Molecular sieve abstract
A large pore (metallo)aluminophosphate molecular sieve is disclosed
The material has an X-ray diffraction pattern including the lines
listed in Table 4 and is synthesized in the presence of 4-dimethylaminopyridine
as structure directing agent.
Molecular sieve claims
1. A crystalline molecular sieve having a framework comprising
tetrahedrally coordinated atoms (T) connected by bridging atoms
and having the coordination sequence and vertex symbols listed in
Table 3.
2. A crystalline molecular sieve having, in its as-synthesized
form, an X-ray diffraction pattern including the lines listed in
Table 4.
3. A crystalline molecular sieve having, in its calcined form,
an X-ray diffraction pattern including the lines listed in Table
5.
4. A crystalline material comprising [AlO.sub.4] and [PO.sub.4]
corner sharing tetrahedral units and having an X-ray diffraction
pattern including the lines listed in Table 4.
5. The crystalline material of claim 4 and also comprising [SiO.sub.4]
corner sharing tetrahedral units.
6. The crystalline material of claim 4 and represented by the empirical
formula, on an anhydrous basis: mR:F.sub.a:(M.sub.xAl.sub.yP.sub.z)O.sub.2
wherein R represents at least one directing agent; wherein m is
the number of moles of R per mole of (M.sub.xAl.sub.yP.sub.z)O.sub.2;
wherein a is the number of moles of fluoride ion (F) per mole of
(M.sub.xAl.sub.yP.sub.z)O.sub.2; wherein x, y, and z represent the
mole fraction of M, Al and P as tetrahedral oxides; and wherein
M is a metal selected from one of Groups 1 to 14 and Lanthanoids
of the Periodic Table of Elements.
7. The crystalline material of claim 6 wherein m has a value from
0 to about
8. The crystalline material of claim 6 wherein m has a value from
about 0.1 to about 0.5.
9. The crystalline material of claim 6 wherein R is 4-dimethylaminopyridine.
10. The crystalline material of claim 6 wherein a/y is less than
0.25.
11. The crystalline material of claim 6 wherein a/y is 0.
12. The crystalline material of claim 6 wherein M is selected from
one of the group consisting of B, Co, Cr, Cu, Fe, Ga, Ge, Mg, Mn,
Ni, Sn, Ti, Zn and Zr.
13. The crystalline material of claim 6 wherein M is silicon.
14. The crystalline material of claim 6 wherein x is from 0 to
about 0.25 y is from about 0.3 to about 0.7 and z is from about
0.25 to about 0.7.
15. The crystalline material of claim 6 wherein x is from about
0 to about 0.15 y is from about 0.4 to about 0.6 and z is from
about 0.3 to about 0.6.
16. A porous, crystalline material comprising [AlO.sub.4] and [PO.sub.4]
comer sharing tetrahedral units and having an X-ray diffraction
pattern including the lines listed in Table 5.
17. A method of synthesizing the crystalline material of claim
4 the process comprising: (a) forming a reaction mixture comprising
water; a source of aluminum, a source of phosphorus, optionally
a source of metal other than aluminum, optionally a source of fluoride
ions, and at least one directing agent comprising 4-dimethylaminopyridine
(R); (b) inducing crystallization of said crystalline material from
the reaction mixture; and (c) recovering said crystalline material
from the reaction mixture.
18. The method of claim 17 wherein the reaction mixture has a composition,
in terms of mole ratios, within the following ranges: P.sub.2O.sub.5:
Al.sub.2O.sub.3=0.7 to 1.3 SiO.sub.2: Al.sub.2O.sub.3=0 to 0.9 H.sub.2O:
Al.sub.2O.sub.3=10 to 100 R: Al.sub.2O.sub.3=0.5 to 5.0 F: Al.sub.2O.sub.3=0
to <0.75.
19. The method of claim 18 wherein F: Al.sub.2O.sub.3 is zero.
20. The method of claim 17 wherein the reaction mixture has a composition,
in terms of mole ratios, within the following ranges: P.sub.2O.sub.5:
Al.sub.2O.sub.3=0.9 to 1.1 SiO.sub.2: Al.sub.2O.sub.3=0.05 to 0.5
H.sub.2O: Al.sub.2O.sub.3=20 to 50 R: Al.sub.2O.sub.3=1.0 to 4.0
F: Al.sub.2O.sub.3=0 to 0.5.
21. The method of claim 20 wherein F: Al.sub.2O.sub.3 is zero.
22. The method of claim 17 wherein crystallization of said crystalline
material is conducted at a temperature of about 100.degree. C. to
about 250.degree. C.
23. The method of claim 17 wherein crystallization of said crystalline
material is conducted at a temperature of about 130.degree. C. to
about 200.degree. C.
24. A hydrocarbon conversion process comprising contacting a hydrocarbon
feedstock with a catalyst comprising the porous crystalline material
of claim 4.
25. A hydrocarbon conversion process comprising contacting a hydrocarbon
feedstock with a catalyst comprising a crystalline material produced
by the method of claim 17.
26. A method of synthesizing a crystalline material having the
CHA framework type, the process comprising: (a) forming a reaction
mixture comprising a source of aluminum, a source of metal other
than aluminum, a source of phosphorus, at least one directing agent
comprising 4-dimethylaminopyridine and seeds of a CHA framework
type material, such as SAPO-34; (b) inducing crystallization of
said crystalline material from the reaction mixture; and (c) recovering
said crystalline material from the reaction mixture.
27. A process for converting an oxygenate-containing feedstock
to olefins comprising contacting the feedstock with a catalyst comprising
a porous crystalline material produced by the method of claim 26.
Molecular sieve description
CROSS REFERENCE TO RELATED APPLICATION
[0001] This application claims priority to U.S. Provisional Patent
Application No. 60/615111 filed Oct. 01 2004.
FIELD
[0002] This invention relates to a large pore aluminophosphate
molecular sieve, or a substituted derivative thereof, to a method
of its synthesis in a low fluoride or fluoride-free medium and to
its use in organic conversion reactions.
BACKGROUND
[0003] Crystalline molecular sieves have a 3-dimensional, four-connected
framework structure of corner-sharing [TO.sub.4] tetrahedra, where
T is any tetrahedrally coordinated cation. Among the known forms
of molecular sieve are aluminosilicates, which contain a three-dimensional
microporous crystal framework structure of [SiO.sub.4] and [AlO.sub.4]
corner sharing tetrahedral units, aluminophosphates (ALPOs), in
which the framework structure is composed of [AlO.sub.4] and [PO.sub.4]
corner sharing tetrahedral units and silicoaluminophosphates (SAPOs),
in which the framework structure is composed of [SiO.sub.4], [AlO.sub.4]
and [PO.sub.4] corner sharing tetrahedral units.
