DE2734240A1 - PROCESS FOR THE MANUFACTURING OF VINYLOXIRAN - Google Patents

Description

Bayer Aktiengesellschaft 2734240

Central Patents Department. Trademarks and licenses

509 Leverkusen. Bayerwerk Dz-by JG. JULY

Process for the production of vinyloxirane

The present invention relates to an improved process for the continuous production of vinyloxirane.

Vinyloxirane, the monoepoxide of butadiene, is an important technical intermediate that, due to its bifunctional Character is widely used in the field of polymers (F.C. Frostick, B. Phillips and P.S. Starcher, Journal of Am. Chem. Society, Vol 81, p. 3351 (1959)). Vinyloxirane belongs to the compound class of epoxy-vinyl monomers, which are characterized in that they can be converted into polyether by reaction of the epoxy ring. These then contain polyethers free vinyl groups suitable for crosslinking or copolymerization with other olefinic compounds. It is but also possible to polymerize vinyloxirane first on the olefinic double bond of the molecule, so that then Polymers are obtained which can be used for further reaction epoxy groups in the hydrocarbon chain exhibit.

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In accordance with the potential technical importance of vinyl oxirane, there have been no attempts in the past there was no need to find simple and economical processes for the production of vinyloxirane. This is so far, however, has not succeeded. The difficulties in the production of vinyloxirane consist on the one hand in the Reaction control of the reaction of butadiene with the epoxidation reagent, on the other hand in the separation of the Implementation of resulting, vinyloxirane-containing reaction mixtures.

For example, Pummerer and Reindel (Chem. Reports ([6, 335-339 (1933)) suggested the use of perbenzoic acid for the production of vinyloxirane from butadiene as early as 1933. However, the yields achieved were only 40-60%.

The production of vinyloxirane using an ethereal solution of this percarboxylic acid containing 3% peracetic acid is also unsatisfactory, since the yield is only 50 % (Pudovik, Ivanow, Journal of Gen. Chem. Of USSR Vol. 26, 3087 (1956) in English . translation).

Substantial improvements could also not be achieved by FC Frostick et.al., (Journal of Am.Chem.Soc. 81, 3354 (1959)). When butadiene was reacted with peracetic acid obtained by oxidation of acetaldehyde in organic solvents, a yield of only 56% was achieved.

Peracetic acid obtained by oxidation of acetaldehyde is also described in Japanese Patent Publication No. J 7-4046-284 as a reagent suitable for the preparation of vinyloxirane. It however, no yields are given.

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Process for making vinyloxirane using peracetic acid made from acetaldehyde to epoxidize butadiene, have the fundamental disadvantage that they are used as an adjuvant Acetaldehyde need, and that this adjuvant the process does not leave unchanged, so that a return to the process is practically impossible. In addition, such procedures are Complex in terms of technical implementation, since an additional oxidation stage is required. Besides, there is oxidation from acetaldehyde or other aldehydes to peracetic acid or percarboxylic acids a difficult reaction to carry out, their safety risks in the technical application, caused by the highly explosive ones occurring as intermediate stages Aldehyde peracrylates, are not insignificant (D.Swern, "Organic Peroxides", VoI 1, pp. 353, 354; Wiley-Interscience (1971)).

British Patent 735,974 (Union Carbide Corp.) proposes the epoxidation of butadiene to vinyloxirane Acetaldehyde or propionaldehyde monoperacylate, also obtained by oxidation of the corresponding aldehydes, can be used.

The conversion of acetaldehyde monoperacetate in the reaction with butadiene is only 33%. The ones used for the production of vinyloxirane itself subsequent work-up of such a reaction mixture by distillation takes place in the presence of the per compound, which excludes a technical application because of the existing risk of explosion.

Also the use of special procedural measures, such as those in German patent specification 1 216 306 for implementation Suggested by epoxidations bring in case

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of butadiene does not achieve the desired result, as in Example 3 this patent can be found where the epoxidation of butadiene by this process with peracetic acid only provides a 68% selectivity for vinyloxirane.

In US Pat. No. 3,053,856, the implementation of Acetonitrile and hydrogen peroxide described in the presence of butadiene, according to Example XII of this patent vinyloxirane emerges as the main product. However, in this process the carboxamide corresponding to the nitrile used in each case is obtained, which is to be regarded as a coproduct and either put to a suitable use or by dehydration In the nitrile must be converted back, is a technically satisfactory solution to the problem of vinyloxirane production not given.

