Activity and selectivity modifications produced by coke deposition on mono- and bimetallic reforming catalysts

QUERINI, C.A.; FIGOLI, N.S.; PARERA, J.M.

APPLIED CATALYSIS A-GENERAL

Año: 1989 vol. 53 p. 53 - 61

0926-860X

Modifications of the activity and selectivity of mono- and bimetallic catalysts induced by coke were studied. A mixture of cyclohexane and n-pentane was used as the feed in order to follow typical reforming reactions such as hydrogenolysis, dehydrogenation, isomerization and ring contraction. The catalysts were previously coked by means of accelerated deactivation tests. There were significant modifications to the catalyst selectivity with coke content. The ring contraction of cyclohexane into methylcyclopentane was the only reaction for which the coked catalysts were more active than the fresh catalysts. The concept of "indirect control" of the metal function in the conversion of cyclohexane into methylcyclopentane is introduced in order to explain that the metal is not the location where the slowest step in the above conversion occurs, but that where cyclohexane is rapidly converted into benzene