Molecular Engineering in Catalysis: Immobilization of Shvo's Ruthenium Catalyst to Silica Coated Magnetic Nanoparticles

Authors

  • Dongmei He
    Affiliation
    Department of Chemistry, City University of Hong Kong, Kowloon, 83 Tat Chee Avenue, Hong Kong, Hong Kong S. A. R.
  • István T. Horváth
    Affiliation
    Department of Chemistry, City University of Hong Kong, Kowloon, 83 Tat Chee Avenue, Hong Kong, Hong Kong S. A. R.; Department of Chemical and Environmental Process Engineering, Faculty of Chemical Technology and Biotechnology, Budapest University of Technology and Economics, H-1111 Budapest, 8 Budafoki Street, Hungary
https://doi.org/10.3311/PPch.16052

Abstract

The functionalized Shvo’s catalyst precursor {3,4-[p-(EtO)3Si(CH2)3OPh]2-2,5-Ph2(η4-C4CO)}Ru(CO)3 (1) was covalently immobilized to the surface of magnetic nanoparticles, MNPs, including magnetite (Fe3O4) and magnetite covered by one, two and three independently added silica (SiO2) coatings (Fe3O4@SiO2, Fe3O4@SiO2@SiO2, Fe3O4@SiO2@SiO2@SiO2) resulting in the corresponding ruthenium catalysts Fe3O4@Ru (2a), Fe3O4@SiO2@Ru (2b), Fe3O4@SiO2@SiO2@Ru (2c), and Fe3O4@SiO2@SiO2@SiO2@Ru (2d). These catalysts were characterized by FT-IR, TEM, EDX, powder XRD, BET surface area analysis and BJH pore size and volume analysis. The catalytic performances of 2a2d were tested for the conversion of levulinic acid (LA) to gamma-valerolactone (GVL) using formic acid (FA) as the hydrogen source. The catalysts were separated from the reaction mixture by using an external magnet. Catalysts on the silica coated MNPs showed higher activity than that of immobilized directly to Fe3O4. There were no significant differences in TONs, TOFs and yields of GVL using catalysts 2b2d. Leaching test of the four catalysts showed that by increasing the number of independent silica coatings on the surface of magnetite significantly decreased iron leaching. The recyclability of 2b was investigated and it was reused several times without significant loss of the catalytic activity. Hot filtration test of 2c and 2d has established that the catalytic activity was due to the supported ruthenium catalyst and not from some active ruthenium species leached from the solid support to the solution under the reaction conditions.

Keywords:

immobilization, Shvo's catalyst, ruthenium, silica coated magnetite, levulinic acid, formic acid, gamma–valerolactone

Citation data from Crossref and Scopus

Published Online

2020-10-21

How to Cite

He, D., Horváth, I. T. “Molecular Engineering in Catalysis: Immobilization of Shvo’s Ruthenium Catalyst to Silica Coated Magnetic Nanoparticles”, Periodica Polytechnica Chemical Engineering, 65(1), pp. 1–11, 2021. https://doi.org/10.3311/PPch.16052

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