Heraeus Precious Metals: New precious metal catalyst to make cellulose usable as raw material for chemicals

Hanau, 5th October 2022

  • The new ruthenium-based precious metal catalyst offers the best conditions for efficient formation of DFF from 5-HMF for versatile use in bio-based products

The negative developments of climate change and the ever-increasing CO₂ emissions require a renewal of traditional petroleum-based chemistry. For this reason, Heraeus Precious Metals initiated a development program for precious metal-based catalysts several years ago. The program aims to convert various renewable raw materials such as biomass, CO₂ or plastic waste into value-added, sustainable chemicals. With the help of the new precious metal catalyst from Heraeus Precious Metals, the residual forestry product cellulose can be made usable as a raw material for chemicals.

Ruthenium-based precious metal catalyst for efficient conversion of 5-HMF to DFF

Catalyst for Cellulose

The molecule 5-hydroxymethylfurfural, 5-HMF, is obtained from cellulose and serves as a starting material for 2,5-diformylfuran (DFF). DFF is a highly flexible chemical that can be used for a variety of bio-based products, including the production of formaldehyde-free phenolic resins as glues for particleboard. The new ruthenium-based precious metal catalyst from Heraeus Precious Metals ensures the efficient formation of DFF from 5-HMF. "Studies have shown that ruthenium has immense potential in the catalytic conversion of sustainable feedstocks, such as biomass," explains Dr. Gisa Meissner, project manager in the research department for chemical precious metal-based heterogeneous catalysts at Heraeus Precious Metals.

Catalyst performance depends, among other things, on the solvent used, the precious metal precursor solutions and the intrinsic properties of the support. Researchers at Heraeus Precious Metals have found that a special alumina oxide support loaded with ruthenium leads to the highest HMF conversion of 97 percent with a DFF selectivity of 100 percent. This support contributes to a reaction rate almost twice as high compared to other catalysts. In addition, the catalyst with a five percent ruthenium loading shows the highest activity in the conversion of 5-HMF to DFF. Through a selective washing process, this 5%Ru/Al2O3 catalyst finds multiple reuses.

At the end of their life cycle, the heterogeneous precious metal catalysts from Heraeus are subject to an ecologically and economically optimal recycling system: the deactivated catalyst is separated from the reaction mixture and fed into the recycling loop. The recycled precious metal thus obtained can in turn be used in new heterogeneous catalysts, reducing the overall carbon footprint by up to 98 percent compared to primary metals from mining. "Our precious metal catalysts enable the efficient recycling of biomass into sustainable products," says Dr. Meissner. "At the same time, our customers benefit from a recycling strategy that brings not only economic but also, and especially, ecological advantages."

Heraeus experts are continuously working to make platform chemicals accessible by converting additional biobased and renewable raw materials through catalytic processes.