Production of crude aniline for use in producing di- and polyamines, involves purifying crude aniline by adding aqueous alkali metal hydroxide solution to crude aniline prior to and/or during distillation

摘要

Crude aniline is produced by hydrogenating nitrobenzene in the presence of a catalyst to produce crude aniline, and purifying the crude aniline by single- or multi-stage distillation. An aqueous alkali metal hydroxide solution is added to the crude aniline prior to distillation and/or during distillation of the crude aniline, and is adjusted to maintain molar ratio of alkali metal hydroxide to phenolic compounds present in the crude aniline at 0.1:1-10:1. Independent claims are included for: (1) a process of producing di- and polyamines in the diphenyl methane series; and (2) a process for producing di- and polyisocyanates in diphenyl methane series.