Patent US4018703A successfully refreshed from Google Patents.
US4018703A
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Corrosion inhibitors
Assignee: Imperial Chemical Industries Ltd
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Filing: 1975-09-29
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Granted: 1977-04-19
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Expires: 1995-09-29
Abstract
Abstract Inhibition of corrosion of steel, especially stainless steel in acid media, using a nitro-aromatic compound which contains a benzene ring substituted by at least one carboxyl substituent, for example dinitrosalicylic acid.
Inventors
- 👤 Mervyn Edward Dennant Turner
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 18:55
CPC Classifications
C; C23; C23F; C23F11/00; C23F11/04
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
60 words
A method of inhibiting the corrosion of steel which in use is contacted with a sulphuric acid or oleum medium which corrodes said steel which comprises maintaining in the medium contacting said steel an amount of a compound selected from the group consisting of dinitrosalicylic acid, nitrophthalic acid, mononitroterephthalic acid and dinitroterephthalic acid effective to inhibit corrosion of the steel.
Claim 2
Independent Claim
60 words
A method of inhibiting the corrosion of steel which in use is contacted with a sulphuric acid or oleum medium which corrodes said steel which comprises maintaining in the medium contacting said steel an amount of a compound selected from the group consisting of dinitrosalicylic acid, nitrophthalic acid, mononitroterephthalic acid and dinitroterephthalic acid effective to inhibit corrosion of the steel.
Claim 3
Dependent Claim
38 words
A method as claimed in claim 1 in which the amount of said compound is in the range 100 p.p.m. to 2% by weight based on the weight of the medium which is in contact with the steel.
Claim 4
Dependent Claim
38 words
A method as claimed in claim 1 in which the amount of said compound is in the range 100 p.p.m. to 0.1% by weight based on the weight of the medium which is in contact with the steel.
Claim 5
Dependent Claim
22 words
A method as claimed in claim 2 in which the said compound is added to the medium in contact with the steel.
Claim 6
Dependent Claim
20 words
A method as claimed in claim 1 in which the said compound is generated in situ in the acidic medium.
Claim 7
Dependent Claim
23 words
A method as claimed in claim 5, wherein nitric acid and an aromatic acid are added to the medium to produce said compound.
Claim 8
Dependent Claim
13 words
A method as claimed in claim 1, wherein said compound is dinitrosalicylic acid.
References Cited (Backward Citations)
US2717196A
Cited
US2630380A
Cited
US3200078A
Cited
US3281278A
Cited
US3294501A
Cited
US3896044A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1980-04-18 | 1980-10-18 | 1981-04-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-04-18 | 1984-10-18 | 1985-04-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-04-18 | 1988-10-18 | 1989-04-19 | $7700.00 | Window Closed / Lapsed |