Process for the integrated preparation of 2-substituted 4-hydroxy-4-methyltetrahydropyrans and of 2-substituted 4-Methyltetrahydropyrans

• US 9,139,549 B2
• Filed: 10/14/2013
• Issued: 09/22/2015
• Est. Priority Date: 10/15/2012
• Status: Active Grant

• Current Assignee: BASF SE
• Original Assignee: BASF SE
• Inventors: Stork, Timon, Rder, Oskar, Ebel, Klaus, Pelzer, Ralf, Krause, Wolfgang, Beck, Karl
• Primary Examiner(s): Jarrell, Noble
• Assistant Examiner(s): MAURO, JOHN MATTHEW
• Application Number:
  US14/053,020
• Publication Number:
  US 20140107352A1
• Time in Patent Office: 708 Days
• Field of Search: 549/356, 549/416
• US Class Current: 1/1
• CPC Class Codes: C07D 309/04 with only hydrogen atoms, hydrocarbon or substituted hydrocarbon radicals, directly attached to ring carbon atoms
• CPC Class Codes: C07D 309/10 Oxygen atoms

Abstract

The present invention relates to a process for the integrated preparation of 2-substituted 4-hydroxy-4-methyltetrahydropyrans and of 2-substituted 4-methyltetrahydropyrans.

Claims

1. A process for preparing 2-substituted 4-hydroxy-4-methyltetrahydropyrans of formula (I) and of 2-substituted 4-methyltetrahydropyrans of formula (II)

2. The process according to claim 1, where R¹ is isobutyl or phenyl.

3. The process according to claim 1, in which the reaction in step a) 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.

4. The process according to claim 3, in which the reaction in step a) is carried out in the presence of a strongly acidic cation exchanger.

5. The process according to claim 4, in which the reaction in step a) is carried out in the presence of a strongly acidic cation exchanger and in the presence of added water.

6. The process according to claim 1, where, in step b), the reaction product from step a) is subjected to a distillative separation.

7. The process according to claim 6, where, for the separation in step b), a device is used which comprises

a feed column with rectifying section positioned above the feed point, and stripping section positioned below the feed point,

an upper combining column communicating with the upper end of the rectifying section, and a lower combining column communicating with the lower end of the stripping section, and

a take-off column communicating with the upper combining column and the lower combining column.

8. The process according to claim 6, where the distillative separation takes place in an arrangement of distillation columns which comprises a dividing-wall column or an interconnection of at least two thermally coupled conventional distillation columns.

9. The process according to claim 6, where, for the distillative separation of the reaction product from step a), an arrangement of distillation columns is used which comprises an upstream conventional distillation column and a downstream dividing-wall column or a downstream interconnection of two thermally coupled conventional distillation columns.

10. The process according to claim 9, where, for the distillative separation in step b),

the reaction mixture from step a) is subjected firstly to a separation in a conventional distillation column, where a first top product is obtained which comprises the compounds (V.1), (V.2) and (V.3) and the dioxane compound (VI) and comprises essentially no compounds of formula (I), and a first bottom product is obtained which comprises compounds of formula (I), and

the first bottom product is subjected to a separation in a dividing-wall column or in an interconnection of two thermally coupled conventional distillation columns, where a second top product is obtained which comprises the compounds (V.1), (V.2), (V.3) and (VI) not present in the first top product, and also optionally small amounts of the compounds of formula (I), a side stream is obtained which consists essentially of compound of formula (I), and a second bottom product is obtained which comprises the compounds of formula (I) which are not present in the top product and are not present in the side stream.

11. The process according to claim 10, where, in the compounds of formulae (I), (V.1), (V.2), (V.3) and (VI), R¹ is isobutyl.

12. The process according to claim 10, where the first top product and/or the second top product are used for the hydrogenation in step c).

13. The process according to claim 10, where the side stream and the second bottom product differ with regard to the fraction of stereoisomers of the compounds of formula (I).

14. The process according to claim 1, where the hydrogenation in step c) takes place in the presence of a hydrogenation catalyst which is selected from homogeneous and heterogeneous catalysts which comprise at least one metal component selected from metals, metal compounds or mixtures thereof.

15. The process according to claim 14, where the hydrogenation catalyst is palladium on carbon, platinum on carbon, Raney nickel or Raney cobalt.

16. The process according to claim 1, where, in step d), the hydrogenation product obtained in step c) is subjected to a distillative separation.

17. The process according to claim 1, where, in step d), a fraction comprising 2-substituted 4-methyltetrahydropyrans (II) is isolated from the hydrogenation product obtained in step c), where the diastereomer ratio of the cis-diastereomer to the trans-diastereomer is in a range from 60:

40 to 100;

0.

18. The process according to claim 1, where, in step d), a fraction comprising 2-substituted 4-methyltetrahydropyrans (II) is isolated from the hydrogenation product obtained in step c), said fraction having a content of dioxane compounds of formula (VI)

19. The process according to claim 18, where, in step d), a fraction comprising 2-isopropyl-4-methyltetrahydropyran (II) is isolated.

20. The process according to claim 18, wherein R¹ is butyl and said fraction having a content of dioxane compounds of formula (VI)

21. The process according to claim 14, wherein the metal compound is a metal oxide.