Azeotrope-like compositions of difluoromethane and chlorine
US6099694A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Mar 23, 1998 |
| Grant date | Aug 8, 2000 |
| Priority date | — |
| Expiry date | Mar 23, 2018 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC07C19/08
- WIPO fieldOrganic fine chemistry
- WIPO sectorChemistry
Abstract
The invention relates to an improvement in a process in which chlorine and difluoromethane are present in a distillation column, for example, a fluorination reaction. By controlling the chlorine feed such that the concentration of chlorine relative to difluoromethane in the distillation column is maintained below about 22 weight percent (the flammability threshold for chlorine in a mixture of difluoromethane and chlorine), formation of a flammable difluoromethane/chlorine mixture may be minimized or avoided. The invention is particularly useful in a process for the preparation of difluoromethane wherein at least one distillation column separates difluoromethane from unreacted starting materials such as methylene chloride, hydrogen fluoride and monochloromonofluoromethane.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.