The sulfochlorination first described by Cortes F. Reed in 1936 proceeds under almost identical conditions as the conventional photochlorination. In addition to chlorine, sulfur dioxide is also introduced into the reaction mixture. The products formed are alkylsulfonyl chlorides, which are further processed into surfactants.
Hydrochloric acid is formed as a coupling product, as is the case with photochlorination. Since direct sulfonation of the alkanes is hardly possible, this reaction has proven to be useful. Due to chlorine, which is bound directly to the sulfur, the resulting products are highly reactive. As secondary products there are alkyl chlorides formed by pure photochlorination, as well as several sulfochlorinated products in the reaction mixture.