HETEROGENEOUS CATALYZED SYNTHESIS OF 1,1,1,2-TETRAFLUOROETHANE FROM 1,1,1,2-TETRACHLOROETHANE - THERMODYNAMICS AND REACTION PATHWAYS

1,1,1,2-Tetrachloroethane and its fluorinated derivatives, as well as trichloroethene, were fluorinated by hydrogen fluoride in the presence of a preconditioned chromia catalyst. The reaction pathways were deri ved under different conditions. Fluorinated haloalkanes are formed bot h by dehydrochlorination/hydrofluorination mechanisms as well as a chl orine/fluorine exchange mechanism. Thus, beside fluorinated alkanes co nsiderable amounts of halo-olefins occur in the product mixture. A sur vey is given of the reaction pathways showing their dependence on the reaction conditions. These are discussed with respect to the calculate d thermodynamic data.