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水煤气变换催化剂研究新进展 总被引:6,自引:0,他引:6
水煤气变换催化剂的工业化应用已有80多年的历史,在合成氨、合成甲醇、制氢和城市煤气工业中得到了广泛的应用,通常使用的催化剂有铁铬系高温变换催化剂、铜锌系低温变换催化剂和钴钼系宽温耐硫变换催化剂,80年代以前,随着多种原料路线(煤、石脑油、渣油和天然气等)制备工艺 相似文献
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铁铬系高(中)温变换催化剂研究现状 总被引:14,自引:0,他引:14
本文介绍和评述了国内外铁铬系高(中)温变换催化剂的现状和研究动态,其中包括铁铬系高温变换催化剂的应用和研究意义、变换反应的机理以及各种助剂的影响,并指出了该研究的发展趋势。 相似文献
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催化燃烧用金属整体催化反应器的制备及性能 总被引:2,自引:0,他引:2
采用浸涂方法制备了甲烷催化燃烧用金属.催化剂整体化反应器。该反应器以铁铬合金为金属载体,六铝酸盐为催化剂。讨论了制备过程中金属载体预处理、Al2O3中间层、分散剂种类等因素对催化剂附着稳定性的影响。结果表明:铁铬合金在1100℃处理5h有助于形成稳定的保护层;Al2O3中间层的存在阻碍了六铝酸盐的浸涂;六铝酸盐直接浸涂在金属载体上并在一定温度焙烧可形成附着性很好的催化剂层,使之用于催化燃烧反应获得了良好效果。 相似文献
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《分子催化》2015,(5)
我们研究了镍-铁双金属催化剂在乙酸水蒸气重整制氢反应中的催化性能.研究结果显示单金属铁催化剂对乙酸重整反应活性很低,但是对一氧化碳的中温变换反应有较好的催化性能.镍单金属催化剂对乙酸水蒸气重整制氢反应有非常好的初始催化活性,但是催化剂的长期稳定性很差.镍-铁复合催化剂的低温活性(623 K)和长期稳定性(100 h)都远好于单金属催化剂.这主要是因为铁的加入可以促进镍的分散,形成更多的表面活性位同时有助与防止镍的烧结.我们也对乙酸重整反应中的两个主要气体副产物(一氧化碳和甲烷)的反应路径进行了分析.研究发现反应温度决定一氧化碳和甲烷的反应路径.673 K是一个临界温度.低于此温度,甲烷的产生主要来自于一氧化碳和二氧化碳的甲烷化,而高于673 K,甲烷主要来自于乙酸的直接裂解.对于一氧化碳副产物而言,低于673 K其主要来自于乙酸的裂解或者不充分的水蒸气重整反应,而高于673 K产生的一氧化碳则主要来自与逆水煤气变换反应. 相似文献
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采用蔗糖为碳源, 正硅酸乙酯(TEOS)为硅源, 分别以草酸、硝酸铁、硝酸镍为催化剂, 用溶胶-凝胶法制备碳化硅前驱体, 考察了制备过程中催化剂的种类以及反应温度和时间对凝胶形成的影响. 发现以硝酸铁为催化剂最有利于凝胶的形成, 碳/硅物质的量比为4的前驱体在氩气气氛1350 ℃下加热10 h, 碳热还原反应趋于完成. 以该条件下合成的多孔碳化硅(比表面积133 m2·g-1)作为催化剂载体, 通过等量浸渍法获得Pt/SiC催化剂, 将其应用于一氧化碳氧化的模型反应中. 研究结果表明该催化剂有较好的催化活性和稳定性. 引入镍助剂的PtNi/SiC催化剂能进一步提高一氧化碳催化氧化反应的活性. 相似文献
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本文研究了镍-铁双金属催化剂在乙酸水蒸气重整制氢反应中的催化性能。研究结果显示单金属铁催化剂对乙酸重整反应活性很低,但是对一氧化碳的中温变换反应有较好的催化性能。镍单金属催化剂对乙酸水蒸气重整制氢反应有非常好的初始催化活性,但是催化剂的长期稳定性很差。镍-铁复合催化剂的低温活性(623 K)和长期稳定性(100小时)都远好于单金属催化剂。这主要是因为铁的加入可以促进镍的分散,形成更多的表面活性位同时有助与防止镍的烧结。本研究也对乙酸重整反应中的两个主要气体副产物(一氧化碳和甲烷)的反应路径进行了分析。研究发现反应温度决定一氧化碳和甲烷的反应路径。673K是一个临界温度。低于此温度,甲烷的产生主要来自于一氧化碳和二氧化碳的甲烷化,而高于673K,甲烷主要来自于乙酸的直接裂解。对于一氧化碳副产物而言,低于673K其主要来自于乙酸的裂解或者不充分的水蒸气重整反应,而高于673K产生的一氧化碳则主要来自与逆水煤气变换反应。 相似文献
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用溶胶-凝胶法以磷钼酸(MPA)的镍盐溶液水解钛酸四丁酯制备了NiPMo/TiO2催化剂.使用ICP、 XRD、 TG-DTA、 IR、 TPD-MS和微反应技术研究了催化剂的化学组成、热稳定性、化学吸附性质和催化反应性能.杂多钼酸盐与TiO2通过O2-在TiO2表面发生了键合.在623 K下,杂多阴离子仍保持原有的Keggin结构.CO2在Lewis酸位Ni(Ⅱ)和Lewis碱位Ni-O-Mo的桥氧协同作用下生成CO2卧式吸附态Ni(Ⅱ)←O-(CO)←(O--Ni).丙烯有多种吸附态在催化剂上吸附.在563 K、 1 MPa和空速1500 h-1的反应条件下,丙烯的摩尔转化率为3.2%,产物MAA选择性为95%. 相似文献
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Toward new camptothecins. Part 6: Synthesis of crucial ketones and their use in Friedländer reaction
Laurent Gavara Thomas Boisse Jean-Pierre Hénichart Adam Daïch Philippe Gautret 《Tetrahedron》2010,66(38):7544-5571
In the context of the preparation of camptothecin and luotonin A analogs, the synthesis of some key keto-precursors and their use in Friedländer condensation are described. This paper also focuses on the stability of these keto intermediates and emphasizes the major differences between indolizinones and pyrroloquinazolinones series. Noteworthy is also the report of some original structures isolated as by-products of some experiments. 相似文献
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The Langevin paramagnetic theory can’t describe the relation between magnetization of ferrofluids and applied magnetic field. The structuralization of ferrofluids, which is considered the main influence factor of the magnetization, is regarded. The part of magnetization works is deposited when the structure is forming. This action influences the magnetization of ferrofluids directly or indirectly. On the base of the “compressing” model, the Langevin function that usually describes the magnetization of ferrofluid is modified, and a well-fitted curve is obtained. An equation of the relation between the equivalent volume fraction after being “compressed” and the intensity of magnetic field is discovered, which approximately describes the process of magnetization. The relation between the approximate initial susceptibility and the volume fraction can be obtained from modified formula. 相似文献
