Process for production of 1,2,2,2-tetrafluoroethyl difluoromethyl ether (desflurane)
The present invention provides a continuous process for the production of 1,2,2,2-tetrafluoroethyl difluoromethyl ether (desflurane) which comprises feeding continuously optimum molar quantities of 1-chloro-2,2,2-trifluoroethyl difluoromethyl ether (CF 3 CHClOCHF 2 , Isoflurane) and anhydrous hydrogen fluoride, in a reactor in the vapor phase over a fluorination catalyst system comprising a metal pentahalide absorbed on a supporting substrate at a temperature ranging from 100° C. to 180° C., and separating 1,2,2,2-tetrafluoroethyl difluoromethyl ether (desflurane) continuously from the reactor. The process of the present invention enables continuous removal of desflurane product thereby minimizing co-production of byproducts and resulting in high conversion efficiency and yield of desflurane.
1. A process for the production of 1,2,2,2-tetrafluoroethyl difluoromethyl ether (desflurane), comprising:
passing into a reactor a feed mixture consisting of 1-chloro-2,2,2-trifluoroethyl difluoromethyl ether (isoflurane) and anhydrous hydrogen fluoride in the vapour phase;
the feed mixture being passed over a fluorination catalyst system consisting essentially of a metal pentahalide absorbed on a supporting substrate at a temperature ranging from 100° C. to 180° C;
the process being operated as a continuous process.
2. The process as claimed in claim 1 , wherein the said feed mixture consisting of anhydrous hydrogen fluoride (HF) and 1-chloro-2,2,2-trifluoroethyl difluoromethyl ether (isoflurane) has a molar ratio of HF to isoflurane in the range from 0.25:1 to 10:1.
3. The process as claimed in claim 1 , wherein the said feed mixture consisting of anhydrous hydrogen fluoride (HF) and 1- chloro-2,2,2-trifluoroethyl difluoromethyl ether (isoflurane) has a molar ratio of HF to isoflurane in the range from 1:1 to 5:1.
4. The process as claimed in claim 1 , wherein the said feed mixture consisting of anhydrous hydrogen fluoride (HF) and 1-chloro-2,2,2-trifluoroethyl difluoromethyl ether (isoflurane) has a molar ratio of HF to isoflurane in the range from 1.5:1 to 4:1.
5. The process as claimed in claim 1 , wherein said feed mixture is passed over said fluorination catalyst system at a temperature ranging from 120° C. to 150 ° C.
6. The process as claimed in claim 1 , wherein said metal pentahalide is selected from a group consisting of antimony pentachloride, antimony pentafluoride, arsenic pentafluoride, tantalum pentachloride and niobium pentafluoride, or mixtures thereof.
7. The process as claimed in claim 6 , wherein said metal pentahalide is selected from antimony pentachloride, antimony pentafluoride, or mixtures thereof.
8. The process as claimed in claim 1 , wherein the supporting substrate in the fluorination catalyst system is selected from carbon or alumina.
9. The process as claimed in claim 8 , wherein said carbon is an activated carbon.
10. The process as claimed in claim 1 , wherein in the fluorination catalyst system the concentration of said metal pentahalide on the said supporting substrate is 0.5 to 4.0 mmol/g.
11. The process as claimed in claim 10 , wherein the concentration of said metal pentahalide on the said supporting substrate is from 0.5 to 2.5 mmol/g.
12. The process as claimed in claim 10 , wherein the concentration of said metal pentahalide on the said supporting substrate is from 1.0 to 2.0 mmol/g.
13. The process as claimed in claim 1 , wherein passing of said feed mixture in the vapour phase over said fluorination catalyst system is carried out at an atmospheric pressure or an elevated pressure or a reduced pressure within the range from 0.5 to 10 bar.
14. The process as claimed in claim 13 , wherein passing of said feed mixture in the vapour phase over said fluorination catalyst system is carried out at an atmospheric pressure or an elevated pressure or a reduced pressure within the range from 0.8 to 4 bar.