Process for the preparation of hexafluoropropene
AssigneeHoechst Aktiengesellschaft
InventorsReinhold Freudenreich, Ingolf Mielke, Karl Rettenbeck, Thomas Schottle
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Abstract
A process for the preparation of hexafluoropropene by thermal cleavage of chlorotetrafluoroethane and/or chlorohexafluoropropane or a mixture of chlorotetrafluoroethane and perfluorocyclobutane at 600.degree. to 1,000.degree. C. and under a pressure of 1 to 1,000 kPa is described. The thermal cleavage is carried out in the presence of at least 0.05 mole of tetrafluoroethylene per mole of chlorotetrafluoroethane and/or chlorohexafluoropropane or mixture of chlorotetrafluoroethane and perfluorocyclobutane employed. By means of this process hexafluoropropene is obtained for a small extra expenditure on apparatus at a good selectivity and in an improved space-time yield.
Claims19
A process for the preparation of hexafluoropropene by thermal cleavage of a mixture consisting of chlorotetrafluoroethane and perfluorocyclobutane and between 0.5 and 20 mole of tetrafluoroethylene per mole of combined chlorotetrafluoroethane and perfluorocyclobutane at a temperature of from 600.degree. C. to 1,000.degree. C. under a pressure of from 1 kPa to 1,000 kPa.
A process for the preparation of hexafluoropropene by thermal cleavage of a reaction mixture consisting of:
- a) a mixture of chlorotetrafluoroethane and perfluorocyclobutane in a molar ratio of 1:10 to 10:1;
- b) 0.5 to 20 moles, based on moles of a), of tetrafluoroethylene;
- and
- c) 0.01 to 20 moles, based on combined moles of a) and b), of an inert gas which does not undergo chemical reaction,
- comprising reacting the mixture at a temperature of 700.degree.-900.degree. C. under a pressure of from 1 kPa to 1,000 kPa.
A process for the preparation of hexafluoropropene by thermal cleavage of a mixture consisting essentially of chlorotetrafluoroethane, perfluorocyclobutane, and 0.5 to 20 moles of tetrafluoroethylene per mole of combined chlorotetrafluoroethane and perfluorocyclobutane, at a temperature of from 600.degree. C. to 1,000.degree. C. under a pressure of 1 kPa to 1,000 kPa.
Dependencies are inferred from the claim text.