Acid Sites in Sulfated and Metal-Promoted Zirconium Dioxide Catalysts
نویسندگان
چکیده
منابع مشابه
In Situ Spectroscopic Investigation of Activation, Start-Up and Deactivation of Promoted Sulfated Zirconia Catalysts
Sulfated zirconia (SZ), unpromoted and promoted with 0.5–2.0 wt% Mn or Fe, was investigated by in situ IR and UV–vis spectroscopy during activation at 723–773 K and interaction with n-butane at 298–323 K. During start-up of the catalysts, the isomerization rate increases with the amount of water that is being formed, consistent with an activation of n-butane via oxidative dehydrogenation. Sulfa...
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Promoted sulfated zirconia samples were prepared by the incipient wetness technique to produce isomerization catalysts which were active for the conversion of n-butane to isobutane at 338K (up to 10% conversion of 1% n-butane, 1atm., 0.25 h(-1) WHSV). The local structure of Fe and Mn in promoted sulfated zirconia was investigated using fluorescence yield XAS. Spectra were taken of calcined samp...
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We discuss the role of QM/MM (embedded cluster) computational techniques in catalytic science, in particular their application to microporous catalysis. We describe the methodologies employed and illustrate their utility by briefly summarising work on metal centres in zeolites. We then report a detailed investigation into the behaviour of methanol at acidic sites in zeolites H-ZSM-5 and H-Y in ...
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Amorphous sulfated zirconium hydroxide was promoted with iron or manganese via the incipient wetness technique, to give 0.5–3.5 weight% promoter in the final catalyst. An exothermic reaction during the calcination temperature ramp (to 823 or 923 K) leads to a rapid overheating (“glow”) of the sample. XRD shows that crystallization starts before and progresses during the overheating. The surface...
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New bis(N,N-trimethylsilylarylamidinate) zirconium dichloride complexes with various carbon substituents were prepared, and their solid as well as solution state structures were studied. In the polymerization of propylene, after activation by MAO, these catalysts provided two fractions. Ether soluble polymers were obtained at a low activity as sticky polymers with lower molecular weights, excep...
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ژورنال
عنوان ژورنال: Journal of Catalysis
سال: 1995
ISSN: 0021-9517
DOI: 10.1006/jcat.1995.1039