共查询到20条相似文献,搜索用时 743 毫秒
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烯基锆化合物及硒基烯基锆化合物、锡基烯基锆化合物、磺酰基烯基锆化合物、亚磺酰基烯基锆化合物、硅基烯基锆化合物等金属或杂原子取代的烯基锆化合物 ,可通过锆氢化反应高产率和高选择性地制得 .这些试剂可与各种亲电试剂反应立体选择性地合成二取代或三取代的烯烃化合物 相似文献
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碱土金属氧化物担载Fe—MnO催化剂的CO加氢反应制低碳烯烃性能 总被引:1,自引:1,他引:1
碱土金属氧化物担载Fe-MnO催化剂可大幅度提高低碳烯烃的选择性和CO转化率,添加碱金属助剂将进一步改善其催化性能;MnO是铁催化剂由合成气制烯烃的有效助剂;碱土金属氧化物担体能抑制乙烯发生歧化反应及丙烯加氢反应,而MnO助剂主要抑制乙烯加氢反应,从而有利于提高合成气制低碳烯烃的选择性。 相似文献
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一氧化碳参与的羰基化反应是有机合成中最重要的反应之一.烯烃的氢羰基化反应已经被广泛应用于药物、材料及精细化学品的工业生产中[1].例如,乙烯的甲氧羰基化反应被用于甲基丙烯酸甲酯的工业合成,然而,该领域仍有许多挑战性难题尚未得到有效解决.烯烃的氢胺羰基化反应能以原子经济性的方式合成酰胺,且已经实现该类反应的区域选择性控制,但是,如何同时控制该类反应的区域选择性和对映选择性,以简单易得的烯烃和一氧化碳为底物直接合成手性酰胺类化合物,仍是一个悬而未决的重要难题. 相似文献
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WU Jin-Gang LI Shu-BenState Key Laboratory of Oxo Synthesis Selective Oxidation Lanzhou Institute of Chemical Physics Academia Sinica Lanzhou Gansu 《天然气化学杂志》1995,(3)
The oxidative coupling of methane over Mn2O3-Na2WO4/SiO2 catalyst has been investigated in the absence of dilute gas. 16.4% of C2 yield and 80.4% of the selectivity to C2 hydrocarbons were obtained at CH4/O2 = 8.5/1.5. The effect of flow rate on the selectivity to C2 hydrocarbons and CH4 conversion was different under the reaction condition of different ratio of CH4 to oxygen. The flow rate had a more remarkable effect on the selectivity at the lower ratio of methane to oxygen. The addition of steam into the reaction gas can increase C2 yield to some extent, but that of HC1 decrease the selectivity to C2 hydrocarbons. 相似文献
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Bercaw JE Diaconescu PL Grubbs RH Kay RD Kitching S Labinger JA Li X Mehrkhodavandi P Morris GE Sunley GJ Vagner P 《The Journal of organic chemistry》2006,71(23):8907-8917
Methanol is converted to a mixture of hydrocarbons by reaction with zinc iodide at 200 degrees C with one highly branched alkane, 2,2,3-trimethylbutane (triptane), being obtained in surprisingly high selectivity. Mechanistic studies implicate a two-stage process, the first involving heterogeneously catalyzed formation of a carbon-carbon-bonded species, probably ethylene, that undergoes homogeneously catalyzed sequential cationic methylation to higher hydrocarbons. The first stage can be bypassed by addition of olefins, higher alcohols, or arenes, which act as initiators. Rationales for the particular activity of zinc iodide and for the selectivity to triptane are proposed. 相似文献
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制备系列K改性的β-Mo2C催化剂并对其CO加氢合成低碳混合醇性能进行了考察。结果表明,K改性使β-Mo2C催化剂的CO加氢选择性发生显著变化。β-Mo2C催化剂CO加氢的产物主要为C1~C4烷烃,经K改性后β-Mo2C催化剂上产物主要为C1~C5低碳醇,其中高级醇(C2+OH)选择性可达到33.78%。通过对碱金属质量分数的考察发现,当K/Mo(原子比)为0.2时,总醇选择性达到最大值,低碳醇的时空收率达到0.12 g/(mL·h-1)。β-Mo2C催化剂上醇烃产物均符合线性Anderson-Schultz-Flory(A-S-F)分布曲线,而K改性β-Mo2C催化剂上醇产物为独特的甲醇负偏离A-S-F分布。可见,K助剂的加入有效促进了低碳醇的形成,尤其是促进了C1OH到C2OH的链增长步骤。 相似文献
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自从1982年Keller首先报导了甲烷氧化偶联制乙烯、乙烷的催化反应以来,引起国内外广泛的重视,若甲烷的转化率C达35%,C_2的选择性S(C_2)达88%,乙烯/乙烷较大时,则甲烷氧化偶联催化过程可以工业化.当前国内外的工作重点是寻求甲烷转化率高,C_2选择性好的催化剂.Li和烯土复合氧化物催化剂引起人们注意,C_2的收率Y(C_2)可达24.6%,本文采用高温灼烧而成的Li-Nd-Mg复合氧化物,Y(C_2)可达31.3%. 实验部分Li-Nd-Mg复合氧化物由高温灼烧而成,实验采用小型固定床石英反应器,反应器的直 相似文献
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笼状烃金刚烷的新合成方法 总被引:4,自引:0,他引:4
笼状烃金刚烷的新合成方法米镇涛郭建维邱立勤(天津大学化工学院天津300072)关键词金刚烷,沸石,催化异构金刚烷(三环[3.3.1.1[3,7]癸烷)是一种周正对称、非常稳定的笼状烃,是由10个碳原子和16个氢原子构成的环状四面体碳氢化合物,基本骨... 相似文献
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J. K. S. Wan Y. G. Chen Y. J. Lee M. C. Depew 《Research on Chemical Intermediates》2000,26(6):599-619
