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REnewable SOLVEnts with high performance in application and improved toxicity profile

Periodic Reporting for period 3 - ReSolve (REnewable SOLVEnts with high performance in application and improved toxicity profile)

Reporting period: 2020-06-01 to 2020-11-30

The ReSolve project aimed to replace two hazardous solvents, currently used in large volumes within European industries, with safer alternatives derivable from non-food carbohydrates. There is an urgent need to replace these solvents due to their health and environmental impacts, which has resulted in increasing regulation of their use across the globe. The new, safer solvents developed in ReSolve have a wide range of applications and the project aimed to demonstrate their sustainability, low impact on health and high performance. The research will affect thousands of downstream businesses and consumers, who use the products made using the traditional solvents. ReSolve will have a far wider impact than on replacing these two solvents alone – the substitution methodology developed can be applied to a large number of important but problematic solvents. The reduction in health impact of replacement of such solvents is vital to the millions of European citizens that are routinely exposed to solvents as part of their job or in domestic applications.

The solvents that the project aimed to replace were NMP (N-methyl-2-pyrrolidone) and toluene. NMP is currently used in the production of cleaning products, paint removers, pharmaceuticals and inks among other important commercial products. It is used in the electronics, pharmaceutical, industrial (and household) cleaning and agrochemical industries. It is used by consumers as well as by professional workers. However, it is easily absorbed through the skin and it may damage fertility or the unborn child. Therefore, it has been identified as a Substance of Very High Concern (SVHC) under the EU’s flagship chemicals legislation REACH. Toluene, used in the production of products like adhesives, paints/coatings and plastics is easily inhaled. It is suspected to cause damage to the unborn child, may cause damage to the central nervous system and it is not allowed (<0.1% by weight) in adhesives and spray paints intended for sale to the public.

The main objectives were achieved:

• Produce at least two new carbohydrate-based solvents to replace toluene or NMP in specific applications.
Two key candidates, one each to replace toluene and NMP, were produced and tested. 2,2,5,5-tetramethyloxolane (TMO) was found to be widely applicable in replacing toluene while CyreneTM showed utility in replacing NMP in several applications. Several other candidates were found useful in replacing NMP in some applications.

• Produce the two new solvents at a suitable volume to allow testing of the solvents in a relevant industrial application.
Two key candidates were produced at pilot-scale and tested at an industrial setting within the project and by numerous external parties.

• Establish a new, cost-effective testing strategy to allow the rapid evaluation of the toxicological safety of any potential new solvents.
A new testing strategy combining in vitro and in silico methods was developed and used to analyse 129 samples, including current solvents, replacement candidates and starting materials.

• Evaluate how the new solvents would perform in environmental and economic terms, including market uptake and costs/methods of large-scale production.
Economic and environmental assessments were completed, allowing candidates to be benchmarked. A market study was delivered and a production demo plant for two candidates was designed.
Over 280 potential candidates, from six possible starting materials, were analysed using computer modelling. Over 50 substances were synthesised to evaluate the modelling and focus on the most promising options. All new substances were extensively purified and submitted for toxicity screening. Existing toxicological in vitro test methods were adapted to suit the challenges posed by the analysis of solvents and an in silico safety assessment strategy developed. The results of the in vitro and in silico assessments were combined to an integrated final outcome, which was used to help to select the most promising candidates to continue in the project, by highlighting those with an unfavourable toxicity profile.

A preliminary process design and techno-economic and environmental assessment was made to help narrow down the candidate list. The focus of the preliminary LCA was on identifying environmental hotspots to guide the optimisation of the concept process designs. Benchmarking against toluene and NMP provided an insight regarding the solvents overall environmental preferability. Building on the preliminary assessments, and the results from the other work areas, two candidates were chosen for more detailed process design, techno-economic and environmental assessments. In addition, a study was performed for the conceptual design of a production process at a demo scale for these two candidates.

To identify possible applications and potential market stakeholders, a market analysis was conducted. This first focused on the toluene and NMP markets to identify the most promising market segments for solvent replacements by analysing the European value chain including suppliers, consumers and market demand. An overview of current bio-based solvents markets, their environmental and low human and ecotoxicity preferability and the drivers and barriers for their market uptake were evaluated.

The project was represented at over 50 conferences, workshops and events. The major dissemination deliverable, a stakeholder workshop, was held as a pre-event at the EFIB 2019 conference. To date, 6 peer-reviewed articles have been published, with more in preparation. The project will continue to disseminate the project outcomes to both industry and the wider public through communication and exploitation activities.
Substitution of the harmful solvents with something similar only provides a short term solution, as the limited alternatives generally have similar toxicity issues among other negative issues and will likely also become restricted. The ReSolve project has provided two “key” safer solvents (TMO and CyreneTM) which have been tested in key applications, their sustainable production from biomass evaluated in terms of cost and impact and target markets identified. Twelve other potential solvents have been identified and extensively evaluated as the ReSolve studies have confirmed that one bio-based solvent cannot replace the targets in all the applications, particularly in the case of NMP. Seeking substitutes for toluene has proven more straightforward, with one leading candidate and several very promising back-ups. Some candidates from ReSolve were found to not be ideal for replacing toluene or NMP, yet hold promise as replacements for other solvents.

Substitution of the hazardous solvents will have a major health impact in terms of the reduced exposure to harmful chemicals for both workers and the wider public. ReSolve products will have positive regional and local impacts e.g. through reutilisation of local residues, as production uses non-food agricultural and forestry feedstocks. However, a key challenge will be the cost of production. Targeting an existing (or developing) industry by-product makes this more viable. These challenges are now being addressed in the BBI JU Flagship project ReSolute which builds on the success of ReSolve in the case of the NMP replacement (CyreneTM) and will take its production up to 1000T pa as well as develop new supply chains on the way to full commercialisation.
ReSolve project summary diagram