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1.
Yandong Wu Wei Chen Yimin Jiang Yanzhi Xu Bo Zhou Leitao Xu Chao Xie Ming Yang Mengyi Qiu Dongdong Wang Qie Liu Prof. Qinghua Liu Prof. Shuangyin Wang Prof. Yuqin Zou 《Angewandte Chemie (International ed. in English)》2023,62(30):e202305491
Synthesis of cyclohexanone oxime via the cyclohexanone-hydroxylamine process is widespread in the caprolactam industry, which is an upstream industry for nylon-6 production. However, there are two shortcomings in this process, harsh reaction conditions and the potential danger posed by explosive hydroxylamine. In this study, we presented a direct electrosynthesis of cyclohexanone oxime using nitrogen oxides and cyclohexanone, which eliminated the usage of hydroxylamine and demonstrated a green production of caprolactam. With the Fe electrocatalysts, a production rate of 55.9 g h−1 gcat−1 can be achieved in a flow cell with almost 100 % yield of cyclohexanone oxime. The high efficiency was attributed to their ability of accumulating adsorbed hydroxylamine and cyclohexanone. This study provides a theoretical basis for electrocatalyst design for C−N coupling reactions and illuminates the tantalizing possibility to upgrade the caprolactam industry towards safety and sustainability. 相似文献
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《Journal of the Less Common Metals》1985,105(1):149-160
Reinvestigation of the Pr-Ga system by X-ray diffraction, differential thermal analysis, metallography, scanning electron microscopy and diffusion couples established that gallium has a wide solid solubility range in PrGa2 (78 at.% Ga) and that PrGa6, which forms peritectically at 466 ± 6 °C, exists. The possible existence of PrGa4 is postulated on the basis of indirect experimental evidence. 相似文献
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Commercial purity Ta-V alloys containing 0–60 at.% V were fabricated into wire at room temperature. Reductions in area of greater than 99% were possible without intermediate annealing. TaV2 was present in the 50 and 60 at.% V alloys. Recrystallization and mechanical property data are given. Alloys containing 0–40 at.% V have a low rate of work hardening and good properties at 1000°C and they do not show a ductile-to-brittle transition down to −195°C. 相似文献
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《Journal of the Less Common Metals》1979,63(2):171-179
The HfNi and ZrNi systems have been examined in the region 65 – 80 at.% Ni by microscope and X-ray analyses.In the HfNi system the following intermediate phases were observed: Hf3Ni7, Hf8Ni21, HfNi3(h. t.), HfNi3(l. t.) and Hf2Ni7. Hf3Ni7, which is formed peritectically at 1250 ± 20 °C, decomposes eutectoidally at 1016 ± 3 °C into Hf7Ni10 and HfNi3(l. t.). Hf8Ni21 is stable from 1300 ± 20 °C, where it forms peritectically, to 1175 ± 10 °C where it decomposes eutectoidally into Hf3Ni7 and HfNi3(l. t.). HfNi3(h. t.) is a high temperature phase, forming peritectically at 1350 ± 20 °C and transforming into HfNi3(l. t.) below 1200 ± 10 °C. Hf2Ni7 melts congruently. A eutectic between Hf7Ni10and Hf3Ni7 occurs at 1190 ± 10 °C.In the ZrNi system only one phase forming peritectically exists; this is Zr8Ni21, which is stable at least down to 800 °C. ZrNi3 is formed in a reaction between Zr8Ni21 and Zr2Ni7 at 920 ± 10 °C. Crystallographic data for the intermediate phases in the HfNi and ZrNi systems in the region 65–75 at.% Ni are presented. 相似文献
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Several intermetallic compounds exist in the composition range 10–22 at.% Sm(Sm2Co17, SmCo5, Sm2Co7) but their preparation as single-phase specimens is very difficult. In order to determine the enthalpies of formation of these compounds, measurements were carried out on four alloys containing respectively 12.9 at.% Sm, 16.4 at.% Sm, 17 at.% Sm and 19.8 at.% Sm, annealed in the temperature range 950–1100 °C. The compositions of the phases present in each specimen were deduced from the characterization of the measured alloys by scanning electron microscopy, electron microanalysis and X-ray diffraction.The heats of formation were deduced from solution calorimetry in molten tin. The variation of the experimental results as a function of the samarium content enabled the enthalpy of formation of SmCo5 ( − 40.8 kJ mol−1) to be determined. The same ΔHf value as determined for the phase quenched from 950 °C was measured for SmCo5 kept at room temperature after very slow cooling. This result did not confirm the eutectoid decomposition previously reported for SmCo5.The extrapolation of the measured values for the higher and lower samarium contents leads to the evaluation of the enthalpies of formation of Sm2Co17 (−152 kJ mol−1) and Sm2Co7 (−99kJ mol−1). 相似文献
6.
