Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Polymers from only ethylenic monomers or processes of...
Reexamination Certificate
2000-11-07
2002-04-30
Wu, David W. (Department: 1713)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Polymers from only ethylenic monomers or processes of...
C526S115000, C526S116000, C526S117000, C526S161000, C526S172000, C526S348000, C502S117000, C502S155000
Reexamination Certificate
active
06380327
ABSTRACT:
FIELD OF THE INVENTION
1,4-Cyclohexadienes and triarylmethanes act as chain transfer agents (“CTA”) in the polymerization of olefins in which late transition metal complexes of neutral bidentate ligands are used as a polymerization catalyst.
TECHNICAL BACKGROUND
Polymerization of olefins using early transition metal containing catalysts such as vanadium and zirconium is a well known and commercially important technology. In many instances it is desirable to lower the molecular weight of the polyolefin that would normally be produced. For example lower molecular weight polymers are usually considered easier to melt process, since they have lower melt viscosities. While polymerization process conditions can sometimes be altered to change the molecular weight of the resulting polyolefin, often a CTA such as hydrogen is deliberately added to the process to lower the polyolefin molecular weight.
The polymerization of olefins using late transition metal containing catalysts such as nickel with selected neutral bidentate ligands is known, see for instance U.S. Pat. Nos. 5,714,556, 5,880,241, 6,103,658 and WO00/06620 (corresponding to U.S. patent application Ser. No. 09/362432, filed Jul. 28, 1999), all of which are incorporated by reference herein for all purposes as if fully set forth. Methods for lowering the molecular weight of polyolefins produced in such processes are known. However, the CTAs that have been reported, such as hydrogen, are not very efficient and often tend to reduce the productivity of the polymerization catalyst. Since these processes often give polyolefins with unique and valuable structures, improved methods for controlling the polymer molecular weight are desirable.
WO99/61492 (corresponding to U.S. patent application Ser. No. 09/317,557, filed May 24, 1999), also incorporated by reference herein for all purposes as if fully set forth, describes the use of hydrogen and other types of compounds as CTAs for late metal transition complexes of bidentate ligands as polymerization catalysts. No mention is made of the use of the compounds described herein as CTAs.
SUMMARY OF THE INVENTION
This invention concerns a process for the polymerization of one or more polymerizable olefins, comprising the step of contacting, under polymerization conditions:
(a) said one or more polymerizable olefins and
(b) an active polymerization catalyst comprising a complex of a neutral bidentate ligand of a metal selected from the group consisting of nickel, iron and cobalt,
in the presence of a chain transfer agent comprising a compound selected from the group consisting of a compound of the formula (I)
and a triarylmethane of the formula R
7
3
CH (II), wherein:
each of R
1
, R
2
, R
3
, R
4
, R
5
and R
6
is independently hydrogen, hydrocarbyl, or substituted hydrocarbyl, provided that any two of R
1
, R
2
, R
3
, R
4
, R
5
and R
6
vicinal to one another taken together may form a ring; and
each R
7
is independently aryl or substituted aryl, provided that any two of R
7
taken together may form a ring.
In another form, this invention concerns an improved process for the polymerization of one or more polymerizable olefins in the presence of, as an active polymerization catalyst, a complex of a neutral bidentate ligand of a metal selected from the group consisting of nickel, iron and cobalt, and further in the presence of an effective amount of a chain transfer agent, wherein the improvement comprises using as a chain transfer agent a compound selected from the group consisting of a compound of the formula (I)
and a triarylmethane of the formula R
7
3
CH (II), wherein:
each of R
1
, R
2
, R
3
, R
4
, R
5
and R
6
is independently hydrogen, hydrocarbyl, or substituted hydrocarbyl, provided that any two of R
1
, R
2
, R
3
, R
4
, R
5
and R
6
vicinal to one another taken together may form a ring; and
each R
7
is independently aryl or substituted aryl, provided that any two of R
7
taken together may form a ring.
