Christoph Gürtler, Walter Leitner and team

Using carbon dioxide to make greener plastics

Technical field
Chemical engineering
Covestro Deutschland AG
German chemists Christoph Gürtler , Walter Leitner and team have pioneered a technique to use CO₂ as a building block for creating plastics, reducing energy usage and recycling waste CO₂. Their work has solved a decades-old problem and is paving the way to more sustainable manufacturing.

Finalists for the European Inventor Award 2021

Plastics manufacturing consumes 6-8% of worldwide oil production, contributing significantly to our overall carbon footprint. Polyurethanes - a class of polymers widely used in foams and plastics to make furniture, insulating material, sports equipment and components within electronic devices - also need large amounts of crude oil to source the carbon required for manufacture, rendering the process environmentally unsustainable. In the past, scientists have explored ways to make CO₂-based polymers, but these proved too expensive and energy-intensive to be viable for industrial application.

In 2007, Christoph Gürtler , Walter Leitner and team began working on a problem that had puzzled researchers since the 1960s. As participants in an industry-academia collaboration between RWTH Aachen University and Bayer MaterialScience (later renamed Covestro), they attempted to use chemical catalysts (which trigger or speed up reactions between other substances without becoming part of the end products) to convert CO₂ into valuable materials. Their extensive expertise helped them succeed where others had failed. The method they developed uses specific catalysts to drive reactions between CO₂ and a crude oil derivative. The resulting material - a chain-like molecule with two or more hydroxyl groups, otherwise known as a polyol - can be used as a precursor for producing the materials used in everyday items. Their patented technique helps to reduce the fossil feedstock required to make a chemical precursor by up to 20%,and provides a use for waste gas CO₂. 

Harnessing green chemistry to boost sustainability

Cardyon® - the CO₂-based patented product developed by Gürtler, Leitner and team - was commercialised by Covestro, formed in 2015 as a spin-off of German multinational Bayer AG. The company is a polyurethane market leader and employs more than 16 500 staff globally. Their invention is used in flexible foams for mattresses and padded sports flooring, as an additive for detergents and, in the future, in stretchy textile fibres in clothing such as socks, waistbands and bra straps. Covestro now produces up to 5 000 tonnes of cardyon® at its pilot plant in Dormagen, Germany, using CO₂ from a nearby ammonia production facility, and is leading 13 partners in an EU-funded project to transform CO₂ from steel mill processing into polyurethane precursors. 

Today, the two inventors continue to work in their different spheres: Gürtler is Head of Catalysis and Technology Incubation at Covestro, while Leitner is Director of Molecular Catalysis at the Max Planck Institute for Chemical Energy Conversion as well as Chair of Technical Chemistry and Petrochemistry at RWTH Aachen University. Their collaboration shows the value of combining fundamental knowledge from academia with industrial know-how to solve key challenges. Both are convinced that green chemistry has a crucial role to play as industry makes the transition towards carbon neutrality.

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