| 摘要 |
<p>Fluorocarbons, e.g. tetrafluoroethylene, are made by heating carbon with a compound of the formula F2C=X, where X is sulphur or oxygen, at a temperature of at least 1500 DEG C., preferably 2,500 DEG to 4,000 DEG C. The process may suitably be carried out (a) by passing the vaporized compound F2C=X through a tube made of carbon or of other refractory material packed with carbon at a temperature of 1500 DEG C.; (b) by passing the compound F2C=X through a carbon are, or (c) when the starting material is a liquid, by submerging the carbon are in the liquid fluorine-containing compound. The carbon are may suitably be operated at a current of 10 to 30 amps. at 10 to 50 volts. Preferably the hot reaction products are cooled rapidly to below 400 DEG C., in less than 1 second and more preferably in 0.001 to 0.1 second. Apparatus for carrying out the process by means of a carbon are and a flow sheet of the process which permits unreacted starting material and undesired fluorocarbon products to be recycled are described with reference to drawings. Examples describe pyrolysis in a carbon are of (1) carbonyl fluoride (contaminated with phosgene and carbonyl chlorofluoride) to give tetrafluoroethylene, carbon tetrafluoride, dichlorodifluoromethane and chlorotrifluoromethane and (2) and (3) pure carbonyl fluoride to give tetrafluoroethylene, carbon tetrafluoride and hexafluoroethane. Specifications 760,657 and 766,324 are referred to.</p> |
