Molecular sieve abstract
A crystalline material substantially free of framework phosphorus
and comprising a CHA framework type molecular sieve with stacking
faults or at least one intergrown phase of a CHA framework type
molecular sieve and an AEI framework type molecular sieve, wherein
said material, in its calcined, anhydrous form, has a composition
involving the molar relationship: (n)X.sub.2O.sub.3:YO.sub.2 wherein
X is a trivalent element; Y is a tetravalent element; and n is from
0 to about 0.5. The material exhibits activity and selectivity in
the conversion of methanol to lower olefins, especially ethylene
and propylene.
Molecular sieve claims
We claim:
1. A crystalline material substantially free of framework phosphorus
and comprising a CHA framework type molecular sieve with stacking
faults or at least one intergrown phase of a CHA framework type
molecular sieve and an AEI framework type molecular sieve, wherein
said material, in its calcined, anhydrous form, has a composition
involving the molar relationship: (n)X.sub.2O.sub.3:YO.sub.2 wherein
X is a trivalent element; Y is a tetravalent element; and n is from
0 to about 0.5.
2. The crystalline material of claim 1 wherein n is from about
0.001 to about 0.1.
3. The crystalline material of claim 1 wherein n is from about
0.0017 to about 0.02.
4. The crystalline material of claim 1 wherein said material, in
its calcined form, contains from about 1 to about 100 ppm by weight
of a halide.
5. The crystalline material of claim 1 wherein said material, in
its calcined form, contains from about 5 to about 50 ppm by weight
of a halide.
6. The crystalline material of claim 1 wherein said material, in
its calcined form, contains from about 10 to about 20 ppm, by weight
of a halide.
7. The crystalline material of claim 4 wherein said halide comprises
fluoride.
8. The crystalline material of claim 1 wherein Y is silicon, tin,
titanium germanium or a combination thereof.
9. The crystalline material of claim 1 wherein Y is silicon.
10. The crystalline material of claim 1 wherein X is aluminum,
boron, iron, indium, gallium or a combination thereof.
11. The crystalline material of claim 1 wherein X is aluminum.
12. A crystalline material which comprises at least a CHA framework
type molecular sieve and which, in its as-synthesized form, contains
in its intra-molecular framework a first directing agent for directing
the synthesis of a CHA framework-type molecular sieve and a second
directing agent for directing the synthesis of a AEI framework-type
molecular sieve, said first and second directing agents being different.
13. The crystalline material of claim 12 wherein the first directing
agent comprises a multi-cyclic amine or ammonium compound.
14. The crystalline material of claim 12 wherein the first directing
agent comprises a tricyclic or tetracyclic amine or ammonium compound.
15. The crystalline material of claim 12 wherein the first directing
agent comprises at least one of an N-alkyl-3-quinuclidinol, an N,N,N-trialkyl-exoaminonorbornane,
an N,N,N-trimethyl-1-adamantammonium compound, an N,N,N-trimethyl-2-adamantammonium
compound, an N,N,N-trimethylcyclohexylammonium compound, an N,N-dimethyl-33-dimethylp-
iperidinium compound, an N,N-methylethyl-33-dimethylpiperidinium
compound, an N,N-dimethyl-2-methylpiperidinium compound, a 13366-pentamethyl-6-azonio-bicyclo(3.2.1)octane
compound and N,N-dimethylcyclohexylamine.
16. The crystalline material of claim 12 wherein the first directing
agent comprises an N,N,N-trimethyl-1-adamantyl ammonium compound.
17. The crystalline material of claim 12 wherein the second directing
agent comprises a monocyclic amine or ammonium compound.
18. The crystalline material of claim 12 wherein the second directing
agent comprises a substituted piperidine or piperidinium compound.
19. The crystalline material of claim 12 wherein the second directing
agent comprises a tetraalkylpiperidinium compound.
20. The crystalline material of claim 12 wherein the second directing
agent comprises an N,N-dimethyl-26-dimethylpiperidinium compound
or an N,N-diethyl-26-dimethylpiperidinium compound.
21. The crystalline material of claim 12 wherein the molar amount
of second directing agent retained in the as-synthesized material
to the total molar amount of first and second directing agents retained
in the as-synthesized material is between 0.1 and 0.3.
22. The crystalline material of claim 12 wherein said material
is substantially free of framework phosphorus.
23. A method of synthesizing a crystalline material comprising
a CHA framework type molecular sieve and having a composition involving
the molar relationship: (n)X.sub.2O.sub.3:YO.sub.2 wherein X is
a trivalent element; Y is a tetravalent element; and n is from 0
to about 0.5 the method comprising: (a) preparing a reaction mixture
capable of forming said material, said mixture comprising a source
of water, a source of an oxide of a tetravalent element Y and optionally
a source of an oxide of a trivalent element X; (b) maintaining said
reaction mixture under conditions sufficient to form crystals of
said crystalline material comprising stacking faults or at least
one intergrown phase of a CHA framework type molecular sieve and
an AEI framework type molecular sieve; and (c) recovering said crystalline
material from (b).
24. The method of claim 23 wherein said reaction mixture also comprises
at least one organic directing agent (R) for directing the formation
of said crystalline material.
25. The method of claim 23 wherein said reaction mixture also comprises
a plurality of different organic directing agents for directing
the formation of said crystalline material.
26. The method of claim 23 wherein said reaction mixture comprises
at least one first organic directing agent for directing the formation
of a CHA framework type material and at least one second organic
directing agent for directing the formation of an AEI framework
type material.
27. The method of claim 26 wherein the first directing agent comprises
a multi-cyclic amine or ammonium compound.
28. The method of claim 26 wherein the first directing agent comprises
a tricyclic or tetracyclic amine or ammonium compound.
29. The method of claim 26 wherein the first directing agent comprises
at least one of an N-alkyl-3-quinuclidinol, an N,N,N-trialkyl-exoaminonorbor-
nane, an N,N,N-trimethyl-1-adamantammonium compound, an N,N,N-trimethyl-2-adamantammonium
compound, an N,N,N-trimethylcyclohexyla- mmonium compound, an N,N-dimethyl-33-dimethylpiperidinium
compound, an N,N-methylethyl-33-dimethylpiperidinium compound,
an N,N-dimethyl-2-methylpiperidinium compound, a 13366-pentamethyl-6-azo-
nio-bicyclo(3.2.1)octane compound and N,N-dimethylcyclohexylamine.
30. The method of claim 26 wherein the first directing agent comprises
an N,N,N-trimethyl-1-adamantylammonium compound.
31. The method of claim 26 wherein the second directing agent
comprises a monocyclic amine or ammonium compound.
32. The method of claim 26 wherein the second directing agent
comprises a substituted piperidine or piperidinium compound.
33. The method of claim 26 wherein the second directing agent
comprises a tetraalkylpiperidinium compound.
34. The method of claim 26 wherein the second directing agent
comprises an N,N-dimethyl-26-dimethylpiperidinium compound or an
N,N-diethyl-26-dimethylpiperidinium compound.
35. The method of claim 26 wherein the molar ratio of the first
organic directing agent to the second organic directing agent in
the reaction mixture is between about 0.01 and about 100.
36. The method of claim 23 wherein said reaction mixture also
comprises a halide or a halide-containing compound.
37. The method of claim 23 wherein said reaction mixture also
comprises a fluoride or fluoride-containing compound.
38. The method of claim 23 wherein the conditions in (b) include
a temperature of from about 50.degree. C. to about 300.degree. C.
39. The method of claim 23 wherein the conditions in (b) include
a temperature of from about 135.degree. C. to about 185.degree.
C.
40. The method of claim 23 wherein said reaction mixture also
comprises seed crystals.
41. The method of claim 40 wherein said seed crystals are added
to said reaction mixture as a colloidal suspension in a liquid medium.
42. The method of claim 40 wherein said seed crystals are homostructural
with said crystalline material comprising at least one intergrown
phase of a CHA framework type and an AEI framework type.
43. The method of claim 40 wherein said seed crystals comprise
a crystalline material having an AEI, OFF, CHA or LEV framework-type.
44. The method of claim 40 wherein said seed crystals comprise
a crystalline material having an AEI framework type.
45. The method of claim 24 wherein said reaction mixture has the
following molar composition:
9 H.sub.2O/YO.sub.2 0.1 to 20 Halide/YO.sub.2 0 to 2 R/YO.sub.2
0.01 to 2; X.sub.2O.sub.3/YO.sub.2 0 to 0.5.
46. The method of claim 24 wherein said reaction mixture has the
following molar composition:
10 H.sub.2O/YO.sub.2 2 to 10; Halide/YO.sub.2 0.01 to 1; R/YO.sub.2
0.1 to 1; X.sub.2O.sub.3/YO.sub.2 0 to 0.1.
47. A method of synthesizing a crystalline material comprising
at least a CHA framework type molecular sieve and comprising YO.sub.2
wherein Y is a tetravalent element, and optionally X.sub.2O.sub.3
wherein X is a trivalent element, the method comprising: (a) preparing
a reaction mixture comprising a source of water, a source of the
tetravalent element Y, optionally a source of the trivalent element
X, and an organic directing agent (R) comprising at least one first
organic directing agent for directing the formation of a CHA framework
type material and at least one second organic directing agent for
directing the formation of an AEI structure type material, said
first and second directing agents being different; (b) maintaining
said reaction mixture under conditions sufficient to form crystals
of said material; and (c) recovering said crystalline material from
step (b).
48. The method of claim 47 wherein the crystalline material comprises
a composition involving the molar relationship: (n)X.sub.2O.sub.3:YO.sub.2
wherein n is from 0 to about 0.5.
49. A process for producing olefins comprising the step of contacting
an organic oxygenate compound under oxygenate conversion conditions
with a catalyst comprising a porous crystalline material substantially
free of framework phosphorus and comprising a CHA framework type
molecular sieve with stacking faults or at least one intergrown
phase of a CHA framework type molecular sieve and an AEI framework
type molecular sieve, wherein said material, in its calcined, anhydrous
form, has a composition involving the molar relationship: (n)X.sub.2O.sub.3:YO.sub.2
wherein X is a trivalent element; Y is a tetravalent element; and
n is from 0 to about 0.5.
50. The process of claim 49 wherein n is from about 0.001 to about
0.1.
51. The process of claim 49 wherein wherein n is from about 0.0017
to about 0.02.
52. The process of claim 49 wherein said organic oxygenate compound
comprises methanol, dimethyl ether or a mixture thereof.
