Molecular sieve abstract
Crystalline molecular sieve SSZ-33 is prepared using a mixture
comprising a N,N,N-trialkyl-8-ammonium-tricyclo[5.2.1.0.sup.26]decane
quaternary ammonium cation and a N,N-dialkyl-8-amino-tricyclo[5.2.1.0.sup.26]decane
compound.
Molecular sieve claims
1. A method for preparing a molecular sieve having a mole ratio
of greater than about 15:1 of (1) silicon oxide, germanium oxide
and mixtures thereof to (2) boron oxide or a mixture of boron oxide
with aluminum oxide, gallium oxide, titanium oxide or iron oxide
and mixtures thereof, and having, after calcination, the X-ray diffraction
lines of Table II, said method comprising: A. forming an aqueous
reaction mixture comprising (1) a source of silicon oxide, germanium
oxide and mixtures thereof; (2) a source of boron oxide or a mixture
of boron oxide with aluminum oxide, gallium oxide, titanium oxide
or iron oxide and mixtures thereof; (3) a source of alkali metal
or alkaline earth metal; (4) an N,N,N-trialkyl-8-ammonium-tricyclo[5.2.1.0.sup.26]decane
quaternary ammonium cation, and (5) an N,N-dialkyl-8-amino-tricyclo[5.2.1.0.sup.26]decane
compound; and B. maintaining said aqueous mixture under sufficient
crystallization conditions until crystals are formed.
2. The method of claim 1 wherein the reaction mixture has a composition
in terms of mole ratios falling within the ranges shown below: TABLE-US-00009
YO.sub.2/W.sub.aO.sub.b 10-200 OH.sup.-/YO.sub.2 0.10-1.0 Q/YO.sub.2
0.05-0.50 M.sup.n+/YO.sub.2 0.05-0.30 H.sub.2O/YO.sub.2 15-300 Q/Q
+ M.sup.n+ 0.30-0.70
where Y is silicon, germanium or a mixture thereof, W is boron,
or a mixture of boron, aluminum, gallium, titanium, iron or mixtures
thereof, a is 1 or 2 b is 2 when a is 1 b is 3 when a is 2 M
is an alkali metal or alkaline earth metal, n is the valence of
M, and Q is a mixture of a N,N,N-trialkyl-8-ammonium-tricyclo[5.2.1.0.sup.26]decane
quaternary ammonium cation and a N,N-dialkyl-8-amino-tricyclo[5.2.1.0.sup.26]decane
compound.
3. The method of claim 2 wherein the reaction mixture has a composition
in terms of mole ratios falling within the ranges shown below: TABLE-US-00010
YO.sub.2/W.sub.aO.sub.b 30-60 OH.sup.-/YO.sub.2 0.20-0.30 Q/YO.sub.2
0.10-0.25 M.sup.n+/YO.sub.2 0.05-0.15 H.sub.2O/YO.sub.2 25-60 Q/Q
+ M.sup.n+ 0.40-0.60
4. The method of claim 1 wherein the N,N,N-trialkyl-8-ammonium-tricyclo[5.2.1.0.sup.26]decane
quaternary ammonium cation is used in an amount less than that required
to fill all of the micropore volume of the molecular sieve.
5. The method of claim 1 wherein the mole ratio of N,N,N-trialkyl-8-ammonium-tricyclo[5.2.1.0.sup.26]decane
quaternary ammonium cation to N,N-dialkyl-8-amino-tricyclo[5.2.1.0.sup.26]decane
compound is about 1:4 and higher.
6. The method of claim 5 wherein the mole ratio of N,N,N-trialkyl-8-ammonium-tricyclo[5.2.1.0.sup.26]decane
quaternary ammonium cation to N,N-dialkyl-8-amino-tricyclo[5.2.1.0.sup.26]decane
compound is about 1:4 to about 4:1.
7. The method of claim 1 wherein the amount of boron in the molecular
sieve is greater than 100 parts per million.
