Characterization of catalysts based on titanium silicalite, TS-1, by physicochemical techniques
- Universite Pierre et Marie Curie, Paris (France); and others
Two titanium silicalite-1 samples (A and B) with similar particle sizes have been characterized by powder X-ray diffraction, FT-IR and FT-Raman spectroscopy, UV-visible diffuse reflectance spectroscopy (DRS), transmission electron microscopy with X-ray energy dispersion spectrometry (to analyze grains and ultramicrotomed sections), and xenon-129 NMR. Activity and selectivity for the epoxidation of oct-1-ene by phosphate-free 30% aqueous hydrogen peroxide have been investigated. The critical factors governing the activities of the samples with molar ratios Si: Ti {approx} 39 (sample A) and 32 (sample B) are the distribution of titanium within the microporous materials and within the extra framework titania (crystalline anatase or amorphous phase as evidenced by UV-visible DRS, FT-Raman spectroscopy, and electron microscopy). Xenon-129 NMR chemical shifts, {delta}{sub exp} =f(n) (n =number of adsorbed xenon atoms per gram of anhydrous sample), depend dramatically on extra framework impurities and Ti(IV) dispersion. Pure silicalite and nearly perfect TS-1 (sample A) are not differentiated by xenon-129 NMR, a fact which is tentatively attributed to the {open_quotes}atomic dispersion{close_quotes} of the titanium in sample A, as evidenced by X-ray EDS and by the channel dimensions. 58 refs., 9 figs., 5 tabs.
- OSTI ID:
- 476836
- Journal Information:
- Journal of Catalysis, Journal Name: Journal of Catalysis Journal Issue: 1 Vol. 165; ISSN 0021-9517; ISSN JCTLA5
- Country of Publication:
- United States
- Language:
- English
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