US4756899A
Expired / Lapsed
US
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Manufacture of high purity low arsenic anhydrous hydrogen fluoride
Assignee: Honeywell International Inc
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Filing: 1987-02-12
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Granted: 1988-07-12
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Expires: 2007-02-12
Abstract
Abstract A process for manufacturing high purity anhydrous hydrogen fluoride (HF) having low levels of arsenic impurity by contacting anhydrous hydrogen fluoride product, or an intermediate product obtained during the manufacture of HF, with hydrogen peroxide in the presence of a catalyst which comprises effective amounts of molybdenum or an inorganic molybdenum compound and a phosphate compound. The volatile trivalent arsenic impurity in the anhydrous hydrogen fluoride is oxidized to a non-volatile pentavalent arsenic compound and the resultant mixture is distilled to recover high purity anhydrous hydrogen fluoride with reduced levels of arsenic impurity. In one embodiment, an oxidizing agent such as nitric acid or a nitrate salt is added to the reaction mixture to oxidize organic contaminants.
Inventors
- 👤 Theodore J. Jenczewski
- 👤 Robert L. Sturtevant
- 👤 Thomas R. Morgan
- 👤 Barry J. Boghean
- 👤 Donald C. Butt
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 03:19
CPC Classifications
C; C01; C01B; C01B7/00; C01B7/19; C01B7/191; C01B7/195; C01B7/196; C01G; C01G28/00
Claims Analysis
Total Claims: 28
Claim 1
Independent Claim
106 words
A process for manufacturing anhydrous hydrogen fluoride with reduced levels of arsenic impurity from arsenic contaminated anhydrous hydrogen fluoride which comprises: (a) contacting said anhydrous hydrogen fluoride with an effective amount of hydrogen peroxide to oxidize the arsenic impurity in the presence of a catalyst which comprises a catalytic amount of (i) molybdenum or an inorganic molybdenum compound and (ii) a phosphate compound, at a temperature and for a period of time sufficient to oxidize volatile trivalent arsenic impurities in the anhydrous hydrogen fluoride to non-volatile pentavalent arsenic compounds, and (b) distilling the resulting mixture and recovering anhydrous hydrogen fluoride with reduced levels of arsenic impurity.
Claim 2
Dependent Claim
106 words
A process for manufacturing anhydrous hydrogen fluoride with reduced levels of arsenic impurity from arsenic contaminated anhydrous hydrogen fluoride which comprises: (a) contacting said anhydrous hydrogen fluoride with an effective amount of hydrogen peroxide to oxidize the arsenic impurity in the presence of a catalyst which comprises a catalytic amount of (i) molybdenum or an inorganic molybdenum compound and (ii) a phosphate compound, at a temperature and for a period of time sufficient to oxidize volatile trivalent arsenic impurities in the anhydrous hydrogen fluoride to non-volatile pentavalent arsenic compounds, and (b) distilling the resulting mixture and recovering anhydrous hydrogen fluoride with reduced levels of arsenic impurity.
Claim 3
Dependent Claim
32 words
The process of claim 1 in which the arsenic contaminated hydrogen fluoride is free of an amount of organic contaminents which would interfere with the hydrogen peroxide oxidation of said arsenic impurities.
Claim 4
Dependent Claim
31 words
The process of claim 2 wherein more than the stoichiometric amount of hydrogen peroxide is used which is required for oxidation of said trivalent arsenic impurities to said pentavalent arsenic compounds.
Claim 5
Dependent Claim
20 words
The process of claim 3 wherein the anhydrous hydrogen fluoride starting material has a purity of 99.95% HF or better.
Claim 6
Dependent Claim
19 words
The process of claim 3 wherein the hydrogen peroxide is 50% to 70% by weight commercial grade hydrogen peroxide.
Claim 7
Dependent Claim
11 words
The process of claim 3 wherein the catalyst contains ammonium molybdate.
Claim 8
Dependent Claim
11 words
The process of claim 3 wherein the catalyst contains sodium pyrophosphate.
Claim 9
Dependent Claim
11 words
The process of claim 3 wherein the catalyst contains phosphoric acid.
Claim 10
Dependent Claim
14 words
The process of claim 3 wherein the catalyst comprises ammonium molybdate and sodium pyrophosphate.
Claim 11
Dependent Claim
14 words
The process of claim 3 wherein the catalyst comprises ammonium molybdate and phosphoric acid.
Claim 12
Dependent Claim
20 words
The process of claim 3 wherein the amount of hydrogen peroxide used is at least 3 times the stoichiometric amount.
Claim 13
Dependent Claim
21 words
The process of claim 3 wherein the reaction is carried out at a temperature in the range of about 15°-75° C.