8. A molecular sieve having a composition, as-synthesized and in
the anhydrous state, in terms of mole ratios as follows: (1 to 5)
Q:(0.1 to 1) M.sup.n+:W.sub.aO.sub.b:(greater than 15) YO.sub.2
where Y is silicon, germanium or a mixture thereof, W is boron,
or a mixture of boron, aluminum, gallium, titanium, iron or mixtures
thereof, a is 1 or 2 b is 2 when a is 1 b is 3 when a is 2 M
is an alkali metal or alkaline earth metal, n is the valence of
M, and Q is a mixture of a N,N,N-trialkyl-8-ammonium-tricyclo[5.2.1.0.sup.26]decane
quaternary ammonium cation and a N,N-dialkyl-8-amino-tricyclo[5.2.1.0.sup.26]decane
compound.
9. The molecular sieve of claim 8 wherein the N,N,N-trialkyl-8-ammonium-tricyclo[5.2.1.0.sup.26]decane
quaternary ammonium cation is used in an amount less than that required
to fill all of the micropore volume of the molecular sieve.
10. The molecular sieve of claim 8 wherein the mole ratio of N,N,N-trialkyl-8-ammonium-tricyclo[5.2.1.0.sup.26]decane
quaternary ammonium cation to N,N-dialkyl-8-amino-tricyclo[5.2.1.0.sup.26]decane
compound is about 1:4 and higher.
11. The molecular sieve of claim 10 wherein the mole ratio of N,N,N-trialkyl-8-ammonium-tricyclo[5.2.1.0.sup.26]decane
quaternary ammonium cation to N,N-dialkyl-8-amino-tricyclo[5.2.1.0.sup.26]decane
compound is about 1:4 to about 4:1.
12. The molecular sieve of claim 8 wherein the amount of boron
in the molecular sieve is greater than 100 parts per million.
13. The molecular sieve of claim 8 wherein the molecular sieve
has, after calcination, the X-ray diffraction lines of Table II.
14. An improved method for preparing a molecular sieve from source
materials for said molecular sieve and an organic structure directing
agent, the improvement comprising employing a structure directing
agent comprising a mixture of an N,N,N-trialkyl-8-ammonium-tricyclo[5.2.1.0.sup.26]decane
quaternary ammonium cation, and an N,N-dialkyl-8-amino-tricyclo[5.2.1.0.sup.26]decane
compound.
15. The method of claim 14 wherein the N,N,N-trialkyl-8-ammonium-tricyclo[5.2.1.0.sup.26]decane
quaternary ammonium cation is used in an amount less than that required
to fill all of the micropore volume of the molecular sieve
16. The method of claim 14 wherein the mole ratio of N,N,N-trialkyl-8-ammonium-tricyclo[5.2.1.0.sup.26]decane
quaternary ammonium cation to N,N-dialkyl-8-amino-tricyclo[5.2.1.0.sup.26]decane
compound is about 1:4 and higher.
17. The method of claim 16 wherein the mole ratio of N,N,N-trialkyl-8-ammonium-tricyclo[5.2.1.0.sup.26]decane
quaternary ammonium cation to N,N-dialkyl-8-amino-tricyclo[5.2.1.0.sup.26]decane
compound is about 1:4 to about 4:1.
18. The method of claim 14 wherein the amount of boron in the molecular
sieve is greater than 100 parts per million.
19. The method of claim 14 wherein the molecular sieve has, after
calcination, the X-ray diffraction lines of Table II.
Molecular sieve description
BACKGROUND
[0001] Crystalline molecular sieves are usually prepared from aqueous
reaction mixtures containing sources of alkali or alkaline earth
metal oxides, sources of silicon oxide, and, optionally, sources
of, e.g., boron oxide and/or aluminum oxide.
[0002] Molecular sieves have been prepared from reaction mixtures
containing an organic structure directing agent ("SDA"),
usually a nitrogen-containing organic cation. U.S. Pat. No. 4963337
issued Oct. 16 1990 to Zones, discloses that the molecular sieve
designated SSZ-33 can be prepared using a tricyclo[5.2.1.0.sup.26]
decane quaternary ammonium cation SDA.
