Design of a Heterogeneous Catalyst Based on Cellulose Nanocrystals for Cyclopropanation: Synthesis and Solid‐State NMR Characterization |
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| Authors: | Jiquan Liu Andreas Plog Pedro Groszewicz Li Zhao Dr. Yeping Xu Dr. Hergen Breitzke Prof. Dr. Annegret Stark Dr. Rudolf Hoffmann Dr. Torsten Gutmann Prof. Dr. Kai Zhang Prof. Dr. Gerd Buntkowsky |
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| Affiliation: | 1. Eduard‐Zintl‐Institute for Inorganic Chemistry and Physical Chemistry, Technische Universit?t Darmstadt, Alarich‐Weiss‐Strasse 8, 64287 Darmstadt (Germany);2. Center of Smart Interfaces, Technische Universit?t Darmstadt, Alarich‐Weiss‐Strasse 10, 64287 Darmstadt (Germany);3. College of Agriculture, Engineering and Science, School of Engineering, University of KwaZulu‐Natal, Howard College Campus, Durban (South Africa);4. Eduard‐Zintl‐Institute for Inorganic Chemistry and Physical Chemistry, Technische Universit?t Darmstadt, Alarich‐Weiss‐Strasse 12, 64287 Darmstadt (Germany);5. Ernst‐Berl‐Institute for Chemical Engineering and Macromolecular Science, Technische Universit?t Darmstadt, Alarich‐Weiss‐Strasse 8, 64287 Darmstadt (Germany);6. Wood Technology and Wood Chemistry, Georg‐August‐Universit?t G?ttingen, Büsgenweg 4, 37077 G?ttingen (Germany) |
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| Abstract: | Heterogeneous dirhodium(II) catalysts based on environmentally benign and biocompatible cellulose nanocrystals (CNC‐Rh2) as support material were obtained by ligand exchange between carboxyl groups on the CNC surface and Rh2(OOCCF3)4, as was confirmed by solid‐state 19F and 13C NMR spectroscopy. On average, two CF3COO? groups are replaced during ligand exchange, which is consistent with quantitative analysis by a combination of 19F NMR spectroscopy and thermogravimetry. CNC‐Rh2 catalysts performed well in a model cyclopropanation reaction, in spite of the low dirhodium(II) content on the CNC surface (0.23 mmol g?1). The immobilization through covalent bonding combined with the separate locations of binding positions and active sites of CNC‐Rh2 guarantees a high stability against leaching and allows the recovery and reuse of the catalyst during the cyclopropanation reaction. |
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| Keywords: | cellulose cyclization nanoparticles rhodium supported catalysts |
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