| abstract |
Substituted benzaldehydes are prepared by reaction of the substituted benzenes from which they are derived with carbon monoxide and hydrogen chloride in the presence of metal halides, the process being performed in the presence of 0.5 to 10 mols of hydrogen chloride per mol of metal halide at a partial pressure of carbon monoxide from 1 to 100 bars and a temperature from -20 DEG C. to +100 DEG C. and, if desired, in the presence of an inert diluent. The substituted benzaldehyde which contains, as a substituent, alkyl with at least 2 carbon atoms, cycloalkyl or optionally substituted benzyl, is prepared by reacting the appropriately substituted benzene with the additional presence of a benzene which does not contain the substituents mentioned, but which is identical in respect of further substituents which are optionally present with the benzene from which it is derived. |