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Leila S. Boulos Mona H. N. Arsanious El-Sayed M. A. Yakout 《Monatshefte für Chemie / Chemical Monthly》2007,41(9):979-984
The reaction of 3-amino-2-phenyl-4(3H)-quinazolinone with oxovinylidenetriphenylphosphorane afforded 5-phenylpyrazolo[1,5-c] quinazoline-2(3H)-one and triphenylphosphine oxide. On the other hand, when quinazolinone reacts with phosphorus ylides, the corresponding
phosphorane adducts were obtained. Moreover, quinazolinone reacts with trisdialkylaminophosphines to give the new (dialkylamino)oxophosphonium
dipolar products. Possible reaction mechanisms are considered and the structural assignments are based on analytical and spectroscopic
results. 相似文献
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H. S. Hassan M. F. Attallah S. M. Yakout 《Journal of Radioanalytical and Nuclear Chemistry》2010,286(1):17-26
Application study for the evaluation of sorption characteristics of sawdust as an economical sorbent material used for decontamination
of radioisotopes cesium and europium from aqueous solution has been carried out in the present work. In this respect, sawdust
(untreated and treated by HNO3) has been prepared from the commercial processing of wood for furniture production. Pore properties of the activated carbon
such as BET surface area, pore volume, pore size distribution, and pore diameter were characterized by N2 adsorption and DFT software. Radiotracer method onto sawdust from aqueous solutions was studied in a batch technique with
respect to pH, contact time, temperature. The kinetics of adsorption of Eu3+ and Cs+ have been discussed using five kinetic models namely, pseudo-first-order model, pseudo-second-order model, Elovich equation,
intraparticle diffusion model, and modified Freundlich equation that have been tested in order to analysis the experimental
data. Kinetic parameters and correlation coefficients were determined. It was shown that the second-order kinetic equation
could describe the sorption kinetics for two metal ions. The metal uptake process was found to be controlled by intraparticle
diffusion. Thermodynamic parameters, such as ΔH, ΔG and ΔS, have been calculated by using the thermodynamic equilibrium coefficient obtained at different temperatures. The obtained
results indicated that endothermic nature of sorption process for both 152+154Eu and 134Cs onto sawdust. 相似文献
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Mostafa M. Hamed S. M. Yakout H. S. Hassan 《Journal of Radioanalytical and Nuclear Chemistry》2013,295(1):697-708
Radioactive waste contains nitrate and nitrite as well as radioactive fission products. Nitrate and nitrite anions are two of the major components of nuclear waste streams and contribute to environmental release hazards. The removal of nitrate and nitrite is a necessary step for the further treatment low-level radioactive wastes. The focus of the research is to evaluate the adsorption potential of solid phase derived from rice straw for nitrate and nitrite anions in single- and binary-component systems due to the fact that the rice straw is a very abundant and by-product material. The removal was accomplished under the optimize conditions of temperature, concentration, pH, contact time and quantity of adsorbent as these parameters are some of the main factors influencing the uptake of two solutes at the solid–solution interface. Batch-mode kinetic and equilibrium studies have been carried out. The experimental data was analyzed using equilibrium isotherm and kinetic models. The thermodynamic parameters (?G°, ?H°, and ?S°) were also determined using the equilibrium constant value obtained at different temperatures. Results show that this adsorbent is effective and much better or even superior than many sorbents for removal of nitrate and nitrite. The prepared sorbent as solid-phase extractant was successfully applied for the extraction of nitrate from actual water samples. 相似文献
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Syntheses of the title ring systems are described starting with benzothiazol‐2‐ylacetohydrazide (1). Thus, 1 was reacted with carbon disulfide to afford the 2‐methyl heteroaryl derivative 2, which on reaction with hydrazine hydrate yielded the corresponding triazole compound 3. Also, 1 can undergo a reaction with an isothiocyanate to give the N‐thiocarbonyl adduct 4 that can then be cyclized to produce a 2‐methyl heteroaryl analog 5 or 6. Compounds 8 or 9 could be obtained by the reaction of 1 with an aryl aldehyde followed by malononitrile or via its self‐cyclization, respectively. © 1999 John Wiley & Sons, Inc. Heteroatom Chem 10: 177–182, 1999 相似文献
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Yakout El-Sayed M. A. Salam Hayam A. Abd El Nawwar Galal A. M. 《Russian Journal of Organic Chemistry》2020,56(12):2212-2221
Russian Journal of Organic Chemistry - Difficultly accessible pyrimidine, thiazolopyrimidine, triazolopyrimidine, and thiazinopyrimidine derivatives containing an oleyl residue were synthesized via... 相似文献
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Simple Zeros of the Riemann Zeta-Function 总被引:1,自引:0,他引:1
Assuming the Riemann Hypothesis, Montgomery showed by meansof his pair correlation method that at least two-thirds of thezeros of Riemann's zeta-function are simple. Later he and Taylorimproved this to 67.25 percent and, more recently, Cheer andGoldston increased the percentage to 67.2753. Here we proveby a new method that if the Riemann and Generalized LindelöofHypotheses hold, then at least 70.3704 percent of the zerosare simple and at least 84.5679 percent are distinct. Our methoduses mean value estimates for various functions defined by Dirichletseries sampled at the zeros of the Riemann zeta-function. 1991Mathematics Subject Classification: 11M26. 相似文献
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