US5130052A
Expired / Lapsed
US
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Corrosion inhibition with water-soluble rare earth chelates
Assignee: WR Grace and Co Conn
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Filing: 1991-10-24
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Granted: 1992-07-14
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Expires: 2011-10-24
Abstract
Abstract A method of inhibiting corrosion of a metal surface in an aqueous system having a pH of at least 6, comprising maintaining in the aqueous system, in an amount effective to inhibit corrosion, a water-soluble, organic-rare earth metal chelate which is derived from a rare earth metal having an atomic number from 57 to 71 and an organic chelant. The organic chelant provides not only water solubility but surprisingly enhanced corrosion inhibiting activity. The water-soluble, organic-rare earth chelates may be advantageously combined with other corrosion inhibitors such as zinc chelates, organophosphonates, phosphates, chromates, molybdates, and the like.
Inventors
- 👤 Robert P. Kreh
- 👤 Vincent R. Kuhn
- 👤 John Richardson
- 👤 Robert M. Spotnitz
- 👤 Charles G. Carter
- 👤 Vladimir Jovancicevic
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 05:24
CPC Classifications
C; C23; C23F; C23F11/00; C23F11/08
Claims Analysis
Total Claims: 45
Claim 1
Independent Claim
67 words
A method of inhibiting corrosion of metal which is in contact with an aqueous system having a pH of at least 6 comprising maintaining in the aqueous system, in an amount effective to inhibit corrosion of the metal, at least one water-soluble, organic-rare earth metal chelate derived from a rare earth metal having an atomic number in the range 57 to 71 and a water-soluble organic chelant.
Claim 2
Independent Claim
67 words
A method of inhibiting corrosion of metal which is in contact with an aqueous system having a pH of at least 6 comprising maintaining in the aqueous system, in an amount effective to inhibit corrosion of the metal, at least one water-soluble, organic-rare earth metal chelate derived from a rare earth metal having an atomic number in the range 57 to 71 and a water-soluble organic chelant.
Claim 3
Dependent Claim
16 words
The method of claim 1 wherein the organic chelant contains two or more aromatic hydroxy groups.
Claim 4
Dependent Claim
16 words
The method of claim 2 wherein the organic chelant contains one or more carboxylic acid groups.
Claim 5
Dependent Claim
19 words
The method of claim 3 wherein the organic chelant also contains one or more amine or amine oxide groups.
Claim 6
Dependent Claim
11 words
The method of claim 4 wherein the organic chelant is N,N-bis-(2-hydroxy-5-sulfobenzyl)glycine.
Claim 7
Dependent Claim
18 words
The method of claim 4 wherein the organic chelant is a polymer of glycine, formaldehyde and phenolsulfonic acid.
Claim 8
Dependent Claim
17 words
The method of claim 2 wherein the organic chelant also contains one or more sulfonic acid group.
Claim 9
Dependent Claim
12 words
The method of claim 7 wherein the organic chelant is catechol-3,5-disulfonic acid.
Claim 10
Dependent Claim
12 words
The method of claim 7 wherein the organic chelant is catechol-4-sulfonic acid.
Claim 11
Dependent Claim
47 words
The method of claim 1 wherein the organic chelant contains at least four donor groups selected from the group consisting of hydroxy, carboxylic acid, phosphonyl, sulfonic acid, amine, and amine oxide with the proviso that at least two of the groups are carboxylic acid, phosphonyl or hydroxy.
Claim 12
Dependent Claim
12 words
The method of claim 10 wherein the chelant is a carboxylate-containing polymer.
Claim 13
Dependent Claim
18 words
The method of claim 11 wherein the organic chelant contains one or more amine or amine oxide groups.
Claim 14
Dependent Claim
51 words
The method of claim 12 wherein the organic chelant has the following formula: ##STR1## wherein R is independently selected from the group consisting of H, aromatic and alkyl wherein the alkyl group may further contain CO 2 H, NR 2 , SO 3 , PO 3 H 2 or OH groups.
Claim 15
Dependent Claim
11 words
The method of claim 13 wherein the organic chelant is N,N'-bis(2-hydroxysuccinyl)ethylenediamine.
Claim 16
Dependent Claim
17 words
The method of claim 12 wherein the organic chelant is selected from the group consisting of N-(2-hydroxysuccinyl)glycine.
Claim 17
Dependent Claim
22 words
The method of claim 10 wherein the organic chelant contains one or more carboxylic acid groups and one or more hydroxy groups.
Claim 18
Dependent Claim
12 words
The method of claim 16 wherein the organic chelant is citric acid.
Claim 19
Dependent Claim
16 words
The method of claim 16 wherein the organic chelant contains one or more sulfonic acid groups.
Claim 20
Dependent Claim
12 words
The method of claim 18 wherein the organic chelant is 3,5-bis-(di-N,N-(carboxymethyl)aminomethyl)-4-hydroxybenzenesulfonic acid.
