Chemistry of inorganic compounds – Zeolite – Structure defined x-ray diffraction pattern
Reexamination Certificate
2002-08-01
2003-05-27
Sample, David (Department: 1755)
Chemistry of inorganic compounds
Zeolite
Structure defined x-ray diffraction pattern
C423S706000, C423S713000
Reexamination Certificate
active
06569401
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to new crystalline molecular sieve SSZ-64 and a method for preparing SSZ-64 using a N-cyclobutylmethyl-N-ethylhexamethyleneiminium cation or N-cyclobutylmethyl-N-ethylheptamethyleneiminium cation structure directing agent.
2. State of the Art
Because of their unique sieving characteristics, as well as their catalytic properties, crystalline molecular sieves and zeolites are especially useful in applications such as hydrocarbon conversion, gas drying and separation. Although many different crystalline molecular sieves have been disclosed, there is a continuing need for new zeolites with desirable properties for gas separation and drying, hydrocarbon and chemical conversions, and other applications. New zeolites may contain novel internal pore architectures, providing enhanced selectivities in these processes.
Crystalline aluminosilicates are usually prepared from aqueous reaction mixtures containing alkali or alkaline earth metal oxides, silica, and alumina. Crystalline borosilicates are usually prepared under similar reaction conditions except that boron is used in place of aluminum. By varying the synthesis conditions and the composition of the reaction mixture, different zeolites can often be formed.
SUMMARY OF THE INVENTION
The present invention is directed to a family of crystalline molecular sieves with unique properties, referred to herein as “molecular sieve SSZ-64” or simply “SSZ-64”. Preferably, SSZ-64 is obtained in its silicate, aluminosilicate, titanosilicate, vanadosilicate or borosilicate form. The term “silicate” refers to a molecular sieve having a high mole ratio of silicon oxide relative to aluminum oxide, preferably a mole ratio greater than 100, including molecular sieves comprised entirely of silicon oxide. As used herein, the term “aluminosilicate” refers to a molecular sieve containing both alumina and silica and the term “borosilicate” refers to a molecular sieve containing oxides of both boron and silicon.
In accordance with this invention, there is provided a molecular sieve having a mole ratio greater than about 15 of an oxide of a first tetravalent element to an oxide of a second tetravalent element different from said first tetravalent element, trivalent element, pentavalent element or mixture thereof and having, after calcination, the X-ray diffraction lines of Table II. It should be noted that that the phrase “mole ratio greater than 15” refers to SSZ-64 containing both the first and second oxides, as well as to SSZ-64 containing only the first oxide, i.e., the mole ratio of the first oxide to the “second” oxide is infinity. To produce SSZ-64 containing only the first oxide, it may be necessary to prepare a version of SSZ-64 containing both the first and second oxides, and then remove the metal atoms of the second oxide.
Further, in accordance with this invention, there is provided a molecular sieve having a mole ratio greater than about 15 of an oxide selected from silicon oxide, germanium oxide and mixtures thereof to an oxide selected from aluminum oxide, gallium oxide, iron oxide, boron oxide, titanium oxide, indium oxide, vanadium oxide and mixtures thereof and having, after calcination, the X-ray diffraction lines of Table II below.
The present invention further provides such a molecular sieve having a composition, as synthesized and in the anhydrous state, in terms of mole ratios as follows:
YO
2
/W
c
O
d
15-180
M
2
/YO
2
0.01-0.03
Q/YO
2
0.02-0.05
wherein Y is silicon, germanium or a mixture thereof; W is aluminum, gallium, iron, boron, titanium, indium, vanadium or mixtures thereof; c is 1 or 2; d is 2 when c is 1 (i.e., W is tetravalent) or d is 3 or 5 when c is 2 (i.e., d is 3 when W is trivalent or 5 when W is pentavalent); M is an alkali metal cation, alkaline earth metal cation or mixtures thereof; n is the valence of M (i.e., 1 or 2); and Q is a N-cyclobutylmethyl-N-ethylhexamethyleneiminium cation or N-cyclobutylmethyl-N-ethylheptamethyleneiminium cation.
