DE2752920A1 - PROCESS FOR THE MANUFACTURING OF EPOXIDS - Google Patents

Description

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Process for the production of epoxides

A k ζ ο GmbH
Wuppertal

The present invention relates to a process for the preparation of epoxides (oxiranes) by reacting compounds which contain one or more olefinic double bonds with peracetic acid. The epoxidation with peracids has hitherto been carried out in such a way that the percompound was first prepared, which was by distillation
Free of reducing and decomposing substances, such as aldehydes and traces of heavy metals, isolated and finally reacted with the olefinic compound (cf.
Ullmann's Encyclopedia of Industrial Chemistry, 4th Edition, Volume 10, page 563 ff, Verlag Chemie, Weinheim / Bergstr.
1975). This method is disadvantageous in that
Extraction of the peracid is associated with the risk of an explosion. The purification of peracetic acid, which is produced by the oxidation of acetaldehyde with oxygen, cannot be dispensed with because
the unreacted acetaldehyde is reacted with the peracetic acid in a redox reaction to form acetic acid.

A process has now been found in which the dangerous purification of peracetic acid by distillation is unnecessary.

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The present invention is a method for producing a epoxides of an olefin nit a boiling point above 40 ⁰ C at 1 to 15 bar by the oxidation of acetaldehyde by means of oxygen or an oxygen containing gas to the peracetic acid in an organic solvent and in the presence of a Echwermetall-oxidation catalyst and anschlieCender epoxidation of the olefin by means of peracetic acid at temperatures from 50 to 150 ⁰ C, if appropriate under a pressure bar up to 15 °. The process is characterized in that the acetaldehyde-, solvent- and catalyst-containing peracetic acid reaction mixture obtained in the oxidation of the acetaldehyde is reacted with an olefin or the solution of an olefin in an organic solvent in the presence of a complexing agent and optionally an epoxidation agent and while this is being passed through an inert gas, unreacted acetaldehyde, solvent and some acetic acid are distilled off.

According to a preferred Uhrungeform f of the method the peracetic acid reaction mixture is cooled to -10 to +10 ⁰ C, the Komplexlerungsmittel and ge optionally the Epoxydationskatalysator the peracetic acid reaction mixture or the olefin or olefin solution are added and the peracetic acid reaction mixture gradually metered into the olefin or the olefin solution kept at epoxidation conditions.

According to a further preferred embodiment of the process according to the invention, the olefin or the olefin solution and at the same time the pereselgic acid reaction mixture are continuously metered into a reactor maintained at epoxidation conditions, while an inert gas is passed through

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unreacted acetaldehyde, solvent and, in some cases, acetic acid are distilled off and the liquid epoxide-containing reaction mixture is continuously drawn off from the reactor sump.

The first stage of the process, i. H. the oxidation of acetaldehyde with oxygen or oxygen-containing gases, such as air, to peracetic acid is carried out according to known processes in which the acetaldehyde diluted with a solvent is reacted with oxygen or air. In this regard, D. Swern, Chemical Reviews, Vol. 45 (1949), pages 5-8. In the art, the reaction takes place in the presence of a catalyst preferred. For this, reference is made to DT-AS 11 65, for example.

Examples of suitable catalysts are FeCl ₃ , Fe (NO ₃ ), Co (NO ₃ ), Co (CH ₃ COO) ₂ and molybdenum acetonylacetonate. The iron and cobalt salts practically do not differ with regard to conversion and selectivity, the selectivity with regard to peracetic acid formation is over 90%, the aldehyde conversion is approx. 60%.

The catalyst is used in customary amounts, for example in amounts from 0.001 to 0.01 percent by weight, based on on acetaldehyde.

The oxidation is carried out at the temperatures customary here, for example at 0 to 30 ^° C., preferably between 0 and 20 ^° C. The reaction times are usually 30 to 120 minutes.

Acetone, Easigeeter, chlorobenzene, methyl ethyl ketone and acetic acid are used as solvents for the oxidation of acetaldehyde or methylene chloride, preferably acetone or ethyl acetate, are used.