L. A. Klinkova V. I. Nikolaichik N. V. Barkovskii V. K. Fedotov 《Russian Journal of Inorganic Chemistry》2006,51(7):1122-1131
The phase equilibria in the region from 80 to 100 mol % BiO1.5 are studied in the BaO-BiO1.5 system in air and under an argon atmosphere using visual polythermal analysis (VPA), X-ray powder diffraction, differential thermal analysis (DTA), electron diffraction (ED), and elemental analysis in a transmission electron microscope (EA/TEM). A series of discrete layered rhombohedral phases (RPs) with the composition Ba2Bi8+n Oy, where n = 0, 1, 2, 4, 8, or 10, is discovered. The melting character is determined for these RPs: the 1: 4 phase melts congruently; the 2: 9, 1: 5, 1: 6, and 1: 8 phases melt incongruently. The crystallization fields are 10–30°C. At p o 2 = 21 kPa, the 1: 4 phase in the subsolidus region decomposes into a 4: 13 perovskite-like phase and the 2: 9 phase. The other rhombohedral phases decompose into stages to yield Bi2O3 and a neighboring RP that is richer in barium. The Ba2Bi8+n Oy oxides are stable in argon and experience a first-order phase transformation at about 560°C. 相似文献
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High-spatial energy dispersive X-ray (EDX) microanalysis has been applied in order to reveal changes of chemical composition accompanying the formation of the lamellar structure due to discontinuous precipitation reaction in Al-22at.% Zn alloy. The line-scans performed in the reaction zone have shown that the region left behind the grain boundary (GB) after its displacement from the original position is solute depleted, similar to the de-alloying case of diffusion induced grain boundary migration. This enables the allotriomorphs to be transformed into solute-rich lamellae and development of lamellar + structure, especially if the GB moves in the direction perpendicular to its original location. If the direction of movement is strongly inclined to the original location of the GB, the growth usually stops after a short period of time, mainly due to formation of the precipitation free zone (PFZ) ahead of the reaction front. The detailed EDX examination revealed that there is a sharp change in solute content at the lamella/PFZ and PFZ/matrix alloy interfaces. The solute content in the PFZ is lower than in the neighbouring lamella and it corresponds to the equilibrium state. Therefore, one can suppose that the PFZ is formed due to backward movement of the reaction front in order to consume the excess of solute atoms stored in the lamellae in comparison with the equilibrium state. As soon as the equilibrium state is attained within the PFZ, the growth of the colony is completed. 相似文献
8.
Introduction In a series of papers the authors reported the spec-troscopy results on upconversion luminescence of the double salts between the alkali metal (Rb,Cs) halide and rare earth metal trihalide (REX3).1-4 Consequently, ex-tensive syntheses of new double salts and studies on optical properties of such species have received much more attention.5-12 Although a number of these double salts have been synthesized, the formation in alkali metal halide/rare earth metal halide double salts s… 相似文献
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V. V. Klyubin K. A. Klyubina K. N. Makovetskaya 《Russian Journal of Physical Chemistry A, Focus on Chemistry》2018,92(2):295-299
The kinetics of crystalline iodine dissolution in ethanol at room temperature and 60°C is studied using the electronic absorption spectra of iodine solutions. Dissolution is shown to proceed for more than three months. It is found that the process begins with the formation of hydroiodic acid HI and is complete with the formation of I 3 ? anions. 相似文献
12.
