US4935205A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Corrosion inhibition
Assignee: WR Grace and Co Conn
•
Filing: 1988-06-10
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Granted: 1990-06-19
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Expires: 2008-06-10
Abstract
Abstract A method of inhibiting corrosion of iron or iron-based alloys which are in contact with an aqueous system by introducing and maintaining within the system at least one ortho dihydroxyaromatic compound having at least one electron withdrawing group pendant from the aromatic ring.
Inventors
- 👤 Robert P. Kreh
- 👤 Joseph T. Lundquist
- 👤 Wayne L. Henry
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 16:46
CPC Classifications
C; C23; C23F; C23F11/00; C23F11/08; C23F11/10; C23F11/12; C23F11/122; C23F11/124; C23F11/14; C23F11/147; C23F11/16; Y; Y10; Y10S; Y10S507/00; Y10S507/939
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
92 words
A method of inhibiting corrosion of iron based metal which is in contact with an aqueous solution comprising maintaining in the aqueous solution from 0.1 to 50,000 parts per million of at least one dihydroxylaromatic compound represented by the formula: Q Ar (OH).sub.2 wherein Ar represents a single-ring aromatic moiety, Q represents at least one electron withdrawing group substituted on the Ar moiety selected from sulfonic acid, sulfonic acid salts and nitro group, and the hydroxyl (OH) groups are substituted on the Ar moiety in paired position with respect to each other.
Claim 2
Independent Claim
92 words
A method of inhibiting corrosion of iron based metal which is in contact with an aqueous solution comprising maintaining in the aqueous solution from 0.1 to 50,000 parts per million of at least one dihydroxylaromatic compound represented by the formula: Q Ar (OH).sub.2 wherein Ar represents a single-ring aromatic moiety, Q represents at least one electron withdrawing group substituted on the Ar moiety selected from sulfonic acid, sulfonic acid salts and nitro group, and the hydroxyl (OH) groups are substituted on the Ar moiety in paired position with respect to each other.
Claim 3
Dependent Claim
22 words
The method of claim 1 wherein the aqueous system further contains at least one water treatment agent other than said dihydroxyaromatic compound.
Claim 4
Dependent Claim
13 words
The method of claim 1 wherein Q represents sulfonic acid or salts thereof.
Claim 5
Dependent Claim
22 words
The method of claim 3 wherein the aqueous system further contains at least one water treatment agent other than said dihydroxyaromatic compound.
Claim 6
Dependent Claim
11 words
The method of claim 1 wherein Q represents a nitro group.
Claim 7
Dependent Claim
22 words
The method of claim 5 wherein the aqueous system further contains at least one water treatment agent other than said dihydroxyaromatic compound.
Claim 8
Dependent Claim
25 words
The method of claim 1 wherein the dihydroxylaromatic compound is maintained at a concentration of from about 1 to 1000 ppm in the aqueous solution.
Claim 9
Dependent Claim
11 words
The method of claim 7 wherein Q represents a nitro group.
Claim 10
Dependent Claim
13 words
The method of claim 7 wherein Q represents sulfonic acid or salts thereof.
Claim 11
Independent Claim
117 words
A method of inhibiting corrosion of iron based metal which is in contact with an aqueous system comprising maintaining in the aqueous system at least one corrosion inhibiting agent selected from phosphates, organophosphates, chromates, molybdates, azoles and zinc in combination with at least one dihydroxyaromatic compound represented by the formula Q Ar (OH.sub.2) wherein Ar represents a single-ring aromatic moiety, Q represents at least one electron withdrawing group substituted on the Ar moiety selected from sulfonic acid, sulfonic acid salts and nitro group, and the hydroxyl groups are substituted on the Ar moiety in paired position with respect to each other; said inhibiting agent and dihydroxyaromatic compound are present in a weight ratio of 100:1 to 1:100.
Claim 12
Independent Claim
117 words
A method of inhibiting corrosion of iron based metal which is in contact with an aqueous system comprising maintaining in the aqueous system at least one corrosion inhibiting agent selected from phosphates, organophosphates, chromates, molybdates, azoles and zinc in combination with at least one dihydroxyaromatic compound represented by the formula Q Ar (OH.sub.2) wherein Ar represents a single-ring aromatic moiety, Q represents at least one electron withdrawing group substituted on the Ar moiety selected from sulfonic acid, sulfonic acid salts and nitro group, and the hydroxyl groups are substituted on the Ar moiety in paired position with respect to each other; said inhibiting agent and dihydroxyaromatic compound are present in a weight ratio of 100:1 to 1:100.
Claim 13
Dependent Claim
22 words
The method of claim 10 wherein the dihydroxyaromatic compound is present in from 0.1 to 50,000 ppm concentration in the aqueous system.
Claim 14
Dependent Claim
26 words
The method of claim 10 wherein the aqueous system further contains at least one water treatment agent other than said dihydroxyaromatic and said corrosion inhibiting agent.
Claim 15
Dependent Claim
14 words
The method of claim 10 wherein Q represents sulfonic acid or its metal salts.
Claim 16
Dependent Claim
10 words
The method of claim 10 wherein Q represents nitro group.
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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) | 1993-06-18 | 1993-12-18 | 1994-06-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-06-18 | 1997-12-18 | 1998-06-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-06-18 | 2001-12-18 | 2002-06-19 | $7700.00 | Window Closed / Lapsed |