Molecular sieve abstract
This invention relates to a novel synthetic porous crystalline
molecular sieve material, MCM-65 to a reaction mixture and method
for its preparation, and to use of the MCM-65 in catalytic conversion
of organic compounds. The crystalline material exhibits a distinctive
X-ray diffraction pattern as shown in Table 1.
Molecular sieve claims
We claim:
1. A synthetic porous crystalline material having an X-ray pattern
including d-spacing and relative intensity values essentially as
set forth in the following table:
2. The crystalline material of claim 1 having a composition comprising
the molar relationship
wherein y is at least about 200 X is a trivalent element, and
Y tetravalent element.
3. The crystalline material of claim 1 having a composition, on
an anhydrous basis and in terms of moles of oxides per 100 moles
of tetravalent element oxide as follows:
wherein M is an alkali or alkaline earth metal, n is the valence
of M, and R' and R" are tetramethyl ammomium hydroxide (TMAOH)
and quinuclidine, respectively.
4. The crystlline material of claim 2 wherein X is a trivalent
element selected from the group consisting of aluminum, boron, iron,
indium, gallium and a combination thereof; and Y is a tetravalent
element selected from the group consisting of silicon, tin, titanium,
germanium, and a combination thereof.
5. The crystalline material of claim 2 wherein X comprises aluminium
and Y comprises silicon.
6. A method of preparing the crystalline material of claim 1 which
comprises: (a) preparing a reaction mixture capable of forming said
material and mixture comprising sources of tetravalent element (Y)
oxide, trivalent element (X) oxide, alkali or alkaline earth metal
(M), organic directing agents R' and R", and water, said reaction
mixture, in terms of mole ratios, having the following composition:
7. The method according to claim 6 wherein said reaction mixture
comprises the following composition ranges:
8. A process for catalytic conversion of a hydrocarbon containing
feedstock which comprises contacting said feedstock under catalytic
conversion conditions with a catalyst comprising an active form
of the crystalline material of claim 1.
9. A synthetic porous crystalline material having an X-ray pattern
including 2 theta, d-spacing and relative intensity values essentially
as set forth in the following table:
10. The crystalline material of claim 9 having a composition comprising
the molar relationship
wherein y is at least about 200 X is a trivalent element, and
Y is a tetravalent element.
11. The crystalline material of claim 9 having a composition, on
an anhydrous basis and in terms of moles of oxides per 100 moles
of tetravalent element oxide as follows:
wherein M is an alkali or alkaline earth metal, n is the valence
of M, and R' and R" are tetramethyl ammonium hydroxide (TMAOH)
and quinuclidine, respectively.
12. The crystalline material of claim 10 wherein X is a trivalent
element selected from the group consisting of aluminum, boron, iron,
indium, gallium and a combination thereof; and Y is a tetravalent
element selected from the group consisting of silicon, tin, titanium,
germanium, and a combination thereof.
13. The crystalline material of claim 10 wherein X comprises aluminium
and Y comprises silicon.
14. A method of preparing the crystalline material of claim 9 which
comprises: (a) preparing a reaction mixture capable of forming said
material and mixture comprising sources of tetravalent element (Y)
oxide, trivalent element (X) oxide, alkali or alkaline earth metal
(M), organic directing agents R' and R", and water, said reaction
mixture, in terms of mole ratios, having the following composition:
15. The method according to claim 14 wherein said reaction mixture
comprises the following composition ranges:
16. A process for catalytic conversion of a hydrocarbon containing
feedstock which comprises contacting said feedstock under catalytic
conversion conditions with a catalyst comprising an active form
of the crystalline material of claim 9.
17. A calcined synthetic porous crystalline material having an
X-ray pattern including d-spacing and relative intensity values
essentially as set forth in Table 2 of specification.
18. The crystalline material of claim 17 having a composition comprising
the molar relationship
wherein y is at least about 200 X is a trivalent element, and
Y is a tetravalent element.
