ELSEP - Elucidate and Separate - Palladium Catalysts in C-C and C-N Coupling Reactions
Lead Research Organisation:
Imperial College London
Department Name: Chemical Engineering
Abstract
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.
Publications
Adrio L
(2012)
Speciation of Pd(OAc) 2 in ligandless Suzuki-Miyaura reactions
in Catal. Sci. Technol.
Barreiro E
(2018)
Spatial, temporal and quantitative assessment of catalyst leaching in continuous flow
in Catalysis Today
Barreiro E
(2013)
Coinage Metal Catalysts for the Addition of O-H to C=C Bonds
in European Journal of Organic Chemistry
Brazier J
(2017)
Effects of Cl on the reduction of supported PdO in ethanol/water solvent mixtures
in Catalysis, Structure & Reactivity
Brazier J
(2014)
Catalysis in flow: Operando study of Pd catalyst speciation and leaching
in Catalysis Today
Brazier JB
(2017)
Solvent-dependent nuclearity, geometry and catalytic activity of [(SPhos)Pd(Ph)Cl]2.
in Dalton transactions (Cambridge, England : 2003)
Gorgojo P
(2014)
Ultrathin Polymer Films with Intrinsic Microporosity: Anomalous Solvent Permeation and High Flux Membranes
in Advanced Functional Materials
Gorgojo P
(2014)
Polyamide thin film composite membranes on cross-linked polyimide supports: Improvement of RO performance via activating solvent
in Desalination
Jimenez Solomon M
(2013)
High flux hydrophobic membranes for organic solvent nanofiltration (OSN)-Interfacial polymerization, surface modification and solvent activation
in Journal of Membrane Science
Jimenez Solomon M
(2012)
High flux membranes for organic solvent nanofiltration (OSN)-Interfacial polymerization with solvent activation
in Journal of Membrane Science
Jimenez-Solomon M
(2013)
Beneath the surface: Influence of supports on thin film composite membranes by interfacial polymerization for organic solvent nanofiltration
in Journal of Membrane Science
Newton M
(2016)
Operando XAFS of supported Pd nanoparticles in flowing ethanol/water mixtures: implications for catalysis
in Green Chemistry
Newton M
(2016)
Restructuring of supported Pd by green solvents: an operando quick EXAFS (QEXAFS) study and implications for the derivation of structure-function relationships in Pd catalysis
in Catalysis Science & Technology
Newton M
(2017)
Effect of retained chlorine in ENCATâ„¢ 30 catalysts on the development of encapsulated Pd: insights from in situ Pd K, L 3 and Cl K-edge XAS
in Catalysis, Structure & Reactivity
Nguyen BN
(2015)
Electronic structures of cyclometalated palladium complexes in the higher oxidation states.
in Dalton transactions (Cambridge, England : 2003)
Peeva L
(2013)
On the Potential of Organic Solvent Nanofiltration in Continuous Heck Coupling Reactions
in Organic Process Research & Development
Sorribas S
(2013)
High flux thin film nanocomposite membranes based on metal-organic frameworks for organic solvent nanofiltration.
in Journal of the American Chemical Society
Szekely G
(2014)
Sustainability assessment of organic solvent nanofiltration: from fabrication to application
in Green Chem.
Tebboth M
(2014)
Polymerised high internal phase emulsions for fluid separation applications
in Current Opinion in Chemical Engineering
Description | The Livingston and Hii Groups at Imperial (Chemical Engineering) have combined knowledge in the analysis of Pd species in organic reactions with innovative membranes, stable in nearly all solvents, with tuneable molecular discrimination properties. Researchers have developed new approaches to separation of Pd through filtration-adsorption with a new family of functionalised OSN membranes. |
Exploitation Route | New membrane applications within different industrial sectors. |
Sectors | Environment Manufacturing including Industrial Biotechology Pharmaceuticals and Medical Biotechnology |
Description | The team has invented a composite membrane for gas separation and/or nanofiltration of a feed stream solution comprising a solvent and dissolved solutes and showing preferential rejection of the solutes. The composite membrane comprises a separating layer with intrinsic microporosity. The separating layer is suitably formed by interfacial polymerisation on a support membrane. Suitably, at least one of the monomers used in the interfacial polymerisation reaction should possess concavity, resulting in a network polymer with interconnected nanopores and a membrane with enhanced permeability. The support membrane may be optionally impregnated with a conditioning agent and may be optionally stable in organic solvents, particularly in polar aprotic solvents. The top layer of the composite membrane is optionally capped with functional groups to change the surface chemistry. The composite membrane may be cured in the oven to enhance rejection. Finally, the composite membrane may be treated with an activating solvent prior to nanofiltration. |
First Year Of Impact | 2013 |
Sector | Chemicals,Energy,Environment,Manufacturing, including Industrial Biotechology,Pharmaceuticals and Medical Biotechnology |
Impact Types | Societal Economic |
Title | Electronic structures of cyclometalated palladium complexes in the higher oxidation states |
Description | |
Type Of Material | Database/Collection of data |
Year Produced | 2015 |
Provided To Others? | Yes |
Title | MEMBRANES FOR SEPARATION |
Description | The present invention relates to a composite membrane for gas separation and/or nanofiltration of a feed stream solution comprising a solvent and dissolved solutes and showing preferential rejection of the solutes. The composite membrane comprises a separating layer with intrinsic microporosity. The separating layer is suitably formed by interfacial polymerisation on a support membrane. Suitably, at least one of the monomers used in the interfacial polymerisation reaction should possess concavity, resulting in a network polymer with interconnected nanopores and a membrane with enhanced permeability. The support membrane may be optionally impregnated with a conditioning agent and may be optionally stable in organic solvents, particularly in polar aprotic solvents. The top layer of the composite membrane is optionally capped with functional groups to change the surface chemistry. The composite membrane may be cured in the oven to enhance rejection. |
IP Reference | US20140251897 |
Protection | Patent application published |
Year Protection Granted | |
Licensed | No |
Impact | Not known |
Description | Interview with Andrew Livingston by Nature Materials |
Form Of Engagement Activity | A press release, press conference or response to a media enquiry/interview |
Part Of Official Scheme? | No |
Geographic Reach | International |
Primary Audience | Industry/Business |
Results and Impact | Interview with Nature Materials |
Year(s) Of Engagement Activity | 2017 |