Title of Invention

PROCESS FOR THE PRODUCTION OF A DISPERSION CONTAINING PYROGENIC SILICON TITANIUM MIXED OXIDE POWDER

Abstract Process for the production of a dispersion containing pyrogenic silicon titanium mixed oxide powder with a silicon dioxide content of 75 to 99.99 wt.% and a titanium dioxide content of 0.01 to 25 wt.-%, water and a basic, quaternary ammonium compound, the particles of the silicon-titanium mixed oxide powders in the dispersion having a mean aggregate diameter of 200 nm at most, comprising the steps: water, which, in the event that the silicon-titanium mixed oxide powder incorporated later leads to a pH value of the aqueous phase of <2 or >4, is adjusted to pH values of 2 to 4 by addition of acids or bases, is circulated from a holding tank through a rotor/stator machine, and - via a filling device, silicon-titanium mixed oxide powder is continuously or discontinuously introduced into the shear zone between the grooves of the rotor teeth and the stator groove, with the rotor/stator machine running, in a quantity such that a predispersion with a solids content of 20 to 40 wt.% results, and after all the silicon-titanium mixed oxide powder has been added, the filling device is closed, and shearing continued such that the shear rate lies in the range between 10000 to 40000 sec-1, and next, while maintaining the dispersing conditions, a basic, quaternary ammonium compound and optionally water, before the addition of the ammonium compound, are added.
Full Text silicon-titanium mixed oxide-containing dispersion for the
production of titanium-containing zeolites
The invention relates to a silicon-titanium mixed oxide
powder-containing dispersion for the production of
titanium-containing zeolites.
From EP-A-814058, the use of silicon-titanium mixed oxide
powders for the production of titanium-containing zeolites
is known. Titanium-containing zeolites are efficient
catalysts for the oxidation of olefins with hydrogen
peroxide. They are obtained by hydrothermal synthesis,
starting from silicon-titanium mixed oxide powders in the
presence of a template. In EP-A-814058, it is disclosed
that pyrogenic silicon-titanium mixed oxides with a silicon
dioxide content of 75 and 99.9 wt.-% can be used for this.
Particularly advantageous is a composition which contains
from 90 to 99.5 wt.-% silicon dioxide and 0.5 to 5 wt.%
titanium dioxide. As templates, amines, ammonium compounds
or alkali (alkaline earth) metal hydroxides can be used.
A disadvantage of the process disclosed in EP-A-814058 is
that it leads to products whose catalytic activity is often
not reproducible and is often not adequate.
The purpose of the present invention was therefore to
provide a silicon-titanium mixed oxide in a form which
makes it possible to produce titanium-containing zeolites
of high catalytic activity.
The object of the invention is a dispersion containing
pyrogenic silicon-titanium mixed oxide powders with a
silicon dioxide content of 75 to 99.99 wt.% and a titanium
dioxide content of 0.01 to 25 wt.%, water and a basic,
quaternary ammonium compound, wherein the mean aggregate
diameter of the particles of the silicon-titanium mixed
oxide powder in the dispersion is 200 nm at most.

It was found that on use of this dispersion, which contains
particles of this fineness, the reaction time which is
needed for the production of titanium-containing zeolites
is markedly reduced. Preferably, the mean aggregate
diameter is less than 100 nm.
Pyrogenic should be understood to refer to metal mixed
oxide particles obtained by flame oxidation and/or flame
hydrolysis. During this, oxidisable and/or hydrolysable
starting materials are oxidised or hydrolysed as a rule in
a hydrogen-oxygen flame. The metal mixed oxide particles
according to the invention are as pore-free as possible and
have free hydroxyl groups on the surface. They are present
in the form of aggregated primary particles.
The BET surface area of the pyrogenic silicon-titanium
mixed oxide powders is not limited. It has however been
found advantageous if the BET surface area lies in a range
from 20 to 400 m2/g and in particular from 50 to 300 m2/g.
The use of a silicon-titanium mixed oxide powder of high
BET surface area in combination with a small mean aggregate
diameter in the dispersion is particularly advantageous for
the production of titanium-containing zeolites.
It has further been found advantageous if the dispersion
contains a pyrogenic silicon-titanium mixed oxide powder,
wherein the proportions of Na, K, Fe, Co, Ni, Al, Ca and Zn
are each less than 50 ppm, in particular less than 25 ppm.
Such a dispersion leads to titanium-containing zeolites
with high catalytic activity.
The dispersion according to the invention also contains a
basic, quaternary ammonium compound. These are preferably
tetraalkylammonium hydroxides such as for example
tetraethylammonium hydroxide, tetra-n-propylammonium
hydroxide and/or tetra-n-butylammonium hydroxide. Basic,
quaternary ammonium compounds serve as templates which
determine the crystal structure through incorporation into

