Title:
Catalytic cracking with zeolite ITQ-13
Kind Code:
A1


Abstract:
A catalytic cracking process is disclosed for feedstock containing hydrocarbons having at least 5 carbon atoms. The feedstock is contacted, under catalytic cracking conditions, with a 9-member ring catalyst composition and, optionally, a large pore molecular sieve, such as zeolite Y.



Inventors:
Chen, Ten-jen (Kingwood, TX, US)
Keusenkothen, Paul F. (Houston, TX, US)
Buchanan, John Scott (Lambertville, NJ, US)
Schmitt, Kirk D. (Pennington, NJ, US)
Application Number:
10/287251
Publication Date:
09/18/2003
Filing Date:
11/04/2002
Assignee:
CHEN TEN-JEN
KEUSENKOTHEN PAUL F.
BUCHANAN JOHN SCOTT
SCHMITT KIRK D.
Primary Class:
Other Classes:
208/118, 208/119
International Classes:
B01J29/70; B01J29/86; C10G11/05; G09F11/00; G09F19/00; (IPC1-7): C10G11/05
View Patent Images:
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Primary Examiner:
GRIFFIN, WALTER DEAN
Attorney, Agent or Firm:
EXXONMOBIL CHEMICAL COMPANY (BAYTOWN, TX, US)
Claims:

We claim:



1. A catalytic cracking process comprising contacting, under catalytic cracking conditions, a feedstock comprising hydrocarbons having at least 5 carbon atoms with a catalyst composition comprising a synthetic porous crystalline material having a multi-dimensional channel system, at least a first parallel set of said channels comprising 9-member rings having a pore size of at least about 3.6 Angstroms.

2. The process of claim 1, wherein at least a second set of said channels comprises 10-member rings.

3. The process of claim 1, wherein the catalyst channel system is 3-dimensional.

4. The process of claim 1, wherein said at least first parallel set of channels has a pore size of at least about 4.0 Angstroms.

5. The process of claim 1, wherein said at least first parallel set of channels has a pore size of at least about 4.2 Angstroms.

6. The process of claim 4, wherein said at least first parallel set of channels has a pore size less than or equal to about 5.0 Angstroms.

7. The process of claim 5, wherein said at least first parallel set of channels has a pore size less than or equal to about 5.0 Angstroms.

8. The process of claim 1, wherein the catalyst is metal-stabilized.

9. The process of claim 8, wherein the catalyst is metal-stabilized with at least one of at least one metal of Group 2a, 3b, 4b, 7b, 8, 1b, 2b, 3a and 5a of The Periodic Table of the Elements.

10. The process of claim 9, wherein the catalyst is metal-stabilized with at least one of copper, phosphorus, iron, silver, magnesium, lanthanum, zinc, aluminum, zirconium, manganese, and cerium.

11. The process of claim 10, wherein the catalyst is metal stabilized with at least one of copper and phosphorous.

12. The process of claim 1, wherein the feedstock is naphtha.

13. The process of claim 1, wherein the feedstock is at least one of gas oil, vacuum gas oil and residual oil vacuum resid.

14. The process of claim 1, which is a fluid catalytic cracking process.

15. The process of claim 1, wherein the catalyst composition is used as an additive catalyst.

16. The process of claim 1, wherein the catalyst composition is used as a base catalyst.

17. The process of claim 1, wherein the catalyst composition comprises a molecular sieve.

18. The process of claim 17, wherein the catalyst comprises at least one of zeolite Y, zeolite REY, zeolite X, zeolite USY and zeolite REUSY.

19. The process of claim 1, wherein propylene is produced.

20. The process of claim 19, wherein the propylene selectivity is at least about 30%.

21. The process of claim 20, wherein the propylene selectivity is at least about 50%.

22. The process of claim 21, wherein the propylene selectivity is at least about 60%.

23. The process of claim 19, wherein light olefins are produced and the light olefin selectivity is at least about 50%.

24. The process of claim 23, wherein the light olefin selectivity is at least about 70%.

25. The process of claim 24, wherein the light olefin selectivity is at least about 80%.

26. The process of claim 20, wherein light olefins are produced and the light olefin selectivity is at least about 50%.

27. The process of claim 21, wherein light olefins are produced and the light olefin selectivity is at least about 70%.

28. The process of claim 23, wherein light olefins are produced and the light olefin selectivity is at least about 80%.

29. The process of claim 1, wherein the catalyst composition comprises a synthetic porous crystalline material comprising a framework of tetrahedral atoms bridged by oxygen atoms, the tetrahedral atom framework being defined by a unit cell with atomic coordinates in nanometers shown in Table 1, wherein each coordinate position may vary within ±0.05 nanometer.

30. The process of claim 1, wherein the synthetic porous crystalline material has an X-ray diffraction pattern including d-spacing and relative intensity values substantially as set forth in Table 2.

31. The process of claim 29, wherein the synthetic porous crystalline material has an X-ray diffraction pattern including d-spacing and relative intensity values substantially as set forth in Table 2.

32. The process of claim 1, wherein the synthetic porous crystalline material has a composition comprising the molar relationship X2O3:(n)YO2, wherein n is at least about 5, X is a trivalent element, and Y is a tetravalent element.

33. The process of claim 29, wherein the synthetic porous crystalline material has a composition comprising the molar relationship X2O3:(n)YO2, wherein n is at least about 5, X is a trivalent element, and Y is a tetravalent element.

34. The process of claim 30, wherein the synthetic porous crystalline material has a composition comprising the molar relationship X2O3:(n)YO2, wherein n is at least about 5, X is a trivalent element, and Y is a tetravalent element.

35. The process of claim 31, wherein the synthetic porous crystalline material has a composition comprising the molar relationship X2O3:(n)YO2, wherein n is at least about 5, X is a trivalent element, and Y is a tetravalent element.

36. The process recited in claim 35, wherein X is a trivalent element selected from the group consisting of boron, iron, indium, gallium, aluminum, and a combination thereof; and Y is a tetravalent element selected from the group consisting of silicon, tin, titanium, germanium, and a combination thereof.

37. The process recited in claim 36, wherein X comprises boron or aluminum and Y comprises silicon.

38. The process of claim 37, wherein X is aluminum.

39. The process of claim 1, wherein the catalyst composition also comprises a large pore molecular sieve having a pore size greater than 6 Angstrom.

40. The process of claim 39, wherein the large pore molecular sieve has a pore size greater than 7 Angstrom.

41. The process of claim 39, wherein the weight ratio of said synthetic porous crystalline material to the large pore molecular sieve is about 0.005 to about 50.

42. The process of claim 40, wherein the weight ratio of said synthetic porous crystalline material to the large pore molecular sieve is about 0.005 to about 50.

