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Modification and characterization of sites giving acid cracking on aluminium oxide supports; Modification et caracterisation des sites responsables du craquage acide sur des supports a base d`alumine

Abstract

The aim of this work is to characterize the surface acid properties of {gamma} alumina, especially the nature, the amount, the strength and the environment of acid sites. The techniques that have been used are: the thermo-desorption of trimethyl-phosphine followed by {sup 31}P MAS NMR, the infrared spectroscopy, the n-heptane cracking, the modification of {gamma} alumina by the addition of chlorine, silicon and alkali (K{sup +}, Na{sup +}), alkaline-earths (Mg{sup 2+}, Ca{sup 2+}), lanthanum (La{sup 3+}) cations. The combination of these techniques has allowed to identify the surface acid properties of {gamma} alumina through the n-heptane transformation reactions under reforming conditions. We have shown that Lewis acidity is responsible for cracking reactions leading to C{sub 1}-C{sub 6} and C{sub 2}-C{sub 5} whereas the cracking of n-heptane producing C{sub 3}-C{sub 4} is due to Broensted acid sites. The isomerization and cyclization reactions both require weaker Broensted acid sites than cracking leading to C{sub 3}-C{sub 4}. The mechanisms involved in the formation of products of these reactions have been identified. Despite the complexity of surface acid properties of {gamma} alumina, this study has determined the environment of catalytically active sites, considering the presence of cation vacancies. (author) 206 refs.
Authors:
Publication Date:
Oct 23, 1997
Product Type:
Thesis/Dissertation
Report Number:
IFP-44186
Reference Number:
SCA: 400201; 020400; PA: FRC-98:003354; EDB-98:106869; SN: 98002000046
Resource Relation:
Other Information: TH: These (D. es Sc.); PBD: 23 Oct 1997
Subject:
40 CHEMISTRY; 02 PETROLEUM; CATALYTIC REFORMING; AROMATICS; ALUMINIUM OXIDES; CATALYST SUPPORTS; HEPTANE; CATALYTIC CRACKING; X-RAY FLUORESCENCE ANALYSIS; ABSORPTION SPECTROSCOPY; COMBUSTION; SPECIFIC SURFACE AREA; NUCLEAR MAGNETIC RESONANCE; PHOSPHORUS 31; INFRARED SPECTRA; CHEMICAL PREPARATION; CHLORINE; IMPREGNATION; POTASSIUM; SODIUM; CALCIUM; MAGNESIUM; CRYSTAL DOPING; CHLORINATION; SINTERING; LANTHANUM; SILICON; PARTIAL PRESSURE; BENCH-SCALE EXPERIMENTS; BROENSTED ACIDS; LEWIS ACIDS; VACANCIES
OSTI ID:
655572
Research Organizations:
Institut Francais du Petrole (IFP), 92 - Rueil-Malmaison (France); Ecole Nationale Superieure du Petrole et des Moteurs (ENSPM), 92 - Rueil-Malmaison (France); Universite Pierre et Marie Curie, 75 - Paris (France)
Country of Origin:
France
Language:
French
Other Identifying Numbers:
Other: ON: DE98775497; TRN: FR9803354
Availability:
OSTI as DE98775497
Submitting Site:
FR
Size:
200 p.
Announcement Date:

Citation Formats

Guillaume, D. Modification and characterization of sites giving acid cracking on aluminium oxide supports; Modification et caracterisation des sites responsables du craquage acide sur des supports a base d`alumine. France: N. p., 1997. Web.
Guillaume, D. Modification and characterization of sites giving acid cracking on aluminium oxide supports; Modification et caracterisation des sites responsables du craquage acide sur des supports a base d`alumine. France.
Guillaume, D. 1997. "Modification and characterization of sites giving acid cracking on aluminium oxide supports; Modification et caracterisation des sites responsables du craquage acide sur des supports a base d`alumine." France.
@misc{etde_655572,
title = {Modification and characterization of sites giving acid cracking on aluminium oxide supports; Modification et caracterisation des sites responsables du craquage acide sur des supports a base d`alumine}
author = {Guillaume, D}
abstractNote = {The aim of this work is to characterize the surface acid properties of {gamma} alumina, especially the nature, the amount, the strength and the environment of acid sites. The techniques that have been used are: the thermo-desorption of trimethyl-phosphine followed by {sup 31}P MAS NMR, the infrared spectroscopy, the n-heptane cracking, the modification of {gamma} alumina by the addition of chlorine, silicon and alkali (K{sup +}, Na{sup +}), alkaline-earths (Mg{sup 2+}, Ca{sup 2+}), lanthanum (La{sup 3+}) cations. The combination of these techniques has allowed to identify the surface acid properties of {gamma} alumina through the n-heptane transformation reactions under reforming conditions. We have shown that Lewis acidity is responsible for cracking reactions leading to C{sub 1}-C{sub 6} and C{sub 2}-C{sub 5} whereas the cracking of n-heptane producing C{sub 3}-C{sub 4} is due to Broensted acid sites. The isomerization and cyclization reactions both require weaker Broensted acid sites than cracking leading to C{sub 3}-C{sub 4}. The mechanisms involved in the formation of products of these reactions have been identified. Despite the complexity of surface acid properties of {gamma} alumina, this study has determined the environment of catalytically active sites, considering the presence of cation vacancies. (author) 206 refs.}
place = {France}
year = {1997}
month = {Oct}
}