Initial Exemplary Projects
Project 1: Activation and Reaction of sp3 Centres.
The project involves a collaboration of academics that are internationally recognised for their work in chemo- and bio- catalytic hydrogen transfer reactions and mechanism, together with representatives of key Pharma, Agrochem and Fine Chemical end-user companies. There are links we wish to exploit with other sub-projects: support from Catalyst Design in modelling ligand/metal/substrate/product interactions and catalytic cycles; other projects within Chemical Transformations such as Biocatalysis for High Value Transformations and Catalysis within Confined Environments (cf. our use of immobilised and encapsulated catalysts).1 There is a link with Energy Catalysis through our transformations involving low energy redox reactions for low energy processing; the catalysts will generate hydrogen from formic acid and C1-C3 alcohols.2 The project also has synergies with Environmental Catalysis, indeed the collaborating companies demand this, for example: improved atom efficiency of catalytic hydrogen transfer over traditional reduction and oxidation reagents (eg NaBH4, Swern); the catalysts work in sustainable solvents and would be expected to do so here;3 the methodology we develop should be applicable to renewable starting materials to enable green chemistry methods for making heterocycles (eg use of glycols, hydroxy and amino acids). A key aspect of this project is to develop industrially useful methods which necessitate efficient catalytic processes
Project 2: Selective Synthesis Gas Conversion.
The project is in the ‘Chemical Transformations’ theme since our initial focus will be on the fundamental chemistry which underpins the conversion of synthesis gas. However, there are strong links to all of the other themes – we are basically trying to achieve homogeneous Fischer-Tropsch, so the link to Energy is clear (also as downstream technology for the reforming exemplar project). The production of CO/H2 via gasification of (waste) biomass is linked to Environmental catalysis. The ‘Catalyst Design’ theme is likely to underpin every project but this project specifically tries to build bridges between homogeneous and heterogeneous catalysis, as is clear from the project team. There are also potential links to projects within the theme – cooperative effects are a common thread in a number of projects (e.g. metal-free catalysis), and the exchange of expertise and material can be envisaged. Recruitment Dr Giulio Bianchini (Bristol) Update Building on the very brief and general outline of this project in the UK Catalysis Hub, we have identified three initial areas to pursue in parallel. These (hopefully) balance a catalyst screening approach with a more fundamental catalyst design-driven approach. The Project will focus on i) CO homologation via reductive hydroformylation/dehydration, ii) Studies concerning the development of metal-containing or metal-only Lewis Pairs and iii) studies on how substitution of main group Lewis acid with an electrophilic transition metal centre was successful to boost the chemistry in a catalytic fashion
Project 3: New Catalysts and Processes for Oxygenated Polymers.
This collaboration brings together expertise in catalysis spanning homogeneous and heterogeneous catalysis, reactor engineering and process engineering. Thus, it addresses many of the fundamental aspects of catalysis. The findings from this project would also be highly complementary to, and could benefit and feed into, the project in the Environmental sub-theme (Autonomous Damage Repair). We have discussed a collaboration with projects in the Catalyst Design sub-theme whereby completely new bio-catalysts and heterogeneous catalysts could be trialed in these polymerizations. There are also overlaps/complementarity with projects in the Energy theme (auto-reforming). There is an interesting processing link to the oxidation catalysts, developed by Hutchings et al (Cardiff), as the monomer used (epoxide) could, in future, be produced using clean oxidation catalysis, which would substantially further improve the sustainability of the process. There are clear links to the facilities at Harwell (RAL), including using EXAFS to analyse catalyst structures in situ, in solvents and at temperatures 25-150 °C, and XRD, particularly under high gas pressures
Project 4: Catalysis in Confined Environments – Homogeneous Organometallic Chemistry in the Solid–State
Homogeneous organometallic transition metal catalysts use carefully tailored organic ligands to control the function of a metal centre (i.e., reactivity, selectivity, overall rate, decomposition pathways). They are well characterised by solution spectroscopic methods and their mechanisms can be studied in detail both experimentally and computationally. By contrast, heterogeneous catalysts are typically compositionally simple solids that allow easy separation of the substrates but also provide the potential for selectivity in catalysis through spatial control in cavities in the material (e.g. zeolites). However the limitations of experimental techniques and computational methods make it difficult to define and probe the catalytic site, which in turn means that options for tuning activity and selectivity of heterogeneous catalysts based on mechanistic understanding are limited. We propose a new set of materials which combine the benefits of single–site homogeneous species with the benefits of heterogeneous materials, by the synthesis of well–defined but, importantly, highly reactive low-coordinate organometallic species protected by the confined molecular environments of platform materials such as MOFs and polymer composites. It is an approach that takes the fields of both heterogeneous catalysis and homogeneous catalysis in a new and exciting direction. We will demonstrate the ambition of our methodology by applying and developing these systems in fundamentally challenging chemical transformations that also have real-world applications. The upgrading of alkanes (C–H activation followed by C–C bond formation) of abundant chemical feedstocks (primarily shale gas: methane and ethane) to higher value alkanes is one area that we will initially target. Such technology requires the development of suitably highly–reactive transition metal centres that also offer control over product distributions, confined environment platform technologies that incorporate these active centres (i.e. MOFs), mechanism (kinetics) and gas/solid reactivity (membranes). The project, will develop a program of innovation and development in the Catalysts for Chemical Transformations theme, and will have particular synergy with the sub-themes of “C–X activation” and “selective syn gas conversion” . It will also have significant bearing on other themes, in particular: Energy (production of energy–dense materials from abundant resources, e.g., reforming technologies) and Catalyst design. In this last theme the “Hybrid and hierarchical solids” and “Nanoconfinement” programs have close synergy with ours, in addition to use of inoperando methods based at Harwell.
Project 5: Transition Metal-Free Catalysis
The collaboration we propose will impact on other key areas supported by the Hub within the ‘Chemical Transformations’ theme; there is the potential for profitable overlap with ‘Catalytic Process Chemistry and C-X Activation’, and we envisage synergy with ‘Biocatalysis’ through the development of complementary high-value transformations. Our focus on catalyst efficiency and transition-metal free reactions also makes us natural partners for researchers within the ‘Environmental Catalysis’ theme. Thus, the development of controlled C-H activation chemistry by carbenoid systems (based on our exciting preliminary results in this area), for example, offers overlap with a number of projects within this theme. Key collaborative interactions within the Harwell based Hub itself are outlined below.
Project 6: Biocatalysis for High Value Transformations that Chemical Catalysis Struggles To Perform
This project will have huge breadth as a function of its use of exploitation and design of biological catalysis for application to unique transformations. It will encompass use of natural and unnatural moieties and so bridge the gap between homo and bio.