The use of alkyl hydroperoxides, such as cumene and tert-butyl hydroperoxide, for the epoxidation of dienes under the catalytic influence of molybdenum or vanadium compounds is of Sheng and Zajacek (Journal of Organic Chemistry VoI 35, 6, 1839-1843 (1970)). Butadiene can be made according to this procedure be converted into vinyloxirane with 85-56 selectivity. In this reaction, as can be seen from equation (1), the alkyl hydroperoxide R-OOH is converted into the corresponding alcohol R-OH

R-OOH + CH ₂ = CH-CH = CH ₂ > CHp - CH-CH-CH ₂ + R-OH (1)

^ O

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converted. The hydrocarbon peroxide R-OOH thus acts as a Oxygen transmitter, so that after the release of the peroxide oxygen the corresponding alcohol is obtained as a by-product and often has to be removed as an undesirable by-product. The technical The possible uses of such a process are accordingly limited, since the alcohol by-product is not used in every case can be.

Another process, described in Belgian patent 747 316, is used to produce vinyloxirane carried out the reaction from butadiene and hydrogen peroxide in the presence of a tin-containing catalyst system. Next to the disadvantage that a solvent, such as n-propanol, is required to carry out the reaction, which itself can react with already formed vinyloxirane, high losses of product are to be expected, which are caused by this are that the water formed from the hydrogen peroxide used after the reaction with the butadiene with vinyloxirane reacts with cleavage of the epoxy ring. Furthermore, the catalyst is not separated off from the reaction mixture A task that is easy to solve on a technical scale.

As numerous as the suggestions that have been made for improvements to achieve the reaction in the epoxidation of butadiene to vinyloxirane, the efforts have been those for coping with the reaction mixtures containing the separation of vinyloxirane in an industrial implementation Problems that arise have been undertaken. These problems when working up mixtures containing vinyloxirane are essentially given by the fact that the epoxy ring in the molecule of vinyloxirane very easily enters into side reactions, which

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leads to sometimes considerable losses of vinyloxirane, and so the economic viability of an industrial process for production of vinyloxirane is no longer given. The risk of product loss occurs particularly when the Mixtures from which vinyloxirane is to be separated contain acidic components.

This is always the case when vinyloxirane is produced from butadiene and a percarboxylic acid, since then that of the percarboxylic acid corresponding carboxylic acid is inevitably contained in the reaction mixture.

In British patent specification 852 097 such Proposed reaction mixture for the separation of vinyloxirane and the carboxylic acid, the carboxylic acid, for example acetic acid, to remove by first a solution of vinyloxirane and the carboxylic acid in an organic, not in water soluble solvents such as chlorinated hydrocarbons, produces and then the solution with water or an aqueous solution of an inert alkali metal salt Extracted temperatures below 15 ° C. This extraction process is expensive because it not only requires an additional solvent, but also a subsequent separation of the water of the carboxylic acid necessary if the carboxylic acid is to be recovered. The extraction of carboxylic acids from aqueous solutions by distillation is, because of the formation of azeotropic mixtures, one that can only be mastered with considerable effort Task.

The scope of recovery for such an extraction process of vinyloxirane technically necessary measures is the

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See U.S. Patent 3,019,234. The resulting after addition of the largely insoluble solvent in water, Vinyloxirane and the solution containing the carboxylic acid must be extracted below 25 ° C. with water or an aqueous solution will. The extraction effort is considerable. From Example 1 of the above-mentioned patent it is apparent that 10 theoretical Extraction stages are required. In addition, work must be carried out at 0 C. The result of this process for the production of vinyloxirane given problem solution for loss-free separation of vinyloxirane and carboxylic acid is not satisfactory since there are not insignificant amounts of vinyloxirane in the aqueous phase after extraction.

In the French patent specification 1 468 814 it is proposed that the resulting after carrying out the epoxidation of butanediene, free carboxylic acid - in this case acetic acid - containing reaction mixture, which also contains an acetic acid ester as a solvent, Contains vinyloxirane and butadiene, with strong bases, such as alkali or alkaline earth hydroxides, to treat to free To neutralize carboxylic acid, which is thus withdrawn from the reaction with vinyloxirane. After the neutralization step, the separated aqueous, acetate-containing phase. The method according to the above patent specification produces a salt-containing one in each case Wastewater, even if the acetate-containing aqueous solution obtained after neutralizing the acetic acid Adding a strong acid would work up to recover the free acetic acid.

