Molecular sieve abstract
The present invention relates to a mesoporous molecular sieve MPL-1
and its preparation process. The anhydrous composition of this molecular
sieve contains at least three elements, i.e. aluminum, phosphorus
and oxygen. The molecular sieve has larger pore diameters, generally
1.3 nm-10.0 nm, a larger specific surface area and adsorption capacity.
It is synthesized under the hydrothermal process with an organic
compound as template. Where necessary, silicon and/or titanium may
be added to synthesize the aluminosilicophosphate, aluminotitanophosphate,
or aluminosilicotitanophosphate molecular sieves having a mesoporous
structure, and/or metal compounds may be added to synthesize derivatives
of mesoporous aluminophosphate molecular sieves containing the corresponding
hetero-atoms.
Molecular sieve claims
1. A mesoporous molecular sieve comprising at least three elements,
i.e. phosphorus, aluminum, and oxygen, wherein the P.sub.2O.sub.5/Al.sub.2O.su-
b.3 molar ratio is 0.5-1.5; and having a X-ray diffraction pattern
on which its strongest diffraction peak is at the position 2.theta.=1.5.degree.-3.0.degree.
with the units d-spacing greater than 4.0 nm.
2. The mesoporous molecular sieve according to claim 1 wherein
the pore diameter of the molecular sieve is 1.3 nm-10.0 nm.
3. The mesoporous molecular sieve according to claim 2 wherein
said pore diameter is 2.0 nm-10.0 nm.
4. The mesoporous molecular sieve according to claim 2 wherein
said pore diameter is 2.0 nm-5.0 nm.
5. The mesoporous molecular sieve according to claim 1 wherein
said P.sub.2O.sub.5/Al.sub.2O.sub.3 molar ratio is 0.7-1.3.
6. The mesoporous molecular sieve according to claim 1 wherein
said P.sub.2O.sub.5/Al.sub.2O.sub.3 molar ratio is 0.7-1.0.
7. The mesoporous molecular sieve according to claim 1 wherein
said molecular sieve further comprises elements Si and/or Ti, wherein
T/Al.sub.2O.sub.3 molar ratio is 0.01-2.0 wherein T represents
Si and/or Ti.
8. The mesoporous molecular sieve according to claim 7 wherein
said T/Al.sub.2O.sub.3 molar ratio is 0.01-1.0 wherein T represents
Si and/or Ti.
9. The mesoporous molecular sieve according to claim 7 wherein
said molecular sieve further comprises one or more other metal elements
in addition to the elements aluminum and/or titanium, and the molar
ratio of said other metal element(s) to alumina M/Al.sub.2O.sub.3=0.01-2.0
wherein M represents the other metal element(s).
10. The mesoporous molecular sieve according to claim 9 wherein
said molar ratio of other metal element(s) to alumina M/Al.sub.2O.sub.3=0.01-1-
.0 wherein M represents the other metal element(s).
11. The mesoporous molecular sieve according to claim 9 wherein
said molar ratio of other metal element(s) to alumina M/Al.sub.2O.sub.3=0.1-0.-
5 wherein M represents the other metal element(s).
12. The mesoporous molecular sieve according to claim 1 wherein
said interplanar distance of the strongest diffraction peak d=4.0-6.0
nm.
13. The mesoporous molecular sieve according to claim 1 wherein
said molecular sieve has substantively the same X-ray diffraction
pattern as shown in FIG. 1.
14. The mesoporous molecular sieve according to claim 1 wherein
said molecular sieve has a pore volume of 0.30 ml/g-1.00 ml/g, and
a specific surface area of 300 m.sup.2/g-1000 m.sup.2/g.
15. The mesoporous molecular sieve according to claim 1 wherein
said molecular sieve has a pore volume of 0.40 ml/g-0.70 ml/g, and
a specific surface area of 500 m.sup.2/g-800 m.sup.2/g.
16. The mesoporous molecular sieve according to claim 1 wherein
per 100 g of said molecular sieve has adsorption capacity towards
benzene of more than 10 g at 25.degree. C. and P.sub.S/P.sub.O=0.016
and per 100 g of said molecular sieve has adsorption capacity towards
water of more than 50 g at 25.degree. C. and P.sub.S/P.sub.O=0.026.
17. The mesoporous molecular sieve according to claim 16 wherein
per 100 g of said molecular sieve has adsorption capacity towards
benzene of 12 g-25 g at 25.degree. C. and P.sub.S/P.sub.O=0.016
and per 100 g of said molecular sieve has adsorption capacity towards
water of 52 g-70 g at 25.degree. C. and P.sub.S/P.sub.O=0.026.
