Method for purifying n-substituted maleimide

Patent metadata

Field	Value
Publication number	US-10899708-B2
Application number	US-201816615015-A
Country	US
Kind code	B2
Filing date	Aug 29, 2018
Priority date	Dec 21, 2017
Publication date	Jan 26, 2021
Grant date	Jan 26, 2021

Abstract

The present invention relates to a method for purifying N-substituted maleimide. More specifically, the present invention, without performing a water washing process, enables to remove organic-acid-impurities which are difficult to remove through distillation because of having similar boiling points to the N-substituted maleimide compound by utilizing solubility of organic-acid-impurities in an organic solvent used in the preparing process of the maleimide compound, and thereby, without producing washing wastewater, ensuring removal efficiency of the organic-acid-impurities equal to or similar to an N-substituted maleimide compound subjected to a water washing process.

First claim

The invention claimed is:

1. A method for purifying N-substituted maleimide, comprising:
1) a step of preparing an N-substituted maleimide solution by reacting with maleic anhydride and a primary amine in the presence of an organic solvent and a catalyst; and
2) a step of cooling the N-substituted maleimide solution to 50° C. to 60° C. to precipitate a solidified organic acid, removing the solidified organic acid by filtering.

2. The method for purifying the N-substituted maleimide of claim 1 , wherein the organic solvent is at least one selected from the group consisting of benzene, toluene, xylene, o-xylene, ethylbenzene, isopropylbenzene, cumene, mesitylene, tert-butylbenzene, pseudocumene, trimethylhexane, octane, tetrachloroethane, nonane, chlorobenzene, ethylcyclohexane, m-dichlorobenzene, sec-butylbenzene, p-dichlorobenzene, decane, p-cymene, o-dichlorobenzene, butylbenzene, decahydronaphthalene, tetrahydronaphthalene, dodecane, naphthalene and cyclohexylbenzene.

3. The method for purifying the N-substituted maleimide of claim 1 , wherein the organic acid is at least one selected from the group consisting of fumaric acid (FA), maleic acid (MA), N-phenyl maleamic acid (PMA), N-phenyl maleimide (PMI), N-(2,5-dioxo-1-phenyl-3-pyrrolidinyl)-N-phenyl maleamic acid) (PPMA), N-(2,5-dioxo-1-phenyl-3-pyrrolidinyl)-N-phenyl fumaranilic acid) (PPFA) and 2-anilino-N-phenyl succinimide (APSI).

4. The method for purifying the N-substituted maleimide of claim 1 , wherein a boiling point of the organic acid is no more than 30° C. lower and no more than 40° C. higher than a boiling point of the N-substituted maleimide.

5. The method for purifying the N-substituted maleimide of claim 1 , wherein an amount of the organic acid contained in the N-substituted maleimide solution of step 1) is 0.1 wt % to 5.0 wt %.

6. The method for purifying the N-substituted maleimide of claim 1 , wherein an amount of the organic acid contained in the N-substituted maleimide solution after carrying out step 2) is 0.03 wt % to 0.1 wt %.

7. The method for purifying the N-substituted maleimide of claim 1 , further comprising a step of separating a catalyst from the N-substituted maleimide solution, and the separating the catalyst is carried out through the filtering in step 2), or through high-temperature filtration at 100° C. to 140° C. before carrying out step 2).

8. The method for purifying the N-substituted maleimide of claim 1 , wherein the catalyst is a zirconium (IV) hydrogen phosphate (Zr(H 2 PO 4 ) 2 ) solid-acid-catalyst.

9. The method for purifying the N-substituted maleimide of claim 1 , further comprising a step of distilling the N-substituted maleimide solution after carrying out step 2).

10. The method for purifying the N-substituted maleimide of claim 1 , wherein a water washing process is not carried out.

11. The method for purifying the N-substituted maleimide of claim 1 , wherein the primary amine is at least one selected from the group consisting of methylamine, ethylamine, n-propylamine, iso-propylamine, n-butylamine, sec-butylamine, iso-butylamine, tert-butylamine, n-hexylamine, n-octylamine, n-decylamine, n-dodecylamine, cyclohexylamine, and aniline.

12. The method for purifying the N-substituted maleimide of claim 1 , wherein the N-substituted maleimide is at least one selected from the group consisting of: N-alkyl maleimide such as N-methyl maleimide, N-ethyl maleimide, N-hexyl maleimide, N-octyl maleimide, or N-dodecyl maleimide; N-benzyl maleimide; N-cycloalkyl maleimide such as N-cyclohexyl maleimide; N-phenyl maleimide; and N-substituted phenyl maleimide, in which a phenyl group is substituted with a nitro group, an alkoxy group, an alkyl group, a carboxyl group, a hydroxyl group, or a halogen group, such as N-nitrophenyl maleimide, N-methoxyphenyl maleimide, N-methylphenyl maleimide, N-carboxyphenyl maleimide, N-hydroxyphenyl maleimide, N-chlorophenyl maleimide, N-dimethylphenyl maleimide, N-dichlorophenyl maleimide, N-bromophenyl maleimide, N-dibromophenyl maleimide, N-trichlorophenyl maleimide, or N-tribromophenyl maleimide.

Assignees

• Lg Chemical Ltd

Inventors

• Cheon Joo Young
• Choi Jun Seon
• Kim Ji Yeon
• Kang Ki Hyuk

Classifications

• C08F8/30

  Introducing nitrogen atoms or nitrogen-containing groups · CPC title

• C07D207/448 Primary

  with only hydrogen atoms or radicals containing only hydrogen and carbon atoms directly attached to other ring carbon atoms, e.g. maleimide · CPC title

• C07D207/444 Primary

  having two doubly-bound oxygen atoms directly attached in positions 2 and 5 · CPC title