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The amount of solvent is chosen so that the concentration of acetaldehyde in the oxidation mixture is in the range of 5 to 40%, preferably in the range from 10 to 20%.

It is essential to the invention that the oxidation of the Acetaldehyde obtained reaction mixture is not worked up in order to separate off pure peracetic acid, but the olefin is reacted with the reaction mixture containing acetaldehyde, solvent and catalyst. Meanwhile, will be continuous most of the organic solvent and partly the acetic acid formed and the unreacted Acetaldehyde is distilled off with the addition of inert gas. This is of course only possible if the boiling points the inert organic solvents and acetaldehyde are lower under the conditions of epoxidation used as the boiling point ds3 for the epoxidation Olefins. Accordingly, the process according to the invention is only suitable for the conversion of those olefins whose boiling point is is higher than the boiling point of acetaldehyde under the epoxidation conditions to be considered here. The selection of a suitable inert organic solvent depends of course on the boiling point of the one to be epoxidized Olefins, d. H. the boiling point of the organic solvent must be lower than under the conditions of the epoxidation the boiling point of the olefin ..

Olefins which can be epoxidized by the process according to the invention are normal-alkenes, iso-alkenes, substituted alkenes, oils, unsaturated fatty acids and polyolefins with intermediate and / or terminal double compounds. The following are examples of such alkenes:

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Hexene-1, octene-1, decene-1, undecene-1, dodecene-1, octadecene-1, Polycyclopentadiene, polybutadiene-1,2 and / or polybutadiene-1.4, Allyl chloride / propylene trimer, linseed oil and oleic acid. All these Olefins have boiling points which are higher than the boiling point of acetaldehyde. Examples of olefins which are not implemented by the process according to the invention can, because their boiling point is lower than the boiling point of acetaldehyde, are Athens, propene and butenes.

The epoxidation is carried out at temperatures ranging from 5O to 150 ⁰ C, preferably at 80 to 110 ⁰ C and at pressures in the range up to 15 bar. The epoxidation is carried out under pressure when a comparatively low-boiling solvent is used, which is necessary when the olefinic compound to be epoxidized also has a comparatively low boiling point.

Suitable solvents are, for example, acetone, ethyl acetate, methylene chloride, methyl chloride, chlorobenzene and methyl ethyl ketone. For economic and procedural reasons, the same solvent is used in epoxidation as in the oxidation of acetaldehyde, preferably acetone or ethyl acetate.

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In the following table some of the possible and useful process parameters are summarized as an example:

Alkene temperature pressure solvent <° c> (bar) Witches-1 90-100 12th Methylene chloride Octene-1 90-100 3 acetone Decene-1 90-100 1 Ethyl acetate Polybutadiene-1.2 90-100 1 m Polybutadiene-1.4 90-100 1 H Octadecene-1 90-100 1 N Undecene-1 90-1OO 1 M. Propylene triraer 90-100 1 ■ oleic acid 90-100 1 ■ linseed oil 90-100 1 N Allyl chloride 90-100 15th Methylene chloride

Both for complexing from the oxidation of the aldehyde heavy metal catalysts contained in peracid as well as to prevent peracid decomposition through wall reaction With metallic materials (see M. Andoh et.al. Nippon Kagaku Kai Shi (1975), No. 8, 1383), a complexing agent is used in the epoxidation stage. Suitable Complexing agents are e.g. polyphosphoric acid, pyromellitic acid and pyridinecarboxylic acids.

If desired, one of the usual epoxidation methods can be used Epoxidation catalysts are used. These include, for example, sulfuric acid, tr! Fluoroacetic acids, tungsten '

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and molybdenum acid, alkanesulfonic acids, cation exchange resins and zinc phosphate. The compounds polyphosphoric acid and pyromellitic acid which are effective as complexing agents also have a catalytic influence on the epoxidation.

The epoxidation catalysts or complexing agents are in amounts of 0.01 to 1 percent by weight, preferably in amounts of 0.1 to 0.3 percent by weight, based on the Peracid, used.

