Invention Grant
US08759585B2 Two-stage process for cost-effective deposition of homogeneous catalysts in MDA synthesis 有权
在MDA合成中成本有效地沉积均相催化剂的两阶段方法

Two-stage process for cost-effective deposition of homogeneous catalysts in MDA synthesis
Abstract:
The invention provides a process for preparing diphenylmethanediamine, comprising the steps of: a) reacting aniline with formaldehyde in the presence of an acid, b) neutralizing the predominant part of the acid with ammonia and/or aqueous ammonia solution, c) separating the reaction mixture from step b) into an aqueous phase and an organic phase, d) neutralizing the other part of the acid, present in the organic phase, with aqueous alkali metal hydroxide solution, e) separating the reaction mixture from step d) into an aqueous phase and an organic phase, f) treating the aqueous phase obtained in step c) or optionally the combined aqueous phases from steps c) and e) with at least one oxide or hydroxide of an alkaline earth metal, g) removing the ammonia obtained in step f).
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