Continuous process for preparing chlorotrifluoroethylene

Abstract

The subject is the preparation of chlorotrifluoroethylene (CTFE) by a known reaction of 1,1,2-trichloro-1,2,2,-trifluoroethane (R-113) with zinc powder dispersed in an alcohol such as methanol, and the object of the invention is industrially easily and smoothly carrying out the reaction in a continuous manner. The disclosed process uses a plurality of stirred tank reactors, usually two or three reactors, which are connected to each other in a series arrangement by overflow pipes. A dispersion of zinc powder in an alcohol is continuously fed into the first reactor only so as to allow the dispersion to overflow into the next reactor and then into the remaining reactor(s) in turn, and R-113 is continuously fed into each reactor. CTFE is continuously discharged from each reactor, while zinc in the initially fed dispersion is gradually converted into zinc chloride. In the last reactor the conversion of zinc reaches 90% or above. Together with the remaining zinc powder the solution of zinc chloride in the alcohol is continuously discharged from the last reactor and can easily be recovered.