CATALYSIS AND UNCONVENTIONAL MEDIA
Leader : Christophe Coutanceau Professor University of Poitiers
Co-leader : Karine De Oliveira Vigier Associate Professor University of Poitiers
Heterogeneous catalysis has always occupied a paramount place in chemical industries. In particular, the stability of solid catalysts and the ease of recovery of reaction products have led to the development of continuous or semi-continuous processes on a large scale. The progressive introduction of renewable carbon (biomass, CO2, waste) in chemical processes, the variability of raw materials (fossil and/or renewable) and the process intensification have radically changed the way how is designed a catalytic reaction and modern heterogeneous catalysis is now facing to new scientific and technologic bottlenecks. In particular, the rational design of novel catalytic surfaces adapted to this change of raw materials, the search of alternative media, the prediction and determination of reaction mechanism at a molecular level (real time in-situ characterization included) are among the biggest challenges faced by modern catalysis.
– Scientific strategy
The scientific strategy of the team relies on the development of catalytic processes in unconventional media. The possible control of catalytic activations by the reaction medium is a promising approach that must lead to the emergence of innovative concepts aiming at 1) adapting the current catalytic processes to the emergence of new and structurally complex raw materials often with variable composition and 2) proposing sustainable and economically viable solutions. Often neglected, the reaction medium, in which a catalyst evolves, can directly impact the individual elementary steps of a catalytic cycle at a molecular level, thus influencing the catalyst activity and selectivity. For instance, a better understanding on how the reaction medium can stabilize/destabilize intermediate species, how it can ease the displacement of thermodynamic equilibrium, how the medium can favour the formation of active species at the catalyst surface and, in general, how the catalytic reaction can be assisted by the reaction media are among fundamental questions that are investigated by the team.
Unconventional media investigated by the team can be of purely chemical nature (deep eutectic solvents, bio-inspired ionic liquids, fluorinating media, sulfuring/desulfuring media, etc…) and/or associated to physical constraints such as electric field (non-thermal plasma), electrode potential (electrocatalysis), microwaves and more recently ultrasounds. In each case, a synergistic effect between those media and catalysts is searched in order to propose new scientific concepts for the selective activation of carbon-heteroatom (C-X with X= O, S, Cl) and heteroatom-hydrogen (X-H with X= O, N, F) bonds. The specificity and the strength of the team reside in the multidisciplinarity of their members allowing an original and innovative approach of the covered research themes. The development of these new concepts should favor not only the emergence of new catalytic processes but also to increase the eco-efficiency of current processes (energy saving, atom economy, etc…). In addition, it should also lead to important innovations for the production of new molecules and materials. These objectives can only be met by combining the various competences of our team.
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To reach the different objectives, the team gathers complementary scientific skills in the field of mechanism investigations and in the rational design of specific/adapted solid catalysts
The determination of reaction mechanisms is crucial for understanding and controlling the influence of unconventional media on the catalytic cycle, both at the molecular or supramolecular levels. To reach such objectives, the team relies on its renowned expertise in the domains of model reaction, computational studies and real-time in-situ characterization.
On the other hand, the nature of investigated reactions, reactants and studied media face the team to major challenges regarding the conception of dedicated catalytic materials. In this context and since a few years, the team is interested in new preparation ways of materials with mineral, organic (polymers, carbons) and hybrid organic-inorganic frameworks. Like in the case of catalytic reactions, preparation of these specific catalytic materials also implies the use of the above-described unconventional media that are mostly used here as templates, organic precursors or for surface functionalization. Clearly, the strategy developed for the preparation of solid catalysts relies on a fundamental and interdisciplinary approach that fully integrates the concept of durability while being in adequation with the various industrial requirements.
All those skills allow the team to bring innovation not only in the field of renewable carbon (biomass, CO2, biogas, waste) but also in the optimization of fossil-based processes. Hence, the most promising research work performed in the team concerns:
- the deconstruction of biopolymers,
- the activation of polyols,
- the activation of recalcitrant molecules (CO2, CH4),
- the furanic platform,
- the chlorine-fluorine exchange reactions and
- hydrotreatment reactions.
From these research investigations, the team has weaved an important network of national and international collaborations with academic and industrial research teams.