Radiotracers in fluorine chemistry. Part 12. Reactions between caesium fluoride and arsenic pentafluoride, boron trifluoride, sulphur tetrafluoride, carbonyl fluoride, and carbon dioxide under heterogeneous conditions at room temperature. Radiotracer studies using fluorine-18, sulphur-35, and carbon-14

Abstract

Activation of CsF by thermal decomposition of its 1 : 1 adducts with hexafluoroacetone or carbonyl fluoride results in significantly greater activity with respect to its reactions with AsF₅, BF₃, and SF₄ under heterogeneous conditions at room temperature, and enables reactions involving carbonyl fluoride and carbon dioxide to be studied. The results of radiotracer experiments employing ¹⁸F and ³⁵S or ¹⁴C are consistent with the occurrence of weakly adsorbed SF₄ or F₂CO at the surface of activated CsF in addition to permanently retained species SF₅^– and F₃CO^–. Carbon dioxide interacts weakly with activated CsF. Room-temperature ¹⁸F exchange occurs between ¹⁸F-labelled F₂CO and activated CsF. It is not observable in the other systems but does occur at 373 K. It is suggested that the CsF activation process results in a pore structure for the solid and that this is responsible for its increased reactivity.