Synthesis of Diaryl Ethers Through the Copper-Catalyzed Arylation of Phenols with Aryl Iodides Using KF/Al2O3

An efficient synthesis of diaryl ethers by the copper-catalyzed arylation of phenols with a variety of aryl iodide susing KF/Al₂O₃ as a suitable base and CuI and 1,3 diphenyl-1,3 propandione as the catalyst is described.     

NON-LINEAR FREE VIBRATION ANALYSIS OF A STRING UNDER BENDING MOMENT EFFECTS USING THE PERTURBATION METHOD

In this paper, the non-linear free vibration of a string with large amplitude is considered. The initial tension, lateral vibration amplitude, cross-section diameter and the modulus of elasticity of the string have main effects on its natural frequencies. Increasing the lateral vibration amplitude makes the assumption of constant initial tension invalid. Therefore, it is impossible to use the classical equation of transverse motion assuming a small amplitude. On the other hand, by increasing the string cross-sectional diameter, the bending moment effect will increase dramatically, and it will act as an impressive restoring moment. Considering the effects of the bending moments, the non-linear equation governing the large amplitude transverse vibration of a string is derived. The time-dependent portion of the governing equation has the form of the Duffing equation. Due to the complexity and non-linearity of the derived equation and the fact that there is no established exact solution method, the equation is solved using the perturbation method. The results of the analysis are shown in appropriate graphs, and the natural frequencies of the string due to the non-linear factors are compared with the natural frequencies of the linear vibration of a string without bending moment effects.     

Induced photonuclear interaction by Rhodotron-TT200 10 MeV electron beam

In this paper the photonuclear interaction induced by 10 MeV electron beam generating high-intensity neutrons is studied. Since the results depend on the target material, the calculations are performed for Pb, Ta and W targets which have high Z, in a simple geometry. MCNPX code has been used to simulate the whole process. Also, the results of photon generation has been compared with the experimental results to evaluate the reliability of the calculation. The results show that the obtained neutron flux can reach up to 10¹² n/cm²/s with average energies of 0.9 MeV, 0.4 MeV and 0.9 MeV for these three elements respectively with the maximum heat deposited as 3000 W/c³, 4500 W/c³ and 6000 W/c³.     

二氧化钛纳米粒子催化合成Hantzsch酯和多氢喹啉衍生物(英文)

1,4-Dihydropyridine and polyhydroquinoline derivatives have been prepared efficiently in a one-pot synthesis via Hantzsch condensation using nanosized titanium dioxide as a heterogeneous catalyst.The present methodology offers several advantages such as excellent yields,short reaction times (30-120 min),environmentally benign,and mild reaction conditions.The catalyst can be readily separated from the reaction products and recovered in excellent purity for direct reuse.     

Synthesis of phthalazine compounds using heterogeneous base catalyst based on silica nanoparticles obtained from rice husk

Research on Chemical Intermediates - In this study, the nanoparticles of amorphous silica were easily extracted from low-cost rice husk ash. They were functionalized with 3-(chloropropyl)...     

H3PW12O40催化水相介质中苯并恶嗪和喹唑啉合成（英文）简

A heteropolyacid efficiently catalyzed the cyclocondensation reaction of 2-aminobenzamide and salicylamide with aldehydes and ketones to afford good yields of benzoxazine and quinazoline ring systems in an aqueous medium. The method gives clean reactions, has simple workup procedure, and uses environment friendly conditions.     

Nanosilica-bonded <Emphasis Type="Italic">N</Emphasis>-(propylsulfonyl) piperazine-<Emphasis Type="Italic">N</Emphasis>-sulfamic acid as recyclable catalyst for synthesis of 1,1′-(arylmethylene) diureas and 1,3,5-triazinane-2,4-dithiones

Nanosilica-bonded N-(propylsulfonyl) piperazine-N-sulfamic acid was easily prepared by functionalizing silica nanoparticles and characterized by thermogravimetric analysis, scanning electron microscopy, infrared (IR) spectroscopy, elemental analyses, and ion-exchange pH analysis. The catalytic activity of the functionalized nanosilica for preparation of 1,1′-(arylmethylene) diureas from reaction of aldehydes with urea derivatives was examined. The efficient effect of this catalyst led to preparation of 1,1′-(arylmethylene) diureas in high yield. The reaction of aldehydes with thiourea under the same reaction conditions afforded high yield of 1,3,5-triazinane-2,4-dithiones. Catalyst reusability, simple workup procedure, and short reaction time are other advantages of this protocol.     

Synthesis of the acid–base bifunctional hybrid catalyst via covalently anchored organomoieties on to the SBA-15: a recyclable catalyst for the one‐pot preparation of 1‐amidoalkyl‐2‐naphthols

Research on Chemical Intermediates - In this research, SBA-amino-amido-carboxylic acid (SBA-NH-NHCO-COOH) is synthesized by nucleophilic substitution of SBA propylchloride (SBA-Cl) with ethylene...