19. The crystalline material of claim 17 having a composition,
on an anhydrous basis and in terms of moles of oxides per 100 moles
of tetravalent element oxide as follows:
wherein M is an alkali or alkaline earth metal, n is the valence
of M, and R' and R" are tetramethyl ammonium hydroxide (TMAOH)
and quinuclidine, respectively.
20. The crystalline material of claim 18 wherein X is a trivalent
element selected from the group consisting of aluminum, boron, iron,
indium, gallium and a combination thereof; and Y is a tetravalent
element selected from the group consisting of silicon, tin, titanium,
germanium, and a combination thereof.
21. The crystalline material of claim 18 wherein X comprises aluminium
and Y comprises silicon.
22. A method of preparing the crystalline material of claim 17
which comprises: (a) preparing a reaction mixture capable of forming
said material and mixture comprising sources of tetravalent element
(Y) oxide, trivalent element (X) oxide, alkali or alkaline earth
metal (M), organic directing agents R' and R", and water, said
reaction mixture, in terms of mole ratios, having the following
composition:
23. The method according to claim 22 wherein said reaction mixture
comprises the following composition ranges:
24. A process for catalytic conversion of a hydrocarbon containing
feedstock which comprises contacting said feedstock under catalytic
conversion conditions with a catalyst comprising an active form
of the crystalline material of claim 17.
25. A calcined synthetic porous crystalline material having an
X-ray pattern including d-spacing and relative intensity essentially
as shown in FIG. 2 or FIG. 4 of specification.
26. The crystalline material of claim 25 having a composition comprising
the molar relationship
wherein y is at least about 200 X is a trivalent element, and
Y is a tetravalent element.
27. The crystalline material of claim 25 having a composition,
on an anhydrous basis and in terms of moles of oxides per 100 moles
of tetravalent element oxide as follows:
wherein M is an alkali or alkaline earth metal, n is the valence
of M, and R' and R" are tetramethyl ammonium hydroxide (TMAOH)
and quinuclidine respectively.
28. The crystalline material of claim 26 wherein X is a trivalent
element selected from the group consisting of aluminum, boron, iron,
indium, gallium and a combination thereof; and Y is a tetravalent
element selected from the group consisting of silicon, tin, titanium,
germanium, and a combination thereof.
29. The crystalline material of claim 26 wherein X comprises aluminium
and Y comprises silicon.
30. A method of preparing the crystalline material of claim 25
which comprises: (a) preparing a reaction mixture capable of forming
said material and mixture comprising sources of tetravalent element
(Y) oxide, trivalent element (X) oxide, alkali or alkaline earth
metal (M), organic directing agents R' and R", and water, said
reaction mixture, in terms of mole ratios, having the following
composition:
31. The method according to claim 30 wherein said reaction mixture
comprises the following composition ranges:
32. A process for catalytic conversion of a hydrocarbon containing
feedstock which comprises contacting said feedstock under catalytic
conversion conditions with a catalyst comprising an active form
of the crystalline material of claim 25.
33. An as-synthesized synthetic porous crystalline material having
an X-ray pattern including d-spacing and relative intensity essentially
as shown in FIG. 1 or FIG. 3 of specification.
Molecular sieve description
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a novel synthetic crystalline molecular
sieve material, MCM-65 a process for its preparation and its use
in hydrocarbon conversion.
2. Description of the Prior Art
Zeolitic materials, both natural and synthetic, have been demonstrated
in the past to have catalytic properties for various types of hydrocarbon
conversion. Certain zeolitic materials are ordered, porous crystalline
aluminosilicates having a definite crystalline structure as determined
by X-ray diffraction, within which there are a large number of smaller
cavities which may be interconnected by a number of still smaller
channels or pores. These cavities and pores are uniform in size
within a specific zeolitic material. Since the dimensions of these
pores are such as to accept for adsorption molecules of certain
dimensions while rejecting those of larger dimensions, these materials
have come to be known as "molecular sieves" and are utilized
in a variety of ways to take advantage of these properties.
