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US 4,904,803 AGranted
Process for producing N-substituted maleimides
AssigneesNitto Chemical Industry Co., Ltd., Mitsubishi Rayon Co., Ltd.
InventorsTakeyuki Fujita, Tuyoshi Irie, Yasuyuki Takayanagi, Takeshi Narita, Yuya Yano
Life of this patent
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Abstract
N-substituted maleimides are prepared by reacting maleic anhydride with an amine in the presence of Cu or a copper compound and purifying the maleimide produced in the absence of presence of said Cu or copper compound. N-substituted maleimides are widely useful or starting materials or intermediates for medicines, agricultural chemicals, dyes, macromolecular compounds, and the like.
Claims13
A process for producing N-substituted maleimides, which comprises:
- (1) synthesizing an N-substituted maleimide by reacting maleic anhydride with an amine selected from the group consisting of aromatic primary amines and aliphatic primary amines in the presence of a catalyst which promotes the formation of N-substituted maleimide and of at least one member selected from the group consisting of metallic copper and copper compounds, and
- (2) purifying the N-substituted maleimide product of step (1) by (i) washing the N-substituted maleimide-containing reaction product mixture with at least one liquid selected from a dilute aqueous alkali solution, water, and a dilute aqueous acid solution, and (ii) isolating the N-substituted maleimide from the washing organic layer.
A process for purifying N-substituted maleimides which comprises steps of
- washing an N-substituted maleimide-containing reaction product mixture resulting from reacting maleic anhydride with an aromatic or aliphatic primary amine, with at least one liquid selected from a dilute aqueous alkali solution, water, and a dilute aqueous acid solution, and
- isolating the maleimide from the resulting organic layer.
Dependencies are inferred from the claim text.