| 摘要 |
An improved process for the preparation of methylene-bridged polyarylpolyamines by the acid catalyzed condensation reaction of an aromatic primary amine and formaldehyde is disclosed wherein nitrilotriacetic acid is employed as the catalyst system. An aromatic primary amine and formaldehyde are mixed and reacted at an elevated temperature in the presence of a catalytic amount of nitrilotriacetic acid which provides a resulting reaction product that does not have to be subjected to neutralization procedures or filtration for catalyst removal as heretofore required. The reaction product mixtures of methylene-bridged polyarylpolyamines has excellent color and can be employed without further treatment as epoxy curing agents, urethane cross linkers, as precursors for the preparation of corresponding methylene-bridged polyarylpolyisocyanates, and the like. The employment of nitrilotriacetic acid also leads to the completion of the condensation reaction in relatively short periods of time.
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