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电化学聚合过程中聚苯胺降解的研究 总被引：1，自引：0，他引：1
本文应用循环伏安法和紫外吸收光谱对苯胺电化学聚合过程中聚苯胺的降解进行了研究。结果表明，随着聚合的进行，产物聚苯胺同时发生一定程度降解。 相似文献
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In this study, a practical process for ozonization of benzyl alcohols to ketones and aldehydes in a rotating packed bed(RPB-O_3) reactor has been developed. Using 1-phenylethanol as a model reactant, the performance of RPB-O_3 process in different solvents has been compared with the commonly used stirred tank reactor(STR-O_3). Ethyl acetate was the optimum solvent for the conversion of 1-phenylenthanol to acetophenone in RPB-O_3 process, with 78% yield after 30 min. In a parallel STR-O_3 experiment, the yield of acetophenone was50%. Other experimental variables, i.e. O_3 concentration, reaction time, high-gravity factor and liquid flow rate were also optimized. The highest yield of acetophenone was obtained using O_3 concentration of 80 mg·L~(-1),reaction time of 30 min, high gravity factor of 40 and liquid flow rate of 120 L·h~(-1). Under the optimized reaction conditions, a series of structurally diverse primary and secondary alcohols was oxidized with(19%–92%) yield.The ozonization mechanism was studied by Electron Paramagnetic Resonance(EPR) spectroscopy, monitoring the radical species formed upon self-decomposition of O_3. The characteristic quadruple peak with the 1:2:2:1 intensity ratio that corresponds to hydroxyl radicals(·OH) was observed in the electron paramagnetic resonance(EPR) spectrum, indicating an indirect oxidation mechanism of alcohols via ·OH radical. 相似文献
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This paper deals with aniline oligomers produced by the oxidation of aniline with ammonium peroxydisulfate under alkaline conditions. Oligomers obtained in 1 mol L?1 ammonium hydroxide as microspheres have been analyzed. They are brown, non‐conducting, and are composed of tens of aniline constitutional units. They contain oxygen in semiquinonoid and quinonoid constitutional units or both, and sulfur in sulfonic or sulfate groups. Phenazine‐like units in the oligomers have been identified by UV‐visible spectra and the IR spectra support them. IR spectroscopic analysis of fractions insoluble and soluble in chloroform suggests that aniline oligomers are not uniform and strong hydrogen bonding occurs in their structure. Aniline oligomers will be potentially useful in applications that do not require conductivity but use the redox or salt–base transitions typical of polyaniline. Their applicability is illustrated by the ability to reduce silver cations to silver, base–salt transitions and in the carbonization to nitrogen‐containing carbons. Copyright © 2011 Society of Chemical Industry 相似文献
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Disperse dyes are poorly water-soluble and difficult to stably disperse in an aqueous medium, which greatly limits their application in dyeing synthetic fibers. Micronization can solve this problem. Herein, a facile way to prepare stable aqueous nanodispersions of disperse dye (C.I. disperse yellow 54) is presented by combining high-gravity antisolvent precipitation in a rotating packed bed (RPB) with spray drying. The as-prepared product had an average particle size of 120 nm, which could be readily redispersed in water. Compared with raw dye, the wettability and dispersibility of disperse dye nanoparticles were remarkably improved. Furthermore, the dyeing properties of the nanodispersions were obviously better than those of the commercial dye, which was micronized by ball milling. 相似文献
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《中国化学工程学报》2024,72(8):117-125
In this study,an integrated technology is proposed for the absorption and utilization of CO2 in alka-nolamine solution for the preparation of BaCO3 in a high-gravity environment.The effects of absorbent type,high-gravity factor,gas/liquid ratio,and initial BaCl2 concentration on the absorption rate and amount of CO2 and the preparation ofBaCO3 are investigated.The results reveal that the absorption rate and amount of CO2 follow the order of ethyl alkanolamine(MEA)＞diethanol amine(DEA)＞N-meth-yldiethanolamine(MDEA),and thus MEA is the most effective absorbent for CO2 absorption.The ab-sorption rate and amount of CO2 under high gravity are higher than that under normal gravity.Notably,the absorption