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US4808680A
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Polymerization of vinyl aromatic monomers using cyclopentadienyl zirconium catalysts
Assignee: Dow Chemical Co
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Filing: 1987-06-08
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Granted: 1989-02-28
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Expires: 2007-06-08
Abstract
Abstract Polymers of vinyl aromatic monomers having a high degree of syndiotacticity are prepared by contacting with a catalyst comprising a cyclopentadienyl zirconium (IV) complex and polymethylaluminoxane under polymerization conditions.
Inventors
- 👤 Gregory F. Schmidt
- 👤 Richard E. Campbell, Jr.
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 22:41
CPC Classifications
C; C08; C08F; C08F12/00; C08F12/02; C08F12/04; C08F4/00; C08F4/42; C08F4/44; C08F4/60; C08F4/62; C08F4/64; C08F4/659; C08F4/65912; Y; Y10; Y10S; Y10S526/00; Y10S526/943
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
122 words
A process for the preparation of polymers of vinyl aromatic monomers having a high degree of syndiotacticity comprising contacting one or more vinyl aromatic monomers under polymerization conditions with a catalyst comprising the reaction product of polymethylaluminoxane and a cyclopentadienyl zirconium (IV) complex corresponding to the formula: CpZrR 3 , wherein Cp is a π-bonded cyclopentadienyl or substituted cyclopentadienyl ligand having from 5 to 20 carbons, and R is independently each occurrence selected from the ligand group consisting of halides; alkoxides and aryloxides corresponding to the formula: OR'; amides corresponding to the formula: NR' 2 ; phosphides corresponding to the formula: PR' 2 ; and β-diketonates corresponding to the formula: R'--C(O)--CH--C(O)--R', and R' is alkyl or aryl of up to 12 carbons.
Claim 2
Dependent Claim
122 words
A process for the preparation of polymers of vinyl aromatic monomers having a high degree of syndiotacticity comprising contacting one or more vinyl aromatic monomers under polymerization conditions with a catalyst comprising the reaction product of polymethylaluminoxane and a cyclopentadienyl zirconium (IV) complex corresponding to the formula: CpZrR 3 , wherein Cp is a π-bonded cyclopentadienyl or substituted cyclopentadienyl ligand having from 5 to 20 carbons, and R is independently each occurrence selected from the ligand group consisting of halides; alkoxides and aryloxides corresponding to the formula: OR'; amides corresponding to the formula: NR' 2 ; phosphides corresponding to the formula: PR' 2 ; and β-diketonates corresponding to the formula: R'--C(O)--CH--C(O)--R', and R' is alkyl or aryl of up to 12 carbons.
Claim 3
Dependent Claim
25 words
A process according to claim 1, wherein the monomer is contacted with the catalyst at a temperature from about 25° C. to about 100° C.
Claim 4
Dependent Claim
13 words
A process according to claim 1, wherein an inert diluent is additionally present.
Claim 5
Dependent Claim
20 words
A process according to claim 1, wherein the polymer has a molecular structure containing greater than about 65 percent syndiotactic
Claim 6
Dependent Claim
12 words
A process according to claim 1, wherein R is chloro or phenoxide.
Claim 7
Dependent Claim
21 words
A process according to claim 1, wherein the molar ratio of polymethylaluminoxane to zirconium is from about 10:1 to about 50,000:1.
Claim 8
Dependent Claim
21 words
A process acoording to claim 1, wherein the molar ratio of polymethylaluminoxane to zirconium is from about 100:1 to about 10,000:1.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1992-02-28 | 1992-08-29 | 1993-02-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-02-28 | 1996-08-29 | 1997-02-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-02-28 | 2000-08-29 | 2001-02-28 | $7700.00 | Window Closed / Lapsed |