Process for the direct amination of alcohols using ammonia to form primary amines by means of a xantphos catalyst system
View Patent ↗The present invention relates to a chemocatalytic liquid-phase process for the direct one-stage amination of alcohols to primary amines by means of ammonia in high yields using a catalyst system containing at least one transition metal compound and a xantphos ligand.
1. A process for preparing a primary amine, comprising:
contacting a solution of an alcohol in a fluid, nongaseous phase,
with free ammonia, an ammonia-liberating compound, or both, and a homogeneous catalyst system comprising carbonylchlorohydrido[9,9-dimethyl-4,5-bis(diphenylphosphino)xantheno]ruthenium(II)] as a xantphos ligand; and
optionally isolating the primary amine obtained in the contacting.
2. The process according to claim 1 ,
wherein the alcohol is an aliphatic, linear ω-hydroxycarboxylic acid having a carbon chain comprising at least 8 carbon atoms.
3. The process according to claim 1 ,
wherein the alcohol has a concentration of from 0.1 to 1000 mmol/l, based on the fluid phase.
4. The process according claim 1 ,
wherein the contacting comprises contacting with liquid or supercritical ammonia, with a solution of ammonium salts in a solvent, or both.
5. The process according to claim 1 ,
wherein in the contacting, the ammonia has a molar ratio to hydroxyl groups in the alcohol of at least 5:1.
6. The process according to claim 1 ,
wherein the contacting is carried out at a pressure of from 1 to 1000 bar.
7. The process according to claim 1 ,
wherein the contacting is carried out in a temperature range of from 80 to 220° C.
8. The process according claim 1 ,
wherein a volume ratio of a liquid phase to a gas phase in the contacting is at least 0.05.
9. The process according to claim 1 ,
wherein the process is carried out in the absence of hydrogen.
10. The process according to claim 1 , wherein the alcohol has a concentration of from 0.1 to 100 mmol/l based on the fluid phase.
11. The process according to claim 1 , wherein the alcohol has a concentration of from 0.1 to 10 mmol/l based on the fluid phase.
12. The process according to claim 1 , wherein in the contacting, the ammonia has a molar ratio to hydroxyl groups in the alcohol of at least 50:1.
13. The process according to claim 1 , wherein in the contacting, the ammonia has a molar ratio to hydroxyl groups in the alcohol of at least 500:1.
14. The process according to claim 1 , wherein the contacting is carried out at a pressure of from 5 to 500 bar.
15. The process according to claim 1 , wherein the contacting is carried out at a pressure of from 5 to 20 bar.
16. The process according to claim 1 , wherein the contacting is carried out in a temperature range of from 100 to 200° C.
17. The process according to claim 1 , wherein the contacting is carried out in a temperature range of from 120 to 170° C.
18. The process according to claim 1 , wherein a volume ratio of a liquid phase to a gas phase in the contacting is greater than or equal to 0.1.