X, K-Bis-(trifluoromethy1)-amides, RCON (CFS)~, where R= alkyl or perfluoroalkyl, 15ere made in good yield by the reation of acyl halides with the mercury derivative of bis- (trifluoromethy1)-amine Perfluoroacyl amides, RCOKHCORF, were made by reaction of appropriate nitriles with acids, or amides with acid anhydrides or acid halides. Introduction of the second acyl group affected adversely most amide reactions; thus, CF3CONHCH3 ...