U.S. patent application number 10/526353 was filed with the patent office on 2006-01-19 for catalyst for epoxidation reactions.
This patent application is currently assigned to BASF Aktiengesellschaft. Invention is credited to Peter Babler, Hans- Georg Gobbel, Georg Krug, Ulrich Mueller, Peter Rudolf, Joaquim Benrique Teles.
Application Number | 20060014629 10/526353 |
Document ID | / |
Family ID | 31991705 |
Filed Date | 2006-01-19 |
United States Patent
Application |
20060014629 |
Kind Code |
A1 |
Mueller; Ulrich ; et
al. |
January 19, 2006 |
Catalyst for epoxidation reactions
Abstract
The present invention relates to the manufacture of solid
materials or shaped bodies containing at least one zeolite and
being at least partly crystalline. Furthermore, the present
invention relates to the solid materials or shaped bodies as such
and to the use of these materials for reactions of compounds having
at least one C--C double bond with at least one hydroperoxide.
Specifically, the present invention relates to a process for the
manufacture of a solid material containing at least one zeolite and
being at least partly crystalline, wherein the synthesis of the
said solid material involves at least one partial step of
contacting at least one transition metal oxide source with at least
one epoxide or hydrolysate thereof prior to or during the at least
partial crystallization of said solid material.
Inventors: |
Mueller; Ulrich; (Neustadt,
DE) ; Krug; Georg; (Morlenbach, DE) ; Babler;
Peter; (Viernheim, DE) ; Gobbel; Hans- Georg;
(Kallstadt, DE) ; Rudolf; Peter; (Ladenburg,
DE) ; Teles; Joaquim Benrique; (Otterstadt,
DE) |
Correspondence
Address: |
OBLON, SPIVAK, MCCLELLAND, MAIER & NEUSTADT, P.C.
1940 DUKE STREET
ALEXANDRIA
VA
22314
US
|
Assignee: |
BASF Aktiengesellschaft
Ludwigshafen
DE
67056
|
Family ID: |
31991705 |
Appl. No.: |
10/526353 |
Filed: |
September 15, 2003 |
PCT Filed: |
September 15, 2003 |
PCT NO: |
PCT/EP03/10241 |
371 Date: |
March 2, 2005 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
10243669 |
Sep 16, 2002 |
6884743 |
|
|
10526353 |
Mar 2, 2005 |
|
|
|
Current U.S.
Class: |
502/64 |
Current CPC
Class: |
C07D 301/12 20130101;
B01J 29/89 20130101 |
Class at
Publication: |
502/064 |
International
Class: |
B01J 29/06 20060101
B01J029/06 |
Claims
1-19. (canceled)
20. A process for preparing a solid material for use as catalytic
material in an epoxidation reaction, the solid material comprising
at least one zeolite and being at least partially crystalline,
wherein a step (I) of an at least partial crystallization of at
least one solid material comprising at least one zeolite out of a
synthesis mixture involves at least one partial step of contacting
at least one transition metal oxide source with at least one
epoxide or hydrolysate thereof prior to or, during the at least
partial crystallization of said synthesis mixture into said solid
material, and wherein the at least one epoxide is the product of
said epoxidation reaction.
21. The process according to claim 20, wherein step (I) comprises
at least the following partial steps (Ia) mixing at least one
hydrolyzable silicon source with a mineralizing and/or structuring
agent and water; (Ib) mixing at least one transition metal oxide
source with an epoxide or a hydrolysate thereof; (Ic) mixing the
mixtures from (Ia) and (Ib) so that at least a part of the
hydrolyzable compounds hydrolyzes; (Id) distilling at least part of
the alcohol that has been formed as a result of the at least
partial hydrolisation of at least part of the hydrolyzable
compounds; (Ie) adding water to the bottom of (Id); (If) reacting
the synthesis mixture resulting from (Ie) at a temperature elevated
with respect to room temperature.
22. The process according to claim 21, wherein the hydrolyzable
silicon source comprises at least one silicon oxide, the
mineralizing and/or structuring agent comprises at least one
tetraalkylammonium hydroxide, and the transition metal oxide source
comprises at least one titanate.
23. The process according to claim 22, wherein the hydrolyzable
silicon source comprises at least tetraethoxy silicate, the
mineralizing and/or structuring agent comprises at least
tetrapropylammonium hydroxide, the transition metal oxide source
comprises at least tetrabutylorthotitanate and the epoxide or the
hydrolysate thereof comprises at least propylene oxide or propylene
glycol.
24. The process according to claim 20, wherein the at least one
zeolite belongs to at least one of the following structure classes:
MFI, MEL, MWW, BEA or any mixed structure thereof.
25. The process according to claim 21, wherein the at least one
zeolite belongs to at least one of the following structure classes:
MFI, MEL, MWW, BEA or any mixed structure thereof.
26. The process according to claim 20, step (1) of the at least
partial crystallization resulting in a mixture (I) comprising at
least said solid material and a mother liquor, said process further
comprising the step (II) separating and/or concentrating the solid
material in mixture (I).
27. The process according to claim 21, step (I) of the at least
partial crystallization resulting in a mixture (I) comprising at
least said solid material and a mother liquor, said process further
comprising the step (II) separating and/or concentrating the solid
material in mixture (I).
28. The process according to claim 26, wherein, after step (II), at
least one of the following two additional steps is performed: (W)
bringing the solid material from step (II) in contact with a
composition containing water; (III) agglomerating or granulating or
agglomerating and granulating the solid material from step (W) or
from step (II).
29. The process according to claim 27, wherein, after step (II), at
least one of the following two additional steps is performed: (W)
bringing the solid material from step (II) in contact with a
composition containing water; (III) agglomerating or granulating or
agglomerating and granulating the solid material from step (W) or
from step (II).
30. The process according to claim 28, wherein, after step (W), the
solid material is separated from at least part of the composition
containing water.
31. The process according to claim 26, optionally comprising the
step (III) agglomerating, or granulating, or agglomerating and
granulating the solid material from step (II); said process further
comprising the step (S) shaping the solid material from step (II)
or (III) obtaining a shaped body.
32. The process according to claim 31, wherein the following step
(W) is performed after step (II), or after step (S), or after step
(II) and after step (S) (W) bringing the solid material from step
(II) or the shaped body from step (S) in contact with a composition
containing water.
33. The process according to claim 31, wherein step (S) is selected
from the group consisting of pelletizing, pressing, extruding,
sintering, roasting, and briquetting.
34. Process according to claim 32, wherein step (S) is selected
from the group consisting of pelletizing, pressing, extruding,
sintering, roasting, and briquetting.
35. Process according to claim 33, wherein before, or during, or
before and during the step (S), a binding material is added to said
solid material.
36. Process according to claim 26, wherein after at least one of
the steps (II), (W), (III) or (S), a step (C) of calcining the
solid material, or the shaped body, or the solid material or the
shaped body is performed.
37. Process according to claim 36, wherein step (C) is performed at
temperatures higher than 400.degree. C.
38. Process according to claim 26, wherein the process is an
integrated process.
