US4209487A
Expired / Lapsed
US
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Method for corrosion inhibition
Assignee: Solutia Inc
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Filing: 1976-04-15
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Granted: 1980-06-24
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Expires: 1996-04-15
Abstract
Abstract 1,2-Ethane diphosphonates of the general formula M2O3P-CH2CH2-PO3M2 wherein M is hydrogen, metal ion, ammonium, alkyl ammonium or mixtures thereof, are disclosed as inhibiting the corrosion of metals by oxygen-bearing waters. The 1,2-ethane diphosphonates can be employed either alone or in combination with certain thiols, 1,2,3-triazoles, zinc salts, chromates, silicates, inorganic phosphates, molybdates, tannins, lignins, lignin sulfonates, certain calcium and magnesium salts and mixtures thereof.
Inventors
- 👤 Ronald D. Hogue
- 👤 Thomas M. King
- 👤 Robert S. Mitchell
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 07:06
CPC Classifications
C; C23; C23F; C23F11/00; C23F11/08; C23F11/10; C23F11/167; C23F11/1676
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
68 words
A method of inhibiting the corrosion of metals in contact with an aqueous corrosive medium which comprises maintaining in said medium at least about 3 parts per million of 1,2-ethane diphosphonic acid or a water soluble salt thereof having the formula M.sub.2 O.sub.3 P--CH.sub.2 CH.sub.2 --PO.sub.3 M.sub.2 wherein each M is individually selected from the group consisting of hydrogen, alkali metal ions, ammonium ions and alkyl ammonium ions.
Claim 2
Independent Claim
68 words
A method of inhibiting the corrosion of metals in contact with an aqueous corrosive medium which comprises maintaining in said medium at least about 3 parts per million of 1,2-ethane diphosphonic acid or a water soluble salt thereof having the formula M.sub.2 O.sub.3 P--CH.sub.2 CH.sub.2 --PO.sub.3 M.sub.2 wherein each M is individually selected from the group consisting of hydrogen, alkali metal ions, ammonium ions and alkyl ammonium ions.
Claim 3
Dependent Claim
26 words
The method of claim 1 wherein the amount of said 1,2-ethane diphosphonate maintained in said medium is from about 3 to about 500 parts per million.
Claim 4
Dependent Claim
23 words
The method of claim 1 wherein the said inhibited metals are selected from the group consisting of ferrous metals, copper, aluminum and brass.
Claim 5
Dependent Claim
9 words
The method of claim 1 comprising 1,2-ethane diphosphonic acid.
Claim 6
Dependent Claim
15 words
The method of claim 1 wherein at least one M is an alkali metal ion.
Claim 7
Dependent Claim
12 words
The method of claim 5 wherein at least two M are hydrogen.
Claim 8
Dependent Claim
14 words
The method of claim 1 wherein at least one M is an ammonium ion.
Claim 9
Dependent Claim
42 words
The method of claim 1 wherein the aqueous medium additionally contains a compound selected from the group consisting of 1,2,3-triazoles, thiols of thiazoles, thiols of oxazoles, thiols of imidazoles and mixtures thereof in an amount of at least 0.05 parts per million.
Claim 10
Independent Claim
31 words
The method of inhibiting the corrosion of metals in contact with an aqueous corrosive medium which comprises maintaining in said medium at least 10 parts per million of 1,2-ethane diphosphonic acid.
Claim 11
Independent Claim
31 words
The method of inhibiting the corrosion of metals in contact with an aqueous corrosive medium which comprises maintaining in said medium at least 10 parts per million of 1,2-ethane diphosphonic acid.
Claim 12
Dependent Claim
18 words
The method of claim 9 wherein the said diphosphonic acid is in the form of the disodium salt.
References Cited (Backward Citations)
US3803048A
Cited
US3738806A
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US3816333A
Cited
US3837803A
Cited
USB336566I5
Cited
US3890228A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1983-06-24 | 1983-12-24 | 1984-06-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1987-06-24 | 1987-12-24 | 1988-06-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1991-06-24 | 1991-12-24 | 1992-06-24 | $7700.00 | Window Closed / Lapsed |