Zeolites typically have uniform pore diameters of about 3 Angstrom
to about 10 Angstrom. The chemical composition of zeolites can vary
widely but they typically consist of SiO.sub.2 in which some of
the Si atoms may be replaced by tetravalent atoms such as Ti or
Ge, by trivalent atoms such as Al, B, Ga, Fe, or by bivalent atoms
such as Be, or by a combination thereof. When there is substitution
by bivalent or trivalent atoms, cations such as Na, K, Ca, NH.sub.4
or H are also present.
Zeolites include a wide variety of positive ion-containing crystalline
aluminosilicates. These aluminosilicates can be described as a rigid
three-dimensional framework of SiO.sub.4 and AlO.sub.4 in which
the tetrahedra are cross-linked by the sharing of oxygen atoms whereby
the ratio of the total aluminum and silicon atoms to oxygen atoms
is 1:2. The electrovalence of the tetrahedra containing aluminum
is balanced by the inclusion in the crystal of a cation, for example,
an alkali metal, an alkaline earth metal cation, or an organic species
such as a quaternary ammonium cation. This can be expressed wherein
the ratio of aluminum to the number of various cations, such as
Ca/2 Sr/2 Na, K or Li is equal to unity. One type of cation may
be exchanged either entirely or partially by another type of cation
utilizing ion exchange techniques in a conventional manner. By means
of such cation exchange, it has been possible to vary the properties
of a given aluminosilicate by suitable selection of the cation.
The spaces between the tetrahedra are usually occupied by molecules
of water prior to dehydration.
Prior art techniques have resulted in the formation of a great
variety of synthetic aluminosilicates. These aluminosilicates have
come to be designated by letter or other convenient symbols, as
illustrated by zeolite A (U.S. Pat. No. 2882243), zeolite X (U.S.
Pat. No. 2882244), zeolite Y (U.S. Pat. No. 3130007), zeolite
ZK-5 (U.S. Pat. No. 3247195), zeolite ZK-4 (U.S. Pat. No. 3314752),
zeolite ZSM-5 (U.S. Pat. No. 3702886), zeolite ZSM-11 (U.S. Pat.
No. 3709979), and zeolite ZSM-12 (U.S. Pat. No. 3832449).
The ZSM-52 and its boron-containing analog, ZSM-55 are described
in U.S. Pat. Nos. 4985223 and 5063037 respectively.
U.S. Pat. No. 4637923 describes the porous crystalline material
MCM-47 and its synthesis from a reaction mixture containing a diethylated,
linear diquatemary ammonium compound as the directing agent. U.S.
Pat. No. 5068096 discloses a method for preparing MCM-47 using
bis(methylpyrrolidinium)-DIQUAT-4 as the directing agent. Accordingly,
the synthesis of zeolite MCM-47 has required long dimeric templates
containing diquaternary ammonium compounds.
In contrast, the present invention utilizes a monomeric directing
agent rather than dimeric diquat agents, and provides a new crystalline
material that has excellent porosity and much improved thermal stability.
SUMMARY OF THE INVENTION
The present invention is directed to a novel synthetic crystalline
molecular sieve composition, named MCM-65 comprising a crystal
having a framework topology characterized by a distinctive X-ray
diffraction pattern substantially as set forth in Table 1 below.
In addition, the invention resides in a process for the synthesis
of MCM-65 and to the use of MCM-65 in catalytic conversion of organic
compounds, e.g., hydrocarbon compounds.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 illustrates the X-ray diffraction pattern of as-synthesized
MCM-65 prepared in Example 1;
FIG. 2 illustrates the X-ray diffraction pattern of calcined MCM-65
prepared in Example 1;
FIG. 3 is the X-ray diffraction pattern of as-synthesized MCM-65
prepared in Example 2; and
FIG. 4 is the X-ray diffraction pattern of calcined MCM-65 prepared
in Example 2.
DETAILED DESCRIPTION OF THE PRESENT INVENTION
The synthetic porous crystalline material of this invention, MCM-65
is a single crystalline phase which, in its calcined form, has an
X-ray diffraction pattern which is distinguished from the patterns
of other known as-synthesized or thermally treated crystalline materials
by the lines listed in Table 1 below.
