Processes for the manufacture and purification of 1,1,2,2,3,3,4,4-octafluorobutane and by-products
US5817893A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jun 3, 1997 |
| Grant date | Oct 6, 1998 |
| Priority date | — |
| Expiry date | Jun 3, 2017 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY02P20/582
- WIPO fieldOrganic fine chemistry
- WIPO sectorChemistry
Abstract
A process is disclosed for producing 1,12,2,3,3,4,4-octafluorobutane. The process involves chlorination of 2,2,3,3-tetrafluorobutane to form a mixture of chloro-compounds wherein compounds of the formula C.sub.4 H.sub.4 Cl.sub.6-x F.sub.4 (where x is 0 or 1) comprise at least 50 mole % of the mixture of chloro-compounds, followed by hydrofluorination, then hydrogenolysis, and sufficient recycle to provide a selectivity to CHF.sub.2 CF.sub.2 CF.sub.2 CHF.sub.2 of at least about 75% based upon the moles of CH.sub.3 CF.sub.2 CF.sub.2 CH.sub.3 reacted. Also disclosed is a multi-distillation process for the purification of CHF.sub.2 CF.sub.2 CF.sub.2 CHF.sub.2 from a mixture of HF and the compound(s). Also disclosed are certain new halogenated butanes containing fluorine, and a composition which contains HF in combination with an effective amount of CHF.sub.2 CF.sub.2 CF.sub.2 CHF.sub.2 to form an azeotrope or azeotrope-like composition with hydrogen fluoride.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.