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1.
An efficient and water tolerant method for the synthesis ofβ-haloamines is described utilizing hydrated nickel(Ⅱ) halides (NiX 2ⅩnH 2O X = Cl,Br,I) and aziridines as starting materials.N-Tosylaziridines reacted with NiCl 2·6H 2O or NiI 2·6H 2O givingβ-chloro -orβ-iodoamines in high yields(73-99%) within a short time,but 10 mol%of n-Bu 4NBr should be added in the reactions of N-tosylaziridines with NiBr 2·3H 2O in order to obtain the high yields of correspondingβ-bromoamines.Solvent played an important role in the reactions.The proper solvent for the reaction of NiCl 2·6H 2O was DMF,while NiBr 2·3H 2O or NiI 2·6H 2O proceeded well in 1,4-dioxane. 相似文献
2.
A simple and direct method has been developed for synthesis of nitriles based on one-pot reaction of aromatic aldehydes with three different kind of reagents:CeCl 37H 2O/KI/H 2O 2,CeCl 3·7H 2O/KI/UHP and(NH 4) 2Ce(NO 3) 6/KI/H 2O 2 in aqueous ammonia. 相似文献
3.
An organic-inorganic hybrid Fe Ⅲ–Pr Ⅲ-included 2-germano-20-tungstate [Pr(H 2O) 8] 2H 2[Fe 4(H 2O) 4(pca) 4Ge 2W 20O 72]·34H 2O(Hpca=2-pyridinecarboxylic acid)(1) was hydrothermally prepared. Its polyoxoanion comprises one tetra-Fe Ⅲ incorporated [Fe 4(H 2O) 4(pca) 4Ge 2W 20O 72]... 相似文献
4.
A pure inorganic porous framework based on the tungstoferrate[FeW 12O 40] 5-,Fe(H 2O) 6H[Na 6FeW 12O 40] 2·44H 2O(1) was obtained by the conventional aqueous solution method and characterized by elemental analysis,TG,FT-IR,UV-vis spectroscopy. Single-crystal X-ray diffraction analyses reveal that compound 1 crystallizes in the space group Fm-3m,which is composed of a porous inorganic framework[Na 6FeW 12O 40] n with two kinds of pores A and B,accommodating Fe(H 2O) 6 units in pore A,which was observed rarely in the pure inorganic framework. 相似文献
5.
A mild and efficient method for the oxidative deprotection of 1,3-oxathiolanes with Fe(NO 3) 3·9H 2O and Cu(NO 3) 2·3H 2O in the absence of solvent is reported. 相似文献
6.
为了准确分析高浓度SF 6中痕量的CO及CO 2,发展了可靠的气相色谱-火焰离子化检测器(GC-FID)方法。通过双Porapak Q色谱柱结合阀切换将SF 6从待测样品中分离并排出检测系统,从而避免SF 6可能造成的在线转化柱中毒现象,同时实现CO和CO 2的完全分离;通过在线镍催化将CO和CO 2的检测转化为对CH 4的检测,极大地提高检测灵敏度。结果显示,该方法对CO和CO 2的检测互不干扰,两者都可在2~500 μL/L范围内呈现良好的线性相应,测定重复性好(RSD小于2%),准确度高。建立的GC-FID方法可直接用于SF 6高压断路器中痕量CO及CO 2的检测,为SF 6相关电气设备潜伏性故障诊断提供了研究手段。 相似文献
7.
介绍了SF 6绝缘气体分解引发的电子枪高压故障的查找和排除方法,以及Tecnai G20透射电镜日常维护的一些经验与体会。 相似文献
8.
A {Ni 7} cluster-substituted sandwich-type phosphotungstate Na 10(NH 4) 4[{(B-a-PW 9O 34)Ni 3 (OH)(H 2O) 2(HAIe)} 2Ni]·22H 2O(1) was syntliesized using the conventional aqueous solution method. Compound 1 represents the first nickel-containing sandwich-type polyoxometalate functionalized by bisphosphonate ligands.Fuither,the sandwich-type polyoxoanions aggregated via the H-bonding interactions into a two-dimensional(2D) supramolecular framework. 相似文献
9.
Well-defined two-dimensional (2D) cobalt oxalate (CoC 2O 4·2H 2O) nanosheets exhibit more excellent property than common bulk cobalt oxalate due to high specific surface areas and high-efficient transport of ion and electron. However, the delicate control of the 2D morphology of CoC 2O 4·2H 2O during their synthesis remains challenging. Herein, 2D CoC 2O 4·2H 2O nanosheets (M1), grown by straightforward che... 相似文献
10.
