Aluminium (III) chloride catalysed dehydrochlorination of 1,1,1-trichloroethane is industrially important, as it is considered to be one of the first steps in the degradation of 1,1,1-trichloroethane based solvents used in the large scale vapour degreasing of aluminium. The degradation and fouling observed has been attributed to aluminium (III) chloride catalysed dehydrochlorination of the solvent, followed by aluminium (III) chloride catalysed oligomerisation of the dehydrochlorinated product. There is evidence that heterogeneous phenomena are of importance in these reactions, and in this work the reactions of gaseous 1,1,1-trichloroethane and 1,1-dichloroethene with solid aluminium (III) chloride were studied.