PURPOSE: To obtain the titled compound useful as a synthetic intermediate of dye, etc., economically, quantitatively, at a low cost, by sulfonating chlorobenzene, nitrating the product, and hydrolyzing with an acidic catalyst in the presence of a mineral acid.
CONSTITUTION: Chlorobenzene is sulfonated, and the obtained 4-chlorobenzene- sulfonic acid is nitrated to obtain 4-chloro-3-nitrobenzene-sulfonic acid. The acid is hydrolyzed with an acidic catalyst in the presence of a mineral acid to obtain o-nitrochlorobenzene. The nitration is carried out at 20W80°C, preferably 40W 60°C. The desulfonation reaction is performed by adjusting the sulfuric acid concentration to 20W90%, preferably 40W60%, and raising the reaction temperature to 80W150°C, preferably 120W150°C.