Claim 21
Dependent Claim
25 words
The method of claim 10 wherein the organic chelant contains one or more carboxylic acid groups and one or more amine or amine oxide groups.
Claim 22
Dependent Claim
13 words
The method of claim 20 wherein the organic chelant is ethylenediamine tetraacetic acid.
Claim 23
Dependent Claim
13 words
The method of claim 20 wherein the organic chelant is 1,3-propylenediamine tetraacetic acid.
Claim 24
Dependent Claim
13 words
The method of claim 20 wherein the organic chelant is diethylenetriamine pentaacetic acid.
Claim 25
Dependent Claim
23 words
The method of claim 10 wherein the organic chelant contains one or more carboxylic acid groups and one or more sulfonic acid groups.
Claim 26
Dependent Claim
12 words
The method of claim 24 wherein the organic chelant is a polymer.
Claim 27
Dependent Claim
16 words
The method of claim 10 wherein the organic chelant contains one or more phosphonic acid groups.
Claim 28
Dependent Claim
12 words
The method of claim 26 wherein the organic chelant is 2-phosphonobutane-1,2,4-tricarboxylic acid.
Claim 29
Dependent Claim
22 words
The method of claim 10 wherein the organic chelant contains at least one phosphonic acid group and at least one hydroxy group.
Claim 30
Dependent Claim
12 words
The method of claim 28 wherein the organic chelant is 3,5-bis((1,1-diphosphono-ethyl)aminomethyl)-4-hydroxy-benzenesulfonic acid.
Claim 31
Dependent Claim
25 words
The method of claim 10 wherein the organic chelant contains at least one phosphonic acid group and at least one amine or amine oxide group.
Claim 32
Dependent Claim
16 words
The method of claim 30 wherein the organic chelant further contains at least one hydroxy group.
Claim 33
Dependent Claim
12 words
The method of claim 31 wherein the organic chelant is N,N-bis(phosphonomethyl)ethanolamine N-oxide.
Claim 34
Dependent Claim
17 words
The method of claim 30 wherein the organic chelant further contains at least one sulfonic acid group.
Claim 35
Dependent Claim
11 words
The method of claim 33 wherein the organic chelant is N,N-(diphosphonomethyl)taurine.
Claim 36
Dependent Claim
16 words
A method according to claim 1 wherein the effective amount is from 0.10 to 5000 ppm.
Claim 37
Dependent Claim
16 words
A method according to claim 1 wherein the effective amount is from 0.5 to 1000 ppm.
Claim 38
Dependent Claim
16 words
A method according to claim 1 wherein the effective amount is from 1 to 200 ppm.
Claim 39
Independent Claim
78 words
A method of inhibiting corrosion of a metal which is in contact with an aqueous system comprising maintaining in the aqueous system the combination of at least one water-soluble, organic rare earth metal chelate together with a water-soluble organic zinc chelate in an amount effective to inhibit corrosion of the metal, wherein the rare earth metal chelate is derived from a rare earth metal having an atomic number in the range 57 to 71 and an organic chelant.
Claim 40
Independent Claim
78 words
A method of inhibiting corrosion of a metal which is in contact with an aqueous system comprising maintaining in the aqueous system the combination of at least one water-soluble, organic rare earth metal chelate together with a water-soluble organic zinc chelate in an amount effective to inhibit corrosion of the metal, wherein the rare earth metal chelate is derived from a rare earth metal having an atomic number in the range 57 to 71 and an organic chelant.
Claim 41
Dependent Claim
26 words
A method according to claim 38 wherein the weight ratio of rare earth metal chelant to zinc chelate is in the range of 1000:1 to 1:1000.
Claim 42
Dependent Claim
26 words
A method according to claim 38 wherein the weight ratio of rare earth metal chelate to zinc chelate is in the range of 100:1 to 1:100.
Claim 43
Dependent Claim
26 words
A method according to claim 38 wherein the weight ratio of rare earth metal chelate to zinc chelate is in the range of 50:1 to 1:50.
Claim 44
Dependent Claim
51 words
A composition useful for inhibiting corrosion in aqueous systems comprising the combination of at least one water-soluble, organic rare earth metal chelate and a water-soluble organic zinc chelate, wherein the rare earth metal chelate is derived from a rare earth metal having an atomic number in the range 57 to 71.
Claim 45
Dependent Claim
51 words
A composition useful for inhibiting corrosion in aqueous systems comprising the combination of at least one water-soluble, organic rare earth metal chelate and a water-soluble organic zinc chelate, wherein the rare earth metal chelate is derived from a rare earth metal having an atomic number in the range 57 to 71.
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| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
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| 3.5 Years (Year 4) | 1995-07-14 | 1996-01-13 | 1996-07-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1999-07-14 | 2000-01-13 | 2000-07-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2003-07-14 | 2004-01-13 | 2004-07-14 | $7700.00 | Window Closed / Lapsed |