[0003] U.S. Pat. No. 5785947 issued Jul. 28 1998 to Zones et
al., discloses a method of preparing crystalline zeolites using
a small quantity of an organic templating compound and a larger
quantity of an amine component containing at least one amine having
from one to eight carbon atoms, ammonium hydroxide, or mixtures
thereof. It is disclosed that the amine component is preferably
an aliphatic or cycloaliphatic amine containing no more than eight
carbon atoms. Disclosed examples of the amine component are isopropylamine,
isobutylamine, n-butylamine, piperidine, 4-methylpiperidine, cyclohexylamine,
1133-tetramethyl-butylamine and cyclopentylamine.
[0004] U.S. Pat. No. 5707600 issued Jan. 13 1998 to Nakagawa
et al., discloses a process for preparing medium pore size zeolites
using small, neutral amines capable of forming the zeolite, the
amine containing (a) only carbon, nitrogen and hydrogen atoms, (b)
one primary, secondary or tertiary, but not quaternary, amino group,
and (c) a tertiary nitrogen atom, at least one tertiary carbon atom,
or a nitrogen atom bonded directly to at least one secondary carbon
atom, wherein the process is conducted in the absence of a quaternary
ammonium compound. Disclosed examples of the small, neutral amine
are isobutylamine, diisobutylamine, trimethylamine, cyclopentylamine,
diisopropylamine, sec-butylamine, 25-dimethylpyrrolidine and 26-dimethylpiperidine.
[0005] U.S. Pat. No. 5707601 issued Jan. 13 1998 to Nakagawa,
discloses a process for preparing zeolites having the MTT crystal
structure using small, neutral amines capable of forming the zeolite,
the amine containing (a) only carbon, nitrogen and hydrogen atoms,
(b) one primary, secondary or tertiary, but not quaternary, amino
group, and (c) a tertiary nitrogen atom, at least one tertiary carbon
atom, or a nitrogen atom bonded directly to at least one secondary
carbon atom, wherein the process is conducted in the absence of
a quaternary ammonium compound. Disclosed examples of the small,
neutral amine are isobutylamine, diisobutylamine, diisopropylamine
and trimethylamine.
SUMMARY OF THE INVENTION
[0006] In accordance with this invention there is provided a method
for preparing a molecular sieve having a mole ratio of greater than
about 15:1 of (1) silicon oxide, germanium oxide and mixtures thereof
to (2) boron oxide or a mixture of boron oxide with aluminum oxide,
gallium oxide, titanium oxide or iron oxide and mixtures thereof,
and having, after calcination, the X-ray diffraction lines of Table
II, said method comprising: [0007] A. forming an aqueous reaction
mixture comprising (1) a source of silicon oxide, germanium oxide
and mixtures thereof; (2) a source of boron oxide or a mixture of
boron oxide with aluminum oxide, gallium oxide, titanium oxide or
iron oxide and mixtures thereof; (3) a source of alkali metal or
alkaline earth metal; (4) an N,N,N-trialkyl-8-ammonium-tricyclo[5.2.1.0.sup.26]decane
quaternary ammonium cation, and (5) an N,N-dialkyl-8-amino-tricyclo[5.2.1.0.sup.26]decane
compound; and [0008] B. maintaining said aqueous mixture under sufficient
crystallization conditions until crystals are formed.
[0009] The reaction mixture should have a composition in terms
of mole ratios falling within the ranges shown in Table A below:
TABLE-US-00001 TABLE A Broad Preferred YO.sub.2/W.sub.aO.sub.b 10-200
30-60 OH.sup.-/YO.sub.2 0.10-1.0 0.20-0.30 Q/YO.sub.2 0.05-0.50
0.10-0.25 M.sup.n+/YO.sub.2 0.05-0.30 0.05-0.15 H.sub.2O/YO.sub.2
15-300 25-60 Q/Q + M.sup.n+ 0.30-0.70 0.40-0.60
where Y is silicon, germanium or a mixture thereof, W is boron,
or a mixture of boron, aluminum, gallium, titanium, iron or mixtures
thereof, a is 1 or 2 b is 2 when a is 1 (i.e., W is tetravalent),
b is 3 when a is 2 (i.e., W is trivalent), M is an alkali metal
or alkaline earth metal, n is the valence of M (i.e., 1 or 2), and
Q is a mixture of a N,N,N-trialkyl-8-ammonium-tricyclo[5.2.1.0.sup.26]decane
quaternary ammonium cation and a N,N-dialkyl-8-amino-tricyclo[5.2.1.0.sup.26]decane
compound.