In accordance with this invention, there is also provided a molecular sieve prepared by thermally treating a zeolite having a mole ratio of an oxide selected from silicon oxide, germanium oxide and mixtures thereof to an oxide selected from aluminum oxide, gallium oxide, iron oxide, boron oxide, titanium oxide, indium oxide, vanadium oxide and mixtures thereof greater than about 15 at a temperature of from about 200° C. to about 800° C., the thus-prepared zeolite having the X-ray diffraction lines of Table II. The present invention also includes this thus-prepared molecular sieve which is predominantly in the hydrogen form, which hydrogen form is prepared by ion exchanging with an acid or with a solution of an ammonium salt followed by a second calcination.
Also provided in accordance with the present invention is a method of preparing a crystalline material comprising an oxide of a first tetravalent element and an oxide of a second tetravalent element which is different from said first tetravalent element, trivalent element, pentavalent element or mixture thereof, said method comprising contacting under crystallization conditions sources of said oxides and a structure directing agent comprising a N-cyclobutylmethyl-N-ethylhexamethyleneiminium cation or N-cyclobutylmethyl-N-ethylheptamethyleneiminium cation.
DETAILED DESCRIPTION OF THE INVENTION
The present invention comprises a family of crystalline, large pore molecular sieves designated herein “molecular sieve SSZ-64” or simply “SSZ-64”. As used herein, the term “large pore” means having an average pore size diameter greater than about 6.0 Angstroms, preferably from about 6.5 Angstroms to about 7.5 Angstroms.
In preparing SSZ-64, a N-cyclobutylmethyl-N-ethylhexamethyleneiminium cation or N-cyclobutylmethyl-N-ethylheptamethyleneiminium cation is used as a structure directing agent (“SDA”), also known as a crystallization template. In general, SSZ-64 is prepared by contacting an active source of one or more oxides selected from the group consisting of monovalent element oxides, divalent element oxides, trivalent element oxides, and tetravalent element oxides with the N-cyclobutylmethyl-N-ethylhexamethyleneiminium cation or N-cyclobutylmethyl-N-ethylheptamethyleneiminium cation SDA.
SSZ-64 is prepared from a reaction mixture having the composition shown in Table A below.
TABLE A
Reaction Mixture
Typical
Preferred
YO
2
/W
a
O
b
>15
30-70
OH—/YO
2
0.10-0.50
0.20-0.30
Q/YO
2
0.05-0.50
0.10-0.20
M
2
/YO
2
0.02-0.40
0.10-0.25
H
2
O/YO
2
30-80
35-45
where Y, W, Q, M and n are as defined above, and a is 1 or 2, and b is 2 when a is 1 (i.e., W is tetravalent) and b is 3 when a is 2 (i.e., W is trivalent).
In practice, SSZ-64 is prepared by a process comprising:
(a) preparing an aqueous solution containing sources of at least one oxide capable of forming a crystalline molecular sieve and a N-cyclobutylmethyl-N-ethylhexamethyleneiminium cation or N-cyclobutylmethyl-N-ethylheptamethyleneiminium cation having an anionic counterion which is not detrimental to the formation of SSZ-64;
(b) maintaining the aqueous solution under conditions sufficient to form crystals of SSZ-64; and
(c) recovering the crystals of SSZ-64.
Accordingly, SSZ-64 may comprise the crystalline material and the SDA in combination with metallic and non-metallic oxides bonded in tetrahedral coordination through shared oxygen atoms to form a cross-linked three dimensional crystal structure. The metallic and non-metallic oxides comprise one or a combination of oxides of a first tetravalent element(s), and one or a combination of a second tetravalent element(s) different from the first tetravalent element(s), trivalent element(s), pentavalent element(s) or mixture thereof. The first tetravalent element(s) is preferably selected from the group consisting of silicon, germanium and combinations thereof. More preferably, the first tetravalent element is silicon. The second tetravalent element (which is different from the first tetravalent element), trivalent element and pentavalent el
Chevron U.S.A. Inc.
Sample David
Sheridan Richard J.
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