Claim 14
Dependent Claim
45 words
The process of claim 3 wherein the amount of the molybdenum component in the catalyst is at least about 3.7 ppm based on 100% HF and the amount of the phosphate component in the catalyst is at least about 3.5 ppm based on 100% HF.
Claim 15
Dependent Claim
32 words
The process of claim 3 wherein about the minimum amount of one of the catalyst components is employed and the other catalyst component is present in at least 3-4 times such amount.
Claim 16
Dependent Claim
41 words
The process of claim 9 wherein the amount of ammonium molybdate in the catalyst is between about 15-40 ppm based on 100% HF and the amount of sodium pyrophosphate in the catalyst is between about 25-50 ppm based on 100% HF.
Claim 17
Dependent Claim
66 words
The process of claim 9 wherein the amount of hydrogen peroxide is at least 3 times the stoichiometric amount, the reaction is carried out at a temperature in the range of about 15°-75° C., the amount of the ammonium molybdate is between about 15-40 ppm based on 100% HF and the amount of the sodium pyrophosphate component is between about 25-50 ppm based on 100% HF.
Claim 18
Dependent Claim
65 words
The process of claim 10 wherein the amount of hydrogen peroxide is at least 3 times the stoichiometric amount, the reaction is carried out at a temperature in the range of about 15°-75° C., the amount of the ammonium molybdate is between about 15-40 ppm based on 100% HF and the amount of the phosphoric acid is between about 100-400 ppm based on 100% HF.
Claim 19
Dependent Claim
123 words
A process for manufacturing anhydrous hydrogen flouride with reduced levels of arsenic impurity from arsenic and organic material contaminated anhydrous hydrogen fluoride which comprises contacting said anhydrous hydrogen fluoride with: (a) an effective amount of hydrogen peroxide to oxidize the arsenic impurity, in the presence of a catalyst which comprises a catalytic amount of (i) molybdenum or an inorganic molybdenum compound and (ii) a phosphate compound, and (b) an effective amount of an oxidizing agent to oxidize the organic material present, at a temperature and for a period of time sufficient to oxidize volatile trivalent arsenic impurities in the anhydrous hydrogen flouride to non-volatile pentavalent arsenic compounds, and distilling the resulting mixture and recovering anhydrous hydrogen fluoride with reduced levels of arsenic impurity.
Claim 20
Dependent Claim
123 words
A process for manufacturing anhydrous hydrogen flouride with reduced levels of arsenic impurity from arsenic and organic material contaminated anhydrous hydrogen fluoride which comprises contacting said anhydrous hydrogen fluoride with: (a) an effective amount of hydrogen peroxide to oxidize the arsenic impurity, in the presence of a catalyst which comprises a catalytic amount of (i) molybdenum or an inorganic molybdenum compound and (ii) a phosphate compound, and (b) an effective amount of an oxidizing agent to oxidize the organic material present, at a temperature and for a period of time sufficient to oxidize volatile trivalent arsenic impurities in the anhydrous hydrogen flouride to non-volatile pentavalent arsenic compounds, and distilling the resulting mixture and recovering anhydrous hydrogen fluoride with reduced levels of arsenic impurity.
Claim 21
Dependent Claim
16 words
The process of claim 18 wherein the oxidizing agent is nitric acid or a salt thereof.
Claim 22
Dependent Claim
12 words
The process of claim 19 wherein the oxidizing agent is nitric acid.
Claim 23
Dependent Claim
15 words
The process of claim 19 wherein the oxidizing agent is a salt of nitric acid.
Claim 24
Dependent Claim
12 words
The process of claim 21 wherein the oxidizing agent is sodium nitrate.
Claim 25
Dependent Claim
32 words
The process of claim 1 wherein the inorganic molybdenum compound is selected from the group consisting of a mono- or poly-alkali metal molybdate, a molybdenum oxide or a mono- or poly-ammonium molybdate.
Claim 26
Dependent Claim
13 words
The process of claim 1 wherein the phosphate compound is an phosphate compound.
Claim 27
Dependent Claim
29 words
The process of claim 24 wherein the phosphate compound is selected from the group consisting of phosphoric acid, mono- and poly-alkali metal phosphates and the mono- and poly-ammonium phosphates.
Claim 28
Dependent Claim
31 words
The process of claim 25 wherein the molybdenum compound is selected from the group consisting of a mono- or poly-alkali metal molybdate, a molybdenum oxide or a mono- or poly-ammonium molybdate.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
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| 3.5 Years (Year 4) | 1991-07-12 | 1992-01-11 | 1992-07-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-07-12 | 1996-01-11 | 1996-07-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-07-12 | 2000-01-11 | 2000-07-12 | $7700.00 | Window Closed / Lapsed |