[0010] In one embodiment, the present invention provides these
processes wherein the N,N,N-trialkyl-8-ammonium-tricyclo[5.2.1.0.sup.26]decane
quaternary ammonium cation is used in an amount less than that required
to fill all of the micropore volume of the molecular sieve, i.e.,
an amount less than that required to crystallize the molecular sieve
in the absence of the N,N-dialkyl-8-amino-tricyclo[5.2.1.0.sup.26]decane
compound. Typically, the mole ratio of N,N,N-trialkyl-8-ammonium-tricyclo[5.2.1.0.sup.26]decane
quaternary ammonium cation to N,N-dialkyl-8-amino-tricyclo[5.2.1.0.sup.26]decane
compound is about 1:4 and higher, for example about 1:4 to about
4:1.
[0011] In accordance with this invention, there is also provided
a molecular sieve having a composition, as-synthesized and in the
anhydrous state, in terms of mole ratios as follows: [0012] (1 to
5) Q:(0.1 to 1) M.sup.n+:W.sub.aO.sub.b:(greater than 15) YO.sub.2
where Q, M, n, W, a, b and Y are as defined above.
[0013] The as-synthesized molecular sieve can have a boron content
of greater than 100 parts per million by weight.
[0014] In one embodiment, the present invention provides the as-synthesized
molecular sieve wherein the N,N,N-trialkyl-8-ammonium-tricyclo[5.2.1.0.sup.26]decane
quaternary ammonium cation is used in an amount less than that required
to fill all of the micropore volume of the molecular sieve, i.e.,
an amount less than that required to crystallize the molecular sieve
in the absence of the N,N-dialkyl-8-amino-tricyclo[5.2.1.0.sup.26]decane
compound. Typically, the mole ratio of N,N,N-trialkyl-8-ammonium-tricyclo[5.2.1.0.sup.26]decane
quaternary ammonium cation to N,N-dialkyl-8-amino-tricyclo[5.2.1.0.sup.26]decane
compound is about 1:4 and higher, for example about 1:4 to about
4:1.
[0015] There is further provided in accordance with this invention
an improved method for preparing a molecular sieve from source materials
for said molecular sieve and an organic structure directing agent,
the improvement comprising employing a structure directing agent
comprising a mixture of an N,N,N-trialkyl-8-ammonium-tricyclo[5.2.1.0.sup.26]decane
quaternary ammonium cation, and an N,N-dialkyl-8-amino-tricyclo[5.2.1.0.sup.26]decane
compound.
[0016] In one embodiment, the present invention provides this improved
method wherein the N,N,N-trialkyl-8-ammonium-tricyclo[5.2.1.0.sup.26]decane
quaternary ammonium cation is used in an amount less than that required
to fill all of the micropore volume of the molecular sieve, i.e.,
an amount less than that required to crystallize the molecular sieve
in the absence of the N,N-dialkyl-8-amino-tricyclo[5.2.1.0.sup.26]decane
compound. Typically, the mole ratio of N,N,N-trialkyl-8-ammonium-tricyclo[5.2.1.0.sup.26]decane
quaternary ammonium cation to N,N-dialkyl-8-amino-tricyclo[5.2.1.0.sup.26]decane
compound is about 1:4 and higher, for example about 1:4 to about
4:1.
DETAILED DESCRIPTION
[0017] Molecular sieve SSZ-33 can be prepared by a method comprising
preparing an aqueous mixture that contains a N,N,N-trialkyl-8-ammonium-tricyclo[5.2.1.0.sup.26]decane
quaternary ammonium cation, and a N,N-dialkyl-8-amino-tricyclo[5.2.1.0.sup.26]decane
compound. Typically, the mole ratio of N,N,N-trialkyl-8-ammonium-tricyclo[5.2.1.0.sup.26]decane
quaternary ammonium cation to N,N-dialkyl-8-amino-tricyclo[5.2.1.0.sup.26]decane
compound is about 1:4 and higher, for example about 1:4 to about
4:1. Preferably, seeds of SSZ-33 are used in the preparation.
