscosity measurements espectively. The limiting apparent molal volumes and experimental slopes were derived from the Masson equation, have been interpreted in terms of solute–solvent and solute–solute interactions  respectively. The viscosity data were analyzed using theJones–Dole equation and the derived parameter B - coefficient has also been interpreted in terms of solute–solvent interactions in the solutions. 

An intensive study on the AC impedance mechanism of (AgPO3)1-x(Ag2SO4)x ionic glass systems under various conditions

2019 ◽  
Vol 16 (4) ◽  
pp. 477-486
Author(s):  
Atif Alkhazali ◽  
Morad Etier ◽  
Mohammad Aljarrah ◽  
Akram Alsukker ◽  
Fathy Salman
Keyword(s):  
Complex Impedance ◽  
Entropy Change ◽  
Impedance Analysis ◽  
Cole Plot ◽  
X Ray Diffraction ◽  
Content Type ◽  
Activation Free Energy ◽  
Complex Impedance Analysis ◽  
Different Temperatures ◽  
Increasing Temperature

Purpose The purpose of this study is to investigate the effect of the considerable Ag2SO4 content on the electrical and dielectric properties of (AgPO3)1−x(Ag2SO4)x ion glass system as well as to extract thermodynamic parameters. Design/methodology/approach Glass samples of (AgPO3)1-x(Ag2SO4)x with different mole ratios of Ag2SO4 [x = 0.00, 0.10,0.15,0.20 and 0.25] have been synthesized and used. X-ray diffraction and differential thermal analysis were used to investigate structural and thermal properties, and then the electrical characterizations of the bulk glasses were performed in different frequency and temperature range. Findings For different ratios of Ag2SO4 on AgPO3, the bulk conductivity is enhanced with increasing the amount of Ag2SO4 until the composition of x = 0.20, after which the conductivity decreases. The general behavior of both ε’ and ε” decreases with increasing frequency and increases with increasing temperature. Complex impedance analysis studied by Z‘−Z’ and Cole–Cole plot at different temperatures revealed that bulk resistance decreases with temperature. Originality/value The calculated values of activation free energy, enthalpy and entropy change for different compositions of (AgPO3)1-x(Ag2SO4)x showed an increase in activation energy and enthalpy when Ag2SO4 ratio is increased in (AgPO3)1-x(Ag2SO4)x composition up to 20%, and then there is a decrease in their values at x = 25%, which may be explained based on non-bridging oxygen.

scholarly journals Study of Acoustic Nature of Tetrapentylammonium Bromide in N,N-Dimethyl-Ethylmethyl Ketone Systems at Different Temperatures

2015 ◽  
Vol 48 ◽  
pp. 103-113
Author(s):  
Baljeet Singh Patial
Keyword(s):  
Relaxation Time ◽  
Internal Pressure ◽  
Ultrasonic Velocity ◽  
Acoustic Impedance ◽  
Adiabatic Compressibility ◽  
Solvent Mixtures ◽  
Density Data ◽  
Solvent Interactions ◽  
Intermolecular Free Length ◽  
Different Temperatures

Ultrasonic velocity, viscosity and density studies on solution of tetrapentylammonium bromide (Pen4NBr) in N,N-dimethylformamide, ethylmethylketone (EMK) and DMF-EMK solvent mixtures containing 0, 20, 40, 60, 80 and 100 mol % of DMF at 298, 308 and 318K have been reported. From the velocity, viscosity and density data values, various parameters namely, the adiabatic compressibility (β), Intermolecular free length (Lf), specific acoustic impedance (Z), free volume (Vf), internal pressure (πi) and relaxation time (τ) have been calculated. All these parameters have been discussed separately to throw light on the solute-solvent and solvent-solvent interactions.

Viscometric Study of n-Hexylammonium and n-Octylammonium perchlorates in Binary Non-Aqueous Solvents Probed by a Physicochemical Approach in the Temperature Ranging 298 - 328K at Atmospheric Pressure

2021 ◽  
Vol 37 (3) ◽  
pp. 656-662
Author(s):  
Vivek Pathania ◽  
Shrutila Sharma ◽  
S.K. Vermani ◽  
B.K. Vermani ◽  
Navya Grover ◽  
...  
Keyword(s):  
Entropy Change ◽  
State Theory ◽  
Viscosity Data ◽  
Solvent Interaction ◽  
Solvent Interactions ◽  
Ion Interactions ◽  
Enthalpy And Entropy ◽  
Viscometric Study ◽  
B Coefficients ◽  
Physicochemical Approach

Viscosity data were measured for n-hexyl ammonium perchlorate (C6H13NH3ClO4)(HAP) and n-octylammonium perchlorate (C8H17NH3ClO4) (OAP) in acetonitrile (AN), dimethylsulfoxide (DMSO) and their binary mixtures containing 0, 20, 40, 60, 80 and 100 mol%DMSO at 298, 308, 318 and 328 K in the concentration range 60-350×10-4 mol.dm-3. The data was further examined to evaluate ion-ion and ion-solvent interactions in terms of the Aand B coefficients of the Jones-Dole equation respectively. A and B coefficients for the studied electrolytes came out be to be positive throughout the whole composition range. However, smaller values of A as compare to B reveal the dominance of ion-solvent interaction over ion-ion interactions especially at 60 mol% DMSO in AN-DMSO mixtures. Thermodynamic parameters like free energy, enthalpy and entropy change of activation of the viscous flow have also been evaluated by using Erying transition state theory.

