METHOD OF PRODUCING OCTAFLUOROCYCLOBUTANE Russian patent published in 1997 - IPC

FIELD: production of process liquids. SUBSTANCE: invention relates to production of ozone-safe fluorohydrocarbon useful as cooling agent, air sol propellant, and working medium for heat pumps. Method includes cyclodimerization of tetrafluoroethylene at elevated temperature and pressure and isolation of desired product by fractionation. Cyclodimerization is proposed to be carried out in preliminarily heated to 400-650 C thermally insulated reactor under adiabatic condition in flow system under pressure not higher than 0.7 gage atm developed by flow system and system of reaction product processing. Heat loss is compensated by feeding into reactor jacket of heat carrier heated to the above-indicated temperature, advantageously air or superheated steam, maintaining this temperature in reaction zone. Reactor is cylindrical- shaped with length to diameter ratio within the range 3 to 65 and made of heat resistant stainless steel, nichrome, or nickel. One liter of reaction volume receives 0.5-20 kg/h of tetrafluoroethylene. Process is carried out to conversion level 30-85%. Reaction products are cooled and condensed. Except for desired product, nonreacted tetrafluoroethylene is isolated from condensate and returned into reactor. Method is characterized by high productivity, negligible formation of side products, and reliable controllability, which excludes explosion danger. EFFECT: enhanced efficiency of process. 13 cl, 1 tbl