Patent ID: 6407025
Filing Date: 2002-06-18
Classification: B01J,C01B

Abstract:
A method of producing an ion-exchanged material comprising the steps:(a) contacting at least one synthetic zeolite selected from the group consisting of structure types FAU, EMT, LTA, CHA, MOR, and combinations thereof and containing sodium cations, potassium cations or mixtures thereof with a source of polyvalent cations, thereby replacing some of said sodium cations, potassium cations or mixtures thereof with polyvalent cations and producing a partially polyvalent cation-exchanged zeolite, (b) drying said partially polyvalent cation-exchanged eolite and subsequently heat treating said dried, partially polyvalent cation exchanged zeolite by elevating the temperature stepwise to a temperature in the range of about 30 to about 190Â° C., (c) contacting the heat-treated zeolite with a source of ammonium cations, thereby replacing at least part of the cations, potassium cations or mixtures thereof remaining on said zeolite with ammonium cations, and producing polyvalent cation and ammonium cation ion-exchanged zeolite, and (d) contacting said polyvalent cation and ammonium cation ion-exchanged zeolite with a source of Group 1A cations other than sodium and potassium cations in a reaction zone under conditions which effect the replacement with ammonium cations with at least one of said Group 1A cations other than sodium and potassium cations and the removal of at least one reaction product from said reaction zone.