Patent US4424067A successfully refreshed from Google Patents.
US4424067A
Expired / Lapsed
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Purification of anhydrous hydrogen fluoride
Assignee: Fisher Scientific Co LLC
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Filing: 1982-07-29
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Granted: 1984-01-03
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Expires: 2002-07-29
Abstract
Abstract The arsenic trifluoride content of anhydrous hydrogen fluoride is reduced by diffusion in one or more stages through a non-porous fluoride-resistant film, such as a thin fluoropolymer film.
Inventors
- 👤 Valentin Tarasenko
- 👤 Harold Edelstein
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 22:18
CPC Classifications
C; C01; C01B; C01B7/00; C01B7/19; C01B7/191; C01B7/195; B; B01; B01D; B01D53/00; B01D53/22; B01D53/225; B01D53/226
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
94 words
A method of reducing the arsenic trifluoride impurity level in hydrogen fluoride gas which comprises: (a) introducing on one side of a non-porous polymer film resistant to degradation by fluoride a first gaseous mixture comprising a major proportion of hydrogen fluoride and a minor proportion of arsenic trifluoride, and (b) recovering from the opposite side of said non-porous polymer film a second gaseous mixture which has diffused through said polymer film, said second gaseous mixture containing a greater proportion of hydrogen fluoride and a lesser proportion of arsenic trifluoride than said first gaseous mixture.
Claim 2
Independent Claim
94 words
A method of reducing the arsenic trifluoride impurity level in hydrogen fluoride gas which comprises: (a) introducing on one side of a non-porous polymer film resistant to degradation by fluoride a first gaseous mixture comprising a major proportion of hydrogen fluoride and a minor proportion of arsenic trifluoride, and (b) recovering from the opposite side of said non-porous polymer film a second gaseous mixture which has diffused through said polymer film, said second gaseous mixture containing a greater proportion of hydrogen fluoride and a lesser proportion of arsenic trifluoride than said first gaseous mixture.
Claim 3
Dependent Claim
14 words
The method of claim 1 wherein said non-porous polymer film is a fluoropolymer film.
Claim 4
Dependent Claim
11 words
The method of claim 2 wherein said polymer film is poly(perfluoroethylene-propylene).
Claim 5
Dependent Claim
29 words
The method of claim 1 wherein said second gaseous mixture contains an arsenic trifluoride proportion no more than 50% of the arsenic trifluoride proportion in said first gaseous mixture.
Claim 6
Dependent Claim
29 words
The method of claim 4 wherein said second gaseous mixture contains an arsenic trifluoride proportion no more than 20% of the arsenic trifluoride proportion in said first gaseous mixture.
Claim 7
Dependent Claim
59 words
The method of claim 1 wherein said second gaseous mixture is introduced on one side of a second polymer film resistant to degradation by fluoride; and a third gas mixture, which has diffused through the second polymer film, is recovered containing a greater proportion of hydrogen fluoride and a lesser proportion of arsenic trifluoride than said second gaseous mixture.
Claim 8
Dependent Claim
29 words
The method of claim 6 wherein said third gaseous mixture contains an arsenic trifluoride proportion no more than 10% of the arsenic trifluoride proportion in said first gaseous mixture.
Claim 9
Dependent Claim
19 words
The process of claim 1 wherein said non-porous polymer film has a thickness between about 0.01 and 0.1 mm.
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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) | 1987-01-02 | 1987-07-04 | 1988-01-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-01-02 | 1991-07-04 | 1992-01-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-01-02 | 1995-07-04 | 1996-01-03 | $7700.00 | Window Closed / Lapsed |