[0004] Molecular sieves have been classified by the Structure Commission
of the International Zeolite Association according to the rules
of the IUPAC Commission on Zeolite Nomenclature. According to this
classification, framework-type zeolite and zeolite-type molecular
sieves, for which a structure has been established, are assigned
a three letter code and are described in the Atlas of Zeolite Framework
Types, 5th edition, Elsevier, London, England (2001), which is herein
fully incorporated by reference.
[0005] Molecular sieves are typically described in terms of the
size of the ring that defines a pore, where the size is based on
the number of T atoms in the ring. Other framework-type characteristics
include the arrangement of rings that form a cage, and when present,
the dimension of channels, and the spaces between the cages. See
van Bekkum, et al., Introduction to Zeolite Science and Practice,
Second Completely Revised and Expanded Edition, Volume 137 pages
1-67 Elsevier Science, B. V., Amsterdam, Netherlands (2001).
[0006] In general, molecular sieves can be divided into small,
medium and large pore materials. Thus small pore molecular sieves
typically have pores defined by a ring of no more than 8 T atoms
and have an average pore size less than about 0.5 nm (5 .ANG.).
Medium pore molecular sieves typically have pores defined by a ring
of 10 T atoms and have an average pore size about 0.5 to 0.6 nm
(5 to 6 .ANG.), whereas large pore materials have pores defined
by rings of 12 or more T atoms and a pore size greater than 0.6
nm (6 .ANG.).
[0007] Crystalline molecular sieves, as exemplified by zeolites
and (metallo)aluminophosphates, are commercially important materials
for petroleum processing and petrochemical applications. Because
each unique structure type offers new potential for applications
in catalysis and separations, there has been sustained research
effort, both in industry and academia, for their discovery.
[0008] Many molecular sieves are synthesized in the presence of
an organic directing agent, such as an organic nitrogen compound.
For example, it is known from, for example, U.S. Pat. No. 6680278
that a crystalline silicoaluminophosphate molecular sieve of the
CHA framework type (a small pore material), can be synthesized in
the presence of an organic directing agent mixture comprising tetraethylammonium
cations and one or more dimethylamino moieties selected from one
or more of N,N-dimethylethanolamine, N,N-dimethylpropanolamine,
N,N-dimethylbutanolamine, N,N-dimethylheptanolamine, N,N-dimethylhexanolamine,
N,N-dimethylethylenediamine, N,N-dimethylbutylenediamine, N,N-dimethylheptylenediamine,
N,N-dimethylhexylenediamine 1-dimethylamino-2-propanol, N,N-dimethylethylamine,
N,N-dimethylpropylamine, N,N-dimethylpentylamine, N,N-dimethylhexylamine
and N,N-dimethylheptylamine. Other organic directing agents that
have been used in the synthesis of CHA framework type materials
include isopropylamine or di-n-propylamine triethylamine, cyclohexylamine,
1-methylamidazole, morpholine, pyridine, piperidine, diethylethanolamine,
and N,N,N',N'-tetraethylethylene diamine.
[0009] It is also known to use fluoride-containing compounds, such
as hydrogen fluoride, as mineralizing agents in molecular sieve
synthesis. For example, EP-A-337479 discloses the use of hydrogen
fluoride in water at low pH to mineralize silica in glass for the
synthesis of ZSM-5. In addition, U.S. Patent Application Publication
No. 2003/0231999 published Dec. 18 2003 and incorporated herein
by reference, discloses that aluminophosphate or silicoaluminophosphate
molecular sieves having the CHA framework type can be synthesized
in the presence of fluoride ions using the dimethylamino compounds
disclosed in U.S. Pat. No. 6680278 as directing agents. However,
fluoride-based syntheses pose environmental problems in that they
use hydrogen fluoride in the synthesis medium and/or produce hydrogen
fluoride on calcination to remove the organic directing agent from
the molecular sieve product.
[0010] Currently, an entirely rational approach that leads to the
synthesis of unique framework materials is not available, due to
the fact that all crystalline microporous materials are metastable
phases and they are kinetic products. Their discovery is therefore
often serendipitous.
[0011] Our research has led to two findings: that 4-DMAPy can direct
the synthesis of low-silica SAPO-CHA in a low fluoride or fluoride-free
medium and in the presence of colloidal SAPO-34 seeds; and, from
parallel experiments, that without SAPO-34 seeds, use of the same
directing agent under no- or low-fluoride conditions unexpectedly
led to the production of the present large pore aluminophosphate
designated EMM-8.
[0012] According to an article in the Chemical Journal of Chinese
Universities, Vol. 22 No. 10 pages 192-195 dated October 2001
DMAPy has been used as a template in the synthesis of NK-101 an
aluminophosphate. However, FIG. 1 provides a comparison of the X-ray
diffraction pattern of NK-101 with that of EMM-8 and it is apparent
from this comparison that the material of the invention is different
from NK-101. In particular, in the X-ray diffraction pattern of
NK-101 the most prominent diffraction peaks are at 2-theta values
of approximately 17.degree. and 19.degree., whereas these peaks
are not present in the X-ray diffraction pattern of EMM-8.
[0013] In an article entitled "SSZ-51--A New Aluminophosphate
Zeotype: Synthesis, Crystal Structure, NMR, and Dehydration Properties",
published on the Web by the American Chemical Society on Jun. 23
2004 Morris et al. report that they have synthesized and solved
the structure of a new aluminophosphate zeotype framework structure,
SSZ-5 1 having the empirical formula Al.sub.4(PO.sub.4).sub.4F.C.sub.7N.sub.2H.sub.11.0.5H.sub.2O.
The synthesis employs 4-dimethylaminopyridine as a structure directing
agent and requires the presence of fluoride ion as a mineralizing
agent. The structure of SSZ-51 is said to be closely related to
that of SAPO-40 an AFR framework type material, and to contain
intersecting channels defined by 8- and 12-membered ring windows.
It appears that SSZ-51 is isostructural with EMM-8.
[0014] U.S. Patent Application Publication No. 2003/0232718 published
Dec. 18 2003 discloses the synthesis of silicoaluminophosphate
molecular sieves using templates that contain at least one dimethylamino
moeity. The use of such templates is said to result in good quality
SAPO molecular sieves of CHA framework type.
[0015] EP-A-0 324 082 discloses the synthesis of non-zeolite molecular
sieves by contacting alumina or silica-alumina bodies with a liquid
reaction mixture containing a reactive source of phosphorus and
an organic templating agent.
SUMMARY
[0016] In one aspect, the invention resides in a crystalline molecular
sieve having a framework comprising tetrahedrally coordinated atoms
(T) connected by bridging atoms and having the coordination sequence
and vertex symbols listed in Table 3 below.
[0017] In another aspect, the invention resides in a crystalline
molecular sieve having, in its as-synthesized form, an X-ray diffraction
pattern including the lines listed in Table 4 below. In its calcined
form, the crystalline molecular sieve of the invention has an X-ray
diffraction pattern including the lines listed in Table 5 below.
