Chromium compounds and olefin polymerization processes...

Details Chromium compounds and olefin polymerization processes... Chromium compounds and olefin polymerization processes...

2003-02-10

2004-10-26

Lu, Caixia (Department: 1713)

Catalyst, solid sorbent, or support therefor: product or process

Catalyst or precursor therefor

Organic compound containing

C502S103000, C502S154000, C526S124200, C526S160000, C526S169000

Reexamination Certificate

active

06809057

ABSTRACT:

FIELD
Embodiments of our invention relate to organo-chromium compounds and generally to tetra-hydrocarbyl chromium compounds and to their use for the polymerization of olefins.
BACKGROUND
Chromium catalyst systems are known. In the past these systems have included chromium oxides and silyl chromate catalysts. These catalysts however, suffer from relatively sparse or low activity, as measured by the amount of polymer produced per weight unit of catalyst. Further, these previous catalyst systems suffer from a lengthy induction period.
A chromium catalyst system that simultaneously has high activity and reduced induction time would be commercially advantageous.
In Chemical Engineering Science 56 (2001) 4155-4168, the authors suggest alkyl chromium active centers bound to silica by two Si—O—Cr linkages, which are said to coordinate ethylene. Insertion of the coordinated olefin into one of two growing alkyl chains is said to occur, provided there is no &agr;-substituent.
In the Journal of Polymer Science: Part A: Polymer Chemistry, Vol 28, 3587-3601 (1990), the authors suggest synthesis of organochromium compounds, beta-stabilized chromium alkyls for testing catalytic activity in ethylene polymerization. The compounds are purported to exhibit activity when reacted with a partially dehydroxylated high surface area carrier. The poorest supports are said to be silica.
SUMMARY
In one embodiment, this invention includes a catalyst system that is the product of combining: a compound represented by the formula:
CrR
4
wherein each R is independently a hydrocarbyl or substituted hydrocarbyl, with the proviso that R may not be cyclopentadienyl groups; an activator represented by the formula:
MQ
2
,
where M is a Group II metal and is preferably magnesium, and each Q is independently an alkyl, or substituted alkyl the substituents in are preferably selected from one or more of Cl, Br, I, F and SiQ′
3
, where each Q′ is independently a C
1
-C
30
hydrocarbyl or C
1
-C
30
substituted hydrocarbyl; and a support.
In another embodiment, this invention includes a catalyst system, comprising the product of: a compound represented by the formula:
CrR
4
wherein each R is independently a hydrocarbyl or substituted hydrocarbyl where the substituents are selected from one or more of Cl, Br, I, F, and SiR′
3
, where each R′ is independently a C
1
-C
20
hydrocarbyl or C
1
-C
20
substituted hydrocarbyl; with the proviso that R may not be a cyclopentadienyl group; an activator represented by the general formula:
MQ
2
,
where M is a Group II metal, preferably magnesium, and each Q is independently an alkyl, or substituted alkyl wherein the substituents comprise one or more of Cl, Br, I, F or SiQ′
3
, where each Q′ is independently a C
1
-C
30
hydrocarbyl or C
1
-C
30
substituted hydrocarbyl; and a support.
In any embodiment described herein, the catalyst compound hydrocarbyl or substituted hydrocarbyl may have from 1-50 carbon atoms, 1-30 carbon atoms, 1-20 carbon atoms, or 1-10 carbon atoms. The hydrocarbyl in any embodiment described herein may be substituted with one or more Cl, Br, I, F, or SiR′
3
, where each R′ is independently a C
1
-C
30
hydrocarbyl or C
1
-C
30
substituted hydrocarbyl, or a C
1
-C
20
hydrocarbyl or C
1
-C
20
substituted hydrocarbyl. In any embodiment described herein, the catalyst compound may be selected from: Cr(CH
2
SiMe
3
)
4
, Cr(CH
2
CMe
3
)
4
, Cr(CH
2
CMe
2
Ph)
4
, Cr(CH
2
CPh
3
)
4
, and Cr(CH
2
C
6
H
11
)
4
.
In preferred embodiments the activator is selected from MgBu(Et), Mg(n-hexyl)
2
, and MgBu
2
.
Preferred supports include silica, alumina or combinations thereof. The most preferred support is dehydrated silica.
Particularly preferred embodiments include a catalyst system comprising the product of combining: Cr(CH
2
