a process for the purification of crude 4 - aminophenol which was prepared by the catalytic hydrogenation of nitrobenzene in aqueous sulfuric acid is described involving : adjusting the ph of an aqueous solution of crude 4 - aminophenol to ph 4 . 0 - 5 . 0 at a temperature between 75 ° c . and 85 ° c . ; mixing the aforesaid solution with toluene as the solvent , in order to extract various impurities and the dissolved nitrobenzene starting material ; adjusting the ph of the resultant solution as required to maintain it at ph 4 . 0 - 5 . 0 ; allowing the resultant mixture to settle thereby forming a top organic layer and a bottom aqueous raffinate layer which raffinate contains 4 - aminophenol and the by - product material , ortho - aminophenol ; separating the two layers and repeatedly extracting the raffinate layer which toluene at ph 4 . 0 - 5 . 0 at a temperature of 75 °- 85 ° c . until most impurities have been removed from the resultant final raffinate ; adding to the resultant raffinate , a charcoal decolorizing agent and a sodium sulfite type salt , which are then removed , leaving a filtrate which contains the 4 - aminophenol and also the by - product ortho - aminophenol ; adjusting the ph of said filtrate to ph 6 . 5 - 8 . 0 and cooling it to a temperature below 10 ° c . ; separating the precipitated pure 4 - aminophenol from the by - product ortho - aminophenol which remains in the solution .