Organic compounds -- part of the class 532-570 series – Organic compounds – Heterocyclic carbon compounds containing a hetero ring...
Patent
1997-08-05
1998-09-15
Owens, Amelia
Organic compounds -- part of the class 532-570 series
Organic compounds
Heterocyclic carbon compounds containing a hetero ring...
C07D30114
Patent
active
058081143
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an improved process for preparing epoxides, in particular alkylene oxides, from, corresponding starting compounds, in particular from the corresponding olefins, by means of aromatic peroxycarboxylic acids.
2. Description of the Background
The epoxidation of olefins with peroxycarboxylic acids, in particular with m-chloroperoxybenzoic acid, is a well established laboratory method for the synthesis of epoxides.
The method is extensively described in the chemical literature, for example by Y. Sawaki in S. Patai (ed.), Chem. Hydroxyl, Ether Peroxide Groups, p. 590-593 (1993) (1).
However, the method is less suitable for preparing epoxides on a larger scale, since the peroxycarboxylic acid is used in stoichiometric amounts and the resulting carboxylic acid has to be expensively regenerated by reaction with hydrogen peroxide.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a process for preparing alkylene oxides by epoxidation of olefins with aromatic peroxycarboxylic acids which permits a simple, safe and economical recycle of the resulting carboxylic acid into peroxycarboxylic acid without use of hydrogen peroxide.
We have found that this object is achieved by a process for preparing an epoxide from the corresponding olefin by means of an aromatic peroxycarboxylic acid, which comprises a step A of epoxidizing the olefin and removing the resulting aromatic carboxylic acid from the epoxide, a step B of catalytically hydrogenating the removed aromatic carboxylic acid to the corresponding aromatic aldehyde, and a step C of oxidizing this aldehyde with oxygen or an oxygen-containing gas mixture back to the aromatic peroxycarboxylic acid for re-use for preparing an epoxide.
DETAILED DESCRIPTION OF THE INVENTION
In principle, any olefin can be epoxidized in step A. Preference is given to olefins which carry not more than one electron-attracting substituent directly on the double bond. Particular preference is given to olefins without electron-attracting substituents on the double bond. Examples of useful olefins are linear or branched C.sub.2 -C.sub.40 -olefins, in particular C.sub.3 -C.sub.24 -olefins, or cyclic olefins, such as ethylene, propene, 1-butene, 2-butene, isobutene, 1-pentene, 2-pentene, 1-hexene, 1-heptene, 1-octene, 2,4,4-trimethyl-1-pentene, 2,4,4-trimethyl-2-pentene, 1-nonene, 1-decene, 1-dodecene, 1-tetradecene, 1-hexadecene, 1-octadecene, C.sub.20 -olefin, C.sub.22 -olefin, C.sub.24 -olefin, C.sub.28 -olefin or C.sub.30 -olefin, cyclopropene, cyclobutene, cyclopentene, cyclohexene, cyclooctene, vinyl alkyl ethers such as vinyl methyl ether, vinyl ethyl ether or vinyl butyl ether, allyl chloride, allyl alcohol, vinyl acetate, vinyl propionate, styrene and also compounds having a plurality of olefinic double bonds such as 1,3-butadiene, isoprene, cyclopentadiene or cyclooctadiene. It is also possible to use olefin mixtures.
The process of the present invention is particularly highly suitable for epoxidizing propene to propylene oxide.
Suitable aromatic peroxycarboxylic acids are in particular compounds of the general formula I ##STR1## where R.sup.1 to R.sup.3 are independently of one another hydrogen, C.sub.1 -C.sub.6 -alkyl, C.sub.3 -C.sub.8 -cycloalkyl, C.sub.6 -C.sub.14 -aryl, C.sub.7 -C.sub.12 -phenylalkyl, halogen, C.sub.1 -C.sub.6 -alkoxy, C.sub.3 -C.sub.8 -cycloalkoxy, C.sub.6 -C.sub.14 -aryloxy or C.sub.7 -C.sub.12 -phenylalkoxy and one of R.sup.1 to R.sup.3 can also be a further peroxycarboxyl group or a carboxyl group.
More particularly, the substituents R.sup.1 to R.sup.3 have independently the following meanings: ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl or n-hexyl, in particular methyl or tert-butyl; cyclohexyl, cycloheptyl or cyclooctyl, in particular cyclopentyl or cyclohexyl or substituted C.sub.3 -C.sub.8 -cycloalkyl, in particular 1-methylcyclopentyl or 1-methylcyclohexyl; 2-anthryl or 9-anthryl, in particular phenyl; 1-phen
REFERENCES:
patent: 4010195 (1977-03-01), Isogai et al.
Y. Sawaki, Wiley Interscience, pp. 590-595, 1993, "Supply. E2: The Chemistry of Hydroxyl, Ether and Peroxide Groups".
Fischer Rolf
Rieber Norbert
Schnurr Werner
Schulz Michael
Teles Joaquim Henrique
BASF - Aktiengesellschaft
Owens Amelia
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