Understanding Liquid Phase Heterogeneous Catalysis to Develop Catalytic Processes

This project is associated with the understanding of heterogeneous catalysts for liquid phase reactions. In particular, we aim to develop a number of techniques by which to probe the reactions within the pores of the heterogeneous catalysts in order to correlate the activity-selectivity of the catalyst with the specific surface and liquid phase interactions. This research will bridge the knowledge gap between understanding the properties of liquids confined in the pores of typical heterogeneous catalysts, and their applications. This lack of understanding of the multiphase interactions underpinning the chemical efficacy of these complex systems is one of the major factors restraining the advancement of many sustainable catalytic processes which involve complex solid/liquid and solid/liquid/gas interfaces. For example, diffusion processes as well as adsorption are critically important in determining the selectivity of these multiphase reactions. However, within the pores of the catalyst in liquid phase reactions it is difficult to evaluate their relative contributions as the observed global kinetics observed are a combination of surface reaction kinetics as well as mass transport. A range of complementary NMR and neutron scattering techniques will be established from which, for example, the diffusion characteristics, pore liquid phase structure and adsorption modes will be elucidated under reaction conditions. The information from these new techniques will be combined with X-ray absorption and infra-red spectroscopy data as well as Density Functional Theory calculations and kinetic modelling in order to obtain a complete description of a gas/liquid reaction within a porous heterogeneous catalyst system under reaction conditions. In order to develop the techniques two families of exemplar selective hydrogenation reactions will be used. The hydrogenation of phenylacetylene to styrene and ethylbenzene will provide a test bed for the techniques which requires low pressures and temperatures and is a sequential reaction. Once established, higher pressure and temperature cells will be developed to enable the study of aromatic acid hydrogenation. The catalyst for this reaction can be tailored to favour a number of products including the aromatic alcohol, ring hydrogenated alcohol or toluidyl derivatives and presents a more challenging process with multiple pathways but one which is industrially very relevant. The project will be undertaken by the Queen's University of Belfast, University of Cambridge, ISIS and Johnson Matthey in close collaboration.

Using RCUK typology, we see this project as having impact in at least seven areas:

Environmental sustainability, protection & impact
Commercialisation & Exploitation
Increasing public engagement with research & related societal issues
Worldwide academic advancement
Innovative methodologies, equipment, techniques, technologies and cross-disciplinary approaches
Training highly skilled researchers
Enhancing the knowledge economy.

The beneficiaries of the research will be society as a whole, the UK economy and industry. Within the project, strong collaborations exist between Johnson Matthey, ISIS and academic members. The presence of Johnson Matthey provides a direct path for the impact to be realised through potential commercialization of the catalysts that are developed. Although the proposed research concentrates predominantly on the development of new techniques to understand heterogeneously catalysed reactions, the ultimate aim of the project is to be able to develop more efficient catalysts. The general development of catalysts which can undertake more selective transformations on a range of functionalised compounds under benign conditions will increase the scope of the molecules synthesised. In addition, a significant decrease in the environmental impact of the processes undertaken will be achieved.

Catalysis is an enabling technology for many processes with many undertaken in the liquid phase using heterogeneous catalysts. The development of new tools will provide methods by which the actual processes within the catalyst pores can be examined in detail and an understanding of the real rate determining steps can be elucidated. The information will provide data for the whole process development and allow the UK to maintain its competitive edge in the chemicals and energy sectors that are reliant on catalysis. As well as directly benefiting catalysis, the techniques will provide high quality in situ information for use in the polymer industry, sensor devices, oil exploration/oil recovery, electronics industry, environmental protection (for example in adsorption processes) and synthesis of materials (for example supported metal catalysts). These areas have wide economic impact in the UK and will benefit significantly from the ability to monitor the composition as well as the structural changes within solid materials interacting with liquids.

The research project will deliver highly skilled scientists and engineers and will provide an excellent training environment for the researchers. This will be achieved as a result of the multidisciplinary nature of the research which will be extended through collaboration to a wide range of different disciplines including chemistry, chemical engineering, mechanical engineering and physics. In addition, the researchers will benefit from the strong interaction between industry, academia and ISIS. This close cooperation will enable the staff and students in the project to become effective academics or industrialists in the future where these interactions are critical for success.

After protection of the IPR, the results of the research would be disseminated to the academic community through publications in peer-reviewed journals, presentations at major catalysis and NMR conferences and invited lectures. Of significant importance is the dissemination of the new methodologies to the wider community in particular to groups outside the catalysis community who will benefit from the new information obtained leading to wider impact. In addition, the partners will undertake public engagement to relate the research to the benefits of society. This research will form a part of the teacher's conference in QUB, for example, which enables advanced techniques and concepts to be introduced. The teachers will be shown how MRI can be used outside the health sector as well as what neutrons can probe and the concepts of liquid structure.