Zn/MCM-41-catalyzed unsymmetrical Hantzsch reaction and the evaluation of optical properties and anti-cancer activities of the polyhydroquinoline products

The three-component Hantzsch condensation of various aryl aldehydes, dimedone, and methyl 3-aminocrotonate was investigated in the presence of MCM-41-supported ZnNO3. The polyhydroquinoline products which were obtained under mild conditions and very easy workup were evaluated for anti-cancer activities against MCF-7, SK-BR-3, and HT-29 of breast and colon cancer cells. The fluorescence emission of some products was also studied and their optical parameters were reported.     

Au‐dimercaprol functionalized cellulose aerogel: Synthesis,characterization and catalytic application

A new derivative of cellulose aerogel was prepared via functionalization of cellulose with dimercaprol. Dimercaprol, as a chelating agent of Au(III), was applied for the loading of Au(III) on cellulose aerogel. The new organogold compound after characterization was used as an efficient heterogeneous catalyst in the oxidation reactions of aliphatic alcohols, benzyl alcohol, and ethylbenzene. Excellent selectivities and good conversions were obtained in the green oxidation reactions of alcohols and ethylbenzene. The high porosity of cellulose aerogel led to the good conversions with the low catalyst amounts. The significance of the presented work is the introducing of an environmentally benign process for the oxidation reactions based on a biocompatible catalyst.     

Synthesis and catalytic application of Pd/PdO/Fe3O4@polymer-like graphene quantum dots

A novel approach was achieved for growing citric acid towards polymer-like graphene quantum dots (PGQD) with high efficiency in the presence of sodium hydroxide as a base catalyst. This protocol is completely safe, simple, fast, and efficient by a bottom up strategy. Thermal treatment of a mixture containing citric acid with NaOH at 300 °C gave PGQD during 5 min. The reaction afforded a new heterogeneous catalyst, Pd/PdO/Fe₃O₄@PGQD, in the presence of Pd and Fe₃O₄. The magnetically recoverable catalyst showed high activity in the oxidation of alkylarenes and alcohols using H₂O₂ as a green oxidant at room temperature. Comparison of the results with previous reports showed the efficiency of the catalyst to have high turnover numbers in mild reaction conditions.     

Microwave-assisted aldol condensation of benzil with ketones

Under microwave irradiation,the corresponding hydroxycyciopentenones were prepared in high yields by the cross-aldol reactions of benzil with various ketones.When the reactions were performed in vailOUS solvents under classical heating for a long time,they produced the products in relatively low yields.     

Constraint Qualifications and Stationary Conditions for Mathematical Programming with Non-differentiable Vanishing Constraints

This paper aims at studying a broad class of mathematical programming with non-differentiable vanishing constraints. First, we are interested in some various qualification conditions for the problem. Then, these constraint qualifications are applied to obtain, under different conditions, several stationary conditions of type Karush/Kuhn–Tucker.     

Computational Study on Interactions between CO2 and (TiO2)n Clusters at Specific Sites

The energetic pathways of adsorption and activation of carbon dioxide (CO₂) on low-lying compact (TiO₂)_n clusters are systematically investigated by using electronic structure calculations based on density-functional theory (DFT). Our calculated results show that CO₂ is adsorbed preferably on the bridge O atom of the clusters, forming a "chemisorption" carbonate complex, while the CO is adsorbed preferably to the Ti atom of terminal Ti-O. The computed carbonate vibrational frequency values are in good agreement with the results obtained experimentally, which suggests that CO₂ in the complex is distorted slightly from its undeviating linear configuration. In addition, the analyses of electronic parameters, electronic density, ionization potential, HOMO-LUMO gap, and density of states (DOS) confirm the charge transfer and interaction between CO₂ and the cluster. From the predicted energy profiles, CO₂ can be easily adsorbed and activated, while the activation of CO₂ on (TiO₂)_n clusters are structure-dependent and energetically more favorable than that on the bulk TiO₂. Overall, this study critically highlights how the small (TiO₂)_n clusters can influence the CO₂ adsorption and activation which are the critical steps for CO₂ reduction the surface of a catalyst and subsequent conversion into industrially relevant chemicals and fuels.     

Nonlinear excitation and stability analysis of ion-acoustic waves in a magnetized quantum plasma with exchange-correlation effects of degenerate electrons

The nonlinear ion-acoustic wave excitation and its stability analysis are investigated in a magnetized quantum plasma with exchange-correlation and Bohm diffraction effects of degenerate electrons in the model. Using reductive perturbation technique, the Zakharov-Kuznetsov (ZK) equation is derived for two dimensional propagation of ion-acoustic wave in a magnetized quantum plasma. It is found that the phase speed, amplitude and width of the nonlinear ion-acoustic wave structures are affected in the presence of exchange-correlation potential in the model. The stability analysis of the 2D ion-acoustic wave pulse is also presented. It is found that growth rate of the first and second order instabilities of 2D ion acoustic wave soliton is enhanced with the inclusion of exchange-correlation potential effect in the model.     

Thermo-bioconvection transport of nanofluid over an inclined stretching cylinder with Cattaneo–Christov double-diffusion

In this paper, Newtonian nanofluid flow is observed under the effects of the magnetic field, activation energy and motile microorganisms over an inclined stretchable cylinder. The magnificent aspects of nanoliquid are demonstrated by enduring the Brownian motion and thermophoresis diffusion features.Nonlinear higher order partial differential equations are transformed into first-order ordinary differential equations with suitable similarity variables. The attained sets of governing equations are then cracked by bvp4 c procedure in MATLAB mathematical software. The numerical and graphical outcomes of controlling parameters such as Prandtl number, mixed convection, activation energy, thermophoresis,Brownian parameter, Biot number, Lewis number, Peclet number and motile concentration parameter against the velocity, temperature, volumetric concentration and motile concentration of nanoparticles of the fluid are discussed. The velocity is enhanced with the growth valuation in mixed convection and decay by rising variation of buoyancy ratio parameter, magnetic parameter and bio-convective Rayleigh parameter. The evolution in motile microorganisms is due to the increasing values of microorganisms Biot number. The presented data can be helpful in enhancement of manufacturing processes, biomolecules, extrusion systems applications and energy production improvement.     

Synthesis of novel ZnAl2O4/Al2O3 nanocomposite by sol–gel method and its application as adsorbent

Journal of Sol-Gel Science and Technology - In this research, ZnAl2O4/Al2O3 nanocomposites with different ZnAl2O4 (30, 50, and 70?wt.%) were successfully prepared in one step by sol–gel...