18. The mesoporous molecular sieve according to claim 1 wherein
said molecular sieve is so thermally and hydrothermally stable that
its crystal lattice is not damaged after being calcined at 700.degree.
C. for 2 h, and its crystallinity is not substantively decreased
after being heated in boiling water for 10 h.
19. The mesoporous molecular sieve according to claim 9 wherein
said metal element(s) is one or more selected from the group consisting
of La, Ce, Ti, Ni, Co, Cr, Ca, Cu, Zn, Mg and Fe.
20. A process for preparation of the molecular sieve according
to claim 1 comprising the steps of: (a) mixing a template, an aluminum
source, and a phosphorus source with water, stirring the mixture
and adjusting the pH value of the mixture to 6-11 wherein the molar
ratios of various materials P.sub.2O.sub.5/Al.sub.2O.sub.3=0.5-1.5
H.sub.2O/Al.sub.2O.sub.- 3=50-500 R/Al.sub.2O.sub.3=0.2-2.0 where
R is a template; (b) crystallizing the resulting mixture from step
(a) to form a precipitate recovering and washing and drying the
solid product to obtain the as-synthesised mesoporous molecular
sieve, and (c) calcining the as-synthesised molecular sieve to remove
the template to obtain the molecular sieve.
21. The process according to claim 20 wherein the molar ratios
of various materials in the mixture P.sub.2O.sub.5/Al.sub.2O.sub.3-0.7-1.3
H.sub.2O/Al.sub.2O.sub.3=100-400 and R/Al.sub.2O.sub.3=0.3-1.0
wherein R is a template.
22. The process according to claim 20 wherein the molar ratio
of phosphorus to aluminum in the mixture P.sub.2O.sub.5/Al.sub.2O.sub.3=0.7--
1.0.
23. The process according to claim 20 wherein one or more silicon
sources and/or titanium sources is optionally added in step (a)
to allow the T/Al.sub.2O.sub.3 molar ratio in the mixture to be
0.01-2.0 wherein T represents Si and/or Ti.
24. The process according to claim 23 wherein said T/Al.sub.2O.sub.3
molar ratio is 0.01-1.0 wherein T is Si and/or Ti.
25. The process according to claim 23 wherein said T/Al.sub.2O.sub.3
molar ratio is 00.1-0.5 wherein T is Si and/or Ti.
26. The process according to claim 20 wherein other metal source(s)
in addition to the aluminum sources are optionally added where necessary
to allow the M/Al.sub.2O.sub.3 molar ratio in the mixture obtained
in step (a) to be 0.01-2.0 wherein M represents the other metal
element(s).
27. The process according to claim 20 wherein other metal source(s)
in addition to the aluminum sources are optionally added where necessary
to allow the M/Al.sub.2O.sub.3 molar ratio in the mixture obtained
in step (a) to be 0.01-1.0 wherein M represents the other metal
element(s).
28. The process according to claim 20 wherein other metal source(s)
in addition to the aluminum sources are optionally added where necessary
to allow the M/Al.sub.2O.sub.3 molar ratio in the mixture obtained
in step (a) to be 0.1-0.5 wherein M represents the other metal
element(s).
29. The process according to claim 20 wherein said aluminum source
is one or more selected from the group consisting of active aluminas
and their precursors, soluble aluminum salts and organic aluminium-containing
compounds.
30. The process according to claim 20 wherein said phosphorus
source may be an inorganic and/or organic compound containing phosphorus.
31. The process according to claim 20 wherein said phosphorus
source is orthophosphoric acid, phosphoric acid, pyrophosphoric
acid, phosphorus trichloride, phosphorus oxychloride, and/or phosphate.
32. The process according to claim 20 wherein said phosphorus
source is ortho-phosphoric acid.
33. The process according to claim 20 wherein said silicon source
is one or more selected from the group consisting of silica sol,
white carbon black, water glass, and ortho-silicate.
34. The process according to claim 20 wherein said titanium source
is one or more selected from the group consisting of TiO.sub.2
TiF.sub.4 TiCl.sub.4 TiOCl.sub.2 Ti(SO.sub.4).sub.2 tetramethyl
titanate, tetraethyl titanate, tetrapropyl titanate, and the derivatives
thereof.
