METHOD FOR AMMONIUM-ACTIVATING ZEOLITE UNDER EXISTENCE OF GASEOUS AMMONIA

摘要

PURPOSE: To efficiently activate a deactivated catalyst by bringing the zeolite catalyst of a specific compsn. into contact with an aq. ammonium soln. of pH >=8 for 2 to 72 hours at 40 to 200 deg.C under an ammonium atmosphere. CONSTITUTION: The acid activity of the zeolite catalyst compsn. is improved by bringing the catalyst consisting of crystalline zeolite having a lattice/silica alumina molar ratio of at least 100 and a constraint index of 1 to 12 and an inorg. oxide binder contg. aluminum such as an aluminum oxide binder into contact with the aq. ammonium soln. of pH >=8 for 2 to 72 hours at 40 to 200 deg.C under the ammonia atmosphere. The ammonium soln. described above adequately contains (NH4 )2 CO3 , NH4 OH and/or (NH4 )2 HPO4 . The zeolite includes zeolite ZSM-5, ZSM-11, ZSM-12 or the like.