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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Catalysis letters 21 (1993), S. 309-320 
    ISSN: 1572-879X
    Keywords: Sol-gel catalysts ; platinum-tin catalysts ; platinum dispersion ; X-ray diffraction ; energy dispersive X-ray analysis ; EDX analysis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Highly dispersed platinum was found in Pt-Sn/Al2O3 catalysts prepared by the sol-gel method, i.e., cogelation of aluminum tri-sec-butoxide and tetrabutyltin and subsequent impregnation with hexachloroplatinic acid. X-ray diffraction studies showed that the cell parameter of pure platinum is not modified in bimetallic Pt-Sn samples. Moreover, energy dispersive X-ray analysis studies (EDX) showed that platinum, but not tin, was detected in the catalysts where tin was incorporated by the sol-gel coprecipitation of tin and aluminum. Incorporation of tin into the alumina network is suggested.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Journal of sol gel science and technology 8 (1997), S. 321-325 
    ISSN: 1573-4846
    Keywords: magnesia-silica mixed oxides ; sol-gel magnesia-silica ; magnesia-silica acidity ; sulfated magnesia-silica ; isopropanol decomposition
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Mg-Si binary oxides were prepared by the sol-gel method, using magnesium diethoxide and tetraethoxysilane as starting materials. Mg-Si mixed oxides were prepared at pH3 and 9 at nominal concentrations of 1.3, 4.0, and 6.7 mole% MgO. Density and strength of the acid sites were determined by pyridine thermal programmed desorption. Comparable Lewis acidity was found in pH3 and 9 preparations. However, when the samples were sulfated with sulfuric acid, strong Bronsted acidity was developed, reaching a maximum at 6.7 mole% MgO. The strong acidity of sulfated samples was corroborated using the isopropanol decomposition reaction as catalytic test. Similar conversions are obtained at 100°C on sulfated samples, whereas 260°C are required for non-sulfated ones.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Journal of sol gel science and technology 8 (1997), S. 321-325 
    ISSN: 1573-4846
    Keywords: magnesia-silica mixed oxides ; sol-gel magnesia-silica ; magnesia-silica acidity ; sulfated magnesiasilica ; isopropanol decomposition
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Mg−Si binary oxides were prepared by the sol-gel method, using magnesium diethoxide and tetraethoxysilane as starting materials. Mg−Si mixed oxides were prepared at pH3 and 9 at nominal concentrations of 1.3, 4.0, and 6.7 mole% MgO. Density and strength of the acid sites were determined by pyridine thermal programmed desorption. Comparable Lewis acidity was found in pH3 and 9 preparations. However, when the samples were sulfated with sulfuric acid, strong Bronsted acidity was developed, reaching a maximum at 6.7 mole% MgO. The strong acidity of sulfated samples was corroborated using the isopropanol decomposition reaction as catalytic test. Similar conversions are obtained at 100°C on sulfated samples, whereas 260°C are required for non-sulfated ones.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
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