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 values as set forth in Table 1 of the specification.
2. The crystalline material of claim 1 having a composition comprising
the molar relationship X.sub.2O.sub.3:(y)YO.sub.2wherein y is at
least about 200 X is a trivalent element, and Y is a tetravalent
element.
3. The crystalline material of claim 2 having a composition, on
an anhydrous basis and in terms of moles of oxides per 100 moles
of tetravalent element oxide as follows: (0-20)R'.sub.20:(0-20)R".sub.2O:
(0 to 5) (0 to 20)M.sub.2/nO: (0 to 2)X.sub.2O.sub.3: (100)YO.sub.2
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
4. The crystalline 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:
6 YO.sub.2/X.sub.2O.sub.3: 10 to .infin., H.sub.2O/YO.sub.2: 5
to 1000 OH.sup.-/YO.sub.2: 0.1 to 2 M.sub.2/n/YO.sub.2: 0.05 to
2 R'/Y: 0.05 to 2 and R"/Y: 0.05 to 2
wherein n is the valence of the alkali or alkaline earth metal
M, and R' and R" are quinuclidine and tetramethylammonium respectively;
and (b) maintaining said mixture under crystallization conditions
until crystals of said crystalline material are formed.
7. The method according to claim 6 wherein said reaction mixture
comprises the following composition ranges:
7 YO.sub.2/X.sub.2O.sub.3: 300 to .infin., H.sub.2O/YO.sub.2: 10
to 200 OH.sup.-/YO.sub.2: 0.2 to 1 M.sub.2/n/YO.sub.2: 0.1 to
0.8 R'/Y: 0.2 to 1 and R"/Y: 0.2 to 1.
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.
Molecular sieve description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims priority to application Ser. No.
60/253245 filed Nov. 27 2000 and PCT/US01/43849 filed Nov. 14
2001 which are hereby incorporated by reference.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] This invention relates to a novel synthetic crystalline
molecular sieve material, MCM-65 a process for its preparation
and its use in hydrocarbon conversion.
[0004] 2. Description of the Prior Art
[0005] 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.
[0006] 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.
[0007] 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.
[0008] 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).
[0009] The ZSM-52 and its boron-containing analog, ZSM-55 are
described in U.S. Pat. Nos. 4985223 and 5063037 respectively.
[0010] 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.
[0011] 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
[0012] 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.
[0013] 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
[0014] FIG. 1 illustrates the X-ray diffraction pattern of as-synthesized
MCM-65 prepared in Example 1;
[0015] FIG. 2 illustrates the X-ray diffraction pattern of calcined
MCM-65 prepared in Example 1;
[0016] FIG. 3 is the X-ray diffraction pattern of as-synthesized
MCM-65 prepared in Example 2; and
[0017] FIG. 4 is the X-ray diffraction pattern of calcined MCM-65
prepared in Example 2.
DETAILED DESCRIPTION OF THE PRESENT INVENTION
[0018] 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.
1 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
[0019] 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.
[0020] 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.
[0021] The porous crystalline material MCM-65 has a composition
involving the molar relationship:
X.sub.2O.sub.3:y(YO.sub.2)
[0022] 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.
[0023] The MCM-65 can be synthesized in a relatively wide range
of X.sub.2O.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:
[0024] (0-20)R'.sub.20:(0-20)R".sub.2O: (0 to 5) (0 to 20)M.sub.2/nO:
(0 to 2)X.sub.2O.sub.3: (100)YO.sub.2
[0025] 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.
[0026] 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.
[0027] 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.
[0028] 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.
[0029] 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:
2 Reactants Useful Preferred YO.sub.2/X.sub.2O.sub.3 10 to .infin.
300 to .infin. H.sub.2O/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
[0030] 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.
[0031] 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.
[0032] 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.
[0033] 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.
[0034] 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.
[0035] 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.
[0036] 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.
[0037] 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.
[0038] 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.
[0039] 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.
[0040] 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.
[0041] 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.
[0042] 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.
[0043] The following non-limiting examples further illustrate the
present invention.
EXAMPLE 1
[0044] 35 g of colloidal silica (30 wt. % SiO.sub.2), Al(OH).sub.3
NaOH (20 wt. % solution), quinuclidine (solid), TMAOH (25 wt. %
solution) and distilled water were combined in the following molar
ratios:
3 Si/Al.sub.2 500 H.sub.2O/Si 30 OH/Si 0.35 Na/Si 0.15 TMAOH/Si
0.2 Quinuclidine/Si 0.2
[0045] The combined mixture was added to a stirred autoclave and
heated to 180.degree. C. at 100 rpm for 96 hours. The product was
then filtered and washed with water. The as-synthesized material
was calcined at a temperature of 540.degree. C. to yield the new
material designed as MCM-65. The powder patterns of the as-synthesized
and calcined materials are given in FIGS. 1 and 2 respectively.
The surface area of the resultant crystalline material was 199 m.sup.2/g.
EXAMPLE 2
[0046] 35 g of colloidal silica (30 wt. % SiO.sub.2), Al(OH).sub.3
NaOH (20 wt. % solution), quinuclidine, TMAOH (25 wt. % solution)
and distilled water were combined in the following molar ratios:
4 Si/Al.sub.2 2000 H.sub.2O/Si 30 OH/Si 0.35 Na/Si 0.15 TMAOH/Si
0.20 Quinuclidine/Si 0.20
[0047] The combined mixture was added to a stirred autoclave and
heated to 180.degree. C. at 100 rpm for 96 hours. The product was
then filtered and washed with water. The as-synthesized material
was calcined at a temperature of 540.degree. C. to yield the new
material designated as MCM-65. The powder patterns of the as-synthesized
and calcined materials are given in FIGS. 3 and 4 respectively.
The surface area of the resultant crystalline material was 166 m.sup.2/g.
[0048] Table 2 lists the relative intensities of the peaks in the
powder pattern for the calcined material MCM-65 of Examples 1 and
2. |