TETRAFLUOROETHYLENE PRODUCTION PROCESS Russian patent published in 1999 - IPC

FIELD: industrial organic synthesis. SUBSTANCE: difluorochloromethane is subjected to pyrolysis in presence of steam and 1,1,2,2- tetrafluorochloroethane. Products are "quenched", freed of hydrochloric acid, neutralized, compressed, and condensed. Further, using multistage rectification, tetrafluoroethylene and fraction with boiling range from -42 to 0 C are isolated, the latter essentially containing difluorochloromethane, octafluorocyclobutane, 1,1,2,2- tetrafluorochloroethane, and hexafluoropropylene. These constituents are separated by water absorption and difluorochloromethane and 1,1,2,2- tetrafluorochloroethane are then desorbed and returned into pyrolysis process, whereas octafluorocyclobutane and hexafluoropropylene are isolated by rectifying non-absorbed gas fraction. Absorption is carried out in countercurrent mode at 5-25 C and pressure 3-7 atm in column-type apparatus passing water downward from the top and pyrolysis product from below at water-to-products weight ratio (50:150):1. EFFECT: enhanced process efficiency and new valuable product (octafluorocyclobutane) obtained. 2 cl, 2 tbl