One-pot three-component reaction of ninhydrin, 1,3-dicarbonyl compounds,and primary amines to afford indeno[1,2-b]pyrrol-4(1H)-ones

Chemistry of Heterocyclic Compounds - A convenient one-pot three-component synthesis of indeno[1,2-b]pyrrol-4(1H)-ones has been developed. The reaction of ninhydrin, 1,3-dicarbonyl compounds, and...     

Rapid microwave promoted heterocyclization of primary amines with triethyl orthoformate and sodium azide using zinc sulfide nanoparticles as recyclable catalyst

Microwave assisted synthesis of 1-substituted-1H-tetrazoles was developed using zinc sulfide nanoparticles as heterogeneous catalyst under solvent free conditions. The tetrazole derivatives were easily prepared through hterocyclization of primary amines with triethyl orthoformate and sodium azide in the presence of ZnS NPs. The experimental results were shown that a series of 1-substituted tetrazoles were synthesized under microwave irradiation by ZnS NPs as an effective and reusable heterogeneous catalyst in excellent yields. This protocol has advantages rather than other reported methods such as non-acidic catalyst, solvent free conditions and greener process as well as a solid recyclable catalyst. The catalyst was recovered and reused for several cycles with consistent activity.     

Connectionist intelligent model estimates of convective heat transfer coefficient of nanofluids in circular cross-sectional channels

Journal of Thermal Analysis and Calorimetry - The effect of Na2CO3 additive on the steam gasification characteristics of Sunjiahao (SJH) coal char was studied in the present paper. Na2CO3-catalyzed...     

Electrochemical and mechanical characteristics of Al-(x)SiC composite fabricated by high energy compaction

Simultaneous compaction and sintering using the energy generated by the underwater explosion is a rapid method that does not have the negative consequences of normal sintering, such as unwanted reactions between components and grain growth. For this reason, this study used the energy from this process to produce Al/SiC composites with different amounts of SiC. As a result, 10, 20, and 30% of SiC powder were added to the Al powder, and then the samples were produced by compression under the influence of an underwater explosion. The results showed that as the amount of SiC increased, the samples' density and the amount of porosity for further agglomeration increased. Microstructural examination by Scanning Electron Microscopy (SEM) confirmed the increase in agglomeration with increasing SiC. Besides, Samples experienced an increase in hardness as the amount of SiC raised. Adding 10% of SiC increased the flexural strength while adding more (20 and 30%) increased the agglomeration resulting in a decrease in strength and elongation. Polarization and impedance spectroscopy (EIS) methods were used to study the samples' electrochemical behavior in a 3.5% NaCl solution. Results showed that the addition of SiC particles up to 10% (wt%) reduces the corrosion density from 9.7 (μA/cm²) to 2.06 (μA/cm²). The Al–10%SiC composite had the lowest corrosion current density compared to 20% and 30% SiC composites. In addition, the polarization resistance of the Nyquist plot for pure Al and Al composite containing 10% SiC was 3965 and 7862, respectively. Therefore, these results showed the beneficial effect of 10% SiC as reinforcing particles on the corrosion behavior of Al composites and thus improved corrosion resistance.     

[Et3N-SO3H][MeSO3] as a highly efficient catalyst for the production of pyrido[2,3-d:6,5-d′]dipyrimidines and bis(pyrazolyl)methanes

Research on Chemical Intermediates - In this research, highly efficient protocols for the production of pyrido[2,3-d:6,5-d′]dipyrimidine and bis(pyrazolyl)methane derivatives using an acid...     

Efficient Synthesis of Polyhydroquinolines via the Hantzsch Reaction Using Iron Loaded Mesoporous Materials

A simple and convenient protocol is described for the preparation of polyhydroquinolines via one‐pot, multi component reaction of an aromatic aldehyde, ethylacetoacetate, ammonium acetate and dimedone using iron loaded mesoporous materials as an efficient catalyst in good yields.     

Selective solid phase extraction of palladium by adsorption of its 5(p-dimethylaminobenzylidene)rhodanine complex on silica-PEG as a new adsorbent

The nickel(II) complex of a deoxyribonucleic acid (DNA-Ni²⁺) was directly electrodeposited on the surface of a glassy carbon electrode (GCE) to give a DNA-Ni/GCE electrode. It was investigated in terms of its capability of electro-oxidizing methanol in alkaline medium. It exhibits stable redox behavior of the Ni²⁺/Ni³⁺ couple by cyclic voltammetry. The DNA-Ni²⁺ membrane showed excellent electrocatalytic suitability for the electro-oxidation of methanol, is stable and responds reproducibly. The linear range for the detection of methanol in alkaline medium is from 8.0 µM to 2.4 mM, and the limit of detection is 2.0 µM (at a signal-to-noise ratio of 3).     