Molecular sieve description
trimethyladamantylammoniu- m in hydroxide form as the structure-directing
agent at nearly neutral pH in the presence of fluoride. See Diaz-Cabanas,
M-J, Barrett, P. A., and Camblor, M. A. "Synthesis and Structure
of Pure SiO.sub.2 Chabazite: the SiO.sub.2 Polymorph with the Lowest
Framework Density", Chem. Commun. 1881 (1998).
[0010] More recently, an aluminosilicate with the CHA framework
type and having a silica to alumina molar ratio in excess of 100
such as from 150 to 2000 has been synthesized again in the presence
of fluoride ions. See U.S. Patent Application Publication No. 2003/0176751
published Sep. 18 2003 and incorporated herein by reference.
[0011] Molecular sieves of the AEI framework-type do not exist
in nature. However, a number of aluminophosphates and silicoaluminophosphates
having the AEI framework type have been synthesized, including SAPO-18
ALPO-18 and RUW-18. In addition, U.S. Pat. No. 5958370 incorporated
herein by reference, discloses an aluminosilicate zeolite having
an AEI framework-type and a silica to alumina molar ratio of 10
to 100. Aluminosilicates having a silica to alumina ratio greater
than 100 and all-silica molecular sieves with an AEI framework-type
have so far not been reported.
[0012] Regular crystalline molecular sieves, such as the AEI and
CHA framework types, are built from structurally invariant building
units, called Periodic Building Units, and are periodically ordered
in three dimensions. However, disordered structures showing periodic
ordering in less than three dimensions are also known. One such
disordered structure is a disordered planar intergrowth in which
the repeated building units from more than one framework type, e.g.,
both AEI and CHA, are present. In addition, for certain molecular
sieves, the building units can exist in mirror image forms, which
can result in stacking faults where a sequence of building units
of one mirror image form intersects a sequence of building units
of the opposite mirror image form.
[0013] U.S. Pat. No. 6334994 incorporated herein by reference,
discloses a silicoaluminophosphate molecular sieve, referred to
as RUW-19 which is said to be an AEI/CHA mixed phase composition.
In particular, RUW-19 is reported as having peaks characteristic
of both CHA and AEI framework type molecular sieves, except that
the broad feature centered at about 16.9 (2.theta.) in RUW-19 replaces
the pair of reflections centered at about 17.0 (2.theta.) in AEI
materials and RUW-19 does not have the reflections associated with
CHA materials centered at 2.theta. values of 17.8 and 24.8.
[0014] U.S. Patent Application Publication No. 2002/0165089 published
Nov. 7 2002 and incorporated herein by reference, discloses a silicoaluminophosphate
molecular sieve comprising at least one intergrown phase of molecular
sieves having AEI and CHA framework types, wherein said intergrown
phase has an AEI/CHA ratio of from about 5/95 to 40/60 as determined
by DIFFaX analysis, using the powder X-ray diffraction pattern of
a calcined sample of said silicoaluminophosphate molecular sieve.
[0015] Phosphorus-free molecular sieves, such as aluminosilicates
and silicas, comprising CHA/AEI intergrowths have so far not been
reported.
SUMMARY
[0016] In one aspect, the invention resides in a crystalline material
substantially free of framework phosphorus and comprising a CHA
framework type molecular sieve with stacking faults or at least
one intergrown phase of a CHA framework type molecular sieve and
an AEI framework type molecular sieve, wherein said material, in
its calcined, anhydrous form, has a composition involving the molar
relationship:
(n)X.sub.2O.sub.3:YO.sub.2
[0017] wherein X is a trivalent element, such as aluminum, boron,
iron, indium, and/or gallium; Y is a tetravalent element such as
silicon, tin, titanium and/or germanium; and n is from 0 to about
0.5 conveniently from 0 to about 0.125 for example from about
0.001 to about 0.1 such as from about 0.0017 to about 0.02.
[0018] Conveniently, the calcined crystalline material contains
from about 1 to about 100 ppm, for example from about 5 to about
50 ppm, such as from about 10 to about 20 ppm, by weight of a halide,
preferably fluoride.
[0019] In a further aspect, the invention resides in a crystalline
material which comprises at least a CHA framework type molecular
sieve and which, in its as-synthesized form, contains in its intra-molecular
structure a first directing agent for directing the synthesis of
a CHA framework-type molecular sieve and a second directing agent
for directing the synthesis of a AEI framework-type molecular sieve,
said first and second directing agents being different.
[0020] In one embodiment, each of the first and second directing
agents comprises a cyclic amine or ammonium compound. More particularly,
the first directing agent comprises a multi-cyclic amine or ammonium
compound and the second directing agent comprises a monocyclic amine
or ammonium compound. Conveniently, the multi-cyclic amine or ammonium
compound comprises a tricyclic or tetracyclic amine or ammonium
compound, such as at least one of an N-alkyl-3-quinuclidinol, an
N,N,N-trialkyl-exoaminonor- bornane and an adamantylamine or ammonium
compound, for example an N,N,N-trialkyl-1-adamantylammonium compound;
typically an N,N,N-trimethyl-1-adamantylammonium compound. Conveniently,
the monocyclic amine or ammonium compound comprises a substituted
piperidine or piperidinium compound, for example a tetraalkylpiperidinium
compound, typically an N,N-diethyl-26-dimethylpiperidinium compound.
[0021] In yet a further aspect, the invention resides in a method
of synthesizing a crystalline material comprising a CHA framework
type molecular sieve and having a composition involving the molar
relationship:
(n)X.sub.2O.sub.3:YO.sub.2
[0022] wherein X is a trivalent element, Y is a tetravalent element
and n is from 0 to about 0.5 the method comprising:
[0023] (a) preparing a reaction mixture capable of forming said
material, said mixture comprising a source of water, a source of
an oxide of a tetravalent element Y, and optionally a source of
an oxide of a trivalent element X;
[0024] (b) maintaining said reaction mixture under conditions sufficient
to form crystals of said crystalline material comprising stacking
faults or at least one intergrown phase of a CHA framework type
molecular sieve and an AEI framework type molecular sieve; and
[0025] (c) recovering said crystalline material from (b).
[0026] Conveniently, said reaction mixture also comprises a halide
or a halide-containing compound, such as a fluoride or a fluoride-containing
compound.
[0027] Conveniently, said reaction mixture also comprises a first
directing agent for directing the synthesis of a CHA framework-type
molecular sieve and a second directing agent for directing the synthesis
of a AEI framework-type molecular sieve.
[0028] Conveniently, said reaction mixture also comprises seed
crystals. The seed crystals can be homostructural or heterostructural
with said intergrown phase. In one embodiment, the seed crystals
comprise a crystalline material having an AEI, CHA, OFF or LEV framework-type.
[0029] In still a further aspect, the invention resides in a process
for producing olefins comprising the step of contacting an organic
oxygenate compound under oxygenate conversion conditions with a
catalyst comprising a porous crystalline material substantially
free of framework phosphorus and comprising at least one intergrown
phase of a CHA framework type and an AEI framework type.
[0030] It is to be understood that the term "in its calcined,
anhydrous form" is used herein to refer to a material which
has been heated in air at a temperature in excess of 400.degree.
C. for 0.1 to 10 hours without allowing the material to rehydrate.
BRIEF DESCRIPTION OF THE DRAWINGS
[0031] FIGS. 1a and 1b are DIFFaX simulated diffraction patterns
for intergrown CHA/AEI zeolite phases having varying CHA/AEI ratios.
[0032] FIG. 2 is the X-ray diffraction pattern of the calcined
product of Example 1.
[0033] FIG. 3 is an overlay of part of the X-ray diffraction pattern
of FIG. 2 with the DIFFaX simulated trace obtained as the sum of
56% of phase (a), a random intergrown AEI/CHA phase having an AEI/CHA
ratio of 15/85 and 44% of phase (b), a random intergrown AEI/CHA
phase having an AEI/CHA ratio of 75/25. The weighted average AEI/CHA
ratio for example 1 is calculated as 41/59.
[0034] FIG. 4 is a high resolution transmission electron micrograph
of the product of the 175.degree. C. synthesis of Example 2.
[0035] FIG. 5 is a high resolution transmission electron micrograph
of the product of Example 3. The inset is a Fourier Transform of
the high resolution transmission electron micrograph.
[0036] FIG. 6 is a bright-field transmission electron micrograph
of the product of Comparative Example 5.
[0037] FIG. 7 is a bright-field transmission electron micrograph
of the natural chabazite of Comparative Example 6.
[0038] FIG. 8 is the X-ray diffraction pattern of the calcined
product of Example 7.
[0039] FIG. 9 is a high resolution transmission electron micrograph
of the product of Example 7.
DETAILED DESCRIPTION OF THE EMBODIMENTS
[0040] The present invention relates to a novel crystalline material
that is substantially free of framework phosphorus and that comprises
a CHA framework type molecular sieve with stacking faults or at
least one intergrown phase of a CHA framework type molecular sieve
and an AEI framework type molecular sieve. The invention also relates
to the synthesis of this novel crystalline material in a halide,
and particularly a fluoride, medium and to use of the material,
such as in a process for the conversion of oxygenates, particularly
methanol, to olefins, particularly ethylene and propylene.
[0041] Intergrown molecular sieve phases are disordered planar
intergrowths of molecular sieve frameworks. Reference is directed
to the "Catalog of Disordered Zeolite Structures", 2000
Edition, published by the Structure Commission of the International
Zeolite Association and to the "Collection of Simulated XRD
Powder Patterns for Zeolites", M. M. J. Treacy and J. B. Higgins,
2001 Edition, published on behalf of the Structure Commission of
the International Zeolite Association for a detailed explanation
on intergrown molecular sieve phases.
[0042] Regular crystalline solids are built from structurally invariant
building units, called Periodic Building Units, and are periodically
ordered in three dimensions. Structurally disordered structures
show periodic ordering in dimensions less than three, i.e. in two,
one or zero dimensions. This phenomenon is called stacking disorder
of structurally invariant Periodic Building Units. Crystal structures
built from Periodic Building Units are called end-member structures
if periodic ordering is achieved in all three dimensions. Disordered
structures are those where the stacking sequence of the Periodic
Building Units deviates from periodic ordering up to statistical
stacking sequences.