39. A solid material comprising at least one zeolite for use as
catalytic material in an epoxidation reaction, the solid material
being obtainable by a process of treating a synthesis mixture,
wherein a step (I) of an at least partial crystallization of at
least one solid material comprising at least one zeolite out of a
synthesis mixture involves at least one partial step of contacting
at least one transition metal oxide source with at least one
epoxide or hydrolysate thereof prior to or during the at least
partial crystallization of said synthesis mixture into said solid
material, and wherein the at least one epoxide is the product of
said epoxidation reaction, said step (I) comprising at least the
following partial steps (Ia) mixing at least one hydrolyzable
silicon source with a mineralizing and/or structuring agent and
water; (Ib) mixing at least one transition metal oxide source with
an epoxide or a hydrolysate thereof; (Ic) mixing the mixtures from
(Ia) and (Ib) so that at least a part of the hydrolyzable compounds
hydrolyzes; (Id) distilling at least part of the alcohol that has
been formed as a result of the at least partial hydrolisation of at
least part of the hydrolyzable compounds; (Ie) adding water to the
bottom of (Id); (If) reacting the synthesis mixture resulting from
(Ie) at a temperature elevated with respect to room
temperature.
40. The solid material according to claim 39, wherein the solid
material contains Ti.
41. The solid material according to claim 39, wherein the solid
material is shaped into a shaped body.
42. A process for preparing a solid material for use as catalytic
material in an epoxidation reaction, the solid material comprising
at least one zeolite and being at least partially crystalline,
wherein a step (I) of an at least partial crystallization of at
least one solid material comprising at least one zeolite out of a
synthesis mixture involves at least one partial step of contacting
at least one transition metal oxide source with at least one
epoxide or hydrolysate thereof prior to or during the at least
partial crystallization of said synthesis mixture into said solid
material, and wherein the at least one epoxide is the product of
said epoxidation reaction, wherein step (I) comprises at least the
following partial steps (Ia) mixing at least one hydrolyzable
silicon source with a mineralizing and/or structuring agent and
water; (Ib) mixing at least one transition metal oxide source with
an epoxide or a hydrolysate thereof; (Ic) mixing the mixtures from
(Ia) and (Ib) so that at least a part of the hydrolyzable compounds
hydrolyzes; (Id) distilling at least part of the alcohol that has
been formed as a result of the at least partial hydrolisation of at
least part of the hydrolyzable compounds; (Ie) adding water to the
bottom of (Id); (If) reacting the synthesis mixture resulting from
(Ie) at a temperature elevated with respect to room temperature;
wherein step (I) of the at least partial crystallization resulting
in a mixture (I) comprising at least said solid material and a
mother liquor, said process further comprising the step (II)
separating and/or concentrating the solid material in mixture (I);
optionally comprising the step (III) agglomerating, or granulating,
or agglomerating and granulating the solid material from step (II);
said process further comprising the step (S) shaping the solid
material from step (II) or (III) obtaining a shaped body.
43. A process for preparing a solid material for use as catalytic
material in an epoxidation reaction, the solid material comprising
at least one zeolite and being at least partially crystalline,
wherein a step (1) of an at least partial crystallization of at
least one solid material comprising at least one zeolite out of a
synthesis mixture involves at least one partial step of contacting
at least one transition metal oxide source with at least one
epoxide or hydrolysate thereof prior to or during the at least
partial crystallization of said synthesis mixture into said solid
material, and wherein the at least one epoxide is the product of
said epoxidation reaction, wherein step (I) comprises at least the
following partial steps (Ia) mixing at least one hydrolyzable
silicon source with a mineralizing and/or structuring agent and
water; (Ib) mixing at least one transition metal oxide source with
an epoxide or a hydrolysate thereof; (Ic) mixing the mixtures from
(Ia) and (Ib) so that at least a part of the hydrolyzable compounds
hydrolyzes; (Id) distilling at least part of the alcohol that has
been formed as a result of the at least partial hydrolisation of at
least part of the hydrolyzable compounds; (Ie) adding water to the
bottom of (Id); (If) reacting the synthesis mixture resulting from
(Ie) at a temperature elevated with respect to room temperature;
wherein step (1) of the at least partial crystallization resulting
in a mixture (I) comprising at least said solid material and a
mother liquor, said process further comprising the step (II)
separating and/or concentrating the solid material in mixture (I);
optionally comprising the step (III) agglomerating, or granulating,
or agglomerating and granulating the solid material from step (II);
said process further comprising the step (S) shaping the solid
material from step (II) or (III) obtaining a shaped body; and
wherein the following step (W) is performed after step (II), or
after step (S), or after step (II) and after step (S) (W) bringing
the solid material from step (II) or the shaped body from step (S)
in contact with a composition containing water.
Description
[0001] The present invention relates to the manufacture of solid
materials or shaped bodies containing at least one zeolite and
being at least partly crystalline. Furthermore, the present
invention relates to the solid materials or shaped bodies as such
and to the use of these materials for reactions of compounds having
at least one C--C double bond with at least one hydroperoxide.
Specifically, the present invention relates to a process for the
manufacture of a solid material containing at least one zeolite and
being at least partly crystalline, wherein the synthesis of the
said solid material involves at least one partial step of
contacting at least one transition metal oxide source with at least
one epoxide or hydrolysate thereof prior to or during the at least
partial crystallization of said solid material.
[0002] The synthesis of solid materials containing at least Si and
Ti, in particular of titanium zeolithes used for applications in
catalysis, is of particular commercial importance and has resulted
in a large body of prior art. By way of example, U.S. Pat. No.
4,666,692 and U.S. Pat. No. 4,410,501 are cited in the general
context of the manufacture of titanium silicalites.
[0003] An integrated process for producing solid materials
containing Si and Ti and shaped bodies produced therefrom is
described, e.g. in WO 98/55229.
[0004] The scientific publication "Studies of the synthesis of
titanium silicalite, TS-1" from A. Thangaraj et al. [Zeolites 12
(1992) 943 ff] relates to a procedure to obtain TS-1, wherein the
precipitation of titanium oxide during the hydrolysis of the
alkoxides in the synthesis mixture is minimized or avoided by
adding, in a separate step, isopropyl alcohol to the titanium
source. Not only is it found that the amount of metal oxide
precipitation indeed decreases, but also that more Ti is built into
the silicalite framework. However, said publication is silent as to
the use of other compounds to be added to a transition metal oxide
source and is silent as to the effect such treatment has on the
catalyst actually used in a chemical reaction, e.g. an epoxidation
reaction.
[0005] Referring to said scientific publication, US application
2001/0041162 A1 describes the use of alcohols having a pK.sub.a
value lower than that of water, more specifically the use of
2-ethoxyethanol, in order to avoid precipitation of metal oxides
such as anatase, from the synthesis solution. As a result it is
found that indeed the molar fraction of precipitated Ti in anatase
form is significantly reduced. However, no significant effect on
important performance characteristics of the catalyst actually used
for epoxidation reactions were identified, in particular on epoxide
selectivity.
[0006] The object of the present invention is to provide a
catalyst, and a process for the manufacture thereof which results
in improved performance characteristics of the catalyst based on
zeolite materials, in particular with respect to selectivity and
activity, over the catalysts of the prior art.
[0007] Surprisingly, it has been found that by adding the epoxide
that is the product of the desired catalyzed epoxidation reaction,
or a hydrolysate thereof, to the transition metal oxide source, the
performance characteristics of the catalyst obtained from the
synthesis mixture comprising the transition metal oxide source
treated according to the inventive process, is improved over a
corresponding catalyst which had not been subjected to the
inventive step of adding an epoxide or hydrolysate thereof to the
transition metal oxide source.