35. The process according to claim 26 wherein said other metal
source(s) is one selected from the group consisting of the compounds
of La, Ce, Ti, Ni, Co, Cr, Ca, Cu, Zn, Mg and Fe, or a mixture thereof.
36. The process according to claim 35 wherein said metal source(s)
is soluble metal salt(s).
37. The process according to claim 36 wherein said metal source(s)
is one or more selected from the group consisting of the nitrate,
sulfate, acetate and chloride of the metal(s).
38. The process according to claim 20 wherein said template may
be represented by the general formula: R.sub.1R.sub.2R.sub.3R.sub.4NX,
wherein R.sub.1 R.sub.2 R.sub.3 and R.sub.4 independently represent
a substituting group, N represents element nitrogen or phosphorus,
and X represents hydroxyl or halogen.
39. The process according to claim 38 wherein said halogen is
selected from the group consisting of F, Cl, Br, and l, or the mixture
thereof.
40. The process according to claim 38 wherein at least one substituting
group among R.sub.1 R.sub.2 R.sub.3 and R.sub.4 is that having
5 or more carbon atoms.
41. The process according to claim 38 wherein at least one substituting
group among R.sub.1 R.sub.2 R.sub.3 and R.sub.4 is that containing
one or more polar functional groups.
42. The process according to claim 41 wherein said functional
group is selected from the group consisting of amino, hydroxyl,
carboxyl, sulfhydryl, aldehyde group, or halogen.
43. The process according to claim 20 wherein said template is
a mixture of phenethoxy-2-hydroxypropyl trimethylammonium chloride
(PTMAC) and/or phenethoxy-2-hydroxypropyl trimethylammonium bromide
(PTMAB) with other organic compounds capable to serve as a template.
44. The process according to claim 20 wherein said template is
phenethoxy-2-hydroxypropyl trimethylammonium chloride (PTMAC) and/or
phenethoxy-2-hydroxypropyl trimethylammonium bromide (PTMAB).
45. The process according to claim 20 wherein the pH value of
said mixture in step (a) is 7-10.
46. The process according to claim 20 wherein the pH value of
said mixture in step (a) is 7.5-9.0.
47. The process according to claim 20 wherein the substance used
to adjust the pH value of the mixture is an acid, base and/or salt
capable of adjusting acidity and alkalinity.
48. The process according to claim 47 wherein said base is an
inorganic alkali or organic alkali.
49. The process according to claim 47 wherein said base is selected
from the group consisting of sodium hydroxide, potassium hydroxide,
aqueous ammonia, primary amines, secondary amines, tertiary amines
and quaternary ammonium alkali.
50. The process according to claim 49 wherein said base is selected
from the group consisting of aqueous ammonia and quaternary ammonium
alkali.
51. The process according to claim 20 wherein said crystallization
temperature in step (b) is 100.degree. C.-200.degree. C. and the
crystallization time is 4-240 h.
52. The process according to claim 51 wherein said the temperature
is 130.degree. C.-170.degree. C., and the time period is 24-96 h.
53. The process according to claim 20 wherein said calcination
temperature in step (c) is 450.degree. C.-700.degree. C., and calcination
time is 2-24 h.
54. The process according to claim 53 wherein said calcination
temperature is 500.degree. C.-650.degree. C., and calcination time
is 4-8 h.
Molecular sieve description
TECHNICAL FIELD
[0001] The present invention relates to a molecular sieve, especially
a mesoporous molecular sieve, and a process for the preparation
of the same.
BACKGROUND OF THE INVENTION
[0002] Porous inorganic materials have been widely applied in the
catalysis and adsorption separation fields mainly because these
materials possess an abundant microporous structure and a larger
specific surface area and can provide a great number of acid sites
and active adsorption sites. These materials may be roughly classified
into amorphous and crystalline and modified pillared-layer materials.
[0003] Amorphous materials are important catalyst supports which
have been used in industry for many years. The most typical one
is amorphous silica-alumina, which is an acidic catalyst and an
important support of the reforming catalyst in petrochemical industry.
Here "amorphous" means that the long range is disordered
but the short range is generally ordered. The most commonly used
methods for characterizing these materials are X-ray diffraction,
pore structure analysis and transmission electronic microscopy.
The appearance of porous crystalline materials has enlarged the
categories of the porous materials, and greatly enriched theory
of the porous materials and brought the petrochemical industry a
revolution. Especially since the application of the porous crystalline
materials in industry results in astonishing economic benefits,
people have been carrying out deeper and more perfect investigations
on the porous crystalline materials. Porous crystalline materials
possess a unique, regular crystalline structure, and each has a
pore structure with a definite shape and size. Micropores connect
the pores to form "giant molecules" with abundant pores.
