Preparation of p-aminophenols

#1. Field of the Invention

#The present invention relates to the preparation of p-aminophenols from the corresponding nitrobenzenes, and, more especially, to the preparation of p-aminophenolic compounds and N-acylated derivatives thereof that are optionally substituted on their respective aromatic nucleii.

#The present invention more particularly relates to the preparation of p-aminophenol, a valuable compound economically, because it is a useful intermediate for the production of N-acetyl-p-aminophenol ("APAP").

#More particularly according to the present invention, the subject process is applicable to any benzene compound bearing an NO.sub.2 substituent, in which the position para to the NO.sub.2 substituent is unsubstituted (free).

#The process according to the invention is based on the phenomenon that the saturated aliphatic monocarboxylic acid serves both as a reaction solvent and as a nucleophilic agent involved in the Bamberger transposition, i.e., the transformation of the intermediate, namely, the conversion of a benzene compound bearing a hydroxylamine --NH--OH function into a benzene compound bearing an amino group and, in the para-position, an acyloxy group. After hydrolysis, the latter is converted into a benzene compound bearing an amino group and, in the para-position, a hydroxyl group, or, by transacetylation, is converted into an N-acylated p-aminophenolic compound.

#The process of the present invention is conducted in a saturated aliphatic monocarboxylic acid.