[0008] The catalytic material (solid material or shaped body)
obtainable by the inventive process of adding an epoxide or
hydrolysate thereof can be used for any catalytic reaction,
preferably for a catalytic reaction in which it improves at least
one reaction parameter or catalyst performance characteristic, such
as selectivity, yield, activity, over the respective values
obtained using catalytic material that has not been subjected to
the inventive treatment of adding an epoxide or hydrolysate thereof
to the transition metal oxide source.
[0009] Preferably, the catalytic material obtainable by the
inventive process is used in reactions of compounds containing at
least one C--C-double bond with at least one hydroperoxide, i.e. in
epoxidation reactions.
[0010] In the following, a glossary of the most important
expressions used in the context of the present invention are
defined.
[0011] A "synthesis mixture" as used in the context of the present
invention pertains to any mixture which yields, by means of
crystallization, a mixture containing a solid material which is at
least partially crystalline, and a fluid material. Preferably, the
synthesis mixture contains at least a Si source (Si precursor), a
transition metal oxide source (transition metal precursor) and a
mineralizing and/or structure forming agent. In particular,
reference is made to all synthesis mixtures known to the expert in
the field of zeolite preparation, particularly to synthesis
mixtures used for the hydrothermal treatment of gels. The synthesis
mixture may be a sol, gel, solution, or a suspension. The synthesis
mixture may be obtained by mixing two or more separate
solutions.
[0012] "Zeolites" as used in the context of the present invention
are crystalline alumosilicates with well-ordered channel or cage
structures containing micropores. The expression "micropore" as
used in the context of the present invention corresponds to the
definition given in "Pure Applied Chemistry", Vol. 45, p. 71 ff.,
in particular p. 79 (1976). According to this definition,
micropores are pores with a pore diameter of less than 2 nm. The
network of these zeolites is made of SiO.sub.4 and
AlO.sub.4-tetrahedra that are bridged via shared oxygen bonds. An
overview of the known structures can be found in, e.g., W. M. Meier
und D. H. Olson in "Atlas of Zeolite Structure Types", Elsevier,
4.sup.th Ed., London 1996. In addition to micropores, solid
materials or shaped bodies according to the invention may contain
mesopores and/or macropores as well.
[0013] "Solid materials" as obtained, for example, after the
crystallization of the synthesis mixture, are to be understood in
the context of the present invention as any known material which
displays at least the following properties: (i) it contains at
least one zeolite material and (ii) is different from the synthesis
mixture described before in the sense that a separation of said
solid material from its mother liquor is possible and/or
concentrating of the solid material by, e.g., ultra-filtration is
possible. Typically, the solid material prevails as particles
suspended in the mother liquor.
[0014] A "mother liquor" in the context of the present invention is
any liquid phase that may contain an unlimited number of substances
dissolved therein, however in itself is not a solid material. In
particular, the mother liquor may contain adjuvants dissolved
therein. In the sense of the present invention, a mother liquor can
only occur after step (I) of the integrated process as described
above. Typically, a mother liquor is the liquid phase in which the
solid material is suspended in the form of particles. Said mixture
(I) is then subjected to step (II) of separating and/or
concentrating of the solid material in mixture (I).
[0015] The term "epoxide" as used in the context of the present
invention refers to any compound with at least two adjacent carbon
atoms, wherein at least those two carbon atoms are, at least
partly, chemically bound to one mutual oxygen atom. By way of
example, propylene oxide is mentioned. A "hydrolysate" of an
epoxide is the product of the reaction of the epoxide with any
compound leading to hydrolysis, e.g. water. By way of example,
propylene glycol is mentioned as the hydrolysate of the above
mentioned propylene oxide.
[0016] Step (II) of the present invention relates to concentrating
and/or separating of the solid material in the mother liquor and/or
from the mother liquor, wherein the mixture (I) containing the
solid material is obtained from step (I). The term "concentrating
and/or separating is to be understood in the context of the present
invention as any step that at least results in that, at the end of
step (II), the solid material content in the mixture is increased
and/or the solid material is separated partly or entirely from the
mother liquor.
[0017] The complete "separation" of the solid material from the
mixture (the suspension) is explicitly contained in the definition
of "concentrating" as a specific case. Such methods of separating
and/or concentrating include, but are not limited to, spray-drying
or ultra-filtration and will be described in more detail below. The
terms "filtration", "ultra-filtration", and "spray-drying" as well
as other methods of concentrating and/or separating the solid
material from the mother liquor are described in detail in DE 102
32 406.9, the respective content of which is hereby incorporated by
reference.
[0018] A "shaped body" as used in the context of the present
invention is to be understood to be any three-dimensional entity
which can be obtained by any of the shaping steps (S) mentioned
below. The shaped body is obtained in a typical manner by means of
compacting of the solid material described above. Said solid
material may originate from steps (II) and/or (III), using optional
step of calcining (C).
[0019] The expressions "granulating" and "agglomerating" as used in
the context of the present invention are to be seen as synonymous
and describe, respectively, any conceivable process that can be
used to increase the diameter of the particles obtained from step
(II). Said increase of the particle diameter can be achieved by
baking the particles together or by growing on the particles layer
by layer. The process of granulating thereby includes, but is not
limited to, processes taking advantage of the phenomenon of wetting
of the particles by at least one liquid. Furthermore, binding
materials may be added to the mixture in order to enhance or enable
the agglomerating and/or granulating of the particles.
[0020] A "binding material" as used in the context of the present
invention is to be understood to be any material that enables a
physical, chemical, or physical-chemical bond between the
substances constituting the particle. Such binding materials may be
used in the step (S) of shaping or forming the solid material into
a shaped body as well. Reference is made to the description of
binding materials in that context.
[0021] The inventive treatment of adding an epoxide or hydrolysate
thereof to the transition metal oxide source is preferably part of
an integrated process, namely an integrated process producing a
mechanically stable solid material or a shaped body containing at
least one zeolite material. Schematically, such an integrated
process can be characterized by the following steps
[0022] (I) at least partial crystallization of at least one solid
material containing at least one zeolite out of a synthesis
mixture, resulting in mixture (I) containing at least said solid
material and a mother liquor;
[0023] (II) separating and/or concentrating of the solid material
from mixture (I);
[0024] (W) bringing the solid material from step (II) in contact
with a composition containing water;
[0025] (III) agglomerating, or granulating, or agglomerating and
granulating of the solid material from step (W);
[0026] wherein steps (W) and (III) are optional. Step (II) may
additionally include the drying and/or washing of the solid
material, possibly also in several iterations.
[0027] Additionally and/or optionally, the following steps may be
part of the integrated process as well:
[0028] (S) shaping of the solid material into shaped bodies
subsequent to steps (W) or (III);
[0029] (C) Calcining of the solid material and/or the shaped body
at temperatures higher than 400.degree. C.;
[0030] wherein the step (C) of calcining may be performed at least
once after at least one of the following steps of the integrated
process: (II), (W), or (III).
[0031] In a preferred embodiment, step (W) is performed after step
(S) of shaping the solid material.
