Process for the preparation of aromatic sulfonyl chlorides

Abstract

A process for the preparation of aromatic sulfonyl chlorides of the formula I ##STR1## in which R.sub.1, R.sub.2 and R.sub.3 are identical or different and are hydrogen, fluorine, chlorine, bromine or iodine atoms, alkyl(C.sub.1 -C.sub.4), acetamido, nitro or carboxyl groups, or R.sub.1 and R.sub.2 together form an aromatic or heteroaromatic ring having 5 or 6 ring members, which can be substituted by fluorine, chlorine, bromine or iodine atoms, alkyl(C.sub.1 -C.sub.4), acetamido, nitro or carboxyl groups, by reaction of aromatic compounds of the formula II ##STR2## in which R.sub.1, R.sub.2 and R.sub.3 have the abovementioned meanings, with chlorosulfonic acid in excess or with chlorosulfonic acid or oleum and thionyl chloride, by reacting in the presence of sulfamic acid as a catalyst.

Dependencies are inferred from the claim text.