Burton C. Anderson 《高分子科学杂志,A辑:纯化学与应用化学》2013,50(13-14):1665-1687
Before beginning the technical subject, I'd like to take a few minutes to review Professor Marve?s long association with DuPont. Professor Marvel is known simply as “Speed” at DuPont, and I will refer to him by that title of respect. Speed has been a consultant for DuPont since February 1928, a little more than 55 years. In that time, we estimate he has made 260 trips to Wilmington or other DuPont locations from Urbana and Tucson, held 19,000 individual consulting conferences, stayed 1308 nights in the DuPont hotel (= 3.58 years), and surely, established many records for a consulting relationship, both in duration and breadth. 相似文献
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《Arabian Journal of Chemistry》2023,16(3):104537
Previously, we have shown that water adjacent to many hydrophilic substances excludes colloidal and molecular solutes. It was labelled “exclusion zone” (EZ) or “fourth phase” water. A salient feature is its characteristic light absorbance at or near 270 nm. In this study, EZ water formed against three chemically distinct surfaces, Nafion, ghee, and Whatman-5 filter paper was extracted, characterized by UV–Visible absorbance spectroscopy, and solidified either by lyophilizing or evaporation in an oven. The resulting highly stable solid was dissolved in water and confirmed as EZ water by its characteristic absorbance at 270–280 nm. We used mass spectroscopy to verify the absence of ionizable contaminants that could reproduce the characteristic “signature EZ” spectra in the three liquid preparations, or in the solids formed from desiccated EZ water that had been reconstituted in deionized water. Hence, a solid form of EZ water may, indeed, exist at room temperature. 相似文献
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Withthedevelopmentofthecomputertechniques,abinitiocalculationbecomesthestrongimplementforstudyingthechemicalreactionsystemandamendssomemechanismsproposedbyexperiment.Forexample,inthephotodissociationofthegloxalat454.5nm,Parmenteretal.measuredamixtureofpro… 相似文献
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Iryna Pohrelyuk Oleh Tkachuk Roman Proskurnyak 《Central European Journal of Chemistry》2014,12(2):260-265
The corrosion properties of Ti-6Al-4V alloy with oxidized thermodiffusion nitride coatings were investigated in isotonic 0.9% solution of NaCl at temperature of 40°C. It was shown that modification of nitride coatings by oxygen leads to a deterioration of the protective properties of nitrided surface of Ti-6Al-4V alloy. The protective properties of the alloy with nitride coatings modified by oxygen are determined by the composition of formed surface oxynitride film. 相似文献
16.
Zhanping Qiao Lihong Zhuo Xin Chen Hui Wang 《Russian Journal of Inorganic Chemistry》2008,53(3):446-449
The equilibrium solubility of the quaternary system TbCl3-CdCl2-HCl(7.92 mas. %)-H2O was determined at 298K and the corresponding equilibrium diagram was constructed. The quaternary system is complicated by
the three equilibrium solid phases: CdCl2 · H2O, TbCd4Cl11 · 14H2O (4: 1 type), and TbCl3 · 6H2O, of which the new compound Cd4TbCl11 · 14H2O was found to be congruently soluble in the system. The new compound obtained was identified and characterized by the method
of X-ray diffraction and the thermal analysis methods of thermogravimetry-differential thermogravimetry (TG-DTG).
This article was submitted by the authors in English. 相似文献
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《合成通讯》2013,43(22):3843-3850
Abstract Minisci-type radical carbamoylation of 1-bromo-β-carboline (1) gives the 3-substituted product in low yield, whereas 1-acetyl-β-carboline (3a) reacts under ipso-substitution of the acetyl group. Cyanations of the N-oxides of 1 and 3a occur under clean ipso-substitution of the groups in 1-position. 1-Methyl derivatives show no tendency to react under ipso-substitution. 相似文献
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Four contemporary examples, all published in recent years, of studies of molecular electronics at electrode–electrolyte interfaces are reviewed in this opinion article. The first illustrative example involves the switching of the redox active molecular wire between redox states, with concomitant changes in molecular conductance. This example illustrates how molecular electronics at electrode–electrolyte interfaces can be used to analyse mechanisms of electron transfer, to distinguish electrolyte effects and to provide details not readily available from ensemble measurements. The second example shows that the fluctuations of molecular conductance of a redox active molecular wire can be followed as a function of electrode potential. This shows how the stochastic kinetics of individual reaction events at electrode–electrolyte interfaces can be followed. The third example demonstrates how electrochemistry can be used to control quantum interference in single molecular wires. The fourth example shows a single-molecule electrochemical transistor concept for well-defined metal cluster containing molecular wires. 相似文献
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The molecular dynamics method is used to simulate argon solutions in water and a thin water film–argon system at low temperatures. The correlation in motions of two closely spaced argon atoms is of another nature than the correlation of two neon atoms in a neon solid solution in ice II. The structure of hydrate shells of argon atoms contains five-membered rings composed of water molecules. The solubility of argon in a water film at low temperatures is noticeably higher than at room temperature. If a water film is first cooled to the glassy state and then argon atoms are added to it, then approximately as many argon atoms are absorbed on the film surface as they are present in a cooled film in equilibrium with the argon atmosphere. Argon atoms migrate from one pit to another on the rough surface of a solid water film. 相似文献