rate at 75 min under high gravity is approximately 2 times that under normal gravity.This is because the centrifugal force resulting from the high-speed rotation of the packing can greatly increase gas-liquid mass transfer and micromixing.The particle size of BaCO3 prepared in the rotating packed bed is in the range of 57.2-89 nm,which is much smaller than that prepared in the bubbling reactor(＞100.3 nm),and it also has higher purity(99.6％)and larger specific surface area(14.119 m2.g-1).It is concluded that the high-gravity technology has the potential to increase the absorption and utilization of CO2 in alkanolamine solution for the preparation of BaCO3.This study provides new insights into carbon emissions reduction and carbon utilization. 相似文献
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The catalytic hydrogenation of nitrobenzene (NB) was studied in a three‐phase basket reactor with a commercial Pd/Al2O3 sample as catalyst. The kinetic experiments allowed a better understanding of the mechanism behind the formation of aniline (ANL) and by‐products, a topic not yet well comprehended. The effect of some operating conditions was studied and the existence of more by‐products than mentioned in the literature was stated; specifically, benzene formation was verified. Both the reaction kinetics and selectivity were found to be strongly dependent on the temperature, while the effect of total pressure is not that pronounced. Moreover, the high selectivity of the catalyst used in the present work was proved, and as such the deep hydrogenation of ANL to form by‐products only occurs in considerable extension when the NB concentration in the reaction mixture becomes negligible. 相似文献
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《Journal of the European Ceramic Society》2014,34(10):2453-2463
Different factors such as the way of incorporating the Y2O3 stabilizer, alumina addition and sintering temperature were assessed with the goal to improve the low temperature degradation (LTD) resistance of 3Y-TZP without compromising on the mechanical properties. The degradation of hydrothermally treated specimens was studied by X-ray diffraction, micro-Raman spectroscopy and scanning electron microscopy.Decreasing the sintering temperature decreased the LTD susceptibility of 3Y-TZPs but did not allow to obtain a LTD resistant 3Y-TZP with optimized mechanical properties. Alumina addition along with the use of Y2O3 stabilizer coated starting powder allowed to combine both an excellent toughness and LTD resistance, as compared to alumina-free and stabilizer co-precipitated powder based equivalents. Transmission electron microscopy revealed that the improved LTD resistance could be attributed to the segregation of Al3+ at the grain boundary and the heterogeneously distributed Y3+ stabilizer. 相似文献
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介绍了由苯胺出发，分别在水溶液中和溶剂中经盐酸化、氯、水解制得２，４，６－三氯苯胺的方法，选用了以氯苯为溶剂的合成方法，该法产品质量好，收率较高，且溶剂氯苯的损耗也小。 相似文献
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The catalytic activities of Y-, β-, and ZSM-5-zeolites for methylenedianiline (MDA) synthesis from the condensation reaction of aniline and formaldehyde have been investigated. Among β-zeolites with various Al concentrations (Si/Al ratios from 10 to 120 mol mol−1), β-zeolite with Si/Al ratio of 13.6 mol mol−1 shows the best catalytic performance in MDA synthesis. Y-zeolite exhibited lower catalytic activity than β-zeolites under the identical reaction conditions, however, exhibited the higher selectivity to 4,4′-MDA. Furthermore, it revealed that aniline/formaldehyde and catalyst/formaldehyde ratio, and reaction temperature also influenced on the MDA yield and isomers distribution. 相似文献
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Well-defined Fe3O4/MnOOH nanoparticles with 61.1 emu·g?1 in magnetization intensity and 90.53 m2·g?1 in surface area have been synthesized by a new-style of high-frequency impinging stream (HFIS) reactor. In this reactor, two streams first collided together to form nano Fe3O4 suspension, which subsequently flew through an S-shaped maln channel to generate high-frequency reversing high-gravity fields. At the same time, 24 thin liquid sheets impinged into the maln channel at the frequencies higher than 100 Hz to create nano Fe3O4/MnOOH colloids. The obtalned powders were characterized by transmission electron microscopy/energy