A model fouling reaction in a zeolite catalyst

A zeolite catalyst became rapidly fouled when used for the alkylation of benzene by cyclohexene at temperatures below 245°C. At higher temperatures, the extent of fouling was limited and at 450° C, a steady rate of formation of cyclohexyl benzene was observed. The fouling material was identified as a mixture of di‐ and tri‐alkyl benzene, trapped because of size in the void spaces of the zeolite crystal. A mathematical model based on the forms of Langmuir‐Hinshelwood kinetics was used to describe the fouling phenomenon. The effect of the internal mass transport has also been investigated by means of a mathematical model. This model indicates that transport between the surface of the zeolite crystal and interior reaction sites is rapidly blocked by a layer of fouling material.