43. The process of claim 41, wherein the weight ratio of said synthetic porous crystalline material to the large pore molecular sieve is about 0.1 to about 1.0.

44. The process of claim 42, wherein the weight ratio of said synthetic porous crystalline material to the large pore molecular sieve is about 0.1 to about 1.0.

45. The process of claim 11, wherein the catalyst is metal-stabilized with copper.

46. The process of claim 1, wherein the catalyst composition comprises at least one of a zeolite and SAPO.

47. The process of claim 1, wherein at least part of the reaction zone is at a temperature of about 500°-600° C.

48. The process of claim 1, wherein the process total pressure is about 0.5 to about 10 atmospheres.

49. The process of claim 48, wherein the process total pressure is about 1 to about 3 atmospheres.

Description:

CROSS-REFERENCE TO RELATED APPLICATION(S)

[0001] The present application is related to (1) application Ser. No. (awaited) filed on Oct. 29, 2002, entitled “Aromatics Conversion with ITQ-13” by inventors John S. Buchanan et al. (attorney docket number 2002B145); (2) application Ser. No. 09/866,907 filed on May 29, 2001, entitled “Synthetic Porous Crystalline Material ITQ-13, Its Synthesis and Use” by inventors Girones et al. (attorney docket number P2001J030); and (3) provisional application Ser. No. 60/363,100 filed on Mar. 5, 2002 entitled “Catalytic Cracking with Zeolite ITQ-13” by inventor Corma (attorney docket number P2002J026). All of these applications are incorporated herein by reference.

BACKGROUND TO THE INVENTION

[0002] This invention relates to a process for catalytic cracking of hydrocarbon feedstocks to produce an enhanced yield of light (C2-C4) olefins and in particular an enhanced yield of propylene.

DESCRIPTION OF THE PRIOR ART

[0003] Catalytic cracking, and particularly fluid catalytic cracking (FCC), is routinely used to convert heavy hydrocarbon feedstocks to lighter products, such as gasoline and distillate range fractions. Conventional processes for catalytic cracking of heavy hydrocarbon feedstocks to gasoline and distillate fractions typically use a large pore molecular sieve, such as zeolite Y, as the primary cracking component. It is also well known to add a medium pore molecular sieve, such as ZSM-5 and ZSM-35, to the cracking catalyst composition to increase the octane number of the gasoline fraction (see U.S. Pat. No. 4,828,679).

[0004] In addition, it is known from, for example, U.S. Pat. No. 4,969,987 to employ medium pore molecular sieves, such as ZSM-5 and ZSM-12, to crack paraffinic and naphthenic naphthas to produce a light olefinic fraction rich in C4-C5 isoalkenes and a C6+ liquid fraction of enhanced octane value.

[0005] There is, however, an increasing need to enhance the yield of light olefins, especially propylene, in the product slate from catalytic cracking processes. Thus propylene is in high demand for a variety of commercial applications, particularly in the manufacture of polypropylene, isopropyl alcohol, propylene oxide, cumene, synthetic glycerol, isoprene, and oxo alcohols.

[0006] Co-pending U.S. patent application Ser. No. 09/866,907, filed May 29, 2001, describes a synthetic porous crystalline material, ITQ-13, which is a single crystalline phase material having a unique 3-dimensional channel system comprising three sets of channels, two defined by 10-membered rings of tetrahedrally coordinated atoms and the third by 9-membered rings of tetrahedrally coordinated atoms. Co-pending U.S. patent application Ser. No. 60/362,100, filed Mar. 5, 2002, describes a process for cracking hydrocarbons using a catalyst comprising ITQ-13.

SUMMARY OF THE INVENTION

[0007] According to one aspect of the present invention a catalytic cracking process comprises contacting, under catalytic cracking conditions, a feedstock comprising hydrocarbons having at least 5 carbon atoms with a catalyst composition comprising a synthetic porous crystalline material having a multi-dimensional channel system, at least a first parallel set of said channels comprising 9-member rings having a pore size of at least about 3.6 Angstroms. According to another aspect, a second set of channels comprises 10-member rings. Preferably, the catalyst channel system is 3-dimensional. A preferred hydrocarbon feed is naphtha or at least one of gas oil, vacuum gas oil and residual oil vacuum resid. Also preferably, the catalytic cracking process is a fluid catalytic cracking process.

[0008] According to a further aspect of the present invention, the at least first parallel set of channels has a pore size of at least about 4.0 Angstroms, more preferably at least about 4.2 Angstroms. In another aspect, the at least first parallel set of channels has a pore size less than or equal to about 5.0 Angstroms.

[0009] According to yet a further aspect of the invention, the catalyst can be metal-stabilized. Preferably, the catalyst is metal-stabilized with at least one of at least one metal of Group 2a, 3b, 4b, 7b, 8, 1b, 2b, 3a and 5a of The Periodic Table of the Elements. More preferably, the catalyst is metal-stabilized with at least one of copper, phosphorus, iron, silver, magnesium, lanthanum, zinc, aluminum, zirconium, manganese, and cerium. Even more preferably, the catalyst is metal-stabilized with at least one of copper and phosphorus. Most preferably, copper is used.

[0010] In one aspect of the present invention the catalyst composition is used as an additive catalyst. In another aspect, the catalyst composition is used as a base catalyst. In yet another aspect in accordance with the present invention, the catalyst composition comprises a molecular sieve. According to another aspect, the molecular sieve comprises at least one of zeolite Y, zeolite REY, zeolite X, zeolite USY and zeolite REUSY.

[0011] According to another aspect of the present invention, propylene is produced. Preferably, the propylene selectivity (moles of propylene per mole of C4 produced) is at least about 30%, more preferably at least about 50 %, most preferably at least about 60%. As used herein, propylene selectivity is defined as the ratio of propylene to total C1-C4 hydrocarbon products (weight basis).

[0012] According to yet another aspect of the present invention, light olefins (C3+C4) are produced and the light olefin selectivity is at least about 50%, preferably about 70%, more preferably about 80%. As used herein, light olefin selectivity is defined as the ratio of propylene and butylene to total C1-C4 hydrocarbon products (weight basis).

[0013] According to another aspect of the present invention, the catalyst composition comprises a synthetic porous crystalline material comprising a framework of tetrahedral atoms bridged by oxygen atoms, the tetrahedral atom framework being defined by a unit cell with atomic coordinates in nanometers shown in Table 1, wherein each coordinate position may vary within ±0.05 nanometer.

[0014] Preferably, the synthetic porous crystalline material has an X-ray diffraction pattern including d-spacing and relative intensity values substantially as set forth in Table 2 below.

