INCAPE   05401
INSTITUTO DE INVESTIGACIONES EN CATALISIS Y PETROQUIMICA "ING. JOSE MIGUEL PARERA"
Unidad Ejecutora - UE
artículos
Título:
Effect of hydrogen on the cracking mechanisms of cycloalkanes over zeolites
Autor/es:
PEDRO CASTAÑO; JOSÉ M. ARANDES; MARTÍN OLAZAR; JAVIER BILBAO; BÁRBARA PAWELEC; ULISES SEDRAN
Revista:
CATALYSIS TODAY
Editorial:
ELSEVIER SCIENCE BV
Referencias:
Lugar: Amsterdam; Año: 2010 vol. 150 p. 363 - 367
ISSN:
0920-5861
Resumen:
Hydrocracking of secondary interest refinery streams (high aromatic content) can yield valuableproducts for transportation and petrochemical industry. In order to promote the hydrogenation and cracking steps, a bifunctional catalyst (metal + acid function) is required. We have studied the effect of the operating conditions on cycloalkane (product of aromatic hydrogenation) ring opening over a monofunctional HZSM-5 zeolite, by focusing on the effect of hydrogen in the cracking mechanisms. Methylcyclohexane has been selected as the test reactant and the conditions used corresponds to temperature, 250–450 8C; space velocity, 0.7–1.1 h-1; pressure, 2–80 bar; hydrogen/methylcyclohexane molar ratio, 1–79; conversion, 0–100% (integral reactor). At these conditions the zeolite catalyses hydrogenation as well as cracking (bifunctional capabilities), thus the cracking mechanisms are directly affected by hydrogen as products (alkenes) and intermediates (carbenium ions) are saturated. The overall effect of rising  hydrogen partial pressure is an enhancement of (hydro)isomerization and monomolecular cracking, that is, an increase of the yield/selectivity of methane, ethane, penthane and isoalkanes.