Method for purifying N-substituted maleimide

Patent metadata

Field	Value
Publication number	US-11345661-B2
Application number	US-201816336084-A
Country	US
Kind code	B2
Filing date	Jul 9, 2018
Priority date	Dec 26, 2017
Publication date	May 31, 2022
Grant date	May 31, 2022

Abstract

The present invention relates to a method for purifying N-substituted maleimide. More particularly, the present invention adopts an evaporation apparatus, which can previously remove impurities having higher boiling points than the N-substituted maleimide after removing an organic solvent from an N-substituted maleimide resulting solution, thereby achieving effects of minimizing the pressure loss and polymerization loss, and obtaining high-purity N-substituted maleimide.

First claim

The invention claimed is:

1. A method for purifying N-substituted maleimide, comprising:
1) performing a primary purification by introducing an N-substituted maleimide solution into a first distillation column and removing an organic solvent by distilling to produce an N-substituted maleimide residue; and
2) performing a secondary purification by introducing, into an evaporation apparatus, the N-substituted maleimide residue, and removing impurities which have higher boiling points than the N-substituted maleimides.

2. The method for purifying N-substituted maleimide of claim 1 , wherein the N-substituted maleimide solution comprises the organic solvent, an unreacted maleic anhydride, an organic acid impurity, and an oligomer in which the N-substituted maleimide is polymerized.

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

4. The method for purifying N-substituted maleimide of claim 1 , wherein the organic solvent comprises 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.

5. The method for purifying N-substituted maleimide of claim 1 , wherein an operating pressure of a first distillation column in the primary purification is from 20 to 80 torr.

6. The method for purifying N-substituted maleimide of claim 1 , wherein an operating temperature of a reboiler at the bottom of the first distillation column in the primary purification is from 170 to 220° C.

7. The method for purifying N-substituted maleimide of claim 1 , wherein the evaporation apparatus in the secondary purification is at least one selected from the group consisting of a thin film evaporator, a falling film evaporator, and a flash drum.

8. The method for purifying N-substituted maleimide of claim 1 , wherein the impurities, which have higher boiling points than the N-substituted maleimide, are at least one selected from the group consisting of N-(2,5-dioxo-1-phenyl-3-pyrrolidinyl)-N-phenyl maleamic acid) (PPMA), N-(2,5-dioxo-1-phenyl-3-pyrrolidinyl)-N-phenylfumaramic acid (PPFA), and 2-anilino-N-phenyl succinimide (APSI).

9. The method for purifying N-substituted maleimide of claim 1 , wherein an operating pressure of the evaporation apparatus in the secondary purification is from 5 to 30 torr.

10. The method for purifying N-substituted maleimide of claim 1 , wherein an operating pressure of the evaporation apparatus in the secondary purification is from 5 to 10 torr.

11. The method for purifying N-substituted maleimide of claim 1 , wherein an operating temperature of the evaporation apparatus in the secondary purification is from 100 to 180° C.

12. The method for purifying N-substituted maleimide of claim 1 , wherein the N-substituted maleimide residue in the evaporation apparatus in the secondary purification resides in the apparatus for from 20 seconds to 5 minutes.

13. The method for purifying N-substituted maleimide of claim 1 , further comprising, after the second purification:
3) performing a tertiary purification by introducing and distilling, in a second distillation column, the N-substituted maleimide distillate from which the high-boiling-point impurities are removed.

14. The method for purifying N-substituted maleimide of claim 13 , wherein an operating pressure of the second distillation column in the tertiary purification is from 20 to 80 torr.

15. The method for purifying N-substituted maleimide of claim 13 , wherein a reboiler at the bottom of the second distillation column in the tertiary purification is operated at a temperature from 190 to 230° C.

16. The method for purifying N-substituted maleimide of claim 1 , wherein a polymerization loss ratio through the method for purifying N-substituted maleimide is 10% or less at 190° C.

17. The method for purifying N-substituted maleimide of claim 1 , wherein the polymerization loss ratio through the purification method for N-substituted maleimide is 30% or less at 210° C.

18. The method for purifying N-substituted maleimide of claim 1 , wherein the purity through the method for purifying N-substituted maleimide is 95% or more.

19. The method for purifying N-substituted maleimide of claim 1 , wherein the N-substituted maleimide comprises 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

• Kim Eun Kyo
• Lee Jeong Seok
• Kim Mi Kyung
• Cheon Joo Young

Classifications

• C07D207/444 Primary

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

• C08F222/40

  Imides, e.g. cyclic imides · CPC title

• C08F6/28

  Purification · 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

• C08F2/01

  characterised by special features of the polymerisation apparatus used · CPC title