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991.
<正>An unexpected reaction of 10-bromomethyl-12-oxocalanolide A(2) with primary amine was demonstrated and studied. Consequentially,a new method for the preparation of N-substituted pyrroles starting fromγ-halo-α,β-unsaturated ketone was presented. 相似文献
992.
New approach to the chloride interferences elimination by addition of the interfering ion to the mobile phase is proposed and evaluated. Different eluents for the non-suppressed ion chromatographic analysis of fluorides in chlorides rich samples were tested and compared with eluent recommended by the column manufacturer. The limit of detection, linearity range and resistance to matrix effects caused by chlorides were the comparison criteria. The applicability of the selected eluent was demonstrated through the analysis of the edible salts and various tea samples. The employment of the proposed eluent shorten the time of the analysis since the only required preparation steps for edible salts were the dissolution and appropriate dilution of the samples. The recovery test was employed to verify the obtained results. 相似文献
993.
A new combinatorial catalyst system containing the disodium (R)-binaphtholate prepared in situ and a chiral quaternary ammonium salt was developed for enantioselective trifluoromethylation of aromatic aldehydes in up to 71% ee. A possible intermediate for the binaphtholate activation of the TMSCF3 and a catalytic cycle were proposed based on the experiments. 相似文献
994.
The piezoelectric film electro-deposition for optical fiber sensor with ZnO coating is studied. The zinc oxide plating film is made on the copper surface directly by cathodic electro-deposition in the Zn(NO3)2 single salt aqueous solution systems. The influences of main experimental conditions on the properties of ZnO thin film in the electro-deposition processes are analyzed and a stable, practical and economic technique is obtained. 相似文献
995.
Methanesulfonic acid (MSA) has been identified as one of the most important intermediate products of DMS reactions in the
atmosphere. Although considerable amounts of MSA have been found in the marine boundary layer, little is known about the interaction
of gaseous MSA with sea salt particles. To understand the fate of MSA in the atmosphere and its potential importance in atmospheric
chemistry, the heterogeneous reactions of gaseous MSA with micron-scale NaCl and sea salt particles were studied using diffuse
reflectance infrared Fourier transform spectrometry, X-ray photoelectron spectroscopy, and scanning electron microscopy. The
CH3SO3Na and CH3SO3
− were the major products of the condensed phase of the reaction of gaseous MSA with NaCl and with sea salt particles. The
steady-state uptake coefficient was determined to be (5.94±2.32)×10−7 (1 σ) for the reaction of gaseous MSA with NaCl particles and (2.23±1.25)×10−7 (1 σ) for the reaction of gaseous MSA with sea salt particles. The heterogeneous reaction of MSA with NaCl particles was
found to be first-order for MSA. The reaction mechanisms were discussed.
Supported by the National Natural Science Foundation of China (Grant No. 40490265) and the National Basic Research Priorities
Program (Grant No. 2002CB410802) 相似文献
996.
The solid-vapor reaction properties of [Zn(p-NH2C6H4SO3)2(H2O)2]
n
and alkyl monoamines were investigated. Two of the resulting complexes, [Zn(C2H5NH2)4](p-H2NC6H4 SO3)2 and [Zn(n-C3H7NH2)4](p-H2NC6H4SO3)2, grew into single crystals in situ during the solid-vapor reaction process and their structures were characterized by single-crystal structural analysis. 相似文献
997.
Guey‐Sheng Liou Yi‐Lung Yang Yuhlong Oliver Su 《Journal of polymer science. Part A, Polymer chemistry》2006,44(8):2587-2603
A series of novel triphenylamine‐containing aromatic polyamides and polyimides having a crank and twisted noncoplanar structures were synthesized in inherent viscosities of 0.14–0.64 dL/g and 0.11–0.67 dL/g, respectively. These polymers had useful levels of thermal stability associated with relatively high glass‐transition temperatures (174–311 °C). They exhibited strong UV–Vis absorption bands at around 300 nm in NMP solutions. The PL spectra of these polymers in NMP solutions (1 × 10?5 M) showed maximum peaks around 396–479 nm. The hole‐transporting and electrochromic properties were examined by electrochemical and spectroelectrochemical methods. Cyclic voltammetry (CV) of the polymer films cast onto an indium‐tin oxide (ITO)‐coated glass substrate exhibited two reversible oxidation redox couples at potentials of 0.70–1.01 V and 1.10–1.46 V, respectively, vs. Ag/AgCl in acetonitrile solution. The polymer films revealed electrochromic characteristics, with a color change from neutral pale yellowish to green and then to a blue oxidized form at applied potentials ranging from 0.00 to 1.75 V. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 2587–2603, 2006 相似文献
998.
Thermally curable naphthoxazine-functionalized polymers were synthesized by the reaction of linear (diamines) and branched (triamines) poly(propyleneoxide)s (Jeffamine series) having various molecular weights, with p-formaldehyde, and 2-naphthol. The structures of the resulting polymers were characterized by using FT-IR and 1H-NMR. In addition, curing behavior of these polymers was studied using differential scanning calorimeter (DSC). Hydrophilicity of these polymers, both in cured and non-cured states, was investigated by water contact angle measurements. The surface topographies of the polymers were also examined by atomic force microscope (AFM). 相似文献
999.
Gang Chen 《Tetrahedron letters》2006,47(3):255-259
Allyl amines and pyrazoles can be obtained by hydrazinolysis of 2-ketoaziridines. A variety of aziridines, including N-unprotected, N-substituted, as well as bicyclic enamine and aminal type, can be transformed into diversely substituted linear or cyclic products. The hydrazinolysis of homochiral aziridines proceeds without racemization. 相似文献
1000.
A catalytic, green and practical method for Friedel-Crafts hydroxyalkylation of mucohalic acid has been accomplished. Reaction of mucohalic acids with various electron-rich aromatic compounds in the presence of catalytic (1 mol % to 10 mol %) In(OTf)3 or Brönsted acid, such as H2SO4 in acetic acid provides γ-aryl γ-butenolides in moderate to excellent yield. 相似文献