Synthesis and antimicrobial evaluation of some novel dithiolane,thiophene, coumarin,and 2-pyridone derivatives

Novel 2-cyano-N-[1-(naphtha-2-yl)ethylidene] acetohydrazide 1 was utilized as key intermediate for the synthesis of some new dithiolane, thiophene, coumarin, 2-pyridone, and other related products containing a hydrazide moiety. Newly synthesized compounds were characterized by elemental analyses and spectral data (IR, ¹H NMR and mass spectra). The antimicrobial activity of the synthesized compounds was evaluated.     

Facile,eco-friendly,one-pot protocol for the synthesis of indole-imidazole derivatives catalyzed by amino acids

An efficient, convenient green approach for the synthesis of indole-based 2,4,5-trisubstituted and 1,2,4,5-tetrasubstituted imidazoles by multicomponent reaction of substituted 2-arylindole-3-carbaldehydes, benzil, substituted anilines, and ammonium acetate using catalytic amino acid (glycine) in ethanol is described. Several amino acids have also been evaluated as organic catalysts for these reactions. The structures of the compounds have been established on the basis of infrared, mass, and ¹H NMR spectral data. The mild reaction conditions, inexpensive/economical reagents, and good yield show the usefulness of this approach.     

Efficient copper-catalyzed Sonogashira coupling reactions and simulation studies

A practical copper-catalyzed I-substitutions of alkyl-2-iodobenzoates with alkynes have been developed using Cu powder as a catalyst under solvent, cocatalyst, and base-free conditions. This reaction system is new, facile, efficient, and economical that gives Sonogashira coupling products in excellent yields (up to 97%). The coupled products (A–J) were characterized by CHNS, ¹H NMR, and ¹³C NMR and are found soluble in ethyl acetate and dichloromethane. In addition, simulation studies of A–J were performed with aspulvinone dimethylallyltransferase enzyme and observe good binding affinity. The reported compounds may act as anti-cizmatics, anti-fobic in future and also have the inhibition of aspulvinone dimethylallyltransferase properties to control Alzheimer’s, Schizophrenia, etc. diseases.     

X‐ray induced degradation of surface bound azido groups during XPS analysis

Mesoporous silica SBA‐15 was synthesized and silanized with azidopropyl triethoxysilane in order to design a clickable material. Fourier transform infrared analysis permitted to prove the attachment of the azidopropylene groups to SBA‐15 resulting in the reactive and functional material N₃‐SBA‐15. X‐ray photoelectron spectroscopy was used to determine the surface composition of SBA‐15. However, we unexpectedly found that the surface bound azido groups undergo X‐ray induced decomposition during the X‐ray photoelectron spectroscopy analysis resulting in the formation of nitrenes. These are very reactive groups able to intercalate C―C and C―H bonds of the propylene chains as judged from the N1s peak shape. Possible mechanisms of intercalation are suggested. C1s and N1s peaks were recorded at different exposure time. N/C, N⁺/N and N⁺/C undergo exponential decay. N⁺/N reaches the value of zero in less than 80 min of exposure to the X‐ray source. The N⁺/C decay plot was fitted with first‐order kinetics, and the decomposition kinetic constant (k_dec) was found to equal to 516.4 s^?1. This is a fast X‐ray induced degradation which must be considered with care when examining clickable materials with surface bound alkyl azido groups. Copyright © 2016 John Wiley & Sons, Ltd.     

Extraction of uranium(VI) by tri iso-amyl phosphate (TiAP) in ionic liquids

Batch extraction of uranium(VI) from uranyl nitrate solutions using TiAP in ionic liquids ([BMIM]PF₆ and [HMIM]PF₆) is studied. Effects of acidity, TiAP concentration in ionic liquid and temperature on distribution coefficient are studied. Results show that distribution coefficient increases with an increase in acidity and reduces with an increase in the alkyl chain length of the cation of the ionic liquid. Extraction of uranium(VI) by TiAP-[HMIM]PF₆ system is found to involve two molecules of the extractant per metal ion and extraction is found to change from being exothermic to endothermic as the percentage of the extractant is increased.     

