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
2003-06-06
2004-03-02
Lu, Caixia (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...
C502S128000, C526S124300, C526S124900, C526S125300, C526S128000
Reexamination Certificate
active
06699814
ABSTRACT:
The present invention relates to catalyst components for the polymerization of olefins, to the catalysts 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 Ti, Mg, halogen and an electron donor compound selected from heteroatom containing esters of malonic acids (heteroatom containing malonates). 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-A-45977 is disclosed the use of an ester of malonic acid (diethyl 2,2-diisobutylmalonate) as internal donor of a catalyst for the polymerization of olefins. EP-A-86473 discloses a catalyst for the polymerization of olefins comprising (a) an Al-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. None of the above-cited applications discloses malonates containing heteroatoms. The same applies to EP-A-86644 that discloses the use of diethyl 2-n-butyl malonate and diethyl 2-isopropylmalonate as internal donors in Mg-supported catalysts for the polymerization of propylene.
It is apparent from the analysis of the polymerization results reported in the above-mentioned applications that a common drawback experienced in the use of the mentioned malonates was represented by a still unsatisfactory polymerization yield and/or a not suitable isotactic index of the final polymer. This is confirmed also by the disclosure of JP-08157521. This application 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. Although an improvement in terms of yields and isotactic index over the previously cited documents is obtained, the results are still not satisfactory for an economical use of the catalyst components disclosed therein.
It has now surprisingly been found that the polymerization yields and the isotactic index of the polymer can be improved by using catalyst components comprising heteroatom containing malonates as internal donors.
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 hydrocarbon radical with 1-12 carbon atoms, comprising Mg, Ti, halogen and an heteroatom containing malonate.
The term heteroatom means any atom, different from C and H, in addition to the oxygen atoms deriving from the malonic acid.
In particular, the electron donor compounds can be selected from esters of malonic acids of formula (I):
wherein R
1
and R
2
equal to or different from each other, are H or a C
1
-C
20
linear or branched alkyl, alkenyl, cycloalkyl, aryl, arylalkyl or alkylaryl group and said R
1
and R
2
can also be joined to form a cyclic group; R
3
and R
4
are independently selected from C
1
-C
20
linear or branched alkyl, alkenyl, cycloalkyl, aryl, arylalkyl or alkylaryl group and R
3
and R
4
can also be joined to form a cyclic group; with the proviso that at least one of the R
1
to R
4
groups contains at least one heteroatom selected from the group consisting of halogens, N, O, Si, Ge, P, and S.
The heteroatoms, are preferably selected from the group consisting of F, Cl, Br, and Si, and, in a preferred embodiment, they are contained in the R
1
or R
2
groups.
Preferably, R
3
and R
4
are primary alkyl, arylalkyl or alkylaryl groups having from 2 to 8 carbon atoms which may contain heteroatoms. More preferably, they are primary branched alkyl groups optionally containing heteroatoms. Examples of suitable R
3
and R
4
groups not containing heteroatoms are methyl, ethyl, n-propyl, n-butyl, isobutyl, neopentyl, 2-ethylhexyl. Examples of suitable R
3
and R
4
groups containing heteroatoms are 2-chloroethyl, 1-trifluoromethylethyl, 2-trifluoromethylpropyl 2-trimethylsilylethyl, 2-bromoethyl, 2-trifluoromethylpropyl, 4-chlorobenzyl, 2-fluoroethyl, 3-trimethylsilylallyl.
R
2
is preferably, and particularly when R
1
is H, 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. 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. Preferably R
2
contains at least one heteroatom. Specific examples of suitable monosubstituted malonate compounds are diethyl 2-(1-trifluoromethylethyl) malonate, diethyl 2-(1-trifluoromethylethylidene)malonate, bis(2-chloroethyl) 2-isopropylmalonate, diethyl 2-(trimethylsilylmethyl)malonate, diethyl 2-p-chlorobenzylmalonate, diethyl 2-piperidyl malonate, diethyl 2-(2-ethylpiperidyl)malonate, diethyl 2-(1-trifluoromethyl-1-methylethyl)malonate, diethyl 2-&agr;-phenyl-p-(trifluoromethyl)benzyl malonate, bis(2-fluoroethyl) 2-isopropylmalonate, bis(2-fluoroethyl) 2-ethylmalonate.
Among disubstituted malonates preferred compounds are those in which at least one of R
1
and R
2
is a primary C
3
-C
20
alkyl, cycloalkyl, arylalkyl group.
Specific examples of suitable disubstituted malonate compounds are: diethyl-2(1-trifluoromethylethyl)-2-benzylmalonate, diethyl 2-(1-trifluoromethylethyl)-2-methylmalonate, diethyl 2-methyltrimethylsilyl-2-methylmalonate, diethyl 2-p-chlorobenzyl-2-isopropylmalonate, diethyl 2-piperidyl-2-methylmalonate, diethyl 2-(1-trifluoromethyl-1-methylethyl)-2-methylmalonate, bis(2-trimethylsilylethyl) 2-isopropyl-2-isobutylmalonate bis(p-chlorobenzyl) 2-cyclohexyl-2-methylmalonate.
It has been surprisingly found that catalyst components in which the internal donor is a heteroatom containing malonate perform better, in term of yields and isotactic index, than catalyst components comprising analogous malonates not containing heteroatoms.
As explained above, catalyst components according to the invention comprise, in addition to the above electron donor, Ti, Mg and halogen. In particular, the catalyst component comprises a titanium compound, having at least a Ti-halogen bond and the above mentioned electron donor compound supported on a Mg halide. 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. Nos. 4,298,718 and 4,495,388 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 intense 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-ha
Balbontin Giulio
Gulevich Yuri V.
Morini Giampiero
Basell Poliolefine Italia S.p.A.
Lu Caixia
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