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Rebecca J. Burton Mandy L. CrowtherNeal J. Fazakerley Shaun M. FilleryBarry M. Hayter Jason G. KettleCaroline A. McMillan Paula PerkinsPeter Robins Peter M. SmithEmma J. Williams Gail L. Wrigley 《Tetrahedron letters》2013
The highly regioselective Buchwald–Hartwig amination at C-2 of the cheap and readily accessible reagent, 2,4-dichloropyridine with a range of anilines and heterocyclic amines is described. This new methodology is robust and provides a facile access to 4-chloro-N-phenylpyridin-2-amines on 0.25 mol scale. These intermediates undergo a further Buchwald–Hartwig amination at higher temperature to enable rapid exploration of the chemical space at C-4 and to provide a library of 2,4-bisaminopyridines. 相似文献
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KMnO4-mediated oxidative CN bond cleavage of tertiary amines producing secondary amine was introduced, which was trapped by electrophiles (acyl chloride and sulfonyl chloride) to form amides and sulfonamides. The reaction could take place at mild condition, tolerating a wide range of function groups and affording products in moderate to excellent yields. 相似文献
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N. A. Nedolya 《Chemistry of Heterocyclic Compounds》2008,44(10):1165-1219
The review contains a concise historical account and information on the most significant researches undertaken by the staff
at the A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences on the Chemistry
of Heterocyclic Compounds.
Dedicated to Academician of the Russian Academy of Sciences B. A. Trofimov on his 70th jubilee.
Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1443–1502, October, 2008. 相似文献
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Regiospecific and direct imidation of the methyl C(sp3)–H bond of thioanisoles is realized under mild and metal-free conditions with N-fluorobis(benzenesulfonyl)imide as an oxidant and nitrogen source. Proposed mechanism suggests that thionium ion intermediates and a Pummerer-type reaction are involved. The imidation has advantages such as high step-economy, excellent functionality tolerance, and regiospecificity, giving structurally diverse imidation products. 相似文献
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《Tetrahedron》2014,70(21):3377-3384
The Rh(II)-catalyzed reaction of 2-carbonyl-substituted 2H-azirines with ethyl 2-cyano-2-diazoacetate or 2-diazo-3,3,3-trifluoropropionate provides an easy access to 2H-1,3-oxazines and 1H-pyrrol-3(2H)-ones. These compounds can be selectively prepared from the same starting material using temperature as the only varied parameter. The 2-azabuta-1,3-diene intermediate, a common precursor for both heterocyclic products, isomerizes into 2H-1,3-oxazine under kinetic control, while 1H-pyrrol-3(2H)-one is the sole product of the reaction at elevated temperatures. According to DFT-calculations a one-atom oxazine ring contraction involving ring-opening to a 2-azabuta-1,3-diene intermediate, followed by a 1,5- and 1,2-prototropic shift leads to the consecutive formation of imidoylketene and azomethine ylide, which then further undergo cyclization to the pyrrole derivative. 相似文献
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Different approaches for the synthesis of 1-benzyloxypyrazin-2(1H)-one derivatives from simple amino acids have been investigated. A library of 33 precursors for the preparation of N-hydroxy pyrazinones was obtained in moderate to good yields. 相似文献