Thermodynamic study of poly(ethylene glycol) in water/acetone solutions by viscometry

2011 ◽  
Vol 31 (5) ◽  
Author(s):  
Abbas Mehrdad ◽  
Mohammad Taghi Taghizadeh ◽  
Roghieh Moladoust
Keyword(s):  
Ethylene Glycol ◽  
Polymer Chains ◽  
Viscosity Data ◽  
Poly Ethylene Glycol ◽  
Solvent Interaction ◽  
Solvent Interactions ◽  
Volume Fractions ◽  
Poly Ethylene ◽  
Increasing Temperature ◽  
Mixed Water

Abstract In this work, the intrinsic viscosities of poly(ethylene glycol) (PEG) with a molar mass of 20,000 g·mol-1 were measured in water/acetone solutions from (283.1 to 313.1) K. The expansion factors of the polymer chains were calculated from the intrinsic viscosity data. The thermodynamic para­meters (entropy of dilution parameter, the heat of dilution para­meter, θ temperature, polymer-solvent interaction parameter and second osmotic virial coefficient) were derived by the temperature dependence of the polymer chain expansion factor. The thermodynamic parameters indicate that mixtures of water/acetone are changed to the poorer solvents for PEG, by increasing temperature and volume fractions of acetone. Also, the temperature dependency of segment-segment and segment-solvent interactions for PEG in mixed water/acetone, is decreased by increasing volume fractions of acetone.

Revisiting Glycerol Esterification with Acetic Acid over Amberlyst-35 via Statistically Designed Experiments: Overcoming Transport Limitations

2019 ◽  
Author(s):  
Víctor Gabriel Baldovino Medrano ◽  
Karen V. Caballero ◽  
Hernando Guerrero-Amaya
Keyword(s):  
Acetic Acid ◽  
Active Sites ◽  
Batch Reactor ◽  
Catalyst Particle ◽  
Experimental Designs ◽  
Particle Sizes ◽  
Turnover Rates ◽  
Designed Experiments ◽  
Different Temperatures ◽  
Glycerol Esterification

Turnover rates for glycerol esterification with acetic acid over Amberlyst-35 were measured under different temperatures, reactants and active sites concentrations, and catalyst particle sizes. Data were collected in a batch reactor. Experiments were done following a sequence of factorial experimental designs.

Excess molar volumes of binary mixtures of acetic acid and propionic acid with some members of homologous series of alkanes

1991 ◽  
Vol 56 (4) ◽  
pp. 736-744 ◽  
Author(s):  
Ondřej Drábek ◽  
Ivan Cibulka
Keyword(s):  
Acetic Acid ◽  
Propionic Acid ◽  
Alkyl Chain ◽  
Excess Molar Volumes ◽  
Liquid Mixtures ◽  
Entire Concentration Range ◽  
Molar Volumes ◽  
Binary Liquid ◽  
Alkane Molecule ◽  
Increasing Temperature

Excess molar volumes of binary liquid mixtures of (acetic or propionic acid = hexane) at 25 and 35°C, and (acetic or propionic acid + heptane or octane) and (acetic acid + dodecane) at 25°C, measured with a tilting dilution dilatometer, are reported. The excess volumes are positive over the entire concentration range for all mixtures and increase with increasing length of an alkane molecule, decrease with increasing of the alkyl chain in a molecule of carboxylic acid, and increase with increasing temperature.

scholarly journals A Comparative Electrochemical and Morphological Investigation on the Behavior of NiCr and CoCr Dental Alloys at Various Temperatures

Metals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 256
Author(s):  
Florentina Golgovici ◽  
Mariana Prodana ◽  
Florentina Gina Ionascu ◽  
Ioana Demetrescu
Keyword(s):  
Low Temperatures ◽  
Artificial Saliva ◽  
Electrochemical Stability ◽  
Morphological Investigation ◽  
Dental Alloys ◽  
Ion Release ◽  
Icp Ms ◽  
Different Temperatures ◽  
Good Concordance ◽  
Increasing Temperature

The purpose of our study is to compare the behavior of two reprocessed dental alloys (NiCr and CoCr) at different temperatures considering the idea that food and drinks in the oral cavity create various compositions at different pH levels; the novelty is the investigation of temperature effect on corrosion parameters and ion release of dental alloys. Electrochemical stability was studied together with morphology, elemental composition and ions release determination. The results obtained are in good concordance: electrochemistry studies reveal that the corrosion rate is increasing by increasing the temperature. From SEM coupled with EDS, the oxide film formed on the surface of the alloys is stable at low temperatures and a trend to break after 310K. ICP-MS results evidence that in accordance with increasing temperature, the quantities of ions released from the alloys immersed in artificial saliva also increase, though they still remain small, less than 20 ppm.

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