[0032] In the present application, the inventive solid material
containing at least one zeolite material or the shaped body
obtainable therefrom is discussed in the context of applications in
the field of catalysis. This, however, cannot be construed as a
limitation of the use of the solid material and/or the shaped body
to the field of catalysis. The explicit discussion of examples in
the field of catalysis is illustrative only. The inventive material
may be used in other fields as well.
[0033] In the following, the individual steps of the integrated
process for producing a solid material and/or shaped body are
summarized, wherein the solid material and/or the shaped body
contain(s) at least one zeolite material and is/are at least
partially crystalline. Of particular importance is step (D)
containing the inventive partial step (Ib).
Step I: (Partial) Crystallization of the Synthesis Mixture
[0034] According to the present invention, step (I) of the at least
partial crystallization of at least one solid material containing
at least one zeolite out of a synthesis mixture, resulting in
mixture (I) containing at least said solid material and a mother
liquor comprises at least the following partial steps [0035] (Ia)
mixing of at least one hydrolyzable silicon source with a
mineralizing and/or structuring agent and water; [0036] (Ib) mixing
of at least one transition metal oxide source with an epoxide or a
hydrolysate thereof; [0037] (Ic) mixing of the mixtures from (Ia)
and (Ib) so that at least a part of the hydrolyzable compounds
hydrolyzes; [0038] (Id) distilling at least parts of the alcohol
that has been formed as a result of the at least partial
hydrolysation of at least part of the hydrolyzable compounds;
[0039] (Ie) adding water to the bottom of (Id); [0040] (If)
reacting of the synthesis mixture resulting from (Ie) at a
temperature elevated with respect to room temperature.
[0041] Preferably, steps (Ia) and (Ib) are performed in separate
containers.
[0042] In a preferred embodiment, the hydrolyzable silicon source
comprises at least one silicon oxide, the mineralizing and/or
structuring agent comprises at least one tetraalkylammonium
hydroxide, the transition metal oxide source comprises at least one
titanate and the epoxide or hydrolysate thereof comprises at least
the epoxide or the hydrolysate thereof of the reaction for which
the solid material is ultimately used as a catalyst.
[0043] In a further preferred embodiment, the hydrolyzable silicon
source comprises at least tetraethoxy silicate, the mineralizing
and/or structuring agent comprises at least tetrapropylammonium
hydroxide, the transition metal oxide source comprises at least
tetrabutylorthotitanate, and the epoxide or the hydrolysate thereof
comprises at least propylene oxide or propylene glycol, with
propylene glycol being particularly preferred.
[0044] As far as the at least one zeolite material resulting from
said synthesis step (I) is concerned, no limitations exist.
Preferably, a zeolite containing titanium, zirconium, chromium,
niobium, iron, bor, and/or vanadium is employed. Particularly
preferably, a zeolite containing titanium is employed, wherein
zeolites known to the expert in the field as "titanium silicalites"
(TS) are especially preferred.
[0045] Such zeolites containing titanium, in particular those
having a crystalline structure of the MFI-type as well as ways for
producing them are described, for example, in WO 98/55228, WO
99/55229, WO 99/29426, WO 99/52626, EP-A 0 311 983, or EP-A 405
978. The respective content of these documents is hereby
incorporated by reference. In addition to Si and Ti, said zeolite
materials may contain additional elements, such as aluminum,
zirconium, tin, iron, cobalt, nickel, gallium, bor, or small
amounts of fluorine. It is possible that the titanium of the
zeolite is partly or completely replaced by vanadium, zirconium, or
niobium, or any mixture of two or more of these components.
[0046] Zeolites containing titanium and displaying a MFI-structure
are known to yield a characteristic pattern in X-ray diffraction.
Furthermore, these materials display a vibration band in the
infrared (IR) at approximately 960 cm.sup.-1. Therefore, it is
possible to distinguish the zeolites containing titanium from
crystalline or amorphous TiO.sub.2-phases or from alkali metal
titanates.
[0047] In a further preferred embodiment, the at least one zeolite
material is selected from the following group: zeolites containing
at least one of the following elements: titanium, germanium,
tellurium, vanadium, chromium, niobium, zirconium, particularly
those having a pentasil zeolite structure, in particular the
structural types that can be, via X-ray diffraction, assigned to
the structure types of ABW-, ACO-, AEI-, AEL-, AEN-, AET-, AFG-,
AFI-, AFN-, AFO-, AFR-, AFS-, AFT-, AFX-, AFY-, AHT-, ANA-, APC-,
APD-, AST-, ATN-, ATO-, ATS-, ATT-, ATV-, AWO-, AWW-, BEA-, BIK-,
BOG-, BPH-, BRE-, CAN-, CAS-, CFI-, CGF-, CGS-, CHA-, CHI-, CLO-,
CON-, CZP-, DAC-, DDR-, DFO-, DFT-, DOH-, DON-, EAB-, EDI-, EMT-,
EPI-, ERI-, ESV-, EUO-, FAU-, FER-, GIS-, GME-, GOO-, HEU-, IFR-,
ISV-, ITE-, JBW-, KFI-, LAU-, LEV-, LIO-, LOS-, LOV-, LTA-, LTL-,
LTN-, MAZ-, MEI-, MEL-, MEP-, MER-, MFI-, MWS-, MON-, MOR-, MSO-,
MTF-, MTN-, MTT-, MTW-, MWW-, NAT-, NES-, NON-, OFF-, OSI-, PAR-,
PAU-, PHI-, RHO-, RON-, RSN-, RTE-, RTH-, RUT-, SAO-, SAT-, SBE-,
SBS-, SBT-, SFF-, SGT-, SOD-, STF-, STI-, STT-, TER-, THO-, TON-,
TSC-, VET-, VFI-, VNI-, VSV-, WIE-, WEN-, YUG-, ZON, as well as
mixed structures of at least two or more of the aforementioned
structures. Furthermore, it is conceivable to use zeolites
containing titanium with the structure of ITQ-4, ITQ-9, SSZ-24,
TTM-1, UTD-1, CIT-1 or CIT-5. Further zeolites containing titanium
are such of the structure types ZSM-48 or ZSM-12.
[0048] Zeolites containing titanium of the structure MFI, MEL or
MFI/MEL mixed structures, as well as MWW, BEA or mixed structures
thereof are preferred in the context of the present invention.
Further preferred in the context of the present invention are these
zeolite catalysts containing titanium that are referred to, in
general, as "TS-1", "TS-2" or "TS-3", as well as zeolites
containing titanium having a structure that is isomorphous to
.beta.-zeolite.
[0049] If necessary, or advantageous, additional compounds may be
added. The reaction or mixing of each partial step of step (I) is
performed in an open container or in a pressure-tight container
(autoclave), optionally at elevated temperatures, over the course
of several hours or days. Thereby, a product that is at least
partly crystalline is obtained.
[0050] As far as the duration of the inventive partial step is
concerned, no limitations exist, as long as the partial step
results in an improved performance of the catalyst over a catalyst
that had not been subjected to that partial step. As a measure for
the increased performance, activity, selectivity and/or yield may
be used. Increased mechanical stability or improved properties that
are otherwise relevant for the process of interest can be used as
well. In a preferred embodiment, the inventive partial step (Ib)
consists of mixing the transition metal oxide source with the
epoxide or hydroxide and stirring until the solution is transparent
to the eye.