[0015] In a further aspect of the invention, the catalyst composition also comprises a large pore molecular sieve having a pore size greater than 6 Angstroms, preferably greater than 7 Angstroms.

DESCRIPTION OF DRAWINGS

[0016] FIG. 1 is a non-limiting, schematic illustration of a unit cell of ITQ-13, a 9-member ring synthetic porous crystalline material in accordance with the present invention, showing the positions of the tetrahedral atoms.

[0017] FIG. 2 is a non-limiting schematic illustration of the 9-member ring channel system of ITQ-13, again showing the positions of the tetrahedral atoms.

[0018] FIGS. 3 and 4 are non-limiting, schematic illustrations, similar to FIG. 2, of the ten-ring channel systems of ITQ-13.

[0019] FIGS. 5-7 are X-ray powder diffraction patterns of the 9-member ring product of Example 6, as synthesized, after calcination and after insertion of aluminum, respectively.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0020] The particulars shown herein are by way of example and for purposes of illustrative discussion of the embodiments of the present invention only and are presented to provide what is believed to be the most useful and readily understood description of the principles and conceptual aspects of the present invention. In this regard, no attempt is made to show details of the present invention in more detail than is necessary for the fundamental understanding of the present invention, the description making apparent to those skilled in the art how the several forms of the present invention may be embodied in practice.

[0021] Unless otherwise stated, all percentages, parts, ratios, etc., are by weight. Unless otherwise stated, a reference to a compound or component includes the compound or component by itself, as well as in combination with other compounds or components, such as mixtures of compounds.

[0022] Further, when an amount, concentration, or other value or parameters is given as a list of upper preferable values and lower preferable values, this is to be understood as specifically disclosing all ranges formed from any pair of an upper preferred value and a lower preferred value, regardless whether ranges are separately disclosed.

[0023] The present invention provides a process for converting feedstock hydrocarbon compounds to product hydrocarbon compounds of lower molecular weight than the feedstock hydrocarbon compounds. In particular, the present invention provides a process for catalytically cracking a hydrocarbon feedstock having at least 5 carbon atoms to selectively produce C2 to C4 olefins, and in particular to selectively produce propylene. The process of the invention employs a catalyst composition comprising a synthetic porous crystalline material having a multi-dimensional channel system, at least a first parallel set of said channels comprising 9-member rings having a pore size of at least about 3.6 Angstroms. Preferably, the pore size of the 9-member rings is at least about 4.0 Angstroms. More preferably, the pore size of the 9-member rings is at least about 4.2 Angstroms. Also preferably, these rings have a pore size less than or equal to about 5.0 Angstroms. Preferably, the catalyst composition comprises a synthetic porous crystalline material having a multi-dimensional channel system, at least a first parallel set of said channels comprising 9-member rings having a pore size greater than about 3.6 Angstroms and at least a second set of channels comprising at least 10-member rings. The catalyst composition preferably comprises at least one of a zeolite or SAPO.

[0024] It should be understood throughout this specification that a reference to a single dimension of a pore describes its smallest dimension. Techniques for determining how many members there are in a ring (e.g., 9 members), as well as pore size are well known in the art. By way of non-limiting example, Atlas of Zeolite Framework Types, 5th edition (2001), Ch. Baelocher, W. M. Meier, and D. H. Olson, which is incorporated herein by reference, describes such techniques.

[0025] According to a preferred aspect of the present invention, the catalyst comprises ITQ-13, which is a synthetic porous crystalline material comprising a framework of tetrahedral atoms bridged by oxygen atoms, the tetrahedral atom framework being defined by a unit cell with atomic coordinates in nanometers shown in Table 1, wherein each coordinate position may vary within ±0.05 nanometer. According to another aspect in accordance with the present invention, the catalyst composition comprises synthetic porous crystalline material ITQ-13 and, optionally, a large pore molecular sieve having a pore size greater than 6 Angstroms. In yet a further aspect in accordance with the present invention, the large pore molecular sieve has a pore size greater than 7 Angstroms.

[0026] The synthetic porous crystalline material ITQ-13 is described in our co-pending U.S. patent application Ser. No. 09/866,907, incorporated herein by reference, and is a single crystalline phase that has a unique 3-dimensional channel system comprising three sets of channels. In particular, ITQ-13 comprises a first set of generally parallel channels each of which is defined by a 10-membered ring of tetrahedrally coordinated atoms, a second set of generally parallel channels which are also defined by 10-membered rings of tetrahedrally coordinated atoms and which are perpendicular to and intersect with the channels of the first set, and a third set of generally parallel channels which intersect with the channels of said first and second sets and each of which is defined by a 9-membered ring of tetrahedrally coordinated atoms. The first set of 10-ring channels each has cross-sectional dimensions of about 4.8 Angstrom by about 5.5 Angstrom, whereas the second set of 10-ring channels each has cross-sectional dimensions of about 5.0 Angstrom by about 5.7 Angstrom. The third set of 9-ring channels each has cross-sectional dimensions of about 4.0 Angstrom by about 4.9 Angstrom.

[0027] The structure of ITQ-13 may be defined by its unit cell, which is the smallest structural unit containing all the structural elements of the material. Table 1 lists the positions of each tetrahedral atom in the unit cell in nanometers; each tetrahedral atom is bonded to an oxygen atom that is also bonded to an adjacent tetrahedral atom. Since the tetrahedral atoms may move about due to other crystal forces (presence of inorganic or organic species, for example), a range of ±0.05 nm is implied for each coordinate position. 1

TABLE 1
T10.6260.1590.794
T20.1510.1510.478
T30.3850.2870.333
T40.6260.1580.487
T50.1530.1490.781
T60.3830.2501.993
T70.4730.1530.071
T80.4690.0001.509
T90.4660.0001.820
T100.6260.9790.794
T111.1000.9870.478
T120.8670.8510.333
T130.6260.9800.487
T141.0990.9890.781
T150.8690.8881.993
T160.7780.9850.071
T170.7830.0001.509
T180.7850.0001.820
T190.1510.9870.478
T200.3850.8510.333
T210.1530.9890.781
T220.3830.8881.993
T230.4730.9850.071
T241.1000.1510.478
T250.8670.2870.333
T261.0990.1490.781
T270.8690.2501.993
T280.7780.1530.071
T290.6260.7281.895
T300.1510.7201.579
T310.3850.8561.433
T320.6260.7271.588
T330.1530.7181.882
T340.3830.8190.893
T350.4730.7221.171
T360.4690.5690.409
T370.4660.5690.719
T380.6260.4101.895
T391.1000.4181.579
T400.8670.2821.433
T410.6260.4111.588
T421.0990.4201.882
T430.8690.3190.893
T440.7780.4161.171
T450.7830.5690.409
T460.7850.5690.719
T470.1510.4181.579
T480.3850.2821.433
T490.1530.4201.882
T500.3830.3190.893
T510.4730.4161.171
T521.1000.7201.579
T530.8670.8561.433
T541.0990.7181.882
T550.8690.8190.893
T560.7780.7221.171