This invention also concerns a process for the polymerization of one or more polymerizable olefins, comprising the step of contacting:
(a) said one or more polymerizable olefins;
(b) an effective amount of a chain transfer agent selected from the group consisting of
and a triarylmethane of the formula R
7
3
CH (II);
(c) an active polymerization catalyst which contains a nickel, iron or cobalt complex of a ligand of the formula (IV), (V), (VI) or (VII)
wherein:
each of R
1
, R
2
, R
3
, R
4
, R
5
and R
6
is independently hydrogen, hydrocarbyl, or substituted hydrocarbyl, provided that any two of R
1
, R
2
, R
3
, R
4
, R
5
and R
6
vicinal to one another taken together may form a ring;
each R
7
is independently aryl or substituted aryl, provided that any two of R
7
taken together may form a ring;
R
13
and R
16
are each independently hydrocarbyl or substituted hydrocarbyl, provided that the atom bound to the imino nitrogen atom has at least two carbon atoms bound to it;
R
14
and R
15
are each independently hydrogen, hydrocarbyl, substituted hydrocarbyl, or R
14
and R
15
taken together are hydrocarbylene or substituted hydrocarbylene to form a carbocyclic ring;
R
18
is hydrocarbyl or substituted hydrocarbyl, and R
20
is hydrogen, hydrocarbyl or substituted hydrocarbyl or R
18
and R
20
taken together form a ring;
R
19
is hydrocarbyl or substituted hydrocarbyl, and R
21
is hydrogen, substituted hydrocarbyl or hydrocarbyl, or R
19
and R
21
taken together form a ring;
each R
17
is independently hydrogen, substituted hydrocarbyl or hydrocarbyl, or two of R
17
taken together form a ring;
R
22
and R
23
are each independently hydrocarbyl or substituted hydrocarbyl, provided that the atom bound to the imino nitrogen atom has at least two carbon atoms bound to it;
R
24
and R
25
are each independently hydrogen, hydrocarbyl, or substituted hydrocarbyl;
each R
26
is independently hydrogen, hydrocarbyl or substituted hydrocarbyl;
R
27
and R
30
are independently hydrocarbyl or substituted hydrocarbyl; and
R
28
and R
29
are each independently hydrogen, hydrocarbyl or substituted hydrocarbyl.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Herein, certain terms are used. Some of them are:
A “hydrocarbyl group” is a univalent group containing only carbon and hydrogen. As examples of hydrocarbyls may be mentioned unsubstituted alkyls, cycloalkyls and aryls. If not otherwise stated, it is preferred that hydrocarbyl groups herein contain 1 to about 30 carbon atoms.
By “saturated hydrocarbyl” is meant a univalent radical that contains only carbon and hydrogen, and contains no carbon-carbon double bonds, triple bonds and aromatic groups.
By “substituted hydrocarbyl” herein is meant a hydrocarbyl group that contains one or more substituent groups which are inert under the process conditions to which the compound containing these groups is subjected (e.g., an inert functional group, see below). The substituent groups also do not substantially detrimentally interfere with the polymerization process or operation of the polymerization catalyst system. If not otherwise stated, it is preferred that substituted hydrocarbyl groups herein contain 1 to about 30 carbon atoms. Included in the meaning of “substituted” are chains or rings containing one or more heteroatoms, such as nitrogen, oxygen and/or sulfur, and the free valence of the substituted hydrocarbyl may be to the heteroatom. In a substituted hydrocarbyl, all of the hydrogens may be substituted, as in trifluoromethyl.
By “(inert) functional group” herein is meant a group, other than hydrocarbyl or substituted hydrocarbyl, that is inert under the process conditions to which the compound containing the group is subjected. The functional groups also do not substantially interfere with any process described herein that the compound in which they are present may take part in. Examples of potential functional groups include halo, ester, keto (oxo), amino, imino, carboxyl, phosphite, phosphonite, phosphine, phosphinite, thioether, amide, nitrile, and ether. Preferred functional groups are halo, ester, amino, imino, carbox
E. I. du Pont de Nemours and Company
Harlan R.
Wu David W.
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