Purification of 1,1,1,3,3-pentafluoropropane (R-245fa)
US6077982A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 27, 1998 |
| Grant date | Jun 20, 2000 |
| Priority date | — |
| Expiry date | Jul 27, 2018 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC07C17/395
- WIPO fieldOrganic fine chemistry
- WIPO sectorChemistry
Abstract
In the synthesis of 1,1,1,3,3-pentafluoropropane (R-245fa), a mixture of R-245fa and the impurity 1-chloro-3,3,3-trifluoropropene (R-1233zd) is purified and R-1233zd is removed from the mixture by contacting the mixture with 1-5 mols of chlorine for each mol of R-1233zd in the presence of ultraviolet light having a wavelength between about 300 to 400 nm which provides at least 0.02 watts-hour/kg of the mixture, the R-1233zd being reduced to below 10 wt. ppm or lower, as it is converted to 1,2,2-trichloro-3,3,3-trifluoropropane (R-233) or other propane which contains more chlorine and which has a higher boiling point than R-245fa and can be separated easily from R-245fa, the photochlorination being effected in a manner such that at least about 96 wt. % of the starting amount of R-245fa is maintained in the mixture.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.