Since such a pore structure only permits the molecule with a definite
size to pass, this material is referred to as "molecular sieve"
and this property of molecular sieves has been widely applied. The
structure of these molecular sieves, no matter whether they are
synthetic or natural, generally has three-dimensional framework
structure., Those kinds of molecular sieves only contain Si, Al
and O elements are customarily denoted as "zeolite". Presently,
many kinds of zeolites have been synthesized and widely applied,
such as zeolite-A (U.S. Pat. No. 2882243), zeolite-X (U.S. Pat.
No. 2882244), zeolite-Y (U.S. Pat. No. 3130007), ZSM-5 (U.S.
Pat. No. 3702886), ZSM-11 (U.S. Pat. No. 3709979), etc. If Al
or/and Si in the zeolites are partly or entirely substituted by
other atoms, new types of molecular sieves will be formed. Now a
variety of new types of molecular sieves have been synthesized and
widely applied, such as SAPO series molecular sieves (U.S. Pat.
Nos. 6162415 5370851 5279810 5230881 4440871 etc.),
especially the SAPO-11 molecular sieves (U.S. Pat. Nos. 6204426
6111160 5833837 5246566 4921594 4499315). Because
these molecular sieves have a unique activity for the isomerization
of long-chain alkanes, they are ideal components for the hydroisomerization
of the wax in the lubricant oil fraction, and are widely used in
the production of the basic oil of the top-grade lubricant oil.
[0004] Although the study on molecular sieves is quite mature,
the pore diameters of most prepared molecular sieves are below 1.0
nm, and the maximum pore diameter reported in a literature is only
1.3 nm (Davis M E, Saldarriaga C, et al. Nature, 1991 352: 320).
Such molecular sieve still belongs to the micropore one which restricts
the reaction of larger molecules. According to the definition of
IUPAC, the material with pore diameter below 2 nm belongs to the
microporous materials, and the material with pore diameter in the
range of 2 nm to 50 nm belongs to the mesoporous material. Based
on this definition, most of the prior molecular sieves belong to
the microporous molecular sieves. Due to the development of the
modern industry, the stricter and stricter environment protection
law, and the worldwide tendency for the crude oil to become worse
and heavier, it is an urgent task to develop a series of novel materials
with super larger pore diameter and specific surface area, stable
properties and excellent adsorptive and catalytic performances.
[0005] U.S. Pat. Nos. 5108725 5102643 5098684 and 5057296
disclose a process for synthesizing a mesoporous MCM-41 molecular
sieve and its properties. This sort of molecular sieve has a structure
of symmetric hexagonal. Its higher surface area, uniform pore distribution,
adjustable pore diameter and acidity, accessible active sites, small
diffusion resistance, ability to provide favorable space and effective
acidic active sites for the large molecules, especially the heavy
oil organic molecules to conduct the shape-selective reaction in
the processes of petrochemical industry greatly encourage the chemical
engineers. However, since the synthesis of such a molecular sieve
requires large amounts of organic templates and auxiliary organic
compounds such as cetyl trimethylammonium bromide (CTMAB), quaternary
ammonium alkali and other organic compounds, and the resulting molecular
sieve has so poor thermal stability (especially hydrothermal stability)
that its crystal lattice can be retained in boiling water for only
several hours or even shorter, it would be hard for them to have
any value for practical applications.
[0006] Through the effort of recent years, some new mesoporous
materials have been synthesized, but most of these materials are
the improvements of MCM-41 which are, for example, synthesized by
using new processes (U.S. Pat. Nos. 6190639 6096287 5958368
and 5595715 and Chinese Patent (Application) ZL 99103705.7 96193321.6
and 95192999.2). Some hetero-atom substituted MCM-41 are synthesized
(U.S. Pat. Nos. 6193943 6054052 6042807 5855864 and
5783167 and Chinese Patent (Application) ZL.95105905.X, and 99107789.X)
and thick wall MCM-41 is also synthesized (U.S. Pat. No. 6193943).
However, the problem of the poor hydrothermal stability has not
been substantively solved in these arts.
THE DISCLOSURE OF THE PRESENT INVENTION
[0007] To overcome the shortages and problems of the above techniques,
an object of the present invention is to provide a molecular sieve
(hereinafter names it MPL-1), which has a character of mesoporous
structure, larger and distribution concentrated pore diameters,
larger specific surface and adsorption capacity, high thermal and
hydrothermal stabilities, Meanwhile, a further object of the present
invention is to provide a process for preparing such a molecular
sieve.
