RADIOTRACERS IN FLUORINE CHEMISTRY .18. SULFUR-TETRAFLUORIDE CHLOROFLUORINATION CATALYZED BY GROUP-1 FLUORIDES SUPPORTED ON FLUORINATED GAMMA-ALUMINA - A COMPARISON WITH UNSUPPORTED FLUORIDES

Caesium or potassium fluorides supported on gamma-alumina and then exh austively fluorinated with SF4, F2SO or anhydrous HF (in the latter ca se after SO2 pretreatment) are effective catalysts for the room-temper ature chlorofluorination of SF4 by C1F to give SF5Cl. Kinetic studies using chlorine-36 and sulphur-35 radiotracers indicate that the maximu m catalytic activity corresponds to a metal fluoride loading of 5.5 mm ol g-1, consistent with previous radiotracer adsorption studies. At th is loading, the behaviour of supported CsF is comparable to that of un supported CsF which has been activated by treatment with (CF3)2CO. Act ivated commercial mercury(II) fluoride is a less active catalyst.