CoFe2O4纳米阵列催化剂的费托合成性能研究

通过可控的水热生长方法和钴铁碳酸根氢氧根水合物的焙烧在泡沫铁上制备了CoFe₂O₄纳米阵列催化剂。通过粉末X射线衍射,扫描电镜和电感耦合等离子体发射光谱表征了CoFe₂O₄纳米阵列的晶相,结构和组成。制备的催化剂被用于费托合成性能研究。CoFe₂O₄纳米阵列催化剂在5L/（g·h）的空速下具有69%的转化率,并且其性能优于粉体催化剂。     

A universal blown film apparatus for <Emphasis Type="Italic">in situ</Emphasis> X-ray measurements

A setup of blown film machine combined with in situ synchrotron radiation X-ray diffraction measurements and infrared temperature testing is reported to study the structure evolution of polymers during film blowing. Two homemade auto-lifters are constructed and placed under the blown machine at each end of the beamline platform which move up and down with a speed of 0.05 mm/s bearing the 200 kg weight machine. Therefore, structure development and temperature changes as a function of position on the film bubble can be obtained. The blown film machine is customized to be conveniently installed with precise servo motors and can adjust the processing parameters in a wide range. Meanwhile, the air ring has been redesigned in order to track the structure information of the film bubble immediately after the melt being extruded out from the die exit. Polyethylene (PE) is selected as a model system to verify the feasibility of the apparatus and the in situ experimental techniques. Combining structure information provided by the WAXD and SAXS and the actual temperature obtained from the infrared probe, a full roadmap of structure development during film blowing is constructed and it is helpful to explore the molecular mechanism of structure evolution behind the film blowing processing, which is expected to lead to a better understanding of the physics in polymer processing.     

A silica-supported palladium-bis(oxazoline) complex efficiently catalyzes the synthesis of cinnamic acid derivatives via Mizoroki–Heck coupling reactions

A palladium(II)-bis(oxazoline) complex supported on silica (Pd-BOX-Si) was prepared, characterized and applied as a catalyst in Mizoroki–Heck cross-coupling reactions. The bis(oxazoline) (BOX) ligand has a hydroxyl group that can be anchored to 4-benzyl chloride-functionalized silica gel, followed by the coordination of palladium(II) chloride. The catalytic activity and the recyclability of Pd-BOX-Si have been investigated in the production of cinnamic acid derivatives via Mizoroki–Heck coupling reactions of acrylates with aryl halides; The Pd-BOX-Si catalyst demonstrated excellent catalytic activity. Characterization of the recycled Pd-BOX-Si catalyst revealed its good stability under the reaction conditions employed.     

Comparison of multicomponent fuel droplet vaporization experiments in forced convection with the Sirignano model

The vaporization of multicomponent fuel droplets was studied experimentally in a heated flow and the results were compared to the model proposed by Abramzon and Sirignano. The droplet was suspended on a permanent holder which was set up in a thermal wind-tunnel. This wind-tunnel was fitted with a video recording system and an infra-red camera. The period during which the droplet was suspended on the holder before the opening of the hot air flow damper was recorded. This first sequence corresponds to the droplet vaporization in natural convection, whose initial experiment conditions, especially diameter, temperature, composition of the droplet, are well known. Then the damper was turn on, and the sequence of forced convection begun. The initial diameter of the droplet was recorded by the video system. The other initial conditions of this second sequence cannot be determined experimentally. The distribution of temperature in the droplet and the surface temperature, the mass fraction distribution in the droplet and the surface mass fraction were unknown. These unknown parameters were determined by coupling our experiment with a model using “the film concept” in natural convection. Experimental results were compared with the calculations and found satisfactory, in natural convection as well as in forced convection initiated by this method. The method was tested in the case of a fuel mixture droplets (heptane–decane) for different initial concentrations and variable durations of the sequence in natural convection.