Organic compounds -- part of the class 532-570 series – Organic compounds – Heterocyclic carbon compounds containing a hetero ring...
Reexamination Certificate
2001-04-25
2002-09-10
Solola, T. A. (Department: 1626)
Organic compounds -- part of the class 532-570 series
Organic compounds
Heterocyclic carbon compounds containing a hetero ring...
C549S527000
Reexamination Certificate
active
06448418
ABSTRACT:
The invention relates to a process for the epoxidation of olefins in a two-phase reaction system with percarboxylic acids formed in situ.
Epoxides of olefinically unsaturated compounds represent an important class of intermediates. In a process known for a long time, olefins are epoxidized by reaction with percarboxylic acids, which can be produced in situ from hydrogen peroxide and carboxylic acids. By scission, the oxiran ring formed in place of the olefinic double bond can react with a large number of compounds containing active hydrogen, thereby opening up an extensive secondary chemistry.
In the processes of the state of the art, the reactivity of epoxides results in the formation of by-products. Thus epoxides react in the presence of water and carboxylic acids to give glycols or their mono- and diester, the scission of the oxiran ring being acid-catalyzed. The problem here is that the formation of the percarboxylic acid is also acid-catalyzed, so the process is often carried out in the presence of mineral acids as catalysts.
DE-B 1 230 005 discloses a process for the epoxidation of linear alpha-olefins which uses peracetic acid free of water and mineral acid as the epoxidizing reagent and is carried out in the presence of an inert solvent such as acetone, methyl acetate or ethyl acetate. The disadvantages are the long reaction times of several hours, the incomplete olefin conversion and the high proportion of by-products, especially glycol monoester. Also, the epoxidizing reagent used is expensive.
DE-C 195 19 887 describes a process for the epoxidation of olefinically unsaturated compounds with percarboxylic acid prepared in situ, said process being carried out with water as the only solvent and in the presence of inhibitors. No information is given on the exact composition of the product mixture.
DE-A 15 68 016 discloses a process in which alpha-olefins are epoxidized in a water-immiscible solvent with a percarboxylic acid formed in situ in the aqueous phase, the reaction mixture being stirred in such a way as to maintain a single phase interface. This procedure demands very long reaction times.
EP-A 0 032 989 describes a process for the epoxidation of alpha-olefins with performic acid formed in situ, said process being carried out in the absence of a solvent and an acid catalyst. Epoxidation by this process demands a long overall reaction time. Also, the olefin conversion is unsatisfactory despite the long reaction time.
It is an object of the present invention to provide a process for the epoxidation of olefins in which a quantitative conversion is achieved and products of high purity are obtained after short reaction times.
We have found that this object is achieved by a process for the epoxidation of olefins with percarboxylic acid in a reaction mixture consisting of an aqueous phase and an organic phase, the percarboxylic acid being formed in situ in the aqueous phase from hydrogen peroxide and a carboxylic acid or a carboxylic anhydride, and the olefins being dissolved in an organic solvent in the organic phase. The process according to the invention comprises carrying out the epoxidation in several steps, each step being carried out with a fresh aqueous phase and the aqueous phase being separated off after each step.
In terms of the present invention, olefins are compounds containing one or more olefinic double bonds. Examples of compounds with olefinic double bonds are linear or branched mono- and diolefins having from 6 to 30 C atoms, unsaturated, optionally hydroxy-substituted fatty acids having from 6 to 24 C atoms and from 1 to 5 double bonds, their esters or triglycerides, and unsaturated alcohols having from 6 to 24 C atoms and from 1 to 3 double bonds. Polyalkenes and terpenes are also olefins in terms of the present invention. In addition to the double bond(s), the olefins can contain other functional groups which do not react, or react only slowly, with the solvent or the epoxidizing reagent under the reaction conditions. For example, the olefins can contain heteroatoms, such as an ether oxygen, or can be substituted by hydroxyl groups, carboxylic acid groups, carboxamide, carboximide, carboxylic acid ester, lactam or lactone groups, aromatic radicals or halogen atoms. The olefin used may already contain epoxy groups, keto groups or cyclic carbonate groups.
