| 摘要 |
<p>A process for preparing an optionally substituted 4-aminodiphenylamine comprising: (i) reacting an optionally substituted aniline and an optionally substituted nitrobenzene in the presence of water and a base while controlling the amount of water in relation to the base so as to ensure a molar ratio of water to the base charged in the range of not less than 4 : 1 at the start of the coupling reaction and not less than 0.6 : 1 at the end of the coupling reaction, which is the point in time at which at most 2.0 % by weight of the limiting reagent remains unreacted in the batch, wherein the time elapsed between the start of nitrobenzene addition and the full completion of the reaction step (i) is not more than 3.5 hours, to produce 4-nitrodiphenylamine and/or 4-nitrozodiphenylamine and/or salts thereof by distilling off water; (ii) hydrogenating the reaction product of step (i) in the presence of hydrogenating catalyst and added water so as to ensure a molar ratio of total water to base of at lest 4 : 1 at the end of hydrogenation; (iii) separating the hydrogenation catalyst from the reaction mixture; (iv) obtaining an aqueous phase and organic phase from the reaction mixture, separating the organic phase from the aqueous phase and isolating the optionally substituted 4-aminodiphenylamine from the organic phase; and (v) reusing the aqueous phase from step (iv) containing recycle base in the step (i). Disclosed is also a process for preparing alkylated derivatives of optionally substituted 4-aminodiphenylamines by reductive alkylation of optionally substituted 4-aminodiphenylamines obtained by the aforementioned process.</p> |
