Catalyst – solid sorbent – or support therefor: product or process – Catalyst or precursor therefor – Organic compound containing
Reexamination Certificate
2000-04-19
2002-03-19
Bell, Mark L. (Department: 1755)
Catalyst, solid sorbent, or support therefor: product or process
Catalyst or precursor therefor
Organic compound containing
C502S158000, C502S152000, C502S109000, C526S159000, C526S194000, C526S226000, C526S279000
Reexamination Certificate
active
06358876
ABSTRACT:
TECHNOLOGICAL FIELD
The invention relates to particles comprising organopolysiloxane gel microparticles and organoaluminum compounds immobilized thereon, to their preparation, and to their use as cocatalysts together with metal compounds from sub-groups 4, 5, 6 and 8-10 of the Periodic Table, for the oligomerization, cyclization or polymerization of olefins.
DESCRIPTION OF THE RELATED ART
Aluminoxanes are obtained by controlled hydrolysis of organoaluminum compounds. For example, oligomeric methylaluminoxane is prepared by controlled hydrolysis of trimethylaluminum using water.
Organoaluminoxanes have a broad range of application as cocatalysts in metalcatalyzed olefin oligomerization, cyclization or polymerization using metal compounds from sub-groups 4, 5, 6 and 8-10 of the Periodic Table, where the added organoaluminoxane serves as activator for the catalytically active metal compound. In U.S. Pat. No. 5,206,401, for example, methylaluminoxanes are added to catalytically active metallocene compounds of metals from sub-group 4 of the Periodic Table as activators for olefin polymerization.
When carrying out metal-catalyzed olefin polymerization activated by organoaluminoxane, for example using metallocene or semisandwich catalysts, a recurring problem is that of reactor fouling, i.e. during the reaction, the reactor walls become coated with the polyolefin formed. Temperature control during the reaction is no longer possible. The deposits ultimately result in the reactor blocking up completely. In large-scale industrial production, this results in plant shutdowns and thus high costs. Another problem in the preparation of polyolefins is the morphology of the product obtained. Without further additives, a finely pulverulent product is obtained. For further industrial processing, however, the polymer should be produced in larger particle sizes, preferably having a spherical shape with a mean sphere diameter of 0.1 to 3 mm.
Reactor fouling can be suppressed by carrying out the immobilization of the active catalyst center by applying the cocatalyst, such as methylaluminoxane (MAO) or ethylaluminoxane, to silica gel. This is described, for example, in U.S. Pat. No. 4,925,821. The heterogenization of the cocatalyst means that the actual polymerization-active cationic reaction center is quasi-heterogenized via an ionic interaction with the anionic organoaluminoxane.
The heterogenization is carried out in a multiphase reaction; wetting problems, long reaction times, incomplete reaction and difficult reaction control and end-point determination of the reaction must be accepted. Furthermore, the heterogenization of the cocatalyst causes a significant reduction in the catalytic activity. Likewise, the cocatalyst in metalcatalyzed reactions of olefins must be added in a large excess, namely in a molar ratio of from 1:1000 to 1:20,000. The ratio between catalytically active metal and cocatalyst is rather random and cannot be set precisely.
The object was to provide organoaluminum compound-carrying particles which, when used as cocatalysts together with metal compounds, have high catalytic activity in the polymerization, oligomerization or cyclization of olefins, where it should be possible to control precisely the amount of organoaluminum compound-carrying particles employed, i.e. the ratio between the active metal center and aluminum.
SUMMARY OF THE INVENTION
The invention relates to p articles comprising organopolysiloxane gel microparticles having a diameter of from 5 to 200 nm and organoaluminum compounds immobilized thereon.
The novel particles are, after their preparation, at least finely suspendable or soluble in all inert organic solvents. The size of the particles is from 10 nm for individual particles up to 500 microns for agglomerates.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT(S)
The particles are preferably composed of [organosiloxane gel microparticle content]
a
[aluminoxane content]
b
[monomeric and oligomeric organoaluminum compound]
c
, where
a is from 1 to 99.9% by weight
b is from 1 to 99% by weight and
c is from 0 to 10% by weight, with the proviso that the individual components add up to 100% by weight.
a is preferably at most 50% by weight, in particular at most 20% by weight. b is preferably at least 10% by weight, in particular at least 50% by weight. b is preferably at most 90% by weight. c is preferably at least 0.1% by weight, in particular at least 0.5% by weight, and particularly preferably at least 2% by weight. c is preferably at most 5% by weight.