Examples of suitable olefins are mono- or diolefins having from 6 to 30 C atoms, preferably from 10 to 24 C atoms and particularly preferably from 12 to 18 C atoms, which can be branched or unbranched. Branched olefins can also be branched on the double bonds. Both cis and trans isomers can be used. Examples are 1-hexene, 2-hexene, 3-hexene, 1,3-hexadiene, 1,4-hexadiene, 3-methyl-1,3-pentadiene, 2-methyl-1-pentene, 3,3-dimethyl-1-butene, 1-heptene, 3-heptene, 1-octene, 4-octene, 1-nonene, 1-decene, 1-undecene, 1-dodecene, 1-tetradecene, 1-hexadecene, 1-octadecene. The preferred olefins are linear, for example the linear olefins mentioned above, of which those with a terminal double bond (linear alpha-olefins) are particularly preferred. Of the linear alpha-olefins, those with an even number of C atoms are particularly preferred because of their ready availability from petrochemical processes.
Other suitable olefins are cyclic olefins such as cyclohexene, cyclooctene, cyclooctadiene, cyclodecene and cyclododecene, and their substituted derivatives, for example substituted cyclohexenes such as 1,3-dimethylcyclohexene, 1,4-dimethylcyclohexene or 1-ethylcyclohexene.
Other suitable olefins are terpenes, terpene alcohols and other natural substances with one or more double bonds, such as steroids. In addition to the olefinic double bonds, these can contain other functional groups such as hydroxyl or keto groups. Examples are 2-carene, delta-3-carene, alpha-pinene, beta-pinene, verbenol, myrtenol, cis-jasmone, dihydrocarveol, alpha-terpinene, gamma-terpinene, alpha-ionone, beta-ionone, limonene, carvone, citronellic acid, trans-vaccenic acid, geraniol, farnesol, phytol, citronellol, ergosterol, myrcene, squalene and camphene.
Other suitable olefins are unsaturated fatty acids having from 6 to 24 C atoms and from 1 to 5 double bonds, which can optionally be substituted by hydroxyl groups, for example oleic acid, elaidic acid, linoleic acid, linolenic acid, arachidonic acid, linolenelaidic acid, linoelaidic acid, myristoleic acid, palmitoleic acid, undecenoic acid or ricinoleic acid. Other suitable olefins are the esters of unsaturated fatty acids, especially their triglycerides such as those which occur in animal and vegetable fats and oils, for example in soya oil, sunflower oil, linseed oil, rapeseed oil, colza oil, groundnut oil, palm oil, coconut oil, castor oil, tallow, lard and fish oil. Other suitable olefins are unsaturated fatty alcohols having from 1 to 3 double bonds, such as oleyl alcohol, elaidyl alcohol, linoleyl alcohol, linolenyl alcohol and arachidonyl alcohol.
Other preferred olefins are polyalkylenes such as polyisobutene.
The olefins are dissolved in an organic solvent. Suitable organic solvents form a two-phase reaction system with the epoxidizing reagent consisting of a carboxylic acid and aqueous hydrogen peroxide solution, so they are water-immiscible organic solvents or organic solvents having only a limited miscibility with water. The organic solvents are used in an amount appropriate for the formation of an organic phase separated from the aqueous phase. Solvents which are completely miscible with water are therefore unsuitable.
Preferred organic solvents are also inert toward aqueous hydrogen peroxide solution, carboxylic acids and percarboxylic acids and especially toward the epoxides formed. Preferred solvents have a markedly different density from that of water, hydrogen peroxide solution or the aqueous carboxylic acid solution.
Preferred organic solvents have at least a limited miscibility with water. The water absorption capacity of the organic solvent at 25° C. is preferably at least 0.1 and at most 10 mol %, particularly preferably at least 0.1 and at most 5 mol %, very p
BASF - Aktiengesellschaft
Solola T. A.
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