Chemistry of inorganic compounds – Zeolite – Structure defined x-ray diffraction pattern
Reexamination Certificate
2000-11-03
2002-07-16
Sample, David (Department: 1755)
Chemistry of inorganic compounds
Zeolite
Structure defined x-ray diffraction pattern
C423S705000, C423S708000, C208S046000
Reexamination Certificate
active
06419895
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to an aluminosilicate zeolite having the BPH topology and designated UZM-4. The UZM-4 composition is structurally related to zeolite Q, but is thermally stable up to a temperature of 600° C. and has higher Si/Al ratios in the range of about 1.5 to about 4.0.
BACKGROUND OF THE INVENTION
Zeolites are crystalline aluminosilicate compositions which are microporous and which are formed from corner sharing AlO
2
and SiO
2
tetrahedra. Numerous zeolites, both naturally occurring and synthetically prepared are used in various industrial processes. Zeolites are characterized by having pore openings of uniform dimensions, having a significant ion exchange capacity, and being capable of reversibly desorbing an adsorbed phase which is dispersed throughout the internal voids of the crystal without significantly displacing any atoms which make up the permanent zeolite crystal structure.
One particular zeolite, designated zeolite Q, was first disclosed in U.S. Pat. No. 2,991,151. The general formula for zeolite Q is represented in terms of mole ratio of the oxides by the following:
0.95±0.05 M
2
O:Al
2
O
3
:2.2±0.05 SiO
2
:x
H
2
O
where M designates at least one exchangeable cation, n represents the valence of M and x has a value from 0 to about 5. The examples in the patent are prepared with M being potassium. Synthesis of zeolite Q was conducted at 25° C. to 50° C. After activation at about 130° C., zeolite Q was found to adsorb small polar molecules.
In a paper by John D. Sherman entitled, “Identification and Characterization of Zeolites Synthesized in the K
2
O—Al
2
O
3
—SiO
2
—H
2
O System,”
Molecular Sieves—II
(102) 30, 1974, he reports that the zeolite Q of the '151 patent is the same zeolite as zeolite K-I reported by other researchers. Zeolite K-I was first reported by S. P. Zhdanov and M. E. Ovsepyon in
Doklady Chemistry. Proc. Acad. Sci. USSR,
156, 756 (1964). M. E. Ovsepyan and S. P. Zhdanov further reported on K-I zeolite in
Bull. Acad. Sci. USSR, Chem. Sci.
1, 8 (1965). R. M. Barrer et al. in J. Chem. Soc. (A) 2475 (1968) showed that K-I decomposed at 168° C. It is also reported by Sherman and other researchers that zeolite Q is unstable above 130° C. and is totally disintegrated at 200° C. Owing to this thermal instability, zeolite Q has received little industrial interest. K. J. Andries et al., in
Zeolites,
11, 124 (1991) proposed the BPH topology for zeolite Q. Synthesis of a pure form of zeolite Q was reported by K.J. Andries et al., in
Zeolites,
11, 116 (1991). Finally, U.S. Pat. No. 5,382,420 discloses a composition designated ECR-33, which is a partially rare earth (La) exchanged zeolite Q. In all of the above reports, the Si/Al ratio is 1.
Applicants have now synthesized a zeolite designated UZM-4, which appears to have a similar topology to that of zeolite Q, i.e., BPH, but has considerably different characteristics. The biggest difference is that UZM-4 has been synthesized with higher Si/Al ratios than zeolite Q, starting from a low of about 1.5 and going higher. The most important characteristic of UZM-4 is the greater thermal stability associated with the higher Si/Al ratios. UZM-4 in its various forms is stable to at least 400° C. and often up to greater than 600° C. The x-ray diffraction pattern of UZM-4 is noticeably different from that of zeolite-Q; and UZM-4 has smaller cell dimensions than that of zeolite Q, consistent with its higher Si/Al ratio.