The phrase "including the lines" as used herein means
that peaks are expected to be present at or close to the lines indicated
in the Tables, but not necessarily in the relative intensities specified,
which can vary depending on a number of factors as discussed later.
[0018] In yet another aspect, the invention resides in a crystalline
material having, in its as-synthesized form, an X-ray diffraction
pattern including the lines listed in Table 4 below and represented,
in its as-synthesized form and on an anhydrous basis, by the empirical
formula: mR:F.sub.a:(M.sub.xAl.sub.yP.sub.z)O.sub.2 wherein R represents
at least one directing agent, preferably 4-dimethylaminopyridine;
m is the number of moles of R per mole of (M.sub.xAl.sub.yP.sub.z)O.sub.2
and m has a value from 0 to 1 such as from 0.1 to about 0.5 for
example from 0.1 to about 0.3; wherein a is the number of moles
of fluoride ion (F) per mole of (M.sub.xAl.sub.yP.sub.z)O.sub.2
and a/y is less than 0.25 and preferably is 0; wherein x, y, and
z represent the mole fraction of M, Al and P, as tetrahedral oxides;
and wherein M is a metal selected from one of Groups 1 to 14 and
Lanthanoids of the Periodic Table of Elements, and preferably M
is selected from B, Co, Cr, Cu, Fe, Ga, Ge, Mg, Mn, Ni, Si, Sn,
Ti, Zn and Zr. Most preferably, M is silicon. In one embodiment,
x is from 0 to about 0.25 y is from about 0.3 to about 0.7 and
z is from about 0.25 to about 0.7. In another embodiment, x is from
0 to about 0.15 y is from about 0.4 to about 0.6 and z is from
about 0.3 to about 0.6. In yet another embodiment, x is from about
0 to about 0.12 y is from about 0.45 to about 0.55 and z is from
about 0.35 to about 0.55. For ALPO molecular sieves, x is zero.
[0019] In still another aspect, the invention resides in a method
of synthesizing the crystalline material of the invention, the process
comprising: (a) forming a reaction mixture comprising water, a source
of aluminum, a source of phosphorus, at least one structure directing
agent comprising 4-dimethylaminopyridine, optionally a source of
metal M and optionally a source of fluoride ion, wherein F: Al.sub.2O.sub.3
molar ratio of said reaction mixture is preferably less than 0.5
and most preferably is 0; (b) inducing crystallization of said crystalline
material from the reaction mixture; and (c) recovering said crystalline
material from the reaction mixture.
[0020] In a further aspect, the invention resides in a method of
synthesizing a crystalline material having the CHA framework type,
the process comprising: (a) forming a reaction mixture comprising
a source of aluminum, a source of phosphorus, optionally a source
of metal M, at least one directing agent comprising 4-dimethylaminopyridine
and seeds of a CHA framework type material, such as SAPO-34; (b)
inducing crystallization of said crystalline material from the reaction
mixture; and (c) recovering said crystalline material from the reaction
mixture.
[0021] In still a further aspect, the invention resides in the
use of the crystalline material of said one aspect of the invention
as a sorbent and as a catalyst in organic conversion reactions.
DESCRIPTION OF THE DRAWINGS
[0022] FIG. 1 is a comparison of the X-ray diffraction pattern
of NK-101 with the X-ray diffraction pattern of Sample A in Example
1 after calcination as in Example 4. The ordinates for the two patterns
are to the same scale and reflect intensity counts.
[0023] FIG. 2 gives the X-ray diffraction patterns of the as-synthesized
products of Example 1 after crystallization for 2 days and 4 days.
[0024] FIG. 3 compares the X-ray diffraction pattern of Sample
A of Example 1 with that of Sample B of Example 2.
[0025] FIG. 4 gives scanning electron micrographs of Sample A of
Example 1 and Sample B of Example 2.
[0026] FIG. 5 is a comparison of the X-ray diffraction patterns
of Sample A of Example 1 and Samples C and D of Example 3.
[0027] FIG. 6 is a comparison of the X-ray diffraction pattern
of Sample A, as-synthesized, with the X-ray diffraction patterns
of Samples A, C and D after calcination as in Example 4.
[0028] FIG. 7 gives the X-ray diffraction patterns of Sample C
as-synthesized and after undergoing a series of calcination, hydration
and dehydration treatments as described in Example 5.
[0029] FIG. 8 gives the X-ray diffraction patterns of the as-synthesized
products of Example 8 after crystallization for 2 days and 4 days.
[0030] FIG. 9 is an illustration of the framework structure of
EMM-8 showing only the tetrahedral atoms.
DETAILED DESCRIPTION OF THE EMBODIMENTS
[0031] In one embodiment, the present invention relates to a porous
crystalline material, EMM-8 and its synthesis in a low fluoride
or fluoride-free medium with the organic directing agent, 4-dimethylaminopyridine.
The crystalline structure remains intact after calcination to remove
the directing agent and adsorption data indicate that the resultant
material has large pores. In particular, the calcined material adsorbs
a significant amount of mesitylene, as well as 22-dimethylbutane,
n-hexane, and methanol. The invention also resides in the use of
EMM-8 as a sorbent and as a catalyst in organic conversion reactions
and to synthesis of CHA framework materials with the organic directing
agent, 4-dimethylaminopyridine.
