Laser-induced Photochemistry in Continuous Flow Reactors

Photochemistry is an area of research behind some of the most interesting advances in chemistry over the last century. This approach to chemistry enables the highly selective activation of molecules which can then be driven to react and undergo specific chemical syntheses. Photo-driven chemical reactions are also the basis upon which plants can harness the suns energy via photosynthesis. Furthermore, selective solar light absorption in semiconductors can allow a wide range of often highly unselective photocatalytic batch chemistries to be conducted such as oxidation and reduction reactions. Despite our knowledge of photochemistry, the subject has failed to have a significant impact on the fine chemical and manufacturing industries. In part, this is related to the difficulty in tuning/stopping photochemical reactions so that they do not give unwanted side reactions and also the difficulties associated with scaling-up laboratory photochemical reactions into industrial scale processes.

In this study, we will investigate routes for utilising tuneable photochemistry in the high value manufacture of fine chemicals and nanomaterials, providing compelling evidence of scalability towards industrial scale processes. Furthermore, we will harness special properties of light to achieve specific goals, for example by using the polarisation of light to add product specificity. All reactions will be conducted in a continuous flow reaction environment which will allow us to tune path lengths and absorption cross-sections for incident lasers, residence times, temperatures, pressures, turbulence of mixing, concentrations etc. Furthermore, as an advanced stage we will be able to use the apparatus for carrying out reactions using supercritical carbon dioxide (high pressure and moderate temperature) which is a clean solvent that will allow substantially higher miscibility's with reactive gases such as hydrogen.

The unique combination of the targeted use of light to selectively activate either a solvent or specific molecules within a continuous flow process (which has the potential to be highly scalable from the outset) has never been demonstrated before and encompasses sustainable chemistry principles.

Within the timescale of this proposal we will demonstrate proof-of-concept light-directed manufacture of fine organic complexes, including chiral molecules (molecules with a built-in 'handedness'), and surface functionalised inorganic nanomaterials, required to translate our concept to industry. We have a balanced team that includes expertise in organic chemistry and excited state light-mater interactions, inorganic synthesis and chemical engineering. In particular, this includes the recent first demonstration of supercritical continuous flow processing on a pilot-scale plant (kg/hour) which, with recent advances in chiral photochemistry, makes our proposal of exceptional timeliness.

The impact of our work will be highly significant to both industry and academia. A recent Government Department for Business, Innovation & Skills (BIS) review reported that 'The UK Chemicals sector is the seventh largest producer globally with annual sales of around £56bn, representing 12% of all UK manufacturing'.[1] The aim is to grow this sector and enable it to continue to compete internationally. To do this the report states that innovation and knowledge transfer of new technologies is required along with access to skills and training. This project directly addresses these needs. Specifically by establishing the proof-of-concept within the UK and through engagement with UK-based industry we will provide a platform to enable them to continue to compete internationally.

[1] Department for Business, Innovation and Skills report 'Growth Review Framework for Advanced Manufacturing' December 2010. URN 10/1297.

Who will benefit from the research?
The work we propose to undertake has already been identified through the audition process as being well-aligned with the 'manufacturing with light' scope and having 'excellent potential to impact manufacturing'. Specifically, fine chemical synthesis and nanomaterial manufacturing industries will directly benefit from our work. This would then have a subsequent impact on the wide range of dependent industries which utilise the fine chemicals and nanomaterial products produced, including those developing new pharmaceutical products, agrochemicals, and energy storage materials, and catalysts etc.

Such is the significance of the UK chemical manufacturing industry (£56bn, representing 12% of all UK manufacturing) our impact on this will benefit a wide range of stakeholders and end users including academia, wider industry, funders of research and policy makers, government, healthcare institutions and professionals (if new drug discovery synthetic pathways result), education, the 'third sector' and the wider public, and the UK over varying timescales from immediate to the longer term.

How will they benefit from this research?
Having initiated and been involved in defining the challenges we are addressing, the funding bodies and stakeholders that they represent will benefit from the proposed research. In particular, the outcome of our research will inform and provide direct support for future prioritisation of research areas and programmes relating to these challenges. As we develop new materials and technologies, other funders of research in different disciplines will also benefit as the outcomes are translated into applications elsewhere (e.g. drug development using asymmetric synthesis).

Those developing future technologies and undertaking research and development in collaboration with industry will directly benefit from this project. Through our interactions with industry and the potential commercialisation of the outcomes, there will be a wider benefit to the UK. Following EPSRC guidance (online) we have not provided letters of support from companies as, at this early proof of concept stage, they are not providing any direct support. Nonetheless, the companies have a watching brief and therefore after protection of any arising IP, we will engage more closely with industry, ensuring that during the latter part of the project, we will have clearly developed routes to translate the outcomes towards manufacturing industry. At the heart of our research project is an aim to ensure that the processes and materials we develop, are suitable for speedy commercial development because issues of scalability and sustainability because the outset.

The area of work we are proposing to undertake represents an example where the fields of chemistry, physics and chemical process engineering overlap in a truly multidisciplinary way. It is therefore ideally suited for providing the basis of a series of learning resources in which the importance of multidisciplinary work may be introduced to students or the public and their interactions explained. This can be applied from early school levels right through to undergraduate, as the complexity is slowly revealed. As part of our impact activities, we will therefore design and make available learning resources which will be freely available for use by students and teachers.

The UK will benefit from the research undertaken, not only through the above contributions to policy, industry, education etc., but in being able to continue to act as a leader in the area of chemical manufacturing and in particular in high value products. This will translate into the wider benefits of increased competitiveness in research and development, which itself will attract further investment in this area and further talent to the UK.