Acyl chlorides are prepared by reacting a carboxylic acid or its anhydride with carbonyl chloride in the presence of a carboxamide of the formula I ##STR1## where R.sup.1 is a radical of the formula ##STR2## R.sup.2 and R.sup.3 are each alkyl of 1 to 9 carbon atoms, R.sup.4 and R.sup.5 are each hydrogen or alkyl of 1 to 9 carbon atoms and the two radicals R.sup.1 and R.sup.2 may furthermore be a hydrocarbon radical which completes the moiety ##STR3## to form a heterocyclic structure, and the stated alkyl and hydrocarbon radicals may furthermore contain substituents which are inert under the reaction conditions.