氢氧化钠与己二胺四甲叉膦酸(H 8L)在水溶液中反应合成了一个新型的配合物[Na 3(H 6L) 2(H 2O) 8][Na(H 2O) 6]·8H 2O(1),其结构经IR和X-射线单晶衍射表征。结果表明1属P-1空间群,晶胞参数a=7.705 9(1) , b=11.655 6(2) , c=18.119 7(3) ,α=97.247(1)°,β=94.797(1)°, γ=101.827(1)°。 1中部分钠离子通过与四膦酸配体中的氧原子配位,形成一维链状结构{[Na 3(H 6L) 2(H 2O) 8] -} ∞,该阴离子链的电荷被孤立离子团[Na(H2O) 6] +平衡。在未配位的膦酸基团、氨基、配位水分子、结晶水分子之间的氢键相互作用下,化合物堆积形成一个结构致密的三维超分子结构。 相似文献
11.
The absolute yields of gaseous oxyfluorides SOF 2, SO 2F 2, and SOF 4 from negative, point-plane corona discharges in pressurized gas mixtures of SF 6 with O 2 and H 2O enriched with 18O 2 and H 2
18O have been measured using a gas chromatograph-mass spectrometer. The predominant SF 6 oxidation mechanisms have been revealed from a determination of the relative 18O and 16O isotope content of the observed oxyfluoride by-product. The results are consistent with previously proposed production mechanisms and indicate that SOF 2 and SO 2F 2 derive oxygen predominantly from H 2O and O 2, respectively, in slow, gas-phase reactions involving SF 4, SF 3, and SF 2 that occur outside of the discharge region. The species SOF 4 derives oxygen from both H 2O and O 2 through fast reactions in the active discharge region involving free radicals or ions such as OH and O, with SF 5 and SF 4. 相似文献
12.
The reaction of the strong monophosphazene base with the weakly acidic phenol leads to the formation of a phenol–phenolate anion with a moderately strong hydrogen bond. Application of the more powerful tetraphosphazene base (Schwesinger base) renders the isolation of the corresponding salt with a free phenolate anion possible. This compound represents the first species featuring the free phenolate anion [H 5C 6-O] −. The deprotonation of phenol derivatives with tetraphosphazene bases represents a great way for the clean preparation of salts featuring free phenolate anions and in addition allows the selective syntheses of hydrogen bonded phenol-phenolate salts. This work presents a phosphazenium phenolate salt with a redox potential of −0.72 V and its capability for the selective activation of the chemically inert greenhouse gas SF 6. The performed two-electron reduction of SF 6 leads to phosphazenium pentafluorosulfanide ([SF 5] −) and fluoride salts. 相似文献
13.
Using a computer controlled version of the Ben-Naim and Baer apparatus, the solubilities of He, Ne, Ar, Kr, H 2, D 2, N 2, O 2, CH 4, C 2H 6, C 3H 8, CF 4, and SF 6 in D 2O (and the solubility of CF 4 in H 2O) were determined at four temperatures in the range 288 to 318 K and at a partial pressure of gas of 101.325 kPa. The precision of the measurements was 0.3–1.0%. The experimental data were processed using rigorous thermodynamic methods and were fitted to the Clarke-Glew-Weiss equation. Changes in the thermodynamic properties on solution were calculated from the smoothing equations. Scaled-particle theory (SPT) was used to determine the Lennard-Jones (6,12) pair potential parameters for D 2O: =0.275 nm and /k=83.4 K. Experimental mole fraction solubilities and thermodynamic functions at 298.15 K were compared with results calculated using the SPT. The thermodynamic transfer functions of gases from H 2O to D 2O were calculated. The changes induced by the solvation process on the structure of water were estimated from the Gibbs energy of transfer and the difference in the hydrogen bond energies for D 2O and H 2O. 相似文献
14.
Addition of pentafluorothio bromide, SF 5Br, to ethyl propiolate results in an 1:1 adduct, SF 5CHCBrC(O)OC 2H 5, and a small amount of a 1:2 adduct. The former is converted by reduction to the corresponding β-SF 5-acrylic ester, SF 5CHCHC(O)OC 2H 5. Treatment of SF 5CH 2CBr(CH 3)C(O)OCH 3 with base produces methyl-β-SF 5-methacrylate, SF 5CHC(CH 3)C(O)OCH 3. The preparation and characterization of these new compounds are described. 相似文献
15.
Sulfur hexafluoride (SF 6) gas has a quite high global warming potential and hence it is required that applying any substitute for SF 6 gas. Much interest in the use of a mixture of helium and SF 6 as arc quenching medium were investigated indicating a high performance of arc interruption. The calculated values of transport coefficients of mixtures of SF 6–He mixtures, at high temperatures are presented in this paper: to the knowledge of the authors, related data have not been reported in the literature. The species composition and thermodynamic properties are determined by the method of Gibbs free energy minimization, using standard thermodynamic tables. The transport properties including electron diffusion coefficients, viscosity, thermal conductivity and electrical conductivity, are evaluated by using the Chapman–Enskog method expanded up to the third-order approximation (second-order for viscosity). Particular attention is paid to the collision integral database by the use of the most accurate and recent cross-sections or interaction potentials available in the literature. The calculations, which assume local thermodynamic equilibrium, are performed in the temperature range from 300 to 30,000 K for different pressures between 0.1 and 16 atm. An evaluation of the current interruption performance by adding He into SF 6 is discussed from a microscopic point of view. The properties with regard to SF 6–He mixtures calculated here are expected to be reliable because of the improved collision integrals employed. 相似文献
17.
