Purification of difluoromethane by extractive distillation
US7371309B2 · kind B2 · utility
7Cited by
6References
27Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Aug 12, 1998 |
| Grant date | May 13, 2008 |
| Priority date | — |
| Expiry date | Aug 12, 2018 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC07C17/386
- WIPO fieldChemical engineering
- WIPO sectorChemistry
Abstract
The present invention provides extractive distillation processes for removing difluoromethane (HFC-32) from a mixture comprising HFC-32 and at least one of chlorodifluoromethane (CFC-12), 1,1,1-trifluoroethane (HFC-143a), chloropentafluoroethane (CFC-115), and pentafluoroethane (HFC-125) using hydrocarbon, chlorocarbon, and oxygen-containing extractive agents.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.