SiMe
3
)
4
, Cr(CH
2
CMe,)
4
, Cr(CH
2
CMe
2
Ph)
4
, Cr(CH
2
CPh
3
)
4
, or Cr(CH
2
C
6
H
11
)
4
; with MgBu(Et), Mg(n-hexyl)
2
, or MgBu
2
; and silica support.
Other embodiments of this invention include a process for polymerizing olefins comprising combining under suitable polymerization conditions: a) a catalyst system comprising the product of: a compound represented by the formula:
CrR
4
wherein each R is independently a hydrocarbyl or substituted hydrocarbyl, with the proviso that R may not be a cyclopentadicnyl group; an activator represented by the formula:
MQ
2
,
where M is a Group II metal, preferably magnesium, and each Q is independently an alkyl, or substituted alkyl. Preferably Q is a substituted hydrocarbyl, said substituents selected from one or more of Cl, Br, I, P, and SiQ′
3
, where each Q′ is independently a C
1
-C
30
hydrocarbyl or C
1
-C
30
substituted hydrocarbyl; and a support; with b) with ethylene; and/or c) one or more &agr;-olefins, preferably one or more of propylene, butene-1, pentene-1, hexene-1, octene-1, decene-1, 2-methyl-propene-1, 3-methylbutene-1, 2-methylbutene-1, 3-methylpentene-1, 4-methylpentene-1, 1,3-butadiene, 1,4-pentadiene, 1,5-hexadiene, 1,4-hexadiene, cyclopentene, cyclohexene, cycloheptene, propyne, butadyne, styrene, and 1,4-dihexyne, 3,3-dimethyl-1-butene; 1-pentene comprising one or more methyl, ethyl or propyl substituents; said 1-hexene comprising one or more methyl, ethyl or propyl substituents; 1-heptene comprising one or more methyl, ethyl or propyl substituents; 1-octene comprising one or more methyl, ethyl or propyl substituents; 1-nonene comprising one or more methyl, ethyl or propyl substituents; ethyl, methyl or dimethyl-substituted 1-decene; 1-dodecene; and styrene. Of these, propylene, butene-1, pentene-1, hexene-1, or octene-1 are most preferred.
Any embodiment of the process described herein may further include obtaining a polymer comprising ethylene derived units and units derived from propylene, butene-1, 4-methyl-1-pentene, hexene-1, and/or octene-1.
In any embodiment of the process described herein, each R substituent is independently Cl, Br, I, F, or SiR′
3
, wherein each R′ is independently a C
1
or C
2
-C
30
hydrocarbyl or substituted C
1
or C
2
-C
30
hydrocarbyl.
In any embodiment of the process described herein the catalyst compound may be selected from Cr(CH
2
SiMe
3
)
4
, Cr(CH
2
CMe
3
)
4
, Cr(CH
2
CMe
2
Ph)
4
, Cr(CH
2
CPh
3
)
4
, and Cr(CH
2
C
6
H
11
)
4
.
In any embodiment of the process described herein, the activator may be selected from MgBu(Et), Mg(n-hexyl)
2
, and MgBu
2
.
In any embodiment of the process described herein, the support may include silica, preferably dehydrated.
In one embodiment of the process, the catalyst compound is selected from Cr(CH
2
CMe
3
)
4
, and Cr(CH
2
SiMe
3
)
4
, the activator is selected from MgBu
2
, Mg(n-hexyl)
2
, or MgBuEt, and the support comprises dehydrated silica.
Another embodiment of the process includes combining under suitable polymerization conditions: a) a catalyst system comprising the product of: a compound represented by the formula:
CrR
4
wherein each R independently is a hydrocarbyl or substituted hydrocarbyl, with the proviso that R may not be a cyclopentadienyl group, wherein the hydrocarbyl substituents are one or more of Cl, Br, I, F, or SiR′
3
, where each R′ is independently a C
1
-C
30
hydrocarbyl or substituted hydrocarbyl; an activator represented by the formula:
MQ
2
,
where M is magnesium, and each Q is independently a substituted hydrocarbyl, said substituents selected from one or more of Cl, Br, I, F, or SiQ′
3
, where each Q′ is independently a C
1
-C
30
hydrocarbyl or C
1
-C
30
substituted hydrocarbyl, an alkyl, or substituted alkyl; and a support; with b) with ethylene; and c) butene-1, 4-methyl-1-pentene, hexene-1, and/or octene-1; and d) obtaining a polymer having ethylene derived units and units derived from propylene, butene-1, 4-methyl-1-pentene, hexene-1, and/or octene-1.
Description
Process
In some embodiments, this invention is a process for the polymerization or copolymerization of olefins, comprising activating the tetra-hydrocarbyl chromium catalyst and contacting it with ethylene and

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