| 摘要 |
A vapor phase synthesis of hexafluoroisobutylene, which comprises contacting in the vapor phase in a catalyst zone, B, of a reactor hexafluoropropylene oxide with a fluorinated catalyst such as fluorinated silica-alumina at a temperature of about 400 DEG -600 DEG C. for a residence time sufficient to form a vapor stream comprising hexafluoroacetone which is thereafter directly contacted in a heating zone of the reactor with a vapor stream comprising a keytone-generating compound such as acetic anhydride at a temperature of about 500 DEG -700 DEG C. for a residence time sufficient to form a stream comprising hexafluoroisobutylene, substantially-free of perfluoroisobutylene and recovering the hexafluoroisobutylene product is disclosed. A direct one reactor vapor phase synthesis of hexafluoroisobutylene which comprises (a) contacting, in the vapor phase, hexafluoropropene with less than a stoichiometric amount of oxygen required to convert substantially all the hexafluoroisopropene into hexafluoropropylene oxide in the presence of a fluorinated catalyst such as fluorinated silica-alumina at a temperature of about 400 DEG -600 DEG C. for a time sufficient to form a vapor stream comprising hexafluoropropylene oxide substantially-free of oxygen; (b) directly contacting said vapor stream, in a catalyst zone, B, containing a fluorinated catalyst which is preferably the same as used in catalyst zone, A, at a temperature of about 400 DEG -650 DEG , preferably about 500 DEG -650 DEG C. for a time sufficient to form a vapor stream comprising hexafluoroacetone; (c) directly contacting the vapor stream comprising hexafluroacetone with a vaporized compound such as acetic anhydride at a temperature of about 500 DEG -700 DEG C., preferably about 600 DEG C. for a time sufficient to form a vapor stream comprising hexafluoroisobutylene, substantially-free of perfluoroisobutylene; and (d) recovering hexafluoroisobutylene is also disclosed.
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