Enabling industrial deployment of deep eutectic solvents through manufacturing tools

Solvents are ubiquitous in chemistry, used to bring species together for reactions, for separations and for processing but most chemical synthesis makes use of volatile organic compounds (VOCs). VOCs are toxic, volatile, flammable and are largely passive spectators to the reactions carried out within them yet are central to all industrial production of chemical species from therapeutics to catalyst particles. Recently, however, a family of novel solvents, deep eutectic solvents (DES) have been demonstrated, by one of our team, to allow water-sensitive synthetic reactions to be safely done on the benchtop and also to play an active role in directing reactions and structuring nanomaterials. This recently developed class of solvents therefore have enormous potential to replace VOCs with safer, greener liquids which, in addition, have intriguing properties, currently not understood, that allow them to defy existing synthetic practice. Yet DES bring their own challenges to transitioning them into manufacturing practice, requiring development of a new manufacturing platform to enable their rapid deployment in industrial processes, as well as requiring an improved understanding of how these solvents facilitate syntheses.

DES are room temperature liquids consisting of mixtures of a salt and hydrogen-bonding neutral molecules. Cheap, non-toxic, biodegradable, sourced from biomass, they are highly tuneable for specific applications. Yet, surprisingly little is understood about how DES structures and interactions facilitate and direct syntheses. This project aims to link a greater understanding of solvent structuring in DES and solute interactions in DES, with state-of-the-art organometallic synthesis and functional meta-materials preparation, and crucially focuses on implementation of manufacturing solutions to allow these fundamental investigations a route into real industrial practices. Use of molecular assemblies in DES and novel continuous manufacturing technologies will open the way to design of cheaper, safer, more environmentally friendly reaction processes, leading to new functional materials and greener routes to pharmaceuticals, agrochemicals and other fine chemicals.

There is enormous potential for widespread impact of deep eutectic solvents in manufacturing, underpinning technological developments over several sectors and thereby contributing to a productive UK economy. Applications of DES in separations, fine chemical synthesis and materials production are rapidly developing in research labs and the project proposed here will propel this work into advanced manufacturing platforms capitalising on the flexibility, low cost and enhanced safety aspects of these solvents. The impact of this work will be felt in a variety of areas, most directly in pharmaceuticals manufacturing and in transport by providing improved materials for emissions control. However, the new fundamental understandings and technologies we will generate will allow for rapid exploitation and commercialisation of DES based processes, in fields from separations to formulation.

Increasingly stringent environmental legislation and the push for low-carbon, resource-efficient sustainable economies within Europe (eg COM2010/614) are driving the search for low cost solvents from renewable sources - replacing toxic organic solvents with safer, eco-friendlier alternatives is a key tenet of Green Chemistry. Tuneable DES from renewable sources are of rising interest, and when paired with flow manufacturing platforms offer innovative new ways to direct syntheses that also allow efficient solvent recycling and product separations. Understanding DES participation in reactions offers the exciting possibility of tailoring solvent-solute interactions to promote desired reaction pathways and self-assembly, reducing waste and utilizing low energy routes to materials. This work will establish underpinning design rules and enabling flow manufacturing technologies for DES-enabled benchtop organometallic catalysed synthesis and synthesis of meta-materials used in technologies from solar water splitting, to photovoltaics and catalysis.

Societal impacts are likely on a longer timescale. Replacement of organic solvents with DES in flow enabling high selectivity and specificity for syntheses will reduce waste, save energy, enhance safety and lower costs for drugs. New materials for exhaust remediation produced via sustainable DES in flow manufacturing will provide lower cost solutions for greener transport reducing atmospheric pollution, improving health. As processes involving DES are implemented by industry, product manufacturing will change, incorporating these more economical and sustainable processes that will have a positive impact on wealth and the environment. We have two industrial partners, Johnson Matthey and Janssen who see immediate potential benefits to this work, in meta-materials and pharmaceuticals, the focus areas of this proposal, but these are only two of the broad potential applications for these solvents and the advanced manufacturing solutions which facilitate their use. Both partners will provide industry pull advice and assistance to this project to focus our efforts towards economically feasible routes to commercialisation of DES in flow systems for these areas. To ensure our research is widely disseminated we will maintain a project website and twitter account highlighting our own and other developments on DES as well as publishing via open access routes. We also plan to hold a 'Power Symposium' in year 2 on DES design and applications to highlight challenges within the manufacturing sector, connecting with both industrial stakeholders and expert researchers on DES.
This grant will also provide training and networking opportunities to three PDRAs, enabling them to launch their careers in this exciting, broad and rapidly growing field. The UK will therefore benefit from trained researchers, and potentially licensable new technologies utilising deep eutectic solvents. We will also pursue a variety of public engagement activities and media coverage to ensure the wider public recognises the implications of this project.