Conversion of methane to higher hydrocarbon products, in particular, aromatic hydrocarbons has been achieved with good methane
conversion and selectivity to aromatic products over heterogeneous catalysts using both high power pulsed microwave and rf
energy. For example, under microwave irradiation > 85% conversion of methane and 60% selectivity to aromatics could be achieved.
Cu, Ni, Fe and Al metallic materials are highly effective catalysts for the aromatization of methane via microwave heating;
however, with a variety of supported catalysts the major products were C2 hydrocarbons and the conversion of methane was low. The use of sponge, wire and net forms of these metal catalysts was found
advantageous in effective methane conversion. The reactions are considered to be free radical in nature and to proceed through
an intermediate stage involving formation of acetylene. The influence of catalyst nature and configuration, as well as the
microwave and rf irradiation parameters on the reaction efficiency and product selectivity has been examined in both batch
and continuous flow conditions. 相似文献
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The non-oxidative dehydro-oligomerization of methane to higher molecular weight hydrocarbons such as aroma tics and C2 hydrocarbons in a low temperature range of 773-973 K with Mo/HZSM-5,Mo-Zr/HZSM-5 and Mo-W/HZSM-5 catalysts is studied.The means for enhancing the activity and stability of the Mo-containing catalysts under the reaction conditions is reported.Quite a stable methane conversion rate of over 10% with a high selectivity to the higher hydrocarbons has been obtained at a temperature of 973 K.Pure methane conversions of about 5.2% and 2.0% have been obtained at 923 and 873 K,respectively.In addition,accompanied by the C2-C3 mixture,tht- methane reaction can be initiated even at a lower temperature and the conversion rate of methane is enhanced by the presence of tne initiator of C2-C3 hydrocarbons.Compared with methane oxidative coupling to ethylene,the novel way for methane transformation is significant and reasonable for its lower reaction temperatures and high selectivity to the desired prod 相似文献
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In the reaction of methane and carbon dioxide to C2 hydrocabons under non-equilibrium plasma, methane conversion was decreased,but selectivity of C2 hydroxarbons was increased when using La2O3/γ-Al2O3 as catalyst. So the yield of C2 hydrocarbons was higher than using plasma alone. The synergism of La2O3/γ-Al2O3 and plasma gave methane conversion of 24.9% and C2 yield of 18.1%. The distribution of C2 hydrocarbons changed when Pd-La2O3/γ-Al2O3 was used as catalyst,the major C2 product was ethylene. 相似文献
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Xiu Ling ZHANG Wei Min GONG* Bin DAI Chang Hou LIU Plasma Chemistry Laboratory Dalian University of Technology Dalian Center of Analysis Dalian Institute of Light Industry Dalian 《中国化学快报》2002,(2)
The oxidative coupling of methane (OCM) to C2 hydrocarbons using carbon dioxide as oxidant is an attractive process from environmental point of view. Only a few research papers reported for it1-3. In general, the yield of C2 hydrocarbons was about 6%. This indicated that the method of catalytic activation was unfavorable to the reaction. It is necessary for us to find a new method in order to activate reaction and improve C2 hydrocarbon yield. Non-equilibrium plasma is a cold plasma in… 相似文献