It can thus be seen from the previously known literature on processes for the preparation of vinyloxirane that all these processes only reveal approaches for an economical, technical production of vinyloxirane, but by no means

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a satisfactory cope with the technical requirements and the question of economic viability able to offer.

In contrast, it has now surprisingly been found that it is technically simple and economically advantageous Vinyloxirane can be made from hydrogen peroxide and butadiene, if you can

a) a 10 to 45 wt .-% of a water-soluble, acidic catalyst and aqueous containing 20 to 50% by weight of hydrogen peroxide Solution with a carboxylic acid containing 2 to 5 carbon atoms in the molar ratio of hydrogen peroxide to carboxylic acid

how 0.5 - 30: 1 ^{converts at temperatures from 10 to 70 0} C,

b) the reaction mixture obtained is extracted with an inert, organic solvent in countercurrent,

c) the essentially hydrogen peroxide and acidic catalyst containing aqueous raffinate of the extraction wholly or partially concentrated by distillative removal of water ,

d) the concentrated raffinate, and possibly not concentrated portion of the raffinate, restoring the amount required for the reaction with the carboxylic acid Concentrations of hydrogen peroxide and water-soluble acidic catalyst in the reaction stage (a) recycled, this to restore the hydrogen peroxide concentration required for the reaction with the carboxylic acid required hydrogen peroxide the portion of the raffinate to be concentrated before or after

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distillative removal of water according to (c) is added or to the possibly not concentrated part of the Raffinate is added,

e) containing essentially percarboxylic acid and carboxylic acid organic extract treated with water or an aqueous solution and

f) the now practically hydrogen peroxide-free, water-containing, organic extract subjected to an azeotropic distillation in such a way that the residual content of water in the bottom product of the azeotrope column is less than 0.5% by weight,

g) the organic solution now obtained, containing percarboxylic acid and carboxylic acid, with excess butadiene at a molar ratio of butadiene to percarboxylic acid of 1.5 to 6: 1 at temperatures from 0 ^° C. to 80 ^° C. and at a pressure of 0.8 converts up to 20 bar, and

h) the vinyloxirane-containing reaction mixture on distillative '.ve ^ e worked up, with pure vinyloxirane being isolated and the excess butadiene, the carboxylic acid and the inert organic solvent recovered in whole or in part be returned to the proceedings.

Percarboxylic acids suitable for the process according to the invention are those derived from aliphatic carboxylic acids with 2 to 5 carbon atoms, such as acetic acid, propionic acid, n-butyric acid, Isobutyric acid and valeric acid or trimethyl acetic acid and dimethyl propionic acid. Peracetic acid are particularly suitable, Perpropionic acid and perisobutyric acid. Perpropionic acid is particularly suitable.

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In the reaction according to (a) between hydrogen peroxide and the carboxylic acid in the presence of an acidic catalyst is formed an equilibrium between the carboxylic acid and the percarboxylic acid, which are represented according to the following equation can:

RC-OH + H ₀ O-RCO-OH + HO

Il ^ * Il * ·

The carboxylic acid depends on the concentration of acidic catalyst, e.g. sulfuric acid, and hydrogen peroxide the molar ratio of hydrogen peroxide to carboxylic acid to about 30 to 70% to percarboxylic acid.

In general, in addition to the 10 to 45% by weight of water-soluble, acidic catalyst, e.g., sulfuric acid or methanesulfonic acid, and containing 20 to 50% by weight hydrogen peroxide aqueous solution, the carboxylic acid in pure, undiluted form. But you can also use a water-containing or a hydrogen peroxide-containing one or use an acidic catalyst containing carboxylic acid, in which case the concentration of the aqueous Solution must change accordingly in order to achieve the ratio of hydrogen peroxide, acidic catalyst, Adhere to carboxylic acid and water. For example, instead of pure carboxylic acid, a mixture can also be used of carboxylic acid and hydrogen peroxide, for example a carboxylic acid containing 20% by weight of hydrogen peroxide. Of course must then correspond to the content of hydrogen peroxide in the carboxylic acid, the content of hydrogen peroxide in the

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aqueous, acidic catalyst and containing hydrogen peroxide Feed solution are adjusted so that the hydrogen peroxide contained in the carboxylic acid and that of the aqueous Solution results in a total use of hydrogen peroxide that corresponds to a content of 20 to 50 wt .-% hydrogen peroxide in the aqueous solution. For example, in such a Case where the carboxylic acid to be converted to percarboxylic acid already contains hydrogen peroxide, in the aqueous solution itself the Hydrogen peroxide content can be less than 20% by weight, e.g. 12 to 19% by weight. Within the specified concentration ratios of catalyst and hydrogen peroxide you can use all conceivable mixing ratios.

