Catalytic reactions of chlorofluoroethanes at fluorinated alumina and chromia aerogels and xerogels

Investigation of fluorinated surfaces by means of radio-labelled probe molecules

“…The mechanistic consequence is that a halogen exchange sequence of reactions is operative on fluorinated chromia (for detailed descriptions see Refs. [28,46]), whereas the reactions that occur on fluorinated g-alumina, or on b-AlF 3 , which behaves very similarly, are better understood in terms of isomerisation and dismutation reactions; this is true particularly under 'HF free' conditions [47]. The compound CFC-113, CCl 2 FCClF 2 , has been used most often as a subject for mechanistic study.…”

“…[28]), two types of fluorinated g-alumina and b-AlF 3 [9,47]. In all cases, the isomerisation occurs via an intramolecular mechanism.…”

Recent developments in the preparation of high surface area metal fluorides

“…This HS fluoride was obtained by plasma fluorination of silica-rich zeolite, H 4 (kaolinite), resulted in a product consisting of aAlF 3 and b-AlF 3 with surface area of 32 m 2 g À1 . Formation of the HS-AlF 3 product was attributed to the low spatial density of Al atoms in the silica-rich zeolite precursor and to the fluorination under ''cold'' plasma conditions.…”

“…In some rare cases materials with surface areas larger than 100 m 2 g À1 were prepared, i.e. fluorinated chromia [3][4][5] and MgF 2 [6]. For fluorinated chromia it is clear that the material is not a pure fluoride but a mixture of fluoride and unconverted oxide [4,5].…”

γ-Alumina-supported boron trifluoride: Catalysis, radiotracer studies and computations

“…Our interest in BF 3 supported on g-alumina arose from studying the behaviour of g-alumina which had been fluorinated with sulfur tetrafluoride as a Lewis/Brönsted acid catalyst for room temperature halogen exchange involving chlorohydrocarbons [11], isomerization of 1,1,2-trichlorotrifluoroethane [12] and dismutation of 1,1,1-trichlorotrifluoroethane [13]. The acidity of SF 4 -fluorinated g-alumina can be fine tuned by modification of the conditions used for the fluorination [14].…”