METHOD OF PREPARING TETRAFLUOROETHYLENE Russian patent published in 2001 - IPC

FIELD: chemical industry. SUBSTANCE: process comprises pyrolysis of difluoroechloromethane with additives of octafluorocyclobutane and 1,1,2,2-tetrafrluorochloroethane as azeotropic mixture in the presence of steam, hardening of pyrolysis products, separation of hydrogen chlorine by-product to prepare hydrochloric acid, neutralization, compression and condensation of pyrolysis products and separation of desired product, unreacted difluorochloromethane and by multistep rectification thereof. Process is carried out by adding diethylamine either into still of rectification column intended for isolation of difluorochloromethane or into still of rectification column intended for isolation of azeotropic mixture. Contamination with toxic unsaturated compounds is thus reduced due to conversion of said compounds into low-volatile compounds. EFFECT: more efficient preparation method. 3 cl, 3 ex, 1 tbl