METHOD FOR PREPARING TETRAFLUOROETHYLENE Russian patent published in 2004 - IPC

FIELD: organic chemistry, chemical technology.

SUBSTANCE: invention relates to a method for preparing tetrafluoroethylene. Method is carried out by pyrolysis of difluorochloromethane with additions of octafluorocyclobutane and 1,1,2,2-tetrafluorochloroethane as an azeotropic mixture in the presence of steam. Pyrolysis products are annealed and by-side hydrogen chloride is separated to obtain hydrochloric acid followed by neutralization, compressing and condensing and multiple-step rectifying pyrolysis products is carried out with isolation of the end product, unreacted difluorochloromethane and telomeric products of the general formula: H(CF₂)_nCl wherein n > 2. After isolation of difluorochloromethane the vat fraction is purified from toxic impurities by contact with a reagent. The latter represents hydrogen fluoride, chlorine or steam on a catalyst comprising activated carbon. Method provides reducing economical indices of the process.

EFFECT: improved preparing method.

12 cl, 1 tbl, 14 ex