Step (II): Separating and/or Concentrating
[0051] In step (II) the solid material is separated from the mother
liquor and/or is concentrated in the mother liquor. Step (II) is
performed with mixture (I) from step (I). Methods of separating
and/or concentrating include, but are not limited to, filtration,
ultrafiltration, diafiltration, centrifuge methods, spray drying,
spray granulating, etc.
[0052] This step (II) of concentrating and/or separating is
preferably performed prior to step (W) of bringing the solid
material in contact with a composition containing water and after
the step (I) of crystallizing the solid material. The purpose of
step (II) is to increase the solid content in the mixture resulting
from step (I). For details of filtration and/or concentration,
reference is made to DE 102 32 406.9, the respective content of
which is hereby incorporated by reference.
[0053] Preferably, the solid material is concentrated first and
then separated from the mother liquor by filtration. For example,
the method of ultrafiltration may be used for concentrating the
solid material in the retentate, while the solid material may be
separated from all or parts of the mother liquor by means of
conventional filtration. With respect to conventional filtration,
all methods known to the expert in the art may be used such as cake
filtration or methods involving a centrifuge.
[0054] In another preferred embodiment, step (II) consists of
bringing an inert support body in contact with the synthesis
mixture from step (I). As far as the "inert support body" is
concerned, no limitations exist, as long as the inert support body
does not react noticeably with the synthesis mixture or any
component thereof and said inert support body is capable of
accommodating, at least partly, the solid material contained in the
synthesis mixture from step (I), preferably in the form of a (thin)
film. Such inert support bodies may include, but are not limited
to, beads or pellets made form technical ceramic materials such as
alumosilicate ceramics, alkali alumosilicate ceramics, aluminum
oxide based ceramics (e.g. mullit), magnesium silicates (e.g.
steatit, cordierit). The use of steatit or mullit is preferred.
Said inert support bodies may be porous or dense, wherein the use
of dense support bodies is preferred.
[0055] Said support bodies may be brought in contact with the
synthesis mixture from step (I) by means of all methods known to
expert in the context of bringing a solid body in contact with a
fluid medium. Spraying of the synthesis mixture onto the support
bodies, dipping the support bodies into the synthesis mixture or
saturating/soaking of the inert support bodies in the synthesis
mixture are preferred. In case the method of bringing in contact is
soaking/dipping/saturating, in a preferred embodiment, the
soaked/dipped/saturated support bodies are exposed to an atmosphere
with a partial pressure of the liquid medium of the synthesis
mixture (e.g. water) lower than the pressure of the pure liquid, so
that the liquid medium may, at least partly, evaporate.
[0056] As a result of said step of bringing inert support bodies in
contact with the synthesis mixture from step (I), a (thin) film
containing the solid material containing at least one zeolite and
being at least partly crystalline forms on the support body and/or
in the pores, if the support body is porous. The thickness of the
film so formed may range from 1 .mu.m to 1500 .mu.m. In a preferred
embodiment, the thickness of the film ranges from 5 .mu.m to 50
.mu.m. The result of this embodiment is referred to a "solid
material" in the context of the present invention and is processed
the same way the solid material obtained by spray drying or
ultrafiltration.
[0057] The solid material obtained after step (II) may now be
optionally subjected to at least one step of washing and to at
least one step of drying of the solid material. Furthermore, after
the at least one step of drying, the solid material may also be
calcined at temperatures of 400.degree. C. and higher (see
description of the step (C) of calcining given below).
Step (W): Treatment of the Solid Material With a Composition
Containing Water
[0058] Subsequent to step (II) of concentrating and/or separating,
the solid material may be subjected to a treatment of bringing the
solid material in contact with a composition containing water.
[0059] As far as the term "bringing in contact" is concerned, any
method is conceivable, in which the solid material is brought in
physical contact with a composition containing water. This
includes, but is not limited to: forming a slurry, suspension or
mixture of the solid material in or with the composition containing
water, the composition being preferably in a liquid phase, spraying
the solid material with the composition containing water,
subjecting the solid material to the composition containing water
in the form of vapor and/or steam. It is particularly preferred to
form a slurry of the solid material with the composition containing
water in a stirring tank.
[0060] Preferably, the same stirring tank is used for step (W) that
has already been used for crystallizing the solid material out of
the synthesis mixture. For additional physical contact between the
solid phase and the composition containing water, any means for
stirring or otherwise mechanically acting the mixture containing
the solid material and the composition containing water known to
the expert in this field can be employed. Other methods of mixing
and/or agitating, such as ultrasound agitation, magnetic stirring
and the like are conceivable as well. Preferably the slurry of the
solid material is brought in contact with a composition containing
water in a tank vessel with a mechanical stirring device.
[0061] As far as the composition containing water is concerned, any
substance can be used that contains, at least in parts, water in
any of its modifications. These modifications include the liquid
phase, the solid phase, vapor, steam, super critical water.
Furthermore, the water may by mixed with other substances.
Preferably water is used as such in the liquid phase or as steam.
If water is used in the liquid phase, deionized water is preferred.
Any method to deionize water known to the expert in the art is
included, such as distillation or removing of electrolytes over an
ion exchanger. While not preferred, the use of water containing
salt and/or of water that is acidic or basic is conceivable as
well.
[0062] For specific applications, bringing the solid material in
contact with an aqueous ammonia solution may be preferred. In this
case, a solution of ammonia in water is preferred, wherein the
content of ammonia in water, given in % by weight with respect to
the total weight, ranges from 5 to 60, preferably from 10 to 30. If
a composition containing water and ammonia is used, step (W) is
preferably carried out at pressures elevated with respect to
ambient pressure and not exceeding several hundred bar.
[0063] As far as the ratio between the amount of solid material and
the composition containing water is concerned, no principal
limitations exist, save for the fact that the mixture or slurry
should have viscous or hydraulic properties conducive to mechanical
stirring.
[0064] Furthermore, it is preferred that the treatment of bringing
the solid material in contact with a composition containing water
is performed at a temperature elevated with respect to room
temperature. Temperatures between room temperature and 750.degree.
C. are preferred. Temperatures between 100.degree. C. and
250.degree. C. are particularly preferred, while temperatures
between 120.degree. C. and 175.degree. C. are further
preferred.
[0065] The treatment (W) of the solid material with a composition
containing water can be performed with any type of solid material.
The solid material may be the material obtained from step (II)
without drying or calcining. However, it is preferred that the
solid material from step (II) has been dried and/or calcined before
the treatment. It is further preferred that the solid material has
been washed, dried and optionally calcined prior to step (W). It is
further preferred that the solid material has been obtained by
spray granulation and/or ultrafiltration (in conjunction with
conventional filtering).
[0066] After the optional step (W) has been performed, i.e. after
the solid material has been brought into contact with the
composition containing water, the composition containing water may
be removed from the solid material and/or the solid material may be
concentrated in the composition containing water. To achieve this
end, step (II) may be repeated. This is, the mixture containing the
solid material and composition containing water may be subjected
to, e.g., spray/drying, ultrafiltration, or ultrafiltration in
conjunction with conventional filtration. It may be only subjected
to conventional filtration as well.
