| 摘要 |
A saturated solution of an alkaline earth or alkali metal halide salt is electrolyzed in a flowing mercury cathode electrolysis cell. The amalgam is added dropwise to a solution of dichlorodifluoromethane in a solution of a polar, aprotic solvent, not reducible by such amalgams. The solvent contains inhibitors of polymerization, and may contain a promoting salt of lithium or the "onium" type. Tetrafluoroethylene and unreacted dichlorodifluoromethane gases are evolved, and separated by condensing the dichlorodifluoromethane. The polar, aprotic solvent is removed from the reaction and evaporated, crystallizing the chloride salt of the alkaline earth or alkali metal. This salt is combined with the anolyte of the mercury cell to form brine. The spent mercury from the dechlorination and dimerization is also recycled to the mercury cell. The polar, aprotic solvent is condensed, and mixed with the condensed unreacted dichlorodifluoromethane for further dechlorination and dimerization. The tetrafluoroethylene gas is polymerized in aqueous media, under heat and pressure to form polytetrafluoroethylene.
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