Composition catalytique

摘要

A fluorocarbon catalyst is made by treating activated Al2O3 with the vapour of a lower fluorocarbon containing not more than 8 carbon atoms and not more than one hydrogen atom at an elevated temperature and not exceeding 800 DEG C. which is effective to promote the reaction of the fluorocarbon with the alumina causing evolution of carbon oxides (i.e. CO, CO2, COCl2 and/or COClF), and containing the treatment until the evolution of the carbon oxides has substantially ceased. Preferably the activated Al2O3 is essentially unmodified by other materials. The activated Al2O3 may be dried before treatment with fluorocarbon vapour. The catalyst may be used for disproportionation and/or rearrangements of fluorocarbon in fixed or fluidized bed operation. Example E and Examples 24-30 describe the use of a Cr2O3-containing Al2O3 activated catalyst. Example 13 describes the regeneration of spent activated Al2O3 catalysts by oxidation at 300 DEG -400 DEG C.ALSO:Fluorochloroalkanes are disproportionated and/or rearranged by contacting their vapours with an Al2O3 catalyst activated by treatment with the vapour of a fluorocarbon containing not more than 8C and one or no hydrogen atoms, and which may contain chlorine atoms, at an elevated temperature, not exceeding about 800 DEG C., so as to liberate carbon oxides (i.e. CO, CO2, COCl2 and/or COCIF), treatment being continued until evolution of carbon oxides has substantially ceased. Examples of indicated reactions are:- When C2Cl6 is produced it may break down to provide C2Cl4 and Cl2. Disproportionations and rearrangements may occur simultaneously and selection of product is determined by catalyst temperature and/or modification of catalyst e.g. by inclusion of a minor proportion of Cr2O3. Disproportionation occurs between 150 and 600 DEG C. and between 1/10 and 10 atmospheres pressure. Reaction products and unreacted starting materials, leaving the catalyst bed may generally be condensed by cooling and/or compression to form a liquid one phase mixture from which the desired products may be separated by fractional distillation and unreacted material recycled to the catalyst bed. Examples are given.