[0018] This invention provides considerable cost improvement over
the use of a N,N,N-trialkyl-8-ammonium-tricyclo[5.2.1.0.sup.26]decane
quaternary ammonium cation SDA alone.
[0019] SSZ-33 molecular sieves can be suitably prepared from an
aqueous reaction mixture containing sources of an alkali metal or
alkaline earth metal oxide, sources of an oxide of silicon, germanium
or mixtures thereof, sources of boron oxide or boron oxide and aluminum
oxide, gallium oxide, titanium oxide or iron oxide and mixtures
thereof, a N,N,N-trialkyl-8-ammonium-tricyclo[5.2.1.0.sup.26]decane
quaternary ammonium cation and a N,N-dialkyl-8-amino-tricyclo[5.2.1.0.sup.26]decane
compound. The mixture should have a composition in terms of mole
ratios falling within the ranges shown in Table A below: TABLE-US-00002
TABLE A Broad Preferred YO.sub.2/W.sub.aO.sub.b 10-200 30-60 OH.sup.-/YO.sub.2
0.10-1.0 0.20-0.30 Q/YO.sub.2 0.05-0.50 0.10-0.25 M.sup.n+/YO.sub.2
0.05-0.30 0.05-0.15 H.sub.2O/YO.sub.2 15-300 25-60 Q/Q + M.sup.n+
0.30-0.70 0.40-0.60
where Y is silicon, germanium or a mixture thereof; W is boron,
or a mixture of boron, aluminum, gallium, titanium, iron or mixtures
thereof, a is 1 or 2 b is 2 when a is 1 (i.e., W is tetravalent),
b is 3 when a is 2 (i.e., W is trivalent), M is an alkali metal
or alkaline earth metal; n is the valence of M (i.e., 1 or 2); and
Q is a mixture of a N,N,N-trialkyl-8-ammonium-tricyclo[5.2.1.0.sup.26]decane
quaternary ammonium cation and a N,N-dialkyl-8-amino-tricyclo[5.2.1.0.sup.26]decane
compound.
[0020] The reaction mixture is prepared using standard molecular
sieve preparation techniques. Sources of boron for the reaction
mixture include borosilicate glasses and other reactive boron oxides.
These include borates, boric acid and borate esters. Typical sources
of silicon oxide include fumed silica, silicates, silica hydrogel,
silicic acid, colloidal silica, tetra-alkyl orthosilicates, and
silica hydroxides. Sources of other oxides, such as aluminum oxide,
gallium oxide, titanium oxide or iron oxide are analogous to those
for boron oxide and silicon oxide.
[0021] Mixture Q comprises a N,N,N-trialkyl-8-ammonium-tricyclo[5.2.1.0.sup.26]decane
quaternary ammonium cation and a N,N-dialkyl-8-amino-tricyclo[5.2.1.0.sup.26]decane
compound. The N,N,N-trialkyl-8-ammonium-tricyclo[5.2.1.0.sup.26]decane
quaternary ammonium cation has the formula where R.sup.1 R.sup.2
and R.sup.3 are each independently a lower alkyl, for example methyl.
The cation is associated with an anion, A.sup.-, which is not detrimental
to the formation of the SSZ-33. Representative of such anions include
halogens, such as fluoride, chloride, bromide and iodide; hydroxide;
acetate; sulfate and carboxylate. Hydroxide is the preferred anion.
It may be beneficial to ion exchange, for example, a halide for
hydroxide ion, thereby reducing or eliminating the alkali metal
or alkaline earth metal hydroxide required.
[0022] The N,N,N-trialkyl-8-ammonium-tricyclo[5.2.1.0.sup.26]decane
quaternary ammonium cation can be synthesized in the manner described
in Example 1 of aforementioned U.S. Pat. No. 4963337 which is
incorporated herein by reference in its entirety.
