ABSTRACT
Industrially, the hydrolysis of halobenzenes into phenols can be carried out in the presence of solid catalysts. Most of the solids which can catalyze the reaction contain copper, and it has been shown recently that copper-zeolites are among the most active. Regarding the mechanism of the reaction, two different processes can be considered: the nucleophilic aromatic mechanism and the arynic mechanism. The former occurs generally when the aromatic ring bears electron-withdrawing groups and leads in principle to a single hydrolysis product. The latter is usually involved when the reaction is carried out in the presence of a strong base and leads in principle to several products. HZSM5 was synthesized according to the procedure described by Guth and Caullet using colloidal silica, sodium aluminate, and tetrapropylammonium bromide. The sodium form of the zeolite was then exchanged with an ammonium chloride solution and calcined at 520°C under dry airflow.