[0043] In the case of regular AEI and CHA framework type molecular
sieves, the Periodic Building Unit is a double six ring layer. There
are two types of layers "a" and "b", which are
topologically identical except "b" is the mirror image
of "a". When layers of the same type stack on top of one
another, i.e. aaaaaaaa or bbbbbbbb, the framework type CHA is generated.
When layers "a" and "b" alternate, ie, abababab,
the framework type AEI is generated. Intergrown AEI/CHA molecular
sieves comprise regions of CHA framework type sequences and regions
of AEI framework type sequences. Each change from a CHA to an AEI
framework type sequence results in a stacking fault. In addition,
stacking faults can occur in a pure CHA phase material when a sequence
of one mirror image layers intersects a sequence of the opposite
mirror image layers, such as for example in aaaaaabbbbbbb.
[0044] Analysis of intergrown molecular sieves, such as AEI/CHA
intergrowths, can be effected by X-ray diffraction and in particular
by comparing the observed patterns with calculated patterns generated
using algorithms to simulate the effects of stacking disorder. DIFFaX
is a computer program based on a mathematical model for calculating
intensities from crystals containing planar faults (see M. M. J.
Tracey et al., Proceedings of the Royal Chemical Society, London,
A [1991], Vol. 433 pp. 499-520). DIFFaX is the simulation program
selected by and available from the International Zeolite Association
to simulate the XRD powder patterns for randomly intergrown phases
of zeolites (see "Collection of Simulated XRD Powder Patterns
for Zeolites" by M. M. J. Treacy and J. B. Higgins, 2001 Fourth
Edition, published on behalf of the Structure Commission of the
International Zeolite Association). It has also been used to theoretically
study intergrown phases of AEI, CHA and KFI, as reported by K. P.
Lillerud et al. in "Studies in Surface Science and Catalysis",
1994 Vol. 84 pp. 543-550.
[0045] FIGS. 1a and 1b show the simulated diffraction patterns
calculated by DIFFaX for single intergrown zeolite phases having
various AEI/CHA ratios. These patterns were calculated using the
input file given in Table 1 below, with each pattern being normalized
to the highest peak of the entire set of simulated patterns, i.e.
the peak at about 9.6 degrees 2.theta. for the 0/100 AEI/CHA pattern.
Normalization of intensity values allows the intensity of an X-ray
diffraction peak at a certain 2.theta. value to be compared between
different diffraction patterns.
[0046] Where the crystalline material of the invention comprises
an intergrowth of a CHA framework type molecular sieve and an AEI
framework type molecular sieve, the material can possess a widely
varying AEI/CHA ratio of from about 99:1 to about 1:99 such as
from about 98:2 to about 2:98 for example from about 95:5 to 5:95.
In one embodiment, where the material is to be used a catalyst in
the conversion of oxygenates to olefins, the intergrowth is preferably
CHA-rich and has AEI/CHA ratio ranging from about 5:95 to about
30:70. In addition, in some cases the intergrown material of the
invention may comprise a plurality of intergrown phases each having
a different AEI/CHA ratio. The relative amounts of AEI and CHA framework-type
materials in the intergrowth of the invention can be determined
by a variety of known techniques including transmission electron
microscopy (TEM) and DIFFaX analysis, using the powder X-ray diffraction
pattern of a calcined sample of the molecular sieve.
[0047] Where the crystalline material of the invention comprises
a CHA framework type molecular sieve but with stacking faults, the
presence of these stacking faults can readily be determined by transmission
electron microscopy. It is to be appreciated that stacking faults
may not be present in every crystal of the CHA material but generally
will be present in at least 5%, such as at least 10%, of the crystals.
[0048] In its calcined and anhydrous form, the crystalline material
of the present invention has a composition involving the molar relationship:
(n)X.sub.2O.sub.3:YO.sub.2
[0049] wherein X is a trivalent element, such as aluminum, boron,
iron, indium, and/or gallium, typically aluminum; Y is a tetravalent
element, such as silicon, tin, titanium and/or germanium, typically
silicon; and n is from 0 to about 0.5 conveniently from 0 to about
0.125 for example from about 0.001 to about 0.1 such as from about
0.0017 to about 0.02. Where a halide-containing compound has been
used in the synthesis of the material, the calcined form of the
material of the present invention is normally found to contain trace
amounts, typically from about 1 to about 100 ppm, for example from
about 5 to about 50 ppm, such as from about 10 to about 20 ppm,
by weight of the halide, preferably fluoride.
[0050] In its as-synthesized form, the crystalline material of
the present invention typically has a composition involving the
molar relationship:
(n)X.sub.2O.sub.3:YO.sub.2:(m)R:(x)F:z H.sub.2O,
[0051] wherein X, Y and n are as defined in the preceding paragraph,
R is at least one organic directing agent and wherein m ranges from
about 0.01 to about 2 such as from about 0.1 to about 1 z ranges
from about 0.5 to about 100 such as from about 2 to about 20 and
x ranges from about 0 to about 2 such as from about 0.01 to about
1. The R and F components, which are associated with the material
as a result of their presence during crystallization, can be at
least partly removed by post-crystallization methods hereinafter
more particularly described. Typically, in its as-synthesized form,
the intergrowth of the present invention contains only low levels
of alkali metal, generally such that the combined amount of any
potassium and sodium is less than 50% of the X.sub.2O.sub.3 on a
molar basis. For this reason, after removal of the organic directing
agent (R), the material generally exhibits catalytic activity without
a preliminary ion-exchange step to remove alkali metal cations.
[0052] As will be discussed below, the least one organic directing
agent (R) typically comprises at least one first organic directing
agent for directing the synthesis of a CHA framework-type material
and at least one second organic directing agent for directing the
synthesis of an AEI framework-type material. It is found that these
directing agents are typically retained intact in the intra-molecular
structure of the molecular sieve product. Depending on the composition
of the directing agents it will normally possible to determine the
relative amounts of the different directing agents retained in the
as-synthesized molecular sieve by analytical techniques, such as
.sup.13C MAS (magic-angle spinning) NMR. Thus, in a preferred embodiment,
where the first organic directing agent is an N,N,N-trimethyl-1-adamantylammonium
compound (TMAA) and the second organic directing agent is an N,N-diethyl-26-dimethylpiperidinium
compound (DEDMP), the DEDMP exhibits peaks corresponding to the
C nuclei in the CH.sub.3 moieties in the 0 to 20 ppm range of the
.sup.13C MAS NMR spectrum, which peaks are not present in the .sup.13C
MAS NMR spectrum of the TMAA. This, by measuring the peak heights
in the 0 to 20 ppm range of the .sup.13C MAS NMR spectrum, the relative
amounts of TMAA and DEDMP in the as-synthesized material can be
determined. Preferably, the molar amount of AEI directing agent
retained in the as-synthesized material to the total molar amount
of AEI and CHA directing agent retained in the as-synthesized material
is between 0.1 and 0.3.
[0053] To the extent desired and depending on the X.sub.2O.sub.3/YO.sub.2
molar ratio of the material, any cations in the as-synthesized intergrowth
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, VIIB, VIIB and VIII of the Periodic Table of the Elements.
[0054] The intergrowth of the invention can be prepared from a
reaction mixture containing a source of water, a source of an oxide
of the tetravalent element Y, optionally a source of an oxide of
the trivalent element X, at least one organic directing agent I
as described below, and typically a halide or a halide-containing
compound, such as a fluoride or a fluoride-containing compound,
said reaction mixture having a composition, in terms of mole ratios
of oxides, within the following ranges:
1 Reactants Useful Typical H.sub.2O/YO.sub.2 0.1 to 20 2 to 10
Halide/YO.sub.2 0 to 2 0.01 to 1 R/YO.sub.2 0.01 to 2 0.1 to 1 X.sub.2O.sub.3/YO.sub.2
0 to 0.5 0 to 0.1
[0055] Where the tetravalent element Y is silicon, suitable sources
of silicon include silicates, e.g., tetraalkyl orthosilicates, fumed
silica, such as Aerosil (available from Degussa), and aqueous colloidal
suspensions of silica, for example that sold by E.I. du Pont de
Nemours under the tradename Ludox. Where the trivalent element X
is aluminum, suitable sources of aluminum include aluminum salts,
especially water-soluble salts, such as aluminum nitrate, as well
as hydrated aluminum oxides, such as boehmite and pseudoboehmite.
Where the halide is fluoride, suitable sources of fluoride include
hydrogen fluoride, although more benign sources of fluoride such
as alkali metal fluorides and fluoride salts of the organic directing
agent are preferred.
[0056] The at least one organic directing agent R used herein conveniently
comprises a mixture of a plurality of different organic directing
agents. Preferably, the mixture comprises at least one first organic
directing agent for directing the synthesis of a CHA framework-type
material and at least one second organic directing agent for directing
the synthesis of an AEI framework-type material.
[0057] Suitable first organic directing agents for directing the
synthesis of a CHA framework-type material include N,N,N-trimethyl-1-adamantammoniu-
m compounds, N,N,N-trimethyl-2-adamantammonium compounds, N,N,N-trimethylcyclohexylammonium
compounds, N,N-dimethyl-33-dimethylpip- eridinium compounds, N,N-methylethyl-33-dimethylpiperidinium
compounds, N,N-dimethyl-2-methylpiperidinium compounds, 13366-pentamethyl-6-azon-
io-bicyclo(3.2.1)octane compounds, N,N-dimethylcyclohexylamine,
and the bi- and tri-cyclic nitrogen containing organic compounds
cited in (1) Zeolites and Related Microporous Materials: State of
the Art 1994 Studies of Surface Science and Catalysis, Vol. 84
p 29-36; in (2) Novel Materials in Hetrogeneous Catalysis (ed. Terry
K. Baker & Larry L. Murrell), Chapter 2 p 14-24 May 1990
in (3) J. Am. Chem. Soc., 2000 122 p 263-273 and (4) in U.S. Pat.
Nos. 4544538 and 6709644. Suitable compounds include hydroxides
and salts, such as halides, especially chlorides and fluorides.
[0058] Suitable second organic directing agents for directing the
synthesis of an AEI framework-type material include N,N-diethyl-26-dimethylpiperdinium
compounds (mixture or either of the cis/trans isomers), N,N-dimethyl-26-dimethylpiperdinium
compounds (mixture or either of the cis/trans isomers), and the
directing agents cited in J. Am. Chem. Soc., 2000 122 p 263-273
and U.S. Pat. No. 5958370. Suitable compounds include hydroxides
and salts, such as halides, especially chlorides and fluorides.