TABLE 1 d-spacing (.ANG.) Relative Intensity 8.98 .+-. 0.25 vs
6.92 .+-. 0.20 w-m 6.81 .+-. 0.42 m-s 6.11 .+-. 0.34 vw 3.46 .+-.
0.11 vw-w 3.40 .+-. 0.22 vw-w 1.84 .+-. 0.14 vw
These X-ray diffraction data were collected with a Scintag diffraction
system, equipped with a germanium solid state detector, using copper
K-alpha radiation. The diffraction data were recorded by step-scanning
at 0.02 degrees of two-theta, where theta is the Bragg angle, and
a counting time of 10 seconds for each step. The interplanar spacing,
d's, were calculated in Angstrom units, and the relative intensities
of the lines, I/I.sub.0 is one-hundredth of the intensity of the
strongest line, above background, were derived with the use of a
profile fitting routine (or second derivative algorithm). The intensities
are uncorrected for Lorentz and polarization effects. The relative
intensities are given in terms of the symbols vs=very strong (80-100),
s=strong (60-80), m=medium (40-60), w=weak (20-40), vw=very weak
(0-20). It should be understood that diffraction data listed for
this sample as single lines may consist of multiple overlapping
lines which under certain conditions, such as differences in crystallographic
changes, may appear as resolved or partially resolved lines. Typically,
crystallographic changes can include minor changes in unit cell
parameters and/or a change in crystal symmetry, without a change
in the structure. These minor effects, including changes in relative
intensities, can also occur as a result of differences in cation
content, framework composition, nature and degree of pore filling,
crystal size and shape, preferred orientation and thermal and/or
hydrothermal history.
In its as-synthesized form, MCM-65 has an X-ray diffraction pattern
which is similar to that of MCM-47 but the peak intensities are
different. Upon calcination, the as-synthesized material transforms
into MCM-65 having a distinctive X-ray diffraction pattern including
the lines of Table 1. In addition, MCM-47 is not thermally stable,
whereas MCM-65 of the present invention is thermally stable.
The porous crystalline material MCM-65 has a composition involving
the molar relationship:
wherein X is a trivalent element, such as aluminum, boron, iron,
indium and/or gallium, preferably aluminum; Y is a tetravalent element,
such as silicon, tin and/or germanium, preferably silicon; and y
is at least about 200 usually from about 400 to greater than about
3000 more usually from about 500 to about 3000.
The MCM-65 can be synthesized in a relatively wide range of X.sub.2
O.sub.3 /YO.sub.2 mole ratios in the presence of combined quinuclidine
and tetramethylammonium organic directing agent. In the synthesized
form, the crystalline material has a composition, in terms of moles
of anhydrous oxides per 100 moles of tetravalent element oxide as
follows:
wherein X and Y are as defined above, M is an alkali or alkaline
earth metal, n is the valence of M, and R' and R" are the directing
agents tetramethyl ammonium hydroxide (TMAOH) and quinuclidine,
respectively.
The original alkali or alkaline earth metal cations of the as synthesized
crystalline material can be replaced with another cation 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 precursors, e.g., ammonium,
ions and mixtures thereof. Particularly preferred cations are those
which render the new zeolite catalytically active, especially for
hydrocarbon conversion. These include hydrogen, rare earth metals
and metals of Groups 2 3 4 6 9 11 12 13 and 14 of the Periodic
Table (New Notation). A typical ion exchange technique would be
to contact the synthetic zeolite with an aqueous solution of a salt
of the desired replacing cation or cations. Examples of such salts
include the halides, e.g., chloride, nitrates and sulfates.
The crystalline material of the invention may be subjected to treatment
to remove part or all of the organic constituents. This conveniently
effected by thermal treatment in which the as-synthesized material
is calcined at a temperature of at least about 370.degree. C. for
at least 1 minute and generally not longer than 20 hours. While
subatmospheric pressure can be employed for the calcination, atmospheric
pressure is desired for reasons of convenience. The calcination
can be performed at a temperature up to about 925.degree. C., preferably
from about 450.degree. C. to about 700.degree. C. The calcined product,
especially in its metal, hydrogen and ammonium forms, is particularly
useful in the catalysis of certain organic, e.g., hydrocarbon, conversion
reactions.
