Unité de Catalyse et de Chimie du Solide site Artois
Faculté des Sciences de Lens

PUBLICATIONS MARQUANTES 2023 :

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1. «Continuous production of amines directly from alkenes via cyclodextrin-mediated hydroaminomethylation using only water as the solvent»
   T. Friedrich Hubertus Roth, R. Evertz, N. Kopplin, S. Tilloy, E. Monflier, D. Vogt and T. Seidensticker
   Green Chem., 2023, 25, 3680 - doi:10.1039/D2GC04847G
   
   

Aqueous hydroaminomethylation (HAM) is an atom economic route for the efficient production of amines in one reaction step, starting from basic chemicals like alkenes. Herein we present the first successful establishment of a continuous process for a HAM in an aqueous multiphase system. The green mass transfer agents randomly methylated-β-cyclodextrins (CD) enabled the catalyst system consisting of rhodium/sulfoXantphos to achieve high yields of up to 70 % with selectivities of up to 80 % in several continuous experiments with a total run time of more than 220 h. The key here is that water and products have large polarity differences, but the reaction still proceeds effectively due to the addition of cyclodextrin, which made the application of solvents obsolete. The main achievements in this way were to investigate the influence of the randomly methylated-β-cyclodextrin concentration on the reaction rate and the selectivity in batch studies and find promising operating points in the first continuous experiments. In a final experiment, the separation temperature was investigated. It was shown that the catalyst loss into the product phase is enormously small at 0.003 %/h of the initial mass (0.24 % in total), which is the lowest ever reported value for the HAM on this scale. Within a run time of 78 hours, 2.87 kg of tertiary amine were produced using only 0.2 g (>14.000:1) of transition metal, while the loss of rhodium per kg of product produced was mostly around 0.15 mg/kg, suggesting possible economic applicability.





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2. «Efficient removal of fluoride ions present in industrial effluents using metal-organic frameworks of UiO-66-NH₂»
   D. Lacalamita, G. Hoyez, C. Mongioví, A. Ponchel, N. Morin-Crini, C. Rousseau, C. Loup, J. Rousseau, M. Raschetti, E. Monflier, V. Placet, G. Crini
   J. Water Process. Eng., 2023, 53, 103791 - doi: 10.1016/j.jwpe.2023.103791
   
   

In this last decade, numerous works have been published on the use of metal organic frameworks (MOFs) for applications in adsorption field to remove contaminants from aqueous solutions. However, little is known about MOFs as adsorbents for the removal of fluoride ions from real effluents. In this work, a highly porous MOF, UiO-66-NH2, was used for the final treatment of complex discharge waters containing fluoride ions from a surface treatment plant. Batch experiments showed that MOF exhibited high adsorption capacities towards fluoride ions, leading to concentrations under current regulation values. 70–80 % of the fluoride was removed in 60 min using 100 mg of MOF in 50 mL of effluent without changing the industrial initial pH. At the same time, the treatment also completely eliminated traces of aluminium in the discharge water. All the results showed that adsorption onto a non-conventional material such as UiO-66-NH2 can be an interesting tertiary treatment step to remove more pollutant streams from multi-contaminated industrial discharge waters.





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3. «Application of cyclodextrins as second-sphere coordination ligands for gold recovery»
   A. Ponchel, E. Monflier
   Nat. Commun. 2023 14, 1283 - doi: 10.1038/s41467-023-36700-z
   
   

Supramolecular chemistry based on cyclodextrin receptors as second-sphere ligands contribute to developing non-covalent materials with synergistic functionalities. Herein, we comment on a recent investigation of this concept, describing selective gold recovery through a hierarchical host-guest assembly specifically built from β-CD.





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4. «Exploiting poly(e-caprolactone) grafted from hydrohydroxymethylated sunflower oil as biodegradable coating material of water-soluble fertilizers»
   A. El Mouat, T. El Assimi, M. Raihane, J. Ternel, H. Bricout, E. Monflier, S. Tilloy, M. Lahcini
   Progress in Organic Coatings 179 (2023) 107513 - doi: 10.1016/j.porgcoat.2023.107513
   
   

In the present study, hyperbranched poly(ε-caprolactones) were prepared and used as coating materials to prepare slow release diammonium phosphate (DAP) fertilizer. Firstly, the sunflower oil was hydrohydroxymethylated by one-pot two-step process using Rh(acac)(CO)2 as catalyst, and triethylamine as ligand. Next, the bio-based hyperbranched poly(ɛ-caprolactone) (PCL) were prepared in open air by in-situ ring-opening polymerization of ε-caprolactone using hydrohydroxymethylated sunflower oil as macro-initiator and tetra(phenylethynyl)tin (Sn(C ≡ CPh)4) as catalyst. The structures of the prepared polymers (SFO-O-g-PCL) were confirmed by nuclear magnetic resonance (1H NMR) and the infrared spectroscopy (FTIR). Furthermore, molecular weight values around 20.000 g.mol−1 of PCL grafted in SFO-O-g-PCL were obtained, the thermal stability and morphology of the coated film were also evaluated using thermogravimetric analysis (TGA) and scanning electron microscopy (SEM) respectively. The hydrophobic character of the films prepared from SFO-O-g-PCL was confirmed by measuring the contact angle of water droplets. In the second part, the DAP granular fertilizers were uniformly coated by the prepared material (SFO-O-g-PCL) using a laboratory rotary drum. Then the slow release performance in water of the coated and uncoated DAP fertilizer granules was evaluated by tracking the cumulative concentration of P2O5 released. Thus, it was found that only 10 % of P2O5 was released after 2 h of essay from the coated DAP compared to a total release of P2O5 from uncoated DAP (conventional fertilizer) during the same period. This finding opens a wide perspective to combine the advantages of hydrophobic polyesters and bio-based oils to produce biodegradable coating agents.





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5. «New Pyrochlore-like Oxyfluorides Na_2-2xSn_xM₂O₅F₂ (M = Nb⁵⁺ or Ta⁵⁺ and 1 ≤ x ≤ 0) as Potential Candidates for Overall Water Splitting Photocatalysis»
   E. Boivin, S. Saitzek, F. Fauth, M. Huvé, P. Roussel, H. Kabbour
   Chem. Mater., 2023, 35, 2, 447–456 - doi: 10.1021/acs.chemmater.2c02801
   
   

Lone pair containing oxyfluorides have recently emerged as efficient and stable photocatalysts for overall water splitting (OWS). In this work we have obtained several new potential OWS photocatalysts with pyrochlore structure (i.e., Na2–2xSnxM2O5F2 with M = Nb5+ or Ta5+ and 1 ≤ x ≤ 0) through kinetically controlled ion-exchange reaction from Na2M2O5F2. Rietveld refinement of the structures as well as DFT indicate the Sn2+ lone pair stereochemical activity. The partial density of states reveals contributions at the top of the valence band that are mainly composed of a Sn 5s–Sn 5p hybridization through the (O,F) 2p orbitals. This leads to a significant narrowing of the band gap and an improvement of the photoconduction response by a factor ca. 50 with respect to the x = 0 compound, Na2Nb2O5F2. The Mott–Schottky measurements show that all materials possess band edge positions encompassing the thermodynamic redox potential of H+/H2 and O2/H2O. However, the valence band of SnNb2O5F2 may not be oxidative enough to overcome the overpotential associated with the O2– oxidation and hence could be unsuitable for OWS photocatalysis in contrast with Na1.5Sn0.25Nb2O5F2.

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