Catalyst – solid sorbent – or support therefor: product or process – Catalyst or precursor therefor – Plural component system comprising a - group i to iv metal...
Reexamination Certificate
2000-03-13
2001-07-31
Bell, Mark L. (Department: 1755)
Catalyst, solid sorbent, or support therefor: product or process
Catalyst or precursor therefor
Plural component system comprising a - group i to iv metal...
C502S107000, C502S125000, C502S133000, C502S134000, C502S127000
Reexamination Certificate
active
06268306
ABSTRACT:
FIELD OF THE INVENTION
The invention relates to a method for the preparation of a catalyst suitable for the polymerization of an olefins by contacting a magnesium compound with a halogenized Ti-compound.
BACKGROUND INFORMATION
Such a method is known from NL-A-7805523, which discloses, amongst other things, that a catalyst suited to the polymerization of olefins can be obtained by contacting a magnesium compound, which is obtained by reacting during one reaction step metallic magnesium with an organic halide RX, where R is an alkyl, alkenyl, aryl or cycloalkyl group containing from 1 to 20 carbon atoms, and X is a halogen, and an alkoxy group or aryloxy group-containing silane compound with a halogenized Ti-compound.
A drawback of the aforementioned method for the preparation of the catalyst is that the activity of the catalyst obtained is poor.
SUMMARY AND OBJECTS OF THE INVENTION
The aim of the invention is to obtain a method for the preparation of the catalyst in which this drawback does not occur.
The invention is characterised in that:
the magnesium compound is obtained by:
a) contacting metallic magnesium with an aromatic halide RX, where R is an aromatic group containing from 6 to 20 carbon atoms and X is a halogen, whereupon the dissolved reaction product I is separated from the solid residual products and then
b) adding an alkoxy group or aryloxy group-containing silane compound to the obtained reaction product I at a temperature of from −20 to 20° C., whereupon the precipitate is purified to obtain reaction product II,
which subsequently, during a step c, is contacted with TiCl
4
as halogenized Ti-compound and is purified to obtain a catalyst.
In this way a highly active catalyst is obtained.
A further advantage of the catalyst obtained by the process described above is that, when used for the polymerization of propylene, this catalyst yields a polypropylene which is highly isotactic. Furthermore, the polyolefin powder produced with the catalyst of the invention contains few small particles.
From EP-A-0,319,227 a similar method is known for the production of a catalyst suitable for the polymerization of an olefin. According to this patent publication, however, it is necessary to carry out an extra reaction step using a halogen-containing alcohol if a catalyst exhibiting good activity is to be obtained.
DETAILED DESCRIPTION OF THE INVENTION
The first step in the process for the preparation of the catalyst of the invention is carried out by contacting metallic magnesium with an aromatic halide RX.
All forms of metallic magnesium may be used as metallic magnesium, but preferably use is made of finely divided metallic magnesium, for example magnesium powder. To obtain a fast reaction it is preferable to heat the magnesium under nitrogen prior to use. In the aromatic halide RX, R is an aromatic group preferably containing from 6 to 18 carbon atoms and X preferably is chlorine or bromine. Chlorobenzene, bromobenzene and iodinebenzene can be mentioned as examples.
Preferably chlorobenzene is used as the aromatic halide RX.
The magnesium and the aromatic halide RX are preferably brought into contact with one another in the presence of an inert dispersant and an ether. Examples of dispersants are: aliphatic, alicyclic or aromatic solvents containing 4-10 carbon atoms. Examples of ethers are: diethyl ether, diisopropyl ether, dibutyl ether, diisobutyl ether, diisoamyl ether, diallyl ether, tetrahydrofuran (THF) and anisole. It is preferred for dibutyl ether and/or diisoamyl ether to be used. Preferably, chlorobenzene is used as dispersant. Thus, the chlorobenzene serves as dispersant as well as aromatic halide RX.
The aromatic halide/ether ratio is important with respect to obtaining an active catalyst. The chlorobenzene/dibutyl ether volume ratio may for example vary between 75:25 and 35:65.
When the chlorobenzene/dibutyl ether ratio decreases, the bulk density of the polyolefine powder prepared with the aid of the catalyst becomes lower and when the chlorobenzene/dibutyl ether ratio increases, the amount of the dissolved reaction product I becomes lower. Consequently, the best results are obtained when the chlorobenzene/dibutyl ether volume ratio is between 70:30 and 50:50.
