Processes for the production of hexafluoropropene and optionally other halogenated hydrocarbons containing fluorine

Abstract

A process is disclosed for the manufacture of CF,CF═CF,, and optionally a least one compound selected from CF,CH,CF,and CF,CHFCHF,. The process involves contacting a reactor feed including a precursor stream of at least one halogenated propane of the formula CX,CH,CH,X,and/or halogenated propene of the formula CX,CH═CH,X,, where each X is Cl or F and y is 0, 1 or 2 (provided that the average fluorine content of the precursor stream is no more than 5 fluorine substituents per molecule) with HF and Cl,in a chlorofluorination reaction zone containing a fluorination catalyst and operating at a temperature between about 150° C. and 400° C., to produce a reaction zone effluent including HF, HCl and a mixture of reaction products of the precursor feed which contains at least one compound of the formula C,Cl,F,including CClF,CClFCF,and at least one compound of the formula C,HClF,, including CHF,CClFCF,and has an average fluorine content which is at least one fluorine substituent per molecule more than the average fluorine content of the precursor stream. The chlorofluorination reaction zone effluent is distilled to produce (i) a low-boiling component including HCl (and when they are present in the reaction zone effluent, C,F,, C,ClF,and C,HF,), (ii) a hydrogenation feed component containing at least one compo of the formula C,Cl,F,including CClF,CClFCF,and at least one compound of the formnula C,HClF,including CHF,CClFCF,, and an underfluorinated component including halogenated propanes containing at least one chlorine subtituent and from one to five fluorine substituents. The CClF,CClFCF,and CHF,CClFCF,of hydrogenation feed component (ii) is reacted with hydrogen to produce a mixture including CF,CF═CF,and CF,CHFCHF,and the CF,CF═CF,from this product mixture is recovered. Underfluorinated component (iii) is returned to the chlorofluorination reaction zone.