[0008] The mesoporous molecular sieve provided by the present invention
comprises at least three elements, i.e. phosphorus, aluminum, and
oxygen, wherein the P.sub.2O.sub.5/Al.sub.2O.sub.3 molar ratio is
0.5-1.5 preferably 0.7-1.3 and most preferably 0.7-1.0 and has
a specific X-ray diffraction pattern.
[0009] The molecular sieve according to the present invention has
a X-ray diffraction pattern on which its strongest diffraction peak
is at the position 2.theta.=1.5.degree.-13.0.degree. with the units
d-spacing greater than 4.0 nm, preferably 4.0 nm-6.0 nm. Particularly,
the molecular sieve according to the present invention has substantively
the same X-ray diffraction pattern as shown in FIG. 1.
[0010] The molecular sieve of the present invention has a pore
diameter of 1.3 nm-10.0 nm, preferably 2.0 nm-10.0 nm, and most
preferably 2.0 nm-5.0 nm.
[0011] The molecular sieve of the present invention may further
contain elements Si and/or Ti, wherein the T/Al.sub.2O.sub.3 molar
ratio is 0.01-2.0 preferably 0.01-1.0 wherein T represents Si
and/or Ti.
[0012] Besides aluminum and/or titanium, the molecular sieve of
the present invention may further contain one or more other metal
elements. The molar ratio of said other metal(s) to alumina M/Al.sub.2O.sub.3=0.01--
2.0 preferably 0.01-1.0 and most preferably 0.1-0.5 wherein M
represents the other metal element(s).
[0013] The molecular sieve of the present invention has a pore
volume of 0.30 ml/g-1.00 ml/g, preferably 0.40 ml/g-0.70 ml/g; and
a specific surface area of 300 m.sup.2/g-1000 m.sup.2/g, preferably
500 m.sup.2/g-800 m.sup.2/g.
[0014] The molecular sieve of the present invention has excellent
adsorption capacities towards benzene and water. Particularly, every
100 g of said molecular sieve has adsorption capacity towards benzene
of more than 10 g, preferably 12 g-25 g at 25.degree. C. and P.sub.S/P.sub.O=0.016
and every 100 g of said molecular sieve has adsorption capacity
towards water of more than 50 g, preferably 52 g-70 g at 25.degree.
C. and P.sub.S/P.sub.O=0.026.
[0015] The molecular sieve of the present invention has higher
thermal and hydrothermal stabilities. Its crystal lattice is not
damaged after being calcined at 700.degree. C. for 2 h and its crystallinity
is not substantively decreased after being heated in boiling water
for 10 h.
[0016] The other metal element in addition to aluminum, which may
be used in the molecular sieve of the present invention, is one
or more selected from the group consisting of La, Ce, Ti, Ni, Co,
Cr, Ca, Cu, Zn, Mg, and Fe.
[0017] The molecular sieve of the present invention may be prepared
by a process comprising the steps of:
[0018] (a) mixing a template, an aluminum source, and a phosphorus
source with water, stirring the mixture and adjusting the pH value
of the mixture to 6-11 wherein the molar ratio of various materials
is P.sub.2O.sub.5/Al.sub.2O.sub.3=0.5-1.5 preferably 0.7-1.3 and
most preferably 0.7-1.0; H.sub.2O/Al.sub.2O.sub.3=50-500 preferably
100-400; R/Al.sub.2O.sub.3=0.2-2.0 preferably 0.3-1.0 where R
is a template;
[0019] (b) crystallizing the resulting mixture of step (a) to form
a precipitate, recovering and washing and drying the solid product
to obtain the as-synthesised molecular sieve; and
[0020] (c) calcining the as-synthesised molecular sieve of step
(b) to remove the template to obtain the mesoporous molecular sieve
of the present invention.
[0021] In the above synthetic process, it is possible to selectively
add, where necessary, one or more silicon sources and titanium sources
to step (a) to allow the T/Al.sub.2O.sub.3 molar ratio in the mixture
obtained in step (a) to be 0.01-2.0 preferably 0.01-1.0 more preferably
0.1-0.5. Furthermore, it is possible to selectively add, where necessary,
other metal sources in addition to the aluminum sources to allow
the M/Al.sub.2O.sub.3 molar ratio in the mixture obtained in step
(a) to be 0.01-2.0 preferably 0.01-1.0 and most preferably 0.1-0.5
wherein M represents the other metal element(s).
