Improved process for preparing epoxides from aldehydes or ketones

Abstract

The invention relates to an improved process for preparing epoxides from aldehydes or ketones by reacting a ketone or aldehyde with at least one sulfonium salt, and to sulfonium salts that may be used in the process of the invention.

Claims

1-13. (canceled)

14. A process for preparing epoxides, in which a ketone or aldehyde is reacted at least with a sulfonium salt of formula (I), ##STR00004## and/or a sulfonium salt of formula (II),
X.sub.2SY+Z.sup.−  (II), where in formula (I) and formula (II) X is methyl and Y is linear C.sub.2 to C.sub.11 alkyl, and where in formula (II) Z is chloride, bromide, iodide or carbonate, in the presence of a base.

15. The process according to claim 14, wherein in formula (I) and formula (II) X is ethyl, n-propyl, n-butyl, n-pentyl, n-heptyl, n-octyl, n-nonyl, n-decyl or n-undecyl.

16. The process according to claim 14, wherein said base is alkali metal hydroxide, more preferably sodium hydroxide or potassium hydroxide.

17. The process according to claim 14, wherein the ketone is the compound of formula (III), ##STR00005## and the epoxide is the compound of formula (IV), ##STR00006##

18. The process according to claim 14, wherein the sulfonium salt of formula (I) or (II) is used in the form of a melt or of a solution.

19. The process according to claim 14, wherein the reaction is effected without solvent or in the presence of at least one solvent.

20. The process according to claim 14, wherein at least one solvent is a dialkyl sulfide of formula (V),
X—S—Y   (V), where X and Y are as defined in formula (I).

21. The process according to claim 14, wherein the aldehyde or ketone is reacted in the presence of from 0.1 to 3 molar equivalents of dialkyl sulfide of formula (V) as solvent, based on the aldehyde or ketone.

22. The process according to claim 17, wherein the compound of formula (III) is reacted in the presence of from 1.1 to 1.5 molar equivalents of dialkyl sulfide of formula (V) as solvent, based on the compound of formula (III).

23. The process according to claim 14, wherein the aldehyde or ketone is reacted with from 1.0 to 2 molar equivalents of sulfonium salt of formula (I) or (II), based on the aldehyde or ketone.

24. The process according to claim 17, wherein the compound of formula (III) is reacted with from 1.0 to 1.3 molar equivalents of sulfonium salt of formula (I) or (II), based on the compound of formula (III).

25. The process according to claim 14, wherein the reaction is carried out at temperatures of from 20° C. to 100° C.

26. The process according to claim 14, wherein the reaction is carried out at temperatures of from 30° C. to 60° C.

27. The process according to claim 14, wherein the sulfonium salt of formula (I) is obtained by reacting a dialkyl sulfide of formula (V) with dimethyl sulfate.

28. The process according to claim 14, wherein the sulfonium salt of formula (II), in which X and Y are as defined in formula (II) and Z is chloride, bromide or iodide, is obtained by reacting a dialkyl sulfide of formula (V) with methyl chloride, methyl bromide or methyl iodide, depending on the radical Z.

29. The process according to claim 14, wherein the sulfonium salt of formula (II), in which X and Y are as defined in formula (I) and Z is carbonate, is obtained by reacting a dialkyl sulfide of formula (V) with dimethyl carbonate.

30. A sulfonium salt of formula (I) and of formula (II) according to claim 14.

Description

EXAMPLES

2-(4-Chlorophenyl)-2-(1-cyclopropylethyl)oxirane

a) Preparation of the sulfonium Salt butylmethylsulfonium methosulfate

[0037] A first reactor (A) was charged with 1800 g (16.93 mol) of n-butyl methyl sulfide and this was then heated to 40° C. To this was then metered in with stirring 1903 g (14.94 mol) of dimethyl sulfate and the temperature of the reaction mixture was increased to 100° C. over the course of 1 hour. The reaction mixture was left at 100° C. for 1 hour with stirring and then cooled to 40° C. over the course of 1 hour.

b) Epoxidation

[0038] A second reactor (B) was charged with 1300 g (12.23 mol) of n-butyl methyl sulfide. To the n-butyl methyl sulfide in the second reactor (B) was then added 26 g of water (1.43 mol) and 1412 g (21.39 mol) of potassium hydroxide and the temperature of the mixture in the second reactor (B) was increased to 40° C. The second reactor (B) was then inertized with nitrogen. To the mixture in the second reactor (B) was then added 3000 g (content: 92.2% by weight, 13.23 mol) of 1-(4-chlorophenyl)-2-cyclopropylpropan-1-one [compound of formula (III)]. The contents of the first reactor (A), which contains the sulfonium salt in the form of a melt, were metered into the mixture in the second reactor (B) at 40° C. over the course of 120 minutes while stirring vigorously. The first reactor (A) was rinsed with 500 g of n-butyl methyl sulfide. The rinse solution from the first reactor (A) was then metered into the second reactor (B), likewise at 40° C., with vigorous stirring. The reaction mixture was then stirred at 40° C. for two hours. Once the reaction had ended, the reaction mixture was hydrolyzed. This was done by charging a third reactor (C) with 4000 g of water having a temperature of 25° C. and adding the reaction mixture from the second reactor (B) to the third reactor (C) while stirring. The pH of the reaction mixture was then at 25° C. adjusted to pH 6-7 with 1060 g (8.72 mol) of 30% hydrochloric acid while stirring vigorously. The mixture was then left to stand to allow phase separation, resulting in a two-phase mixture formed from an upper organic phase and a lower aqueous phase. The lower aqueous phase was run off and the upper organic phase then washed with 4000 g of water. A low-boiling fraction was then first distilled off from the washed organic phase by distillation at 10 hPa up to a bottoms temperature of not more than 91° C. 3774 g of n-butyl methyl sulfide (content: at least 90% by weight) was then distilled off at 91° C. and 10 hPa, leaving behind in the bottoms 3157 g of 2-(4-chlorophenyl)-2-(1-cyclopropylethyl)oxirane [compound of formula (IV)] (content: 90% by weight, yield: 96.6% of theory). The recovered n-butyl methyl sulfide can be reused in a subsequent reaction for the preparation of 2-(4-chlorophenyI)-2-(1-cyclopropylethyl)oxirane.