Patent US4083941A successfully refreshed from Google Patents.
US4083941A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Purification of anhydrous hydrogen fluoride
Assignee: EIDP Inc
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Filing: 1977-04-18
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Granted: 1978-04-11
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Expires: 1997-04-18
Abstract
Abstract A process for preparing very high purity anhydrous hydrogen fluoride by contacting anhydrous hydrogen fluoride with at least 2.3% by weight of persulfuric acid based on the anhydrous hydrogen fluoride or at least 0.7% by weight of hydrogen peroxide based on the anhydrous hydrogen fluoride at ambient temperature and either at least 0.6% by weight of methanol based on the anhydrous hydrogen fluoride or at least one mole of sulfuric acid per mole of hydrogen peroxide at a temperature of from 0 DEG to 75 DEG C and distilling the resulting mixture to recover very high purity anhydrous hydrogen fluoride.
Inventors
- 👤 Madhusudan Dattatraya Jayawant
- 👤 Geoffrey Walsh Meadows
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 18:46
CPC Classifications
C; C01; C01B; C01B7/00; C01B7/19; C01B7/191
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
134 words
A process for the preparation of pure anhydrous hydrogen fluoride with reduced arsenic and sulfite impurities consisting essentially of (1) contacting in equipment inert thereto anhydrous hydrogen fluoride having arsenic and sulfite impurities with (a) at least 2.3% by weight of H 2 SO 5 based on the anhydrous hydrogen fluoride or (b) at least 0.7% by weight based on the anhydrous hydrogen fluoride of hydrogen peroxide and either at least 0.6% by weight of methanol based on the anhydrous hydrogen fluoride or at least 1 mole of sulfuric acid per mole of hydrogen peroxide, at a temperature of from 0° to 75° C, (2) distilling the resulting mixture and (3) recovering a high purity anhydrous hydrogen fluoride with arsenic and sulfite impurities of 0.03 ppm or less and 3 ppm or less respectively.
Claim 2
Dependent Claim
134 words
A process for the preparation of pure anhydrous hydrogen fluoride with reduced arsenic and sulfite impurities consisting essentially of (1) contacting in equipment inert thereto anhydrous hydrogen fluoride having arsenic and sulfite impurities with (a) at least 2.3% by weight of H 2 SO 5 based on the anhydrous hydrogen fluoride or (b) at least 0.7% by weight based on the anhydrous hydrogen fluoride of hydrogen peroxide and either at least 0.6% by weight of methanol based on the anhydrous hydrogen fluoride or at least 1 mole of sulfuric acid per mole of hydrogen peroxide, at a temperature of from 0° to 75° C, (2) distilling the resulting mixture and (3) recovering a high purity anhydrous hydrogen fluoride with arsenic and sulfite impurities of 0.03 ppm or less and 3 ppm or less respectively.
Claim 3
Dependent Claim
13 words
The process of claim 1 wherein the temperature is 0° to 20° C.
Claim 4
Dependent Claim
14 words
The process of claim 1 wherein 0.7 to 1.5% of hydrogen peroxide is used.
Claim 5
Dependent Claim
13 words
The process of claim 1 wherein 0.6 to 2% of methanol is used.
Claim 6
Dependent Claim
15 words
The process of claim 1 wherein 1 to 5 moles of sulfuric acid is used.
Claim 7
Dependent Claim
10 words
The process of claim 1 wherein sulfuric acid is used.
Claim 8
Dependent Claim
15 words
The process of claim 6 wherein 1.5 to 5 moles of sulfuric acid is used.
Claim 9
Dependent Claim
12 words
The process of claim 1 wherein hydrogen peroxide and methanol are used.
Claim 10
Dependent Claim
20 words
The process of claim 8 wherein 0.7% to 1.5% of hydrogen peroxide and 0.6% to 2.0% of methanol is used.
Claim 11
Dependent Claim
14 words
The process of claim 9 wherein the temperature is from 0° to 20° C.
Claim 12
Dependent Claim
12 words
The process of claim 1 wherein H 2 SO 5 is used.
Claim 13
Dependent Claim
17 words
The process of claim 11 wherein 2.3% to to 5% of H 2 SO 5 is used.
Claim 14
Dependent Claim
14 words
The process of claim 12 wherein the temperature is from 0° to 20° C.
Claim 15
Dependent Claim
13 words
The process of claim 1 wherein hydrogen peroxide and sulfuric acid are used.
Claim 16
Dependent Claim
22 words
The process of claim 14 wherein 0.7% to 1.5% of hydrogen peroxide and 1 to 5 moles of sulfuric acid are used.
Claim 17
Dependent Claim
14 words
The process of claim 15 wherein the temperature is from 0° to 20° C.
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) | 1981-04-10 | 1981-10-10 | 1982-04-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-04-10 | 1985-10-10 | 1986-04-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-04-10 | 1989-10-10 | 1990-04-11 | $7700.00 | Window Closed / Lapsed |