the crystal lattice. Tetra-n-propylammonium hydroxide is
preferably used for the production of titanium silicalite-1
(MFI structure), tetra-n-butylammonium hydroxide for the
production of titanium silicalite-2 (MEL structure) and
tetraethylammonium hydroxide for the production of titanium
β-zeolites (BEA crystal structure) .
The ratio water / silicon-titanium mixed oxide powder is
preferably 10 oxide The content of quaternary, basic ammonium compound in the
dispersion according to the invention is not limited. If
the dispersion is to be stored for a prolonged period, it
can be advantageous to add to it only a part of the
quantity of the dispersion necessary for the production of
a titanium-containing zeolite. Preferably, the quaternary,
basic ammonium compound can be added in a quantity such
that a pH value of 9 to 11, in particular 9.5 to 10.5,
results. In this pH range, the dispersion displays good
stability.
If for example the dispersion is to be used directly after
its production for the production of a titanium-containing
zeolite, the dispersion can already contain the whole
quantity of quaternary, basic ammonium compound. Preferably
then 0.12 mixed oxide silicon-titanium mixed oxide preferred.
A further object of the invention is a process for the
production of the dispersion comprising the steps:
- water, which, in the event that silicon-titanium mixed
oxide powder incorporated later leads to a pH value of
the aqueous phase of 4, is adjusted to pH values

micropellets, spheres, tablets, solid cylinders, hollow
cylinders or honeycombs by known methods for the shaping of
catalysts in powder form, such as for example pelleting,
spray-drying, spray pelleting or extrusion.
The titanium-containing zeolite according to the invention
can be used as a catalyst in oxidation reactions with
hydrogen peroxide. In particular, it can be used as a
catalyst in the epoxidation of olefins by means of aqueous
hydrogen peroxide in a solvent miscible with water.
Examples
Example 1: Production of a silicon-titanium mixed oxide
powder
5.15 kg/hr of silicon tetrachloride and 0.15 kg/hr of
titanium tetrachloride are vaporised. The vapours are
transferred into a mixing chamber by means of 15 Nm3/hr of
nitrogen as carrier gas. Separately from this, 2 Nm3/hr of
hydrogen and 8 Nm3/hr of primary air are introduced into
the mixing chamber. In a central pipe, the reaction mixture
is fed into a burner and ignited. Here the flame burns in a
water-cooled flame tube. In addition, 15 Nm3/hr of
secondary air is introduced into the reaction space. The
powder produced is separated in a filter connected
downstream and then treated with a counter-current of
hydrogen at 520°C.
The powder displays the following values:
Silicon dioxide 96.6 wt.%
Titanium dioxide 3.4 wt.%
BET surface area 80 m2/g

of 2 to 4 by addition of acids or bases, is circulated
from a holding tank through a rotor/stator machine, and
- via a filling device, silicon-titanium mixed oxide powder
is introduced continuously or discontinuously into the
shear zone between the grooves of the rotor teeth and the
stator grooves, with the rotor/stator machine running, in
a quantity such that a predispersion with a solids
content of 20 to 40 wt.-% results, and
- after all the silicon-titanium mixed oxide powder has
been added, the filling device is closed, and shearing
continued such that the shear rate lies in the range
between 10000 to 40000 sec-1, and
- then, while maintaining the dispersion conditions, a
basic, quaternary ammonium compound is added, and
optionally water, before the addition of the ammonium
compound.
A further object of the invention is a process for the
production of a titanium-containing zeolite, wherein the
dispersion according to the invention, optionally with
further addition of the basic, quaternary ammonium
compound, is processed at a temperature of 150 to 220°C for
a period of less than 12 hours. The crystals obtained are
separated by filtration, centrifugation or decantation and
washed with a suitable washing liquid, preferably water.
The crystals are then dried as required, and calcined at a
temperature between 400°C and 1000°C, preferably between
500°C and 750°C, in order to remove the template.
A further object of the invention is a titanium-containing
zeolite, which is obtainable by the process according to
the invention.
The titanium-containing zeolite is obtained in powder form.
For its use as an oxidation catalyst, as required it is
converted into a form suitable for the use, e.g. into

