OCTAFLUOROCYCLOBUTANE AND HEXAFLUOROPROPYLENE PRODUCTION PROCESS Russian patent published in 2002 - IPC

FIELD: industrial organic synthesis. SUBSTANCE: ozone-safe refrigerant octafluorocyclobutane and valuable monomer hexafluoropropylene are prepared by heat treatment of tetrafluoroethylene at excessive pressure in flow-through system. Crude product, prior to be fractioned, is fried of perfluoroisobutylene by bringing it into contact with chemical reagent, in particular (1) wateralkali solution of triethylamine, with which product is sprinkled to give less harmful hexafluoroisobutyric acid; or (ii) hydrogen fluoride, with which reaction proceeds at 80-200 C in presence of activated carbon to give 2- hydroperfluoroisobutane; or (iii) water steam in contact with activated carbon at 120-250 C at 10-100- fold volumetric excess of steam to give hexafluoroisobutyric acid; or (iv) suspension of potassium fluoride in polyfluorinated alcohol (tetrafluoroethylene/methanol telomerization product), through which gaseous product is bubbled to give polyfluorinated ester. Such treatments reduce high-toxicity perfluoroisobutylene in bottom fraction to a level below 0.5 mol %. EFFECT: simplified fractionation operation. 5 cl, 4 ex