Development of methods for determining the intrinsic kinetics and for clarifying the mechanisms of heterogeneously catalyzed hydrogenation reactions by in situ MAS NMR under flow conditions

开发流动条件下原位 MAS NMR 确定本征动力学和阐明非均相催化氢化反应机理的方法

• 批准号: 243834932
• 负责人: Professor Dr. Michael Hunger
• 金额: --
• 依托单位: Institut für Technische Chemie (ITC)
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2013
• 资助国家: 德国
• 起止时间: 2012-12-31 至 2016-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/243834932?language=en
• 关键词: Development; methods; determining; intrinsic; kinetics

Methods of in situ MAS NMR spectroscopy under flow conditions will be developed, which can be utilized for the (i) determination of the intrinsic hydrogenation activity of metal-modified solid catalysts and for (ii) elucidating the mechanisms of these reactions. The (i) determination of the intrinsic hydrogenation activity will be performed via semibatch experiments consisting at first in the adsorption of the reactants to be hydrogenated on the activated and reduced solid catalyst and, subsequently, in the study of the hydrogenation kinetics under flowing hydrogen by in situ MAS NMR spectroscopy. The advantage of this approach is the decoupling of the time-dependence of the hydrogenation reaction from transport limitations of the reactants and reaction products as well as the time-dependent catalyst deactivation. After optimizing the experimental parameters and the reaction conditions as well as the selection and investigation of suitable reactant molecules, comparative studies of the intrinsic hydrogenation activity of different metal-modified zeolite catalysts and novel solid catalysts, such as metal-modified FSP-aluminosilicate nanoparticles (FSP: flame spray pyrolysis), in microemulsions prepared metal-nanoparticles on mesoporous supports, and metal-organic frameworks, will be performed. By this way, new findings on the effects of the nature, composition, and size of metal atoms and clusters as well as different support and host materials on the intrinsic hydrogenation activities of the above-mentioned catalyst systems are expected. Preparing the studies of the (ii) mechanisms of heterogeneously catalyzed hydrogenation reactions, experiments on the use of parahydrogen-induced polarization (PHIP) are planned. In the case of a pairwise incorporation of the two hydrogen atoms of a parahydrogen molecule into a reactant, such as by hydrogenation of olefins, the initial spin order is converted into a large nonequilibrium spin polarization (hyperpolarization). The corresponding NMR signals, which are strongly enhanced in their intensities, have characteristic antiphase shapes. Metal-modified solid catalysts with high intrinsic hydrogenation activities will be applied for hydrogenating olefins of different sizes and adsorption properties with parahydrogen, and their PHIP effect will be studied by in situ MAS NMR spectroscopy under flow conditions. Furthermore, experiments focusing on the transfer of hyperpolarization from 1H nuclei to hetero-nuclei in product molecules of hydrogenation reactions and in the local structure of adsorption sites are planned. These investigations focus on elucidating the mechanisms of heterogeneously catalyzed hydrogenation reactions, which should be, inter alia, discussed in relation to mechanisms suggested in literature.

将开发在流动条件下的原位MAS NMR光谱的方法，该方法可用于（i）确定金属改性的固体催化剂的内在氢化活性以及（ii）阐明这些反应的机制。 （i）确定固有氢化活性将通过半匹配实验进行，首先是在激活和还原的固体催化剂上吸附的反应物，并随后研究氢化动力学在原位的Mass NMR光谱中对氢化动力学进行研究。这种方法的优点是氢化反应与反应物和反应产物的转运局限性以及时间依赖性催化剂失活的时间依赖性。在优化了实验参数和反应条件以及对合适反应物分子的选择和研究之后，对不同金属修饰的沸石催化剂的内在氢化活性和新型固体催化剂的比较研究，例如金属修饰的FSP - 氧化铝层纳米酸盐（FSP：FLEME SPS：FLEME PROPERTICTICT），MICROEMITIONS MICROEMINES中的MICROEMINES中的MICROEMINES中的MICROEMINES中的MICROPORINES中的MICROEMOLINES中的类似类似的类似类似的类似类似的墨西哥蜂窝状菌株，这些型将执行和金属有机框架。通过这种方式，预计有望在上述催化剂系统的固有氢化活性上，有关金属原子和簇的性质，组成和大小的影响的新发现。准备了（II）的（II）机制的研究，计划使用催化性诱导的极化（PHIP）的实验。如果将偏二氢分子的两个氢原子成对掺入反应物中，例如通过烯烃的氢化，初始自旋顺序被转化为较大的非平衡自旋极化（高极化）。相应的NMR信号在强度上得到强烈增强，具有特征性的反相形状。具有较高内在氢化活性的金属改性固体催化剂将用于不同尺寸的氢化烯烃，并具有偏执型吸附性能，其PHIP效应将在流动条件下进行原位MAS NMR光谱研究。此外，计划着针对超极化从1H核转移到氢化反应产物分子和吸附位点的局部结构中的实验。这些研究的重点是阐明异质催化的氢化反应的机制，这些反应应与文献中建议的机制有关。

项目成果

Relationships between the Hydrogenation and Dehydrogenation Properties of Rh-, Ir-, Pd-, and Pt-Containing Zeolites Y Studied by In Situ MAS NMR Spectroscopy and Conventional Heterogeneous Catalysis

• DOI: 10.1021/acs.jpcc.5b11367
• 发表时间: 2016-02-01
• 期刊: JOURNAL OF PHYSICAL CHEMISTRY C
• 影响因子: 3.7
• 作者: Obenaus, Utz;Neher, Felix;Hunger, Michael
• 通讯作者: Hunger, Michael

Parahydrogen-Induced Hyperpolarization inside Meso- and Micropores of Pt-, Rh-, Ir-, and Pd-Containing Solid Catalysts

仲氢诱导的含 Pt、Rh、Ir 和 Pd 固体催化剂介孔和微孔内的超极化

• DOI: 10.1021/acs.jpcc.7b01899
• 发表时间: 2017
• 期刊: Journal of Physical Chemistry C
• 影响因子: 3.7
• 作者: U. Obenaus;S. Lang;R. Himmelmann;M. Hunger
• 通讯作者: M. Hunger

Separation of Anti-Phase Signals Due to Parahydrogen Induced Polarization via 2D Nutation NMR Spectroscopy.

通过 2D 章动 NMR 光谱分离仲氢诱导极化引起的反相​​位信号

• DOI: 10.1002/cphc.201601227
• 发表时间: 2017
• 期刊: Chemphyschem : a European journal of chemical physics and physical chemistry
• 作者: U. Obenaus;G. Althoff-Ospelt;S. Lang;R. Himmelmann;M. Hunger
• 通讯作者: M. Hunger