[0032] The EMM-8 of the invention is a porous crystalline material
having a framework of tetrahedral atoms connected by bridging atoms,
the tetrahedral atom framework being defined by the interconnections
between the tetrahedrally coordinated atoms in its framework. As
with any porous crystalline material, the structure of EMM-8 can
be defined by the interconnections between the tetrahedrally coordinated
atoms in its framework. In particular, EMM-8 has a framework of
tetrahedral (T) atoms connected by bridging atoms, wherein the tetrahedral
atom framework is defined by connecting the nearest tetrahedral
(T) atoms in the manner shown in Table 1 below. TABLE-US-00001 TABLE
1 T atom Connected to: T1 T2 T3 T4 T28 T2 T1 T3 T4 T14 T3
T1 T2 T7 T15 T4 T1 T2 T16 T25 T5 T6 T7 T8 T32 T6 T5 T7
T8 T10 T7 T3 T5 T6 T11 T8 T5 T6 T12 T29 T9 T10 T11 T12
T20 T10 T6 T9 T11 T12 T11 T7 T9 T10 T15 T12 T8 T9 T10 T17
T13 T14 T15 T16 T24 T14 T2 T13 T15 T16 T15 T3 T11 T13 T14
T16 T4 T13 T14 T21 T17 T12 T18 T19 T20 T18 T17 T19 T20
T30 T19 T17 T18 T23 T31 T20 T9 T17 T18 T32 T21 T16 T22 T23
T24 T22 T21 T23 T24 T26 T23 T19 T21 T22 T27 T24 T13 T21
T22 T28 T25 T4 T26 T27 T28 T26 T22 T25 T27 T28 T27 T23 T25
T26 T31 T28 T1 T24 T25 T26 T29 T8 T30 T31 T32 T30 T18 T29
T31 T32 T31 T19 T27 T29 T30 T32 T5 T20 T29 T30
[0033] In addition to describing the structure of EMM-8 by the
interconnections of the tetrahedral atoms as in Table 1 above, it
may be defined by its unit cell, which is the smallest repeating
unit containing all the structural elements of the material. The
pore structure of EMM-8 is illustrated in FIG. 9 (which shows only
the tetrahedral atoms) down the direction of the 12-member ring
channel. There are four unit cell units in FIG. 9 whose limits
are defined by four boxes. Table 2 lists the typical positions of
each tetrahedral atom in the unit cell in units of Angstroms. Each
tetrahedral atom is bonded to bridging atoms, which are also bonded
to adjacent tetrahedral atoms. Tetrahedral atoms are those capable
of having tetrahedral coordination, including one or more of, but
not limiting, lithium, beryllium, boron, magnesium, aluminum, silicon,
phosphorus, titanium, chromium, manganese, iron, cobalt, nickel,
copper, zinc, zirconium, gallium, germanium, arsenic, indium, tin,
and antimony. Bridging atoms are those capable of connecting two
tetrahedral atoms, examples of which include, but are not limited
to oxygen, nitrogen, fluorine, sulfur, selenium, and carbon atoms.
[0034] In the case of oxygen, it is also possible that the bridging
oxygen is also connected to a hydrogen atom to form a hydroxyl group
(--OH--). In the case of carbon it is also possible that the carbon
is also connected to two hydrogen atoms to form a methylene group
(--CH.sub.2--). For example, bridging methylene groups have been
seen in the zirconium diphosphonate, MIL-57. See: C. Serre, G. Ferey,
J. Mater. Chem. 12 p. 2367 (2002). Bridging sulfur and selenium
atoms have been seen in the UCR-20-23 family of microporous materials.
See: N. Zheng, X. Bu, B. Wang, P. Feng, Science 298 p. 2366 (2002).
Bridging fluorine atoms have been seen in lithium hydrazinium fluoroberyllate,
which has the ABW structure type. See: M. R. Anderson, I. D. Brown,
S. Vilminot, Acta Cryst. B29 p. 2626 (1973). Since tetrahedral
atoms may move about due to other crystal forces (presence of inorganic
or organic species, for example), or by the choice of tetrahedral
and bridging atoms, a range of .+-.0.1 nm (.+-.1 Angstrom) is implied
for the x and y coordinate positions and a range of .+-.0.05 nm
(.+-.0.5 Angstrom) for the z coordinate positions in Table 2. TABLE-US-00002
TABLE 2 Positions of tetrahedral (T) atoms for the EMM-8 structure
when T = silicon and the bridging atoms are oxygen. Atom x(nm) y(nm)
z(nm) T1 0.2926 0.2757 0.5573 T2 0.3234 0.1530 0.2716 T3 0.1524
0.1588 0.0121 T4 0.5757 0.1522 0.0821 T5 1.8568 0.2757 0.1383 T6
1.8260 0.1530 0.4240 T7 1.9970 0.1588 0.6835 T8 1.5738 0.1522 0.6135
T9 1.8568 1.0975 0.1383 T10 1.8260 1.2202 0.4240 T11 1.9970 1.2144
0.6835 T12 1.5738 1.2210 0.6135 T13 0.2926 1.0975 0.5573 T14 0.3234
1.2202 0.2716 T15 0.1524 1.2144 0.0121 T16 0.5757 1.2210 0.0821
T17 1.4200 0.9623 0.5573 T18 1.4508 0.8396 0.2716 T19 1.2798 0.8454
0.0121 T20 1.7031 0.8388 0.0821 T21 0.7294 0.9623 0.1383 T22 0.6986
0.8396 0.4240 T23 0.8696 0.8454 0.6835 T24 0.4464 0.8388 0.6135
T25 0.7294 0.4109 0.1383 T26 0.6986 0.5336 0.4240 T27 0.8696 0.5278
0.6835 T28 0.4464 0.5344 0.6135 T29 1.4200 0.4109 0.5573 T30 1.4508
0.5336 0.2716 T31 1.2798 0.5278 0.0121 T32 1.7031 0.5344 0.0821
[0035] The complete structure of EMM-8 is built by connecting multiple
unit cells as defined above in a fully-connected three-dimensional
framework. The tetrahedral atoms in one unit cell are connected
to certain tetrahedral atoms in all of its adjacent unit cells.
While Table 1 lists the connections of all the tetrahedral atoms
for a given unit cell of EMM-8 the connections may not be to the
particular atom in the same unit cell but to an adjacent unit cell.
All of the connections listed in Table 1 are such that they are
to the closest tetrahedral (T) atoms, regardless of whether they
are in the same unit cell or in adjacent unit cells.
[0036] Although the Cartesian coordinates given in Table 2 above
may accurately reflect the positions of tetrahedral atoms in an
idealized structure, the true structure can be more accurately described
by the connectivity between the framework atoms as shown in Table
1 above. Another way to describe this connectivity is by the use
of coordination sequences as applied to microporous frameworks by
W. M. Meier and H. J. Moeck, in the Journal of Solid State Chemistry
27 p. 349 (1979). In a microporous framework, each tetrahedral
atom, N.sub.0 (T-atom) is connected to N.sub.1=4 neighboring T-atoms
through bridging atoms (typically oxygen). These neighboring T-atoms
are then connected to N.sub.2 T-atoms in the next shell. The N.sub.2
atoms in the second shell are connected to N.sub.3 T-atoms in the
third shell, and so on. Each T-atom is only counted once, such that,
for example, if a T-atom is in a 4-membered ring, at the fourth
shell the N.sub.0 atom is not counted a second time, and so on.
Using this methodology, a coordination sequence can be determined
for each unique T-atom of a 4-connected net of T-atoms. The following
line lists the maximum number of T-atoms for each shell. N.sub.0=1
N.sub.1.ltoreq.4 N.sub.2.ltoreq.12 N.sub.3.ltoreq.36 N.sub.k.ltoreq.43.sup.k-1
[0037] For a given T-atom in a 3-dimensional framework, there are
six angles associated with the connections to its 4 neighboring
T-atoms. A way of indicating the size of the smallest ring associated
with each of these six angles, called the vertex symbol, was developed
by M. O'Keeffe and S. T. Hyde in Zeolites 19 p. 370 (1997). The
order is such that opposite pairs of angles are grouped together.