Preference is given to using a 20 to 43% by weight, particularly preferably 23 to 38% by weight acid catalyst and 22 to 35% by weight hydrogen peroxide containing aqueous solution.

Sulfuric acid is advantageously used as the water-soluble acid catalyst. Other water-soluble acids can also be used, for example sulfonic acids such as methane, xthane, propane, butane, isobutane sulfonic acid, benzenesulfonic acid, toluenesulfonic acid, trifluoromethane, 1-fluoroethane, perfluoroethane, perfluoropropane or perfluorobutanesulfonic acid; Phosphoric acid, phosphonic acids such as methane or ethane phosphonic acid, phosphinic acids, or acid salts such as sodium hydrogen sulfate or potassium hydrogen sulfate. Mixtures of water-soluble acids can also be used. Commercially available hydrogen peroxide, for example 30 to 90% by weight H ₂ O-, is used as the hydrogen peroxide for preparing the aqueous solution. Of course, hydrogen peroxide, which is obtained as a by-product of other chemical processes or as a recycle stream, is also suitable.

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The reaction temperature is generally around 10 to 70 C. It is expedient to work at 20 ° -60 ° C. Particularly beneficial are temperatures below 43 C / e.g. temperatures of 25 - 43 ° C for the conversion.

In general, the reaction is carried out until equilibrium has been established between the carboxylic acid and the percarboxylic acid. It however, it is also possible to terminate the reaction before equilibrium is reached and the reaction mixture thus obtained is the next process step, i.e. the extraction with the inert organic solvents.

For the reaction of the carboxylic acid with hydrogen peroxide, the pressure is not important, so that at normal pressure, increased Pressures or can be carried out at reduced pressure. In general, it is advantageous at pressures below 1.1 bar to be implemented, e.g. at pressures of 0.8 - 1.1 bar.

The reaction can be carried out in a wide variety of reaction vessels will. It is useful for a stationary concentration profile Care must be taken and in particular so-called dead zones in which parts of the reaction mixture are disproportionate linger long to avoid. For example, the usual reaction tubes of different diameters and sizes are suitable of different lengths, which can also be arranged as a closed circuit, e.g. as loop reactors, as well as Agitator vessel.

The reaction mixture from reaction stage (a) is now subjected to countercurrent extraction with the inert organic solvent according to (b) supplied. This countercurrent extraction can be carried out in one or more extraction units.

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Suitable solvents for the percarboxylic acids are all those which are inert with respect to the reaction mixture of reaction (a), with water immiscible, organic solvents. For example, aromatic hydrocarbons have been found to be suitable, which contain 6 to 10 carbon atoms, aliphatic or cycloaliphatic hydrocarbons each containing up to 12 carbon atoms, chlorinated hydrocarbons, which contain 1 to 10 carbon atoms and 1 to 4 chlorine atoms, and esters of 1 to 5 carbon atoms containing carboxylic acids with straight-chain or branched alcohols in which 1 to 8 carbon atoms are present in the molecule, as well as Xther, which contain 2 to 10 carbon atoms. Examples of suitable solvents are: benzene, toluene, xylene, n-pentane, isooctane, cyclohexane, methylene chloride, chloroform, 1,2-dichloroethane, 1,2-dichloropropane, methyl acetate, ethyl acetate, n-propyl acetate, isopropyl acetate, n-butyl acetate, isoamyl acetate, Methyl propionate, ethyl propionate, propyl propionate and butyl propionate, as well as chlorobenzene and Xther. But it is It is also possible to use mixtures of the solvents mentioned as solvents for the percarboxylic acid, in which case the components of the mixture are then advantageously chosen so that they have a similar boiling point. Chlorinated hydrocarbons are preferred, such as methylene chloride, dichloroethane or dichloropropane, aromatic hydrocarbons such as benzene, or Xther, such as diisopropyl ether or mixtures of these solvents are used. Benzene is very particularly preferably used as the solvent for the process according to the invention.

