Processes for geometric isomerization of halogenated olefins
US7563936B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Oct 27, 2006 |
| Grant date | Jul 21, 2009 |
| Priority date | — |
| Expiry date | May 8, 2027 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC07C17/358
- WIPO fieldOrganic fine chemistry
- WIPO sectorChemistry
Abstract
Disclosed are processes for the conversion of isomerizable halogenated C2-C6 olefins from one geometric form to a more preferred geometric form. Preferred process aspects involve converting C2-C6 olefin in a cis-form to a trans-form under conditions effective to convert at least about 50 percent, and even more preferably at least about 70 percent, of the cis-form compound to the trans-form compound. In preferred embodiments the C2-C6 olefin comprises tetrafluoropropene, with cis-1,3,3,3 tetrafluoropropene (cis-HFO-1234ze) being converted, preferably at high conversion rates and high selectivity, to trans-1,3,3,3 tetrafluoropropene (trans-HFO-1234ze). In preferred embodiments the conditions effective to achieve the desired high levels of conversion and selectivity include exposing the feed to a metal based catalyst selected from the group consisting of halogentated metal oxides, Lewis acid metal halides, zero-valent metals, and combinations of these, preferably under reaction conditions, including reaction temperature and residence time, effective to convert at least about 5% of the cis-form of the compound to other compounds and to further achieve a selectivity to the trans-form of…
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