[0028] ITQ-13 can be prepared in essentially pure form with little or no detectable impurity crystal phases and has an X-ray diffraction pattern which is distinguished from the patterns of other known as-synthesized or thermally treated crystalline materials by the lines listed in Table 2 below. 2

d(Å)Relative Intensities (I)
12.46 ± 0.2 w-vs
10.97 ± 0.2 m-vs
10.12 ± 0.2 vw-w 
8.25 ± 0.2 vw
7.87 ± 0.2 w-vs
5.50 ± 0.15w-m
5.45 ± 0.15vw
5.32 ± 0.15vw-w 
4.70 ± 0.15vw
4.22 ± 0.15w-m
4.18 ± 0.15vw-w 
4.14 ± 0.15w
3.97 ± 0.1 w
3.90 ± 0.1 w
3.86 ± 0.1 vw-m 
3.73 ± 0.1 m-vs
3.66 ± 0.1 m-vs

[0029] These X-ray diffraction data were collected with a Scintag diffraction system, equipped with a germanium solid state detector, using copper K-alpha radiation. The diffraction data were recorded by step-scanning at 0.02 degrees of two-theta, where theta is the Bragg angle, and a counting time of 10 seconds for each step. The interplanar spacings, d's, were calculated in Angstrom units, and the relative intensities of the lines, I/Io is one-hundredth of the intensity of the strongest line, above background, were derived with the use of a profile fitting routine (or second derivative algorithm). The intensities are uncorrected for Lorentz and polarization effects. The relative intensities are given in terms of the symbols vs=very strong (80-100), s=strong (60-80), m=medium (40-60), w=weak (20-40), and vw=very weak (0-20). It should be understood that diffraction data listed for this sample as single lines may consist of multiple overlapping lines which under certain conditions, such as differences in crystallographic changes, may appear as resolved or partially resolved lines. Typically, crystallographic changes can include minor changes in unit cell parameters and/or a change in crystal symmetry, without a change in the structure. These minor effects, including changes in relative intensities, can also occur as a result of differences in cation content, framework composition, nature and degree of pore filling, crystal size and shape, preferred orientation and thermal and/or hydrothermnal history.

[0030] ITQ-13 has a composition involving the molar relationship:

X2O3:(n)YO2,

[0031] wherein X is a trivalent element, such as aluminum, boron, iron, indium, and/or gallium, preferably boron; Y is a tetravalent element such as silicon, tin, titanium and/or germanium, preferably silicon; and n is at least about 5, such as about 5 to infinity, and usually from about 40 to about infinity. It will be appreciated from the permitted values for n that ITQ-13 can be synthesized in totally siliceous form in which the trivalent element X is absent or essentially absent.

[0032] Processes for synthesizing ITQ-13 employ fluorides, in particular HF, as a mineralizing agent and hence, in its as-synthesized form, ITQ-13 has a formula, on an anhydrous basis and in terms of moles of oxides per n moles of YO2, as follows:

(0.2-0.4)R:X2O3:(n)YO2L(0.4-0.8)F

[0033] wherein R is an organic moiety. The R and F components, which are associated with the material as a result of their presence during crystallization, are easily removed by post-crystallization methods hereinafter more particularly described.

[0034] To the extent desired and depending on the X2O3/YO2 molar ratio of the material, any cations in the as-synthesized ITQ-13 can be replaced in accordance with techniques well known in the art, at least in part, by ion exchange with other cations. Preferred replacing cations include metal ions, hydrogen ions, hydrogen precursor, e.g., ammonium ions and mixtures thereof. Particularly preferred cations are those which tailor the catalytic activity for certain hydrocarbon conversion reactions. These include hydrogen, rare earth metals and metals of Groups IIA, IIIA, IVA, VA, IB, IIB, IIIB, IVB, VB, VIB, VIIB and VIII of the Periodic Table of the Elements. For light olefin selectivity, copper and phosphorus are most preferred.

[0035] The as-synthesized ITQ-13 may be subjected to treatment to remove part or all of any organic constituent used in its synthesis. This is conveniently effected by thermal treatment in which the as-synthesized material is heated at a temperature of at least about 370° C. for at least 1 minute and generally not longer than 20 hours. While subatmospheric pressure can be employed for the thermal treatment, atmospheric pressure is desired for reasons of convenience. The thermal treatment can be performed at a temperature up to about 925° C. The thermally treated product, especially in its metal, hydrogen and ammonium forms, is particularly useful in the catalysis of certain organic, e.g., hydrocarbon, conversion reactions.

[0036] Prior to use in the process of the invention, the ITQ-13 is preferably dehydrated, at least partially. This can be done by heating to a temperature in the range of 200° C. to about 370° C. in an atmosphere such as air, nitrogen, etc., and at atmospheric, subatmospheric or superatmospheric pressures for between 30 minutes and 48 hours. Dehydration can also be performed at room temperature merely by placing the ITQ-13 in a vacuum, but a longer time is required to obtain a sufficient amount of dehydration.

[0037] The silicate and borosilicate forms of ITQ-13 can be prepared from a reaction mixture containing sources of water, optionally an oxide of boron, an oxide of tetravalent element Y, e.g., silicon, a directing agent (R) as described below and fluoride ions, said reaction mixture having a composition, in terms of mole ratios of oxides, within the following ranges: 3

ReactantsUsefulPreferred
YO2/B2O3at least 5At least 40
H2O/YO2 2-50 5-20
OH/YO20.05-0.70.2-0.4
F/YO20.1-1 0.4-0.8
R/YO20.05-0.70.2-0.4

[0038] The organic directing agent R used herein is the hexamethonium [hexamethylenebis(trimethylammonium)] dication and preferably is hexamethonium dihydroxide. Hexamethonium dihydroxide can readily be prepared by anion exchange of commercially available hexamethonium bromide.

[0039] Crystallization of ITQ-13 can be carried out at either static or stirred conditions in a suitable reactor vessel, such as for example, polypropylene jars or Teflon®-lined or stainless steel autoclaves, at a temperature of about 120° C. to about 160° C. for a time sufficient for crystallization to occur at the temperature used, e.g., from about 12 hours to about 30 days. Thereafter, the crystals are separated from the liquid and recovered.

[0040] It should be realized that the reaction mixture components can be supplied by more than one source. The reaction mixture can be prepared either batch-wise or continuously. Crystal size and crystallization time of the new crystalline material will vary with the nature of the reaction mixture employed and the crystallization conditions.

