Abstract: A process for producing p-nitroaniline, which comprises nitrating an .alpha.-methylbenzalaniline of the formula ##STR1## wherein R represents an alkyl group having 1 to 5 carbon atoms, and n is 0 or 1,with nitric acid in the presence of a halogenated aliphatic hydrocarbon solvent and sulfuric acid to form a p-nitro-.alpha.-methylbenzalaniline of the formula ##STR2## wherein R and n are as defined above, and hydrolyzing the p-nitro-.alpha.-methylbenzalaniline.

Abstract: Improved process for producing terephthalic acid by liquid-phase catalytic oxidation of p-xylene with oxygen at a temperature of at least about 160.degree. C. and a pressure of at least about 5 kg/cm.sup.2 G under specific recycling condition of the mother liquor, which comprises(A) performing said liquid-phase catalytic oxidation at a temperature (T) within the range of about 170.degree. C. to about 230.degree. C. to form an oxidation reaction mixture containing crude terephthalic acid having a 4-carboxybenzaldehyde content of 500 to 3,000 ppm and an optical density, measured at 340 m.mu., of not more than 0.3,(B) separating about 60 to about 98% by weight of the total mother liquor from the resulting oxidation reaction mixture at a temperaure of from (T-30).degree. C. to (T+10).degree. C.