US4174377A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Formation of cyanate compounds
Assignee: AT&T Inc
•
Filing: 1978-05-25
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Granted: 1979-11-13
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Expires: 1998-05-25
Abstract
Abstract The use of a reaction mixture of carbon monoxide, an oxide of nitrogen such as nitric oxide, and a source of hydrogen when passed over a hydrogenation catalyst produces cyanate compounds, e.g., ammonium cyanate and isocyanic acid. The reaction conditions chosen determine the relative amounts of the various cyanate compounds to be formed. When the formation of ammonium cyanate is desired, the addition of ammonia to the reaction mixture reduces the amount of nitric oxide reactant necessary, while enhancing the efficiency of ammonium cyanate production. When a palladium or iridium catalyst is used, the production of isocyanic acid is favored.
Inventors
- 👤 Lee E. Trimble
- 👤 Rudolf J. H. Voorhoeve
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 20:38
CPC Classifications
C; C01; C01C; C01C3/00; C01C3/14
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
54 words
A process for producing isocyanic acid comprising the steps of (1) contacting a hydrogenation catalyst with a reaction mixture comprising a nitrogen oxide, CO, and a source of hydrogen under reaction conditions which avoid the substantial formation of collectible ammonia from said reaction mixture and (2) removing said isocyanic acid from the reactant flow.
Claim 2
Dependent Claim
54 words
A process for producing isocyanic acid comprising the steps of (1) contacting a hydrogenation catalyst with a reaction mixture comprising a nitrogen oxide, CO, and a source of hydrogen under reaction conditions which avoid the substantial formation of collectible ammonia from said reaction mixture and (2) removing said isocyanic acid from the reactant flow.
Claim 3
Dependent Claim
37 words
The process of claim 1 wherein said reaction condition is the use of said hydrogenation catalyst containing a noble metal chosen from the group consisting of palladium and iridium, and wherein said cyanate compound is isocyanic acid.
Claim 4
Dependent Claim
22 words
The process of claim 2 wherein said hydrogenation catalyst is maintained at a temperature in the range 200 to 450 degrees C.
Claim 5
Dependent Claim
19 words
The process of claim 3 wherein said hydrogenation catalyst is maintained in the range 250 to 375 degrees C.
Claim 6
Dependent Claim
23 words
The process of claim 2 wherein said source of hydrogen is chosen from the group consisting of H 2 and H 2 O.
Claim 7
Dependent Claim
16 words
The process of claim 2 wherein said hydrogenation catalyst is reduced before contacting said reaction mixture.
Claim 8
Dependent Claim
25 words
The process of claim 2 wherein the flow rate of said reactant mixture is in the range 10 to 1000 l/hr. per m 2 .
Claim 9
Dependent Claim
15 words
The process of claim 2 wherein SO 2 is periodically added to said reaction mixture.
Claim 10
Dependent Claim
57 words
A process for producing ammonium cyanate comprising the steps of (1) contacting a hydrogenation catalyst with a reaction mixture comprising a nitrogen oxide, CO, a source of hydrogen, and ammonia under reaction conditions which avoid the substantial in situ formation of ammonia entities from said reaction mixture and (2) removing said ammonium cyanate from the reactant flow.
Claim 11
Dependent Claim
57 words
A process for producing ammonium cyanate comprising the steps of (1) contacting a hydrogenation catalyst with a reaction mixture comprising a nitrogen oxide, CO, a source of hydrogen, and ammonia under reaction conditions which avoid the substantial in situ formation of ammonia entities from said reaction mixture and (2) removing said ammonium cyanate from the reactant flow.
Claim 12
Dependent Claim
29 words
The process of claim 1 wherein the ratio of said added NH 3 to said nitrogen oxide in said reaction mixture is in the range of 0.01 to 5.0.
Claim 13
Dependent Claim
20 words
The process of claim 10 wherein said NH 3 to NO x ratio is in the range 0.5 to 1.5.
Claim 14
Dependent Claim
22 words
The process of claim 1 wherein said hydrogenation catalyst is maintained at a temperature in the range 200 to 600 degrees C.
Claim 15
Dependent Claim
22 words
The process of claim 1 wherein said hydrogenation catalyst is maintained at a temperature in the range 300 to 400 degrees C.
Claim 16
Dependent Claim
54 words
The process of claim 1 wherein said hydrogenation catalyst contains a catalyst chosen from the group consisting of (1) platinum, (2) palladium, (3) rhodium, (4)iridium, (5) the alloys of platinum, palladium, iridium and rhodium with each other and with metals chosen from the group consisting of Cu, Ag, and Au, and (6) Cu-Ni alloys.
References Cited (Backward Citations)
US1083703A
Cited
US3425803A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1982-11-12 | 1983-05-14 | 1983-11-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1986-11-12 | 1987-05-14 | 1987-11-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1990-11-12 | 1991-05-14 | 1991-11-13 | $7700.00 | Window Closed / Lapsed |