[0041] Synthesis of ITQ-13 may be facilitated by the presence of at least 0.01 percent, preferably 0.10 percent and still more preferably 1 percent, seed crystals (based on total weight) of crystalline product.

[0042] The ITQ-13 used in the process of the invention is preferably an aluminosilicate or boroaluminosilicate and more preferably has a silica to alumina molar ratio of less than about 1000. Aluminosilicate ITQ-13 can readily be produced from the silicate and borosilicate forms by post-synthesis methods well-known in the art, for example by ion exchange of the borosilicate material with a source of aluminum ions.

[0043] Particularly when employed to crack heavy hydrocarbons feedstocks, such as those having an initial boiling point of about 200° C., the catalyst composition used in the process of the invention preferably comprises a large pore molecular sieve having a pore size greater than 6 Angstrom, and preferably greater than 7 Angstrom, in addition to the 9-member ring catalyst composition of the present invention. Typically, where the catalyst contains a large pore molecular sieve, the weight ratio of the 9-member ring catalyst to the large pore molecular sieve is about 0.005 to 50, preferably about 0.1 to 1.0.

[0044] The large-pore cracking component may be any conventional molecular sieve having cracking activity and a pore size greater than 6 Angstrom including zeolite X (U.S. Pat. No. 2,882,442); REX; zeolite Y (U.S. Pat. No. 3,130,007); Ultrastable Y zeolite (USY) (U.S. Pat. No. 3,449,070); Rare Earth exchanged Y (REY) (U.S. Pat. No. 4,415,438); Rare Earth exchanged USY (REUSY); Dealuminated Y (DeAl Y) (U.S. Pat. No. 3,442,792; U.S. Pat. No. 4,331,694); Ultrahydrophobic Y (UHPY) (U.S. Pat. No. 4,401,556); and/or dealuminated silicon-enriched zeolites, e.g., LZ-210 (U.S. Pat. No. 4,678,765). Zeolite ZK-5 (U.S. Pat. No. 3,247,195); zeolite ZK-4 (U.S. Pat. No. 3,314,752); ZSM-20 (U.S. Pat. No. 3,972,983); zeolite Beta (U.S. Pat. No. 3,308,069) and zeolite L (U.S. Pat. Nos. 3,216,789 and 4,701,315), as well as naturally occurring zeolites such as faujasite, mordenite and the like may also be used. These materials may be subjected to conventional treatments, such as impregnation or ion exchange with rare earths to increase stability. The preferred large pore molecular sieve of those listed above is a zeolite Y, more preferably an REY, USY or REUSY.

[0045] Other suitable large-pore crystalline molecular sieves include pillared silicates and/or clays; aluminophosphates, e.g., ALPO4-5, ALPO4-8, VPI-5; silicoaluminophosphates, e.g., SAPO-5, SAPO-37, SAPO-31, SAPO-40; and other metal aluminophosphates. These are variously described in U.S. Pat. Nos. 4,310,440; 4,440,871; 4,554,143; 4,567,029; 4,666,875; 4,742,033; 4,880,611; 4,859,314; and 4,791,083.

[0046] The cracking catalyst will also normally contain one or more matrix or binder materials that are resistant to the temperatures and other conditions e.g., mechanical attrition, which occur during cracking. Where the cracking catalyst contains a large pore molecular sieve in addition to the 9-member ring catalyst composition, the matrix material may be used to combine both molecular sieves in each catalyst particle. Alternatively, the same or different matrix materials can be used to produce separate particles containing the large pore molecular sieve and the 9-member ring catalyst composition respectively. In the latter case, the different catalyst components can be arranged in separate catalyst beds.

[0047] The matrix may fulfill both physical and catalytic functions. Matrix materials include active or inactive inorganic materials such as clays, and/or metal oxides such as alumina or silica, titania, zirconia, or magnesia. The metal oxide may be in the form of a sol or a gelatinous precipitate or gel.

[0048] Naturally occurring clays that can be employed in the catalyst include the montmorillonite and kaolin families which include the subbentonites, and the kaolins commonly known as Dixie, McNamee, Georgia and Florida clays or others in which the main mineral constituent is halloysite, kaolinite, dickite, nacrite or anauxite. Such clays can be used in the raw state as originally mined or initially subjected to calcination, acid treatment or chemical modification.

[0049] In addition to the foregoing materials, catalyst can include a porous matrix material such as silica-alumina, silica-magnesia, silica-zirconia, silica-thoria, silica-beryllia, silica-titania, as well as ternary materials such as silica-alumina-thoria, silica-alumina-zirconia, silica-alumina-magnesia, silica-magnesia-zirconia. The matrix can be in the form of a cogel. A mixture of these components can also be used.

[0050] In general, the relative proportions of molecular sieve component(s) and inorganic oxide matrix vary widely, with the molecular sieve content ranging from about 1 to about 90 percent by weight, and more usually from about 2 to about 80 weight percent of the composite.

[0051] The feedstock employed in the process of the invention comprises one or more hydrocarbons having at least 5 carbon atoms.

[0052] In one aspect, the feedstock comprises a naphtha. Typically such feedstocks have a boiling range of about 25° C. to about 225° C. and preferably a boiling range of 25° C. to 125° C. The naphtha can be a thermally cracked or a catalytically cracked naphtha. Such streams can be derived from any appropriate source, for example, they can be derived from the fluid catalytic cracking (FCC) of gas oils and resids, or they can be derived from delayed or fluid coking of resids. It is preferred that the naphtha streams be derived from the fluid catalytic cracking of gas oils and resids. Such naphthas are typically rich in olefins and/or diolefins and relatively lean in paraffins.

[0053] The feedstock could, alternatively, comprise a hydrocarbon mixture having an initial boiling point of about 200° C. The hydrocarbon feedstock to be cracked may include, in whole or in part, a gas oil (e.g., light, medium, or heavy gas oil) having an initial boiling point above 200° C., a 50 % point of at least 260° C. and an end point of at least 315° C. The feedstock may also include vacuum gas oils, thermal oils, residual oils, gas oil, vacuum gas oil, residual oil vacuum resid, cycle stocks, whole top crudes, tar sand oils, shale oils, synthetic fuels, heavy hydrocarbon fractions derived from the destructive hydrogenation of coal, tar, pitches, asphalts, hydrotreated feedstocks derived from any of the foregoing, and the like. As will be recognized, the distillation of higher boiling petroleum fractions above about 400° C. must be carried out under vacuum in order to avoid thermal cracking. The boiling temperatures utilized herein are expressed for convenience in terms of the boiling point corrected to atmospheric pressure. Resids or deeper cut gas oils with high metals contents can also be cracked using the process of the invention. Naphthas and at least one of gas oil, vacuum gas oil, residual oil vacuum resid are preferred feedstocks.