Molecular Dynamics Simulation of the Ionic Liquid 1-n-Butyl-3-Methylimidazolium Methylsulfate [Bmim][MeSO4]: Interfacial Properties at the Silica and Vacuum Interfaces

Molecular dynamics simulations are done to investigate the structure and dynamics of a thin [Bmim][MeO₄] film in contact with a hydroxylated silica surface on one side and with vacuum on the other. An examination of the microscopic structure of ionic liquid (IL) film shows that strong layered anionic/cationic structures are formed at both interfaces. At the silica interface, the imidazolium rings are closer to the silica surface (compared to anions) and are coplanar with it. At the vacuum interface, the charged imidazolium ring more concentrates in the interior of the film, but the butyl side chain stretches out toward the vacuum interface. While there exists an excess concentration of the cations at the silica interface, at the vacuum interface an excess concentration of anions (dissolved in the butyl chain) is found. The influence of the interface on the dynamical properties is shown to depend on their time scales. A short-time dynamical property, such as hydrogen bond formation is not noticeably perturbed at the interface. In contrary, long-time properties such as ion-pair formation/rupture and translation of ions across the film are largely decelerated at the silica interface but are accelerate at the vacuum interface. Our findings indicate that the structural relaxation time of ion-pairs, is comparable to diffusion time scale in the IL film. Therefore, ion-pairs are not stable species; the IL is composed of short-lived ion-pairs and freely diffusing ions. However, the structural relaxation times of ion-pairs is still long enough (comparable to the time scale of diffusion) to conclude that correlated motions of counterions influence the macroscopic properties of IL, such as diffusion and ionic conductivity. In this respect, we have shown that correcting the Nernst-Einstein equation for the joint translation of ion-pairs considerably improves the accuracy of calculated ionic conductivities.     

二氧化硅包覆NiFe_2O_4担载Preyssler杂多酸用于合成双(二氢嘧啶酮)苯和3,4-二氢嘧啶-2(1H)-酮（英文）

A novel magnetic acidic catalyst comprising Preyssler(H14[Na P5W30O110]) heteropoly acid support‐ed on silica coated nickel ferrite nanoparticles (Ni Fe2O4@Si O2) was prepared.The catalyst was characterized by Fourier transform infrared,scanning electron microscopy,transmission electron microscopy,X‐ray diffraction,energy dispersive spectrum,VSM and particle size neasurement.Its catalytic activity was investigated for the synthesis of bis(dihydropyrimidinone)benzene and 3,4‐dihydropyrimidin‐2(1H)‐ones derivatives by the Biginelli reaction.With the catalyst,the reac‐tions occurred in less than 1 h with good to excellent yields.More importantly,the catalyst was easily separated from the reaction mixture by an external magnet and reused at least five times without degradation in the activity.     

One‐Pot Synthesis of Cu2O/ZnO Nanoparticles at Present of Folic Acid to Improve UV‐Protective Effect of Cotton Fabrics

In this study, the effect of using folic acid on the in situ synthesis process of nanostructures has been investigated. Folic acid, as a biotemplate for synthesis of Cu₂O/ZnO, was used to improve the reducing and stabilizing the ability of cotton fabric and avoid agglomeration of the particles. Scanning electron microscopy images revealed that using folic acid caused the formation of particles with smaller sizes on the cotton fabric and X‐ray diffraction confirmed the same crystalline pattern of nanoparticles in comparison with the previous synthesis process. The effect of using this biotemplate on different properties of treated fabrics including UV‐protection effect, hydrophilicity, crease recovery angle, softness, thickness and mechanical properties has been evaluated. The folic acid had a great influence on UV‐protection effect, in synthesis procedure, decreasing the droplet absorption time, bending length and improving the wrinkle resistance and mechanical properties. Interestingly, the higher tensile strength of the treated cotton fabrics proved the incorporation of nanoparticles into the cotton fibers. An in situ, green and rapid method can be provided by using folic acid for the synthesis of the nanostructures with controlled size.