Example 2: Production of a Dispersion (according to
invention)
32.5 kg of deionised water are first placed in a 100 1
stainless steel batch vessel. Next, 17.5 kg of the silicon-
titanium mixed oxide powder from Example 5 are inducted
under shear conditions using the suction tube of the Ystral
Conti-TDS 4 (Stator groove: 6 mm ring and 1 mm ring,
rotor/stator gap ca. 1 mm). After completion of the
induction, the inlet nozzle is closed and the 35 weight
percent predispersion is sheared for a further 10 mins at
3000 rpm. Undesired warming of the dispersion due to the
high energy input is counteracted with a heat exchanger and
the temperature rise limited to max. 40 °C. Owing to the
acidic nature of the pyrogenically produced silicon-
titanium mixed oxide powder, the pH value of the dispersion
is ca. 3.6.
Next, 28.6 kg of deionised water are added, and a pH value
of 10.0 is rapidly established under intensive shearing and
thorough mixing with 1.0 kg of tetra-n-propylammonium
hydroxide solution (40 wt.-% in water).
The dispersion displays the following values:
Water/silicon-titanium mixed oxide 11.7
Mean aggregate diameter 94 nm (determined on Horiba LA 910)
Example 3: Production of a Dispersion (Comparison) •
1 g of tetra-n-propylammonium hydroxide solution (40 wt.-%
in water) are added to 17.5 g of the silicon-titanium mixed
oxide powder from Example 1 in 61.1 ml of water under
dispersing conditions by means of a dissolver, and
dispersed for 30 mins. The dispersion obtained has a
markedly higher viscosity in comparison to Example 3.
Coarse aggregates can clearly be discerned as well as finer
ones.
The dispersion displays the following values:
Water/silicon-titanium mixed oxide 13.2

Tetrapropylammonium hydroxide/silicon-titanium mixed oxide
0.14
Mean aggregate diameter 256 nm
Example 4: Production of a titanium-containing zeolite
(according to invention)
505 g of the dispersion from Example 2 are first placed in
a polyethylene beaker, 46.7 g of deionised water and 130.6
g of a tetra-n-propylammonium hydroxide solution (40 wt.-%
in water) are added and firstly aged for four hours at 80°C
with stirring and then crystallised for 10 hours at 180°C
in an autoclave. The solid obtained is separated from the
mother liquor by centrifugation, washed with 3 x 250 ml
portions of deionised water, dried at 90°C and calcined in
an atmosphere of air for four hours at 550°C.
The Xray diffraction diagram of the crystals obtained from
Example 4 shows the diffraction pattern typical for the MFI
structure, and the IR spectrum the characteristic bands at
960 cm-1. The UV/visible light spectrum shows that the
sample is free from titanium dioxide and titanates.
Example 5 is performed analogously to Example 4, but with
the use of the dispersion from Example 3.
In contrast to Example 4, Example 5 yields markedly more
coarse zeolite aggregates. In the catalytic epoxidation of
propylene, the product from Example 4 displays a higher
activity than that from Example 5.

WE CLAIM:
4 • Process for the production of a dispersion containing pyrogenic silicon titanium mixed oxide
powder with a silicon dioxide content of 75 to 99.99 wt.% and a titanium dioxide content of
0.01 to 25 wt.-%, water and a basic, quaternary ammonium compound, the particles of the
silicon-titanium mixed oxide powders in the dispersion having a mean aggregate diameter of
200 nm at most, comprising the steps:
water, which, in the event that the silicon-titanium mixed oxide powder
incorporated later leads to a pH value of the aqueous phase of 4, is adjusted
to pH values of 2 to 4 by addition of acids or bases, is circulated from a holding
tank through a rotor/stator machine, and
via a filling device, silicon-titanium mixed oxide powder is continuously or
discontinuously introduced into the shear zone between the grooves of the rotor
teeth and the stator groove, with the rotor/stator machine running, in a quantity such
that a predispersion with a solids content of 20 to 40 wt.% results, and
after all the silicon-titanium mixed oxide powder has been added, the filling device
is closed, and shearing continued such that the shear rate lies in the range between
10000 to 40000 sec-1, and

next, while maintaining the dispersing conditions, a basic, quaternary ammonium
compound and optionally water, before the addition of the ammonium compound,
are added.


ABSTRACT

Title: PROCESS FOR THE PRODUCTION OF A DISPERSION CONTAINING
PYROGENIC SILICON TITAIUM MIXED OXIDE POWDER
Process for the production of a dispersion containing pyrogenic silicon titanium mixed oxide
powder with a silicon dioxide content of 75 to 99.99 wt.% and a titanium dioxide content of
0.01 to 25 wt.-%, water and a basic, quaternary ammonium compound, the particles of the
silicon-titanium mixed oxide powders in the dispersion having a mean aggregate diameter of
200 nm at most, comprising the steps:
water, which, in the event that the silicon-titanium mixed oxide powder
incorporated later leads to a pH value of the aqueous phase of 4, is adjusted
to pH values of 2 to 4 by addition of acids or bases, is circulated from a holding
tank through a rotor/stator machine, and - via a filling device, silicon-titanium mixed oxide powder is continuously or
discontinuously introduced into the shear zone between the grooves of the rotor
teeth and the stator groove, with the rotor/stator machine running, in a quantity such
that a predispersion with a solids content of 20 to 40 wt.% results, and
after all the silicon-titanium mixed oxide powder has been added, the filling device
is closed, and shearing continued such that the shear rate lies in the range between
10000 to 40000 sec-1, and
next, while maintaining the dispersing conditions, a basic, quaternary ammonium
compound and optionally water, before the addition of the ammonium compound,
are added.

