Disproportionation of N-arylhydroxylamines in the presence of hydrogenation catalysts and sulfur compound additives

Data are presented for the hydrogenation of p-chloronitrobenzene (PCNB) in the presence of a catalyst containing 2% platinum on activated charcoal and added thiophene, sulfolane, and 2,4-dimethylsulfolane in ethyl acetate at 20 C. The yield of N-arylhydroxylamines increases in the liquid-phase catalytic hydrogenation of aromatic nitro compounds due to a reduction in the rate of the secondary transformations of these products upon the introduction of thiophene, sulfolane and other sulfur compound additives.