[0059] Conveniently, the molar ratio of the first organic directing
agent to the second organic directing agent in the reaction mixture
is from about 0.01 to about 100 such as from about 0.02 to about
50 for example from about 0.03 to about 33 such as from about
0.03 to about 3 for example from about 0.05 to about 0.3.
[0060] In one embodiment, the organic directing agent comprises
a mixture of cyclic amines or ammonium compounds, particularly a
mixture where one component is a multi-cyclic amine or ammonium
compound and more particularly a mixture where one component is
a multi-cyclic amine or ammonium compound and another component
is a monocyclic amine or ammonium compound. Conveniently, the monocyclic
amine or ammonium compound comprises a substituted piperidine or
piperidinium compound, for example a tetraalkylpiperidinium compound,
typically an N,N-diethyl-26dimethylpi- peridinium compound. Conveniently,
the multi-cyclic amine or ammonium compound comprises a tetracyclic
amine or ammonium compound, such as an adamantylamine or ammonium
compound, for example an N,N,N-trialkyl-1-adamantylammonium compound;
typically an N,N,N-trimethyl-1-adamantylammonium compound. Thus
the term multi-cyclic amine is used herein to include multi-cyclic
compounds in which the N atom is external to the rings. Suitable
ammonium compounds include hydroxides and salts, such as halides,
especially chlorides.
[0061] Conveniently, the reaction mixture has a pH of about 4 to
about 14 such as about 4 to about 10 for example about 6 to about
8.
[0062] Crystallization can be carried out at either static or stirred
conditions in a suitable reactor vessel, such as for example, polypropylene
jars or Teflon.RTM.-lined or stainless steel autoclaves, at a temperature
of about 50.degree. C. to about 300.degree. C., such as about 135.degree.
C. to about 185.degree. C., for a time sufficient for crystallization
to occur. Formation of the crystalline product can take anywhere
from around 30 minutes up to as much as 2 weeks, such as from about
45 minutes to about 240 hours, for example from about 1.0 to about
120 hours. The duration depends on the temperature employed, with
higher temperatures typically requiring shorter hydrothermal treatments.
[0063] Synthesis of the new intergrowth 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
based on total weight of the reaction mixture. The seed crystals
can be homostructural with the crystalline material of the present
invention, for example the product of a previous synthesis, or can
be a heterostructural crystalline material, such as an AEI, LEV,
OFF, CHA or ERI framework-type molecular sieve. Conveniently, the
seed material is an AEI-type molecular sieve, and particularly an
AEI-type aluminosilicate. The seeds may be added to the reaction
mixture as a colloidal suspension in a liquid medium, such as water.
The production of colloidal seed suspensions and their use in the
synthesis of molecular sieves are disclosed in, for example, International
Publication Nos. WO 00/06493 and WO 00/06494 published on Feb. 10
2000 and incorporated herein by reference.
[0064] Typically, the crystalline product is formed in solution
and can be recovered by standard means, such as by centrifugation
or filtration. The separated product can also be washed, recovered
by centrifugation or filtration and dried.
[0065] 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. in the presence of
an oxygen-containing gas. In some cases, it may be desirable to
heat the molecular sieve in an environment having a low or zero
oxygen concentration. This type of process can be used for partial
or complete removal of the organic directing agent from the intracrystalline
pore system. In other cases, particularly with smaller organic directing
agents, complete or partial removal from the sieve can be accomplished
by conventional desorption processes.
[0066] Once the intergrown 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.
[0067] Materials which can be blended with the intergrown 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 intergrown 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.
[0068] The intergrown 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 chemical
carrier; in gas chromatography; and as a catalyst in organic conversion
reactions. Examples of suitable catalytic uses of the intergrown
crystalline material described herein include (a) hydrocracking
of heavy petroleum residual feedstocks, cyclic stocks and other
hydrocrackate charge stocks, normally in the presence of a hydrogenation
component selected from Groups 6 and 8 to 10 of the Periodic Table
of Elements; (b) dewaxing, including isomerization dewaxing, to
selectively remove straight chain paraffins from hydrocarbon feedstocks
typically boiling above 177.degree. C., including raffinates and
lubricating oil basestocks; (c) catalytic cracking of hydrocarbon
feedstocks, such as naphthas, gas oils and residual oils, normally
in the presence of a large pore cracking catalyst, such as zeolite
Y; (d) oligomerization of straight and branched chain olefins having
from about 2 to 21 preferably 2 to 5 carbon atoms, to produce medium
to heavy olefins which are useful for both fuels, i.e., gasoline
or a gasoline blending stock, and chemicals; (e) isomerization of
olefins, particularly olefins having 4 to 6 carbon atoms, and especially
normal butene to produce iso-olefins; (f) upgrading of lower alkanes,
such as methane, to higher hydrocarbons, such as ethylene and benzene;
(g) disproportionation of alkylaromatic hydrocarbons, such as toluene,
to produce dialkylaromatic hydrocarbons, such as xylenes; (h) alkylation
of aromatic hydrocarbons, such as benzene, with olefins, such as
ethylene and propylene to produce ethylbenzene and cumene; (i) isomerization
of dialkylaromatic hydrocarbons, such as xylenes, (j) catalytic
reduction of nitrogen oxides and (k) synthesis of monoalkylamines
and dialkylamines.
[0069] In particular, the intergrown crystalline material described
herein is useful as a catalyst in the conversion of oxygenates to
one or more olefins, particularly ethylene and propylene. As used
herein, the term "oxygenates" is defined to include, but
is not necessarily limited to aliphatic alcohols, ethers, carbonyl
compounds (aldehydes, ketones, carboxylic acids, carbonates, and
the like), and also compounds containing hetero-atoms, such as,
halides, mercaptans, sulfides, amines, and mixtures thereof. The
aliphatic moiety will normally contain from about 1 to about 10
carbon atoms, such as from about 1 to about 4 carbon atoms.
[0070] Representative oxygenates include lower straight chain or
branched aliphatic alcohols, their unsaturated counterparts, and
their nitrogen, halogen and sulfur analogues. Examples of suitable
oxygenate compounds include methanol; ethanol; n-propanol; isopropanol;
C.sub.4-C.sub.10 alcohols; methyl ethyl ether; dimethyl ether; diethyl
ether; di-isopropyl ether; methyl mercaptan; methyl sulfide; methyl
amine; ethyl mercaptan; di-ethyl sulfide; di-ethyl amine; ethyl
chloride; formaldehyde; di-methyl carbonate; di-methyl ketone; acetic
acid; n-alkyl amines, n-alkyl halides, n-alkyl sulfides having n-alkyl
groups of comprising the range of from about 3 to about 10 carbon
atoms; and mixtures thereof. Particularly suitable oxygenate compounds
are methanol, dimethyl ether, or mixtures thereof, most preferably
methanol. As used herein, the term "oxygenate" designates
only the organic material used as the feed. The total charge of
feed to the reaction zone may contain additional compounds, such
as diluents.
[0071] In the present oxygenate conversion process, a feedstock
comprising an organic oxygenate, optionally with one or more diluents,
is contacted in the vapor phase in a reaction zone with a catalyst
comprising the molecular sieve of the present invention at effective
process conditions so as to produce the desired olefins. Alternatively,
the process may be carried out in a liquid or a mixed vapor/liquid
phase. When the process is carried out in the liquid phase or a
mixed vapor/liquid phase, different conversion rates and selectivities
of feedstock-to-product may result depending upon the catalyst and
the reaction conditions.
[0072] When present, the diluent(s) is generally non-reactive to
the feedstock or molecular sieve catalyst composition and is typically
used to reduce the concentration of the oxygenate in the feedstock.
Non-limiting examples of suitable diluents include helium, argon,
nitrogen, carbon monoxide, carbon dioxide, water, essentially non-reactive
paraffins (especially alkanes such as methane, ethane, and propane),
essentially non-reactive aromatic compounds, and mixtures thereof.
The most preferred diluents are water and nitrogen, with water being
particularly preferred. Diluent(s) may comprise from about 1 mol
% to about 99 mol % of the total feed mixture.
[0073] The temperature employed in the oxygenate conversion process
may vary over a wide range, such as from about 200.degree. C. to
about 1000.degree. C., for example from about 250.degree. C. to
about 800.degree. C., including from about 250.degree. C. to about
750.degree. C., conveniently from about 300.degree. C. to about
650.degree. C., typically from about 350.degree. C. to about 600.degree.
C. and particularly from about 400.degree. C. to about 600.degree.
C.
[0074] Light olefin products will form, although not necessarily
in optimum amounts, at a wide range of pressures, including but
not limited to autogenous pressures and pressures in the range of
from about 0.1 kPa to about 10 MPa. Conveniently, the pressure is
in the range of from about 7 kPa to about 5 MPa, such as in the
range of from about 50 kPa to about 1 MPa. The foregoing pressures
are exclusive of diluent, if any is present, and refer to the partial
pressure of the feedstock as it relates to oxygenate compounds and/or
mixtures thereof. Lower and upper extremes of pressure may adversely
affect selectivity, conversion, coking rate, and/or reaction rate;
however, light olefins such as ethylene still may form.
[0075] The process should be continued for a period of time sufficient
to produce the desired olefin products. The reaction time may vary
from tenths of seconds to a number of hours. The reaction time is
largely determined by the reaction temperature, the pressure, the
catalyst selected, the weight hourly space velocity, the phase (liquid
or vapor) and the selected process design characteristics.
[0076] A wide range of weight hourly space velocities (WHSV) for
the feedstock will function in the present process. WHSV is defined
as weight of feed (excluding diluent) per hour per weight of a total
reaction volume of molecular sieve catalyst (excluding inerts and/or
fillers). The WHSV generally should be in the range of from about
0.01 hr.sup.-1 to about 500 hr.sup.-1 such as in the range of from
about 0.5 hr.sup.-1 to about 300 hr.sup.-1 for example in the range
of from about 0.1 hr.sup.-1 to about 200 hr.sup.-1.
[0077] A practical embodiment of a reactor system for the oxygenate
conversion process is a circulating fluid bed reactor with continuous
regeneration, similar to a modern fluid catalytic cracker. Fixed
beds are generally not preferred for the process because oxygenate
to olefin conversion is a highly exothermic process which requires
several stages with intercoolers or other cooling devices. The reaction
also results in a high pressure drop due to the production of low
pressure, low density gas.
