US3764543A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Sulfonium compound as a corrosion inhibitor in aqueous acid
Assignee: Dow Chemical Co
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Filing: 1971-02-23
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Granted: 1973-10-09
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Expires: 1991-02-23
Abstract
Abstract Alkylbenzyldialkysulfonium salts are discovered to be useful corrosion inhibitors in aqueous acid solutions. Said sulfonium salts have the formula WHEREIN N IS 1 OR 2; R1 is an alkyl radical with the aggregate carbon content of R1 being from 6 to about 24 carbon atoms; R2 and R3 are alkyl radicals and X is an anion. The novel inhibitors are useful at very low concentrations even in the presence of ferric ions. E.g., an aqueous solution of ethylenediaminetetracetic acid as the ammonium salt at pH 5 and initially 3 X 10 4M. in p-dodecylbenzyldimethylsulfonium chloride is illustrative of the inhibited solutions disclosed.
Inventors
- 👤 W Frenier
- 👤 W Settineri
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 07:29
CPC Classifications
C; C23; C23G; C23G1/00; C23G1/02; C23G1/04; C23G1/06; C23G1/065; C11; C11D; C11D7/00; C11D7/22; C11D7/34
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
10 words
The composition defined by claim 1 wherein n is 1.
Claim 2
Dependent Claim
16 words
The composition defined by claim 2 wherein R1 is a para substituent on the aromatic ring.
Claim 3
Dependent Claim
20 words
The composition defined by claim 1 wherein each R1 is an alkyl radical of from 8 to 18 carbon atoms.
Claim 4
Dependent Claim
21 words
The composition defined by claim 1 wherein R2 and R3 are independently alkyl radicals of from 1 to 4 carbon atoms.
Claim 5
Dependent Claim
38 words
The composition defined by claim 1 wherein n is 1, R1 is an alkyl radical of from 8 to 18 carbon atoms and R2 and R3 are each independently alkyl radicals of from 1 to 4 carbon atoms.
Claim 6
Dependent Claim
25 words
The composition defined by claim 1 wherein said acid solution is an aqueous solution of a non-oxidizing inorganic acid or a mixture of such acids.
Claim 7
Dependent Claim
25 words
The composition defined by claim 1 wherein said acid solution is an aqueous solution of an organic carboxylic or polycarboxylic acid or a mixture thereof.
Claim 8
Dependent Claim
30 words
The composition defined by claim 1 wherein said acid solution is an aqueous solution of a polyaminepolycarboxylic acid or an ammonium-, amine, or alkali metal salt thereof, or mixtures thereof.
Claim 9
Dependent Claim
34 words
The composition defined by claiM 1 wherein said acid solution is an aqueous solution of at least one of HCl, H2SO4, ethylenediaminetetracetic acid (EDTA) or the ammonium-, amine- or alkali metal salt of EDTA.
Claim 10
Dependent Claim
29 words
The composition defined by claim 1 wherein n is 1; R1 is p-dodecyl; and R2 and R3 are each independently alkyl radicals of from 1 to 4 carbon atoms.
Claim 11
Dependent Claim
38 words
In the process of treating ferrous metal surfaces to remove iron oxide encrustations by treating said metal surface with an aqueous acid cleaning solution, the improvement of using the composition defined by claim 1 as said cleaning solution.
Claim 12
Dependent Claim
44 words
The composition defined by claim 10 wherein said acid solution is an aqueous solution of at least one of EDTA and an ammonium-, amine- or alkali metal salt of EDTA and wherein said solution is buffered to a pH of from 2 to 5.
Claim 13
Dependent Claim
38 words
The composition defined by claim 13 wherein n is 1; R1 is an alkyl radical of from 8 to 18 carbon atoms; and R2 and R3 are each independently alkyl radicals of from 1 to 4 carbon atoms.
Claim 14
Dependent Claim
54 words
A process of inhibiting acid-induced and ferric ion-induced corrosion of metal surfaces in contact with an aqueous acid solution of at least one non-oxidizing inorganic acid or organic acid or mixtures thereof, the process comprising incorporating in said acid solution a small but corrosion-inhibiting amount of at least one sulfonium salt of the formula
Claim 15
Dependent Claim
38 words
The process defined by claim 15 wherein n is 1; R1 is an alkyl radical of from 8 to 18 carbon atoms; and R2 and R3 are each independently alkyl radicals of from 1 to 4 carbon atoms.
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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) | 1976-10-08 | 1977-04-09 | 1977-10-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-10-08 | 1981-04-09 | 1981-10-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-10-08 | 1985-04-09 | 1985-10-09 | $7700.00 | Window Closed / Lapsed |