CATALYSIS AND SUPRAMOLECULAR CHEMISTRY
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3) Aqueous heterogeneous catalysis
Our work in this field consisted in examining the dispersion stability and catalytic performance of solid supports in aqueous phase. In this context, two approaches have been developed. The first approach is to disperse and stabilize in aqueous phase palladium catalysts on activated carbon (Pd/C) (to know more...), or Ru(0) ruthenium nanoparticles (to know more...) using modified cyclodextrins. The latter proved to be poly-functional entities, acting both as stabilizing and dispersing agents of the catalyst in water and as molecular receptors capable of bringing the substrate to the active metal center where it could be selectively recognized (Figure 5). Parts of these works have been realized in collaboration with Pr.Fourmentin’s team (Université du Littoral, Dunkerque, France) [P2, P3] and Pr. Roucoux’s team (ENSCR, Rennes, France) [P1, P4].
The second approach is to use mesoporous activated carbon (Figure 6) whose hydrophilic/hydrophobic nature allows for adsorption into the pores of both the organic substrate and water soluble catalyst. The activated carbon alveolar structure (Figure 7) ensures rapid diffusion of compounds, which results in increased catalytic activity [P5, P6, P7].
- P 1. Supramolecular shuttle and protective agent: a multiple role of methylated cyclodextrins in the chemoselective hydrogenation of benzene derivatives with ruthenium particles.
A. Nowicki, Y. Zhang, B. Léger, J.P. Rolland, H. Bricout, E. Monflier, A. Roucoux, Chem. Commun. (2006) 296-298.
- P 2. Eco-efficient catalytic hydrodechloration of carbon tetrachloride in aqueous cyclodextrin solutions.
A. Cassez, A. Ponchel, H. Bricout, S. Fourmentin, D. Landy, E. Monflier,
Catal. Lett. 108 (2006) 209-214.
- P 3. Solubilisation of chlorinated solvents by cyclodextrin derivatives. A study by static headspace gas chromatochraphy and molecular modelling.
S. Fourmentin, M. Outirite, P. Blach, D. Landy, A. Ponchel, E. Monflier, G. Surpateanu,
J. Hazard. Mater. B 141 (2007) 92-97.
- P 4. Methylated Cyclodextrins: an efficient protective agent in water for zerovalent ruthenium nanoparticles and a supramolecular shuttle in alkene and arene hydrogenation reactions.
A. Nowicki-Denicourt, A. Ponchel, E. Monflier, A. Roucoux,
Dalton Trans. (2007) 5714-5719.
- P 5. Activated carbon as a mass-transfer additive in aqueous organometallic catalysis
N. Kania, B. Léger, S. Fourmentin, E. Monflier, A. Ponchel,
Chem. Eur. J. 2010, 16, 6138-6141.
- P 6. An ordered hydrophobic P6mm mesoporous carbon with graphitic pore walls and its application in aqueous catalysis
N. Gokulakrishnan, N. Kania, B. Léger, C. Lancelot, D. Grosso, E. Monflier, A. Ponchel,
Carbon, 49 (2011) 1290-1298.
- P 7. Scope and limitation of activated carbons in aqueous organometallic catalysis
N. Kania, N. Gokulakrishnan, B. Léger, S. Fourmentin, E. Monflier, A. Ponchel,
J. Catal, 278 (2011) 208–218.