Step (III): Agglomerating/Granulating
[0067] Subsequent to step (W), the solid particles can be increased
in their size using any method of agglomerating and/or granulating
known to the expert in the field. For a list of methods used in
this context, reference is made to DE 102 32 406.9, the respective
content of which is hereby incorporated by reference.
Post-Treatment
[0068] In order to improve the catalytic performance of the final
product, subsequent to step (W) or to step (III) or subsequent to
both, it is optionally possible to perform at least one step of
post-treatment of the material, including, but not being limited
to, drying, washing, calcining, treating of the solid material with
a hydrogen peroxide solution. Any combination of these steps is
conceivable as well. It is also possible to treat this solid
material containing at least one zeolite material with compounds
containing alkali metal, in order to transform the zeolitic
material from the H-form into the cationic form. The solid material
obtained after step (W) or after step (III) or after any of the two
steps in conjunction with any of the steps of post treatment
mentioned here, can then be processed further to a shaped body, as
described below.
Step (S): Shaping of the Solid Material
[0069] The starting point for the process to produce a shaped body
containing at least one zeolite is either the solid material after
step (II) or the solid material after step (W) or the solid
material after step (III), optionally involving any of the steps of
post-treatment mentioned in the preceeding paragraph. As it has
been mentioned above, if the process so far has involved at least
one step (W) of bringing the solid material in contact with a
composition containing water, the material obtained after step (S)
does not need to be subjected to a step (W). However, if the solid
material so far has not been subjected to the treatment (W), the
step of bringing the shaped body in contact with at least one
composition containing water has to be performed after the step (S)
of shaping the solid material or after said step (S) in conjunction
with a step (C).
[0070] In any case, the step (S) of shaping the solid material
involves at least one step of forming a three-dimensional material
that contains at least one zeolite material. As far as this
specific (at least one) step of shaping the solid material is
concerned, reference is made to WO 98/55229 and to DE 102 32 406.9
whose respective content is incorporated into the present
application by reference.
[0071] Preferably, a binding material is added to the solid
material resulting from any of the steps mentioned above. Further
adjuvants that may be added to the solid material prior to the step
(S) include, but are not limited to, mixtures containing at least
one alcohol and water, if suitable one or more organic substances
increasing the viscosity, and further substances known from the
prior art.
[0072] Preferably, the solid material is milled and mixed with
silica sol, a dispersion of polystyrene, cellulose and
polyethlylene oxide (PEO), as well as with water. Said mixture is
homogenized in any type of kneading apparatus. In lieu of or in
addition to kneading, any method of bringing the substances into
physical contact may be used. Preferably, the mass obtained by this
method shows plastic flow. The shaped body can then be obtained
from this mass, e.g., by means of molding, in particular extrusion
molding, or by any other method of extrusion known to the expert in
the field.
[0073] As far as the binding materials are concerned, in principle,
every substance can be used that achieves cohesion between the
particles that is increased over the cohesion achieved without the
presence of the binding material. Preferred binding materials are
selected from the group consisting of hydrated silica gel, silicic
acid, tetraalkoxy silicates, tetraalkoxy titanates, tetraalkoxy
zirconates and a mixture of two or more of the afore-mentioned
substances. Tetraalkoxy silicates such as tetramethoxy silicates,
tetraethoxy silicates, tetrapropoxy silicates or tetrabutoxy
silicates are preferred. Tetramethoxy silicates or tetraethoxy
silicates and silica sols are particularly preferred.
[0074] Further preferred binding materials are amphiphilic
substances, i.e. molecules with a polar and a non-polar part. The
use of graphite is conceivable as well. As far as further binding
materials are concerned, reference is made to WO 98/55229 and to DE
102 32 406.9 whose respective content is incorporated into the
present application by reference.
[0075] Said binding materials can be used either alone or as a
mixture of two or more thereof, or they can be used together with
other materials to be used for enabling or enhancing the binding of
materials containing zeolite, such as oxides of silicon, bor,
phosphor, zirconium, and/or titanium. By way of example, clays are
also to be mentioned.
[0076] In the process of shaping the solid material into a shaped
body, up to approximately 80% by weight of binding materials with
respect to the total mass of the shaped body may be used. It is
preferred to use from approximately 10 to approximately 75% by
weight of binding materials, while using 25% to approximately 45%
is particularly preferred.
[0077] The binding material may be added to the solid material
before, or during, or before and during the step (S) of shaping the
solid material.
[0078] In the process to produce a shaped body, polymers may be
added to create pores of a certain size, a certain volume and/or a
certain size distribution. In the context of the present invention,
polymers are preferred that can be dispersed, emulsified or
suspended in aqueous solvents. Said at least one polymer is
preferably selected from the group of polymer vinyl compounds, such
as polystyrene, polyacrylates, polymethacrylates, polyolefins,
polyamids, and polyesters. These polymers are removed from the
shaped bodies after the process of forming and/or shaping by means
of calcining the shaped body. If polymers are added, the content of
polymer during the production of the shaped body amounts to from
approx. 5 to approx. 90% by weight, preferably from approx. 15 to
approx. 75% by weight, wherein a content ranging from 25 to 55% by
weight is particularly preferred. The amounts given in weight-%
refer to the amount of polymer in the solid material containing
zeolite, respectively.
[0079] Furthermore, it is preferred to add a pasting agent. As far
as the pasting agent is concerned, any substances known from the
prior art to improve the mixing, kneading, or flow properties of
the mass can be used. Preferably, organic hydrophilic polymers are
used, such as cellulose, starch, polyacrylates, polymethacrylates,
polyvinylalcohol, polyvinyl pyrrolidone, polyisobutene,
polytetrahydrofuran. Primarily, these substances enable or improve
the formation of a plastic mass during the process of kneading,
forming, and/or drying by means of bridging the primary particles.
Moreover, these adjuvants enable or enhance the mechanical
stability of the shaped body during the steps of forming or
drying.
[0080] These substances are removed from the shaped body by means
of calcining after the step of shaping. Further adjuvants are
described in EP-A 0 389 041, EP-A 0 200 260, and in WO 95/19222,
the entire contents of which are hereby incorporated by
reference.
[0081] In a preferred embodiment, after having added the binding
material to the solid material containing at least one zeolite, the
organic substance increasing viscosity is added and the mass is
homogenized for 10 to 180 minutes in the kneading apparatus or in
the extruder. The temperature applied to the mass is typically
about 10.degree. C. under the boiling point of the pasting agent.
The pressure is either ambient pressure or slight over-pressure. In
principle, the order of adding additional components to the solid
material and the binder is not believed to be critical. The mass
obtained as described above is kneaded until a plastic mass can be
extruded.
[0082] In the context of the present invention, those methods for
forming a shaped body from a solid material are preferred, in which
the forming can be performed in commercially available extruders.
Preferably, extrudates of a diameter ranging from approx. 1 to
approx. 10 mm are used, particularly preferred are extrudates with
diameters ranging from approx. 2 to approx. 5 mm. Extruders that
can be used in the context of the steps described here are
described, for example, in "Ullmann's Enzyklopaidie der Technischen
Chemie", 4.sup.th Edition, Vol. 2, p. 205 ff. (1972).
[0083] In principle, all methods of shaping and forming that are
known to the expert in the art can be used. Next to extrusion,
other known methods are briquetting, pelleting, pressing,
sintering, or roasting.
