US4032621A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Preparation of hydrogen fluoride with low levels of arsenic, iron and sulfite
Assignee: EIDP Inc
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Filing: 1975-11-24
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Granted: 1977-06-28
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Expires: 1995-11-24
Abstract
Abstract A process for preparing pure anhydrous hydrogen fluoride with decreased levels of arsenic, iron and sulfite by treating anhydrous hydrogen fluoride sequentially with an oxidizing agent, and then a heavy metal free reducing agent, distilling the resulting mixture and recovering the pure hydrogen fluoride.
Inventors
- 👤 Geoffrey Walsh Meadows
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 18:53
CPC Classifications
C; C01; C01B; C01B7/00; C01B7/19; C01B7/191
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
127 words
A process for the preparation of pure anhydrous hydrogen fluoride with lower impurities which comprises sequentially contacting anhydrous hydrogen fluoride containing impurities selected from the group consisting of arsenic, iron and sulfite at ambient temperature with (a) more than the stoichiometric amount of an oxidizing agent selected from the group consisting of alkali metal permanganates and alkali metal dichromates to oxidize the impurities to the non-volatile species; (b) at least a stoichiometric amount based on the amount of unreacted oxidizing agent present of a heavy metal free reducing agent selected from the group consisting of alkali metal percarbonates, alkali metal perborates and hydrogen peroxide to reduce the unreacted oxidizing agent; and (c) distilling the resulting mixture and recovering a high purity anhydrous hydrogen fluoride with decreased impurities.
Claim 2
Dependent Claim
127 words
A process for the preparation of pure anhydrous hydrogen fluoride with lower impurities which comprises sequentially contacting anhydrous hydrogen fluoride containing impurities selected from the group consisting of arsenic, iron and sulfite at ambient temperature with (a) more than the stoichiometric amount of an oxidizing agent selected from the group consisting of alkali metal permanganates and alkali metal dichromates to oxidize the impurities to the non-volatile species; (b) at least a stoichiometric amount based on the amount of unreacted oxidizing agent present of a heavy metal free reducing agent selected from the group consisting of alkali metal percarbonates, alkali metal perborates and hydrogen peroxide to reduce the unreacted oxidizing agent; and (c) distilling the resulting mixture and recovering a high purity anhydrous hydrogen fluoride with decreased impurities.
Claim 3
Dependent Claim
12 words
The process of claim 1 wherein the oxidizing agent is potassium permanganate.
Claim 4
Dependent Claim
12 words
The process of claim 1 wherein the oxidizing agent is potassium dichromate.
Claim 5
Dependent Claim
12 words
The process of claim 1 wherein the reducing agent is hydrogen peroxide.
Claim 6
Dependent Claim
12 words
The process of claim 4 wherein the oxidizing agent is potassium permanganate.
Claim 7
Dependent Claim
12 words
The process of claim 4 wherein the oxidizing agent is potassium dichromate.
References Cited (Backward Citations)
US3166379A
Cited
US3687622A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1980-06-27 | 1980-12-27 | 1981-06-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-06-27 | 1984-12-27 | 1985-06-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-06-27 | 1988-12-27 | 1989-06-28 | $7700.00 | Window Closed / Lapsed |