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Thermal desorption (TD) study of heterogeneous catalytic reactions--4. Nonuniformity of Pt/. gamma. -Al/sub 2/O/sub 3/ catalysts

Abstract

Programed TD of n-heptane adsorbed on 0.6-3% by wt Pt/..gamma..-Al/sub 2/O/sub 3/ laboratory catalysts with different dispersities of the metallic phase showed the formation of toluene at 160/sup 0/-260/sup 0/C with spectral maxima at about 200/sup 0/ and 230/sup 0/C and a benzene desorption maxima at 300/sup 0/C. The desorption of both benzene and the high-temperature form of toluene decreased with decreased dispersity of the catalyst and was not observed with the catalyst characterized by an average Pt particle size of 1000 A. Toluene adsorbed on the same catalysts showed a TD peak of benzene at 300/sup 0/C. With commercial Pt/Al/sub 2/O/sub 3/ reforming catalysts, up to five toluene desorption peaks were observed at 200/sup 0/-360/sup 0/C, suggesting the presence of active sites with different activities and concentrations on the catalyst surface. Experiments on TD of deuterated n-heptane suggested different reaction mechanisms associated with different types of active sites and the formation of low- and high-temperature forms of toluene. Only the latter had a maximum coinciding with a TD peak of D/sub 2/ (240/sup 0/C), probably formed by dehydrogenation of adsorbed diene or olefin intermediates.
Authors:
Rozanov, V V; [1]  Sklyarov, A V; Gland, J
  1. Inst. Chem. Phys. Acad. Sci. U.S.S.R.
Publication Date:
Oct 01, 1979
Product Type:
Journal Article
Reference Number:
EDB-84-177288
Resource Relation:
Journal Name: Kinet. Katal.; (USSR); Journal Volume: 20:5
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; ALUMINIUM OXIDES; SURFACE PROPERTIES; BENZENE; DESORPTION; HEPTANE; ADSORPTION; PLATINUM; TOLUENE; CHEMICAL REACTION YIELD; CATALYSTS; CATALYTIC EFFECTS; CHEMICAL REACTION KINETICS; HETEROGENEOUS CATALYSIS; TEMPERATURE EFFECTS; ALKANES; ALKYLATED AROMATICS; ALUMINIUM COMPOUNDS; AROMATICS; CATALYSIS; CHALCOGENIDES; ELEMENTS; HYDROCARBONS; KINETICS; METALS; ORGANIC COMPOUNDS; OXIDES; OXYGEN COMPOUNDS; PLATINUM METALS; REACTION KINETICS; SORPTION; TRANSITION ELEMENTS; YIELDS; 400301* - Organic Chemistry- Chemical & Physicochemical Properties- (-1987)
OSTI ID:
6363648
Country of Origin:
USSR
Language:
Russian
Other Identifying Numbers:
Journal ID: CODEN: KNKTA
Submitting Site:
HEDB
Size:
Pages: 1249-1255
Announcement Date:
Apr 01, 1983

Citation Formats

Rozanov, V V, Sklyarov, A V, and Gland, J. Thermal desorption (TD) study of heterogeneous catalytic reactions--4. Nonuniformity of Pt/. gamma. -Al/sub 2/O/sub 3/ catalysts. USSR: N. p., 1979. Web.
Rozanov, V V, Sklyarov, A V, & Gland, J. Thermal desorption (TD) study of heterogeneous catalytic reactions--4. Nonuniformity of Pt/. gamma. -Al/sub 2/O/sub 3/ catalysts. USSR.
Rozanov, V V, Sklyarov, A V, and Gland, J. 1979. "Thermal desorption (TD) study of heterogeneous catalytic reactions--4. Nonuniformity of Pt/. gamma. -Al/sub 2/O/sub 3/ catalysts." USSR.
@misc{etde_6363648,
title = {Thermal desorption (TD) study of heterogeneous catalytic reactions--4. Nonuniformity of Pt/. gamma. -Al/sub 2/O/sub 3/ catalysts}
author = {Rozanov, V V, Sklyarov, A V, and Gland, J}
abstractNote = {Programed TD of n-heptane adsorbed on 0.6-3% by wt Pt/..gamma..-Al/sub 2/O/sub 3/ laboratory catalysts with different dispersities of the metallic phase showed the formation of toluene at 160/sup 0/-260/sup 0/C with spectral maxima at about 200/sup 0/ and 230/sup 0/C and a benzene desorption maxima at 300/sup 0/C. The desorption of both benzene and the high-temperature form of toluene decreased with decreased dispersity of the catalyst and was not observed with the catalyst characterized by an average Pt particle size of 1000 A. Toluene adsorbed on the same catalysts showed a TD peak of benzene at 300/sup 0/C. With commercial Pt/Al/sub 2/O/sub 3/ reforming catalysts, up to five toluene desorption peaks were observed at 200/sup 0/-360/sup 0/C, suggesting the presence of active sites with different activities and concentrations on the catalyst surface. Experiments on TD of deuterated n-heptane suggested different reaction mechanisms associated with different types of active sites and the formation of low- and high-temperature forms of toluene. Only the latter had a maximum coinciding with a TD peak of D/sub 2/ (240/sup 0/C), probably formed by dehydrogenation of adsorbed diene or olefin intermediates.}
journal = []
volume = {20:5}
journal type = {AC}
place = {USSR}
year = {1979}
month = {Oct}
}