scholarly journals Concentration and Temperature Dependence of the Thermodynamic Properties of Novel Biologically Active 3-Substituted Schiff Base of 4-Piperidyl N-(4-chlorophenyl)maleimide

2021 ◽  
Vol 33 (6) ◽  
pp. 1403-1408
Author(s):  
Jayraj Aher ◽  
Arun Bhagare ◽  
Manoj Gaware ◽  
Dnyaneshwar Lokhande ◽  
Anant Kardel ◽  
...  
Keyword(s):  
Free Energy ◽  
Schiff Base ◽  
Thermodynamic Properties ◽  
Temperature Dependence ◽  
Viscosity Coefficient ◽  
Biologically Active ◽  
Empirical Parameter ◽  
Solvent Interactions ◽  
Solute Interactions ◽  
Semi Empirical

In present work, the concentration and temperature dependence of the thermodynamic properties of 3-substituted Schiff base of 4-piperidyl N-(4-chlorophenyl)maleimide compound in 80% DMSO was estimated. Concentration (0.002-0.01 M) and temperature (298-313 K) dependent densitometric and viscometric measurement were employed to evaluate limiting molar volume (φv 0), semi-empirical parameter (Sv), Falkenhagen (A) and Jones-Dole (B) viscosity coefficient. The obtained results suggest the presence of weaker solute-solvent interactions and stronger solute-solute interactions. It was observed that these interactions strongly depend on the temperature of the system. Furthermore, the Gibbs free energy (ΔG), enthalpy (ΔH) and entropy (ΔS) of the system were also evaluated. The negative values of ΔG and ΔH and positive values of ΔS indicating reaction was spontaneous and exothermic in nature.

Determination of solute-solute and solute-solvent interaction of pyrimidine5-carbonitrile in aqueous DMSO at 298.15 K.

2020 ◽  
Vol 10 ◽  
Author(s):  
Jayraj S. Aher ◽  
Anant V. Kardel ◽  
Dnyneshawar D. Lokhande ◽  
Manoj R. Gaware ◽  
Arun M. Bhagare
Keyword(s):  
Molar Volume ◽  
Apparent Molar Volume ◽  
Solvent Interaction ◽  
Solvent Interactions ◽  
Aqueous Dmso ◽  
Viscosity Study ◽  
Solute Interactions ◽  
Semi Empirical ◽  
High Electronegativity

Introduction: In this reported work, we have used 80 % aqueous dimethyl sulphoxide (DMSO) for density and viscosity measurement of pyrimidine-5-carbonitrile at 298.15 K. The obtained experimental results shows that as concentration increases density and viscosity increases. From the results of density and viscosity, we have found apparent molar volume, limiting apparent molar volume, semi-empirical parameters, Falkenhagen coefficients and Jones Dole coefficients. Method: The apparent molar volume and limiting apparent molar volume having negative values indicated electostrictive solvation of ions and weak or absence of ion solvent interactions respectively. Result & Discussion : Falkenhagen coefficients is independent of concentration having positive value has shown strong solute-solute interactions and Jones-Dole coefficients having negative value has shown weak solute-solvent interactions. The strong solute-solute interactions were presents in A-1 as compared to A-2 compound because high electronegativity of oxygen atom. These parameters had given idea about molecular interactions such as solute-solute, solute-solvent and solvent-solvent. Conclusion: We have reported density and viscosity study of 4-amino-2-hydroxy-6-phenylpyrimidine-5-carbonitrile and 4- amino-2-mercapto-6-phenylpyrimidine-5-carbonitrile in 80 % aqueous DMSO solution at 298.15 K temperature. It has been observed that Strong molecular association in A-2 as compared to A-1 due to negative values of Øv.

scholarly journals First Principles Investigation on Thermodynamic Properties and Stacking Fault Energy of Paramagnetic Nickel at High Temperatures

Metals ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 319
Author(s):  
Jing Zhang ◽  
Pavel A. Korzhavyi
Keyword(s):  
Mechanical Properties ◽  
Free Energy ◽  
Thermodynamic Properties ◽  
Temperature Dependence ◽  
First Principles ◽  
Elastic Moduli ◽  
Stacking Faults ◽  
Lattice Parameter ◽  
Stacking Fault ◽  
Stacking Fault Energies

Reliable data on the temperature dependence of thermodynamic properties of alloy phases are very useful for modeling the behavior of high-temperature materials such as nickel-based superalloys. Moreover, for predicting the mechanical properties of such alloys, additional information on the energy of lattice defects (e.g., stacking faults) at high temperatures is highly desirable, but difficult to obtain experimentally. In this study, we use first-principles calculations, in conjunction with a quasi-harmonic Debye model, to evaluate the Helmholtz free energy of paramagnetic nickel as a function of temperature and volume, taking into account the electronic, magnetic, and vibrational contributions. The thermodynamic properties of Ni, such as the equilibrium lattice parameter and elastic moduli, are derived from the free energy in the temperature range from 800 to 1600 K and compared with available experimental data. The derived temperature dependence of the lattice parameter is then used for calculating the energies of intrinsic and extrinsic stacking faults in paramagnetic Ni. The stacking fault energies have been evaluated according to three different methodologies, the axial-next-nearest-neighbor Ising (ANNNI) model, the tilted supercell approach, and the slab supercell approach. The results show that the elastic moduli and stacking fault energies of Ni decrease with increasing temperature. This “softening” effect of temperature on the mechanical properties of nickel is mainly due to thermal expansion, and partly due to magnetic free energy contribution.