The quantitative ratio of organic solvent to the reaction mixture containing the percarboxylic acid to be extracted

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generally 10 to 0.1: 1. However, larger amounts of inert organic solvent can also be used. The most favorable range of the ratio of according to

(A) the reaction mixture obtained for the extraction according to

(b) The organic solvents to be used depend on the particular percarboxylic acid selected and the extraction properties of the organic solvent and can be determined in a simple manner by the person skilled in the art. For example, for the perpropionic acid / benzene system, it is advantageous to choose a ratio of the reaction mixture to be extracted / obtained in step (a) to benzene of 4 to 0.3: 1. If the extraction according to (b) is carried out in several extraction units, the amount of the organic solvent can vary from unit to unit within the specified limits.

The percarboxylic acid content in the extract can be determined by the amount of extractant and the number of extraction stages in can be varied within wide limits. In general, one works so that an about 3 to 40 wt .-% percarboxylic acid in the organic Solvent is obtained. An organic extract containing 5-30% by weight of percarboxylic acid is preferably obtained. the The number of extraction stages should accordingly be as high as possible. In general, however, one extraction unit is sufficient with 3 to 10 theoretical extraction stages to produce the solutions with the desired concentration of percarboxylic acids. Of course, it is desirable to keep the raffinate of extraction stage (b) as free as possible from percarboxylic acid and To obtain carboxylic acid. In general, however, it is sufficient if not more than 0.5% by weight of carboxylic acid in the raffinate and percarboxylic acid remain.

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A percarboxylic acid is used for the process according to the invention whose corresponding carboxylic acid boils higher than the vinyloxirane and an organic solvent that has a boiling point possesses, which is either higher than the boiling point of the percarboxylic acid corresponding carboxylic acid, or between the boiling point of vinyloxirane and that of the carboxylic acid. But it is also possible to choose the solvent so that its boiling point is below the boiling point of vinyloxirane. As an inert, organic solvent for the percarboxylic acid of the compounds already listed, preference is given to using a solvent which is at normal pressure at least 5 ° C above the boiling point of vinyl oxirane and at least 20 ° C below the boiling point of percarboxylic acid corresponding carboxylic acid boils. In addition, the percarboxylic acid or the carboxylic acid corresponding to it is selected and the solvent for the process according to the invention advantageously such that within the combination of carboxylic acid / solvent / vinyloxirane no pronounced azeotropes of a binary or ternary nature occur.

The temperature during the extraction can be varied within wide limits . In general, temperatures of 10 to 70 ^° C. are used. It is expedient to choose the same temperature as for the recovery of the percarboxylic acid according to (a), so that the other temperatures listed for reaction step (a) can also be used for extraction (b). As far as the pressure is concerned, normal pressure, reduced pressure or else elevated pressures can be used.

The known extraction systems are used as extraction units in question, which enable a multi-stage countercurrent extraction.

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Mixer-separators, sieve bottom extractors, pulsed, for example, are suitable Sieve tray columns or spray columns. But you can also use single-stage or multi-stage centrifugal extractors.

The organic extract contains the percarboxylic acid and the Carboxylic acid nor small amounts of free hydrogen peroxide, water and traces of the acid used as a catalyst, e.g. Sulfuric acid. The raffinate essentially contains the unreacted hydrogen peroxide and the acidic catalyst.

The raffinate of the extraction, which essentially contains water, hydrogen peroxide and, for example, sulfuric acid as the acidic catalyst, is then reprocessed for the conversion of the carboxylic acid and hydrogen peroxide in process step (c) by concentrating it entirely or partially by removing water in a distillation. The amount of water to be distilled off from the raffinate stream fed in from this concentration corresponds essentially to both the amount of Y.'asser that was formed in the reaction of hydrogen peroxide with the carboxylic acid according to (a) and the amount of water that was used with the fresh hydrogen peroxide to supplement the amount consumed is required, is introduced into the process. The top product of the distillation is water, which can extract a small amount of hydrogen peroxide, percarboxylic acid and carboxylic acid. In general, the resulting distillation under impeded by pressure, for example at pressures of 10 to 250 Torr, preferably UO to 150 Torr, and at temperatures in the bottom of UO to 12O ⁰ C, preferably from 60 to 85 ° C. In general, the entire raffinate stream leaving the extraction is also suitable for concentration if the extraction is carried out in a single extraction unit. However, it is also possible to extract the reaction mixture obtained according to (a) in, for example, two extraction units

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both the raffinate from the first and the raffinate from the add the second extraction stage to the concentration. Used for an extraction that takes place in two extraction units the refinement of the first unit is divided into a larger and a smaller partial flow, so basically each of these is Portions suitable for concentration. In the case of an extraction consisting of two extraction units, extraction is advantageously carried out, in which the raffinate leaving the first unit is divided into a small and a larger substream and the smaller portion is fed into the second unit, the raffinate from the second extraction unit of the distillation for concentration.

