Preparation of sulfated zirconia catalysts with improved control of sulfur content, III. Effect of conditions of catalyst synthesis on physical properties and catalytic activity1Presented at the 15th Meeting of the North American Catalysis Society, Chicago, IL, 20 May 1997, Abstract No. P196.12Part II: D. Fărcaşiu, J.Q. Li, Appl. Catal. A 154 (1997) 173.2

Fǎrcaşiu, D.; Li, Jing Qi

doi:10.1016/s0926-860x(98)00197-5

Cited by 44 publications

(40 citation statements)

References 43 publications

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“…Secondly, gaseous SO 3 is used instead of a liquid sulfation agent such as H 2 SO 4 or (NH 4 ) 2 SO 4 solution [28 -30]. Finally, the sulfation does not require a final calcination step, which is indispensable for a standard sulfation procedure [29,31,32]. The applicability of the newly developed sulfation method was proved for a wide range of zirconia samples, including active pure tetragonal sulfated zirconia (SZ) and inactive almost monoclinic or partially tetragonal non-sulfated samples (SZ-BW and ZrO 2 , respectively).…”

Section: Resultsmentioning

confidence: 99%

Activation of Light Alkanes on Sulfated Zirconia

Olindo

Lercher

2006

Chemie Ingenieur Technik

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The present contribution reviews recent experiments of our group towards the synthesizing and understanding of highly reactive sulfate-modified zirconia. It is shown that in the absence of Pt, the catalytic activity depends upon the ability to oxidize a small fraction of the alkanes to alkenes. The alkenes form sec-carbenium ions with Brønsted acid sites and isomerize via carbenium ion/alkoxy intermediates. Alkane activation/conversion propagates through hydride transfer from n-butane to the tert-butyl carbenium ion. A kinetic model accounting for the elementary steps is proposed and catalyst preparation strategies are reported.

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Section: Resultsmentioning

confidence: 99%

Activation of Light Alkanes on Sulfated Zirconia

Olindo

Lercher

2006

Chemie Ingenieur Technik

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“…For toluene benzylation, conversion increases linearly in the range 0.01-0.023 %S/(m 2 g -1 ), this should correspond to densities of 2-4 S atoms nm -2 [33]. The conversion of methylcyclopentane however passes through a maximum at an intermediate sulfate content [34]. The n-butane isomerization activity of Pt-doped sulfated zirconia increases with increasing sulfur content up to a level of ca.…”

Section: Structure-activity Relationshipsmentioning

confidence: 97%

“…The surface sulfate content of the calcined materials (as measured by photoelectron spectroscopy) increases initially more steeply with increasing H 2 SO 4 molarity than the total sulfate content [52]. The sulfate content increases with the amount of sulfuric acid used for the impregnation [34]. More sulfate can be deposited (solvent evaporation) than adsorbed (filtration) [124].…”

Section: Commercially Available Precursorsmentioning

confidence: 99%

Oxo‐Anion Modified Oxides

Jentoft

2008

Handbook of Heterogeneous Catalysis

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The sections in this article are Introduction Classification Variety of Materials and Focus Target Properties Structure–Activity Relationships Effect of Sulfate and Other Oxo‐Anions Preparation Routes Formation of Primary Solid Formation of Pure Hydrous Zirconia Formation of Sulfate‐Containing Hydrous Zirconia Template‐Directed Formation of Primary Solid Commercially Available Precursors Anion‐Modification of Primary Solid Addition of Oxo‐Anions to Primary Solid in Liquid Medium Sulfation of Primary Solid via Gas Phase Introduction of Oxo‐Anions Using Solid Precursors Addition of Promoters (Optional) Promoters Structure–Activity Relationships Effect of Promoters Addition of Promoters Calcination Events Occurring During Calcination Effect of Bed Volume and Packing Effect of Calcination Temperature on Physical Properties Effect of Calcination Temperature on Catalytic Performance Effect of Holding Time Calcination: A Summary Sulfation of Thermally Treated Crystalline Oxides Sulfation with Aqueous Solutions (Solid–Liquid Phase) Sulfation via Gas Phase (Solid–Gas Phase) Sulfation of Zirconia using Solid Sulfate Precursors Addition of Noble Metals Activation Summary

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“…The tetragonal phase is presumed to be essential for a highly active sulfated zirconia catalyst [25,[52][53][54]; samples containing a monoclinic fraction are always less active in alkane isomerization than purely tetragonal materials [26,28]. However, the tetragonal phase does not guarantee a high activity [55].…”

Section: Zirconia Phase Chemistry and Catalytic Activitymentioning

confidence: 99%

The Balance Between Reactivity and Stability of Modified Oxide Surfaces Illustrated by the Behavior of Sulfated Zirconia Catalysts

Klose-Schubert

Jentoft

2011

Top Catal

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The stability of a series of sulfated zirconia catalysts, promoted with up to 2 wt% iron or manganese, in their calcined state was investigated. Phase composition, nature of surface sulfate species, degree of hydroxylation, and butane isomerization activity changed duri ng aging over months in various atmospheres and during milling. The metastability of small oxide particles is discussed, including literature data on alumina, titania and other oxides. Catalytically active fractions of a material easily transition into more stable, less active forms.

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Cited by 44 publications

References 43 publications

Activation of Light Alkanes on Sulfated Zirconia

Activation of Light Alkanes on Sulfated Zirconia

Oxo‐Anion Modified Oxides

The Balance Between Reactivity and Stability of Modified Oxide Surfaces Illustrated by the Behavior of Sulfated Zirconia Catalysts

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