[0054] The catalytic cracking process of the invention can operate at temperatures from about 200° C. to about 870° C. under reduced, atmospheric or superatmospheric pressure. By way of non-limiting example, the process total pressure could be about 0.5 to about 10 atmospheres, preferably about 1 to about 3 atmospheres. The catalytic process can be either fixed bed, moving bed or fluidized bed and the hydrocarbon flow may be either concurrent or countercurrent to the catalyst flow. The process of the invention is particularly applicable to the Fluid Catalytic Cracking (FCC) or moving bed processes such as the Thermofor Catalytic Cracking (TCC) processes.

[0055] The TCC process is a moving bed process wherein the catalyst is in the shape of pellets or beads having an average particle size of about one sixty-fourth to one-fourth inch. Active, hot catalyst beads progress downwardly cocurrent with a hydrocarbon charge stock through a cracking reaction zone. The hydrocarbon products are separated from the coked catalyst and recovered, whereas the coked catalyst is removed from the lower end of the reaction zone and regenerated. Typically TCC conversion conditions include an average reactor temperature of about 450° C. to about 510° C.; catalyst/oil volume ratio of about 2 to about 7; reactor space velocity of about 1 to about 2.5 vol./hr./vol.; and recycle to fresh feed ratio of 0 to about 0.5 (volume).

[0056] The process of the invention is particularly applicable to fluid catalytic cracking (FCC), in which the cracking catalyst is typically a fine powder with a particle size of about 10 to 200 microns. This powder is generally suspended in the feed and propelled upward in a reaction zone. A relatively heavy hydrocarbon feedstock, e.g., a gas oil, is admixed with the cracking catalyst to provide a fluidized suspension and cracked in an elongated reactor, or riser, at elevated temperatures to provide a mixture of lighter hydrocarbon products. The gaseous reaction products and spent catalyst are discharged from the riser into a separator, e.g., a cyclone unit, located within the upper section of an enclosed stripping vessel, or stripper, with the reaction products being conveyed to a product recovery zone and the spent catalyst entering a dense catalyst bed within the lower section of the stripper. In order to remove entrained hydrocarbons from the spent catalyst prior to conveying the latter to a catalyst regenerator unit, an inert stripping gas, e.g., steam, is passed through the catalyst bed where it desorbs such hydrocarbons conveying them to the product recovery zone. The fluidizable catalyst is continuously circulated between the riser and the regenerator and serves to transfer heat from the latter to the former thereby supplying the thermal needs of the cracking reaction which is endothermnic.

[0057] Typically, FCC conversion conditions include a riser top temperature of about 500° C. to about 650° C., preferably from about 500° C. to about 600° C., and most preferably from about 500° C. to about 550° C.; catalyst/oil weight ratio of about 3 to about 12, preferably about 4 to about 11, and most preferably about 5 to about 10; and catalyst residence time of about 0.5 to about 15 seconds, preferably about 1 to about 10 seconds.

[0058] The invention will now be more particularly described with reference to the following Examples:

EXAMPLE 1

[0059] A 9-member ring catalyst composition, Borosilicate ITQ-13, was synthesized from a gel having the following molar composition:

1 SiO2: 0.01 B2O3: 0.29 R(OH)2: 0.64 HF : 7 H2O

[0060] where R(OH)2 is hexamethonium dihydroxide and 4 wt % of the SiO2 was added as ITQ-13 seeds to accelerate the crystallization. The hexamethonium dihydroxide employed in the gel was prepared by direct anionic exchange of commercially available hexamethonium dibromide using a resin, Amberlite IRN-78, as hydroxide source.

[0061] The synthesis gel was prepared by hydrolyzing 13.87 g of tetraethyloethosilicate (TEOS) in 62.18 g of a 0.006M hexamethonium dihydroxide solution containing 0.083 g of boric acid. The hydrolysis was effected under continuous mechanical stirring at 200 rpm, until the ethanol and an appropriate amount of water were evaporated to yield the above gel reaction mixture. After the hydrolysis step, a suspension of 0.16 g of as-synthesized ITQ-13 in 3.2 g of water was added as seeds and then a solution of 1.78 g of HF (48 wt % in water) and 1 g of water were slowly added to produce the required reaction mixture. The reaction mixture was mechanically and finally manually stirred until a homogeneous gel was formed. The resulting gel was very thick as a consequence of the small amount of water present. The gel was autoclaved at 135° C. for 21 days under continuous tumbling at 60 rpm. The pH of the final gel (prior of filtration) was 6.5-7.5. The solid was recovered by filtration, washed with distilled water and dried at 100° C., overnight. The occluded hexamethonium and fluoride ions were removed from the product by heating the product from room temperature to 540° C. at 1° C./min under N2 flow (60 ml/mm). The temperature was kept at 540° C. under N2 for 3 hours and then the flow was switched to air and the temperature kept at 540° C. for a further 3 hours in order to burn off the remaining organic. X-ray analysis showed the calcined product to be ITQ-13 containing some ZSM-50 impurity, whereas boron analysis indicated the Si/B atomic ratio of the final solid to be about 60.

[0062] Aluminum-containing ITQ-13 was prepared using ion exchange by suspending, under stirring, 0.74 g of the calcined B-ITQ-13 in 10.5 g of an aqueous Al(NO3)3 solution containing 8 wt % Al(NO3)3 and then transferring the resultant suspension to an autoclave, where the suspension was heated at 135° C. for 3 days under continuous stirring at 60 rpm. The resulting solid was filtered, washed with distilled water until the water was at neutral pH and dried at 1 00° C., overnight. Chemical analysis indicated the product to have a Si/Al atomic ratio of 80 and a Si/B atomic ratio greater than 500.

Example 2

[0063] Five separate catalysts were prepared from (a) the aluminum-containing ITQ-13 from Example 1, (b) ZSM-5, (c) ferrierite (FER) (d) a commercially available USY having a unit cell size of 2.432 nm and (e) a commercially available USY having a unit cell size of 2.426 nm. The properties of the various zeolites employed were as follows: 4

USYUSY
ZeoliteZSM-5ITQ-13FER2.432 nm2.426 nm
Surface Area, m2/g385354280641 551
Crystal Size, micron0.5-10.1-0.31-30.5  0.5
Si/Al atomic area438060 19*62*
Bronsted Activity
(μmol Py/g)
T = 523° K.4018217714 
T = 623° K.261214453
T = 673° K.755281
Lewis Activity
(μmol Py/g)
T = 523° K.682 910 
T = 623° K.561 87
T = 673° K.561 74
*= after steaming

[0064] Each of catalysts (a) to (c) contained 0.5 gm of the zeolite diluted with 2.5 gm of inert silica, whereas each of catalysts (d) and (e) contained 1.20 gm of USY diluted with 0.30 gm of inert silica.

