- Title
- Imidazole-functionalized polymer microspheres and fibers–useful materials for immobilization of oxovanadium (IV) catalysts
- Creator
- Walmsley, Ryan S, Ogunlaja, Adeniyi S, Coombes, Matthew J, Chidawanyika, Wadzanai J U, Litwinski, Christian, Torto, Nelson, Nyokong, Tebello, Tshentu, Zenixole R
- Subject
- To be catalogued
- Date
- 2012
- Type
- text
- Type
- article
- Identifier
- http://hdl.handle.net/10962/246041
- Identifier
- vital:51431
- Identifier
- xlink:href="https://doi.org/10.1039/C2JM15485D"
- Description
- Both polymer microspheres and microfibers containing the imidazole functionality have been prepared and used to immobilize oxovanadium(IV). The average diameters and BET surface areas of the microspheres were 322 μm and 155 m2 g−1 while the fibers were 1.85 μm and 52 m2 g−1, respectively. XPS and microanalysis confirmed the incorporation of imidazole and vanadium in the polymeric materials. The catalytic activity of both materials was evaluated using the hydrogen peroxide facilitated oxidation of thioanisole. The microspheres were applied in a typical laboratory batch reactor set-up and quantitative conversions (>99%) were obtained in under 240 min with turn-over frequencies ranging from 21.89 to 265.53 h−1, depending on the quantity of catalyst and temperature. The microspherical catalysts also proved to be recyclable with no drop in activity being observed after three successive reactions. The vanadium functionalized fibers were applied in a pseudo continuous flow set-up. Factors influencing the overall conversion and product selectivity, including flow rate and catalyst quantity, were investigated. At flow rates of 1–4 mL h−1 near quantitative conversion was maintained over an extended period. Keeping the mass of catalyst constant (0.025 g) and varying the flow rate from 1–6 mL h−1 resulted in a shift in the formation of the oxidation product methyl phenyl sulfone from 60.1 to 18.6%.
- Format
- computer, online resource, application/pdf, 1 online resource (9 pages), pdf
- Publisher
- Royal Society of Chemistry
- Language
- English
- Relation
- Journal of Materials Chemistry, Walmsley, R.S., Ogunlaja, A.S., Coombes, M.J., Chidawanyika, W., Litwinski, C., Torto, N., Nyokong, T. and Tshentu, Z.R., 2012. Imidazole-functionalized polymer microspheres and fibers–useful materials for immobilization of oxovanadium (IV) catalysts. Journal of Materials Chemistry, 22(12), pp.5792-5800, Journal of Materials Chemistry volume 22 number 12 p. 5792 2012 1364-5501
- Rights
- Publisher
- Rights
- Use of this resource is governed by the terms and conditions of the Royal Society of Chemistry Terms and Conditions Statement (https://0-www.rsc.org.wam.seals.ac.za/help-legal/)
- Rights
- Open Access
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Collections
Tshentu, Zenixole Richman (Dr)
Nyokong, Tebello (Distinguished Professor)
RU DST/NRF SARChI for Medicinal Chemistry and Nanotechnology
RU Department of Chemistry
| Thumbnail | File | Description | Size | Format | |||
|---|---|---|---|---|---|---|---|
| View Details | SOURCE1 | Imidazole-functionalized polymer microspheres and fibers–useful materials.pdf | 843 KB | Adobe Acrobat PDF | View Details |