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US5068357A
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Preparation of n-substituted maleimides by use of tin catalysts
Assignee: Mitsui Toatsu Chemicals Inc
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Filing: 1990-06-11
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Granted: 1991-11-26
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Expires: 2010-06-11
Abstract
Abstract A process for the preparation of N-substituted maleimides by conducting heat-dehydration and dehydrating imidization of N-substituted maleamic acids under azeotropic distillation of generated water in a solvent mixture containing a solvent capable of forming water azeotrope and an organic aproptic polar solvent, in the presence as catalyst of metallic tin, tin oxide, a tin salt of a maleamic acid or a tin compound which forms a thin salt of the N-substituted maleamic acid in the reaction system.
Inventors
- 👤 Ryuichiro Tsumura
- 👤 Teruo Muraishi
- 👤 Keiichi Ideda
- 👤 Jin-Kai Wang
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 17:50
CPC Classifications
C; C07; C07D; C07D207/00; C07D207/02; C07D207/44; C07D207/444; C07D207/448
Claims Analysis
Total Claims: 21
Claim 1
Independent Claim
108 words
In a process for the preparation of an N-substituted maleimide by heat-dehydrating an N-substituted maleamic acid in a solvent mixture containing an organic solvent capable of forming water azeotrope and an organic aprotic polar solvent and simultaneously conducting a dehydrating imidization reaction under azeotropic distillation of the reaction generated water, the improvement which comprises conducting the dehydrating imidization in the absence of an acid catalyst and in the presence of one or more catalyst selected from the group consisting of metallic tin, tin oxide, a tin salt of the maleamic acid and a tin compound which forms a tin salt of the maleamic acid in the reaction system.
Claim 2
Dependent Claim
108 words
In a process for the preparation of an N-substituted maleimide by heat-dehydrating an N-substituted maleamic acid in a solvent mixture containing an organic solvent capable of forming water azeotrope and an organic aprotic polar solvent and simultaneously conducting a dehydrating imidization reaction under azeotropic distillation of the reaction generated water, the improvement which comprises conducting the dehydrating imidization in the absence of an acid catalyst and in the presence of one or more catalyst selected from the group consisting of metallic tin, tin oxide, a tin salt of the maleamic acid and a tin compound which forms a tin salt of the maleamic acid in the reaction system.
Claim 3
Dependent Claim
52 words
The process of claim 1 wherein the N-substituted maleamic acid is selected from the group consisting of N-methylmaleamic acid, N-butylmaleamic acid, N-octylmaleamic acid, N-dodecylmaleamic acid, N-stearylmaleamic acid, N-cyclohexylmaleamic acid, N-phenylmaleamic acid, N-(o-tolyl)maleamic acid, N-dodecylphenylmaleamic acid, N-chlorophenylmaleamic acid, N-dichlorophenylmaleamic acid, N-(o- or p-hydroxyphenyl)maleamic acid, N-(o- or p-methoxyphenyl)maleamic acid, N-(m-hydroxycarbonylphenyl)maleamic acid and N-(m-nitrophenyl)maleamic acid.
Claim 4
Dependent Claim
40 words
The process of claim 1 wherein the N-substituted maleamic acid is selected from the group consisting of N,N'-(m- or p-phenylene)bis-maleamic acid, N,N'-(2,4-tolylene)bis-maleamic acid, N,N'-(4,4'-diphenylmethane)bis-maleamic acid, N,N'-(4,4'-diphenylether)bis-maleamic acid, N,N'-(4,4'-diphenylketone)bis-maleamic acid, N,N'-(4,4'-diphenyldisulfide)bis-maleamic acid, N,N'-(4,4'-diphenylsulfone)bis-maleamic acid, N,N'-(4,4'-p-xylylenediphenyl)bis-maleamic acid and a polymeric homologue thereof.
Claim 5
Dependent Claim
13 words
The process of claim 1 wherein the catalyst is metallic tin in powder.
Claim 6
Dependent Claim
19 words
The process of claim 1 wherein the catalyst is stannous oxide SnO or tin oxide containing divalent tin atom.