[0022] In the above synthetic process of the present invention
the aluminum source is one or more selected from the group consisting
of active aluminas and their precursors, soluble aluminum salts
and organic aluminium-containing compounds; said phosphorus source
may be inorganic or organic compounds containing phosphorus, such
as orthophosphoric acid, phosphorous acid, pyrophosphoric acid,
phosphorus trichloride, phosphorus oxychloride, and phosphates,
etc., preferably orthophosphoric acid; said silicon source is generally
one or more selected from the group consisting of silica sol, white
carbon black, water glass and ortho-silicate; the titanium source
is one or more selected from the group consisting of TiO.sub.2
TiF.sub.4 TiCl.sub.4 TiOCl.sub.2 Ti(SO.sub.4).sub.2 tetramethyl
titanate, tetraethyl titanate, and tetrapropyl titanate, and the
derivatives thereof.
[0023] In the above process, said other metal source other than
aluminum prefers the soluble salts such as one or more metal-containing
compounds selected from the group consisting of the nitrate, sulfate,
acetate and chloride of La, Ce, Ti, Ni, Co, Cr, Ca, Cu, Zn, Mg and
Fe.
[0024] The template used in the above synthetic process may be
represented by the general formula: R.sub.1R.sub.2R.sub.3R.sub.4NX,
wherein R.sub.1 R.sub.2 R.sub.3 and R.sub.4 independently represent
a substituting group, N represents element nitrogen or phosphorus,
and X represents hydroxyl or halogen such as F, Cl, Br, or l. Besides,
at least one substituting group among said R.sub.1 R.sub.2 R.sub.3
and R.sub.4 is a group containing 5 or more carbon atoms, such as
cetyl trimethylammonium chloride (CTMAC), cetyl trimethylammonium
bromide (CTMAB), octadecyl trimethylammonium salts. It is preferred
that at least one substituting group among R.sub.1 R.sub.2 R.sub.3
and R.sub.4 contains one or more polar functional groups, which
can be selected from a group consisting of amino, hydroxyl, carboxyl,
sulfhydryl, aldehyde group, and halogens such as F, Cl, Br or l.
The most preferred ones are phenethoxy-2-hydroxypropyl trimethylammonium
chloride (PTMAC) and/or phenethoxy-2-hydroxypropyl trimethylammonium
bromide (PTMAB) or a mixture of phenethoxy-2-hydroxypro- pyl trimethylammonium
chloride (PTMAC) and/or phenethoxy-2-hydroxypropyl trimethylammonium
bromide (PTMAB) with other organic compounds capable of serving
as a template.
[0025] The pH value of said mixture in step (a) of the above process
is preferably 7-10 and more preferably 7.5-9.0. The substances
used to adjust the pH of the mixture may include any substance capable
of adjusting acidity and alkalinity such as acids, alkalis or salts,
preferably inorganic or organic alkalis such as sodium hydroxide,
potassium hydroxide, aqueous ammonia, primary amines, secondary
amines, tertiary amines, or quaternary ammonium alkali, more preferably
quaternary ammonium alkali and/or aqueous ammonia.
[0026] In step (b) of the synthetic process of the present invention,
said crystallization temperature is 100.degree. C.-200.degree. C.,
preferably 130.degree. C.-170.degree. C., and the crystallization
time is 4 h-240 h, preferably 24 h-96 h; said calcination temperature
in step (c) is 450.degree. C.-700.degree. C., preferably 500.degree.
C.-650.degree. C., and calcination time is 2 h-24 h, preferably
4 h-8 h.
[0027] Compared to the prior art, the present invention has the
following advantages: The mesoporous molecular sieve according to
the present invention has larger and distribution concentrated pore
diameters, larger specific surface area and adsorption capacity,
higher thermal and hydrothermal stabilities, moderate and adjustable
acidity and amount of the acid. It can be directly used as a catalyst
or a support with special function and can provide a great number
of active sites and space for reaction and reduce the diffusion
resistance of reactants and products, thereby raising the activity
and selectivity of the reaction. Therefore, it is a support of catalyst
and adsorbent with excellent performance, and has great value for
potential application. Besides, the templates used in the synthetic
process of the mesoporous molecular sieve provided by the present
invention are a sort of organic compounds with special structure.
The present invention has the advantages that the process is simple
and the operation is easy. |