Patent US3887488A successfully refreshed from Google Patents.
US3887488A
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Inhibition of corrosion in sulfuric acid solutions
Assignee: Celanese Corp
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Filing: 1974-06-26
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Granted: 1975-06-03
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Expires: 1994-06-26
Abstract
Abstract The corrosion of metal surfaces by aqueous sulfuric acid is inhibited by incorporating into the latter a phosphorus compound having a phosphorus atom linked to an unshared oxygen atom. The phosphorus compound, e.g., orthophosphoric acid, is used in amounts ranging from 1 to 10,000 p.p.m. based on the weight of the aqueous sulfuric acid.
Inventors
- 👤 Robert H Scott
- 👤 Dan L Gaulding
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 19:21
CPC Classifications
C; C23; C23F; C23F11/00; C23F11/04
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
93 words
A method for inhibiting the corrosivity of aqueous sulfuric acid solutions towards metals, said method comprising incorporating into an aqueous sulfuric acid solution, which has a pH of between 0.01 to about 3.0, an amount ranging from 1 to 10, 000 ppm of a corrosion inhibitor consisting essentially of a phosphorus compound having at least one phosphorus atom linked to an unshared oxygen atom and selected from the group consisting of oxy acids of phosphorus, salts of the oxy acids of phosphorus, esters of the oxy acids of phosphorus and oxides of phosphorus.
Claim 2
Independent Claim
93 words
A method for inhibiting the corrosivity of aqueous sulfuric acid solutions towards metals, said method comprising incorporating into an aqueous sulfuric acid solution, which has a pH of between 0.01 to about 3.0, an amount ranging from 1 to 10, 000 ppm of a corrosion inhibitor consisting essentially of a phosphorus compound having at least one phosphorus atom linked to an unshared oxygen atom and selected from the group consisting of oxy acids of phosphorus, salts of the oxy acids of phosphorus, esters of the oxy acids of phosphorus and oxides of phosphorus.
Claim 3
Independent Claim
90 words
A METHOD FOR INHABITING THE CORROSIVITY OF AQUEOUS SULFURIC ACID SOLUTIONS TOWARDS METALS, SAID METHOD COMPRISING INCORPORATING INTO AN AQUEOUS SULFURIC ACID SOLUTION, WHICH HAS A PH OF BETWEEN 0.01 TO ABOUT 3.0, AN AMOUNT RANGING FROM 1 TO 10,000 PPM OF ACORROSION INHABITOR CONSISTING ESSENTIALLY OF A PHOSPHORUS COMPOUND HAVING AT LEAST ONE PHOSPHORUS ATOM LINKED TO AN UNSHARED OXYGEN ATOM AND SELECTED FROM THE GROUP CONSISTING OF OXY ACIDS OF PHOSHPORUS, SALTS OF THE OXY ACID PHOSPHORUS, ESTERS OF THE OXY ACIDS OF PHOSPHORUS AND OXIDE OF PHOSPHORUS.
Claim 4
Independent Claim
90 words
A METHOD FOR INHABITING THE CORROSIVITY OF AQUEOUS SULFURIC ACID SOLUTIONS TOWARDS METALS, SAID METHOD COMPRISING INCORPORATING INTO AN AQUEOUS SULFURIC ACID SOLUTION, WHICH HAS A PH OF BETWEEN 0.01 TO ABOUT 3.0, AN AMOUNT RANGING FROM 1 TO 10,000 PPM OF ACORROSION INHABITOR CONSISTING ESSENTIALLY OF A PHOSPHORUS COMPOUND HAVING AT LEAST ONE PHOSPHORUS ATOM LINKED TO AN UNSHARED OXYGEN ATOM AND SELECTED FROM THE GROUP CONSISTING OF OXY ACIDS OF PHOSHPORUS, SALTS OF THE OXY ACID PHOSPHORUS, ESTERS OF THE OXY ACIDS OF PHOSPHORUS AND OXIDE OF PHOSPHORUS.
Claim 5
Independent Claim
115 words
A METHOD FOR INHABITING THE CORROSIVITY OF AQUEOUS SULFURIC ACID SOLUTIONSTOWARD METALS, SAID METHOD COMPRISING INCOR HAS APH OF BETWEEN ABOUT 0.5 AND 3.0, AN AMOUNT RANGING FROM 1 TO 10,000 PPM OF A CORROSION INHABITOR CONSISTING ESSENTIALLY OF A PHOSPHORUS COMPOUND HAVNG AT LEAST ONE PHOSPHOROUS ATOM LINKED TO AN UNSHARED OXGEN ATOM AND SELECTED FROM THE GROUP CONSISTING OF OXY ACIDS OF PHOSPHOROUS, SALTS OF THE OXY ACIDSOF PHOSPHORUS, ESTERS OF THE OXY ACIDS OF PHOSPHOROUS AND OXIDES OF PHOSPHORUS. 10 AN AQUEOUS SULFURIC SOLUTION WTH A PH OF BETWEEN ABOUT 0.5 AND 3.0 HAVING INCORPORATED THEREIN A CORROSION INHIBITOR CONSISTING OF ORTHOPHOSPORIC ACID IN A CONCENTRATION OF ABOUT 1 TO 10,000 PPM.
