Zeolite promoted hydrocarbon conversion catalysts

Claim 1

A method for preparing a zeolite promoted hydrocarbon cracking catalyst comprising a zeolite dispersed in an inorganic matrix, which comprises: (a) preparing an alkali metal faujasite having a silica-alumina ratio of from about 3.0 to 6.0 by reacting silicate, aluminate, in aqueous alkali metal hydroxide solution to obtain a reaction mixture containing zeolite crystals suspended in an aqueous solution of mother liquor which contains 25 to 50 gms. per liter Na 2 O and 50 to 100 gms. per liter SiO 2 dissolved therein, (b) separating the zeolite from its mother liquor, (c) combining the mother liquor with additional silicate, and a desired quantity of clay, and then gelling by lowering pH thereof to from about 12.0 to 10.5 by the addition of carbon dioxide or mineral acid; (d) adding a sufficient quantity of sodium aluminate to the reactant mixture to provide from about 5 to 40% of the alumina present in the matrix of the finished catalyst; (e) aging the gelled silicate mixture for a period of from about 15 to 60 minutes at a temperature of 70° to 125° F.; (f) adding an aluminum salt to the aged mixture and adjusting the pH to from about 5.5 to 7.5; (g) adding sodium Y-type zeolite to the gelled reaction mixture; (h) washing said composition to remove soluble impurities; (i) exchanging said composition with a solution of rare earth ions having a pH of 4.5 to 5.25; and (j) recovering the catalyst product.

Claim 2

A method for preparing a zeolite promoted hydrocarbon cracking catalyst comprising a zeolite dispersed in an inorganic matrix, which comprises: (a) preparing an alkali metal faujasite having a silica-alumina ratio of from about 3.0 to 6.0 by reacting silicate, aluminate, in aqueous alkali metal hydroxide solution to obtain a reaction mixture containing zeolite crystals suspended in an aqueous solution of mother liquor which contains 25 to 50 gms. per liter Na 2 O and 50 to 100 gms. per liter SiO 2 dissolved therein, (b) separating the zeolite from its mother liquor, (c) combining the mother liquor with additional silicate, and a desired quantity of clay, and then gelling by lowering pH thereof to from about 12.0 to 10.5 by the addition of carbon dioxide or mineral acid; (d) adding a sufficient quantity of sodium aluminate to the reactant mixture to provide from about 5 to 40% of the alumina present in the matrix of the finished catalyst; (e) aging the gelled silicate mixture for a period of from about 15 to 60 minutes at a temperature of 70° to 125° F.; (f) adding an aluminum salt to the aged mixture and adjusting the pH to from about 5.5 to 7.5; (g) adding sodium Y-type zeolite to the gelled reaction mixture; (h) washing said composition to remove soluble impurities; (i) exchanging said composition with a solution of rare earth ions having a pH of 4.5 to 5.25; and (j) recovering the catalyst product.