Polyphosphoric acid or polyphosphoric acid are preferably used as complexing agents and epoxidation catalysts in the epoxidation Pyromellitic acid or sulfuric acid as an epoxidation catalyst and a pyridine carboxylic acid as a complexing agent used.

In contrast to the known process, the catalyst used in the oxidation of the acetaldehyde remains in the Epoxidation reaction mixture. It affects in crucial Measure the course of the epoxidation. It has been shown that the selectivity in the epoxidation by some of the the oxidation of acetaldehyde used catalysts is adversely affected, this is for example with the iron-containing inorganic catalysts are the case. This can be explained as follows. It is known that a cyclic addition complex is formed as an intermediate in epoxidation (see Bar tie tt. Rec. Chem. Proc, U, 51 (1960);

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I ♦ ι

C H ...

Ο-Ον

C-R

'C-R

This addition complex can, as our investigations showed, decompose in two directions to give different reaction products:

: C - R

a.

HO

C-R

HO

j ♦ O + .CR C O '

Heg a. indicates the normal decomposition to epoxy, way b. is strongly catalyzed e.g. by heavy metal ions, i.e. the decrease in selectivity is based only to a small extent on the direct decomposition of the peracid, since in the absence of olefinic double bonds the peracid is due to its presence of heavy metal ions under the same reaction conditions

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disintegrates much more slowly. It is therefore necessary Metals, which are present in the form of inorganic salts during the oxidation of the acetaldehyde, by precipitation or to render complex formation harmless. The compounds mentioned above are suitable for this purpose.

Compared to the known method, the invention has Process has the advantage that the most explosive distillation of peracetic acid and the associated distillation Process steps are omitted. In addition, the concentration of peracetic acid in the process according to the invention Epoxidation reaction mixture can always be kept low, with a rapid reaction with the olefinic Connection takes place. Since the unreacted acetaldehyde is largely distilled off in the process according to the invention, occurs practically no reaction of the same with the peracetic acid. This and the simultaneous distillation of the for The solvent required for the oxidation but disadvantageous for the epoxidation is a very high selectivity achieved on epoxy compounds.

example 1

200 g of acetaldehyde and 1800 g of ethyl acetate were placed in an enamelled steel reactor equipped with a cooling jacket, a gas inlet and a gas discharge pipe and a magnetic stirrer, and 0.01% by weight of FeCl ₃ - based on acetaldehyde - ale catalyst were added. In the ^{cooled to +10 0} C mixture were two hours under

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a pressure of about 4 bar 1 normal liter / h of oxygen.

The analysis of the reaction mixture showed an aldehyde conversion of 6 3% and a peracetic acid selectivity of 97%. The reaction mixture was used without further work-up in the epoxidation described below.

For the epoxidation of decene-1, 100 g of decene-1 were placed in a tubular reactor (bubble column) and ^{heated to 100 °} C. by means of jacket heating. Thereafter, at a flow rate of 20 liters per hour of nitrogen through the decene-1 were durchgeleitet.Anschließend 2 85 g of prepared in the manner described above peracetic acid Raaktionsgemisches to 0 ⁰ C cooled, treated with 0.1 g of polyphosphoric acid and within 15 minutes promoted into the heated reactor. The reaction was continued for a further 5 minutes while constantly bubbling through nitrogen. The majority of the low boilers distilled off and was condensed in a condenser. In addition to ethyl acetate, acetic acid and acetaldehyde, the distillate also contained 29% of the peracetic acid used.

A peracetic acid-free epoxidecane solution was produced from the bottom of the reactor removed and the solvent was distilled off. The conversion, based on decene-1, was 33% based on peracetic acid 71%. The selectivity was 98% based on epoxydecane and 92% based on peracetic acid.

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Example 2

For kontinuferlichen production of epoxy octadecane a tubular reactor was used, which in its inner part with a steam heated, wound tube coil having an inlet tube and a gas outlet tube at the upper end and a gas inlet tube at the bottom of UNR ¹ in its outer part by a spiral, a gas inlet tube at the lower end and a gas discharge pipe at the upper end, the lower discharge pipe of the inner pipe coil opening into the lower part and the upper gas discharge pipe of the inner pipe coil opening into the upper part of the outer reactor part.

