PhD proposal 2022

Laboratory : Catalysis, Polymerization, Processes and Materials (CP2M).

Funding : Ministère de l'Enseignement supérieur et de la Recherche

Contract : Doctoral contract (3 years)

Discipline : Catalysis / Polymer / Physical-chemistry

Deadline for application : April 1, 2022

Start date : September 1, 2022

Continuous fixed bed reactors are frequently used in the chemical industry for multiphase reactions. They allow to improve the control of the reaction conditions in order to maximize the conversions and the yields but also to overcome the separation stages between the catalyst and the products [1]. These processes use structured catalytic supports (SCS) in order to have a high specific surface and an efficient mixing of the reactants while limiting the pressure drops. Among the variety of SCS used, open cell polymeric foams (e.g. PU foam, melamine…) are prime candidates, fulfilling all these characteristics [2]. In addition, these new elastomeric SCS enable the use of in-situ controlled deformation within the reactor, thus intensifying the transfer of reactants.

The scientific challenges consist in: (i) performing a robust functionalization of these SCS-elastomers without modifying their elastic properties and, (ii) implementing them in a dedicated reactor. Within the framework of this PhD, the adhesion of the catalyst on these new SCS-elastomers will be achieved using two versatile and complementary techniques: (i) using polydopamine, a bio-inspired polymer with remarkable properties of adhesion and (ii) from diazonium salts which can lead to the formation of covalently grafted polymers films. Polydopamine coating allow a very good adhesion on any type of support [3] but show leaching problems, whereas the grafting by diazonium salts would make it possible to have functional groups that are covalently bound but must be adapt for each type of support [4]. The objective is to combine the two methods thus benefiting from the advantages of both (strong PDA adhesion and diazonium covalent grafting). Indeed, the release of the PDA mainly concerns the outer layers, which are less strongly bound together than is the initial monolayer in contanct with the substrate. After release of the PDA coating, a very adherent monolayer of PDA is obtained which can be used as a support for grafting with diazonium salts allowing the introduction of numerous functionalities (see figure above). This method can thus be adapted to the many elastomeric materials available for different multiphase catalysis reactions (hydrogenation/oxidation). Thanks to the approach proposed in this PhD, the catalyst can be either in the form of nanoparticles (Ag, Au), or organic (metal complexes) and therefore covalently grafted onto the film.

The second objective of this PhD consists in using the elastic properties of functionalized SCS-elastomers in a new type of innovative reactor currently being developed within the MMAGIC team (the crankshaft piston reactor) [5]. A detailed characterization (in the process engineering sense) of the processes will be carried out and the prepared SCS will be tested for the targeted applications. The success of this transversal project will be facilitated by the combination of complementary skills from the two teams recently merged within the CP2M Laboratory (polymer surface functionalization for the PolyCatMat team and reactor design/process engineering for the MMAGIC team) .

Skills and Experience of the future PhD student

Students with a master's degree or an engineer in materials science, chemistry, physical chemistry. Experience in chemical engineering and polymer chemistry is desired. Experience with catalysis and surface chemistry will be a plus. Finally, the candidate must demonstrate great curiosity and an interest in reactor design/process engineering.

Contact

        PhD supersivor : David Edouard (david.edouard@univ-lyon1.fr)

        PhD co-supersivors : Fabrice Brunel (fabrice.brunel@univ-lyon1.fr),

        Elodie Bourgeat Lami

        Pascal Fongarland

References

[1] Mills, et al., 1980, Chem. Eng. Sci. 35, 2267 –2279.

[2] (a) E. Pardieu, et al , Chem. Commun. 2016, 52, 4691. (b) L. Lefebvre et al . Environ. Chem. Eng. 2017, 5, 79. (c) A. Ait Khouya, et al , Chem. Commun. 2019, 55, 11960.

[3] Lee et al. (2007) Science, 318, 426-430

[4] Mohamed et al. (2015). Adv. Colloid Interface Sci., 225, 16-36.

[5] Thèse de Laura Birba (ANR POLYCATPUF)