US3989637A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Corrosion inhibitors and processes for using the same
Assignee: Monsanto Co
•
Filing: 1975-06-02
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Granted: 1976-11-02
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Expires: 1995-06-02
Abstract
Abstract Carboxylated lactones of the general formula R1 O=C---C ANGLE ¦¦R2 OO ANGLE CH ¦ R3 wherein R1 and R2 are individually selected from hydrogen, hydroxy, alkyl, hydroxyalkyl, -COOM, -CHOHCOOM, -CH2COOM and a 1,3-dioxolane, 5-oxo group, and R3 is selected from hydrogen and -COOM, wherein M is hydrogen, alkali metal, ammonium or alkylammonium, provided that at least one of R1, R2 and R3 contain a carboxyl group, are disclosed as inhibiting the corrosion of metals by oxygen-bearing waters. The carboxylated lactones can be employed either alone or in combination with thiols, 1,2,3-triazoles, zinc salts, chromates, silicates, inorganic phosphates, molybdates, tannins, lignins, lignin sulfonates, 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
2026-10-26 06:42
CPC Classifications
C; C23; C23F; C23F11/00; C23F11/08; C23F11/10; C23F11/12; C23F11/128; C02; C02F; C02F5/00; C02F5/08; C02F5/10; C07; C07D; C07D317/00; C07D317/08; C07D317/10; C07D317/32; C07D317/34
Claims Analysis
Total Claims: 23
Claim 1
Independent Claim
98 words
A method of inhibiting the corrosion of metals in contact with an aqueous corrosive medium which comprises maintaining in said medium a carboxylated lactone having the formula ##EQU2## wherein R 1 and R 2 are individually selected from the group consisting of hydrogen, hydroxy, alkyl, hydroxyalkyl, --COOM, --CHOHCOOM, --CH 2 COOM and a 1,3-dioxolane, 5-oxo group, and R 3 is selected from hydrogen and --COOM, wherein M is selected from the group consisting of hydrogen, alkali metal, ammonium and alkylammonium, provided that at least one of R 1 , R 2 and R 3 contains a carboxyl group.
Claim 2
Independent Claim
98 words
A method of inhibiting the corrosion of metals in contact with an aqueous corrosive medium which comprises maintaining in said medium a carboxylated lactone having the formula ##EQU2## wherein R 1 and R 2 are individually selected from the group consisting of hydrogen, hydroxy, alkyl, hydroxyalkyl, --COOM, --CHOHCOOM, --CH 2 COOM and a 1,3-dioxolane, 5-oxo group, and R 3 is selected from hydrogen and --COOM, wherein M is selected from the group consisting of hydrogen, alkali metal, ammonium and alkylammonium, provided that at least one of R 1 , R 2 and R 3 contains a carboxyl group.
Claim 3
Dependent Claim
26 words
The method of claim 1 wherein the amount of said carboxylated lactone maintained in said medium is from about 3 to about 500 parts per million.
Claim 4
Dependent Claim
24 words
The method of claim 1 wherein the amount of said carboxylated lactone maintained in said medium is at least about 3 parts per million.
Claim 5
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 6
Dependent Claim
10 words
The method of claim 1 wherein each M is hydrogen.
Claim 7
Dependent Claim
15 words
The method of claim 1 wherein at least one M is an alkali metal ion.
Claim 8
Dependent Claim
14 words
The method of claim 1 wherein at least one M is an ammonium ion.
Claim 9
Dependent Claim
12 words
The method of claim 6 wherein at least one M is hydrogen.
Claim 10
Dependent Claim
19 words
The method of claim 1 wherein at least one of R 1 and R 2 is --CH 2 COOM.
Claim 11
Dependent Claim
10 words
The method of claim 1 wherein R 3 is --COOM.
Claim 12
Dependent Claim
15 words
The method of claim 1 wherein R 1 or R 2 is, 1,3-dioxolane, 5-oxo group.
Claim 13
Dependent Claim
50 words
The method of claim 1 wherein at least one inhibited metal is copper and 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 14
Dependent Claim
17 words
The method of claim 1 wherein the lactone is the acid or salt of 1,3-dioxolane-4-acetic acid, 5-oxo.
Claim 15
Dependent Claim
16 words
The method of claim 1 wherein the lactone is the acid or salt of 1,3-dioxolane-2-carboxy-4-methyl, 5-oxo.
Claim 16
Dependent Claim
16 words
The method of claim 1 wherein the lactone is the acid or salt of 1,3-dioxolane-2-carboxy, 5-oxo.
Claim 17
Dependent Claim
18 words
The method of claim 1 wherein the lactone is the acid or salt of 1,3-dioxolane-4-hydroxy acetic acid, 5-oxo.
Claim 18
Dependent Claim
17 words
The method of claim 1 wherein the lactone is the acid or salt of 2,2'-dicarboxy-4,4'-bis(1,3-dioxolane, 5 oxo).
Claim 19
Dependent Claim
16 words
The method of claim 1 wherein the lactone is the acid or salt of 2,2'-dicarboxy-4,4'-bis(1,3-dioxolane-4-hydroxy, 5-oxo).
Claim 20
Independent Claim
42 words
The 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 the acid or alkali metal, ammonium or alkylammonium salt of 1,3-dioxolane-4,4-diacetic acid, 5-oxo.
Claim 21
Independent Claim
42 words
The 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 the acid or alkali metal, ammonium or alkylammonium salt of 1,3-dioxolane-4,4-diacetic acid, 5-oxo.
Claim 22
Independent Claim
42 words
The 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 the acid or alkali metal, ammonium or alkylammonium salt of 1,3-dioxolane-2-carboxy-4,4-diacetic acid, 5-oxo.
Claim 23
Independent Claim
42 words
The 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 the acid or alkali metal, ammonium or alkylammonium salt of 1,3-dioxolane-2-carboxy-4,4-diacetic acid, 5-oxo.
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) | 1979-11-02 | 1980-05-03 | 1980-11-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-11-02 | 1984-05-03 | 1984-11-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-11-02 | 1988-05-03 | 1988-11-02 | $7700.00 | Window Closed / Lapsed |