The vertex symbol 4.4.6.6.62.8 for example, indicates that the
first pair of opposite angles contains 4-rings, the second pair
contains 6-rings, and the third pair contains two 6-rings and an
8-ring. The Structure Commission of the International Zeolite Association
recognize that the combination of coordination sequence and vertex
symbol together appear unique for a particular framework topology
such that they can be used to unambiguously distinguish microporous
frameworks of different types (see "Atlas of Zeolite Framework
Types", Ch. Baerlocher, W. M. Meier, D. H. Olson, Elsevier,
Amsterdam (2001). One way to determine the coordination sequence
and vertex symbol for a given structure is from the atomic coordinates
of the framework atoms using the computer program zeoTsites (see
G. Sastre, J. D. Gale, Microporous and mesoporous Materials 43
p. 27 (2001).
[0038] The coordination sequence and vertex symbols for the EMM-8
structure are given in Table 3. The T-atom connectivity as listed
in Table 3 is for T-atoms only. Bridging atoms, such as oxygen usually
connect the T-atoms. Although most of the T-atoms are connected
to other T-atoms through bridging atoms, it is recognized that in
a particular crystal of a material having a framework structure,
it is possible that a number of T-atoms may not be connected to
one another. Reasons for non-connectivity include, but are not limited
by, T-atoms located at the edges of the crystals and by defect sites
caused by, for example, vacancies in the crystal. The framework
listed in Table 3 is not limited in any way by its composition,
unit cell dimensions or space group symmetry. TABLE-US-00003 TABLE
3 Atom Number Atom Symbol Label Coordination Sequence Vertex 1 T1
4 10 17 28 46 63 86 117 142 168 4 6 4 6 6 12 2 T2 4 9 16 27 44 65
87 110 138 171 4 6 4 6.sub.2 4 8 3 T3 4 9 18 30 43 64 90 111 139
178 4 4 4 8 6.sub.3 8 4 T4 4 9 18 29 42 65 91 111 138 176 4 4 4
12 6 6.sub.3
[0039] While the idealized structure contains only 4-coordinate
T-atoms, it is possible under certain conditions that some of the
framework atoms may be 5- or 6-coordinate. This may occur, for example,
under conditions of hydration when the composition of the material
contains mainly phosphorus and aluminum T-atoms. When this occurs
it is found that T-atoms may be also coordinated to one or two oxygen
atoms of water molecules (--OH.sub.2), or of hydroxyl groups (--OH).
For example, the molecular sieve AlPO.sub.4-34 is known to reversibly
change the coordination of some aluminum T-atoms from 4-coordinate
to 5- and 6-coordinate upon hydration as described by A. Tuel et
al. in J. Phys. Chem. B 104 p. 5697 (2000). It is also possible
that some framework T-atoms can be coordinated to fluoride atoms
(--F) when materials are prepared in the presence of fluorine to
make materials with 5-coordinate T-atoms as described by H. Koller
in J. Am. Chem. Soc. 121 p. 3368 (1999).
[0040] It may happen in some particular compositions that, because
of a specific ordering of T-atoms, the actual unit cell may double
in size to allow the specific ordering to occur. This is the case
in the aluminophosphate and metalloalumino-phosphate compositions
of EMM-8 where there are alternating aluminum and phosphorus T-atoms.
For example, the unit cell of the AlPO form of EMM-8 is actually
twice the length along the z-axis as indicated in Table 2 such
that there are 64 T-atoms in the unit cell.
[0041] In its as-synthesized form, EMM-8 typically has an X-ray
diffraction pattern including the lines listed in Table 4 below:
TABLE-US-00004 TABLE 4 2-Theta d, nm Relative Intensity 7.58 .+-.
0.05 1.164 .+-. 0.008 M 8.26 .+-. 0.05 1.069 .+-. 0.007 M 12.66
.+-. 0.05 0.698 .+-. 0.003 S 13.94 .+-. 0.05 0.634 .+-. 0.002 S
14.18 .+-. 0.05 0.623 .+-. 0.002 VS 18.94 .+-. 0.05 0.468 .+-. 0.001
S 19.18 .+-. 0.05 0.462 .+-. 0.001 M 19.60 .+-. 0.05 0.452 .+-.
0.001 S 25.48 .+-. 0.05 0.349 .+-. 0.001 M 25.62 .+-. 0.05 0.347
.+-. 0.001 VS 25.94 .+-. 0.05 0.343 .+-. 0.001 VS 26.12 .+-. 0.05
0.341 .+-. 0.001 M 28.08 .+-. 0.05 0.317 .+-. 0.001 M
[0042] In its as-calcined anhydrous form, EMM-8 is porous and has
an X-ray diffraction pattern including the lines listed in Table
5 below: TABLE-US-00005 TABLE 5 2-Theta d, nm Relative Intensity
7.54 .+-. 0.05 1.171 .+-. 0.008 VS 7.94 .+-. 0.05 1.112 .+-. 0.007
M 12.68 .+-. 0.05 0.697 .+-. 0.003 W 13.54 .+-. 0.05 0.653 .+-.
0.003 W 14.24 .+-. 0.05 0.621 .+-. 0.002 M 18.82 .+-. 0.05 0.471
.+-. 0.001 W 19.80 .+-. 0.05 0.448 .+-. 0.001 W 20.10 .+-. 0.05
0.441 .+-. 0.001 W 25.46 .+-. 0.05 0.349 .+-. 0.001 W 25.90 .+-.
0.05 0.344 .+-. 0.001 W 26.46 .+-. 0.05 0.336 .+-. 0.001 W
[0043] These, and all other X-ray diffraction data referred to
herein, were collected with a Siemens D500 diffractometer with a
voltage of 40 kV and a current of 30 mA using a copper target (.lamda.=0.154
nm) and a curved graphite monochrometer. 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 1 second for each step.
The interplanar spacings, d's, were calculated in nanometres (nm),
and the relative intensities of the lines, I/Io, where 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 (75-100), s=strong (50-74), m=medium (25-49) and
w=weak (0-24). 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 crystallite
sizes or very high experimental resolution or crystallographic change,
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 topology of 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, and thermal and/or
hydrothermal history. In practice, therefore, at least some of the
lines in the X-ray patterns of the crystalline material of the invention
may exhibit significant variations in relative intensity from the
values indicated in Tables 4 and 5.
[0044] To generate the as-calcined X-ray data listed in Table 5
about 0.5 grams of the dried, as-synthesized crystalline material
are heated in an oven from room temperature under a flow of nitrogen
at a rate of 10.degree. C./minute to 400.degree. C. and, while retaining
the nitrogen flow, the sample is held at 400.degree. C. for 30 minutes.
The nitrogen flow is then ceased and air is passed over the sample
while the temperature of the oven is raised at a rate of 10.degree.
C./minute to 600.degree. C. The sample is then retained at 600.degree.