Documents:

4190-KOLNP-2008-(10-04-2012)-ABSTRACT.pdf

4190-KOLNP-2008-(10-04-2012)-AMANDED CLAIMS.pdf

4190-KOLNP-2008-(10-04-2012)-CORRESPONDENCE.pdf

4190-KOLNP-2008-(10-04-2012)-DESCRIPTION (COMPLETE).pdf

4190-KOLNP-2008-(10-04-2012)-FORM-1.pdf

4190-KOLNP-2008-(10-04-2012)-FORM-2.pdf

4190-KOLNP-2008-(10-04-2012)-OTHERS.pdf

4190-KOLNP-2008-(17-02-2012)-EXAMINATION REPORT REPLY RECIEVED.PDF

4190-KOLNP-2008-(17-02-2012)-FORM-3.pdf

4190-KOLNP-2008-(24-05-2012)-PETITION UNDER RULE 137.pdf

4190-KOLNP-2008-(28-08-2012)CORRESPONDENCE.pdf

4190-kolnp-2008-abstract.pdf

4190-kolnp-2008-claims.pdf

4190-KOLNP-2008-CORRESPONDENCE 1.3.pdf

4190-KOLNP-2008-CORRESPONDENCE-1.1.pdf

4190-kolnp-2008-correspondence.pdf

4190-kolnp-2008-description (complete).pdf

4190-KOLNP-2008-EXAMINATION REPORT.pdf

4190-kolnp-2008-form 1.pdf

4190-KOLNP-2008-FORM 18 1.1.pdf

4190-kolnp-2008-form 18.pdf

4190-kolnp-2008-form 2.pdf

4190-KOLNP-2008-FORM 3 1.1.pdf

4190-kolnp-2008-form 3.pdf

4190-KOLNP-2008-FORM 5 1.1.pdf

4190-kolnp-2008-form 5.pdf

4190-KOLNP-2008-GPA 1.1.pdf

4190-kolnp-2008-gpa.pdf

4190-KOLNP-2008-GRANTED-ABSTRACT.pdf

4190-KOLNP-2008-GRANTED-CLAIMS.pdf

4190-KOLNP-2008-GRANTED-DESCRIPTION (COMPLETE).pdf

4190-KOLNP-2008-GRANTED-FORM 1.pdf

4190-KOLNP-2008-GRANTED-FORM 2.pdf

4190-KOLNP-2008-GRANTED-SPECIFICATION.pdf

4190-kolnp-2008-international publication.pdf

4190-KOLNP-2008-INTERNATIONAL SEARCH REPORT 1.1.pdf

4190-kolnp-2008-international search report.pdf

4190-KOLNP-2008-OTHERS 1.1.pdf

4190-KOLNP-2008-OTHERS.pdf

4190-KOLNP-2008-PCT PRIORITY DOCUMENT NOTIFICATION 1.1.pdf

4190-kolnp-2008-pct priority document notification.pdf

4190-kolnp-2008-pct request form.pdf

4190-KOLNP-2008-REPLY TO EXAMINATION REPORT.pdf

4190-kolnp-2008-specification.pdf

4190-KOLNP-2008-TRANSLATED COPY OF PRIORITY DOCUMENT 1.1.pdf

4190-kolnp-2008-translated copy of priority document.pdf


Patent Number 253653
Indian Patent Application Number 4190/KOLNP/2008
PG Journal Number 32/2012
Publication Date 10-Aug-2012
Grant Date 08-Aug-2012
Date of Filing 15-Oct-2008
Name of Patentee EVONIK DEGUSSA GMBH.
Applicant Address RELLINGHAUSER STRASSE 1-11, 45128 ESSEN
Inventors:
# Inventor's Name Inventor's Address
1 KAI SCHUMACHER BAHNSTR. 30, 65719 HOFHEIM
2 WOLFGANG LORTZ FELDSTR. 9, 63607 WACHTERSBACH
PCT International Classification Number C01B 33/14
PCT International Application Number PCT/EP2007/052278
PCT International Filing date 2007-03-12
PCT Conventions:
# PCT Application Number Date of Convention Priority Country
1 10 2006 017 700.2 2006-04-15 Germany