| 摘要 |
<p>Vinylidene fluoride is prepared by heating a bromo-1,1-difluoroethane to a temperature below 600 DEG C., preferably fron 500 DEG to 550 DEG C., maintaining the bromodifluoroethane at this temperature for a period of time below 60 seconds preferably between 5 and 30 seconds, and under a pressure which is near to atmospheric pressure, the vinylidene fluoride product being separated by conventional procedures. The bromo-1,1-difluoroethane may be prepared in situ by reacting together bromine and 1,1-difluoroethane in a molar ratio of slightly less than 1:1 at a temperature of from 350 DEG to 500 DEG C., the bromodifluoroethane being subsequently pyrolysed in the same or in a separate vessel. Examples are given. Comparative examples describe the pyrolysis of 1-chloro-1,1-difluoroethane to produce vinylidene fluoride and 1-chloro-1-fluoroethylene.</p> |