Claim 7
Dependent Claim
44 words
The process of claim 1 wherein the catalyst is selected from the group consisting of a tin salt of N-substituted mono-, bis- and poly-maleamic acid and a tin salt adduct obtained by coordinating a neutral ligand or water of crystallization to said tin salt.
Claim 8
Dependent Claim
62 words
The process of claim 1 wherein the catalyst is one or more of the tin salt of N-methylmaleamic acid, N-butyl-maleamic acid, N-dodecylmaleamic acid, N-stearylmaleamic acid, N-cyclohexylmaleamic acid, N-phenylmaleamic acid, N-tolylmaleamic acid, N,N'-(m- or p-phenylene)bis-maleamic acid, N,N'-(2,4-tolylene)bis-maleamic acid, N,N'-(4,4'-diphenylmethane)bis-maleamic acid, N,N'-(4,4'-diphenylether)bis-maleamic acid, N,N'-(4,4'-p-xylylenediphenyl)bis-maleamic acid and a tin salt adduct obtained by coordinating a neutral ligand or water of crystallization to said tin salt.
Claim 9
Dependent Claim
17 words
The process of claim 1 wherein catalyst is a tin salt of a weak organic carboxylic acid.
Claim 10
Dependent Claim
15 words
The process of claim 8 wherein the tin salt is stannous acetate or stannous 2-ethylhexanoate.
Claim 11
Dependent Claim
11 words
The process of claim 1 wherein the catalyst is tin halide.
Claim 12
Dependent Claim
15 words
The process of claim 10 wherein the tin halide is stannous chloride or stannic chloride.
Claim 13
Dependent Claim
28 words
The process of claim 1 wherein the starting N-substituted maleamic acid is produced in situ without isolation by the reaction of the corresponding maleic anhydride and primary amine.
Claim 14
Dependent Claim
21 words
The process of claim 2 wherein N-phenylmaleamicacid is produced in situ without isolation by the reaction of maleic anhydride with aniline.
Claim 15
Dependent Claim
38 words
The process of claim 1 wherein the organic solvent capable of forming water azeotrope is one or more of cyclohexane, benzene, toluene, ethylbenzene, xylene, cumene, chlorobenzene, anisole, dichloroethane, diethoxyethane, cyclohexanone, methyl ethyl ketone, methyl i-butyl ketone and trioxane.
Claim 16
Dependent Claim
29 words
The process of claim 1 wherein the organic aprotic polar solvent is one or more of dimethylformamide, dimethylacetamide, dimethylsulfoxide, sulfolane, methyl isobutyl ketone, γ-butyrolactone, hexamethylphosphoramide N-methylpyrrolidone, tetramethylurea and 1,3-dimethyl-2-imidazolidinone.
Claim 17
Dependent Claim
24 words
The process of claim 1 wherein the organic solvent capable of forming water azeotrope is xylene and the organic aprotic polar solvent is dimethylformamide.
Claim 18
Dependent Claim
23 words
The process of claim 1 wherein the concentration of the N-substituted maleamic acid in the reaction system is about 0.1 to 5 moles/l.
Claim 19
Dependent Claim
34 words
The process of claim 1 wherein the amount of the catalyst in the reaction system is in the range of 0.001 to 0.2 gram atom as tin per gram mole of the maleamic acid.
Claim 20
Dependent Claim
24 words
The process of claim 1 wherein the reaction and/or the purification of the reaction product are conducted in the presence of a polymerization inhibitor.
Claim 21
Dependent Claim
109 words
The process of claim 1 wherein N-phenyl maleamic acid is produced without isolation, in the concentration of the 0.5 to 3 mole per liter, by the reaction of maleic anhydride with aniline in the solvent of xylene, and after addition of dimethylforamide, said acid is in situ submitted to dehydration imidization under azeotropic distillation of the reaction generated water in the presence as the catalyst of metallic tin, tin oxide, a tin salt of said acid, a tin compound including stannous acetate, stannous 2-ethylhexanoate, stannous chloride or the mixture thereof in the amount of 0.005 to 0.02 gram atom of tin per mole of said acid, thereby producing N-phenylmaleimide.
References Cited (Backward Citations)
JPS5140078A
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JPS5546394A
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JPS6011465A
Cited
EP0165574A2
Cited
JPS6160647A
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JPS6263562A
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