A bio-based solvent for paints and varnishes

In this apparatus, the production of the new solvent dimethylfuran is being tested on a small scale at the RUB.
Credit: Mareile Silvia Rohlf

So far, only a small part of the established solvents has been bio-based. The project team wants to change that - rethinking the entire process chain from start to finish.

Around 20 million tons of solvents are consumed worldwide every year, of which only a small part has been produced bio-based to date. An international project team wants to provide an alternative to established solvents with dimethylfuran. The substance is bio-based and biodegradable. The Ruhr University Bochum (RUB), the Fraunhofer Institute for Interfacial and Bioprocess Engineering IGB in Straubing and the industrial partner AURO Plant Chemistry AG are cooperating for the project. The German Research Foundation is funding the project from October 2022 to September 2025 with 214,200 euros.

The starting point for the work is the substance 5-hydroxymethylfurfural (HMF), which can be obtained from biomass and converted into dimethylfuran (DMF). Researchers at RUB around Prof. Dr. Martin Muhler and Dr. Baoxiang Peng from the Chair of Technical Chemistry has already been established in a previous project. In the current research project, they want to optimize the catalyst and the reaction conditions in order to lay the foundation for an industrial production of DMF. The IGB team around Dr. Harald Strittmatter and Ferdinand Vogelgsang from the innovation fields "Bioinspired Chemistry" and "Sustainable Catalytic Processes" will scale up the catalytic reaction to a 40-fold larger scale. Together with the industrial partner AURO, the scientists will finally provide ready-made recipes for the use of DMF as a solvent and test them in the production of natural colors.

The aim of the team is to cover the entire process chain from catalyst synthesis to product purification.

Optimize the catalyst and the process

The Bochum chemists use palladium nanoparticles as a catalyst. Compared to previous work, for example, they want to lower the reaction temperature from 160 to 130 degrees Celsius in order to reduce energy costs. They are also looking for a mild solvent in which the reaction can take place and from which the end product can be easily separated. "We want to use water as a solvent because the reaction should be as safe as possible for people and the environment," says Baoxiang Peng.

In the second step, the project partners at Fraunhofer IGB investigate whether the process works not only in the test tube, but also on a larger, industry-relevant scale. Thanks to the interdisciplinary interaction of the two research areas involved, the institute has the necessary skills. Engineer Vogelgsang and chemist Strittmatter bring their respective expertise in the areas of catalysis and organic synthesis into the project. "This is how we scale the conversion from HMF to DMF to a liter scale and then clean up the product," explains Vogelgsang. “Then we test the end product as a solvent and as an extractant for natural substances before it goes to our industrial partner."

Promotion
The German Research Foundation is funding the project "Dimethylfuran as a sustainable follow-up product of 5-hydroxymethylfurfural - manufacture and applications of a bio-based solvent" as a trilateral project. The aim is to transfer knowledge from previously funded projects into the application. Universities, Fraunhofer institutes and application partners work together for this.

Source/Credit: Ruhr University Bochum | Julia Weiler

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