The crystalline material of this invention, when employed either
as an adsorbent or as a catalyst in an organic compound conversion
process should be dehydrated, at least partially. This can be done
by heating to a temperature in the range of 200.degree. C. to about
370.degree. C. in an atmosphere such as air, nitrogen, etc., and
at atmospheric, subatmospheric or superatmospheric pressures for
between 30 minutes and 48 hours. Dehydration can also be performed
at room temperature merely by placing the MCM-65 in a vacuum, but
a longer time is required to obtain a sufficient amount of dehydration.
The MCM-65 of the present invention can be prepared from a reaction
mixture containing water and sources of an alkali or alkaline earth
metal oxide (M), an oxide of trivalent element (X), an oxide of
tetravalent element (Y), and the directing agents tetramethyl ammonium
hydroxide (R') and quinuclidine (R"). The reaction mixture,
in terms of mole ratios of oxides, preferably has the following
composition ranges:
Reactants Useful Preferred YO.sub.2 /X.sub.2 O.sub.3 10 to .infin.
300 to .infin. H.sub.2 O/YO.sub.2 5 to 1000 10 to 200 OH.sup.- /YO.sub.2
0.1 to 2.0 0.20-1.00 M.sub.2/n/ YO.sub.2 0.05 to 2.0 0.10 to 0.80
R'/Y 0.05 to 2.0 0.2 to 1.0 R"/Y 0.05 to 2.0 0.2 to 1.0
The crystallization is carried out under either static or stirred
conditions, e.g., in an autoclave or static bomb reactor, at a temperature
from about 80 to about 220.degree. C., more preferably from about
160.degree. C. to about 180.degree. C., for a time sufficient for
crystallization to occur at the temperature used, e.g., from about
24 hrs to about 30 days; more preferably about 96 hrs to about 120
hrs. Thereafter, the crystals are separated from the liquid and
recovered. The composition can be prepared utilizing materials which
supply the appropriate oxide. Such compositions include sodium silicate,
silica hydrosol, silica gel, silicic acid, sodium hydroxide, sodium
chloride, aluminum sulfate, sodium aluminate, aluminum oxide, or
aluminum itself.
Synthesis of the new crystals is facilitated by the presence of
at least 0.001 percent, preferably 0.10 percent and more preferably
1 percent, seed crystals (based on total weight) of crystalline
product.
The calcined MCM-65 has a surface area of from about 100 to about
250 m.sup.2 /g, more typically from about 166 to about 199 m.sup.2
/g, which is indicative of a porous material. In one embodiment,
the material has an alpha value of 6 as determined by the hexane
cracking test. The Alpha Test is described, e.g., in U.S. Pat. No.
3354078 and the Journal of Catalysis, 4:527(1965); 6:278(1966)
and 61:395(1980). Test conditions include a constant temperature
of 538.degree. C. and a variable flow rate as described in Journal
of Catalysis. 61:395.
The composition prepared by the instant invention can be shaped
into a wide variety of particle sizes. Generally speaking, the particles
can be in the form of a powder, a granule, or a molded product,
such as an extrudate having particle size sufficient to pass through
a 2 mesh (Tyler) screen and be retained on a 400 mesh (Tyler) screen.
In cases where the catalyst is molded, such as by extrusion, the
crystals can be extruded before drying or partially dried and then
extruded.
As in the case of many catalysts it may be desired to incorporate
the MCM-65 of the present invention with another material resistant
to the temperatures and other conditions employed in organic conversion
processes. Such materials include active and inactive materials
and synthetic or naturally occurring zeolites as well as inorganic
materials such as clays, silica and/or metal oxides. The latter
may be either naturally occurring or in the form of gelatinous precipitates
or gels including mixtures of silica and metal oxides. Use of a
material in conjunction with the composition of the present invention,
i.e., combined therewith which is active, tends to improve the conversion
and/or selectivity of the catalyst in certain organic conversion
processes. Inactive materials suitably serve as diluents to control
the amount of conversion in a given process so that products can
be obtained economically and orderly without employing other means
for controlling the rate of reaction. These materials may be incorporated
into naturally-occurring clays, e.g., bentonite and kaolin, to improve
the crush strength of the catalyst under commercial operating conditions.