C. for 2 hours under air, whereafter the oven is cooled to room
temperature to allow the XRD pattern to be recorded.
[0045] The XRD patterns of Tables 4 and 5 can be indexed to a monoclinic
unit cell, in the space group C2/c (#15), having the following unit
cell dimensions in mn: [0046] As-synthesized: a=2.069 b=1.389
c=0.708 .beta.=99.2.degree.; [0047] As-calcined: a=2.255 b=1.374
c=0.719 .beta.=98.61.degree..
[0048] In a preferred embodiment, EMM-8 comprises at least [AlO.sub.4]
and [PO.sub.4] corner sharing tetrahedral units and, in its as-synthesized,
anhydrous form, is represented by the empirical formula: mR:F.sub.a:(M.sub.xAl.sub.yP.sub.z)O.sub.2
wherein R represents at least one directing agent, preferably an
organic directing agent and most preferably 4-dimethylaminopyridine;
m is the number of moles of R per mole of (M.sub.xAl.sub.yP.sub.z)O.sub.2
and m has a value from 0 to 1 such as from 0.1 to about 0.5 preferably
from 0.1 to about 0.3; wherein F represents fluoride ion which may
be present in the synthesis mixture, a is the number of moles of
F per mole of (M.sub.xAl.sub.yP.sub.z)O.sub.2 and a/y is less than
0.25 and preferably is 0; wherein x, y, and z represent the mole
fraction of M, Al and P as tetrahedral oxides; and wherein M is
a metal selected from one of Groups 1 to 14 and Lanthanoids of the
Periodic Table of Elements. Preferably M is selected from B, Co,
Cr, Cu, Fe, Ga, Ge, Mg, Mn, Ni, Si, Sn, Ti, Zn and Zr. Most preferably,
M is silicon.
[0049] In one embodiment, x is from 0 to about 0.25 y is from
about 0.3 to about 0.7 and z is from about 0.25 to about 0.7. In
another embodiment x is from about 0 to about 0.15 y is from about
0.4 to about 0.6 and z is from about 0.3 to about 0.6. In yet another
embodiment x is from about 0 to about 0.12 y is from about 0.45
to about 0.55 and z is from about 0.35 to about 0.55. For ALPO molecular
sieves, x is zero.
[0050] In its calcined form, the large pore (metallo) aluminophosphate
of the present invention typically has an alpha value of at least
0.1 and more preferably at least 0.5 indicating that the material
is useful as an acid catalyst in organic, and in particular hydrocarbon
conversion reactions. The alpha value test is a measure of the cracking
activity of a catalyst and is described in U.S. Pat. No. 3354078
and in the Journal of Catalysis, Vol. 4 p. 527 (1965); Vol. 6
p. 278 (1966); and Vol. 61 p. 395 (1980), each incorporated herein
by reference as to that description. The experimental conditions
of the test used herein include a constant temperature of 538.degree.
C. and a variable flow rate as described in detail in the Journal
of Catalysis, Vol. 61 p. 395.
[0051] The crystalline (metallo)aluminophosphate material of the
present invention can be produced from a synthesis mixture containing
water, a source of phosphorus, a source of aluminum, optionally
a source of metal M, such as silicon, optionally a source of fluoride
ions and 4-dimethylaminopyridine (R). The synthesis mixture typically
has a composition, expressed in terms of mole ratios of oxides,
as follows: TABLE-US-00006 Component Useful Preferred P.sub.2O.sub.5:Al.sub.2O.sub.3
0.7 to 1.3 0.9 to 1.1 SiO.sub.2:Al.sub.2O.sub.3 0 to 0.9 0.05 to
0.5 H.sub.2O:Al.sub.2O.sub.3 10 to 100 20 to 50 R:Al.sub.2O.sub.3
0.5 to 5.0 1.0 to 4.0 F:Al.sub.2O.sub.3 0 to <0.75 0 to 0.5
[0052] A suitable source of phosphorus in the above mixture is
phosphoric acid. Examples of suitable aluminum sources include hydrated
aluminum oxides such as boehmite and pseudoboehmite. Suitable sources
of silicon include silicates, e.g., fumed silica, such as Aerosil
and Cabosil, tetraalkyl orthosilicates, and aqueous colloidal suspensions
of silica, for example that sold by E.I. du Pont de Nemours under
the tradename Ludox.
[0053] If present, the source of fluoride ions may be any compound
capable of releasing fluoride ions in the synthesis mixture. Non-limiting
examples of such sources of fluoride ions include salts containing
one or several fluoride ions, such as metal fluorides, preferably,
sodium fluoride, potassium fluoride, calcium fluoride, magnesium
fluoride, strontium fluoride, barium fluoride, ammonium fluoride,
tetraalkylammonium fluorides, such as tetramethylammonium fluoride,
tetraethylammonium fluoride, hydrogen fluoride, and mixtures thereof.
The preferred source of fluoride is hydrogen fluoride but, more
preferably, the synthesis is conducted in the absence of added fluoride,
that is with the F: Al.sub.2O.sub.3 molar ratio being zero.
[0054] Crystallization is carried out under either stirred or static
conditions, preferably stirred conditions, at a temperature between
about 100.degree. C. and about 250.degree. C., typically between
about 150.degree. C. and about 200.degree. C., preferably between
about 155.degree. C. and about 180.degree. C. Preferably, crystallization
is conducted for about 2 to about 150 hours, preferably about 20
to about 100 hours, whereafter the resultant crystalline material
is separated from the mother liquor and recovered, such as by centrifugation
or filtration. The separated product can also be washed, recovered
by centrifugation or filtration and dried. The crystalline product
is typically in the form of platelets having a d.sub.50 (50% by
volume of crystals is smaller than the d.sub.50 value) particle
size less than 1 .mu.m.
[0055] Synthesis of the large pore (metallo)aluminophosphate material
of the invention may be facilitated by the presence of at least
0.1 ppm, such as at least 10 ppm, for example at least 100 ppm,
conveniently at least 500 ppm of seed crystals from a previous synthesis
based on total weight of the reaction mixture. It is, however, found
that where seed crystals of a CHA framework-type molecular sieve,
such as SAPO-34 are added to the synthesis mixture, the resultant
product is a CHA framework-type molecular sieve rather than the
large pore (metallo)aluminophosphate material of the invention.
[0056] As a result of the crystallization process, the recovered
crystalline product contains within its pores at least a portion
of the organic directing agent used in the synthesis. In a preferred
embodiment, activation is performed in such a manner that the organic
directing agent is removed from the molecular sieve, leaving active
catalytic sites within the microporous channels of the molecular
sieve open for contact with a feedstock. The activation process
is typically accomplished by calcining, or essentially heating the
molecular sieve comprising the template at a temperature of from
about 200.degree. C. to about 800.degree. C., typically in the presence
of an oxygen-containing gas. This type of process can be used for
partial or complete removal of the organic directing agent from
the intracrystalline pore system.
