Process for the isomerisation of an exo double bond

Patent metadata

Field	Value
Publication number	US-9416082-B2
Application number	US-201414768222-A
Country	US
Kind code	B2
Filing date	Feb 7, 2014
Priority date	Feb 11, 2013
Publication date	Aug 16, 2016
Grant date	Aug 16, 2016

Abstract

The present invention concerns a process for the isomerization of an exo double bond toward an endo double bond being performed in the presence of a catalyst system comprising palladium (Pd) or platinum (Pt) and molecular hydrogen or a hydrogen source.

First claim

What is claimed is:

1. A process for the preparation of a compound of formula (I)

wherein R, R 1 and R 2 , simultaneously or independently, represent a hydrogen atom or a linear or branched C 1-5 alkyl group; R 3 represents a linear or branched C 1-5 alkyl or alkenyl group;

by the isomerisation of the corresponding compound of the formula (II)

wherein R, R 1 , R 2 and R 3 have the same meaning as in formula (I);

said isomerization being performed in the presence of molecular hydrogen or a hydrogen source, and a catalyst system comprising a metal selected from palladium (Pd) or platinum (Pt).

2. A process according to claim 1 , characterized in that said R 1 represents a hydrogen atom.

3. A process according to claim 1 , characterized in that said R 2 represents a C 1-5 alkyl group and said R represents a hydrogen atom.

4. A process according to claim 1 , characterized in that said compound of formula (I) is 2,3-dimethylbut-2-enal or 2-methylpenta-2,4-dienal.

5. A process according to claim 1 , characterized in that said metal is supported on carbon or aluminum oxide.

6. A process according to claim 5 , characterized in that said hydrogen source is tetralin, formic acid, limonene or cyclohexanol.

7. A process according to claim 1 , characterized in that said molecular hydrogen is mixed with nitrogen or argon in a volume ratio comprised between 1/1 to 0.01/1.

8. A process according to claim 1 , characterized in that said process is a continuous process.

9. A process for the preparation of a compound of formula (I)

wherein R, R 1 and R 2 , simultaneously or independently, represent a hydrogen atom or a linear or branched C 1-5 alkyl group; R 3 represents a linear or branched C 1-5 alkyl or alkenyl group which consists of the isomerisation of the corresponding compound of the formula (II)

wherein R, R 1 , R 2 and R 3 have the same meaning as in formula (I) in the presence of a catalyst system of metal selected amongst palladium (Pd) or platinum (Pt); and molecular hydrogen or a hydrogen source.

10. A process according to claim 9 , characterized in that said R 1 represents a hydrogen atom.

11. A process according to claim 9 , characterized in that said R 2 represents a C 1-5 alkyl group and said R represents a hydrogen atom.

12. A process according to claim 9 , characterized in that said compound of formula (I) is 2,3-dimethylbut-2-enal or 2-methylpenta-2,4-dienal.

13. A process according to claim 9 , characterized in that said metal is supported on carbon or aluminum oxide.

14. A process according to claim 13 , characterized in that said hydrogen source is tetralin, formic acid, limonene or cyclohexanol.

15. A process according to claim 9 , characterized in that said molecular hydrogen is mixed with nitrogen or argon in a volume ratio comprised between 1/1 to 0.01/1.

16. A process according to claim 9 , characterized in that said process is a continuous process.

Assignees

• Firmenich & Cie

Inventors

• Boshra Ramez
• Vanhessche Koenraad
• Alexander Anatoly

Classifications

• C07C2601/10

  the ring being unsaturated · CPC title

• C07C45/67 Primary

  by isomerisation; by change of size of the carbon skeleton · CPC title

• C07C2601/14

  The ring being saturated · CPC title

• C07C49/597

  of a five-membered ring · CPC title

• C07C2101/14

  Chemistry & Metallurgy · mapped topic