Method for producing 2-substituted 4-hydroxy-4-methyl-tetrahydropyrans in a reactor cascade

Patent metadata

Field	Value
Publication number	US-9688650-B2
Application number	US-201414787285-A
Country	US
Kind code	B2
Filing date	Apr 28, 2014
Priority date	Apr 29, 2013
Publication date	Jun 27, 2017
Grant date	Jun 27, 2017

Abstract

The invention relates to a method for producing 2-substituted 4-hydroxy-4-methyltetrahydropyrans.

First claim

The invention claimed is:

1. A process for the preparation of a 2-substituted 4-hydroxy-4-methyltetrahydropyran of the formula (I)

in which
R 1 is a straight-chain or branched C 1 -C 12 -alkyl, straight-chain or branched C 2 -C 12 -alkenyl, unsubstituted or C 1 -C 12 -alkyl and/or C 1 -C 12 -alkoxy substituted cycloalkyl having in total 3 to 20 carbon atoms or unsubstituted or C 1 -C 12 -alkyl and/or C 1 -C 12 -alkoxy substituted aryl having in total 6 to 20 carbon atoms,
comprising reacting 3-methylbut-3-en-1-ol of the formula (III)

with an aldehyde of the formula (IV)
R 1 —CHO  (IV)

where R 1 in the formula (IV) has the meaning given above,
in the presence of an acidic catalyst, wherein the reaction takes place in an arrangement consisting of n reactors connected in series, n being a natural number from 2 to 8;
wherein a part stream is removed between the first and last reactor in the flow direction and is fed into a reactor positioned upstream of the removal point.

2. The process according to claim 1 , wherein the reaction takes place continuously.

3. The process according to claim 1 , wherein the reaction takes place in the presence of a solvent.

4. The process according to claim 1 , wherein a part stream is removed from the reactor discharge of the first and/or second reactor in the flow direction and is returned at least partially to the first reactor in the flow direction via an external recirculation.

5. The process according to claim 4 , wherein the part stream of the reactor discharge is stripped off from the first reactor and is returned to the first reactor in the flow direction via an external circuit.

6. The process according to claim 1 , wherein heat is withdrawn from the part stream before it is fed into a reactor positioned upstream of the removal point.

7. The process according to claim 1 , wherein at least the first reactor in the flow direction is operated isothermally.

8. The process according to claim 1 , wherein the first and second reactor in the flow direction is operated in each case isothermally.

9. The process according to claim 1 , wherein the (n−1)th reactor in the flow direction is operated isothermally.

10. The process according to claim 1 , wherein heat is withdrawn from the reactor discharge from at least one of the first to (n−1)th reactors before introducing it into the following reactor in the flow direction.

11. The process according to claim 1 , wherein at least the last reactor in the flow direction is operated without recirculation of the reactor discharge.

12. The process according to claim 1 , wherein n is 2 or 3.

13. The process according to claim 1 , wherein the reaction at least in the last reactor in the flow direction is carried out adiabatically.

14. The process according to claim 1 , wherein a reactor arrangement is used for the reaction which comprises at least one fixed-bed reactor.

15. The process according to claim 1 , wherein a reactor arrangement is used for the reaction which comprises at least one reactor with an internally arranged heat exchanger.

16. The process according to claim 1 , wherein R 1 is isobutyl or phenyl.

17. The process according to claim 1 , wherein the reaction takes place in the presence of an acidic catalyst which is selected from the group consisting of hydrochloric acid, sulfuric acid, methanesulfonic acid, p-toluenesulfonic acid and strongly acidic cation exchangers.

18. The process according to claim 13 , wherein the reaction is carried out in the presence of a strongly acidic cation exchanger.

19. The process according to claim 1 , wherein the alcohol of the formula (III) and the aldehyde of the formula (IV) are used in a molar ratio in the range from 0.7:1 to 2:1.

20. The process according to claim 1 , wherein the alcohol of the formula (III) and the aldehyde of the formula (IV) are reacted in the presence of 3% by weight to 15% by weight of water based on the amount of the reaction mixture consisting of the components of the formulae (III) and (IV) and water.

21. The process according to claim 1 , wherein the reaction is carried out at a temperature in the range from 0° C. to 70° C.

22. The process according to claim 1 , wherein the reaction is carried out at a pressure in the range from 1 bar to 15 bar.

Assignees

• Basf Se

Inventors

• Stork Timon
• Beck Karl
• Ebel Klaus
• Bey Oliver
• Gralla Gabriele

Classifications

• C07D309/10 Primary

  Oxygen atoms · CPC title