[0078] Because the catalyst must be regenerated frequently, the
reactor should allow easy removal of a portion of the catalyst to
a regenerator, where the catalyst is subjected to a regeneration
medium, such as a gas comprising oxygen, for example air, to burn
off coke from the catalyst, which restores the catalyst activity.
The conditions of temperature, oxygen partial pressure, and residence
time in the regenerator should be selected to achieve a coke content
on regenerated catalyst of less than about 0.5 wt %. At least a
portion of the regenerated catalyst should be returned to the reactor.
[0079] In one embodiment, prior to being used to convert oxygenate
to olefins, the catalyst is pretreated with dimethyl ether, a C.sub.2-C.sub.4
aldehyde composition and/or a C.sub.4-C.sub.7 olefin composition
to form an integrated hydrocarbon co-catalyst within the porous
framework of the intergrown molecular sieve. Desirably, the pretreatment
is conducted at a temperature of at least 10.degree. C., such as
at least 25.degree. C., for example at least 50.degree. C., higher
than the temperature used for the oxygenate reaction zone and is
arranged to produce at least 0.1 wt %, such as at least 1 wt %,
for example at least about 5 wt % of the integrated hydrocarbon
co-catalyst, based on total weight of the molecular sieve. Such
preliminary treating to increase the carbon content of the molecular
sieve is known as "pre-pooling" and is further described
in U.S. application Ser. Nos. 10/712668 10/712952 and 10/712953
all of which were filed Nov. 12 2003 and are incorporated herein
by reference.
[0080] The invention will now be more particularly described with
reference to the following Examples and the accompanying drawings.
In the Examples, the X-ray diffraction data were collected with
several types of instruments:
[0081] Philips XRD shall hereinafter refer to X-ray diffraction
data collected with a Philips powder X-Ray Diffractometer, equipped
with a scintillation detector with graphite monochromator, 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 1 second for each step. The interplanar
spacings, d's, were calculated in Angstrom units, and the relative
intensities of the lines, I/I.sub.o, where I.sub.o is the intensity
of the strongest line, above background were determined by integrating
the peak intensities.
[0082] Synchrotron XRD shall hereinafter refer to powder X-ray
diffraction data collected at Brookhaven National Labs on beamline
X10B with a monochromatic radiation wavelength of 0.8695 .ANG. using
Debye-Scherrer geometry. Samples were first calcined in air at 600.degree.
C. for 3 hours to remove the template. The calcined samples were
then sealed in 2 mm outside diameter quartz capillary tubes while
out-gassing at 300.degree. C. under vacuum (<0.1 torr). The diffraction
data were recorded by step-scanning at 0.01 degrees two-theta, where
theta is the Bragg angle. The counting time was automatically adjusted
for each step during the measurement so that a separate beam monitor
detector registered 30000 counts (typically 5.2-5.4 seconds). The
interplanar spacings, d's, were calculated in Angstrom units, and
the relative intensities of the lines, I/Io, where Io is the intensity
of the strongest line, above background were determined by integrating
the peak intensities.
[0083] Scintag XRD shall hereinafter refer to X-ray diffraction
data collected with a Scintag X2 X-Ray Diffractometer equipped with
a Peltier-cooled solid state detector, using copper K-alpha radiation.
The diffraction data were recorded by step-scanning at 0.02 degrees
two-theta, where theta is the Bragg angle, and a counting time of
0.3 second for each step. The interplanar spacing, d's, were calculated
in Angstrom units, and the relative intensities of the lines, I/Io,
where Io is the intensity of the strongest line, above background
were determined by integrating the peak intensities.
[0084] X-ray diffraction data for the calcined samples was obtained
by subjecting the as-synthesized product to the following calcination
procedure. About 2 grams of the as-synthesized product were heated
from room temperature to 200.degree. C. under a flow of nitrogen
at a rate of 2.degree. C. per minute. The temperature was held at
200.degree. C. for 30 minutes and then the sample was heated from
200.degree. C. to 650.degree. C. under nitrogen again at a rate
of 2.degree. C. per minute. The sample was held at 650.degree. C.
under nitrogen for 5-8 hours, whereafter the nitrogen was then replaced
by air and the sample was kept at 650.degree. C. under air for 3
hours. The sample was then cooled to 200.degree. C. and kept at
200.degree. C. to prevent hydration. The hot sample was then transferred
into the XRD sample cup and was covered by Mylar foil to prevent
hydration.
[0085] DIFFaX analysis was used to determine the AEI/CHA ratio
of the molecular sieves. For DIFFaX analysis, powder XRD diffraction
patterns for varying ratios of AEI/CHA were generated using the
DIFFaX program available from the International Zeolite Association
(see also M. M. J. Treacy et al., Proceedings of the Royal Chemical
Society, London, A (1991), Vol. 433 pp. 499-520 "Collection
of Simulated XRD Powder Patterns for Zeolites" by M. M. J.
Treacy and J. B. Higgins, 2001 Fourth Edition, published on behalf
of the Structure Commission of the International Zeolite Association).
Table 1 gives the DIFFaX input file used to simulate the XRD diffraction
pattern of a 50/50 intergrowth. For the purposes of this analysis,
calculations were based on a random distribution of the layers.
Such calculations are used for statistical purposes only, and do
not mean that the true nature of the material is necessarily random.
2TABLE 1 {Data File for Random AEI-CHA Intergrowths - Starting
from an All Si AEI Unit Cell} {This file is for a 50% probability
of a transition generating CHA-type cages and a 50% probability
of a transition generating AEI-type cages} INSTRUMENTAL {Header
for instrumental section} X-RAY {Simulate X-ray diffraction} 1.54056
{X-ray wavelength} PSEUDO-VOIGT 0.1 -0.036 0.009 0.6 {Instrumental
broadening (much slower)} STRUCTURAL {Header for structural section}
13.5155 12.5460 18.3306 90. {unit cell coordinates a, b, c, and
gamma} UNKNOWN {P1 - all coordinates given} 2 {Layer 1 & Layer
2} infinite {Layers are very wide in the a-b plane} LAYER 1 NONE
Si4+ 3 0.88217 0.04597 -0.16618 1.50 1.0 Si4+ 5 0.11783 0.04597
-0.16618 1.50 1.0 Si4+ 11 0.38217 0.54597 -0.16618 1.50 1.0 Si4+
13 0.61783 0.54597 -0.16618 1.50 1.0 O 2- 91 0.00000 0.02575 -0.16208
3.00 1.0 O 2- 95 0.50000 0.52575 -0.16208 3.00 1.0 O 2- 59 0.67484
0.44369 -0.13307 3.00 1.0 O 2- 61 0.32516 0.44369 -0.13307 3.00
1.0 O 2- 51 0.17484 0.94369 -0.13307 3.00 1.0 O 2- 53 0.82516 0.94369
-0.13307 3.00 1.0 O 2- 99 0.14671 0.15098 -0.11991 3.00 1.0 O 2-
101 0.85329 0.15098 -0.11991 3.00 1.0 O 2- 107 0.64671 0.65098 -0.11991
3.00 1.0 O 2- 109 0.35329 0.65098 -0.11991 3.00 1.0 O 2- 123 0.81919
0.34223 -0.06605 3.00 1.0 O 2- 125 0.18081 0.34223 -0.06605 3.00
1.0 O 2- 115 0.31919 0.84223 -0.06605 3.00 1.0 O 2- 117 0.68081
0.84223 -0.06605 3.00 1.0 O 2- 81 0.00000 0.26532 -0.06597 3.00
1.0 O 2- 85 0.50000 0.76532 -0.06597 3.00 1.0 Si4+ 17 0.88446 0.23517
-0.05737 1.50 1.0 Si4+ 23 0.11554 0.23517 -0.05737 1.50 1.0 Si4+
25 0.38446 0.73517 -0.05737 1.50 1.0 Si4+ 31 0.61554 0.73517 -0.05737
1.50 1.0 Si4+ 43 0.71381 0.40077 -0.05514 1.50 1.0 Si4+ 45 0.28619
0.40077 -0.05514 1.50 1.0 Si4+ 35 0.21381 0.90077 -0.05514 1.50
1.0 Si4+ 37 0.78619 0.90077 -0.05514 1.50 1.0 O 2- 75 0.63494 0.31721
-0.02183 3.00 1.0 O 2- 77 0.36506 0.31721 -0.02183 3.00 1.0 O 2-
67 0.13494 0.81721 -0.02183 3.00 1.0 O 2- 69 0.86506 0.81721 -0.02183
3.00 1.0 O 2- 137 0.22748 0.00000 0.00000 3.00 1.0 O 2- 139 0.77252
0.00000 0.00000 3.00 1.0 O 2- 141 0.72748 0.50000 0.00000 3.00 1.0
O 2- 143 0.27252 0.50000 0.00000 3.00 1.0 O 2- 65 0.13494 0.18279
0.02183 3.00 1.0 O 2- 71 0.86506 0.18279 0.02183 3.00 1.0 O 2- 73
0.63494 0.68279 0.02183 3.00 1.0 O 2- 79 0.36506 0.68279 0.02183
3.00 1.0 Si4+ 33 0.21381 0.09923 0.05514 1.50 1.0 Si4+ 39 0.78619
0.09923 0.05514 1.50 1.0 Si4+ 41 0.71381 0.59923 0.05514 1.50 1.0
