There are prepared acyl cyanides of the formula ##STR1## where R is a straight or branched chain alkyl group having 1 to 18 carbon atoms, preferably 1 to 10 carbon atoms, and which also can be substituted by one or more phenyl groups or halogen atoms, preferably chlorine, or R is preferably a cycloalkyl group having 3 to 8 carbon atoms, preferably cyclopropyl, which can have one or more 1 to 3 carbon atom alkyl or halogen, preferably chlorine, substituents wherein in all of the above set forth substitutions the halogen atoms and the phenyl groups are not on the carbon atom adjacent to the carbonyl group or R is a substituted phenyl group, a naphthyl group, a substituted naphthyl group or a five membered heterocyclic group, e.g., furyl, thienyl or alkyl substituted thienyl, wherein the substituents on the phenyl or naphthyl are halogen atoms, nitro groups or alkyl or alkoxy groups having 1 to 5 carbon atoms. The process comprises reacting an acyl halide of the formulaR -- Co -- Hal (II)in which R is as defined above and Hal is a chlorine or bromine atom, with CuCN at a temperature of about 50.degree. to 180.degree. C in the presence of a carboxylic acid nitrile inert under the reaction conditions, there being employed about 1 to 10 parts by weight of the carboxylic acid nitrile and about 0.5 to 20 parts by weight of at least one organic solvent which is inert under the reaction conditions. Certain of the compounds are novel per se.