Chlorosulfuric acid, reaction with aromatic

Aromatic sulfonyl chlorides can be prepared directly, by treatment of aromatic rings with chlorosulfuric acid. ° Since sulfonic acids can also be prepared by the same reagent (11-7), it is likely that they are intermediates, being converted to the halides by excess chlorosulfuric acid. The reaction has also been effected with bromo-and fluorosulfuric acids. 

Chlorosulfuric acid (HSO3CI) reacts with aromatic hydrocarbons to give sulfonic acids, sulfonyl chlorides, and sulfones, with the relative yields depending on the reaction conditions. The reaction with benzene with an equimolar amount of... 

SAFETY PROFILE Poison by ingestion, subcutaneous, intravenous, and intraperitoneal routes. Moderately toxic by intramuscular route. Can cause liver and kidney damage. The liquid phenol reacts violendy with KOH. Product of reaction with chlorosulfuric acid decomposes violendy at 24°C. When heated to decomposition it emits toxic fumes of NOx. See also NITRO COMPOUNDS OF AROMATIC HYDROCARBONS. 

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