De‐t‐butylation of t‐butylbenzenes was carried out over a pyridine poisoned solid acidic catalyst to determine the effect of acid strength distribution on the reaction rate and catalyst fouling rate. The acid sites on the solid acidic catalyst were divided into three groups by their acid strength. Moderate acid sites, which were effective for the de‐t‐butylation but ineffective for the coke formation, were exclusively left on the catalyst surface by the partial poisoning. It is found that the present modification of the catalyst is useful in preparing an acid catalyst without catalyst fouling by coke deposition.

The decomposition reaction of p–t‐butylcumene and t‐butylbromobenzene have been carried out over pyridine poisoned silica‐alumina and HY zeolite in order to examine the effect of acid strength on selectivity. Since the catalyst deactivation rate for isomerization over the poisoned silica‐alumina was greater than that of de‐t‐butylation in the reaction of p–t‐butylcumene, the selectivity of de‐t‐butylation gradually improved with process time. In the reaction of t‐butylbromobenzene over poisoned HY zeolite, the de‐bromination rate was suppressed by the poisoning because the nature of active sites was different between silica‐alumina and HY zeolite. The poisoned HY zeolite was found to be favorable for the de‐t‐butylation of halogenated‐t‐butylbenzenes.