3-Aminophenol

m-Aminophenol (MAP) is an important starting material for dyes, including a variety of leuco (or latent) dyes used in imaging technology, optical bleaches and fluorescent agents, drugs, agricultural chemicals; and high-performance polymers. Although the synthesis of m-aminophenol(s) by the reaction of resorcinol with ammonia or (di)alkylarnines has been known for about 100 years,the preferred manufacturing process had been for many years a route involving the sulfonation of nitrobenzene to m-nitrobenzenesulfonic acid, the reduction of the nitro group to give m-aminobenzenesulfonic acid, followed by the caustic fusion of sodium m-aminobenzenesulfonate to yield sodium m-aminophenolate. The m-aminophenol was isolated/purified by neutralization, filtration, and recrystallization; the overall yield of m-aminophenol from nitrobenzene was estimated by SRI International to be 58%. (Doubtless, process improvements were made by the producers using this process.) The nitrobenzene/sulfonationlreductionlcaustic fusion route is still being used commercially, notably by ACNA in Italy, the largest producer of MAP, as well as a few smaller manufacturers. Sumitomo Chemical Co. used this process as well into the early 1980s and had licensed their knowhow to Hindustani Organic Chemicals, Ltd. of India which started up a plant on this basis with a capacity for MAP of 1.5 mill. lb /yr in 1970.The output of the Indian plant was said to be devoted to making sodium p-aminosalycilate (PAS), a tuberculostatic agent.
Light grey crystal powder