ELSEP - Elucidate and Separate - Palladium Catalysts in C-C and C-N Coupling Reactions

ELSEP - 阐明和分离 - C-C 和 C-N 偶联反应中的钯催化剂

• 批准号: EP/G070172/1
• 负责人: Andrew Livingston
• 金额: $ 78.61万
• 依托单位: Imperial College London
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2009
• 资助国家: 英国
• 起止时间: 2009 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=EP%2FG070172%2F1
• 关键词: ELSEP; Elucidate; Separate; Palladium; Catalysts

Palladium catalysis is one of the most powerful tools in synthetic chemistry for C-C and C-N bond formation. However, even when using very high substrate-to-catalyst ratio or immobilised catalysts, metal leaching and catalyst decomposition remain significant unsolved problems. As Pd catalysis gains greater popularity in fine chemicals and pharmaceutical processes, seeking methods to reduce Pd to acceptable levels becomes a task of major priority especially for pharmaceutical applications. While it is generally accepted that, in many cases, catalytic activity is due to some form of soluble palladium (which can be obtained from both homogeneous and heterogeneous catalysts), the precise nature of the Pd species is still unknown. Conversely, catalyst deactivation and decomposition are thought to be linked to agglomeration of Pd atoms to form nanoparticles, eventually so clustered as to become inactive (Pd black ). There are currently no reliable analytical techniques for the structural characterisation of such soluble palladium species in situ. Recently, the Hii group at Imperial (Chemistry) has made an important advance in this area, by examining the conditions that lead to the formation of Pd(0) from Pd(OAc)2, conducted using a combination of mass spectrometry and beamline ID24 at the ESRF. Molecular scale separation in organic liquids using membranes (Organic Solvent Nanofiltration, OSN) is now emerging as a new area of membrane science. The Livingston group at Imperial (Chemical Engineering) is one the leading research groups in this field, and have developed new membranes, stable in nearly all solvents, with tuneable molecular discrimination properties. This proposal seeks to couple the advances made by the Hii group in the analysis of Pd species in organic reactions with the innovations in OSN membranes coming out of the Livingston group. This powerful, cross-disciplinary team of chemical engineers and chemists will seek first to understand how, and in what form, Pd reaches solution during Pd catalysed reactions. Then, we will use this knowledge to develop new approaches to separation of Pd through filtration-adsorption with a new family of functionalised OSN membranes.The project will advance using homogeneous catalysis for the Suzuki-Miyaura (C-C bond forming) and Buchwald-Hartwig (C-N bond forming) cross-coupling reactions, two of the most important Pd-catalysed reactions of industrial interest. For each of the model systems, advanced analytical techniques such as EXAFS and mass spectrometry will be applied to elucidate physical and chemical structure of Pd species in the catalytic cycles. The reactions will be monitored by mass spectrometry in close detail using a battery of techniques including ESI-MS and MALDI-TOF, ICP and HPLC to detect the species of Pd associated with various stages of the reaction. Reacting or post-reaction mixtures are expected to contain a mixture of palladium by-products which may present problems for the analysis. It is expected that these by-products will be of different molecular weight and could be separated via a series of membranes with progressively tighter molecular weight cut-offs thus providing molecular fractionation. Permeate and retentate streams from the membranes will be analysed using the above analytical techniques to determine the differences in the structure and nature of Pd species in the reacting system. In this way, molecular fractionation by membranes will be used to understand the detailed chemistry of these reactions. Further, new OSN membranes which are surface functionalised with species which capture soluble Pd species will be developed. This step will utilise the knowledge of the form of Pd that is gained from the fundamental reaction studies. Overall we seek to make advances in both understanding anc chemical engineering of C-C and C-N coupling reaction technology, an in membrane science.

