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
1998-06-09
2001-09-25
Wood, Elizabeth D. (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...
C502S102000, C502S103000, C502S118000, C502S125000, C502S126000
Reexamination Certificate
active
06294497
ABSTRACT:
The present invention relates to catalyst components for the polymerization of olefins, to the catalyst obtained therefrom and to the use of said catalysts in the polymerization of olefins CH
2
═CHR in which R is hydrogen or a hydrocarbyl radical with 1-12 carbon atoms. In particular the present invention relates to catalyst components, suitable for the stereospecific polymerization of olefins, comprising a titanium compound having at least a Ti-halogen bond and an electron donor compound selected from esters of malonic acid having a particular formula supported on a Mg halide. Said catalyst components when used in the polymerization of olefins, and in particular of propylene, are capable to give polymers in high yields and with high isotactic index expressed in terms of high xylene insolubility.
The use of some esters of malonic acid as internal electron donors in catalysts for the polymerization of propylene is already known in the art.
In EP-A45977 is disclosed the use of an ester of the malonic acid (diethyl diisobutylmalonate) as internal donor of a catalyst for the polymerization of olefins. EP-A-5,86473 discloses a catalyst for the polymerization of olefins comprising (a) an alkyl compound, (b) an electron donor compound having certain reactivity features towards MgCl
2
and (c) a solid catalyst component comprising, supported on MgCl
2
, a Ti halide and an electron donor selected from many classes of ester compounds including malonates. In particular, the use of diethyl allylmalonate and di-n-butyl malonate as internal donors in a catalyst for the polymerization of propylene is exemplified. From EP-A-86644 is known the use of diethyl n-butyl malonate and diethyl isopropylmalonate as internal donors in Mg-supported catalysts for the polymerization of propylene in which the external donor is a heterocyclic compound or a ketone. The European patent EP-B-125911 discloses a process for producing (co)polymers which comprises (co)polymerizing at least one olefin, optionally with a diolefin, in the presence of a catalyst composed of (a) a solid catalyst component containing Mg, Ti and an electron donor compound selected from esters of polycarboxylic acids, (b) an organometallic compound of a metal selected from group I to III of the periodic table, and (c) an organosilicon compound having a Si—O—C or a Si—N—C bond. Examples of preferred ester compounds include diethyl methylmalonate, diethyl butylmalonate, diethyl phenylmalonate, diethyl diethylmalonate, and diethyl dibutylmalonate. Only the use of a catalyst containing diethyl phenylmalonate has been exemplified in the preparation of polypropylene.
However, a common drawback experienced in the use of the above mentioned malonates was represented by a poor polymerization yield and/or a not suitable isotactic index of the final polymer.
JP-08157521 relates to a process for preparing a solid catalyst component for polymerization of olefins which is characterized by contacting a solid catalyst component produced by the reaction among a magnesium compound, a titanium compound and an halogen compound, with one or more electron donating compounds represented by the general formula:
wherein R
c
and R
d
are, the same or different, a straight-chain or branched-chain hydrocarbon group having 1-10 carbon atoms, and R
a
and R
b
are the same or different, a saturated or cyclic saturated hydrocarbon group containing one or more secondary or tertiary carbons and having 3-20 carbon atoms.
Said patent application does not provide any indication regarding the effect of the substituents R
c
and R
d
upon the yield of the catalyst in the polymerization process. In particular, the use of specific electron donor compounds of formula (I) in which Rc and Rd are hydrocarbon groups having more than 3 carbon atoms is neither mentioned nor exemplified.
It has now surprisingly been found that if specific esters of malonic acid are used as internal donor, catalyst components capable to give an excellent balance between polymerization yield and isotactic index of the polymer are obtained.
It is therefore an object of the present invention to provide a solid catalyst component for the polymerization of olefins CH
2
═CHR in which R is hydrogen or a hydrocarbyl radical with 1-12 carbon atoms, comprising a titanium compound, having at least a Ti-halogen bond, and an electron donor compound supported on a Mg halide, in which said electron donor is selected from esters of malonic acids of formula (I):
wherein R
1
is H or a C
1
-C
20
linear or branched alkyl, alkenyl, cycloalkyl, aryl, arylalkyl or alkylaryl group; R
2
is a C
1
-C
20
linear or branched alkyl, alkenyl, cycloalkyl, aryl, arylalkyl or alkylaryl group; R
3
and R
4
are independently selected from C
4
-C
20
linear or branched alkyl, cycloalkyl, alkylcycloalkyl, primary arylalkyl or primary alkylaryl; preferably, they are primary branched C
4
-C
20
alkyl groups such as isobutyl or neopentyl groups. When R
1
is H, R
2
is preferably a linear or branched C
3
-C
20
alkyl, cycloalkyl, arylalkyl group; more preferably R
2
is a C
3
-C
20
secondary alkyl, cycloalkyl, or arylalkyl group. Particularly preferred are also compounds of formula (I) in which R
1
is H and R
2
is a C
5
-C
20
primary linear or branched alkyl, a C
5
-C
20
cycloalkyl, a C
7
-C
20
arylalkyl or alkylaryl group. Specific examples of preferred monosubstituted malonate compounds are di-n-butyl 2-isopropyl, diisobutyl 2-isopropyl, dineopentyl 2-isopropyl, dineopentyl 2-tetradecyl, di-n-butyl 2-decyl.
It has been found that the use of the electron donors of the formula (I) in the catalyst components according to the present invention results in higher yields and higher isotactic polymers with respect to those obtained by using the catalyst components containing the malonates of the prior art as internal donors.
The magnesium halide is preferably MgCl
2
in active form which is widely known from the patent literature as a support for Ziegler-Natta catalysts. Patents U.S. Pat. No. 4,298,718 and U.S. Pat. No. 4,495,338 were the first to describe the use of these compounds in Ziegler-Natta catalysis. It is known from these patents that the magnesium dihalides in active form used as support or co-support in components of catalysts for the polymerization of olefins are characterized by X-ray spectra in which the most intense diffraction line that appears in the spectrum of the non-active halide is diminished in intensity and is replaced by a halo whose maximum intensity is displaced towards lower angles relative to that of the more intense line.
The preferred titanium compounds used in the catalyst component of the present invention are TiCl
4
and TiCl
3
; furthermore, also Ti-haloalcoholates of formula Ti(OR)
n-y
X
y
, where n is the valence of titanium and y is a number between 1 and n, can be used.
The preparation of the solid catalyst component can be carried out according to several methods.
According to one of these methods, the magnesium dichloride in an anhydrous state, the titanium compound and the electron donor compound of formula (I) are milled together under conditions in which activation of the magnesium dichloride occurs. The so obtained product can be treated one or more times with an excess of TiCl
4
at a temperature between 80 and 135° C. This treatment is followed by washings with hydrocarbon solvents until chloride ions disappeared. According to a further method, the product obtained by co-milling the magnesium chloride in an anhydrous state, the titanium compound and the electron donor compound of formula (I) is treated with halogenated hydrocarbons such as 1,2-dichloroethane, chlorobenzene, dichloromethane etc. The treatment is carried out for a time between 1 and 4 hours and at temperature of from 40° C. to the boiling point of the halogenated hydrocarbon. The product obtained is then generally washed with inert hydrocarbon solvents such as hexane.
According to another method, magnesium dichloride is preactivated according to well known methods and then treated with an excess of TiCl
4
at a t
Albizzati Enrico
Balbontin Giulio
Chadwick John
Cristofori Antonio
Morini Giampiero
Bryan Cave LLP
Montell Technology Company BV
Wood Elizabeth D.
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