METHOD FOR COMPLEX ISOLATION OF DIFLUOROCHLOROMETHANE AND HEXAFLUOROPROPYLENE Russian patent published in 2003 - IPC

FIELD: chemical technology. SUBSTANCE: invention relates to methods for separation of pyrolysis products of difluorochloromethane in production of tetrafluoroethylene with isolation of high-pure hexafluoropropylene and recurrent difluorochloromethane. High-boiling products, tetrafluoroethylene and fraction containing difluorochloromethane, hexafluoropropylene, trifluorochloroethylene and difluorodichloromethane are isolated from pyrolysis gases. Obtained fraction is subjected for absorption treatment with water at temperature 20-40 C under pressure 5-7 atm. Then extractive fractionation is carried out using the separating agent based on lower aliphatic halogen-hydrocarbon where chloroform is used. Extractive fractionation is carried out under pressure 3-6 atm by countercurrent in column and taking off pure hexafluoropropylene at 5-20 C as light fraction and chloroform is taken off from the vat at 30-50 C with absorbed impurities and chloroform is regenerated by distillation under atmosphere pressure. EFFECT: improved isolating method, simplified technology. 4 cl, 6 tbl, 1 dwg, 3 ex