ABSTRACT
m-Aminophenol is a monomer which is being increasingly utilized as an intermediate in the synthesis of unsymmetrical diaminodiphenyl ethers, which are key intermediates to new classes of polymers, and in the synthesis of thermal- and pressure-sensitive dyes used in imaging. To date, MAP has mainly been manufactured by nitrobenzene sulfonation, reduction to m-aminobenzenesulfonic acid, and caustic fusion. This process is not environmentally acceptable today because of its large salt by-product. Sumitomo has recently commercialized a new process based on the aminolysis of resorcinol. The scope of effective metals for catalysis of the partial hydrogenation was quite limited. The most effective catalyst both in terms of rate and 3-ACI selectivity was palladium on a carbon support. The isolation of the acetate and hydrochloride salts of 3-ACI were achieved by recrystallization of the resulting crude oil after removing the aqueous acid solution under vacuum.
