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Composite membranes based on polyvinyl chloride and acrylonitrile butadiene styrene (ABS) copolymer have been prepared and then filled with 2–8 wt % of silica nanoparticles. Membranes were fabricated by solution casting method using dimethylacetamide. The performance of prepared membranes were studied for methane and ethane at the feed pressure of 1.0, 1.5, 2.0, and 3.0 bar at 35°C. By increasing the percentage of ABS, permeability of methane and ethane increased. In addition, by adding the silica nanoparticles in the membrane, permeability of gas increased in all cases. The highest gas pair selectivity for C2H6/CH4 could be obtained from PVC/BS (20 wt %) which loaded with 8 wt % of silica nanoparticles. The results of this study suggest that high performance gas separation nanocomposite membranes can be attained by adopting a judicious combination of blending technique for polymeric membrane, optimized loading percentage, and feed operating conditions. 相似文献
145.
Masoumeh Zakeri Mohamed Mahmoud Nasef Tina Kargaran Arshad Ahmad Ebrahim Abouzari-Lotf Jahanbakhsh Asadi 《Research on Chemical Intermediates》2017,43(2):717-728
Optimization of a green approach to the synthesis of pyrano[2,3-c]pyrazoles based on the one-pot, four-component condensation via a domino Knoevenagel/Michael/cyclization sequence was investigated. This method involved the evaluation of the activity of several ionic liquids (ILs) in various solvents. This one-pot, four-component reaction revealed simplicity, higher yield and lower toxicity advantages over a corresponding three-component method. The effect of reaction parameters including the type and amount of catalyst, type of solvent, reaction temperature and time were studied with respect to yield of pyrano[2,3-c]pyrazoles. Catalyst recyclability and time-saving aspects of the reaction suggest that this method presents real alternatives over conventional reaction protocols. 相似文献
146.
Synthesis of Novel Modified Guanidines: Reaction of Dicyandiamide with Amino Acids,Amides, and Amines in Aqueous Medium 下载免费PDF全文
Ahmed M. Soliman Shaaban K. Mohamed Mahmoud. Abd El Aleem. Ali. Ali. El‐Remaily H. Abdel‐Ghany 《Journal of heterocyclic chemistry》2014,51(5):1322-1326
Reaction of dicyandiamide with series of amino acids afforded guanidinyl pyrazolones 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , respectively. Although reaction of dicyandiamide with urea, acetamide, bezamide, allantion, p‐aminobenzoic acid, sulphanilic acid, and adenine gave biguanides 20 , 21 , 22 , 23 , 24 , 25 , 26 , respectively. All compounds have been characterized on the basis of IR and 1H‐NMR. 相似文献
147.
Ahmed M. M. Soliman Mahmoud. Abd El‐Aleem. Ali. Ali. El‐Remaily Adel. A. Sultan Hossam. Abdel‐Ghany 《Journal of heterocyclic chemistry》2014,51(5):1476-1481
5‐Amino‐3‐anilino‐1H‐pyrazole‐4‐carbonitrile 1 was alkylated with various halo reagents under phase transfer conditions to give the corresponding imidazopyrazole derivatives 2a , 2b , 2c , 3 , 4 , 5 , 6 . Pyrazolo[1,5‐a] pyrimidine derivatives 11 , 12 , 13 , 14 were prepared by treating compound 1 with different dicarbonyl reagents, namely, diethymalonate, ethyl 3‐oxo‐3‐phenylpropanoate, pentane‐2,4‐dione or ethyl 3‐oxobutanoate. 相似文献
148.
Mahmoud Reza Sohrabi 《Mikrochimica acta》2014,181(3-4):435-444
A novel type of porous metal-organic framework (MOF) was obtained from thiol-modified silica nanoparticles and the copper(II) complex of trimesic acid. It is shown that this nanocomposite is well suitable for the preconcentration of Hg(II) ions. The nanocomposite was characterized by Fourier transfer infrared spectroscopy, X-ray powder diffraction, energy-dispersive X-ray diffraction and scanning electron microscopy. The effects of pH value, sorption time, elution time, the volume and concentration of eluent were investigated. Equilibrium isotherms were studied, and four models were applied to analyze the equilibrium adsorption data. The results revealed that the adsorption process obeyed the Langmuir model. The maximum monolayer capacity and the Langmuir constant are 210 mg g?1 and 0.273 L mg?1, respectively. The new MOF-based nanocomposite is shown to be an efficient and selective sorbent for Hg(II). Under the optimal conditions, the limit of detection is 20 pg mL?1 of Hg(II), and the relative standard deviation is <7.2 % (for n?=?3). The sorbent was successfully applied to the rapid extraction of Hg(II) ions from fish, sediment, and water samples. Figure
Schematic illustration of Hg(II) sorption onto SH@SiO2/MOF nanocomposite. 相似文献
149.
Mohamed M. El-Galy Farage A. Issa Osman A. Desouky Hanan M. Diab Mahmoud R. Khattab 《Journal of Radioanalytical and Nuclear Chemistry》2011,288(3):805-811
The present study aims to use the ??-spectrometry, at NMA. A radiochemical technique [1, 2] for analysis of U-isotopes was carried out for some granite samples from Gabal Gattar and El Missikat localities and also for some reference soil samples of IAEA. Several steps of sample preparation, radiochemical separation, and source preparation were performed before analysis. The concerned sample was leached by HNO3, HF and H2O2 acids after ashing. The ashed sample was spiked with uranium tracer (232U) for chemical yield and activity calculation. Then uranium was extracted from the matrix elements with trioctylphosphine oxide (TOPO) and stripped with 1 M NH4F/0.1 M HCl solution. The uranium fraction was purified by co-precipitation with LaF3 to ensure complete removal of thorium and traces of resolution degrading elements. This was followed by a final clean-up step using an anion exchange. The pure uranium fraction was electrodeposited on a stainless steel disc from HCl/oxalate solution. The obtained results from the soil reference samples indicate general similarities between the techniques of ??-spectrometers of NMA, EAEA and IAEA for analysis of U-isotopes. The U-isotopes in the granite samples of high radioactivity levels need more attempts after dilution process to be in the limit detection of ??-spectrometry. 相似文献
150.
Treatment of N,N′-methylenedipyridinium dichloride [C5H5N-CH2-NC5H5]Cl2 with MCl2 (M = Zn or Cd) in aqueous solution gives the organic-inorganic hybrid ionic compounds [C5H5N-CH2-NC5H5] · [MCl4]. Both complex salts were fully characterised by multinuclear NMR spectroscopy, elemental analysis, and their molecular structures
confirmed by powder X-ray diffraction studies. The most striking feature in both solid state structures was the presence of
the C…Cl-M short contacts between the organic [C5H5N-CH2-NC5H5] dication and inorganic [MCl4] anion, which led to different crystal packing. For [C5H5N-CH2-NC5H5]·[ZnCl4], the C…Cl-Zn interactions led to the alternating arrangement of [C5H5N-CH2-NC5H5]2+[ZnCl4]2− to form 1-D chains in the direction [010], and each individual chain had a two-fold rotational axis along the b axis, while for [C5H5N-CH2-NC5H5] · [CdCl4] the C…Cl-Cd associations gave 2-D network. In both solid state structures, the presence of Cl-ring centroid distances gave
a strong indication of some form of Cl-π interactions. 相似文献