The fresh hydrogen peroxide to supplement the quantities used can be added in any concentration. It is advisable to use commercially available, e.g. 30 to 90 Cew. Parts aqueous hydrogen peroxide, to which the usual stabilizers can be added. For example, stabilizers such as those in Cmelin's "Handbuch der inorganic Chemie", β. Edition, Oxygen Tape, Delivery 7, 1966, listed on page 2274 and page 2275.

The fresh hydrogen peroxide can be mixed with the raffinate to be concentrated before it enters the distillation unit mixing the extraction according to process step (b); the two mass flows can also be fed separately into the distillation unit. It is also possible to add the fresh hydrogen peroxide to the raffinate after the concentration has taken place. You can also add part of the fresh hydrogen peroxide to the raffinate before the concentration and the rest Add the amount of fresh hydrogen peroxide to the raffinate after the concentration has taken place.

But you can also put the fresh hydrogen peroxide directly into the Implementation according to (a) entered, or else mix it with the raffinate portion of the extraction that is not concentrated. As a distillation unit, it is expedient to use a column provided with a condenser and an evaporator unit.

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The well-known tray columns or are used for the distillation Pull body columns in question. The number of distillation stages is chosen so that the top product contains as little hydrogen peroxide as possible. It is desirable to use less than 0.1 wt To get hydrogen peroxide in the condensate. The known evaporators are basically suitable as the evaporator unit. For example, those evaporator units are suitable in which the residence time of the product is less than 20 minutes, preferably less than 10 minutes. Falling-film or thin-film evaporators are particularly suitable Materials for the Deetillationseinhelt are high-alloy, rust-free · stainless steels, which in addition to iron essentially still Chromium and nickel contain, such as a material with the DIN designation 1.4571, which in addition to iron 17.5 wt Chromium, 11.5 Cew.-Jt nickel, 2.25 Cew.-Jt molybdenum, and up to 2 wt% manganese, up to 1 wt% silicon, up to 0.1 wt% Contains carbon and small amounts of titanium, or a material which, in addition to Elsen, contains 25% by weight of chromium, 25% by weight of nickel, 2.25 Parts by weight molybdenum and up to 2 parts by weight manganese, up to 1 part by weight Silicon, contains up to 0.06% by weight of carbon and small amounts of titanium and is designated with the number 1.4577 according to DIN will. Particularly suitable materials for the distillation unit, in particular for the evaporator, are zirconium, zirconium-containing material and zinc fillers.

The bottom product of this distillation unit is - if necessary, restoring the concentrations of hydrogen peroxide and hydrogen peroxide required for the reaction with the carboxylic acid Catalyst - returned to the reaction stage (a). As a result of this measure, the raffinate of the extraction is returned to the reaction stage according to (a), it being previously completely or partial dl concentration according to (c), one essentially obtains the process steps (*), (b), (e), and (d) comprehensive cycle of hydrogen peroxide and catalyst. It can be useful to add a part, e.g. 0.1 up to 6 wt. Jt, of the circulatory stream from time to time or even

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IS 273424Q

to be taken continuously as a side stream from the process. This side stream is advantageously taken off at one Point of the process where the circulating stream has the lowest possible concentration of hydrogen peroxide and acidic catalyst and optionally of percarboxylic acid and carboxylic acid. The raffinate of the extraction before the addition of Fresh hydrogen peroxide and prior to concentration according to (c). This side stream, as part of the recycle stream represents an aqueous solution containing essentially hydrogen peroxide and acidic catalyst, can either be discarded or passed to a regeneration stage for work-up. A regeneration of this part of the Circulation stream can be done, for example, so that you can Hydrogen peroxide contained therein is distilled off in vacuo with steam, with an aqueous residue as the distillation residue Solution of the acidic catalyst is obtained. The aqueous solution containing hydrogen peroxide obtained as a distillate can if necessary after concentrating, can be returned to the process. The aqueous solution of the acid catalyst can after purification, for example by distillation, can also be returned to the process. This cycle exchange removes a corresponding part of the catalyst, e.g. sulfuric acid, from the process, which must therefore be supplemented in the process.