scholarly journals First-Principles Study of Mechanical and Thermodynamic Properties of Binary and Ternary CoX (X = W and Mo) Intermetallic Compounds

Materials ◽  
2021 ◽  
Vol 14 (6) ◽  
pp. 1404
Author(s):  
Yunfei Yang ◽  
Changhao Wang ◽  
Junhao Sun ◽  
Shilei Li ◽  
Wei Liu ◽  
...  
Keyword(s):  
Free Energy ◽  
Thermodynamic Properties ◽  
Gibbs Free Energy ◽  
Density Functional ◽  
Vibrational Entropy ◽  
Functional Theory ◽  
Lattice Constants ◽  
The Density Functional Theory ◽  
Ductile Behavior ◽  
Pseudo Potential

In this study, the structural, elastic, and thermodynamic properties of DO19 and L12 structured Co3X (X = W, Mo or both W and Mo) and μ structured Co7X6 were investigated using the density functional theory implemented in the pseudo-potential plane wave. The obtained lattice constants were observed to be in good agreement with the available experimental data. With respect to the calculated mechanical properties and Poisson’s ratio, the DO19-Co3X, L12-Co3X, and μ-Co7X6 compounds were noted to be mechanically stable and possessed an optimal ductile behavior; however, L12-Co3X exhibited higher strength and brittleness than DO19-Co3X. Moreover, the quasi-harmonic Debye–Grüneisen approach was confirmed to be valid in describing the temperature-dependent thermodynamic properties of the Co3X and Co7X6 compounds, including heat capacity, vibrational entropy, and Gibbs free energy. Based on the calculated Gibbs free energy of DO19-Co3X and L12-Co7X6, the phase transformation temperatures for DO19-Co3X to L12-Co7X6 were determined and obtained values were noted to match well with the experiment results.

scholarly journals Synthesis and Evaluation of Schiff Bases of 4-Amino-5-(chlorine substituted phenyl)-4H-1,2,4-triazole-3-thione as Antimicrobial Agents

2020 ◽  
Vol 41 (1) ◽  
pp. 26-35
Author(s):  
Kishor Devkota ◽  
Govinda Pathak ◽  
Bhushan Shakya
Keyword(s):  
Schiff Base ◽  
Schiff Bases ◽  
Antimicrobial Agents ◽  
Triazole Ring ◽  
Antimicrobial Activities ◽  
Biologically Active ◽  
Spectral Techniques ◽  
Schiff Base Derivatives ◽  
Bacteria And Fungi ◽  
Different Strains

Triazole ring system has attracted a continuously growing interest of synthetic organic chemists and those dealing with the medicinal compounds due to its versatile potential to interact with biological systems. Schiff bases are also considered as one of the most biologically active compounds.  The aim of the present study was to synthesize new Schiff bases bearing triazole nucleus and to assess their antimicrobial activities. Four new Schiff base derivatives of 1,2,4-triazole-3-thione were synthesized by combining two different pharmacophores viz. triazole nucleus and Schiff base moiety and were characterized by spectral techniques (UV, FT-IR, and NMR). The Schiff bases were evaluated for antibacterial (Staphylococcus aureus, Escherichia coli, and Klebsiella pneumoniae) and antifungal (Candida albicans) activities. The synthesized compounds exhibited good to moderate activities against different strains of bacteria and fungi tested.

scholarly journals Kinetics and thermodynamic properties related to the drying of 'Cabacinha' pepper fruits

2016 ◽  
Vol 20 (2) ◽  
pp. 174-180 ◽  
Author(s):  
Hellismar W. da Silva ◽  
Renato S. Rodovalho ◽  
Marya F. Velasco ◽  
Camila F. Silva ◽  
Luís S. R. Vale
Keyword(s):  
Experimental Data ◽  
Activation Energy ◽  
Free Energy ◽  
Thermodynamic Properties ◽  
Gibbs Free Energy ◽  
Removal Rate ◽  
Effective Diffusion ◽  
Drying Time ◽  
Three Samples ◽  
Different Temperatures

ABSTRACT The objective of this study was to determine and model the drying kinetics of 'Cabacinha' pepper fruits at different temperatures of the drying air, as well as obtain the thermodynamic properties involved in the drying process of the product. Drying was carried out under controlled conductions of temperature (60, 70, 80, 90 and 100 °C) using three samples of 130 g of fruit, which were weighed periodically until constant mass. The experimental data were adjusted to different mathematical models often used in the representation of fruit drying. Effective diffusion coefficients, calculated from the mathematical model of liquid diffusion, were used to obtain activation energy, enthalpy, entropy and Gibbs free energy. The Midilli model showed the best fit to the experimental data of drying of 'Cabacinha' pepper fruits. The increase in drying temperature promoted an increase in water removal rate, effective diffusion coefficient and Gibbs free energy, besides a reduction in fruit drying time and in the values of entropy and enthalpy. The activation energy for the drying of pepper fruits was 36.09 kJ mol-1.

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