Production of dihalomethanes containing fluorine and azeotropes of dihalomethanes containing chlorine with HF
US6274781A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Nov 1, 1993 |
| Grant date | Aug 14, 2001 |
| Priority date | — |
| Expiry date | Nov 1, 2013 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC07C17/206
- WIPO fieldOrganic fine chemistry
- WIPO sectorChemistry
Abstract
A process for producing difluoromethane is disclosed which includes the step of contacting a gaseous mixture containing CH.sub.2 Cl.sub.2 and hydrogen fluoride with a catalyst containing a catalytically effective amount of trivalent chromium supported on a carbon having an ash content of less than 0.5 percent by weight, at a temperature of from about 180 .degree. C. to about 375.degree. C. The catalyst and temperature conditions of this process allow the concurrent reaction CCl.sub.3 CF.sub.3 with HF to form CCl.sub.2 FCF.sub.3. CH.sub.2 ClF and unreacted CH.sub.2 Cl.sub.2, each of which may be recovered as an azeotrope with HF, may be recycled.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.