Metallacarboranes in catalysis. 6. Kinetics and mechanism of alkene hydrogenation and isomerization catalyzed by rhodacarborane clusters. A search for cluster catalysis
作者:Paul E. Behnken、James A. Belmont、David C. Busby、Mark S. Delaney、Roswell E. King, III、Charles W. Kreimendahl、Todd B. Marder、Joseph J. Wilczynski、M. Fredrick Hawthorne
DOI:10.1021/ja00322a042
日期:1984.5
Utilisation de rhodacarboranes complexes comme catalyseurs de l'isomerisation de l'hexene-1 et de l'hydrogenation du methyl-3 phenyl-3 butene-1
Rhodacarboranes 配合物的利用 comme catalyseurs de l'isomerisation de l'hexene-1 et de l'hydrogenation dumethyl-3 phenyl-3 butene-1
Effect of a Hydrogen Pretreatment on the Mechanism of Deuterium Addition and Exchange of Propene over Ni–Cu Alloy Catalysts
作者:Shuichi Naito、Mitsutoshi Tanimoto
DOI:10.1246/bcsj.64.1253
日期:1991.4
The effects of a hydrogen pretreatment on the activity and reaction intermediate in a C3H6–D2 reaction over a Ni–Cu alloy as well as Ni metal catalysts were investigated in detail by applying an isotope tracer technique. Ni metal and Ni-rich alloy catalysts, cooled down to the reaction temperature under a hydrogen atmosphere (D-surface), exhibited low activity compared to that of a surface evacuated
通过应用同位素示踪技术详细研究了氢预处理对 Ni-Cu 合金和 Ni 金属催化剂上 C3H6-D2 反应的活性和反应中间体的影响。与冷却前抽真空的表面(E 表面)相比,在氢气氛下(D 表面)冷却至反应温度的 Ni 金属和富 Ni 合金催化剂表现出较低的活性。然而,对于富铜合金催化剂,E 表面比 D 表面表现出较低的活性和较高的活化能。吸附氢的 TPD 光谱与活性对抽真空温度的依赖性的比较表明,强烈吸附的氢在较低温度下会延迟 Ni 和富 Ni 合金催化剂的反应。微波光谱分析表明,富铜合金催化剂的 D 和 E 表面上的反应中间体分别与 Cu 和 Ni 金属上的反应中间体相似。这一结果表明,一...
Hydroformylation of olefins in the presence of dicobalt octacarbonyl: some considerations
New data for the deuteroformylation of propene and hydroformylation of deuteropropenes are presented, together with revised data for the hydroformylation of but-1-ene-4-d3. The mechanism of formation of isomeric aldehydes is discussed, and it is concluded that several reaction paths may be followed depending on the reaction conditions and the structure of the substrate.
提供了丙烯的氘代甲酰化和氘代丙烯的加氢甲酰化的新数据,以及丁-1-烯-4- d 3的加氢甲酰化的修订数据。讨论了异构醛的形成机理,并得出结论,取决于反应条件和底物的结构,可以遵循几种反应路径。
Reaction Mechanism and Kinetics of Olefin Metathesis by Supported ReO<sub><i>x</i></sub>/Al<sub>2</sub>O<sub>3</sub> Catalysts
作者:Soe Lwin、Israel E. Wachs
DOI:10.1021/acscatal.5b02233
日期:2016.1.4
of propylene by heterogeneous supported ReOx/Al2O3 catalysts was investigated with in situ Raman spectroscopy, isotopic switch (D–C3= → H–C3=), temperature-programmed surface reaction (TPSR) spectroscopy, and steady-state kinetic studies. The in situ Raman studies showed that two distinct surface ReO4 sites are present on alumina and that the olefins preferentially interact with surface ReO4 sites anchored
用原位拉曼光谱,同位素转换(DC– 3 = →H–C 3 =),程序升温表面反应(TPSR)光谱研究了异质负载的ReO x / Al 2 O 3催化剂对丙烯的自我复分解反应。 ,以及稳态动力学研究。原位拉曼研究表明,氧化铝上存在两个不同的表面ReO 4位,并且烯烃优先与锚固在氧化铝酸性表面位的表面ReO 4位相互作用(烯烃吸附:C 4 = > C 3 = > C 2 =)。同位素开关实验表明,表面重新* = CH 3和R e * = CHCH 3是丙烯复分解过程中存在,以Re *表示活化表面雷尼亚位点。在低温(<100°C)下,决定速率的步骤是丙烯在两个相邻表面部位的吸附(速率≈[C 3 = ] [Re *] 2);在高温下(> 100°C),该速率-确定步骤在两个表面丙烯分子的重组(速率≈[C 3 = ] 2 [回复*])。在较小程度上,表面的复合重新* = CH 3和R e * = CHCH
In Situ Generation of Active Sites in Olefin Metathesis
gaining insight into the pathways limiting the number of active centers on the surface of a heterogeneous catalyst. The active site formation involves sequential steps requiring multiple catalyst functions: protonation of propene to surface Mo(VI)-isopropoxide species driven by surface Brønstedacid sites, subsequent oxidation of isopropoxide to acetone in the adsorbed state owing to the red-ox capability
我们对催化的理解深度取决于我们掌握的有关活性位点数量及其分子结构的信息。然而,在工作的多相催化剂表面上的活性中心的性质极难识别,并且通常缺少活性物质的精确量化。在分散在二氧化硅上的氧化钼上的丙烯复分解中,催化剂中只有 1.5% 的 Mo 原子被捕获以形成活性中心。在这里,我们将操作中的红外光谱与微量热法和反应性研究相结合,使用同位素标记来监测催化剂的形成。我们表明,活性 Mo(VI)-亚烷基部分是通过接枝氧化钼前体物质与底物分子本身的表面反应原位生成的,从而深入了解限制多相催化剂表面活性中心数量的途径。活性位点的形成涉及需要多种催化剂功能的连续步骤:由表面布朗斯台德酸位点驱动的丙烯质子化为表面 Mo(VI)-异丙醇物质,随后由于钼的氧化还原能力将异丙醇氧化为吸附状态的丙酮在丙酮解吸后留下裸露的 Mo(IV) 位点,并氧化加成另一个丙烯分子,最终产生活性 Mo(VI)-亚烷基物质。这种观点与