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
1998-12-23
2001-03-27
Wu, David W. (Department: 1713)
Catalyst, solid sorbent, or support therefor: product or process
Catalyst or precursor therefor
Plural component system comprising a - group i to iv metal...
C502S125000, C502S129000, C502S133000, C502S150000, C502S107000, C526S138000
Reexamination Certificate
active
06207607
ABSTRACT:
This application is the national phase under 35 U.S.C. §371 of prior PCT International Application No. PCT/FI97/00191 which has an International filing date of Mar. 26, 1997 which designated the United States of America, the entire contents of which are hereby incorporated by reference.
The present invention relates to compositions containing magnesium, titanium, halogen and a carboxylic acid ester. The invention also relates to such compositions prepared by bringing into contact with each other at a certain temperature and reacting the complex MgX
1
2
.nR
1
OH, where X
1
is a halogen, R
1
is a C
1
-C
20
alkyl and n is in the range 2.0-6.4, a titanium tetrahalide, TiX
2
4
, where X
2
is a halogen, and a carboxylic acid ester.
The invention further relates to the above-mentioned type of method for preparation of a composition containing magnesium, titanium, halogen and a carboxylic acid ester. Finally, the invention relates to a method for polymerisation of &agr;-olefins by bringing into contact with each other and reacting a procatalyst, which is an above-mentioned type of composition containing magnesium, titanium, halogen and a carboxylic acid ester or which contains such a composition, a cocatalyst, which is an organometallic compound of a metal belonging to one of groups 1, 2 or 13 of the periodic system, preferably an external donor with at least one ligand atom capable of donating an electron, and one or more &agr;-olefins.
Polymerisation catalysts, especially Ziegler-Natta type of polymerisation catalysts, nowadays typically comprise an inert solid carrier upon which the actual active catalyst component or a mixture or complex of catalytic compounds is layered. The chemical composition, surface structure, morphology, particle size and particle size distribution of such a heterogeneous catalytic system are very important for the activity of the catalyst and for the properties of the polymer obtained by means of the catalyst. As it is, a very active catalyst can yield a polymer and, in particular, a poly-&agr;-olefin that is so pure as to require no removal of catalyst residues.
The above-mentioned type of heterogeneous catalytic systems nowadays often comprise a magnesium-based carrier treated with a transition-metal compound, such as a titanium halide, and often even with an electron-donating compound. It is also known that the carrier can be furnished with a favourable chemical composition, surface structure, morphology, particle size and particle size distribution by allowing it to crystallise as a complex of one of its crystal solvents.
In a method according to EP 65700 and U.S. Pat. No. 4,421,674, a titanium halide is made to react with a magnesium chloride catalyst carrier in microsphere form whereafter the particles of reaction product are recovered by physical means and mixed with an organometallic cocatalytic compound.
FI patent application 862459 presents a method for carrier preparation where a carrier complex consisting of a carrier substance, such as magnesium chloride, MgCl
2
, and a crystal solvent, such as ethanol, C
2
H
5
OH, is melted into a clear liquid. When this liquid is conducted through a nozzle and an atomising chamber into a crystallisation chamber cooled with cold nitrogen gas, the carrier complex is crystallised into small spherical particles. When the carrier thus activated is brought into contact with a titanium halide, such as titanium tetrachloride, TiCl
4
, and the crystal solvent is eliminated, a large amount of catalytically active complexes between the carrier substance, such as MgCl
2
, and the titanium halide, such as titanium tetrachloride, TiCl
4
, are formed on the surface of the solid carrier.
