FLUORINATION OF GAMMA-ALUMINA BY SULFUR-TETRAFLUORIDE, THIONYL FLUORIDE, CARBONYL FLUORIDE OR ANHYDROUS HYDROGEN-FLUORIDE - A RADIOTRACER STUDY

The interaction of gamma-alumina, previously calcined at 523K, with SF 4, OSF2, OCF2 or anhydrous HF, nominally at room temperature, can be f ollowed conveniently using the radiotracer, fluorine-18. The reactions involving SF4, OSF2 or OCF2 are best described as surface-induced hyd rolyses in which the expected products, OSF2 + SO2, SO2 or CO2 are des orbed rapidly whereas the other product, HF, is essentially retained b y the solid. Fluoride contents of the latter have been estimated and t he lability of fluorine exchange with respect to SF4 and anhydrous HF determined. There is no evidence for aluminium(III) fluoride formation and an explanation is offered in terms of the structure of gamma-alum ina.