Claim 6
Independent Claim
115 words
A METHOD FOR INHABITING THE CORROSIVITY OF AQUEOUS SULFURIC ACID SOLUTIONSTOWARD METALS, SAID METHOD COMPRISING INCOR HAS APH OF BETWEEN ABOUT 0.5 AND 3.0, AN AMOUNT RANGING FROM 1 TO 10,000 PPM OF A CORROSION INHABITOR CONSISTING ESSENTIALLY OF A PHOSPHORUS COMPOUND HAVNG AT LEAST ONE PHOSPHOROUS ATOM LINKED TO AN UNSHARED OXGEN ATOM AND SELECTED FROM THE GROUP CONSISTING OF OXY ACIDS OF PHOSPHOROUS, SALTS OF THE OXY ACIDSOF PHOSPHORUS, ESTERS OF THE OXY ACIDS OF PHOSPHOROUS AND OXIDES OF PHOSPHORUS. 10 AN AQUEOUS SULFURIC SOLUTION WTH A PH OF BETWEEN ABOUT 0.5 AND 3.0 HAVING INCORPORATED THEREIN A CORROSION INHIBITOR CONSISTING OF ORTHOPHOSPORIC ACID IN A CONCENTRATION OF ABOUT 1 TO 10,000 PPM.
Claim 7
Independent Claim
93 words
A method for inhibiting the corrosivity of aqueous sulfuric acid solutions toward metals, said method comprising incorporating into an aqueous sulfuric acid solution, which has a pH of between about 0.5 and 3.0, an amount ranging from 1 to 10, 000 ppm of a corrosion inhibitor consisting essentially of a phosphorus compound having at least one phosphorus atom linked to an unshared oxygen atom and selected from the group consisting of oxy acids of phosphorus, salts of the oxy acids of phosphorus, esters of the oxy acids of phosphorus and oxides of phosphorus.
Claim 8
Independent Claim
93 words
A method for inhibiting the corrosivity of aqueous sulfuric acid solutions toward metals, said method comprising incorporating into an aqueous sulfuric acid solution, which has a pH of between about 0.5 and 3.0, an amount ranging from 1 to 10, 000 ppm of a corrosion inhibitor consisting essentially of a phosphorus compound having at least one phosphorus atom linked to an unshared oxygen atom and selected from the group consisting of oxy acids of phosphorus, salts of the oxy acids of phosphorus, esters of the oxy acids of phosphorus and oxides of phosphorus.
Claim 9
Dependent Claim
15 words
The method of claim 2 wherein the phosphorus compound is orthophosphoric acid or pyrophosphoric acid.
Claim 10
Dependent Claim
25 words
The method of claim 2 wherein the phosphorus compound is an alkali metal salt of orthophosphoric acid or an alkali metal salt of pyrophosphoric acid.
Claim 11
Dependent Claim
30 words
The method of claim 4 wherein the alkali metal salt of orthophosphoric acid is monopotassium orthophosphate or trisodium orthophosphate and the alkali metal salt of pyrophosphoric acid is tetrasodium pyrophosphate.
Claim 12
Dependent Claim
25 words
The method of claim 2 wherein the phosphorus compound is an alkali metal salt of orthophosphorous acid or an alkali metal salt of hypophosphorous acid.
Claim 13
Dependent Claim
27 words
The method of claim 6 wherein the alkali metal salt of orthophosphorous acid is monosodium orthophosphite and the alkali metal salt of hypophosphorous acid is sodium hypophosphite.
Claim 14
Dependent Claim
32 words
The method of claim 2 wherein said metal being inhibited is stainless steel and said phosphorus compound is orthophosphoric acid which is present in amounts of from about 100 to 5,000 ppm.
Claim 15
Dependent Claim
17 words
The method of claim 2 wherein said method is for the inhibition of corrosion of stainless steel.
Claim 16
Dependent Claim
33 words
An aqueous sulfuric acid solution with a pH of between about 0.5 and 3.0 having incorporated therein a corrosion inhibitor consisting of orthophosphoric acid in a concentration of about 1 to 10,000 ppm.
Claim 17
Dependent Claim
33 words
An aqueous sulfuric acid solution with a pH of between about 0.5 and 3.0 having incorporated therein a corrosion inhibitor consisting of orthophosphoric acid in a concentration of about 1 to 10,000 ppm.
Claim 18
Dependent Claim
20 words
The solution of claim 9 wherein the orthophosphoric acid is present in amounts of from about 100 to 5,000 ppm.
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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) | 1978-06-02 | 1978-12-02 | 1979-06-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-06-02 | 1982-12-02 | 1983-06-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-06-02 | 1986-12-02 | 1987-06-03 | $7700.00 | Window Closed / Lapsed |