SUMMARY OF THE INVENTION
As stated, the present invention relates to a new aluminosilicate zeolite designated UZM-4. Accordingly, one embodiment of the invention is a microporous crystalline zeolite having a three-dimensional framework of at least AlO
2
and SiO
2
tetrahedral units and an empirical composition on an as synthesized and anhydrous basis expressed by an empirical formula of:
M
m
n+
R
r
p+
Al
1−x
E
x
Si
y
O
z
where M is at least one exchangeable cation selected from the group consisting of alkali and alkaline earth metals, “m” is the mole ratio of M to (Al+E) and varies from about 0.05 to about 0.95, R is at least one organic cation selected from the group consisting of protonated amines, protonated diamines, quaternary ammonium ions, diquaternary ammonium ions, protonated alkanolamines, and quaternized alkanolammonium ions, “r” is the mole ratio of R to (Al+E) and has a value of about 0.05 to about 0.95, “n” is the weighted average valence of M and has a value of about 1 to about 2, “p” is the weighted average valence of R and has a value of about 1 to about 2, E is an element selected from the group consisting of gallium, iron, boron, chromium, indium and mixtures thereof, “x” is the mole fraction of E and has a value from 0 to about 0.5, “y” is the mole ratio of Si to (Al+E) and varies from about 1.5 to about 4 and “z” is the mole ratio of O to (Al+E) and has a value determined by the equation:
z=
(
m·n+r·p+
3+4·
y
)/2
and is characterized in that it has the x-ray diffraction pattern having the d spacings and intensities set forth in Table A:
TABLE A
2-&thgr;
d(Å)
I/I
0
%
6.45-6.75
13.69-13.08
m
7.52-7.80
11.75-11.33
vs
14.75-15.06
6.00-5.88
w-m
15.30-15.66
5.79-5.65
w
18.70-19.05
4.74-4.66
w-m
20.23-20.51
4.39-4.33
w-m
21.30-21.61
4.17-4.11
m
24.00-24.34
3.70-3.65
m
26.56-26.96
3.35-3.30
w-m
27.47-27.80
3.24-3.21
w-m
28.56-28.88
3.12-3.09
w
29.95-30.31
2.98-2.95
m
30.84-31.19
2.90-2.87
w
33.70-34.17
2.66-2.62
w
35.45-35.92
2.53-2.50
w
43.46-44.00
2.08-2.06
w
and is thermally stable up to a temperature of about 400° C.
Another embodiment of the invention is a process for preparing the crystalline microporous zeolite described above. The process comprises forming a reaction mixture containing reactive sources of M, R, Al, Si and optionally E at a temperature of about 85° C. to about 225° C., the reaction mixture having a composition expressed in terms of mole ratios of the oxides of:
a
M
2
O:
b
R
2/p
O:1-
c
Al
2
O
3
:c
E
2
O
3
:d
SiO
2
:e
H
2
O
where “a” has a value of about 0.05 to about 1.5, “b” has a value of about 1.0 to about 15, “c” has a value of 0 to about 0.5, “d” has a value of about 2.5 to about 15, “e” has a value of about 25 to about 2500.
Yet another embodiment of the invention is a hydrocarbon conversion process using the above-described zeolite. The process comprises contacting the hydrocarbon with the zeolite at conversion conditions to give a hydroconverted hydrocarbon.
DETAILED DESCRIPTION OF THE INVENTION
Applicants have prepared an aluminosilicate zeolite and substituted versions of the same whose topological structure is related to BPH as described in
Atlas of Zeolite Structure Types,
W. H. Meier, D. H. Olson, and C.H. Baerlocher, editors, Elsevier, (1996), 68-69, which has been designated UZM-4. As will be shown in detail, UZM-4 is different from zeolite Q in a number of its characteristics. The instant microporous crystalline zeolite (UZM-4) has an empirical composition in the as-synthesized form and on an anhydrous basis expressed by the empirical formula:
M
m
n+
R
r
p+
Al
1−x
E
x
Si
y
O
z
where M is at least one exchangeable cation and is selected from the group consisting of alkali and alkaline earth metals. Specific examples of the M cations include but are not limited to lithium, sodium, potassium, rubidium, cesium, calcium, strontium, barium and mixtures thereof. R is an organic cation and is selected from the group consisting of protonated amines, protonated diamines, quaternary ammonium ions, diquaternary ammonium ions, protonated alkanolamines and quaternized alkanolammonium ions. The value of “n” which is the weighted average valence of M varies from about 1 to about 2. The value of “p” which is the weighted average valence of R varies from 1 to about 2. The ratio of silicon to (Al+E) is represented by “y” which varies from about 1.5 to about 4.0. E is an element which is tetrahedrally coordinated, is present in the framework and is selected from the group consisting of gallium, iron, chromium
Lewis Gregory J.
Miller Mark A.
Moscoso Jaime G.
Wilson Ben A.
Molinaro Frank S.
Sample David
Tolomei John G.
UOP LLC
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