[0057] Once the crystalline material of the invention has been
synthesized, it can be formulated into a catalyst composition by
combination with other materials, such as binders and/or matrix
materials, that provide additional hardness or catalytic activity
to the finished catalyst.
[0058] Materials which can be blended with the crystalline material
of the invention can be various inert or catalytically active materials.
These materials include compositions such as kaolin and other clays,
various forms of rare earth metals, other non-zeolite catalyst components,
zeolite catalyst components, alumina or alumina sol, titania, zirconia,
quartz, silica or silica sol, and mixtures thereof. These components
are also effective in reducing overall catalyst cost, acting as
a thermal sink to assist in heat shielding the catalyst during regeneration,
densifying the catalyst and increasing catalyst strength. When blended
with such components, the amount of crystalline material contained
in the final catalyst product ranges from 10 to 90 weight percent
of the total catalyst, preferably 20 to 80 weight percent of the
total catalyst.
[0059] The large pore crystalline material described herein can
be used to dry gases and liquids; for selective molecular separation
based on size and polar properties; as an ion-exchanger; as a catalyst
in organic conversion reactions, such as cracking, hydrocracking,
disproportionation, alkylation, isomerization, oxidation and synthesis
of monoalkylamines and dialkylamines; as a chemical carrier; in
gas chromatography; and in the petroleum industry to remove normal
paraffins from distillates. Where the synthesis method of the invention
produces a CHA framework-type molecular sieve, such a product would
have similar uses and in particular would be useful as a catalyst
in the conversion of oxygenates, such as methanol, to olefins, such
as ethylene and propylene.
[0060] In order to more fully illustrate the nature of the invention
and the manner of practising same, the following examples are presented.
EXAMPLE 1
[0061] The following ingredients were mixed, in sequence, and blended
into a uniform gel using a microhomogenizer (Tissue Tearor Model
98730 available from Biospec Products, Inc, USA): 85 wt % H.sub.3PO.sub.4
(obtained from Aldrich Chemical Company), deionized H.sub.2O, Catapal.TM.
A (73.9 wt % Al.sub.2O.sub.3 available from CONDEA Vista Company,
Texas, USA), and then 4-dimethylaminopyridine (4-DMAPy) (obtained
from Aldrich Chemical Company, USA). The molar ratio of the ingredients
was as follows: 2.0DMAPy:1.0Al.sub.2O.sub.3:1.0 P.sub.2O.sub.5:40H.sub.2O
[0062] The gel was then placed into a Parr bomb with Teflon liner,
and was heated to 170.degree. C. for 2 to 4 days while the bomb
was tumbled at 40 rpm. The solid product was centrifuged and washed
five times with deionized water, and was then dried in a 60.degree.
C. vacuum oven overnight. X-ray powder patterns of the product showed,
in FIG. 2 that a crystalline product was obtained after two days
of crystallization (Sample A). After four days of crystallization,
additional diffraction peaks corresponding to an unidentified impurity
appeared.
[0063] Solid product yield of Sample A was 13.2%, based on the
total weight of the starting gel. Elemental analysis gave the following
results: Al, 16.0%; P, 17.9%. These results correspond to Al.sub.1.0P.sub.0.975
in composition and 71.2% for calculated total oxides. The residual
weight was separately determined with TGA (Thermal Gravimetric Analysis)
to be 72.6%. Sample A gave the scanning electron micrograph shown
in FIG. 4 and had an XRD pattern with the peaks listed Table 6 below.
TABLE-US-00007 TABLE 6 2.theta. d, nm I % 7.58 1.165 40 8.26 1.070
34 12.66 0.699 64 13.94 0.635 55 14.18 0.624 100 15.18 0.583 8 18.94
0.468 68 19.18 0.462 49 19.60 0.453 66 20.16 0.440 22 20.64 0.430
21 22.88 0.388 15 23.14 0.384 12 25.19 0.353 6 25.48 0.349 37 25.62
0.347 46 25.94 0.343 86 26.12 0.341 39 26.88 0.331 11 27.24 0.327
21 28.08 0.318 26 28.60 0.312 9 29.18 0.306 9 29.32 0.304 19 30.48
0.293 8 30.64 0.292 12 30.98 0.288 14 32.42 0.276 7 34.32 0.261
8 34.72 0.258 22 35.24 0.254 12 36.04 0.249 8
[0064] The powder pattern of Sample A was indexed successfully
in a monoclinic unit cell, in the Space Group C2/c (#15). The unit
cell dimensions in nm are a=2.069 b=1.389 c=0.708 .beta.=99.2.degree..
EXAMPLE 2
[0065] The procedure was identical to Example 1 except that hydrofluoric
acid was added as the last ingredient and the ingredient ratio was
the following: 0.5HF:2.0DMAPy:1.0Al.sub.2O.sub.3:1.0P.sub.2O.sub.5:40H.sub.2O
[0066] The crystallization was carried out for three days at 180.degree.
C. statically. The product yield was 12.9 wt %. The XRD pattern
of the product (Sample B) is shown in FIG. 3 along with that of
Sample A. The former is nearly identical to that of Sample A, although
the peak width and relative intensity are somewhat different. The
relative peak intensity difference is expected with the presence
of F in Sample B. The broader peaks of Sample B are possibly due
to the small platelet (<0.1 .mu.m) morphology of the crystals
as shown by a Scanning Electron Microscope micrograph (see FIG.
4).
[0067] The fact that the same crystalline product was obtained
with different starting synthesis compositions (Examples 1 and 2),
and that the XRD patterns of the products can be indexed establish
that a pure phase material has been synthesized. The as-synthesized
material has a unique XRD pattern.
EXAMPLE 3
[0068] The procedure of Example 1 was repeated to produce two additional
samples, Samples C and D, except that Cabosil.TM. silica was added
to each synthesis mixture after the Catapal.TM. alumina and before
4-dimethylaminopyridine. The ingredient molar ratios were as follows:
2.0DMAPy:1.0Al.sub.2O.sub.3:(0.1& 0.3)SiO.sub.2:1.0P.sub.2O.sub.5:40H.sub.2O
[0069] To the synthesis gel 0.15wt % Sample B was added as seeds.
The crystallization was carried out for two days at 170.degree.
C. with tumbling at 40 rpm. The product yield was 18.9 and 19.6
wt %, for 0.1 SiO.sub.2 and 0.3 SiO.sub.2 respectively. The XRD
patterns of the products (Samples C and D for 0.1 and 0.3 SiO.sub.2
respectively) are shown in FIG. 5 along with that of Sample A. This
Figure, along with the elemental analysis results below, shows that
silicon atoms can be incorporated into the framework of Sample A.
