Abstract
The catalytic activity of decationated zeolite for isomerization of o-xylene was investigated at 340∼460°C using a pulse method, and the homogeneity of the active surface was qualitatively confirmed from the activation energy obtained and the result of partial piosoning with ammonia.
The reaction rate sharply increased with the increase of the ion exchange level of the zeolite, of which the heat of adsorption and apparent activation energy were substantially independent. Increasing the pretreatment temperature of the zeolite above 400°C, showed no appreciable change of the activation energy, whereas the reaction rate decreased considerably. The catalytic activity of decationated zeolite was reversibly poisoned by the introduction of ammonia to the reaction system. Postulating the Langmuir assumption for the effective adsorption of ammonia on the active surface, the reaction rate was proportionally reduced to the coverage by ammonia and the adsorption constant of ammonia was almost independent of the ion exchange level and of the pretreatment temperature.