Si4+ 47 0.28619 0.59923 0.05514 1.50 1.0 Si4+ 27 0.38446 0.26483
0.05737 1.50 1.0 Si4+ 29 0.61554 0.26483 0.05737 1.50 1.0 Si4+ 19
0.88446 0.76483 0.05737 1.50 1.0 Si4+ 21 0.11554 0.76483 0.05737
1.50 1.0 O 2- 87 0.50000 0.23468 0.06597 3.00 1.0 O 2- 83 0.00000
0.73468 0.06597 3.00 1.0 O 2- 113 0.31919 0.15777 0.06605 3.00 1.0
O 2- 119 0.68081 0.15777 0.06605 3.00 1.0 O 2- 121 0.81919 0.65777
0.06605 3.00 1.0 O 2- 127 0.18081 0.65777 0.06605 3.00 1.0 O 2-
105 0.64671 0.34902 0.11991 3.00 1.0 O 2- 111 0.35329 0.34902 0.11991
3.00 1.0 O 2- 97 0.14671 0.84902 0.11991 3.00 1.0 O 2- 103 0.85329
0.84902 0.11991 3.00 1.0 O 2- 49 0.17484 0.05631 0.13307 3.00 1.0
O 2- 55 0.82516 0.05631 0.13307 3.00 1.0 O 2- 57 0.67484 0.55631
0.13307 3.00 1.0 O 2- 63 0.32516 0.55631 0.13307 3.00 1.0 O 2- 93
0.50000 0.47425 0.16208 3.00 1.0 O 2- 89 0.00000 0.97425 0.16208
3.00 1.0 Si4+ 9 0.38217 0.45403 0.16618 1.50 1.0 Si4+ 15 0.61783
0.45403 0.16618 1.50 1.0 Si4+ 1 0.88217 0.95403 0.16618 1.50 1.0
Si4+ 7 0.11783 0.95403 0.16618 1.50 1.0 O 2- 133 0.34894 0.43713
0.25000 3.00 1.0 O 2- 136 0.65106 0.43713 0.25000 3.00 1.0 O 2-
129 0.84894 0.93713 0.25000 3.00 1.0 O 2- 132 0.15106 0.93713 0.25000
3.00 1.0 LAYER 2 NONE Si4+ 12 0.61783 0.45403 -0.16618 1.50 1.0
Si4+ 14 0.38217 0.45403 -0.16618 1.50 1.0 Si4+ 4 0.11783 0.95403
-0.16618 1.50 1.0 Si4+ 6 0.88217 0.95403 -0.16618 1.50 1.0 O 2-
96 0.50000 0.47425 -0.16208 3.00 1.0 O 2- 92 0.00000 0.97425 -0.16208
3.00 1.0 O 2- 52 0.82516 0.05631 -0.13307 3.00 1.0 O 2- 54 0.17484
0.05631 -0.13307 3.00 1.0 O 2- 60 0.32516 0.55631 -0.13307 3.00
1.0 O 2- 62 0.67484 0.55631 -0.13307 3.00 1.0 O 2- 108 0.35329 0.34902
-0.11991 3.00 1.0 O 2- 110 0.64671 0.34902 -0.11991 3.00 1.0 O 2-
100 0.85329 0.84902 -0.11991 3.00 1.0 O 2- 102 0.14671 0.84902 -0.11991
3.00 1.0 O 2- 116 0.68081 0.15777 -0.06605 3.00 1.0 O 2- 118 0.31919
0.15777 -0.06605 3.00 1.0 O 2- 124 0.18081 0.65777 -0.06605 3.00
1.0 O 2- 126 0.81919 0.65777 -0.06605 3.00 1.0 O 2- 86 0.50000 0.23468
-0.06597 3.00 1.0 O 2- 82 0.00000 0.73468 -0.06597 3.00 1.0 Si4+
26 0.61554 0.26483 -0.05737 1.50 1.0 Si4+ 32 0.38446 0.26483 -0.05737
1.50 1.0 Si4+ 18 0.11554 0.76483 -0.05737 1.50 1.0 Si4+ 24 0.88446
0.76483 -0.05737 1.50 1.0 Si4+ 36 0.78619 0.09923 -0.05514 1.50
1.0 Si4+ 38 0.21381 0.09923 -0.05514 1.50 1.0 Si4+ 44 0.28619 0.59923
-0.05514 1.50 1.0 Si4+ 46 0.71381 0.59923 -0.05514 1.50 1.0 O 2-
68 0.86506 0.18279 -0.02183 3.00 1.0 O 2- 70 0.13494 0.18279 -0.02183
3.00 1.0 O 2- 76 0.36506 0.68279 -0.02183 3.00 1.0 O 2- 78 0.63494
0.68279 -0.02183 3.00 1.0 O 2- 138 0.77252 0.00000 0.00000 3.00
1.0 O 2- 140 0.22748 0.00000 0.00000 3.00 1.0 O 2- 142 0.27252 0.50000
0.00000 3.00 1.0 O 2- 144 0.72748 0.50000 0.00000 3.00 1.0 O 2-
74 0.36506 0.31721 0.02183 3.00 1.0 O 2- 80 0.63494 0.31721 0.02183
3.00 1.0 O 2- 66 0.86506 0.81721 0.02183 3.00 1.0 O 2- 72 0.13494
0.81721 0.02183 3.00 1.0 Si4+ 42 0.28619 0.40077 0.05514 1.50 1.0
Si4+ 48 0.71381 0.40077 0.05514 1.50 1.0 Si4+ 34 0.78619 0.90077
0.05514 1.50 1.0 Si4+ 40 0.21381 0.90077 0.05514 1.50 1.0 Si4+ 20
0.11554 0.23517 0.05737 1.50 1.0 Si4+ 22 0.88446 0.23517 0.05737
1.50 1.0 Si4+ 28 0.61554 0.73517 0.05737 1.50 1.0 Si4+ 30 0.38446
0.73517 0.05737 1.50 1.0 O 2- 84 0.00000 0.26532 0.06597 3.00 1.0
O 2- 88 0.50000 0.76532 0.06597 3.00 1.0 O 2- 122 0.18081 0.34223
0.06605 3.00 1.0 O 2- 128 0.81919 0.34223 0.06605 3.00 1.0 O 2-
114 0.68081 0.84223 0.06605 3.00 1.0 O 2- 120 0.31919 0.84223 0.06605
3.00 1.0 O 2- 98 0.85329 0.15098 0.11991 3.00 1.0 O 2- 104 0.14671
0.15098 0.11991 3.00 1.0 O 2- 106 0.35329 0.65098 0.11991 3.00 1.0
O 2- 112 0.64671 0.65098 0.11991 3.00 1.0 O 2- 58 0.32516 0.44369
0.13307 3.00 1.0 O 2- 64 0.67484 0.44369 0.13307 3.00 1.0 O 2- 50
0.82516 0.94369 0.13307 3.00 1.0 O 2- 56 0.17484 0.94369 0.13307
3.00 1.0 O 2- 90 0.00000 0.02575 0.16208 3.00 1.0 O 2- 94 0.50000
0.52575 0.16208 3.00 1.0 Si4+ 2 0.11783 0.04597 0.16618 1.50 1.0
Si4+ 8 0.88217 0.04597 0.16618 1.50 1.0 Si4+ 10 0.61783 0.54597
0.16618 1.50 1.0 Si4+ 16 0.38217 0.54597 0.16618 1.50 1.0 O 2- 130
0.15106 0.06287 0.25000 3.00 1.0 O 2- 131 0.84894 0.06287 0.25000
3.00 1.0 O 2- 134 0.65106 0.56287 0.25000 3.00 1.0 O 2- 135 0.34894
0.56287 0.25000 3.00 1.0 STACKING {Header for stacking description}
recursive {Statistical ensemble} infinite {Infinite number of layers}
TRANSITIONS {Header for stacking transition data} {Transitions from
layer 1} 0.50 0.0 -0.0810 0.5 {layer 1 to layer 1: CHA-type cages}
0.50 0.0 0.0 0.5
{layer 1 to layer 2: AEI-type cages} {Transitions from layer 2}
0.50 0.0 0.0 0.5 {layer 2 to layer 1: AEI-type cages} 0.50 0.0 0.0810
0.5 {layer 2 to layer 2: CHA-type cages}
[0086] FIGS. 1a and 1b show the simulated diffraction patterns
calculated by DIFFaX for single intergrown zeolite phases having
various AEI/CHA ratios, normalized to the highest peak of the entire
set, i.e. the peak at about 9.6 2.theta. for the 100% CHA case which
was set to 100. The diffractograms were simulated using the following
parameter settings: all Si AEI_CHA .lambda.=1.54056 PSEUDO-VOIGT
0.1-0.036; line broadening: 0.009: 0.6. A non-linear least-squares
procedure ("DIFFaX Analysis") was then used to refine
the contribution of one or more phases, and of the background and
the 2.theta. shift required to fit the experimental profile. An
intergrowth sensitive region (see e.g. FIG. 3) was always chosen
in order to maximize the sensitivity of the calculations. Alternatively,
a manual trial-and-error fit can be performed for identifying the
type and magnitude of the contributing phases, the background counts
and the 20 shift. For materials characterized by the presence of
more than one intergrown phase, the contribution of AEI and CHA
was calculated by a least squares analysis method, summing the AEI
and CHA contribution of each intergrown phases. For Synchrotron
XRDs, the comparison with the DIFFaX simulated patterns was done
by converting the experimental XRD patterns to CuK.alpha.1 (.lambda.=1.54056
A).
[0087] In addition, the .sup.13C MAS (magic-angle spinning) NMR
spectra were obtained using a Chemagnetics.RTM. CMXII-200 spectrometer
operating at a static field of 4.7 T (199.9 MHz .sup.1H, 50.3 MHz
.sup.13C). The as-synthesized samples were loaded in MAS ZrO.sub.2
NMR rotors (5-mm o.d.) and spun at the magic angle. The .sup.13C
MAS NMR (or Bloch decay) experiments were performed using a doubly-tuned
probe by applying a (90.degree.) .sup.13C pulse followed by .sup.13C
data acquisition. A .sup.1H-.sup.13C dipolar-decoupling field of
about 62-kHz was used during .sup.13C data acquisition. The .sup.13C
Bloch decay spectra were obtained at 8-kHz MAS using a pulse delay
of about 60-sec. The free-induction decays thus obtained were Fourier
transformed (with a 25 Hz exponential line broadening filter). The
.sup.13C chemical shifts are referenced with respect to an external
solution of tetramethyl silane (TMS .delta..sub.C=0.0 ppm), using
hexamethyl benzene as a secondary standard. One or more of the none-overlapping
regions can be taken and its relative intensity determined. This
can in turn be converted into mole ratio of the specific template
whereby the relative contribution of one template versus the other
can be calculated. All solid-state NMR measurements were done at
room temperature.
[0088] TEM analysis included both Bright-Field TEM imaging (BF-TEM)
and High-Resolution TEM imaging (HR-TEM).
[0089] TEM data were obtained by crushing individual as-calcined
samples into fines (<100 nm thick) using an agate mortar and
pestle. The fines were transferred into a flat bed mold, embedded
in a standard mix of LR White hard grade resin (Polysciences, Inc.,
USA), and cured under ambient conditions. The resin blocks were
removed from the flat bed molds and placed "end on" into
polyethylene BEEM capsules. Each BEEM capsule was filled with a
standard mix of LR White hard grade embedding resin and cured under
ambient conditions. The cured resin blocks were removed from the
BEEM capsules and placed into a Reichert-Jung Ultracut E microtome.
Electron transparent sections (.about.100 nm thick) were ultramicrotomed
at ambient temperature from the resin blocks using a diamond knife.
