p-Toluenesulfonic acid → 2-Chlorotoluene-4-sulphonic acid

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Reaction Steps

In a typical process for preparing an aqueous solution of an alkali metal salt of 2-chloro-5-amino-4-toluene sulfonic acid, toluene is first reacted with sulfuric acid to produce para-toluene sulfonic acid as the principal product. The sulfonic acid is then reacted with chlorine to produce 2-chloro-para-toluene sulfonic acid as a principal product which is reacted with a mixture of 50 percent nitric acid and 50 percent sulfuric acid to produce 2-chloro-5-nitro-para-toluene sulfonic acid. The nitrated product is then neutralized in an aqueous lime slurry which is subsequently filtered. The aqueous nitrated product is then iron reduced to form an amine and the reaction mixture is neutralized with sodium hydroxide to a pH of about 9.5-10.5 and the resulting solution is subsequently filtered.

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