dispersive spectrometer (TEM/EDS), X-ray diffraction (XRD), Brunner–Emmet–Teller (BET) and vibrating sample magnetometer (VSM). Experimental results indicated that low coating ratio prolonged the induction period of heterogeneous nucleation. The high-frequency impingements of 24 thin liquid sheets greatly accelerated the macro-mixing and the initial dispersion. The high-frequency reversing high-gravity fields promoted the meso-and micro-mixing. As a result, nano Fe3O4 cores were fleetly and uniformly covered by MnOOH precursor. As a continuously operated and static high-gravity reactor, the high-frequency impinging stream (HFIS) reactor is being developed to the large-scaled and low-cost production of various nanocomposites. 相似文献
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采用HSB生物菌剂,适用的微生物固定化技术和A^2-O2工艺治理苯胺、硝基苯混合废水,处理后的废水各项指标达到排放标准。由于无剩余污泥产生,不仅简化了流程,运行成本也降低。 相似文献
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2,6-二氯苯胺的合成新工艺 总被引：4，自引：0，他引：4
对苯胺的生产工艺路线进行了比较和研究,提出以苯胺和尿为起始原料,经缩合、氯磺化、氯化、分解和蒸水、水解、水蒸汽蒸馏、精制而制得2,6－二氯苯胺的新合成工艺路线,生产的产品质量符合巨化集团公司的企业标准,能满足用户的要求,2,6－DCA含量达到99．3％以上,以二苯基脲计总收率达65％以上,每吨仅原材料成本就降低2万元。 相似文献
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A series of polymer-clay nanocomposite (PCN) materials that consisted of emeraldine base of poly(o-ethoxyaniline) (PEA) and layered montmorillonite (MMT) clay were prepared by effectively dispersing the inorganic MMT clay platelets in organic PEA matrix via in situ oxidative polymerization. Organic o-ethoxyaniline monomers were first intercalated into the interlayer regions of organophilic clay hosts and were followed by a one-step oxidative polymerization. The as-synthesized PCN materials were characterized by Fourier transform infrared (FTIR) spectroscopy, wide-angle X-ray diffraction (XRD) and transmission electron microscopy (TEM).PCN materials at low clay loading up to 3 wt% in the form of coating (e.g. 0.5 wt%) on cold-rolled steel (CRS) were found to exhibit much superior corrosion inhibition effect as compared to those of the bulk PEA by performing a series of electrochemical measurements of corrosion potential, polarization resistance, corrosion current and impedance spectroscopy in 5 wt% aqueous NaCl electrolyte. Furthermore, it was found that a further increase of clay loading up to 3 wt% results in a slightly enhanced molecular barrier property of PCN materials. The molecular weights of PEA extracted from PCN materials and bulk PEA were determined by gel permeation chromatography (GPC) analysis with NMP as eluant. Effects of the material composition on the molecular barrier, thermal stability, electrical conductivity and optical properties of PEA along with a series of PCN materials, in the form of free-standing film, fine powder and solution, were also studied by molecular permeability measurements (GPA), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), four-point probe technique and UV-vis spectra. 相似文献
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《Ceramics International》2020,46(7):8497-8521
Thermal barrier coating (TBC) system is an essential technology in many fields associated to high temperatures. The main function of these TBCs is to protect the metallic parts against high temperatures over 1000 °C. However, degradation occurs both in thermal and mechanical performances during service. Thus, understanding the underlying degradation and failure mechanisms of TBCs is significant to assess and further enhance the durability and reliability of TBCs. Regarding the durability of TBCs, this paper reviews different failures mechanisms of TBCs caused by residual stresses, phase transformations, sintering, hot corrosion attack and oxidation. Subsequently, some methods are summarized to alleviate the undesirable effects of the causes, so as to extend the lifetime of TBCs. Regarding the thermal barrier performance of TBCs, the neoteric advances to resist degradation in thermal conductivity of TBCs are reviewed. In addition, some new ceramic materials with superior intrinsic properties are introduced for ultra-high temperature applications. In brief, this review correlates the microstructure and properties of TBCs for finer interpretation and degradation-resistant design on their thermal and mechanical properties, which would benefit the advanced TBCs in future engineering applications. 相似文献
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