Small amounts of iodine and/or alkyl halides can be added to cause the reaction between the metallic magnesium and the aromatic halide RX to proceed at a higher rate. Examples of alkyl halides are butyl chloride, butyl bromide and 1,2-dibromoethane. The reaction temperature for step a normally is between 20 and 150° C.; the reaction time between 0.5 and 20 hours.
After the reaction is completed, the dissolved reaction product I is separated from the solid residual products.
During step b of the reaction, the dissolved reaction product I, obtained on carrying out step a of the reaction, is brought into contact with an alkoxy group or aryloxy group-containing silane compound. This is accomplished by adding the alkoxy group or aryloxy group-containing silane compound to the dissolved reaction product I at a temperature of from −20 to 20° C. Preferably at a temperature of from −5 to 5° C.
Preferably, reaction product I is contacted with the alkoxy group or aryloxy group-containing silane compound in the presence of an inert hydrocarbon solvent such as the solvents mentioned as dispersant in the discussion of step a. Preferably, step b is carried out with stirring. The Si/Mg molar ratio during step b may vary from 0.2 to 20. Preferably, the Si/Mg molar ratio is from 0.4 to 1.0. The product from step b is rinsed with an inert hydrocarbon solvent and then used for the preparation of the catalyst.
The following examples of alkoxy group or aryloxy group-containing silane compounds may be mentioned: tetramethoxysilane, tetraethoxysilane, tetrabutoxysilane, tetraisobutoxysilane, tetraphenoxysilane, tetra(p-methylphenoxy)silane, tetrabenzyloxysilane, methyltrimethoxysilane, methyltriethoxysilane, methyltributoxysilane, methyltriphenoxysilane, methyltriphenoxysilane, ethyltriethoxysilane, ethyltriisobutoxysilane, ethyltriphenoxysilane, butyltrimethoxysilane, butyltriethoxysilane, butyltributoxysilane, butyltriphenoxysilane, isobutyltriisobutoxysilane, vinyl triethyoxysilane, allyltrimethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, benzyltriphenoxysilane, methyltriallyloxysilane, dimethyldimethoxysilane, dimethyldiethoxysilane, dimethyldiisopropyloxysilane, dimethyldibutoxysilane, dimethyldihexyloxysilane, dimethyldiphenoxysilane, diethyldiethoxysilane, diethyldiisobutoxysilane, diethyldiphenoxysilane, dibutyldiisopropyloxysilane, dibutyldibutoxysilane, dibutyldiphenoxysilane, diisobutyldiethoxysiane, diisobutyldiisobutoxysilane, diphenyldimethoxysilane, diphenyldiethoxysilane, diphenyldibutoxysilane, dibenzyldiethoxysilane, divinyl diphenoxysilane, diallyldipropoxysilane, diphenyldiallyloxysilane, methylphenyldimethoxysilane and chlorophenyldiethyoxysilane.
Preferably use is made of tetraethoxysilane. The preparation of the catalyst is carried out by contacting, during a step c, the purified reaction product from step b with TiCl
4
.
Preferably an electron donor is also present during step c. Examples of electron donors are carboxylic acids, carboxylic anhydrides, esters of carboxylic acids, halide carboxylic acids, alcohols, ethers, ketones, amines, amides, nitriles, aldehydes, alcoholates, sulphonamides, thioethers, thioesters, organic silicon compounds and organic compounds containing a heteroatom, such as nitrogen, oxygen and phosphorus. Examples of carboxylic acids are formic acid, acetic acid, propionic acid, butyric acid, isobutanoic acid, acrylic acid, methacrylic acid, maleic acid, fumaric acid, tartaric acid, cyclohexanoic monocarboxylic acid, cis-1,2-cyclohexanoic dicarboxylic acid, phenylcarboxylic acid, toluenecarboxylic acid, naphthalene carboxylic acid, phthalic acid, isophthalic acid, terephthalic acid and trimellitic acid.
Anhydrides of the aforementioned carboxylic acids can be mentioned as examples of carboxylic anhydrides, such as acetic acid anhydride, butyric acid
Bukatov Gennadii D.
Sergeev Sergei A.
Zakharov Vladimir A
Bell Mark L.
DSM N.V.
Pasterczyk J.
Pillsbury & Winthrop LLP
LandOfFree
Method for preparing a catalyst suitable for polymerizing an... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Method for preparing a catalyst suitable for polymerizing an..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method for preparing a catalyst suitable for polymerizing an... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2497934