Chemistry and environment

The research currently being conducted at Chimie ParisTech in synthesis largely deal with the operation of catalytic systems to improve the yield, but also to better control the regioselectivity of the reaction or the microstructure in the case of polymers. The great diversity of the types of catalysts and the growing interest of the industry make this a real solution for more efficient and greener syntheses in the future (reduction in the amount of waste, number of steps, etc.)

The COCP (Chimie Organométallique et Catalyse de Polymérisation) team, led by Professor Christophe Thomas, is studying how to make eco-compatible syntheses with bioresources to make biodegradable polymers. To achieve this, the team is thinking about both the design of the polymer and its end of life (biodegradability, recycling, recovery, etc.), which happens to be dependent upon its use. On the design side, the team relies on the functionalization of bioresources by catalysis and on the development of tandem catalytic systems.

These tandem systems allow us to use the same catalytic system to perform several steps of the same synthesis. However, this requires many challenges, such as the stabilization of the catalyst in the medium, or the management of secondary and intermediate products, which must be compatible with the catalytic activity and not react with the main cycle. Tandem catalysis offers the possibility of synthesizing polymers from one-pot bioresources, which limits exposure to toxic products during production, energy consumption, waste production and energy barriers encountered in the cycle. Eventually, this would allow the formation of more complex macromolecules, which are currently inaccessible in synthesis with the methods we use now. New polymers produced from diacids from bioresources have already been made this way.

The team’s expertise in organometallic chemistry has also brought it to work on the modification of catalysts in situ, with a controlled transformation. The objective is to limit compatibility problems with certain functions and to reduce the impact of the structure of the reactive intermediates encountered. This suggests the possibility of producing from bioresources since they often prove to be highly functionalized and provided with numerous sensitive stereogenic centers.

This interest in bioresources and molecules is also shared by the CSB2D (Catalyse, Synthèse de Biomolécules et Développement Durable) team, led by Dr. Virginie Vidal. Specialized in the total synthesis of biomolecules, it uses metallo-organocatalytic methods to achieve coupling or functionalization in a more selective and controlled way. For example, obtaining different products by modifying operating conditions is a challenge in organic chemistry and is a powerful tool in divergent synthesis, which organic chemists have managed to achieve by studying the divergent catalytic activity of silver and gold on oxidative cycles. As for its work in organocatalysis, the team uses a Lewis acid to conduct alkyne-aldehyde couplings with good regioselectivity under mild conditions and without metal catalysts. Finally, it relies on already acquired synthetic methodologies to optimize reactions through the use of transitive metal compounds, such as ruthenium.

This particular focus demonstrates how chemistry integrates the environment in all of its fields of activity. At the request of manufacturers, the COCP team is improving existing catalytic systems by replacing toxic metals such as tin with more environmentally-friendly alternatives. This research should ultimately limit the exposure to pollutants and therefore their impact on public health, but should also help counteract this pollution and treat it.