A process for preparing benzophenones of the formula I, where X may be chlorine, hydroxyl, methoxy or C1-C6-alkylcarbonyloxy, and Y may be chlorine or bromine, by reacting an acid chloride of the formula II where X and Y are as defined above with 3,4,5-trimethoxytoluene, which comprises carrying out the reaction in the presence of a) an aromatic hydrocarbon as a diluent and b) from 0.01 to 0.2 mol % of an iron catalyst, based on the acid chloride, c) at a temperature between 60° C. and the boiling point of the particular diluent.