The organopolysiloxane content of the particles preferably consists of
from 0.5 to 80% by weight of units of the general formula
[R
1
d
R
2
3-d
SiO
1/2
] (1),
from 0 to 99.0% by weight of units of the general formula
[R
1
e
R
2
2-e
SiO
2/2
] (2),
from 0 to 99.5% by weight of units of the general formula
[R
1
f
R
2
1-f
SiO
3/2
] (3) and
from 0 to 99.5% by weight of units of the general formula
[SiO
4/2
] (4),
where
R
1
are identical or different monovalent, Si—O—C-bonded C
1
- to C
30
-hydrocarbon radicals optionally carrying functional groups, or hydrogen,
R
2
are identical or different monovalent, SiC-bonded C
1
- to C
30
-hydrocarbon radicals optionally carrying functional groups and optionally also interrupted by the heteroatoms O, N or S, or hydrogen,
d has the value 0, 1, 2 or 3
e has the value 0, 1 or 2, and
f has the value 0 or 1.
Examples of unsubstituted radicals R
1
are alkyl radicals, such as the methyl, ethyl and propyl radicals; cycloalkyl radicals, such as cyclohexane radical; and aryl radicals, such as the phenyl radical.
Examples of radicals R
1
carrying functional groups are halogenated hydrocarbon radicals, preferably haloalkyl radicals, such as the 3,3,3-chloromethyl, 3-chloropropyl, 3-bromopropyl, 3,3,3-trifluoropropyl and 5,5,5,4,4,3,3-heptafluoropentyl radicals.
The radical R
1
is in particular an unsubstituted C
1
- to C
6
-alkyl radical, a phenyl radical or hydrogen, in particular the methyl radical.
Examples and preferred examples of unsubstituted radicals R
2
are the radicals indicated above for R
1
.
Examples of hydrocarbon radicals R
2
carrying functional groups are halogenated hydrocarbon radicals, namely haloalkyl radicals, such as the 3,3,3-chloromethyl, 3-chloropropyl, 3-bromopropyl, 3,3,3-trifluoropropyl and 5,5,5,4,4,3,3-heptafluoropentyl radicals, and haloaryl radicals, such as the o-, m- and p-chlorophenyl radicals; hydrocarbon radicals carrying primary, secondary and tertiary amines, for example aminoalkyl radicals, such as the 2-aminoethyl, 3-aminopropyl, N-(2-aminoethyl)-3-aminopropyl, N-(2-aminoethyl)-3-amino-(2-methyl)propyl and pyrimidinyl radicals, aminoaryl radicals, such as the aminophenyl radical; quaternary ammonium radicals; hydrocarbon radicals carrying mercapto groups, such as the 2-mercaptoethyl and 3-mercaptopropyl radicals; cyanoalkyl radicals, such as the 2-cyanoethyl and 3-cyanopropyl radicals; hydrocarbon radicals carrying acrylyl groups, for example acryloxyalkyl radicals, such as 3-acryloxypropyl and 3-methacryloxypropyl radicals; hydrocarbon radicals carrying hydroxyl groups, for example hydroxyalkyl radicals, such as the hydroxypropyl radical; hydrocarbon radicals carrying phosphonic acid, phosphonato and sulfonato groups; saturated and unsaturated, linear and cyclic hydrocarbon radicals interrupted by the heteroatoms O, N or S, such as the furanyl, pyridyl and thiophenyl radicals.
Radical R
2
is preferably an unsubstituted C
1
- to C
6
-alkyl radical or the phenyl radical, in particular the methyl, ethyl or propyl radical.
Further main-group elements, such as boron and aluminum, can be attached to R
1
via an Si—O—C bond or to a further oxygen atom of the hydrocarbon radicals R
1
and R
2
carrying functional groups.
The aluminoxane content of the particles preferably consists of
from 0.5 to 99% by weight of units of the general formula
[X
i
R
4
g
R
3
2-g
AlO
1/2
] (5),
from 0 to 99% by weight of units
Alt Helmut
Baumann Frank
Köppl Alexander
Weis Johann
Bell Mark L.
Brooks & Kushman P.C.
Pasterczyk J.
Wacker-Chemie GmbH
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