Process for the manufacture of methyl limonitrile

Patent metadata

Field	Value
Publication number	US-9340750-B2
Application number	US-201314378551-A
Country	US
Kind code	B2
Filing date	Feb 11, 2013
Priority date	Feb 15, 2012
Publication date	May 17, 2016
Grant date	May 17, 2016

Abstract

The present invention is directed to a process for the manufacture of methyl limonitrile comprising a mixture of 3,7-dimethyl-2,6-nonadiene nitrile, 3,7-dimethyl-3,6-nonadiene nitrile and 7-methyl-3-methylene-6-nonene nitrile comprising the following steps: a) reacting 6-methyl-5-octen-2-one with cyano acetic acid and removing carbon dioxide and water, wherein the reaction and the removal of carbon dioxide and water are performed in the presence of a base and a co-base in an organic solvent, wherein the base is pyridine, wherein the co-base is 1,4-diamino butane, and wherein the organic solvent is a solvent which forms a heteroazeotrop with water; b) removing the solvent and pyridine of the reaction mixture obtained after having performed step a) or step c) by distillation to obtain a reaction mixture; c) isomerizing the reaction mixture obtained after having performed step a) or step b) to obtain an isomerized reaction mixture; whereby step b) can be performed before or after step c).

First claim

The invention claimed is:

1. A process for the manufacture of methyl limonitrile comprising a mixture of 3,7-dimethyl-2,6-nonadiene nitrile, 3,7-dimethyl-3,6-nonadiene nitrile and 7-methyl-3-methylene-6-nonene nitrile, wherein the process comprises the following steps:
a) reacting 6-methyl-5-octen-2-one with cyano acetic acid and removing carbon dioxide and water, wherein the reaction and the removal of carbon dioxide and water are performed in the presence of pyridine as a base and 1,4-diamino butane as a co-base in an organic solvent, and wherein the organic solvent is a solvent which forms a heteroazeotrop with water;
b) removing the solvent and pyridine of the reaction mixture obtained after having performed step a) or step c) by distillation to obtain a reaction mixture;
c) isomerizing the reaction mixture obtained after having performed step a) or step b) to obtain an isomerized reaction mixture; wherein
step b) can be performed before or after step c).

2. The process according to claim 1 , wherein the organic solvent is selected from the group consisting of toluene, benzene, ortho-xylene, meta-ylene, para-xylene, hexane, heptane, and any mixture thereof.

3. The process according to claim 1 , wherein the organic solvent is toluene.

4. The process according to claim 1 , wherein step b) is performed before step c).

5. The process according to claim 1 , wherein step b) comprises the step of recycling the solvent and pyridine which are removed from the reaction mixture back into step a).

6. The process according to claim 1 , further comprising the additional step which comprises extracting the isomerized reaction mixture with diluted acids to thereby form an organic phase containing the methyl limonitrile and an aqueous phase, separating the organic phase containing the methyl limonitrile from the aqueous phase, and washing the organic phase one or more times with deionized water.

7. The process according to claim 6 , comprising the additional step of back-extracting the aqueous phase with the solvent and removing the solvent.

8. The process according to claim 6 , further comprising the additional step of separating off coloured components and high boiling impurities from the organic phase.

9. The process according to claim 8 , further comprising the additional step of separating off the low boiling impurities.

10. The process according to claim 9 , wherein the low boiling impurities contain unconverted 6-methyl-5-octen-2-one, and wherein the process further comprises an additional step of recycling the 6-methyl-5-octen-2-one completely or partially back to the reaction of step a).

11. The process according to claim 1 , wherein the molar ratio of cyano acetic acid to 6-methyl-5-octen-2-one is in the range of 0.5 to 1.5 mol:1 mol.

12. The process according to claim 1 , wherein the amount of pyridine is in the range of 0.5 to 1.5 mol per mol of 6-methyl-5-octen-2-one.

13. The process according to claim 1 , wherein the amount of 1,4-diaminobutane is in the range of 0.005 to 0.15 mol per mol of 6-methyl-5-octen-2-one.

14. The process according to claim 1 , wherein the amount of solvent is in the range of 0.5 to 2 kg per kg of 6-methyl-5-octen-2-one.

