You need JavaScript to view this

Contribution to the study of the catalytic properties of stoichiometric and non- stoichiometric alumina. Catalysis of the hydrogenation of ethylene and of the formic acid decomposition; Contribution a l'etude des proprietes catalytiques d'alumines stoechiometriques et non stoechiometriques. Catalyse de l'hydrogenation de l'ethylene et de la decomposition de l'acide formique

Abstract

The alumina, of the delta crystalline form and composed of non-porous spherical grains of 150 A diameter, is cold pressed in a die at a pressure of 4 metric tons/sp.cm. On heating to 500 deg C in a high vacuum, the surface lattice of the alumina loses oxygen and becomes an n-type semi-conductor. The same treatment at 800 deg C causes a loss of aluminium and the appearance of p-type semi-conductivity. These samples are used as catalysts for reactions involving the hydrogenation of ethylene and the decomposition of formic acid. The kinetic study of the ethylene hydrogenation reaction at 500 deg C shows that when this gas is not in excess in the reaction mixture, the rate of reaction is proportional to the partial pressure of the hydrogen. The rate constants at 500 deg C are of the same order of magnitude, irrespective of the previous treatment of the alumina. This result is due to a compensation effect between the pre-exponential factor and the apparent activation energy. The nature of the various hydrogen adsorption sites is described in each case. The apparent activation energy is a minimum each time that the hydrogen is adsorbed covalently; it is a maximum for  More>>
Authors:
Hilaire, P [1] 
  1. Commissariat a l'Energie Atomique, Saclay (France). Centre d'Etudes Nucleaires
Publication Date:
Jul 01, 1963
Product Type:
Thesis/Dissertation
Report Number:
CEA-R-2260
Resource Relation:
Other Information: TH: These sciences; 104 refs
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; ACTIVATION ENERGY; ALUMINIUM OXIDES; CATALYSIS; CHEMICAL REACTION KINETICS; DECOMPOSITION; ETHYLENE; FORMIC ACID; HYDROGENATION; SEMICONDUCTOR MATERIALS; STOICHIOMETRY
OSTI ID:
20804954
Research Organizations:
CEA Saclay, 91 - Gif-sur-Yvette (France); Feculte des Sciences de l'Universite de Lyon, 69 (France)
Country of Origin:
France
Language:
French
Other Identifying Numbers:
TRN: FR06R2260107176
Availability:
Available from INIS in electronic form
Submitting Site:
FRN
Size:
88 pages
Announcement Date:
Dec 23, 2006

Citation Formats

Hilaire, P. Contribution to the study of the catalytic properties of stoichiometric and non- stoichiometric alumina. Catalysis of the hydrogenation of ethylene and of the formic acid decomposition; Contribution a l'etude des proprietes catalytiques d'alumines stoechiometriques et non stoechiometriques. Catalyse de l'hydrogenation de l'ethylene et de la decomposition de l'acide formique. France: N. p., 1963. Web.
Hilaire, P. Contribution to the study of the catalytic properties of stoichiometric and non- stoichiometric alumina. Catalysis of the hydrogenation of ethylene and of the formic acid decomposition; Contribution a l'etude des proprietes catalytiques d'alumines stoechiometriques et non stoechiometriques. Catalyse de l'hydrogenation de l'ethylene et de la decomposition de l'acide formique. France.
Hilaire, P. 1963. "Contribution to the study of the catalytic properties of stoichiometric and non- stoichiometric alumina. Catalysis of the hydrogenation of ethylene and of the formic acid decomposition; Contribution a l'etude des proprietes catalytiques d'alumines stoechiometriques et non stoechiometriques. Catalyse de l'hydrogenation de l'ethylene et de la decomposition de l'acide formique." France.
@misc{etde_20804954,
title = {Contribution to the study of the catalytic properties of stoichiometric and non- stoichiometric alumina. Catalysis of the hydrogenation of ethylene and of the formic acid decomposition; Contribution a l'etude des proprietes catalytiques d'alumines stoechiometriques et non stoechiometriques. Catalyse de l'hydrogenation de l'ethylene et de la decomposition de l'acide formique}
author = {Hilaire, P}
abstractNote = {The alumina, of the delta crystalline form and composed of non-porous spherical grains of 150 A diameter, is cold pressed in a die at a pressure of 4 metric tons/sp.cm. On heating to 500 deg C in a high vacuum, the surface lattice of the alumina loses oxygen and becomes an n-type semi-conductor. The same treatment at 800 deg C causes a loss of aluminium and the appearance of p-type semi-conductivity. These samples are used as catalysts for reactions involving the hydrogenation of ethylene and the decomposition of formic acid. The kinetic study of the ethylene hydrogenation reaction at 500 deg C shows that when this gas is not in excess in the reaction mixture, the rate of reaction is proportional to the partial pressure of the hydrogen. The rate constants at 500 deg C are of the same order of magnitude, irrespective of the previous treatment of the alumina. This result is due to a compensation effect between the pre-exponential factor and the apparent activation energy. The nature of the various hydrogen adsorption sites is described in each case. The apparent activation energy is a minimum each time that the hydrogen is adsorbed covalently; it is a maximum for an ionic adsorption. All the samples show a strong activity for the decomposition of formic acid and direct this reaction towards the dehydration. The dehydrogenation represents only 5 per cent of the total reaction and is not influenced by the nature of the prior treatment of the alumina. But even in this case, the activation energy for the dehydrogenation is lowered when the hydrogen is adsorbed covalently, without the liberation of electrons. (author) [French] L'alumine, de forme cristalline delta, constituee de grains spheriques non poreux d'un diametre de 150 A, est comprimee a froid dans une motrice sous une pression de 4 t/cm{sup 2}, Lorsque les comprimes sont chauffes a 500 deg C sous vide pousse, il se produit un depart d'oxygene du reseau superficiel d'alumine qui devient semi-conductrice de type n. Le meme traitement, mais a 800 deg C, entraine le depart d'aluminium et une semi-conductivite de type p. Ces echantillons sont utilises comme catalyseurs dans les reactions d'hydrogenation de l'ethylene et de decomposition de l'acide formique. L'etude cinetique de la reaction d'hydrogenation de l'ethylene a 500 deg C montre que, lorsque ce gaz ne se trouve pas en exces dans le melange reactionnel, la vitesse de la reaction est proportionnelle a la pression partielle de l'hydrogene. Les constantes de vitesse a 500 deg C sont du meme ordre de grandeur, quel que soit le traitement anterieur subi par l'alumine. Ce resultat provient d'une compensation entre le facteur preexponentiel et l'energie apparente d'activation. La nature des differents sites d'adsorption de l'hydrogene est precisee dans chaque cas. L'energie apparente d'activation est minimum toutes les fois que l'hydrogene se trouve adsorbe de facon covalente; elle est maximum pour une adsorption ionique. Tous les echantillons font preuve d'une forte activite vis-a-vis de la reaction de decomposition. La deshydrogenation ne represente qu'environ 5 pour cent de la reaction totale et n'est pas influencee par la nature du traitement prealable de l'alumine. Mais encore dans ce cas, l'energie d'activation de la deshydrogenation est abaissee lorsque l'hydrogene se trouve adsorbe de facon covalente, sans liberation d'electrons. (auteur)}
place = {France}
year = {1963}
month = {Jul}
}