^{1540 g of a liquid reaction mixture cooled to 0} ° C., which consisted of 765 g of 1-octadecene and a peracetic acid-containing reaction mixture as described in Example 1 and mixed with polyphosphoric acid, were metered into the upper feed line of the inner pipe coil every hour. The reaction mixture containing peracetic acid consisted of 115 g of peracetic acid, 40.4 g of acetaldehyde, 2.8 g of acetic acid, 980 g of ethyl acetate, 0.1 g of FeCl and 0.35 g of polyphosphoric acid.

The reaction mixture ran from top to bottom through the steam-heated coiled pipe coil. Ee filled their volume about 20% off. A stream of inert gas was introduced at the lower end of the pipe coil and directed towards the reaction gas. Most of the low boilers evaporate (Ethyl acetate, acetic acid, acetaldehyde and unreacted peracetic acid) and passed through the upper gas inlet pipe in the upper space of the outer reactor part, which as The vapor space of the post-reaction zone functions. The peracetic acid-free epoxy-decane solution passes through the lower

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Discharge pipe of the coil into the lower part of the outer reactor part, which is used as a post-reaction space acts. Inert gas was also fed into this part of the reactor. The remaining part of the low boilers evaporated there and the low boiler evaporated in the pipe coil was transferred to the upper part of the outer reactor part withdrawn a cooler and fed to a condenser. The epoxy-decane solution was taken from the post-reaction room drawn off and then worked up by distillation.

The conversion, based on octadecene-1, was 42%, based on on peracetic acid 92%. The selectivity, based on epoxy-octadecane, was 97%, based on peracid 90%.

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Claims (6)

A3GW318O4 claims: 1. A process for the production of an epoxide from an olefin with a boiling point above 10 C at 1 to 15 via oxidation of acetaldehyde by means of oxygen or oxygen-containing gases to peracetic acid in an organic solvent and in the presence of a Schv / erruitall oxidation catalyst and subsequent epoxidation of the olefin bin by means of peracetic acid hui temperatures of 50 to 150 C, optionally under a pressure bar to 15, characterized in that the Bel ir.an dDr oxidation of acetaldehyde r.nfallende acetaldehyde, solvent and katalysatorh-protean Poressigsüure-Heaktionsgemisch with an »olefin cdsr of reading« »inas olsfins in an organic solvent ir. Epoxidationtrkatalysators unsetii: and during .lcr. ζ cn while passing a Inertgase3 unv.n "geset = tc? n A :: ota? .dohyd, Löcungsmittel UNJ distilled partly acetic acid. 2. The method of claim 1, characterized gskennzeichr.ot that cools rcn the peracetic acid Reaktionsgaraisch to -10 to +10 ⁰ C, the Komplexierungsaiittel gegebnr.'nfalls and the oxidation catalyst He ngcmisch tion by the ec3ignüure-Roa ;: or the olefin or the olefin solution is added and the acetic acid reaction mixture is gradually metered into the olefin or the olefin solution, which is maintained at epoxidation conditions. L J 909822/0270 BATH ORIGINAL Γ Π A3GW318O4 3. The method according to claim 1, characterized in that one the olefin or the olefin solution and at the same time the peracetic acid reaction mixture continuously metered into a reactor maintained at epoxidation conditions and continuously withdraws the liquid epoxy-containing reaction mixture from the reactor sump. 4. The method according to claims 1 to 3, characterized in that that in the oxidation of acetaldehyde and the epoxidation acetone or vinegar aster as solvents used. 5. Process according to claims 1 to 4, characterized in that in the epoxidation al3 complexing agents and epoxidation catalyst polyphosphoric acid or pyromellitic acid is used. 6. Ancestors according to Claims 1 to 4, characterized in that the catalyst used in the epoxidation is sulfuric acid and a pyridinecarboxylic acid is used as a complexing agent. 909822/0270