EXAMPLE 3

[0065] The catalysts containing ITQ-13 and ZSM-5 produced in Example 2 were used to crack hexene-1 and 4-methylpentene-1 in a conventional Microactivity Test Unit (MAT) at 500° C., 60 seconds time on stream, and catalyst to oil ratios (w/w) of 0.3-0.7. Gases were analyzed by gas chromatography in a HP 5890 Chromatograph with a two-column system in series using argon as the camrer gas. Hydrogen, nitrogen and methane were separated in a 15 m long, 0.53 mm internal diameter molecular sieve 5A column and thermal conductivity detector. C2 to C5 hydrocarbons were separated in a 50 m long, 0.53 mm internal diameter alumina plot column and flame ionization detector. Liquids were analyzed in a Varian 3400 with a 100 m long, 0.25 mm internal diameter Petrocol DH column.

[0066] The results of cracking the two olefins are shown below in Tables 3 and 4. These have been estimated at constant conversion by fitting the individual component analyses over the range of catalyst/oil ratios used in the experiments to suitable polynomials and interpolated at a central point. It will be seen from Tables 3 and 4 that the 9-member ring catalyst composition (containing ITQ-13) provided much higher yields of propylene (20.86 wt % for hexene-1 and 19.7 wt % for 4-methylpentene-1) than the catalyst containing ZSM-5 (11.91 wt % for hexene-1 and 11.21 wt % for 4-methylpentene-1). Moreover the 9-member ring catalyst composition provided much higher ratios of propylene to propane (35 for hexene-1 and 22 for 4-methylpentene-1) than the catalyst containing ZSM-5 (6 for hexene-1 and 7 for 4-methylpentene-1). 5

TABLE 3
CATALYSTZSM-5ITQ-13
FeedHexane-1Hexene-1
Cat/Oil0.050.09
Conversion, wt %5454
Liquids, wt %25.8118.37
Gases, wt %27.8534.81
Coke, wt %0.350.53
H2, wt %0.010.003
C1, wt %0.040.06
C2, wt %0.130.14
C2═, wt %2.672.43
C3, wt %1.700.60
C3═, wt %11.9120.86
iC4, wt %1.540.50
nC4, wt %0.730.20
t2C4═, wt %1.812.14
IC4═, wt %1.942.07
iC4═, wt %3.883.86
c2C4═, wt %1.481.74

[0067] 6

TABLE 4
CATALYSTZSM-5ITQ-13
Feed4-methylpentene-14-methylpentene-1
Cat/Oil0.050.09
Conversion, wt %9.0049.00
Liquids, wt %21.8416.03
Gases, wt %26.8232.31
Coke, wt %0.340.67
H2, wt %0.010.009
C1, wt %0.050.10
C2, wt %0.070.06
C2═, wt %2.332.02
C3, wt %1.650.88
C3═, wt %11.2119.17
iC4, wt %1.470.60
nC4, wt %0.720.18
t2C4═, wt %1.842.03
IC4═, wt %1.951.94
iC4═, wt %3.953.76
c2C4═, wt %1.551.66

EXAMPLE 4

[0068] The use of the ITQ-13, ZSM-5 and FER catalysts of Example 2 as additives to the USY cracking catalysts of Example 2 in the cracking of a vacuum gas oil were studied in a similar MAT unit to that used in Example 3. The USY and additive catalysts were placed in separate beds. The top bed contained the

[0069] USY zeolite and the bottom bed contained the zeolite additive diluted in 1.10 gm of silica. The properties of the vacuum gas oil used are given in Table 5. 7

TABLE 5
Density (15° C.) g/cc0.917
Aniline Point (° C.)79.2
S (wt %)1.65
N, ppm1261
Na, ppm0.18
Cu, PPM<0.1
Fe, ppm0.3
Ni, ppm0.2
V, ppm0.4
ASTM D-1 160 (° C.)
 5%319
10%352
30%414
50%436
70%459
90%512

[0070] The results of the tests are shown in Tables 6 to 9 below. FIGS. 4 and 5 summarize the overall product make with the different USY catalysts, both alone and with the various additive catalysts, whereas Tables 8 and 9 summarize the results of analysis of the gasoline fractions obtained in each test. In the Tables, the first data column shows the results with the USY alone, whereas the data in the columns under the additive zeolites show the results when the additives were used. The percent of additive used corresponds to the weight of additive per 100 g USY zeolite. The catalyst/oil ratios are based on USY only. Estimates were made at constant 75 wt % conversion in the manner described above. 8

TABLE 6
CATALYSTUSY (2.432 nm)ZSM-5 (20%)ITQ-13 (20%)
Cat/Oil0.690.480.50
Gasoline, wt %41.9534.5736.82
Diesel, wt %14.5611.7712.61
Gases, wt %12.5321.8318.69
Coke, wt %1.461.821.38
Gas Yields, wt %
H20.070.03-0.03
C10.410.190.53
C2═0.801.591.18
C31.193.192.14
C3═2.325.174.45
iC43.884.824.46
nC40.891.811.41
t2C4═0.671.000.80
IC4═0.850.821.03
iC4═0.822.021.93
c2C4═0.630.970.63
Butene/Butane ratio0.620.720.75
Propylene/Propane1.951.622.08
ratio

[0071] 9

TABLE 7
USYZSM-5ITQ-13
CATALYST(2.426 nm)(20%)(20%)FER (20%)
Cat/Oil1.130.741.101.49
Gasoline, wt %39.2334.3637.8738.53
Diesel, wt %13.1012.0413.0813.19
Gases, wt %15.6422.0517.5316.46
Coke, wt %2.031.551.521.32
Gas Yields, wt %
H20.030.040.030.04
C10.630.570.290.34
C20.590.580.260.23
C2═1.001.810.851.17
C31.472.401.041.33
C3═3.415.655.153.99
iC44.613.883.664.34
nC41.041.210.941.03
t2C4═0.921.021.090.97
IC4═0.951.270.581.21
iC4═1.132.412.021.40
c2C4═0.771.071.180.80
Butene/Butane0.671.131.060.82
Propylene/Propane2.322.354.953.00

[0072] 10

TABLE 8
BASE CATALYSTUSY 2.432 nm +USY 2.432 nm +
CATALYST(USY 2.432 nm)20% ZSM-520% ITQ-13
n-Paraffins4.24.65.1
i-Paraffins26.421.323.4
Olefins9.16.17.0
Naphthenes12.09.711.0
Aromatics48.358.253.5
RON8788.588.2
MON83.184.783.8
Isoamylenes0.580.800.83

