US4895711A
Expired / Lapsed
US
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Preparation of hydroxylammonium salts
Assignee: BASF SE
•
Filing: 1989-03-22
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Granted: 1990-01-23
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Expires: 2009-03-22
Abstract
Abstract Hydroxylammonium salts are prepared by catalytic reduction of nitrogen monoxide with hydrogen in dilute aqueous mineral acids at elevated temperature in the presence of suspended supported platinum catalysts obtainable by precipitating metallic platinum from aqueous solutions of platinum salts onto carriers suspended therein by means of reducing agents in the presence of one or more water-soluble substituted or unsubstituted thioureas.
Inventors
- 👤 Werner Biffar
- 👤 Werner Steigleiter
- 👤 Franz-Josef Weiss
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 21:08
CPC Classifications
C; C01; C01B; C01B21/00; C01B21/082; C01B21/14; C01B21/1409; C01B21/1418; B; B01; B01J; B01J23/00; B01J23/38; B01J23/40; B01J23/42; B01J37/00; B01J37/16
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
93 words
In a process for preparing a hydroxylammonium salt by the catalytic reduction of nitrogen monoxide with hydrogen at an elevated temperature in a dilute aqueous mineral acid, the improvement which comprises: preparing a support platinum catalyst by precipitating metallic platinum from an aqueous solution of a platinum salt onto a carrier suspended in the solution by means of a reducing agent in the presence of one or more water-soluble substituted or unsubstituted thioureas, and carrying out said reduction in the presence of said supported platinum catalyst suspended in the dilute aqueous mineral acid.
Claim 2
Dependent Claim
93 words
In a process for preparing a hydroxylammonium salt by the catalytic reduction of nitrogen monoxide with hydrogen at an elevated temperature in a dilute aqueous mineral acid, the improvement which comprises: preparing a support platinum catalyst by precipitating metallic platinum from an aqueous solution of a platinum salt onto a carrier suspended in the solution by means of a reducing agent in the presence of one or more water-soluble substituted or unsubstituted thioureas, and carrying out said reduction in the presence of said supported platinum catalyst suspended in the dilute aqueous mineral acid.
Claim 3
Dependent Claim
50 words
The process of claim 1, wherein the catalyst is prepared in the presence of a thiourea of the formula I ##STR2## where R 1 , R 2 , R 3 and R 4 may be identical or different and each is hydrogen or alkyl of from 1 to 4 carbon.
Claim 4
Dependent Claim
15 words
The process of claim 1, wherein the catalyst is prepared in the presence of thiourea.
Claim 5
Dependent Claim
24 words
The process of claim 1, wherein per gram-atom of platinum from 0.002 to 2 moles of a water-soluble substituted or unsubstituted thiourea are used.
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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) | 1993-01-22 | 1993-07-24 | 1994-01-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-01-22 | 1997-07-24 | 1998-01-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-01-22 | 2001-07-24 | 2002-01-23 | $7700.00 | Window Closed / Lapsed |