Looking for safe bio-based alternatives to toluene and NMP
The hazardous substances toluene and nitrogenous NMP are used worldwide at a very large scale as solvents in for example paints, coatings and medicines. The EU is researching whether the use of these substances, which are considered to be toxic, can be restricted. In the EU-BBI project RESOLVE Wageningen Food & Biobased Research is developing safe alternatives for toluene and NMP with technically similar properties. In addition, these alternatives are sustainable, because they are manufactured from vegetable, carbohydrate-rich residual flows.
‘RESOLVE touches an important subject’, says Laura Thissen of Wageningen Food & Biobased Research. ‘The annual use of NMP and toluene amounts to hundreds of thousands to millions of tonnes, while they are extremely harmful to the health of people working with these substances. So it’s with good reason that these feature on the List of Substances of Very High Concern. In this project, it is our aim to develop technically similar non-toxic alternatives with which we also make sustainability progress. We’re cooperating with York University and a dozen European companies in this interesting project.’
Thissen thinks that the project partners have opted for a revolutionary approach: ‘When looking for alternatives, substances with a molecular structure similar to toluene and NMP are usuallylooked at. This is understandable, since it is then relatively simple to use these alternatives in current production processes. However, it is quite difficult to develop safe lookalikes, because the toxicity is related to the molecular structure. RESOLVE aims for developing alternatives with a completely different chemical structure, avoiding the chemical groups that make toluene and NMP toxic.’
Promising platform chemicals
Researchers from Wageningen Food & Biobased Research and York University have identified a number of promising bio-based platform chemicals which can be converted into high-quality solvents. Thissen: ‘We are looking at carbohydrate-rich residual flows at an industrial scale as source material. For example, there is an abundant supply of sugar beet pulp and its quality is stable. This is required for scaling. We expect to be able to develop fully bio-based alternatives to toluene and NMP.’
Thissen expects that the promising bio-based alternatives can be tested at pilot scale level in 2019 or 2020. Then it will also become clear if their production is technically and economically feasible. Toxicological safety testing will be done before scaling up. If RESOLVE becomes a success, this might cause a breakthrough in the market of solvents. Thissen: ‘This would be beneficial to the health of many thousands of people who now still work with very toxic substances, and also have sustainability benefits.’