US4944926A
Expired / Lapsed
US
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Method to treat rhodium-containing solutions
Assignee: Polysar Ltd
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Filing: 1988-08-01
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Granted: 1990-07-31
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Expires: 2008-08-01
Abstract
Abstract The present invention provides a method to treat a rhodium containing solution which is derived from the catalytic hydrogenation of nitrile rubber. An additive selected from thiourea, polysaccharide and carbon black is used to cause a rhodium-containing precipitate. The precipitate is then separated from the solution by, for example, filtration or centrifugation.
Inventors
- 👤 Akhtar Osman
- 👤 William G. Bradford
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 12:29
CPC Classifications
C; C08; C08C; C08C19/00; C08C19/02; C08C2/00; C08C2/02; C08C2/04
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
52 words
A process to treat a rhodium-containing rubber solution obtained from the catalytic hydrogenation of nitrile rubber, said process consisting of: (i) adding to said solution an additive selected from thiourea, and polysaccharide, thereby forming a rhodium-containing precipitate which is not soluble in said solution, and (ii) separating said precipitate from said solution.
Claim 2
Dependent Claim
52 words
A process to treat a rhodium-containing rubber solution obtained from the catalytic hydrogenation of nitrile rubber, said process consisting of: (i) adding to said solution an additive selected from thiourea, and polysaccharide, thereby forming a rhodium-containing precipitate which is not soluble in said solution, and (ii) separating said precipitate from said solution.
Claim 3
Dependent Claim
30 words
The process according to claim 1 wherein said polysaccharide additive consists of from 30 to 100 parts by weight of soluble starch per 100 parts by weight of said rubber.
Claim 4
Dependent Claim
19 words
The process according to claim 1 wherein said separating of said precipitate from said solution is completed by centrifugation.
Claim 5
Dependent Claim
30 words
The process of claim 1 wherein said hydrogenated nitrile rubber solution comprises from 5 to 12 parts by weight of said rubber per 100 parts by weight of monochlorobenzene solvent.
Claim 6
Dependent Claim
25 words
The process of claim 4 wherein said additive comprises from 5 to 75 parts by weight thiourea per 100 parts by weight of said rubber.
Claim 7
Dependent Claim
53 words
The process of claim 5 wherein said separating of said precipitate is completed by: (a) adding from 50 to 300 parts by weight of water per 100 parts by weight of thiourea, thereby dissolving said precipitate into said water to form a water solution, and (b) separating said water solution from said solution.
Claim 8
Dependent Claim
16 words
The process of claim 6 wherein said separating of said water solution is completed by decanting.
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) | 1993-07-30 | 1994-01-29 | 1994-07-31 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-07-30 | 1998-01-29 | 1998-07-31 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-07-30 | 2002-01-29 | 2002-07-31 | $7700.00 | Window Closed / Lapsed |