Process for preparing 1,1,1-trifluoro-2-chloroethane and/or 1,1,1,2-tetrafluoroethane
US5426251A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 21, 1993 |
| Grant date | Jun 20, 1995 |
| Priority date | — |
| Expiry date | Jul 21, 2013 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC07C17/383
- WIPO fieldOrganic fine chemistry
- WIPO sectorChemistry
Abstract
A process for preparing 1,1,1-trifluoro-2-chloroethane and/or 1,1,1,2-tetrafluoroethane, comprising the steps of reacting trichloroethylene and/or 1,1,1-trifluoro-2-chloroethane with hydrogen fluoride in the presence of a fluorinating catalyst in a gas pase, separating 1,1,1-trifluoro-2-chloroethane, hydrogen fluoride, and optionally trichloroethylene, from the reaction mixture obtained by the above reaction which contains 1,1,1-trifluoro-2-chloroethane, 1,1,1,2-tetrafluoroethane, hydrogen fluoride, and optionally trichloroethylene, and recycling them to the reaction step above, characterized in that at least a part of the reaction mixture is distilled in a distillation tower, 1,1,1,2-tetrafluoroethane-rich components are discharged from the top of the tower, and a mixture of 1,1,1-trifluoro-2-chloroethane and hydrogen fluoride, and optionally trichloroethylene, is discharged in the form of gas from the middle part of the tower at a temperature which is above the boiling point of the azeotropic mixture of 1,1,1-trifluoro-2-choroethane and hydrogen fluoride and at least 5.degree. C. below the boiling point of anhydrous hydrogen fluoride under the internal pressure in the distillatio…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.