Such material, i.e., clays, oxides, etc., function as binders or
matrix for the catalyst. It is desirable to provide a catalyst having
good crush strength because in a petroleum refinery the catalyst
is often subjected to rough handling, which tends to break the catalyst
down into powder-like materials, which cause problems in processing.
These clay binders have been employed normally only for the purpose
of improving the crush strength of the catalyst. It is desirable
to provide a catalyst having good crush strength because in a petroleum
refinery the catalyst is often subjected to rough handling, which
tends to break the catalyst down into powder-like materials which
cause problems in processing.
Naturally-occurring clays which can be composited with the crystal
of the present invention include montmorillonite and kaolin families.
These families include subbentonites, and kaolins commonly known
as Dixie, McNamee, Georgia and Florida clays or others in which
the main mineral constituent is hallyosite, kaolinite, dickite,
nacrite, or anauxite. Such clays can be used in the raw state as
originally mined or initially subjected to calcination, acid treatment
or chemical modification. Binders useful for compositing with the
crystal of the present invention also include inorganic oxides,
notably alumina.
In addition to the foregoing materials, the aluminosilicate molecular
sieve of the present invention can be composited with a porous matrix
material such as silica-alumina, silica-magnesia, silica-zirconia,
silica-thoria, silica-beryllia, silica-titania as well as ternary
compositions such as silica-alumina-thoria, silica-alumina-zirconia,
silica-alumina-magnesia and silica-magnesia-zircorna.
Catalyst compositions containing the material of the invention
will generally comprise from about 1% to 90% by weight of MCM-65
and from about 10% to 99% by weight of the binder or matrix material.
More preferably, such catalyst compositions will comprise from about
2% to 80% by weight of MCM-65 and from about 20% to 98% by weight
of the matrix.
The MCM-65 crystalline molecular sieve of the present invention
can also be used as a catalyst in intimate combination with an additional
hydrogenating component such as tungsten, vanadium, molybdenum,
rhenium, nickel, cobalt, chromium, manganese, or a noble metal such
as platinum or palladium where a hydrogenation-dehydrogenation function
is to be performed. Such component can be exchanged into the composition,
to the extent as in the structure, impregnated therein or physically
intimately admixed therewith. Such component can be impregnated
in or onto it such as, for example, by, in the case of platinum,
treating the crystal with a solution comprising platinum metal-containing
ions. Thus, suitable platinum compounds include chloroplatinic acid,
platinous chloride and various compounds containing the platinum
amine complex.
Employing a catalytically active form of the composition of this
invention which contains a hydrogenation component, reforming stocks
can be reformed employing a temperature from about 300.degree. C.
to about 600.degree. C. The pressure can be from about 100 to about
1000 psig but is preferably from about 200 to about 700 psig. The
liquid hourly space velocity is generally from about 0.1 to about
10 preferably from about 0.5 to about 4 and the hydrogen to hydrocarbon
mole ratio is generally from about 1 to about 20 preferably from
about 4 to about 12.
The catalyst made from the zeolite of the present invention can
also be used for reducing the pour point of gas oils. This reduction
is carried out at a liquid hourly space velocity between about 10
and about 30 and a temperature between about 400.degree. C. and
about 600.degree. C.
Other reactions which can be accomplished employing the catalyst
made from the zeolite of this invention with or without a metal,
e.g., platinum, or palladium, include hydrogenation-dehydrogenation
reactions and desulfurization reactions, olefin polymerization (oligomerization),
aromatic alkylation with C.sub.2 -C.sub.12 olefins or with C.sub.1
-C.sub.12 alcohols, isomerization of olefins and aromatics, disproportionation
and transalkylation of alkylaromatics and other organic compound
conversions such as the conversion of alcohols (e.g., methanol)
to hydrocarbons. |