Zinc polyoxometalate on activated carbon: an efficient catalyst for selective oxidation of alcohols with hydrogen peroxide

[PW₁₁ZnO₃₉]^5? was immobilized on activated carbon and characterized using Fourier transform infrared, X‐ray diffraction, Brunauer–Emmett–Teller and elemental analysis techniques. Effective oxidation of various alcohols with hydrogen peroxide was performed in the presence of this catalyst. Easy separation of the catalyst from the reaction mixture, cheapness, high activity and selectivity, stability as well as retained activity in subsequent catalytic cycles make this supported catalyst suitable for small‐scale synthesis. Copyright © 2015 John Wiley & Sons, Ltd.     

Rapid and efficient synthesis of 2-imidazolines and bis-imidazolines under ultrasonic irradiation

Rapid and efficient preparation of 2-imidazolines and bis-imidazolines by reaction of ethylenediamine with nitriles in the presence of catalytic amounts of sulfur under ultrasonic irradiation is reported. The advantages of this system are short reaction times, high yields and the ability to carry out large scale reactions.     

Efficient regio- and stereoselective ring opening of epoxides with alcohols, acetic acid and water catalyzed by ammonium decatungstocerate(IV)

Epoxides can be cleaved in a regio- and stereoselective manner under neutral conditions with alcohols and acetic acid in the presence of catalytic amounts of decatungstocerate(IV) ion, ([CeW₁₀O₃₆]⁸⁻), affording the corresponding β-alkoxy and β-acetoxy alcohols in high yields. In water, ring opening of epoxides occurs with this catalyst to produce the corresponding diols in good yields.     

Chemical composition and antimicrobial activity of the essential oils of Ferula latisecta and Mozaffariania insignis from Iran

The hydrodistilled oils from the aerial parts of Ferula latisecta and Mozaffariania insignis, which is endemic to Iran, were analyzed by GC and GC/MS. (Z)-Ocimenone (32.4%), (E)-ocimenone (20.3%), and cis-pinocarvone (11.4%) were the main components among the 22 constituents characterized in the oil of F. latisecta, representing 87.7% of the total components detected. Twenty-five compounds were identified in the oil of M. insignis, representing 99.0% of the total oil, with octyl acetate (41.1%), β-pinene (30.3%), and α-pinene (23.9%) as the main constituents. The essential oils were examined for their potential antimicrobial activities. Published in Khimiya Prirodnykh Soedinenii, No. 6, pp. 561–563, November–December, 2006.     

Engineering a Cu‐MOF Nano‐Catalyst by using Post‐Synthetic Modification for the Preparation of 5‐Substituted 1H‐Tetrazoles

A new nano scale Cu‐MOF has been obtained via post‐synthetic metalation by immersing a Zn‐MOF as a template in DMF solutions of copper(II) salts. The Cu‐MOF serves as recyclable nano‐catalyst for the preparation of 5‐substituted 1H‐tetrazoles via [3 + 2] cycloaddition reaction of various nitriles and sodium azide in a green medium (PEG). The post‐synthetic metalated MOF were characterized by FT‐IR spectroscopy, powder X‐ray diffraction (PXRD), atomic absorption spectroscopy (AAS), and energy dispersive X‐ray spectroscopy (EDX) techniques. The morphology and size of the nano‐catalyst were determined by field emission scanning electron microscopy (FE‐SEM).     

Separation of Cd(II) and Ni(II) ions by supported liquid membrane using D2EHPA/M2EHPA as mobile carrier

The separation of Cd(II) and Ni(II) ions was studied in an aqueous sulphate medium using supported liquid membrane (SLM). D2EHPA/M2EHPA was used as a mobile carrier, microporous hydrophobic PTFE film was used as a solid support for the liquid membrane, and the strip phase was sulphuric acid. The effects of different parameters such as feed concentration, carrier concentration, feed phase pH, and strip phase pH on the separation factor and flux of Cd(II) and Ni(II) ions were studied. The optimum values obtained to achieve the maximum flux were 5.0 for feed pH, 40 vol. % for D2EHPA/M2EHPA concentration in the membrane phase, 0.5 for strip pH, and 0.012 mass % for feed concentration. Under these optimum conditions, the flux values of Cd(II) and Ni(II) were 15.7 × 10^?7 kg m^?2 s^?1 and 2.6 × 10^?7 kg m^?2 s^?1, respectively. The separation factors of Cd(II) over Ni(II) were studied under different experimental conditions. At a carrier concentration of 10 vol. % and feed concentration of 0.012 mass %, the maximum value of 185.1 was obtained for the separation factor of Cd(II) over Ni(II). After 24 h, the percentages of the extracted Cd(II) and Ni(II) were 83.3 % and 0.45 %, respectively.     

Computational-Based Approach for Predicting Porosity of Electrospun Nanofiber Mats Using Response Surface Methodology and Artificial Neural Network Methods

Comparative studies between response surface methodology (RSM) and artificial neural network (ANN) methods to find the effects of electrospinning parameters on the porosity of nanofiber mats is described. The four important electrospinning parameters studied included solution concentration (wt.%), applied voltage (kV), spinning distance (cm) and volume flow rate (mL/h). It was found that the applied voltage and solution concentration are the two critical parameters affecting the porosity of the nanofiber mats. The two approaches were compared for their modeling and optimization capabilities with the modeling capability of RSM showing superiority over ANN, having comparatively lower values of errors. The mean relative error for the RSM and ANN models were 1.97% and 2.62% and the root mean square errors (RMSE) were 1.50 and 1.95, respectively. The superiority of the RSM-based approach is due to its high prediction accuracy and the ability to compute the combined effects of the electrospinning factors on the porosity of the nanofiber mats.     

Molybdenum (VI)‐functionalized UiO‐66 provides an efficient heterogeneous nanocatalyst in oxidation reactions

A novel heterogeneous nanocatalyst was established by supporting molybdenum (VI) on Zr₆ nodes in the structure of the well‐known UiO‐66 metal–organic framework (MOF). The structure of the UiO‐66 before and after Mo (VI) immobilization was confirmed with XRD, DR‐FTIR and UV–vis spectroscopy, and the presence and amount of Mo (VI) was identified by X‐ray photoelectron spectroscopy and inductively coupled plasma atomic emission spectroscopy. TEM imaging confirmed the absence of Mo clusters on the MOF surface, while SEM confirmed that the appearance of the MOF has not changed upon immobilizing the Mo (VI) catalyst. BET adsorption measurements were used to confirm the porosity of the catalyst. The catalytic activity of this heterogeneous catalyst was investigated in oxidation of sulfides with H₂O₂ in acetonitrile and oxidative desulfurization of dibenzothiophene. Easy work up, convenient and steady reuse and high activity and selectivity are prominent properties of this new hybrid material.     

Third order harmonics generation in multilayer nanoshells

Third order harmonics generation has been investigated for multilayer nanoshell structure. Numerical calculations show that the nonlinear susceptibility of this structure depends on the parameters such as size and kind of structure, relaxation time and pump photon energy. The intensity and position of third order nonlinear susceptibility peaks depend on shell thicknesses; smaller thicknesses have peak susceptibility at shorter wavelength.