The microtomy process fractured the samples into many small sections,
which were floated off on water and collected onto standard, 200
mesh carbon-coated TEM grids. After air-drying, the grids were examined
in the bright field TEM imaging mode of a Philips CM200F TEM/STEM
at an accelerating voltage of 200 kV. Each small section of material
was identified as a chard in the TEM analysis. In order to quantify
the number of faulted crystals, 500 chards of each sample were examined
at low magnification, and the presence of stacking faults or twins
was noted by visual inspection. The number of faulted crystals is
expressed as the number of chards that show one or more faults or
twins in a total of 500 chards.
[0090] HR-TEM data were obtained by embedding the calcined samplez
in LR White hard grade resin (The London Resin Co., UK). Then, without
adding the curing accelerator; the resin was thermally cured at
80.degree. C. for at least 3 hours in a nitrogen atmosphere. Electron
transparent thin sections were cut at ambient temperature using
a Boeckeler Powertome XL ultra-microtome equipped with a diamond
knife. The thin sections were collected on lacey carbon TEM grids.
HR-TEM analysis was done in a Philips CM12T transmission electron
microscope at an accelerating voltage of 120 kV. The crystals were
carefully oriented with the appropriate zone axis parallel to the
electron beam and high-resolution TEM images were recorded on photographic
plate at a nominal magnification of 100000.times..
EXAMPLE 1
[0091] 0.286 ml of a 23.5 mg/ml aqueous solution of Al(NO.sub.3).sub.3.9H.sub.2O
was added to a mixture of 8.060 ml of an aqueous solution of N,N-diethyl-26-dimethylpiperidinium
hydroxide, DEDMP.sup.+ OH.sup.-, (0.6008 molar) and 1.000 ml of
an aqueous solution of N,N,N-tri-methyl-1-adamantylammonium hydroxide,
TMAA.sup.+ OH.sup.-, (0.5379 molar). 2.400 ml of tetraethylorthosilicate
was then added to this composition and the resultant mixture was
continuously stirred in a sealed container for at least 2-3 hours
at room temperature until all the tetraethylorthosilicate was completely
hydrolyzed. To the resultant clear solution was added 0.234 ml of
a 48 wt % aqueous solution of hydrofluoric acid which immediately
resulted in the production of a slurry. This slurry was further
homogenized by stirring and exposure to air for evaporation of water
and ethanol until a thick slurry mixture was obtained. Extra water
was further evaporated from the slurry mixture under static conditions
to give 2672 mg of a dry gel solid having the following molar composition:
SiO.sub.2:0.00083Al.sub.2O.sub.3:0.45DEDMP:0.05TMAA:0.6F:5.0H.sub.2O
[0092] To this solid was added with mechanical mixing 10 mg (0.37
wt % based on the dry gel solid) of a seeding material, AEI having
a Si/Al atomic ratio of 8.9 and Si/Na atomic ratio of 26.4. The
resulting mixture of solids was transferred to a Teflon.RTM.-lined
5 ml pressure reactor and crystallized at 150.degree. C. for 65
hours under slow rotation (about 60 rpm). After cooling, the resultant
solid was recovered by centrifuging, washed with distilled water,
and dried at 100.degree. C. to give 775 mg of a white microcrystalline
solid (29.0% yield based on the weight of the dry gel). The as-synthesized
product had the X-ray diffraction pattern summarized in Table 2
below. The calcined product had the Scintag X-ray diffraction pattern
shown in FIG. 2.
[0093] DIFFaX analysis was conducted on the X-ray pattern of FIG.
2 and the results are summarized in FIG. 3. FIG. 3 shows that the
product of Example 1 is characterized by the presence of more than
one random intergrown AEI/CHA phase. Least squares analysis shows
that the product of Example 1 is composed of about 56 wt % of a
first intergrown AEI/CHA phase having an AEI/CHA ratio of 15/85
and about 44 wt % of a second intergrown AEI/CHA phase having an
AEI/CHA ratio of 75/25 such that the weighted average AEI/CHA ratio
of the material was about 41/59.
[0094] SEM analysis of the calcined product showed particles having
a thick plate morphology and a size of about 1-2 micron. Chemical
analysis showed the silica/alumina molar ratio of the product to
be 1200.
3TABLE 2 X-Ray Diffraction Pattern of As-Synthesized Product of
Example 1 2 Theta d(.ANG.) 100 I/Io 9.75 9.069 100.0 13.20 6.703
6.1 14.28 6.197 15.0 16.38 5.406 96.5 17.27 5.129 8.4 18.11 4.896
10.6 19.40 4.572 3.4 21.04 4.220 89.0 21.63 4.106 6.4 22.44 3.959
7.9 22.86 3.887 3.7 23.54 3.776 3.0 24.36 3.651 5.0 25.39 3.505
17.6 26.44 3.369 20.6 28.21 3.160 5.1 30.12 2.965 6.1 31.25 2.860
28.5 31.63 2.827 18.8 32.95 2.716 4.2 35.20 2.547 2.8 36.63 2.451
3.6 40.46 2.228 2.0 43.66 2.071 3.0 44.22 2.047 3.2
EXAMPLE 2
[0095] The synthesis of Example 1 was repeated in two separate
experiments using the same starting materials in the same proportions
as Example 1 but with the crystallization temperatures being 135.degree.
C. and 175.degree. C. respectively. DIFFaX analysis was conducted
as described in example 1 on the Synchrotron X-ray diffraction pattern
of the calcined product of the 175.degree. C. synthesis and showed
the presence of two intergrown AEI/CHA phases, namely about 78 wt
% of a first intergrown phase having an AEI/CHA ratio of 5/95 and
and about 22 wt % of a second intergrown phase having an AEI/CHA
ratio of 95/5 which corresponds to a weighted average AEI/CHA ratio
of about 25/75.
[0096] .sup.13C MAS NMR analysis of the product of the 175.degree.
C. synthesis showed the presence of DEDMP (the AEI directing agent)
and TMAA (the CHA directing agent) in a molar ratio of 50/50 in
the as-synthesized product. This contrasts with a DEDMP:TMAA molar
ratio of 90/10 in the synthesis mixture.
[0097] A high resolution transmission electron micrograph of the
product of the 175.degree. C. synthesis is shown in FIG. 4 and confirms
the presence of twinned/faulted CHA crystals with intercalated regions
of faulted AEI phase material.
EXAMPLE 3
[0098] The synthesis of Example 1 was repeated with the molar ratio
of DEDMP/TMAA in the synthesis mixture being 1.0. DIFFaX analysis
on the Synchrotron X-ray diffraction pattern of the as-calcined
product showed the product to be pure CHA. In addition, .sup.13C
MAS NMR analysis showed the presence of only TMAA (the CHAdirecting
agent) in the as-synthesized product. A HR-TEM transmission electron
micrograph of the product is shown in FIG. 5. No presence of faulting
is apparent in the HR-TEM image. The Fourier Transform of the HR-TEM
image shows sharp spots and no streaks, which is indicative of a
regular stacking and of the absence of stacking faults or twins.
No faults were observed in the 500 chards produced for the TEM analysis.
EXAMPLE 4
[0099] The synthesis of Example 1 was repeated with the molar ratio
of DEDMP/TMAA in the synthesis mixture being 5.67 and the crystallization
temperature being 175.degree. C. DIFFaX analysis on the Synchrotron
X-ray diffraction pattern of the as-calcined product showed the
presence of three phases, namely about 73.5 wt % of a first intergrown
phase having an AEI/CHA ratio of 5/95 about 5.2 wt % of a second
intergrown phase having an AEI/CHA ratio of 90/10 and about 21.3
wt % of a third phase having an AEI/CHA ratio of 0/100 which corresponds
to a weighted average AEI/CHA ratio of about 8.5/91.5. .sup.13C
MAS NMR analysis showed the presence of DEDMP (the AEI directing
agent) and TMAA (the CHA directing agent) in a molar ratio of 23/77
in the as-synthesized product.
EXAMPLE 5 (COMPARATIVE)
[0100] The process described in U.S. Pat. No. 4544538 was repeated
to produce SSZ-13 as follows. 2.00 g 1N NaOH, 2.78 g 0.72 molar
N,N,N-trimethyladamantammonium hydroxide, and 3.22 g deionized water
were added sequentially to a 23 ml Teflon lined Parr autoclave.
To the resultant solution 0.05 g of aluminum hydroxide (Teheis F-2000
dried gel, 50% Al.sub.2O.sub.3) was added and the solution was mixed
until it cleared. 0.60 g fumed silica (Cab-O-Sil, M5 grade, 97%
SiO.sub.2) was then added to the autoclave and the solution was
mixed until uniform.
[0101] The autoclave was sealed and heated without agitation at
160.degree. C. for 4 days. The autoclave was then cooled to room
temperature and the solid product recovered by filtration. The product
was washed repeatedly with deionized water and then dried in a vacuum
oven at 50.degree. C.
[0102] X-ray diffraction analysis showed the product to be pure
CHA framework type molecular sieve. A transmission electron micrograph
of the product is shown in FIG. 6. No presence of faulting is apparent
in the TEM and no faults were observed in the 500 chards produced
for the TEM analysis.
EXAMPLE 6 (COMPARATIVE)
[0103] A sample of a light brown colored natural chabazite was
obtained from western US. It was analyzed to have Si/Al=3.70 0.28
wt % Na, 0.33 wt % K, 0.03 wt % Ca, 0.28 wt % Mg, and 1.50 wt %
Fe. The sample was subjected to transmission electron microscopy
without any prior treatment and the results are shown in FIG. 7.
No presence of faulting was apparent in the BF-TEM and no faults
were observed in the 500 chards produced for the BF-TEM analysis.