[0023] The N,N-dialkyl-8-amino-tricyclo[5.2.1.0.sup.26]decane
compound has the formula where R.sup.1 and R.sup.2 are as defined
above. Synthesis of the N,N-dialkyl-8-amino-tricyclo[5.2.1.0.sup.26]decane
compound is also described in U.S. Pat. No. 4963337 the N,N-dialkyl-8-amino-tricyclo[5.2.1.0.sup.26]decane
compound being an intermediate for the N,N,N-trialkyl-8-ammonium-tricyclo[5.2.1.0.sup.26]decane
quaternary ammonium cation.
[0024] Mixture Q typically has a mole ratio of N,N,N-trialkyl-8-ammoniumtricyclo[5.2.1.0.sup.26]decane
quaternary ammonium cation to N,N-dialkyl-8-amino-tricyclo[5.2.1.0.sup.26]decane
compound of about 1:4 and higher, for example about 1:4 to about
4:1.
[0025] Use of a N,N-dialkyl-8-amino-tricyclo[5.2.1.0.sup.26]decane
compound in mixture Q permits a reduction in the amount of N,N,N-trialkyl-8-ammonium-tricyclo[5.2.1.0.sup.26]decane
quaternary ammonium cation used in mixture Q, which results in significant
cost savings. In fact, it has been found that, by using a N,N-dialkyl-8-amino-tricyclo[5.2.1.0.sup.26]decane
compound in mixture Q, the amount of N,N,N-trialkyl-8-ammonium-tricyclo[5.2.1.0.sup.26]decane
quaternary ammonium cation can be reduced to a level below that
which is required to fill the micropore volume of SSZ-33 i.e.,
an amount less than that required to crystallize SSZ-33 in the absence
of the N,N-dialkyl-8-amino-tricyclo[5.2.1.0.sup.26]decane compound.
[0026] The reaction mixture can be seeded with SSZ-33 crystals
both to direct and accelerate the crystallization, as well as to
minimize the formation of undesired contaminants. Typically, when
seeds are employed they are used in an amount which is about 2-3
weight percent based on the weight of silicon oxide in the reaction
mixture.
[0027] The reaction mixture is maintained at an elevated temperature
until crystals of SSZ-33 are formed. The temperatures during the
hydrothermal crystallization step are typically maintained from
about 140.degree. C. to about 200.degree. C., preferably from about
150.degree. C. to about 170.degree. C., and most preferably from
about 155.degree. C. to about 165.degree. C. The crystallization
period is typically greater than 1 day and preferably from about
3 days to about 7 days.
[0028] The hydrothermal crystallization is conducted under pressure
and usually in an autoclave so that the reaction mixture is subject
to autogenous pressure. The reaction mixture can be stirred, such
as by rotating the reactor, during crystallization. During the hydrothermal
crystallization step, the SSZ-33 crystals can be allowed to nucleate
spontaneously from the reaction mixture.
[0029] Once the SSZ-33 crystals have formed, the solid product
can be separated from the reaction mixture by standard mechanical
separation techniques such as filtration. The crystals can be water-washed
and then dried, e.g., at 90.degree. C. to 150.degree. C. for from
8 to 24 hours, to obtain the as-synthesized SSZ-33 crystals. The
drying step can be performed at atmospheric or subatmospheric pressures.
[0030] As used herein, the term "as-synthesized" means
that the molecular sieve crystals have been recovered from the reaction
mixture and still contain the SDA in their pores, i.e., the SDA
has not been removed from the molecular sieve crystals by (typically)
calcination. SSZ-33 molecular sieve has a composition, as-synthesized
and in the anhydrous state, in terms of mole ratios as indicated
in Table B below: TABLE-US-00003 TABLE B As-Synthesized SSZ-33 Composition
(1 to 5) Q:(0.1 to 1) M.sup.n+:W.sub.aO.sub.b:(greater than 15)
YO.sub.2
where Q, M, n, W, a, b and Y are as defined above.
