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S. Sedighi 《Electrochimica acta》2010,55(5):1701-1708
In this study, we have examined the kinetics of the electrochemical hydrogenation of ethylene in a PEM reactor. While in itself this reaction is of little industrial interest, this reaction can be looked upon as a model reaction for many of the important hydrogenation processes including the refining of heavy oils and the hydrogenation of vegetable oils.To study the electrochemical hydrogenation of ethylene, several experimental techniques have been used including polarization measurements, measurement of the composition of the exit gases and potential step, transient measurements. The results show that the hydrogenation reaction proceeds rapidly and essentially to completion. By fitting the experimental transient data to the results from a zero-dimensional mathematical model of the process, a set of kinetic parameters for the reactions has been obtained that give generally good agreement with the experimental results. It seems probable that similar experimental techniques could be used to study the electrochemical hydrogenation of other unsaturated organic molecules of more industrial significance. 相似文献
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Xianfa Zhang Jing Liu Haiying Yu Jiawei Wang Zijia Yu Haiming Xie Rongshun Wang 《Electrochimica acta》2010,55(7):2414-6675
A simple and effective method, ethylene glycol-assisted co-precipitation method, has been employed to synthesize LiNi0.5Mn1.5O4 spinel. As a chelating agent, ethylene glycol can realize the homogenous distributions of metal ions at the atomic scale and prevent the growth of LiNi0.5Mn1.5O4 particles. XRD reveals that the prepared material is a pure-phase cubic spinel structure (Fd3m) without any impurities. SEM images show that it has an agglomerate structure with the primary particle size of less than 100 nm. Electrochemical tests demonstrate that the as-prepared LiNi0.5Mn1.5O4 possesses high capacity and excellent rate capability. At 0.1 C rate, it shows a discharge capacity of 137 mAh g−1 which is about 93.4% of the theoretical capacity (146.7 mAh g−1). At the high rate of 5 C, it can still deliver a discharge capacity of 117 mAh g−1 with excellent capacity retention rate of more than 95% after 50 cycles. These results show that the as-prepared LiNi0.5Mn1.5O4 is a promising cathode material for high power Li-ion batteries. 相似文献
95.
Very high ethylene selectivity values approaching 100% and very high ethanol conversion values approaching 85% were obtained in dehydration of ethanol over a new W-silicate-based nanocomposite catalyst having both meso and macropores and containing a W/Si atomic ratio of 0.85. Silicotungsticacid was successfully incorporated into the catalyst structure following a one-pot hydrothermal synthesis procedure. This catalyst is highly stable and does not loose activity in polar solvents and it has a sufficiently high surface area for catalytic applications. Calcination temperature of the catalyst was found to have a very significant effect on the catalyst structure and also on its catalytic performance in ethanol dehydration. Maximum selectivity of the second major reaction product diethylether was obtained as 0.7 at 200 °C, with the catalyst which was calcined at 400 °C. Very high ethylene and diethylether yield values obtained in this study at different reaction conditions are highly promising for the production of petrochemicals from ethanol. 相似文献
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Among industrial chemical processes, ethylene oxide manufacture emits the largest amount of CO2 (∼2-3 million tons/yr), as byproduct from the burning of both the ethylene (feed) and ethylene oxide. Further, the conventional silver-based catalytic process presents safety challenges due to the formation of explosive ethylene oxide/O2 mixtures in the gas phase. By judicious choice of the catalyst (methyltrioxorhenium), oxidant (H2O2) and reaction medium (methanol/water), a homogeneous liquid phase catalytic system has been demonstrated that eliminates CO2 formation while producing ethylene oxide at >90% selectivity at near-ambient temperatures. Given its high volatility, the ethylene oxide is easily recovered from the reaction phase by distillation. The vicinity of the gaseous ethylene feed to its critical temperature (9 °C) is exploited to significantly increase its solubility in the liquid reaction phase by facile compression beyond the critical pressure of ethylene (∼50 bar). Since H2O2 is stable at typical reaction temperatures (40 °C or less), potentially explosive ethylene oxide/O2 mixtures are avoided in the gas phase. In addition to the potential of arresting the carbon footprint of a large-scale industrial process, the demonstrated process concept shows how gas-expanded liquids can be generally exploited in homogeneous catalysis to enhance productivity. 相似文献
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概述了红外热成像技术应用于石化设备检测的基本原理和方法,着重阐明了在乙烯装置裂解炉热故障识别与诊断方面的应用,分析了故障成因。 相似文献
100.
闵蒋兴 《化学工业与工程技术》1999,20(1):19-23
对乙撑胺系列产品的国内外市场进行了分析,并对不同生产工艺技术进行了比较。认为应引进国外先进生产技术,优化产品结构,开拓新的应用领域 相似文献