15. The process according to claim 1 , wherein the ratio of 3,7-dimethyl-2,6-nonadiene nitrile is in the range of 60 to 90 norm-%, the ratio of 7-methyl-3-methylene-6-nonene nitrile is in the range of 0 to 10 norm-%, and the ratio of 3,7-dimethyl-3,6-nonadiene nitrile is in the range of from 10 to 30 norm-%, based on a total amount of 3,7-dimethyl-2,6-nonadiene nitrile, 7-methyl-3-methylene-6-nonene nitrile and 3,7-dimethyl-3,6-nonadiene nitrile being 100 norm-%.

16. The process according to claim 1 , wherein the ratio of 3,7-dimethyl-2,6-nonadiene nitrile is in the range of 70 to 85 norm-%, the ratio of 7-methyl-3-methylene-6-nonene nitrile is in the range of 0 to 5 norm-%, and the ratio of 3,7-dimethyl-3,6-nonadiene nitrile is in the range of from 15 to 25 norm-%, based on a total amount of 3,7-dimethyl-2,6-nonadiene nitrile, 7-methyl-3-methylene-6-nonene nitrile and 3,7-dimethyl-3,6-nonadiene nitrile being 100 norm-%.

17. The process according to claim 1 , wherein the ratio of 3,7-dimethyl-2,6-nonadiene nitrile is in the range of 76 to 83 norm-%, the ratio of 7-methyl-3-methylene-6-nonene nitrile is in the range of 0 to 2 norm-%, and the ratio of 3,7-dimethyl-3,6-nonadiene nitrile is in the range of from 17 to 22 norm-%, based on a total amount of 3,7-dimethyl-2,6-nonadiene nitrile, 7-methyl-3-methylene-6-nonene nitrile and 3,7-dimethyl-3,6-nonadiene nitrile being 100 norm-%.

18. The process according to claim 1 , wherein the ratio of 3,7-dimethyl-2,6-nonadiene nitrile is around 80 norm-%, the ratio of 7-methyl-3-methylene-6-nonene nitrile is around 0 norm-%, and the ratio of 3,7-dimethyl-3,6-nonadiene nitrile is around 20 norm-%, based on a total amount of 3,7-dimethyl-2,6-nonadiene nitrile, 7-methyl-3-methylene-6-nonene nitrile and 3,7-dimethyl-3,6-nonadiene nitrile being 100 norm-%.

19. A process for the manufacture of methyl limonitrile of olfactive quality comprising a mixture of 3,7-dimethyl-2,6-nonadiene nitrile, 3,7-dimethyl-3,6-nonadiene nitrile and 7-methyl-3-methylene-6-nonene nitrile, wherein the process comprises the following steps:
a) reacting 6-methyl-5-octen-2-one with cyano acetic acid and removing carbon dioxide and water, wherein the reaction and the removal of carbon dioxide and water are performed in the presence of pyridine as base and 1,4-diamino butane as co-base in toluene as organic solvent;
b) removing the toluene and the pyridine by distillation to obtain a reaction mixture;
c) isomerizing the reaction mixture obtained after having performed step b) to obtain an isomerized reaction mixture;
d) extracting the isomerized reaction mixture with diluted acids whereby an organic phase and an aqueous phase are formed, separating the organic phase containing the methyl limonitrile from the aqueous phase, and washing the organic phase one or more times with deionized water;
d-2) optionally back-extracting the aqueous phase obtained in step d) with toluene and afterwards removing the toluene, whereby the thus removed toluene is optionally recycled into step d-2);
e) separating off coloured components and high boiling impurities from the organic phase obtained in step d);
f) separating off low boiling impurities containing unconverted 6-methyl-5-octen-2-one from the distillate obtained in step e); and
f2) optionally recycling the 6-methyl-5-octen-2-one back into step a).

Assignees

• Dsm Ip Assets Bv

Inventors

• Beumer Raphael
• Bonrath Werner
• Dorn Silke
• Wildermann Angela

Classifications

• C11B9/0023 Primary

  containing nitrogen as the only heteroatom · CPC title

• C07C253/30 Primary

  by reactions not involving the formation of cyano groups · CPC title

• C07C255/07

  Mononitriles · CPC title