Method for preparing 3-aminomethyl-3,5,5-trimethyl cyclohexylamine

• US 9,624,162 B2
• Filed: 12/07/2012
• Issued: 04/18/2017
• Est. Priority Date: 12/07/2012
• Status: Active Grant

• Current Assignee: Wanhua Chemical Group Co., Ltd. (Wanhua Industrial Group Company Limited)
• Original Assignee: Wanhua Chemical Group Co., Ltd. (Wanhua Industrial Group Company Limited)
• Inventors: Chen, Changsheng, Jiang, Jinke, Chen, Zhongying, Cui, Jiaoying, Wang, Jing, Li, Fuguo, Lv, Chengge, Zhao, Wenjuan, Li, Yuan, Hua, Weiqi
• Primary Examiner(s): Katakam, Sudhakar
• Assistant Examiner(s): Sawyer, Jennifer C
• Application Number:
  US14/648,533
• Publication Number:
  US 20150315133A1
• Time in Patent Office: 1,593 Days
• Field of Search: None
• CPC Class Codes: C07C 209/48 by reduction of nitriles
• CPC Class Codes: C07C 209/52 by reduction of imines or imino-ethers C07C209/24 takes precedence
• CPC Class Codes: C07C 211/36 containing at least two amino groups bound to the carbon skeleton
• CPC Class Codes: C07C 253/30 by reactions not involving the formation of cyano groups
• CPC Class Codes: C07C 255/46 to carbon atoms of non-condensed rings
• CPC Class Codes: C07C 2601/14 The ring being saturated

Abstract

The present invention provides a method for preparing 3-aminomethyl-3,5,5-trimethyl cyclohexylamine. The method comprises: a) reacting 3-cyano-3,5,5-trimethyl cyclohexanone with excess primary amine as well as removing the water generated from the reaction, so that IPN is substantially converted into imine compounds; b) in the presence of an ammonolysis catalyst, mixing the product of step a) with liquid ammonia, making the imine compound perform ammonolysis reaction to generate 3-cyano-3,5,5-trimethyl cyclohexylimine and the primary amine; and c) in the presence of hydrogen and a hydrogenation catalyst, hydrogenating 3-cyano-3,5,5-trimethyl cyclohexylimine obtained in step b) to obtain 3-aminomethyl-3,5,5-trimethyl cyclohexylamine. The method of the present invention avoids the generation of 3,5,5-trimethyl cyclohexanol and 3-aminomethyl-3,5,5-trimethyl cyclohexanol as the major by-products in the prior art, thereby improving the yield of 3-aminomethyl-3,5,5-trimethyl cyclohexylamine.

Claims

1. A method for preparing 3-aminomethyl-3,5,5-trimethyl cyclohexylamine (IPDA), comprising the following steps:

a) reacting 3-cyano-3,5,5-trimethyl cyclohexanone (IPN) with excess primary amine as well as removing generated water, so that IPN is converted into imine compounds;

b) in the presence of an ammonolysis catalyst, mixing the product of step a) with liquid ammonia, making the imine compounds perform ammonolysis reaction to generate 3-cyano-3,5,5-trimethyl cyclohexylimine (IPNI) and the primary amine, wherein step b) is carried out at a temperature ranging from 20 to 200°

C. and under a pressure ranging from 10 to 30 MPa; and

c) in the presence of hydrogen and the hydrogenation catalyst, hydrogenating IPNI obtained in step b) to obtain IPDA.

2. The method according to claim 1, characterized in that the primary amine in step a) is a mono-amine or a diamine selected from the group consisting of C_1-30 alkyl amines, C_3-30 cycloalkyl amines, C_6-30 aryl amines, and C_7-30 arylalkyl amines.

3. The method according to claim 2, characterized in that the primary amine is a primary amine having a boiling point between 110°

C. and 235°

C.

4. The method according to claim 1, characterized in that the primary amine in step a) is IPDA.

5. The method according to claim 1, characterized in that the mole ratio of the total amino groups (—

NH₂) of the primary amine to IPN in step a) is in the range of 1-20.

6. The method according to claim 1, characterized in that water is removed by using methods of adsorption, extraction or distillation in step a).

7. The method according to claim 6, characterized in that the distillation method is a method of distillation under a reduced pressure.

8. The method according to claim 7, characterized in that step a) is carried out under the pressure of 100 kPa or less.

9. The method according to claim 1, characterized in that step a) is carried out at 20-150°

C.

10. The method according to claim 1, characterized in that the water content of the product obtained in step a) is 300 ppm or less.

11. The method according to claim 1, characterized in that the mole ratio of the liquid ammonia to IPN used as a raw material in step a) is 5-200.

12. The method according to claim 1, characterized in that a fixed bed reactor is used in step c), wherein the mole ratio of hydrogen to isophorone imine is 10-100.

13. The method according to claim 4, characterized in that at least a portion of IPDA obtained in step c) is returned to step a) and acts as the primary amine to perform imidization reaction with IPN.

14. The method according to claim 1, characterized in that the primary amine is not IPDA, and the method further comprises step d):

separating the primary amine from IPDA in the product obtained in step c) by rectification, wherein the primary amine is returned to step a) for recycling use.

15. The method according to claim 1, characterized in that step b) is carried out at a temperature of 50-150°

C. and under a pressure of 10-20 MPa.

16. The method according to claim 1, characterized in that the ammonolysis catalyst used in step b) is an acid metal oxide selected from the group consisting of γ

-alumina, titania, zirconia, silica, and zeolite.

17. The method according to claim 1, characterized in that step c) is carried out at a temperature of 100-200°

C. and under a pressure of 10-30 MPa.

18. The method according to claim 1, characterized in that the hydrogenation catalyst used in step c) is selected from Raney metal catalyst.

19. The method according to claim 2, characterized in that the primary amine in step a) is selected from the group consisting of methylamine, ethylamine, propylamine, butylamine, ethylenediamine, propylenediamine, butanediamine, hexamethylenediamine, and aniline.

20. The method according to claim 5, characterized in that the mole ratio of the total amino groups (—

NH₂) of the primary amine to IPN in step a) is in the range of 1-10.

21. The method according to claim 10, characterized in that the water content of the product obtained in step a) is 200 ppm or less.

22. The method according to claim 10, characterized in that the water content of the product obtained in step a) is 100 ppm or less.

23. The method according to claim 11, characterized in that the mole ratio of the liquid ammonia to IPN used as a raw material in step a) is 10-100.

24. The method according to claim 15, characterized in that step b) is carried out at the temperature of 80-120°

C. and under the pressure of 10-15 MPa.

25. The method according to claim 18, characterized in that the hydrogenation catalyst used in step c) is selected from Raney cobalt or Raney nickel.