There is now invented a novel composition that consists of magnesium, titanium, halogen and a carboxylic acid ester and is in the liquid state and preferably soluble. There is also invented a method by which the said composition in the liquid state is brought about. The composition is prepared by bringing into contact with each other at a prescribed temperature and reacting the complex MgX
1
2
.nR
1
OH, where X
1
is a halogen, R
1
is a C
1
-C
20
alkyl, and n is in the range 2.0-6.4, a titanium tetrahalide, TiX
2
4
, where X
2
is a halogen, and a carboxylic acid ester, to yield a reaction product. In the course of the preparation, the composition is brought into the liquid state by using:
(a) as the said carboxylic acid ester, a compound that contains at least 8·j carbon atoms and is compatible with the following formula (I)
R
2
(COOR
3
)
j
(I)
where R
2
is a j-valent substituted or unsubstituted C
1
-C
34
hydrocarbon group, R
3
is a C
6
-C
20
alkyl group, and j is an integer from 1 to 4;
(b) a molar ratio R
2
(COOR
3
)
j
/MgX
1
.nR
1
OH that is≧approximately 0.8/j;
(c) a molar ratio TiX
2
4
/MgX
1
2
.nR
1
OH that is≧approximately n;
(d) possibly an organic dissolvent substance S; and
(e) a temperature that is in the range 40-200° C.
Thus, it has been realised that the previous heterogeneous reaction among the solid complex MgX
1
2
.nR
1
OH, a titanium tetrahalide, TiX
2
4
, and an ester-like inner composition can be altered to a homogeneous reaction if the above-mentioned conditions (a)-(e) are met. By using a greater than usual amount of a more dissolvent carboxylic acid ester in combination with an excess amount of titanium tetrahalide and/or an organic dissolvent substance at a more or less elevated temperature, the composition is surprisingly obtained in the liquid state, usually in dissolved form.
An embodiment of the invention uses such a molar ratio TiX
2
4
/MgX
1
2
.nR
1
OH as yields the resultant composition as dissolved in the excess amount of titanium tetrahalide (in respect of the alcohol, R
1
OH). As it is, the titanium tetrahalide reacts with the alcohol of the said complex so that an excess amount of titanium tetrahalide in respect of the alcohol in the complex is required to dissolve the said complex. Titanium tetrahalide and the said complex are brought into contact with each other at a molar ratio TiX
2
4
/MgX
1
2
.nR
1
OH that is preferably ≧1.7.n, and with n in the range 2.0-6.4 (see above), the said ratio is more preferably in the range 10-100 and most preferably in the range 20-50.
The molar ratio between the said carboxylic acid ester and the said complex may vary in a wide range, provided it is ≧approximately 0.8/j (see above). j is the number of carboxyl ester groups of the carboxylic acid ester. When the said carboxylic acid ester reacts with titanium tetrahalide and the said complex, the said carboxyl ester groups function as the electron-donating groups of the carboxylic acid ester. Since a limited number of coordination sites are formed in the mixture, a greater molar amount of the carboxylic acid ester is needed to fill these sites if there are few carboxyl ester groups, i.e., if j is small. Therefore, the above-presented minimum molar ratio depends on the number of carboxyl ester groups in the carboxylic acid ester. For instance, if a dicarboxylic acid is used, j=2 and the said molar ratio between the carboxylic acid ester and the complex is ≧0.8/2, or ≧0.4. The molar ratio between the said carboxylic acid ester and the complex is preferably ≧approximately 1/j and most preferably in the range of approximately 1/j-20/j.
As mentioned above, the said composition is obtained in the liquid state by heating the composition to a temperature of 40 to 200° C. The temperature to be applied depends on the identities and quantities of the carboxylic acid ester, titanium tetrahalide and possible organic dissolvent substance used, and therefore the scope of protection of the invention, with regard to the temperature applied, should in this context be interpreted according to the equivalence principle. The preferable temperature is 60° C. to approximately 140° C. and the most preferable temperature in the range 80-120° C.
Thus, a composition according to the invention is brought about by means of a carboxylic acid ester compatible with formula (I). It is preferable t
Ala-Huikku Sirpa
Garoff Thomas
Leinonen Timo
Borealis A/S
Choi Ling-Siu
Wu David W.
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