Artículo
The influence on selectivity of the aluminum content in the matrix of FCC catalysts
de la Puente, Gabriela
; Falabella Sousa Aguiar, Eduardo; Figueiredo Costa, Alexandre; Sedran, Ulises Anselmo
Fecha de publicación:
03/2003
Editorial:
Elsevier Science
Revista:
Applied Catalysis A: General
ISSN:
0926-860X
Idioma:
Inglés
Tipo de recurso:
Artículo publicado
Clasificación temática:
Resumen
The influence that both the type of matrix and the interaction between zeolite and matrix have on the selectivity of FCC catalysts was studied by means of the conversion of cyclohexene at 300 ◦C on a large number of samples in which the matrix was changed. Silica/alumina matrices had 0, 12 and 25% of alumina, and catalysts were subjected to steaming of varying severity followed by acid extraction in some samples to remove extraframework aluminum species (EFAl). Resulting catalysts were characterized by various techniques. It was confirmed that hydrogen transfer does not depend directly on the type of coordination of the aluminum atoms in the sample, but rather on the density of paired sites in the zeolite component. It was possible to define the selectivity of reaction pathways (SRP) as an index to describe the relative importance of the processes of<br />desorption via hydride transfer to yield cyclohexane against retention of the cation cyclohexil via isomerization and further reaction. A high value of SRP would mean that a given catalyst has a lower ability to retain adsorbed species that can be subjected to additional reactions like, in this particular reaction, isomerization and further proton transfer to the catalyst surface, or cracking. The index was shown to increase whereas the relative amount of octahedral aluminum atoms decreased, a fact that can be associated to the formation of a new silica/alumina phase. Such phase would be formed by means of the reaction of aluminum extracted from the zeolite upon steaming and silica present in the matrix.
Palabras clave:
Cracking
,
Selectivity
,
Matrix
,
Fcc
,
Cyclohexene
,
Y Zeolite
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Articulos(INCAPE)
Articulos de INST.DE INVEST.EN CATALISIS Y PETROQUIMICA "ING. JOSE MIGUEL PARERA"
Articulos de INST.DE INVEST.EN CATALISIS Y PETROQUIMICA "ING. JOSE MIGUEL PARERA"
Citación
de la Puente, Gabriela; Falabella Sousa Aguiar, Eduardo; Figueiredo Costa, Alexandre; Sedran, Ulises Anselmo; The influence on selectivity of the aluminum content in the matrix of FCC catalysts; Elsevier Science; Applied Catalysis A: General; 242; 2; 3-2003; 381-391
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