| 摘要 |
A process for the preparation of maleimides and dimaleimides in high yield, wherein in the first step maleic anhydride and a suitable primary amine or diamine are contacted at about 30 DEG -60 DEG C. in the presence of a simple, cheap organic solvent; and in the second step the thus-formed intermediate is cyclized, without prior isolation, at 45 DEG -60 DEG C. in the presence of a lower fatty acid anhydride, a tertiary amine having a pKa of at least 10 and of a salt of magnesium, lithium, manganese(II), or cobalt(II) soluble in the liquid reaction medium to the extent of at least 0.2 weight percent. Alternatively, the tertiary amine can be added in the first step. The product maleimide or dimaleimide normally can be isolated by filtration after cooling to room temperature. Water-miscible solvents may be diluted with water prior to product isolation. Certain N,N'-arylene-dimaleimides, which can be prepared by this process, are vulcanization adjuvants for elastomers.
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