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
1999-04-14
2001-04-10
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...
C502S103000, C502S104000, C502S113000, C502S115000, C502S118000, C502S128000, C526S090000, C526S123100, C526S124200, C526S124300, C526S125200
Reexamination Certificate
active
06214759
ABSTRACT:
FIELD OF INVENTION
The present disclosure relates to a method for producing a catalyst for use in polymerization of ethylene and copolymerization of ethylene and &agr;-olefin, and more particularly to a method for producing a supported catalyst including a transition metal wherein a titanium compound and a vanadium compound are mixed together in a magnesium-containing carrier of a narrow particle size distribution.
BACKGROUND OF INVENTION
By the co-inventors of the subject invention a method was developed some time ago for producing a supported catalyst for polymerization of ethylene and copolymerization of ethylene and &agr;-olefin, by following the way of coating the catalysts with a transition metal compound, that is, first reacting an organomagnesium compound having the structure of MgPh
2
.nMgCl
2
.mR
2
O (here, n=0.37~0.7; m≧2; R
2
O=ether; Ph=phenyl) with an organic halide, and next coating the thus produced carrier with such transition metal compounds as TiCl
4
, VCl
4
, or VOCl
3
(Japanese Patent Application No. 330675/1995).
The catalyst produced by this publicly known art, particularly the catalyst produced by coating a carrier with VCl
4
marked an advance in part of the polymerization processes by producing polymers of a narrow particle size distribution and an increased bulk density, yet it is found to accompany such problems as yielding polymers of an uncontrolling broad molecular weight distribution and a gradual inactivation of the active substance of vanadium during polymerization.
Meanwhile, a process has been known for producing a catalyst by first reacting magnesium-aluminum-alkyl compound (RMgR
1
-nAlR
3
-mD) and hydrocarbon chloride, and then reacting the thus obtained solid product (carrier) with a titanium or a vanadium halide (German Patent Application No. 3636060: French Patent Application No. 2529207). In this process, (n-Bu)Mg(i-Bu) or (n-Bu)Mg(OCl) dissolved in hydrocarbon is used as an organomagnesium compound, RMgR′, and tert-BuCl is used as hydrocarbon chloride. The main defect of this process is found in the insufficient activity of the produced catalyst.
EP Application EP-A-0, 155,770 is publicly known to teach the production of a catalyst by precipitating a vanadium compound on an elliptical support of magnesium chloride including a composition which contains an electron-donating compound. This catalyst is used in production of ethylene polymers of a wide molecular weight distribution. This catalyst, however, has a defect in that although only a little quantity of vanadium compound is fixed on the support, a relatively large quantity of vanadium compound is required for the purpose. In the performance of washing the catalyst it is generally required to remove the surplus vanadium compound which has not been fixed on the support, and this removal costs much money and is troublesome, because of its toxicity and corrosive properties.
It is publicly known that a polyethylene resin requires a proper molecular weight distribution respectively for different production processes.
Hence, it is required either to adopt a multiple-stage of reactors to produce polyethylenes of different molecular weights from one another from the respective reactors, for control of molecular weight distributions, or alternatively, to develop, by the use of a particular catalyst-activating substance, a catalyst capable of controlling polymers' molecular weight distributions. A multiple-stage of reactors will naturally require a heavy initial investment of capital, and therefore it is preferable to secure a catalyst which can control polymers' molecular weight distributions.
SUMMARY OF INVENTION
In one embodiment, the invention relates to a method for producing a catalyst which will make it possible to produce a polymer of a narrow particle size distribution and an increased bulk density; can control polymer's molecular weight distributions when slurry or gaseous polymerization of ethylene or copolymerization of ethylene and &agr;-olefin is performed; and/or can maintain sufficient activity during polymerization by inhibiting the inactivation of the active substance of vanadium is described.
DETAILED DESCRIPTION OF INVENTION
The method for producing the catalyst is characterized in that the magnesium-containing carrier obtained by reacting an organomagnesium compound, MgPh
2
.nMgCl
2
.mR
2
O (here, n=0.37~0.7; m≧1; R
2
O=ether; Ph=phenyl), with an organic chloride compound, is treated with a titanium compound and a vanadium compound.
The magnesium-containing carrier is produced by reacting, at −20 to 80° C., a solution of the organomagnesium compound with one or more organic chlorides, preferably carbon tetrachloride, in a mole ratio of organic chloride compound/Mg≧0.5. The suspension of the carrier powder containing magnesium, obtained at this stage, has a particular particle size and a narrow particle size distribution.
The organomagnesium compound used when the magnesium-containing carrier is produced is obtained by reacting magnesium in powder form and chlorobenzene in the presence of more than one electron-donating compounds. The electron-donors may include aliphatic ether and cyclic ether. The aliphatic ethers, here, can be represented by a general formula of R
2
OR
3
where the R
2
and R
3
are identical or different alkyl radicals with two to eight carbons, and preferably an aliphatic ether having four to five carbons. The cyclic ethers are those having three or four carbons. The most preferable as electron donors are dibutyl or diisoamylethers.
For the organic chloride compound used in the present invention for producing a magnesium-containing carrier are used such compounds with a general formula CR′
n
Cl
(4−n)
are used (here, n is an integer from 0 to 3), wherein R′ is an alkyl radical with the number of carbons ranging from 1 to 12.
In the method for production of the catalyst in the present invention, in the process of forming the magnesium-containing carrier, a complex of organomagnesium compounds [MgPh
2
.nMgCl
2
.mR
2
O] is used in the state of solution, dissolved in chlorobenzene, ether (R
2
O), or a mixture of chlorobenzene and ether, or a mixture of chlorobenzene and aliphatic or aromatic compounds.
The aforesaid organomagnesium compound in the state of solution is chlorinated with organic chloride in the mole ratio of the organic chloride compound/Mg≧0.5, at −20 to 80° C. The organic chloride diluted in a hydrocarbon solvent can be used in the chlorination of organomagnesium compound. And in this way, a carrier with the magnesium in powder form suspended in the solvent is produced. The carrier obtained in this way possesses a narrow particle size distribution. The particle sizes of the carrier and the catalyst can be adjusted in the range from 5 to 150&mgr;m according to the conditions of the composition of the organomagnesium compounds and of the reaction of the organomagnesium compounds and the organic chloride compound.
The magnesium-containing carrier obtained as above contains, in the main, magnesium dichloride (80~90 wt %), ether (7~15 wt %), and a hydrocarbon complex (1~5 wt %). The carrier may be treated with an organic aluminum compound in the Al/Ti mole ratio of 0.1~2, before treatment with a titanium or a vanadium compound.
The preferable Al/Ti mole ratio is 0.5~1.5, the preferable temperature being 0~80° C. For the organoaluminum compound, the method uses such an organoalkylaluminum having the general formula of AlR′
n
X
(3−n)
or an organic aluminum halogen compound. Here, R′ stands for an alkyl group having 1 to 16, more preferably 2 to 12 carbons, X for chlorine, bromine, and other halogen compound, and n an integer from 0 to 3, or fractions. Such organic aluminum compounds falling within the category include triethylaluminum, triisobutylaluminum, trihexylaluminum, trioctylaluminum, ethylaluminum chloride, methylaluminum chloride, ethylaluminum sesquibromide, isobutylaluminum sesquichloride, dimethylalu
Chang Ho-Sik
Kang Youn-Kyung
Bell Mark L.
Conley & Rose & Tayon P.C.
Di Verdi Michael J.
Samsung General Chemicals Co. Ltd.
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