Claims
- 1. The process for cracking a hydrocarbon feedstock to produce lower boiling hydrocarbons which comprises contacting said hydrocarbon feedstock under catalytic cracking conditions with a catalyst comprising a zeolitic aluminosilicate which has a mole ratio of oxides in the dehydrated state of
- (0.85-1.1)M.sub.2/n O:Al.sub.2 O.sub.3 :xSiO.sub.2
- wherein M is a cation having a valence of "n": x has a value greater than 6.0; the aluminosilicate has an x-ray powder diffraction pattern having at least the d-spacings of Table A, has extraneous silicon atoms in the crystal lattice in the form of framework SiO.sub.4 tetrahedra; and said zeolitic aluminosilicate has been ion-exchanged to contain at least one Group III A cation per unit cell.
- 2. The process of claim 1 wherein the zeolite contains at least two Group IIIA cations per unit cell.
- 3. The process of claim 1 wherein the Group IIIA cation is aluminum.
- 4. The process according to claim 1 wherein the aluminosilicate is ion-exchanged with a multivalent cation selected from the group consisting of cerium, lanthanum, praseodymium, neodymium,, promethium, samarium, europium, galodinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, lutetium, and mixtures thereof.
- 5. The process of claim 1 wherein the zeolitic aluminosilicate is defined as having a chemical composition expressed in terms of mole fractions of framework tetrahedra as
- [Al.sub.(a-N) Si.sub.b+(N-.DELTA.z) .quadrature..sub.z ]O.sub.2
- wherein ".quadrature." denotes the defect sites; "z" is the mole fraction of defect sites in the zeolite framework; "N" is the mole fraction of aluminum tetrahedra removed from the framework; "a" is the mole fraction of aluminum tetrahedra present in the framework of the starting zeolite; "b" is the mole fraction of the silicon tetrahedra present in the framework of the starting zeolite; "(N-.DELTA.z)" is the mole fraction increase in silicon tetrahedra; ".DELTA.z" is the net change in the mole fraction of defect sites; ##EQU5## has a value greater than 3; the change in defect structure factor .DELTA.z is less than 0.08; an increased silicon content in the framework, (N-.DELTA.z)/N, of at least 0.5; and a cation equivalent expressed as monovalent cation species "M" as M.sup.+ /Al, from 0.5 to 1.1 and the characteristic crystal structure of zeolite Y as indicated by an X-ray powder diffraction pattern having at least the d-spacings set forth in Table A.
- 6. The process of claim 5 wherein the change in defect structure .DELTA.z is less than 0.05.
- 7. The process of claim 5 wherein the cation equivalent expresses a multivalent cation species, M.sup.+n /Al, where n is 2 or 3.
- 8. The process of claim 5 wherein the zeolite aluminosilicate has been ion-exchanged with a multivalent cation from the group consisting of cerium, lanthanum, praseodymium, neodymium, promethium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, lutetium and mixtures thereof.
- 9. The process of claim 1 wherein said value for "X" is greater than 7.0.
- 10. The process of claim 5 wherein the SiO.sub.2 to Al.sub.2 O.sub.3 ratio is greater than 7.0.
- 11. The process of claim 1 wherein said catalyst comprises between about 1 and 99 percent by weight of an inorganic oxide matrix.
- 12. The process of claim 11 wherein the inorganic oxide matrix at least one is selected from the group consisting of clays, silicas, aluminas, silica-aluminas, silica-zirconias, silica-magnesias, alumina-borias and alumina-titanias.
- 13. The process of claim 11 wherein said catalyst comprises between about 1 and 90 percent by weight inorganic oxide matrix.
Parent Case Info
This is a division of prior U.S. application Ser. No. 06/721,894, filed Apr. 11, 1985, now U.S. Pat. No. 4,711,864 which is a continuation of application Ser. No. 06/506,446, filed June 2 1983, abandoned.
US Referenced Citations (11)
Divisions (1)
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721894 |
Apr 1985 |
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Continuations (1)
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506446 |
Jun 1983 |
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