Abstract A process for isolating dinitrogen monoxide from oxidation off-gases formed by the oxidation of a cycloalkanol or a cycloalkanone using nitric acid which off-gases contain dinitrogen monoxide in admixture with nitrogen oxide, nitrogen dioxide, nitrogen, oxygen, carbon dioxide and/or steam which comprises: A. Drying the oxidation off-gas and if necessary removal of nitrogen monoxide, nitrogen dioxide and carbon dioxide. B. Compressing the resultant off-gas from which water has been removed to a pressure in the range of 15 to 300 bars and cooling the same to a temperature in the range of 0° to -88° C.; C. Removing the liquid phase obtained as a result of said compression and cooling; and D. Cooling the resultant gas phase by expansion and passing the same in indirect heat exchange with off-gas which has been prepurified by removal of water content thereof.
Inventors
👤 Hans-Helmut Schwarz
Bibliographic Details
Application Number—
JurisdictionUS
Data Sourcegoogle_patents
Last Synchronized2026-10-26 13:07
CPC Classifications
C; C01; C01B; C01B21/00; C01B21/20; C01B21/22
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
126 words
A process for isolating dinitrogen monoxide from oxidation off-gases formed by the oxidation of a cycloalkanol or a cycloalkanone using nitric acid which off-gases contain dinitrogen monoxide in admixture with nitrogen oxide, nitrogen dioxide, nitrogen, oxygen, carbon-dioxide and/or stream which comprises: A. Drying the oxidation off-gas; B. Compressing the resultant off-gas from which water has been removed to a pressure in the range of 15 to 300 bars and cooling the same to a temperature in the range of 0° to -88° C.; C. Removing the liquid phase obtained as a result of said compression and cooling; and D. Cooling the resultant gas phase by expansion and passing the same in indirect heat exchange with off-gas which has been prepurified by removal of water content thereof.
Claim 2
Dependent Claim
126 words
A process for isolating dinitrogen monoxide from oxidation off-gases formed by the oxidation of a cycloalkanol or a cycloalkanone using nitric acid which off-gases contain dinitrogen monoxide in admixture with nitrogen oxide, nitrogen dioxide, nitrogen, oxygen, carbon-dioxide and/or stream which comprises: A. Drying the oxidation off-gas; B. Compressing the resultant off-gas from which water has been removed to a pressure in the range of 15 to 300 bars and cooling the same to a temperature in the range of 0° to -88° C.; C. Removing the liquid phase obtained as a result of said compression and cooling; and D. Cooling the resultant gas phase by expansion and passing the same in indirect heat exchange with off-gas which has been prepurified by removal of water content thereof.
Claim 3
Dependent Claim
40 words
A process according to claim 1 wherein the off-gas which has been prepurified to remove water is passed through successive zones maintained at 15 to 300 bars pressure and at a temperature in the range from 0° to -88° C.
Claim 4
Dependent Claim
34 words
A process according to claim 2 wherein the gas mixture obtained after removal of the liquid phase is passed through said successive zones in a generally inverse order to the passage of prepurified off-gas.
Claim 5
Dependent Claim
23 words
A process according to claim 1 wherein prior to step B nitrogen monoxide, nitrogen dioxide, and carbon dioxide are removed from the off-gas.