Hoechst Aktiengesellschaft

Dyneon Gmbh

Thomas Schottle

Herbert Weber

Karl Rettenbeck

Klaus Hintzer

Ingolf Mielke

Reinhold Freudenreich

Gerd Muller

Werner Dostler

Hans J Staudt

The polymerization of tetrafluoroethylene in aqueous suspension can be carried out with high conversion if the medium is thoroughly mixed using an axially conveying stirrer element in such a manner that a cone forms at least as far as the vicinity of the stirrer element. In the region of this stirrer element there are expediently arranged baffles which extend only over a part of the filling height of the reactor.

Process and device for preparing a polymer of tetrafluoroethylene in

The pyrolysis of fluorine polymers leads to a high yield of pure fluorinated monomers if the finely divided polymer is introduced, with steam, into a fluidized bed reactor which contains an inert, granular material as the fluidized material, the steam functioning as the fluidizing gas.

Process for the preparation of fluorinated monomers

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.

Process for the preparation of hexafluoropropene

A process for the preparation of mixtures of chlorotetrafluoroethane and octafluorocyclobutane from the gas stream from the pyrolysis of chlorodifluoromethane at temperatures above 600.degree. C. is described in which the principal constituents tetrafluoroethylene and hexafluoropropylene as well as hydrogen chloride are removed in advance. The mixtures are obtained by withdrawal as a side fraction during the rectifying distillation of the residue remaining, a clean separation of the perfluorocyclobutenes advantageously taking place. The mixtures are used for obtaining hexafluoropropylene by pyrolysis.

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Burghausen, Germany

Thomas Schottle