[0084] The technique of co-extruding can be employed as well. Here,
two materials are co-extruded simultaneously. Preferably the
aforedescribed active material (solid material according to the
invention) is extruded together with an inert material, i.e. a
material that does not react noticeably with the active material.
Preferably, the matrix of the extruder is designed so that the
active material is extruded as a layer on the inert material.
Therefore, strands result whose core is made of the inert material
and whose outer layer is the active solid material. In a preferred
embodiment, the thickness of the active layer ranges from 1 to 1500
.mu.m, preferably from 5 to 50 .mu.m.
[0085] The use of binding materials or other adjuvants is in any
event optional. The materials to be compacted may be dry or moist
or may prevail as a slurry.
[0086] The step of shaping and/or forming can be performed at
ambient pressure or at a pressure that is elevated with respect to
ambient pressure, for example, in a pressure range from 1 bar to
700 bar. Furthermore, the shaping and/or forming can be performed
at ambient temperature or at a temperature increased with respect
to ambient temperature, e.g., a temperature which is ranging from
20.degree. C. to approx. 300.degree. C. If drying and/or sintering
is part of the shaping and/or forming step, temperatures of up to
1500.degree. C. are conceivable. Furthermore, the step of
compacting and of forming can be performed at ambient atmosphere or
in a controlled atmosphere. Controlled atmospheres include, but are
not limited to, inert gas atmospheres, reducing atmospheres, or
oxidizing atmospheres.
Post-Treatment of the Shaped Body
[0087] After forming and/or shaping (S) the shaped bodies, they are
typically dried at temperatures ranging from approx. 30.degree. C.
to approx. 140.degree. C. for a time interval typically ranging
from 1 h to 20 h. Subsequent to this step, the shaped body is
calcined at temperatures ranging from approx. 400.degree. C. to
approx. 800.degree. C. and for a time interval ranging from approx.
3 h to approx. 10 h. Calcining can be performed at ambient
pressure, preferably in air or in a mixture containing air or under
inert conditions.
[0088] In another step of post-treatment, the extrudates obtained
as described above may be milled and/or crushed. The milling and/or
crushing preferably leads to a granulate with an average particle
diameter ranging from 0.1 to approx. 5 mm. Particle diameters
ranging from approx. 0.5 to 2 mm are particularly preferred.
[0089] Subsequent to the step (S), or subsequent to said step (S)
in conjunction with any step of post-treatments such as (in
particular) drying and calcining, the treatment of bringing the
solid material, in this case a shaped body, in contact with a
material containing water, i.e., the step (W) may be performed.
[0090] If the step (W) is performed at this point, i.e. after the
step (S) or the steps (S) and (C) in conjunction, everything that
has been disclosed before about the specific embodiments of said
step of (W) is valid here as well. In a preferred embodiment, the
shaped body is charged into the reactor that is used for the
desired reaction, typically an epoxidation reaction, and said
shaped body is subjected to the treatment with the composition
containing water in the reactor. Preferably the treatment consists
in exposing and/or bringing in contact of the shaped body with
water steam.
[0091] In addition to the process for producing a solid material
and/or a shaped body as described above, the present invention also
relates to the respective material or shaped body as such.
[0092] In particular, the solid material according to the invention
is obtainable by a sequence of the following steps
[0093] (I) at least partial crystallization of at least one solid
material containing at least one zeolite out of a synthesis
mixture, resulting in mixture (I) containing at least said solid
material and a mother liquor;
[0094] (II) separating and/or concentrating of the solid material
from mixture (I);
[0095] (W) bringing the solid material from step (II) in contact
with a composition containing water;
[0096] (III) agglomerating, or granulating, or agglomerating and
granulating of the solid material from step (W);
[0097] wherein the steps (III) and (W) are optional Step (II) may
additionally include the drying and/or washing of the solid
material, possibly also in several iterations.
[0098] Here, the inventive partial step (I b) is part of the above
mentioned step (I): [0099] (Ia) mixing of at least one hydrolyzable
silicon source with a mineralizing and/or structuring agent and
water; [0100] (Ib) mixing of at least one transition metal oxide
source with an epoxide or a hydrolysate thereof; [0101] (Ic) mixing
of the mixtures from (Ia) and (Ib) so that at least a part of the
hydrolyzable compounds hydrolyzes; [0102] (Id) distilling at least
parts of the alcohol that has been formed as a result of the at
least partial hydrolysation of at least part of the hydrolyzable
compounds; [0103] (Ie) adding water to the bottom of (Id); [0104]
(If) reacting of the synthesis mixture resulting from (Ie) at a
temperature elevated with respect to room temperature.
[0105] Furthermore, the present invention relates to a shaped body
obtained from the solid material described above. The shaped body
is obtained by subjecting the solid material to a step (S) of
shaping, as described in detail above, and (optionally) to a step
(C) of calcining. The sequence of the steps is schematically shown
below: [0106] (I) at least partial crystallization of at least one
solid material containing at least one zeolite out of a synthesis
mixture, as described above in (Ia) to (If), resulting in mixture
(I) containing at least said solid material and a mother liquor;
[0107] (II) separating and/or concentrating of the solid material
in mixture (I); [0108] (III) agglomerating or granulating or
agglomerating and granulating of the solid material from step (W);
[0109] (S) shaping of the solid material from step (II) or
(III)
[0110] Hereby, the following step (W) can optionally be performed
after step (II) or after step (S) or after step (II) and after step
(S): [0111] (W) bringing the shaped body from step (S) in contact
with a composition containing water;
[0112] Finally the present invention relates to the use of the
inventive materials, i.e. the solid material and/or the shaped
bodies as catalysts. The materials obtainable by the inventive
process or the materials obtained by the inventive process are
particularly suited for catalytic reactions involving compounds
with at least one C--C-double bond. Particularly preferred is the
reaction of at least one compound containing at least one
C--C-double bond with at least one hydrogen peroxide. These
reactions are also referred to as epoxidation reactions. As far as
further possible reactions are concerned for which said catalysts
may be employed, reference is made to DE 102 32 406.9 the
respective content of which (in particular pages 27 and 28) is
hereby incorporated by reference.
EXAMPLE C1 (COMPARATIVE EXAMPLE)
[0113] In a four neck flask, 658 g of tetraethoxysilane were mixed
with 20.8 g of tetraethylortho-titanate. While stirring, a solution
of 340 g of tetrapropylamoniumhydroxide (40% by weight, in water)
and 563 g of deionized water were added slowly thereto.
[0114] The solution was stirred at room temperature for 1 hour.
Subsequently, the alcohol formed due to hydrolysis was distilled at
a bottom temperature of 92.degree. C. The bottom (915 g) was filled
with water to 1600 g.
[0115] This batch was reacted in a steel autoclave at 175.degree.
C. and for 24 hours while being stirred. After the mixture had
cooled down, it consisted of a white suspension. Therefrom, the
solid material was filtrated, rinsed with water and dried at
120.degree. C. for 24 hours. Subsequently, said material was
calcined in air twice times for 5 hours, respectively, at a
temperature of 450.degree. C.
[0116] The yield of isolated solid material was 190 g. The content
of Ti of the zeolite of MFI-structure thus obtained was 2.1% by
weight.
