Methods for the elimination of cyanides in the dehalogenation of halofluorocarbons
US5602295A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | May 5, 1995 |
| Grant date | Feb 11, 1997 |
| Priority date | — |
| Expiry date | May 5, 2015 |
Classification
- Technology area (CPC A)Human Necessities
- CPC primaryA62D2203/02
- WIPO fieldMachine tools
- WIPO sectorMechanical engineering
Abstract
Ozone depleting fluorocarbon compounds are dehalogenated through more economic reduction reaction with solvated electrons formed from lower equivalents of reactive metals than previously used by reacting the partial reduction products with nitrogen-containing bases, such as ammonia, or alternatively, without any reactive metal by reacting with the base alone. Mixtures of fluorocarbon refrigerants including difficult to separate azeotropes of dichlorodifluoromethane contaminated with chlorodifluoromethane are reclaimed by treating only with weak non-aqueous nitrogen-containing bases to provide essentially chemically pure dichlorodifluoromethane refrigerant suitable for recycling/reuse. Hazardous cyanides which may develop are converted to relatively benign products during the process by introducing a base to convert volatile cyanides to more stable salts which in turn are converted to useful compounds of lesser toxicity.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.