[0073] 11

TABLE 9
BASE CATALYSTUSY 2.426 nm +USY 2.426 nm +
CATALYST(USY 2.426 nm)20% ZSM-520% ITQ-13
n-Paraffins4.04.84.9
i-Paraffins22.218.520.5
Olefins8.96.58.3
Naphthenes11.69.29.8
Aromatics53.461.045.6
RON87.489.288.2
MON83.184.783.7
Isoamylenes0.450.600.81

[0074] It can be seen from Tables 6 and 7 that the 9-member ring catalyst composition in accordance with the present invention provides much lower yields of propane and butane than the catalysts containing ZSM-5 and FER, so that the propylene/propane ratio and the butene/butane ratio are higher with the 9-member ring catalyst composition than for the ZSM-5 and FER catalysts. Moreover, it can be seen from Tables 8 and 9 that addition of the 9-member ring catalyst composition additive to the USY cracking catalysts gave an increase in the octane number (both RON and MON) of the gasoline produced, although this increase was somewhat less than that obtained with the ZSM-5 additive.

EXAMPLE 5

[0075] To illustrate the effectiveness of 9-member ring catalyst in accordance with the present invention as additive for a fluid catalytic cracker, back-to-back experiments were carried out comparing a 9-member ring catalyst composition in accordance with the present invention to ZSM-5. The ZSM-5 was OlefinsMax. These experiment were carried out in a fixed fluidized bed reactor with vacuum gas oil (VGO) gas feed. In this series of experiments, OlefinsMax was steamed at 1500° F. for 16 hours to simulate commercial equilibration. The 9-member ring catalyst composition was ITQ-13, which was tested fresh.

[0076] The propylene selectivity for the ITQ-13 catalyst was 15% higher than that of the OlefinsMax catalyst. Its relative activity was also high at 1.4. This meant that the inventive catalyst was 40% more active than the OlefinsMax catalyst.

[0077] In addition to being active and selective, the ITQ-13 catalyst could also be stabilized. In bench unit testing with a 50/50 blend of hexane and hexane model compounds, copper modified ITQ-13 showed 35-42 weight % C4 conversion. This was a 35-50% improvement in catalyst activity as compared to untreated catalyst, which was steamed under nominally identical conditions (1400° F. for 2 hours). Further, the selectivity of the stabilized catalyst was significantly higher than that of the untreated catalyst.

EXAMPLE 6

[0078] To a perfluoroalkoxy-Teflon (PFA) bottle were added 300 grams Syton HT-50 silica (Aldrich), 3.09 grams of boric acid, 78.05 grams of 54.9 weight % of hexamethonium hydroxide solution, 93.9 grams of N,N,N′,N′-tetramethylhexane-1,6-diamine, 109.4 grams of 48 weight % HF, and 6.01 grams of ITQ-13 seeds. The bottle was shaken for 30-minutes. The pH was found to be 7.3. The bottle was placed into a 2 liter autoclave and heated at 1° C. per minute to 135° C, and held at 135° C. for 21 days. At the end of this time, the pH was found to be 7.1. The solid was filtered, washed copiously with water and dried to constant weight at 80° C. The yield was 151.9 grams. An X-ray powder diffraction pattern for the as-synthesized 9-member ring zeolite is shown in FIG. 5.

[0079] The as-synthesized material was calcined as a thin layer (˜1 gram per square centimeter) by ramping under N2, 2° C. per minute, to 230° C., holding for 2 hours, ramping at 2° C. per minute to 540° C. and holding for 8 hours. The gas was then switched to dry air, and the sample held 8 hours at 540° C., then cooled under dry air. An X-ray powder diffraction pattern for the calcined 9-member ring zeolite is shown in FIG. 6.

[0080] The calcined material was converted from the boron to the aluminum form by mixing 45 grams calcined ITQ-13, 98.3 grams Al(NO3)3.H2O. and 540 grams of H2O in a PFA bottle. The bottle was placed in a 2 liter autoclave and heated at 1° C. per minute to 135° C. and held at that temperature for 3 days. The product was filtered, washed with H2O until the washings had a pH>5, then dried to constant weight at 80° C. The yield was 43 grams. An X-ray powder diffraction pattern for the 9-member ring zeolite after aluminum insertion is shown in FIG. 7.

EXAMPLE 7

[0081] ITQ-13 crystals (powder) were pelletized into 40-60 mesh granules using the conventional press-and-sieve technique. The catalyst was loaded into a fixed-bed stainless steel microreactor and was activated in flowing nitrogen at 550° C. for 30 minutes before a 50:50 mixed 1-hexene and n-hexane feed was introduced over the catalyst using a micro syringe pump. The reactor pressure was 15 psig. The reactor effluent was analyzed with an on-line Gas Chromatograph equipped with a FID detector, at fixed on-stream feed intervals. The feed rate and the weight of catalyst loading (WHSV) were adjusted to obtain comparable initial feed conversion.

[0082] The results (shown in Table 10 below) show that the 9-member ring catalyst composition has notably stable on-stream catalytic activity, with a conversion to C4 products of about 42%. The propylene selectivity is attractive, at about 65%, and the propylene/propane ratio is around 20.

[0083] There was some reason to believe that the sample of ITQ-13 used in this example contained about 1.7 wt % ZSM-50 impurity. Applicants tested a catalyst consisting of 5% ZSM-50 in alumina for comparison. The ZSM-50 level in this reference catalyst is about 3 times higher than the estimated amount in the ITQ-13 sample, so the WHSV for the reference catalyst was tripled to 780 hr−1. The reference catalyst showed about 42% conversion after the first minute on stream, but with low (49%) selectivity to propylene. Conversion dropped rapidly, to 37% after 2 minutes and 23% after 4 minutes. Thus the activity of this ITQ-13 sample could not be attributed solely to 1-2 wt % ZSM-50 impurities. 12

TABLE 10
ITQ-13 WHSV 260 hr−1
Time, minutes3691315
g feed/g catalyst13263956.3365
C4 conversion, %42.5542.4342.4142.3642.17
Product yield, wt %
C1 + C20.390.370.370.40.38
C31.611.421.391.451.26
C23.423.293.253.313.22
C326.5927.3127.7127.427.78
C4's0.430.350.30.310.28
C4's10.119.699.399.499.25
Total C442.5542.4342.4142.3642.17
Selectivity, wt %
C1 + C20.920.870.870.940.90
C33.783.353.283.422.99
C28.047.757.667.817.64
C362.4964.3665.3464.6865.88
C4's1.010.820.710.730.66
C4's23.7622.8422.1422.4021.94