US4668497A
Expired / Lapsed
US
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Process for purifying hydrogen fluoride
Assignee: Stella Chemifa Corp
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Filing: 1985-12-24
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Granted: 1987-05-26
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Expires: 2005-12-24
Abstract
Abstract A process for purifying hydrogen fluroide characterized by adding fluorine to hydrogen fluoride containing at least one element selected from the group consisting of boron, silicon, phosphorus, sulfur, chlorine and arsenic, and/or at least one compound of these elements, reacting the fluorine with said element and/or said compound and distilling the resulting mixture.
Inventors
- 👤 Nobuhiro Miki
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 03:37
CPC Classifications
C; C01; C01B; C01B7/00; C01B7/19; C01B7/191; C01B7/195; C01B7/196
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
50 words
A process for purifying hydrogen fluoride comprising adding fluorine to hydrogen fluoride containing at least one element selected from the group consisting of boron, silicon, chlorine and arsenic, and/or at least one compound of these elements, reacting the fluorine with said element and/or said compound and distilling the resulting mixture.
Claim 2
Dependent Claim
50 words
A process for purifying hydrogen fluoride comprising adding fluorine to hydrogen fluoride containing at least one element selected from the group consisting of boron, silicon, chlorine and arsenic, and/or at least one compound of these elements, reacting the fluorine with said element and/or said compound and distilling the resulting mixture.
Claim 3
Dependent Claim
19 words
A process as defined in claim 1 wherein the distillation is followed by hydrolysis to remove the remaining fluorine.
Claim 4
Dependent Claim
20 words
A process as defined in claim 2 wherein the hydrolysis is conducted while supplying air to the purified hydrogen fluoride.
Claim 5
Dependent Claim
16 words
A process as defined in claim 1 wherein the fluorine is diluted with an inert gas.
Claim 6
Dependent Claim
18 words
A process as defined in claim 1 wherein the fluorine is used as dissolved in an inert liquid.
Claim 7
Dependent Claim
20 words
A process as defined in claim 1 wherein water is added to the purified hudrogen fluoride to obtain hydrofluoric acid.
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) | 1990-05-25 | 1990-11-24 | 1991-05-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-05-25 | 1994-11-24 | 1995-05-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-05-25 | 1998-11-24 | 1999-05-26 | $7700.00 | Window Closed / Lapsed |