EXAMPLE 7
[0104] 0.239 ml of a 23.5 mg/ml aqueous solution of Al(NO.sub.3).sub.3.9H.sub.2O
was added to a mixture of 5.597 ml of an aqueous solution of N,N-diethyl-26-dimethylpiperidinium
hydroxide, DEDMP.sup.+ OH.sup.-, (0.6008 molar) and 1.959 ml of
an aqueous solution of N,N,N-tri-methyl-1-adamantylammonium hydroxide,
TMAA.sup.+ OH.sup.-, (0.5721 molar). 2.000 ml of tetraethylorthosilicate
was then added to this composition and the resultant mixture was
continuously stirred in a sealed container for 15 hours at room
temperature until all the tetraethylorthosilicate was completely
hydrolyzed. To the resultant clear solution was added 0.195 ml of
a 48 wt % aqueous solution of hydrofluoric acid which immediately
resulted in the production of a slurry., This slurry was further
homogenized by stirring and exposure to air for evaporation of water
and ethanol until a thick slurry mixture was obtained. To this thick
slurry, 0.058 ml (0.37 wt. % based on the weight of the dry gel)
of LEV colloidal seeds (SiO.sub.2/Al.sub.2O.sub.3=12) suspension
slurry (14.1 wt. %) containing 4478 wt. ppm of sodium and 18000
wt. ppm of potassium was added and stirring was continued for another
10 minutes. Extra water was further evaporated from the slurry mixture
under static conditions to give 2242 mg of a dry gel solid having
the following molar composition:
SiO.sub.2:0.00083Al.sub.2O.sub.3:0.375DEDMP:0.125TMAA:0.6F:5.0H.sub.2O
[0105] The resulting mixture of solids was transferred to a Teflon.RTM.-lined
5 ml reactor and crystallized at 175.degree. C. for 65 hours under
slow rotation (about 60 rpm). After cooling, the resultant solid
was recovered by centrifuging, washed with distilled water, and
dried at 100.degree. C. to give 634 mg of a white microcrystalline
solid (28.3% yield based on the weight of the dry gel). The Synchrotron
X-ray diffraction pattern of as-synthesized product is shown in
Table 3 whereas the X-ray diffraction pattern of the as-calcined
product is shown in FIG. 8.
[0106] DIFFaX analysis on the calcined Synchrotron X-ray pattern
of FIG. 8 suggests the material of Example 7 is a pure CHA phase
material. However, .sup.13C MAS NMR analysis showed the presence
of DEDMP (the AEI directing agent) and TMAA (the CHA directing agent)
in a molar ratio of 13/87 in the as-synthesized product. The HR-TEM
of the product is shown in FIG. 9 and clearly shows the crystal
is faulted. To quantify the amount of faulting, 500 chards were
analyzed in BF-TEM and 10% of the chards showed faults.
[0107] .sup.13C MAS NMR analysis showed the presence of DEDMP (the
AEI directing agent) and TMAA (the CHA directing agent) in a molar
ratio of 13/87 in the as-synthesized product. SEM analysis of the
calcined product showed particles having a thick plate morphology
and a size of about 0.5 micron. Chemical analysis showed the silica/alumina
molar ratio of the product to be 1200.
4TABLE 3 X-Ray Diffraction Pattern of As- Synthesized Product of
Example 7 2 Theta d(.ANG.) 100 I/Io 9.50 9.300 30.8 12.96 6.825
2.7 14.03 6.308 14.7 16.15 5.484 64.9 17.85 4.965 14.8 19.20 4.620
1.9 20.82 4.263 100.0 22.18 4.005 10.3 22.66 3.922 8.6 23.30 3.815
3.2 25.12 3.542 33.3 26.24 3.393 24.0 28.01 3.183 4.5 28.42 3.138
3.2 29.93 2.983 4.0 31.03 2.880 50.1 31.40 2.847 17.8 31.97 2.797
1.3 32.78 2.730 2.8 33.81 2.649 2.2 35.00 2.561 4.6 35.44 2.531
1.7 36.41 2.465 5.5 38.82 2.318 1.0 39.12 2.301 1.6 40.29 2.237
4.5 42.53 2.124 0.8 43.31 2.087 4.2 44.08 2.053 6.6 45.75 1.981
0.4 47.55 1.911 1.6 48.45 1.877 4.5 49.55 1.838 5.9
EXAMPLE 8
[0108] The as-synthesized materials from Examples 1 and 2 were
individually pressed to pellets at 30000 psig (2.07.times.10.sup.5
kPa) and then ground and sieved to between 80 and 125 .mu.m. Two
separate samples of each of the sized materials were weighed between
21 and 22 mg and mixed separately with 90 mg of 100 .mu.m silicon
carbide. These mixtures were loaded into separate 1.9 mm internal
diameter tubes sealed at the bottom with a quartz frit. The tubes
were sealed into heated reactor blocks and the catalysts were then
calcined at 540.degree. C. under flowing air for 2 hours to effect
organic template removal. The calcined catalysts were then subjected
to a mixture of 85% methanol in N.sub.2 at 500.degree. C., approximately
100 weight hourly space velocity (WHSV), and 40 psia (276 kPa) methanol
partial pressure for 25 minutes. During the methanol reactions the
reactor effluents were collected and stored at timed intervals for
analysis by gas chromatography. Following the methanol reaction
the catalysts were subjected to a flow of 50% oxygen in nitrogen
at 550.degree. C. for approximately 90 minutes to burn off deposited
coke. The reactor effluents were analyzed by infrared spectroscopy
with quantitation of both carbon monoxide and carbon dioxide to
determine the amounts of coke deposition.
[0109] Selectivities to hydrocarbon products were calculated. The
values given below are averages of each individual selectivity over
the entire reaction. Each value represents an average of the selectivities
obtained from the two individual repeats.
5 Crystallization Temperature (.degree. C.) Selectivity 135 150
175 C.sub.1 1.4 1.1 1.0 C.sub.2.sup.0 0.1 0.1 0.1 C.sub.2.sup.=
28.2 27.9 28.7 C.sub.3.sup.0 1.4 0.1 0.1 C.sub.3.sup.= 46.3 46.2
46.0 C.sub.4 18.5 18.9 18.7 C.sub.5.sup.+ 5.4 5.1 4.8 Coke 0.5 0.4
0.4
EXAMPLE 9
[0110] The synthesis of Example 3 was repeated with the molar ratio
of DEDMP/TMAA in the synthesis mixture varying between 0.33 and
19. The results of .sup.13C MAS NMR analysis for detecting the presence
of DEDMP (the AEI directing agent) and TMAA (the CHA directing agent),
expressed in molar ratios, in the as-synthesized products, as well
as the percentage of faulted chards observed in 500 chards by BF-TEM
analysis are shown in the following table, together with the results
for the as-synthesized material from Example 3.
6 DEDMP/TMAA in synthesis gel 1 3 5.67 13 C NMR analysis 0/100
8/92 30/70 DEDMP/TMAA in as- synthesized crystals Faulted Chards
by TEM 0 3 27 (% in 500 chards)
[0111] The as-synthesized products of Example 9 together with
the as-synthesized material from Example 3 were individually pressed
to pellets at 30000 psig (2.07.times.10.sup.5 kPa) and then ground
and sieved to between 80 and 125 .mu.m. Two separate samples of
both of the sized materials were weighed between 21 and 22 mg and
mixed separately with 90 mg of 100 .mu.m silicon carbide. These
mixtures were loaded into separate 1.9 mm internal diameter tubes
sealed at the bottom with a quartz frit. The tubes were sealed into
heated reactor blocks and the catalysts were then calcined at 540.degree.
C. under flowing air for 2 hours to effect organic template removal.
The calcined catalysts were then subjected to a mixture of 85% methanol
in N.sub.2 at 540.degree. C., approximately 100 weight hourly space
velocity (WHSV), and 40 psia (276 kPa) methanol partial pressure.
During the methanol reactions the reactor effluents were collected
and stored at timed intervals for analysis by gas chromatography.
Following the methanol reaction the catalysts were subjected to
a flow of 50% oxygen in nitrogen at 550.degree. C. for approximately
90 minutes to burn off deposited coke. The reactor effluents were
analyzed by infrared spectroscopy with quantitation of both carbon
monoxide and carbon dioxide to determine the amounts of coke deposition.
[0112] Selectivities to hydrocarbon products were calculated for
each reaction. The values given below are the individual point selectivities
obtained 30 seconds after the start of the methanol reaction for
each catalyst. These values represent the points of maximum olefin
selectivity for each catalyst. Each value represents an average
of the selectivities obtained from the two individual repeats.
7 DEDMP/TMAA Ratio in Synthesis Gel Selectivity 0.33 1 3 5.67 9
19 C.sub.1 2.5 2.4 2.2 2.4 2.1 1.2 C.sub.2.sup.0 0.4 0.4 0.3 0.3
0.3 0.3 C.sub.2.sup.= 42.0 42.5 43.5 41.2 38.8 33.8 C.sub.3.sup.0
0.3 0.3 0.2 0.1 0.1 0.3 C.sub.3.sup.= 35.3 35.2 35.1 36.9 39.3 43.1
C.sub.4 13.7 13.5 13.4 14.1 14.7 16.1 C.sub.5.sup.+ 4.6 4.6 4.2
4.4 4.2 4.7 Coke 1.2 1.3 1.0 0.6 0.5 0.5
EXAMPLE 10
[0113] The as-synthesized material from Example 7 was pressed to
a pellet at 30000 psig (2.07.times.10.sup.5 kPa) and then ground
and sieved to between 80 and 125 .mu.m. Two separate samples of
the sized material were weighed between 21 and 22 mg and mixed separately
with 90 mg of 100 .mu.m silicon carbide. These mixtures were loaded
into separate 1.9 mm internal diameter tubes sealed at the bottom
with a quartz frit. The tubes were sealed into heated reactor blocks
and the catalysts were then calcined at 540.degree. C. under flowing
air for 2 hours to effect organic template removal. The calcined
catalysts were then subjected to a mixture of 85% methanol in N.sub.2
at 540.degree. C., approximately 100 weight hourly space velocity
(WHSV), and 40 psia (276 kPa) methanol partial pressure for 25 minutes.
During the methanol reaction the reactor effluents were collected
and stored at timed intervals for analysis by gas chromatography.
Following the methanol reaction the catalysts were subjected to
a flow of 50% oxygen in nitrogen at 550.degree. C. for approximately
90 minutes to burn off deposited coke. The reactor effluents were
analyzed by infrared spectroscopy with quantitation of both carbon
monoxide and carbon dioxide to determine the amounts of coke deposition.
[0114] Selectivities to hydrocarbon products were calculated. The
values given below are averages of each individual selectivity over
the entire reaction. Each value represents an average of the selectivities
obtained from the two individual repeats.
8 Product Selectivity C.sub.1 2.9 C.sub.2.sup.0 0.3 C.sub.2.sup.=
41.6 C.sub.3.sup.0 0.1 C.sub.3.sup.= 36.0 C.sub.4 13.7 C.sub.5.sup.+
3.9 Coke 1.3
[0115] 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. |