Thermosensitive Water-Dispersible Hairy Particle-Supported Pd Nanoparticles for Catalysis of Hydrogenation in an Aqueous/Organic Biphasic System
We report in this article the use of thermosensitive water-dispersible polymer brush-grafted polymeric particles as carriers for Pd nanoparticles for the catalysis of hydrogenation of styrene in an aqueous/organic biphasic system. Thermoresponsive poly(methoxytri(ethylene glycol) methacrylate) brush...
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Published in | Langmuir Vol. 24; no. 11; pp. 5911 - 5918 |
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Main Authors | , , |
Format | Journal Article |
Language | English |
Published |
Washington, DC
American Chemical Society
03.06.2008
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Subjects | |
Online Access | Get full text |
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Summary: | We report in this article the use of thermosensitive water-dispersible polymer brush-grafted polymeric particles as carriers for Pd nanoparticles for the catalysis of hydrogenation of styrene in an aqueous/organic biphasic system. Thermoresponsive poly(methoxytri(ethylene glycol) methacrylate) brushes were grown from initiator-functionalized core−shell cross-linked poly(t-butyl acrylate) (PtBA) particles via surface-initiated atom-transfer radical polymerization. The t-butyl group of PtBA in the core was removed with trifluoroacetic acid, followed by loading of Pd2+ cations through ion exchange. Pd nanoparticles were prepared by reduction of Pd2+ ions with ethanol at 70 °C. Dynamic light scattering studies showed that the Pd nanoparticle-loaded thermosensitive hairy particles in water began to shrink when the temperature was above 30 °C. The supported Pd nanoparticles efficiently catalyzed hydrogenation of styrene in an aqueous/octane biphasic system and were reused five times with no changes in the yields in the first three cycles and slight decreases in the fourth and fifth cycles after the same period of time. Kinetics studies showed that the catalytic activity of Pd nanoparticles was modulated by the phase transition of the thermosensitive brush layer, resulting in a non-Arrhenius dependence of apparent initial rate constant, k app, on temperature. |
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Bibliography: | Hydrolysis of PtBA with CF3COOH; treatment of PTEGMMA under the hydrolysis conditions; 1H NMR spectra of (a) PAA obtained from hydrolysis of PtBA with CF3COOH as catalyst and (b) PtBA; 1H NMR spectra of (a) PTEGMMA and (b) PTEGMMA after treatment under the hydrolysis conditions; plot of Γ/q2 of Pd nanoparticle-embedded PTEGMMA brush-grafted PAA particles at 25 °C (●) and 50 °C (◼) vs q2. This information is available free of charge via the Internet at http://pubs.acs.org. istex:BA49006DEF1D9D607EC3559B0DBB1843ED0A273F ark:/67375/TPS-TF4RJTS7-V ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23 |
ISSN: | 0743-7463 1520-5827 |
DOI: | 10.1021/la800277j |