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US4719031A
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Polymeric alkylene diphosphonate anhydrides, their production and use
Assignee: Monsanto Co
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Filing: 1987-02-02
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Granted: 1988-01-12
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Expires: 2007-02-02
Abstract
Abstract Polymeric phosphonate anhydrides are formed by dehydrating a reaction mixture comprising a salt of a diphosponic acid. The invention includes the polymeric phosphonate, its method of preparation, and a primary use.
Inventors
- 👤 James P. Coleman
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 22:13
CPC Classifications
C; C08; C08G; C08G79/00; C08G79/02; C08G79/04; C07; C07F; C07F9/00; C07F9/02; C07F9/28; C07F9/38; C07F9/40; C07F9/4071; C07F9/409
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
71 words
A method for inhibiting the formation of scale in an aqueous solution containing scale-forming ions, by incorporating into the aqueous solution an effective amount of phosphate-phosphonate anhydride copolymer of the following formula: ##STR6## where M is an alkali metal; R is an unsubstituted alkylene group; A is hydrogen, an alkali metal, or an ammonium group; X averages from 0 to about 5; and Y is an integer of at least 5.
Claim 2
Independent Claim
71 words
A method for inhibiting the formation of scale in an aqueous solution containing scale-forming ions, by incorporating into the aqueous solution an effective amount of phosphate-phosphonate anhydride copolymer of the following formula: ##STR6## where M is an alkali metal; R is an unsubstituted alkylene group; A is hydrogen, an alkali metal, or an ammonium group; X averages from 0 to about 5; and Y is an integer of at least 5.
Claim 3
Dependent Claim
13 words
The method of claim 1 wherein R is propylene and M is sodium.
Claim 4
Dependent Claim
13 words
The method of claim 1 wherein R is methylene and M is sodium.
Claim 5
Dependent Claim
13 words
The method of claim 1 wherein R is ethylene and M is sodium.
References Cited (Backward Citations)
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1991-01-11 | 1991-07-13 | 1992-01-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-01-11 | 1995-07-13 | 1996-01-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-01-11 | 1999-07-13 | 2000-01-12 | $7700.00 | Window Closed / Lapsed |