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1.
In this work, a vanillin complex is immobilized onto MCM-41 and characterized by FT-IR, X-ray diffraction, scanning electron microscopy, energy dispersive spectroscopy, thermogravimetric analysis, and BET techniques. This supported Schiff base complex was found to be an efficient and recoverable catalyst for the chemoselective oxidation of sulfides into sulfoxides and thiols into their corresponding disulfides (using hydrogen peroxide as a green oxidant) and also a suitable catalyst for the preparation of 2,3-dihydroquinazolin-4(1H)-one derivatives in water at 90°C. Using this protocol, we show that a variety of disulfides, sulfoxides, and 2,3-dihydroquinazolin-4(1H)-one derivatives can be synthesized in green conditions. The catalyst can be recovered and recycled for further reactions without appreciable loss of catalytic performance. 相似文献
2.
We give necessary and sufficient conditions for an operator on a separable Hilbert space to satisfy the hypercyclicity criterion.
This paper is a part of the second author’s Doctoral thesis, written at Shiraz University under the direction of the first
author. 相似文献
3.
Abbas Shockravi Samad Bavili T Esmael Rostami Ali Yousefi Ali Dehjurian Rahim Tohidi 《Journal of inclusion phenomena and macrocyclic chemistry》2004,49(1-2):163-166
Some new dibenzosulfo, dibenzosulfoxo macrocyclic diamides are synthesized. 相似文献
4.
The black-body radiation is considered in a theory with noncommutative electromagnetic fields; that is noncommutativity is introduced in field space, rather than in real space. A direct implication of the result on cosmic microwave background map is argued. 相似文献
5.
Maryam Mirza-Aghayan Rabah Boukherroub Mahshid Rahimifard 《Journal of organometallic chemistry》2007,692(23):5113-5116
The palladium(II) chloride/triethylsilane system has been successfully applied for the selective hydrogenation of the carbon-carbon double bond of α,β-unsaturated ketones to yield the corresponding saturated carbonyl compounds. The reaction takes place under mild conditions and affords high yields. 相似文献
6.
A variety of aromatic amines are oxidized to their corresponding quinones in excellent yields by supported iodic acid under microwave irradiation and solvent free conditions. 相似文献
7.
Ganjali MR Poursaberi T Basiripour F Salavati-Niassari M Yousefi M Shamsipur M 《Fresenius' Journal of Analytical Chemistry》2001,370(8):1091-1095
A PVC membrane electrode based on a cadmium-salen (N,N'-bis-salicylidene-1,2-ethylenediamine) complex as an anion carrier is described. The electrode has an anti-Hofmeister selectivity sequence with a preference for thiocyanate at pH 1.5-11.0. It has a linear response to thiocyanate from 1.0 x 10(-6) to 1.0 x 10(-1) mol L(-1) with a slope of 59.1 +/- 0.2 mV per decade, and a detection limit of 7 x 10(-7) mol L(-1). This electrode has high selectivity for thiocyanate relative to many common organic and inorganic anions. The proposed sensor has a fast response time of approximately 15 s. It was applied to the determination of thiocyanate in a milk sample. 相似文献
8.
Hindered internal rotation about the C‐N single bonds joining the thiuram disulfide was studied by 1H NMR complete line‐shaped analysis in different dimethyl sulfoxide‐chloroform (DMSO‐CDCl3) mixtures. From the temperature dependence of methyls proton spectra, activation parameters (Ea, ΔH≠, ΔS≠, and ΔG≠) were obtained. The Arrhenius plots showed a distinct isokinetic temperature at about 35 °C at which the exchange rate is more or less independent of the solvent composition. The resulting ΔH≠ against TΔS≠ plot showed a firmly good linear correlation, indicating the existence of an enthalpy‐entropy composition in an exchange process. 相似文献
9.
Sztukowski DM Jafari M Alboudwarej H Yarranton HW 《Journal of colloid and interface science》2003,265(1):179-186
The configuration of asphaltenes on the water-oil interface was evaluated from a combination of molar mass, interfacial tension, drop size distribution, and gravimetric measurements of model emulsions consisting of asphaltenes, toluene, heptane, and water. Molar mass measurements were required because asphaltenes self-associate and the level of self-association varies with asphaltene concentration, the resin content, solvent type, and temperature. Plots of interfacial tension versus the log of asphaltene molar concentration were employed to determine the average interfacial area of asphaltene molecules on the interface. The moles of asphaltenes per area of emulsion interface were determined from the molar mass data as well as drop size distributions and gravimetric measurements of the model emulsions. The results indicate that asphaltenes form monolayers on the interface even at concentrations as high as 40 kg/m(3). As well, large aggregates with molar masses exceeding approximately 10,000 g/mol did not appear to adsorb at the interface. The area occupied by the asphaltenes on the interface was constant indicating that self-associated asphaltenes simply extend further into the continuous phase than nonassociated asphaltenes. The thickness of the monolayer ranged from 2 to 9 nm. 相似文献
10.
Mohammad Ali Zolfigol Khodabakhsh Niknam Mojtaba Bagherzadeh Arash Ghorbani‐Choghamarani Nadiya Koukabi Maryam Hajjami Eskandar Kolvari 《中国化学会会志》2007,54(5):1115-1118
Tribromoisocyanuric acid (TBCA) and Oxone®‐MX systems were used as effective oxidizing agents for the oxidation of thiols to their corresponding disulfides under mild conditions at room temperature with good to excellent yields. 相似文献