[0070] Elemental analysis results were as follows: Sample C: Al=16.1%;
P=16.9%; Si=2.38%. This corresponds to Al.sub.1.0Si.sub.0.058P.sub.0.914
in composition and 71.2% for calculated total oxides. Sample D:
Al=14.8%; P=15.7%; Si=2.38%. This corresponds to Al.sub.1.0Si.sub.0.154P.sub.0.924
in composition and 69.1% for calculated total oxides.
[0071] The powder pattern of Sample C was indexed successfully
in the same monoclinic unit cell as Sample A, in the Space Group
C2/c(#15). The unit cell dimensions in nm are: a=2.169 b=1.386
c=0.705 .beta.=98.9.degree.. The unit cell volume is 2.0983 nm.sup.3.
These unit cell parameters are similar to those of Sample A.
EXAMPLE 4
[0072] Calcination of the samples A, C and D (10.degree. C./min
to 400.degree. C. in nitrogen, then dwell for 30 minutes in nitrogen
before ramping to 600.degree. C. at 10.degree. C./min in air, and
finally dwell at 600.degree. C. for 2 hours in air) resulted in
white crystalline products with the organic directing agent removed.
The XRD patterns of the calcined samples, taken in ambient air so
there may be some degree of rehydration, are shown in FIG. 6 along
with that of the as-synthesized Sample A.
[0073] All three samples gave different XRD patterns from their
as-synthesized counterparts. The calcined Sample A, being an AlPO.sub.4
shows a different pattern from those of the calcined Samples C and
D. The latter two, both being SAPOs, have similar XRD patterns.
A similar phenomenon has been found in AlPO.sub.4 and SAPOs having
the CHA framework type. AlPO.sub.4-34 for example, adopts a triclinic
unit cell when exposed to moisture, whereas SAPO-34s having sufficiently
high Si levels retain their rhombohedral symmetry after rehydration.
[0074] The XRD pattern of calcined Sample C was indexed in a monoclinic
unit cell similar to that for the as-synthesized sample. The unit
cell constants in nm are a=2.233 b=1.336 c=0.716 .beta.=99.88.degree..
The unit cell volume is 2.1050 nm.sup.3. These unit cell parameters
are very similar to those of as-synthesized Sample C, with only
about 0.3% increase in unit cell volume upon calcination.
EXAMPLE 5
[0075] Calcination of Sample C was conducted and XRDs were taken
on a platinum sample stage that was enclosed in a chamber equipped
with different sources of inert and reactive gases. The platinum
sample stage also served as an XRD sample holder so that XRD patterns
could be taken at different temperatures as well as under different
atmospheres. First a pattern was taken on the as-synthesized Sample
C. Then, after a ramp in temperature at 10.degree. C./min to 600.degree.
C. and dwelling at the temperature for two hours under a flow of
dry air (15 ppm moisture), and cooling to 200.degree. C., a second
XRD pattern was taken. The flowing gas was switched to N.sub.2 and
the sample was cooled to room temperature before a third XRD pattern
was taken in N.sub.2. Afterwards the chamber was opened to the ambient
air, which had a relative humidity of 82% (22.degree. C.), for 16
hours, to ensure that the sample was fully hydrated. A fourth XRD
pattern was then taken. Finally, the chamber was closed again, and
the temperature was raised to 200.degree. C. under N.sub.2 to dehydrate
the sample. A final fifth XRD pattern was taken at 200.degree. C.
in N.sub.2.
[0076] The results are shown in FIG. 7 and indicate that calcination
results in some change in the XRD pattern as well as an increase
in the overall diffraction intensity. Exposure to moisture reduces
the diffraction intensity to the pre-calcination level, and the
XRD pattern is again slightly changed. Then dehydration of the hydrated
sample leads to an XRD pattern identical to that of the post-calcination
sample, indicating the hydration process is at least partially reversible.
EXAMPLE 6
[0077] Calcined (600.degree. C. for two hours) and degassed (at
500.degree. C.) Sample A was exposed to different adsorbate molecules
under specified conditions as listed in Table 7 below in a Thermal
Gravimetric Analysis (TGA) unit. In all cases complete adsorption
was attained. The diffusivity number D/r.sup.2 given in Table 7
was obtained by analyzing the initial portion of the adsorption
uptake curve. In all cases adsorption was found to be too fast for
accurate determination of diffusivity. Therefore the numbers reported
are the best estimates. Table 7 also provides, for comparison purposes,
some adsorption data for the 10.times.10.times.9 ring material ITQ-13.
TABLE-US-00008 TABLE 7 22- Adsorbate Methanol n-Hexane Dimethylbutane
Mesitylene Sample A Ads. 35.degree. C., 90.degree. C., 120.degree.
C., 90 torr 100.degree. C., Conditions 203 torr 75 torr 2 torr Ads.
Capacity, 20.1 9.61 7.44 11.02 wt % D/r.sup.2 sec.sup.-1 0.066
0.1 0.01 ITQ-13 (For Comparison) Ads. Capacity, 7.60 5.40 0 wt %
D/r.sup.2 sec.sup.-1 0.1
[0078] The significant amount of mesitylene adsorption indicates
that the new material has pore openings larger or equal to 0.7 nm
(7 .ANG.)(12-ring), and the large adsorption capacity suggests that
the framework is very open.
EXAMPLE 7
[0079] Samples C and D, having Si/Al ratio of 0.058 and 0.154
respectively, were calcined at 600.degree. C. for 2 hours before
n-hexane cracking test was conducted. The standard .alpha.-test
conditions (538.degree. C.) were used. The .alpha.-numbers for these
two samples were determined to be 9.1 and 23.3 respectively. These
values show that the new material has potential for hydrocarbon
conversion applications.
EXAMPLE 8
[0080] The synthesis procedure was identical to Example 1 except
that Cabosil.TM. was added after Catapal.TM. and before 4-dimethylaminopyridine,
and 100 ppm colloidal SAPO-34 seeds were added as the last ingredient.
The ingredient ratio was as follows: 2.0DMAPy:1.0Al.sub.2O.sub.3:0.3SiO.sub.2:1.0P.sub.2O.sub.5:40H.sub.2O
[0081] Crystallization was carried out for two and four days at
170.degree. C. with tumbling at 40 rpm. The solid yields for two
and four days of crystallization were 17.85% and 21.07%, respectively.
[0082] The XRD patterns are shown in FIG. 8 which shows that SAPO-34
has been made, although impurities were present. The product of
two-day crystallization had trace amount of AFI (AlPO.sub.4-5) and
what appeared to be AWO AlPO.sub.4-21), while that of four-day crystallization
had no AFI but an increased of AWO.
[0083] While the present invention has been described and illustrated
by reference to particular embodiments, those of ordinary skill
in the art will appreciate that the invention lends itself to variations
not necessarily illustrated herein. For this reason, then, reference
should be made solely to the appended claims for purposes of determining
the true scope of the present invention. |