EP0334497A2
Expired / Lapsed
EP
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Method for production of maleimides
Assignee: Nippon Shokubai Co Ltd
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Filing: 1989-02-28
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Granted: —
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Expires: 2009-02-28
Abstract
Abstract A method for the production of a maleimide, which comprises effecting a former-stage reaction by adding maleic anhydride and a primary amine in amounts such that the molar ratio of said maleic anhydride to said primary amine is less than 1 under application of heat to a water-insoluble or water-immisible inert organic solvent containing an acid catalyst and subsequently carrying out a latter-stage reaction by adding to the reaction system maleic anhydride in an amount such that the molar ratio of the total amount of maleic anhydride to be added to said reaction system to the total amount of said primary amine added to said reaction system exceeds 1.
Inventors
- 👤 Yuichi Kita
- 👤 Masakazu Nakagawa
- 👤 Hitoshi Kanei
- 👤 Akio Fukui
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-09 17:32
CPC Classifications
C; C07; C07D; C07D207/00; C07D207/02; C07D207/44; C07D207/444; C07D207/448; C07D401/00; C07D401/02; C07D401/04
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
110 words
A method for the production of a maleimide, characterised by effecting a former-stage reaction by adding maleic anhydride and a primary amine in amounts such that the molar ratio of the maleic anhydride to the primary amine is less than 1 under the application of heat to a water-insoluble or water-immiscible inert organic solvent containing an acid catalyst, and subsequently carrying out a latter-stage reaction by adding maleic anhydride to the reaction system in an amount such that the molar ratio of the total amount of maleic anhydride to be added to the reaction system to the total amount of the primary amine added to the reaction system exceeds 1.
Claim 2
Independent Claim
110 words
A method for the production of a maleimide, characterised by effecting a former-stage reaction by adding maleic anhydride and a primary amine in amounts such that the molar ratio of the maleic anhydride to the primary amine is less than 1 under the application of heat to a water-insoluble or water-immiscible inert organic solvent containing an acid catalyst, and subsequently carrying out a latter-stage reaction by adding maleic anhydride to the reaction system in an amount such that the molar ratio of the total amount of maleic anhydride to be added to the reaction system to the total amount of the primary amine added to the reaction system exceeds 1.
Claim 3
Dependent Claim
71 words
A method as claimed in Claim 1, characterised in that the former-stage reaction is performed from the time the reaction is started until the time the water formed by the reaction is distilled out in an amount in the range of 40 to 99%, or preferably 50 to 80%, of the theoretical amount of water to be formed, and then the latter-stage reaction is carried out until completion of the reaction.
Claim 4
Dependent Claim
35 words
A method as claimed in Claim 1 or Claim 2, characterised in that the former-stage and latter-stage reactions are carried out at a temperature in the range of 100° to 250°C, preferably 110° to 220°C.
Claim 5
Independent Claim
28 words
A method as claimed in any preceding Claim, characterised in that the latter-stage reaction is carried out for a period in the range of 1 to 30 hours.
Claim 6
Independent Claim
84 words
A method as claimed in any preceding claim, characterised in that the molar ratio of the maleic anhydride to the primary amine in the former-stage reaction is between 0.5 and 1 and preferably between 0.7 and 1, and the molar ratio of the total amount of maleic anhydride to be added to the reaction system to the total amount of the primary amine added to the reaction system in the latter-stage reaction is between 1 and 2 and is preferably between 1 and 1.3.
Claim 7
Independent Claim
64 words
A method as claimed in any preceding Claim, characterised in that the amount of acid catalyst present is in the range of about 2 to about 400 mol%, based on the amount of the primary amine to be used and/or the amount of solvent is in the range of about 1 to about 40 times the amount of the primary amine to be used.
Claim 8
Independent Claim
19 words
A method as claimed in any preceding Claim, characterised in that the catalyst is carried on a solid carrier.
Claim 9
Independent Claim
31 words
A method as claimed in any preceding Claim, characterised in that the former-stage reaction and the latter-stage reaction are carried out in the presence of a metal-containing compound and a stabilizer.
Claim 10
Dependent Claim
56 words
A method as claimed in Claim 8, characterised in that the amount of the metal-containing compound is in the range of 0.005 to 0.5 mol%, based on the amount of the primary amine, and the amount of the stabilizer is in the range of 0.005 to 0.5 mol%, based on the amount of the primary amine.
Claim 11
Independent Claim
59 words
A method as claimed in any preceding Claim, characterised in that the maleimide is represented by the formula I: wherein R is one member selected from alkyls of 1 to 20 carbon atoms, phenyl, benzyl, cyclohexyl, pyridyl, and quinolyl, and those groups possessing a halogen, a carboxyl, or a nitro substituent; the maleimide preferably being N-phenyl maleimide or --N-cyclohexyl--maleimide.
References Cited (Backward Citations)
No citation records indexed.
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