[0031] As-synthesized SSZ-33 can have a boron content of greater
than 100 parts per million.
[0032] SSZ-33 molecular sieves, as-synthesized, have a crystalline
structure whose X-ray powder diffraction pattern shows the following
characteristic lines: TABLE-US-00004 TABLE I As-Synthesized SSZ-33
2 Theta.sup.a d spacing (Angstroms) Intensity.sup.b 7.86 11.25 VS
20.48 4.336 VS 21.47 4.139 M-S 22.03 4.035 VS 23.18 3.837 S-VS 26.83
3.323 M-S .sup.a.+-.0.1 .sup.bThe X-ray patterns provided are based
on a relative intensity scale in which the strongest line in the
X-ray pattern is assigned a value of 100: W(weak) is less than 20;
M(medium) is between 20 and 40; S(strong) is between 40 and 60;
VS(very strong) is greater than 60.
[0033] Table IA below shows the characteristic X-ray powder diffraction
lines of as-synthesized SSZ-33 including actual relative intensities.
TABLE-US-00005 TABLE IA As-Synthesized SSZ-33 2 Theta.sup.a d spacing
(Angstroms) Rel. Intensity (100 .times. I/I.sub.0) 7.86 11.25 90
20.48 4.336 100 21.47 4.139 40 22.03 4.035 90 23.18 3.837 64 26.83
3.323 40 .sup.a.+-.0.1 SSZ-33 molecular sieves can be used as-synthesized
or can be thermally treated (calcined). By "thermal treatment"
is meant heating to a temperature from about 200.degree. C. to about
820.degree. C., either with or without the presence of steam. Usually,
it is desirable to remove the alkali # metal or alkaline earth metal
cation by ion exchange and replace it with hydrogen, ammonium, or
any desired metal ion. Thermal treatment including steam helps to
stabilize the crystalline lattice from attack by acids.
[0034] After calcination, SSZ-33 molecular sieves have a crystalline
structure whose X-ray powder diffraction pattern shows the characteristic
lines as indicated in Table II below. TABLE-US-00006 TABLE II Calcined
SSZ-33 2 Theta.sup.a d spacing (Angstroms) Intensity 7.81 11.32
VS 20.43 4.347 M-S 21.44 4.144 W 22.02 4.037 M 23.18 3.837 M 26.80
3.326 M .sup.a.+-.0.1
[0035] Table IIA below shows the characteristic X-ray powder diffraction
lines of calcined SSZ-33 including actual relative intensities.
TABLE-US-00007 TABLE IIA Calcined SSZ-33 2 Theta.sup.a d spacing
(Angstroms) Rel. Intensity (100 .times. I/I.sub.0) 7.81 11.32 100
20.43 4.347 46 21.44 4.144 9 22.02 4.037 41 23.18 3.837 28 26.80
3.326 31 .sup.a.+-.0.1
[0036] The X-ray powder diffraction patterns were determined by
standard techniques. The radiation was the K-alpha/doublet of copper
and a scintillation counter spectrometer with a strip-chart pen
recorder was used. The peak heights I and the positions, as a function
of 2 Theta where Theta is the Bragg angle, were read from the spectrometer
chart. From these measured values, the relative intensities, 100.times.I/I.sub.o,
where I.sub.o is the intensity of the strongest line or peak, and
d, the interplanar spacing in Angstroms corresponding to the recorded
lines, can be calculated.
[0037] Variations in the diffraction pattern can result from variations
in the silica-to-boron mole ratio from sample to sample. The molecular
sieve produced by exchanging the metal or other cations present
in the molecular sieve with various other cations yields a similar
diffraction pattern, although there can be shifts in interplanar
spacing as well as variations in relative intensity. Calcination
can also cause shifts in the X-ray diffraction pattern. Notwithstanding
these perturbations, the basic crystal lattice structure remains
unchanged.
[0038] SSZ-33 molecular sieves are useful in hydrocarbon conversion
reactions. Examples of these uses are described in U.S. Pat. No.
4963337 issued Oct. 16 1990 to Zones, which is incorporated
herein by reference. |