Catalytic fluorination of trichloroethene by anhydrous hydrogen fluoride in the presence of fluorinated chromia under static conditions. Synthesis of [18F]-labelled CF3CH2F and [36Cl]-labelled CF3CH2Cl. Catalytic dehydrofluorination of CF3CH2F and CF3CH2C

Catalytic fluorination of trichloroethene by anhydrous hydrogen fluoride at 653 K in the presence of fluorinated amorphous chromia under static conditions leads to a mixture of products in which partially halogenated olefins predominate. These are converted to mixtures containing CF3CH2F and CF3CH2Cl by a second fluorination using fresh catalyst. The results of product analyses from reactions carried out under various conditions have been used to design a synthesis of [18F]-CF3CH2F from CCl2CHCl. It is proposed that [18F] labelling occurs via direct [18F]- for [19F] exchange rather than by a dehydrofluorination/hydrofluorination route. [36Cl]-labelled CF3CH2Cl is readily prepared from CF3CH2F and H36Cl in the presence of chromia catalysts. Enthalpies of dehydrofluorination of CF3CH2F and CF3CH2Cl in the vapour phase have been computed.1Non-SI units employed: Å=10−10m; a.u.≈4.36×10−18 J≈6.27089×102kcalmol−1.