The organic extract containing essentially the percarboxylic acid and the carboxylic acid, which according to process step (b) is obtained, is treated in process step (e) with water or an aqueous solution. In general one proceeds in such a way that the organic percarboxylic acid extract is in one of the usual devices washes with water.

It is advisable to carry out this washing as an extraction, e.g. as a multi-stage countercurrent extraction, with water, for example

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in a three-stage extraction unit. Instead of countercurrent extraction, it is of course also possible to use cocurrent or cross-current extraction. When working with several extraction stages, the extraction can also be carried out partly in cocurrent and partly in countercurrent.

Kan conveniently uses 0.1 to 10 volumes -56 of water or aqueous solution, based on the organic extract. It is preferable to use 0.5 to 7 volume Jo of water. An aqueous solution can also be used instead of pure water use which is essentially free of hydrogen peroxide and mineral acid. It is useful to use an aqueous To use phase that arises in the process. This is suitable, for example, when carrying out the process step (d) recovered distillate. The aqueous phase of the water treatment can be returned to the extraction according to (b) in order to to obtain the proportions of percarboxylic acid, carboxylic acid and hydrogen peroxide contained therein for the process.

The known extraction systems are suitable as devices for the water treatment according to process step (e), e.g. mixer-separators, sieve bottom extractors, pulsed Sieve tray columns or extraction centrifuges.

After treatment of the organic solution of the percarboxylic acid with water or an aqueous solution according to (e) one obtains an essentially hydrogen peroxide and Sulfuric acid-free, organic solution of the percarboxylic acid, which is now subjected to azeotropic distillation according to process stage

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(f) is subjected to removing water contained in the organic solution. The water content of the for Drying organic solution is generally 0.5 to 7 wt. #. This water content is essential both on the nature of the particular organic solvent used and on the chosen concentration Percarboxylic acid in the extract obtained according to (b) dependent.

The entrainer used to remove water from the organic solution of the percarboxylic acid by azeotropic distillation is generally the inert organic solvent. But £ 3 is also possible to use another suitable entrainer of the organic solution of the percarboxylic acid before it enters the Process stage (f) or directly into the distillation unit add according to (f) and carry out the azeotropic distillation with this.

In process stage (f), the amount of distillate is generally used chosen so that the residual water content in the bottom product the azeotrope column less than 0.5 wt .-%, preferably less than 0.2 wt%, e.g. 0.05-0.2 wt%. But it is also possible to reduce the water content to a negligible level reduce small value. The abrasive which separates out as an organic phase after the condensation of the azeotrope column is carried out the column as reflux. The aqueous phase obtained after condensation of the overhead vapors, which are generally small amounts of Contains percarboxylic acid, carboxylic acid and hydrogen peroxide, the process at a suitable point, for example fed back to the extraction according to (e) or (b); however, it can also be removed from the process.

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BATH ORIGINAL

273A240

The azeotropic distillation (f) can be carried out at normal or reduced pressure, for example at 200 to 400 Torr. The bottom temperature is, for example 30 to CO ⁰ C. In general, a bottom temperature of below 70 ⁰ C is sufficient.

The usual columns, for example the known tray or packed columns, are suitable for the azeotropic distillation. The usual devices can be used as the evaporator. Downdraft or thin-film evaporators are particularly suitable.

The solution is now obtained as the bottom of the azeotropic distillation, organic a substantially water and hydrogen peroxide-free percarboxylic acid in process step _(o) with an excess of butadiene in a molar ratio of liutadien to percarboxylic acid of 1.5 to 6: 1 at temperatures of from ⁰ C to 80 ⁰ C and reacted at a pressure of 0.8 to 20 bar.

But you can also work at a pressure of 1 to 10 bar. A suitable pressure range is, for example, pressures from 1.2 to 8 bar. It is preferred to work at a pressure of 1.5 up to 5 bar.

The reaction temperature is preferably maintained at 10 to 70 ⁰ C. The reaction of butadiene with the organic solution of the percarboxylic acid is very particularly preferably carried out at temperatures from 20.degree. To 60.degree. In addition to the procedure under isothermal conditions, ie maintaining a uniform temperature in the entire reaction mixture, the reaction can also be carried out with the formation of a so-called temperature gradient, which generally increases as the reaction proceeds. However, the reaction can also be conducted in such a way that a gradient of falling temperature develops as the reaction proceeds.