钯催化是合成化学中形成C-C键和C-N键的最有力的工具之一。然而，即使当使用非常高的底物与催化剂的比率或固定化的催化剂时，金属浸出和催化剂分解仍然是显著的未解决的问题。随着Pd催化在精细化学品和制药工艺中越来越受欢迎，寻求将Pd降低到可接受水平的方法成为主要优先任务，特别是对于制药应用。虽然人们普遍认为，在许多情况下，催化活性是由于某种形式的可溶性钯（可以从均相和非均相催化剂中获得），但Pd物质的确切性质仍然未知。相反，催化剂失活和分解被认为与Pd原子聚集形成纳米颗粒有关，最终聚集成团而变得无活性（Pd黑）。目前还没有可靠的分析技术用于原位表征这种可溶性钯物质的结构。最近，Imperial（化学）的Hii小组在这一领域取得了重要进展，通过研究导致Pd（0）从Pd（0Ac）2形成的条件，使用ESRF的质谱和束线ID 24的组合进行。有机溶剂纳滤是近年来发展起来的一个新领域。帝国理工学院（化学工程）的利文斯顿小组是这一领域的领先研究小组之一，并已开发出在几乎所有溶剂中稳定的新型膜，具有可调的分子鉴别性能。该提案旨在将Hii小组在有机反应中Pd物种分析方面取得的进展与利文斯顿小组在OSN膜中的创新结合起来。这个强大的，跨学科的化学工程师和化学家团队将首先寻求了解如何，以及以什么形式，Pd在Pd催化反应过程中达到溶液。然后，我们将利用这些知识开发新的方法，通过过滤-吸附与一个新的家庭的功能化OSN membranes.The项目将推进使用Suzuki-Miyaura（C-C键形成）和Buchwald-Hartwig（C-N键形成）交叉偶联反应，两个最重要的Pd催化的工业利益的交叉偶联反应的均相催化。对于每一个模型系统，先进的分析技术，如EXAFS和质谱将被应用于阐明物理和化学结构的钯物种在催化循环。将使用一系列技术（包括ESI-MS和MALDI-TOF、ICP和HPLC）通过质谱法密切监测反应，以检测与反应各阶段相关的Pd物质。反应或反应后的混合物预计含有钯副产物的混合物，这可能会给分析带来问题。预计这些副产物将具有不同的分子量，并且可以通过一系列具有逐渐更紧密的分子量截止的膜分离，从而提供分子分馏。将使用上述分析技术分析来自膜的渗透物流和渗余物流，以确定反应系统中Pd物质的结构和性质的差异。通过这种方式，膜的分子分馏将用于理解这些反应的详细化学过程。此外，将开发用捕获可溶性Pd物种的物种表面官能化的新OSN膜。该步骤将利用从基本反应研究中获得的Pd形式的知识。总的来说，我们寻求在C-C和C-N偶联反应技术的理解和化学工程以及膜科学方面取得进展。

项目成果

Spatial, temporal and quantitative assessment of catalyst leaching in continuous flow

• DOI: 10.1016/j.cattod.2017.10.013
• 发表时间: 2018-06-15
• 期刊: CATALYSIS TODAY
• 影响因子: 5.3
• 作者: Barreiro, Elena M.;Hao, Zhimian;Hii, King Kuok (Mimi)
• 通讯作者: Hii, King Kuok (Mimi)

Ultrathin Polymer Films with Intrinsic Microporosity: Anomalous Solvent Permeation and High Flux Membranes

• DOI: 10.1002/adfm.201400400
• 发表时间: 2014-08-13
• 期刊: ADVANCED FUNCTIONAL MATERIALS
• 影响因子: 19
• 作者: Gorgojo, Patricia;Karan, Santanu;Livingston, Andrew G.
• 通讯作者: Livingston, Andrew G.

Solvent-dependent nuclearity, geometry and catalytic activity of [(SPhos)Pd(Ph)Cl] 2

[(SPhos)Pd(Ph)Cl] 2 的溶剂依赖性核性、几何形状和催化活性

• DOI: 10.1039/c7dt01019b
• 发表时间: 2017
• 期刊: Dalton Transactions
• 影响因子: 4
• 作者: Brazier J

Polyamide thin film composite membranes on cross-linked polyimide supports: Improvement of RO performance via activating solvent

• DOI: 10.1016/j.desal.2014.02.009
• 发表时间: 2014-07-01
• 期刊: DESALINATION
• 影响因子: 9.9
• 作者: Gorgojo, P.;Jimenez-Solomon, M. F.;Livingston, A. G.
• 通讯作者: Livingston, A. G.

Effects of Cl on the reduction of supported PdO in ethanol/water solvent mixtures

Cl 对乙醇/水溶剂混合物中负载型 PdO 还原的影响

• DOI: 10.1080/2055074x.2016.1267296
• 发表时间: 2017
• 期刊: Catalysis, Structure & Reactivity
• 作者: Brazier J