| 摘要 |
PURPOSE:To obtain amino diphenylamines efficiently and at a low cost directly, by reducing azobenzenes in the presence of a base under specific conditions while suppressing excessive hydrogenation to form hydrazobenzene, which is subjected to thermal rearrangement. CONSTITUTION:Azobenzenes having substituents, e.g. alkoxy and amino groups, etc. with electron donative properties at the o-and p-positions are catalytically reduced in the presence of an inorganic base, such as alkali metal hydroxide, etc., or an organic base, such as pyridine, etc. at 80-230 deg.C, preferably 100-200 deg.C, to form an intermediate for hydrazobenzenes (by the primary hydrogenation). The intermediate is then subjected to heat rearrangement (the secondary hydrogenolysis reaction) to form aminodiphenylamines. Catalysts whose secondary hydrogenolysis activities are lost by poisoning can be used instead of a very small amount of the base. USE:Intermediates for dyes, and pharmaceuticals. |
