Journal of Physical Chemistry B, Vol.104, No.6, 1277-1284, 2000
FTIR spectroscopic and reaction kinetics study of the interaction of CF3CFCl2 with gamma-Al2O3
The interaction of CF3CFCl2 with gamma-Al2O3 has been investigated by a combination of reaction kinetics experiments and FTIR spectroscopic studies. The reaction of fresh gamma-Al2O3 with CF3CFCl2 at 573 K resulted in the fluorination of the gamma-Al2O3 surface. The reaction also resulted in dehydroxylation of the gamma-Al2O3 and an increase in both the number and strength of Lewis acid sites on the surface. The fluorinated gamma-Al2O3 was catalytically active for the disproportionation of CF3CFCl2 to CF3CCl3 and CF3CF2Cl at 353 K. Adsorption of CF3CFCl2 on gamma-Al2O3 at temperatures between 298 and 523 K resulted in the formation of surface trifluoroacetate species, which were stable up to 573 K. These species are likely to be the intermediates for the complete oxidation of CF3CFCl2 to CO and CO2. The transformation of gamma-Al2O3, as a result of the CF3CFCl2 adsorption and reaction is discussed.
Keywords:SURFACE-CHEMISTRY;CATALYTIC ALUMINAS;AL2O3 SURFACE;SITES;OXIDATION;DECOMPOSITION;CONVERSION;ADSORPTION;MECHANISM;CCL2F2