[0117] The following test of the catalytic material as described
above had been performed: In a pressure-tight glass reactor, 0.5 g
of said catalyst was mixed with 45 ml of methanol. At a temperature
of 0.degree. C., 20 ml of propylene were dosed in and subsequently,
by means of a pump, 18 g of hydrogen peroxide (30% by weight, in
water; Merck) were metered in. After a reaction time of 5 hours,
the mixture was expanded (pressure released) and the liquid phase
was analyzed by means of gas chromatography. The reaction mixture
contained 8.7% by weight of propylene oxide.
EXAMPLE C2
[0118] The catalyst material as described above was shaped into a
shaped body according to the following procedure: 60 g of the
inventive solid material as described in Example C1 were milled and
mixed with the following substances: 56.5 g of silica sol (Ludox AS
40% by weight SiO.sub.2), a total amount of 32.9 g of a polystyrene
dispersion (43.5 weight % of polymer), 2.7 g of methyl cellulose
(Walocel) and 0.88 g of polyethylene oxide (PEO). 20 g of water
were added to the mass. Said mass was homogenized in a kneading
apparatus.
[0119] However, the materials were not added at the same time.
Specifically, during the process of kneading, the polystyrene
dispersion was added within 5 minutes, and after 10 minutes the
silica sol was added slowly. After 10 further minutes of kneading,
the PEO was added and gobbled for a further 10 minutes.
Subsequently, water was added in portions of 5 ml,
respectively.
[0120] The paste so obtained was formed after a total of 60 minutes
of kneading and at an extrusion pressure of 70 bar via an extruder
having a matrix of 1.5 mm holes. This way the solid material was
alternately formed into strands.
[0121] The shaped body obtained this way was dried for 4 hours at
120.degree. C. (heating ramp of 2 K per minute). Finally, the
shaped body was calcined at 490.degree. C. for 4 hours (heating
ramp 1 K per minute). The atmosphere was air. The yield was 65.24
g. The content of titanium of the shaped body produced this way was
1.4% by weight.
[0122] Said shaped body was subjected to a long term test for
selectivity: 13.5 g of the shaped bodies were loaded into a tube
reactor (1.3 m length). The catalyst was exposed at a pressure of
about 20 bar to a feed of 48 g/hour of methanol, 8.2 g/hour of
hydrogen peroxide (40% by weight) and 4.7 g/hour of propylene (96%
by volume of propylene). Temperatures were regulated between 20 and
40.degree. C.
[0123] The analysis of the product mixture emerging from the
reactor resulted in that after 230 hours, the selectivity for
propylene oxide (with respect to H.sub.2O.sub.2) was 91%. The
formation of oxygen (selectivity with respect to H.sub.2O.sub.2)
was measured to be 2.4% and the unwanted side product methoxy
propanol was formed with a selectivity of 3.3%.
EXAMPLE 1 (CATALYST ACCORDING TO THE PRESENT INVENTION)
[0124] In a four neck flask, 613 g of tetraethoxysilane were mixed
with a solution of 316 g of tetrapropylammoniumhydroxide (40% by
weight, in water) and 523 g of deionized water.
[0125] Separately, 18.1 g of tetrabutylorthotitanate were dissolved
in 109 g of propylene glycol until a clear solution forms.
[0126] Said solution was dosed dropwise into the mixture of
tetraethoxysilane and tetrapropylammoniumhydroxide described above.
The resulting solution was stirred for 30 minutes. Subsequently,
the alcohol formed due to hydrolysis was distilled at a bottom
temperature of 92.degree. C. The bottom (953 g) was filled with
water to 1600 g.
[0127] This batch was reacted in a steel autoclave at 175.degree.
C. and for 24 hours while being stirred. The cooled down mixture
consisted of a white suspension. Therefrom, the solid material was
filtrated, rinsed with water and dried at 120.degree. C. for 24
hours. The yield of dried product was 209.degree. C. Subsequently,
said material was calcined in air twice for 5 hours, respectively,
at a temperature of 450.degree. C. The mass loss due to calcination
was measured to be 13% by weight.
[0128] The content of Ti of the zeolite of MFI-structure thus
obtained was 1.9% by weight.
[0129] The following test of the catalytic material as described
above had been performed: In a pressure-tight glass reactor, 0.5 g
of said catalyst was mixed with 45 ml of methanol. At a temperature
of 0.degree. C., 20 ml of propylene were dosed in and subsequently,
by means of a pump, 18 g of hydrogen peroxide (30% by weight, in
water; Merck) were metered in. After a reaction time of 5 hours,
the mixture was expanded (pressure released) and the liquid phase
was analyzed by means of gas chromatography. The reaction mixture
contained 9.7% by weight of propylene oxide. Despite the lower
content in Ti of the zeolite, the inventive catalyst was shown to
be significantly more active than the respective catalyst from the
comparative example C1.
EXAMPLE 2 (CATALYST ACCORDING TO THE PRESENT INVENTION)
[0130] The catalyst material as described in Example 1 was shaped
into a shaped body according to the following procedure: 60 g of
the inventive solid material as described in Example 1 were milled
and mixed with the following substances: 56.5 g of silica sol
(Ludox AS 40% by weight SiO.sub.2), a total amount of 32.9 g of a
polystyrene dispersion (43.5 weight % of polymer), 2.7 g of methyl
cellulose (Walocel) and 0.88 g of polyethylene oxide (PEO). 20 g of
water were added to the mass. Said mass was homogenized in a
kneading apparatus.
[0131] However, the materials were not added at the same time.
Specifically, during the process of kneading, the polystyrene
dispersion was added within 5 minutes, and after 10 minutes the
silica sol was added slowly. After 10 further minutes of kneading,
the PEO was added and gobbled for a further 10 minutes.
Subsequently, water was added in portions of 5 ml,
respectively.
[0132] The paste so obtained was formed after a total of 60 minutes
of kneading and at a extrusion pressure of 70 bar via an extruder
having a matrix of 1.5 mm holes. This way the solid material was
alternately formed into strands.
[0133] The shaped body contained this way was dried for 4 hours at
120.degree. C. (heating ramp of 2 K per minute). Finally, the
shaped body was calcined at 490.degree. C. for 4 hours (heating
ramp 1 K per minute). The atmosphere was air. The yield was 65.24
g. The content in titanium of the shaped body produced this way was
1.1% by weight.
[0134] Said shaped body was subjected to a long term test for
selectivity: 13.5 g of the shaped bodies were loaded into a tube
reactor (1.3 m length). The catalyst was exposed at a pressure of
about 20 bar to a feed of 48 g/hour of methanol, 8.2 g/hour of
hydrogen peroxide (40% by weight) and 4.7 g/hour of propylene (96%
by volume of propylene). Temperatures were regulated between 20 and
40.degree. C.
[0135] The analysis of the product mixture emerging from the
reactor resulted in that after 215 hours, the selectivity for
propylene oxide (with respect to H.sub.2O.sub.2) was 95.3%. The
formation of oxygen (selectivity with respect to H.sub.2O.sub.2)
was measured to be 0.6% and the unwanted side product methoxy
propanol was formed with a selectivity of 2.4%.
[0136] Therefore, the catalyst of the invention not only showed
increased activity over a catalyst which had not been subjected to
the inventive partial step, but was otherwise obtained the same
way, but also showed improved selectivity.
* * * * *