Reactions of both SF 5 and SF 2 with O( 3
P) and molecular oxygen have been studied at 295 K in a gas flow reactor sampled by a mass spectrometer. For reactions with O( 3
P), rate coefficients of (2.0±0.5)×10 –11 cm 3 s –1 and (10.8±2.0)×10 –11 cm 3 s –1 were obtained for SF 5 and SF 2 respectively. The rate coefficients for reactions with O 2 are orders of magnitude lower, with an estimated upper limit of 5×10 –16 cm 3 s –1 for both SF 5 and SF 2. Reaction of SF 2 with O( 3
P) leads to the production of SOF which then reacts with O( 3
P) with a rate coefficient of (7.9±2.0)×10 –11 cm 3 s –1. Both SO and SO 2 are products in the reaction sequence initiated by reaction between SF 2 and O( 3
P). Although considerable uncertainty exists for the heat of formation of SOF, it appears that SO arises only from reaction between SOF and O atoms which is also the source of SO 2. These results are discussed in terms of a reaction scheme proposed earlier to explain processes occurring during the plasma etching of Si in SF 6/O 2 plasmas. A comparison between the results obtained here and those reported earlier for reactions of both CF 3 and CF 2 with O and O 2 shows that there is a marked similarity in the free radical chemistry which occurs in SF 6/O 2 and CF 4/O 2 plasmas. 相似文献
18.
In gas-insulated equipment, partial over-thermal faults may occur due to poor contact and other reasons. The main insulation medium SF6 may decompose under over-thermal conditions and produce harmful products such as SO2 and HF, which can damage the equipment and reduce the insulation strength of the equipment. The method of decomposition component analysis can monitor the operating status of equipment without interference from machinery, noise and optics, and provide early warning or reminder of faults, but the premise is that the decomposition mechanism of SF6 must have been fully and in-depth understood. In the decomposition process of SF6, O2 has a significant effect, but the mechanism of the effect is still unclear. Based on the isotope tracing method, this paper uses 18O2 instead of ordinary O2 for overheating experiments. Through the quantitative detection of the labeled products in the product and the abundance of 18O isotope in the products, the effect of O2 on the formation of the main decomposition products was analyzed. The work makes the reaction process and mechanism of SF6 with trace oxygen under over-thermal conditions basically clear, which provides an important theoretical basis for on-line monitoring and fault diagnosis of equipment based on chemical analysis methods. 相似文献
19.
Processes which occur in microwave discharges of dilute mixtures of SF 6 and O 2 in He have been examined using a flow reactor sampled by a mass spectrometer. Two classes of experiments were performed. In the first set of experiments, mixtures containing 6×10 11 cm –3 SF 6, 6×10 16 cm –3 He, and O 2 in the range (0–3.6)×10 13 cm –3 were passed through a 20-W 2450-MHz microwave discharge. The gas mixtures arriving at a sample point downstream from the discharge were examined for SF 6, SF 4, SOF 2, SOF 4, SO 2F 2, SO 2, F, and O. In the second class of experiments, rate coefficients were measured for the reactions of SF 4 with O and O 2 and for the reaction of SF with O. The rate coefficient for the reaction of SF with O was found to be (4.2±1.5)×10 –11 cm –3 s –1. SF 4 was found to react so slowly with both oxygen atoms and oxygen molecules that only upper limits could be placed on the rate coefficients for these reactions. These values were 2×10 –14 cm 3 s –1 and 5×10 –15 cm 3 s –1 for reactions with O and O 2 respectively. The observed distribution of products from the discharged mixtures is discussed in terms of the measured rate coefficients. 相似文献
20.
The systematic preparation of partially fluorinated pentafluorosulfur alkanes containing no additional halogens is reported. Thus, the indirect addition of “HF” (via KF/formamide) to SF 5CH=CF 2, SF 5CFCF 2, and SF 5C(CF 3)CF 2 produces SF 5CH(in2)CF 3, SF 5CHFCF 3, and SF 5C(CF 3) 2H respectively. The monohydryl-pentafluorosulfur-F- alkanes react readily with S 2O 6F 2 to form the corresponding fluorosulfates by oxidative displacement of hydrogen, while the dihydryl derivative undergoes cleavage to produce F-acetyl fluoride. Efforts to convert some of the new materials to the important but unknown pentafluorosulfur “ketone,” SF 5C(O)CF 3, were unsuccessful. 相似文献
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