Patent ID: 6506703
Filing Date: 2003-01-14
Classification: B01J,C10G

Abstract:
An ion exchange method for dispersing noble metals into catalyst support aggregates comprising a binder and a zeolite containing original non-noble metal exchangeable cations, by contacting said catalyst support aggregates with an aqueous loading solution comprising catalytic noble metals present in cationic form and a source of non-noble metal cations, under conditions effective for said noble metal cations to ion exchange into said zeolite thereby displacing said original non-noble metal cations from said zeolite into the aqueous loading solution, and for a time sufficient so that the ion exchange of said noble metals into the said zeolite is substantially complete, wherein the improvement comprises(a) formulating said aqueous loading solution to contain a quantity of non-noble metal cations such that after ion exchange of said noble metals into the zeolite is substantially complete the gram equivalents of said non-noble metal cations remaining in the catalyst support which are not ionically bound into said zeolite is between about 2 and about 6 times the gram equivalents of said original non-noble metal cations displaced by said noble metal cations, and (b) maintaining the endpoint pH of said loading solution when the ion exchange is complete at between about 10.0 and about 11.5.