Method for preparing aliphatic isocyanate

Patent metadata

Field	Value
Publication number	US-10654796-B2
Application number	US-201716469224-A
Country	US
Kind code	B2
Filing date	Dec 6, 2017
Priority date	Dec 29, 2016
Publication date	May 19, 2020
Grant date	May 19, 2020

Abstract

Provided is a method capable of preparing high-purity aliphatic isocyanate, particularly, xylylene isocyanate in a high yield in a simple manner without an additional separate process, wherein when aliphatic isocyanate is prepared using phosgene, a side-reaction inhibitor capable of inhibiting side-reactions is introduced during phosgenation.

First claim

The invention claimed is:

1. A method for preparing aliphatic isocyanate, comprising: reacting aliphatic amine or a salt thereof with phosgene in the presence of a compound of the following Chemical Formula 1:

in Chemical Formula 1, R 1 to R 4 are each independently a C 1˜12 hydrocarbyl group,
X is hydrogen, a hydroxyl group, or an acetamido group, and
Y is an oxyl (O⋅) group or a C 1˜20 hydrocarbyloxy group.

2. The method of claim 1 , wherein R 1 to R 4 in Chemical Formula 1 are each independently a C 1˜4 alkyl group, X is hydrogen, a hydroxyl group, or an acetamido group, and Y is an oxyl group.

3. The method of claim 1 , wherein the compound of Chemical Formula 1 is selected from the group consisting of 2,2,6,6-tetramethylpiperidine 1-oxyl, 4-hydroxy-2,2,6,6-tetramethylpiperidine 1-oxyl, and 4-acetamido-2,2,6,6-tetramethylpiperidine 1-oxyl.

4. The method of claim 1 , wherein the compound of Chemical Formula 1 is used in a molar ratio of 0.05 to 2 with respect to 100 moles of the aliphatic amine or the salt thereof.

5. The method of claim 1 , wherein the reacting with phosgene is performed in an organic solvent having a boiling point of 120° C. or higher.

6. The method of claim 1 , wherein the reacting with phosgene is performed in an organic solvent selected from the group consisting of an aromatic hydrocarbon-based organic solvent, an ester-based organic solvent, and a mixture thereof.

7. The method of claim 1 , comprising a first step of introducing the aliphatic amine or the salt thereof to a mixture which is prepared by dissolving the compound of Chemical Formula 1 and 50 wt % to 80 wt % of the total phosgene in an organic solvent at a temperature of −15° C. to −10° C.; and a second step of introducing and reacting the remainder of phosgene at 120° C. to 150° C. after completing the introduction of the aliphatic amine or the salt thereof.

8. The method of claim 7 , wherein the compound of Chemical Formula 1 is used in a molar ratio of 0.05 to 0.5 with respect to 100 moles of the aliphatic amine or the salt thereof.

9. The method of claim 1 , further comprising the step of preparing the salt of the aliphatic amine by reacting the aliphatic amine with hydrochloric acid or carbonic acid at a temperature of 30° C. or lower, before reacting with phosgene, wherein the reacting with phosgene is performed at 120° C. to 150° C.

10. The method of claim 9 , further comprising the step of preparing aliphatic amine-hydrochloride by reacting the aliphatic amine with hydrochloric acid in an organic solvent containing the compound of Chemical Formula 1 at a temperature of 30° C. or lower, before reacting with phosgene, wherein the compound of Chemical Formula 1 is used in a molar ratio of 0.15 to 0.8 with respect to 100 moles of the aliphatic amine or the salt thereof, and a concentration of the aliphatic amine in the organic solvent is 8 volume % to 10 volume %.

11. The method of claim 1 , wherein the aliphatic amine is xylylene diamine.

12. The method of claim 1 , wherein purity of the aliphatic isocyanate is 97% or more, and a content of monoisocyanate including ethylbenzyl isocyanate and chloromethylbenzyl isocyanate is 2.15% or less.

Assignees

• Hanwha Chemical Corp

Inventors

• Park Ju Young
• Ahn Cho Hee
• Chae Seung Won
• Kim Jeon Sik
• Cho Sang Hyun

Classifications

• C07C263/18

  Separation; Purification; Stabilisation; Use of additives · CPC title

• C07C263/10 Primary

  by reaction of amines with carbonyl halides, e.g. with phosgene · CPC title

• C07D211/06

  having no double bonds between ring members or between ring members and non-ring members · CPC title

• C07C265/08

  the carbon skeleton containing rings · CPC title

• C07D211/94 Primary

  Oxygen atom, e.g. piperidine N-oxide · CPC title