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The pressure when carrying out process step (g) is expediently chosen so that the reaction mixture is essentially in the liquid phase. At a molar ratio of butadiene to percarboxylic acid of, for example 2.5: 1 and at a reaction temperature of 40 to 50 ° C. the pressure is, for example, 2 to 3.5 bar.

The col ratio of butadiene to percarboxylic acid is preferably 1.5 to 4: 1. Is particularly beneficial it is to use a molar ratio of 2.0 to 3 »0 mol of butadiene per mol of percarboxylic acid.

To carry out the reaction, the devices customary for reactions of this type can be used, such as agitator kettles, Tube reactors, loop reactors or loop reactors. Generally one uses a device that behaves like a Cascade of at least two ideally mixed boilers behaves. It is particularly advantageous to use a reaction system that feels like a cascade of 4 to 50, preferably 10 to 30, ideally mixed boilers behaves. In the practical To carry out the implementation, for example, a series of several agitator vessels, for example a cascade of 3 to 6 tank reactors.

For the reaction according to process step (g), in general technical butadiene used. It can contain the additives customary in industrial use, in particular n-butenes.

The 3utadiene can be introduced into the reaction unit in various ways. You can get the butadiene in liquid

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or in gaseous form. The butadiene can also be put into the reactor unit together with the percarboxylic acid solution conduct. It is also possible to use both input materials separately from one another are introduced into the reactor. It is also possible to mix the butadiene and the percarboxylic acid solution at different levels Place in the reactor unit to direct. When using several reactors connected in cascade, it can be expedient to introduce all of the butadiene into the first reactor. But you can also use the butadiene on the different Divide reactors.

The considerable heat of reaction is dissipated by internal and external coolers. To dissipate the heat of reaction, the reaction can also be carried out under reflux, ie in boiling reactors. The reaction is expediently carried out with as complete a conversion of the percarboxylic acid as possible. In general, more than 98 % of the percarboxylic acid is converted. It is useful to implement more than 99 % percarboxylic acid. The reaction can be carried out with a particularly high selectivity if it is carried out partially in a reaction tube through which a turbulent flow flows and which is connected, for example, to the series of stirred tanks. It is particularly favorable to use a reaction tube which is equipped with internals which largely prevent backmixing, for example perforated transverse trays. For example, the reaction is first carried out in a few, for example 1 to 3, stirred reaction units connected in series and the reaction mixture is then passed into a reaction tube to complete the reaction. The reaction tube can be operated under adiabatic conditions; but you can also cool, for example by external cooling, or you can attach coolers between individual pipe sections. The dimensioning of a suitable reaction tube depends on

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the intended throughput. It is essential that the flow velocity in the reaction tube is so high that that backmixing of the reaction components is essentially excluded. The diameter of the reaction tube can be 0.01 to 10 meters with a length of 1 to 200 meters. You can also operate several pipes in parallel. For example, tube bundles can also be used. If a reaction tube with perforated transverse trays is used, the transverse trays Io are generally at a distance from 0.1 to 5 m from each other.

When carrying out the reaction between butadiene and the percarboxylic acid (step g) according to the invention, it is possible to achieve vinyloxirane yields of over 95 %, based on the percarboxylic acid used. The amount of by-products, for example butene (1) diol (3,4) and its mono- and diesters with the carboxylic acid corresponding to the percarboxylic acid, is less than 2,96, based on the vinyloxirane formed. The amount of polymerized butadiene, based on the total amount of butadiene used in the reaction stage according to (g), is less than 1% by weight.

The reaction mixture is worked up by distillation Ways whereby pure vinyloxirane is obtained and excess butadiene, the carboxylic acid and the organic solvent in is isolated to such a degree of purity that it can be returned to the process, which may also only be partially carried out. It is useful vinyloxirane and the To separate carboxylic acids from each other very quickly. A distillation column, for example, is used for this purpose Vinyloxirane and butadiene, optionally together with lower-boiling components and part of the solvent Head decreases and the remaining solvent and the carboxylic acid are obtained as the bottom product. The top product is

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if the butadiene is separated off by distillation In a further distillation column to obtain pure vinyloxirane worked up. From the swamps of these two The organic solvent and the carboxylic acid are recovered in the distillation columns. The distillation residue from the carboxylic acid distillation is the already mentioned small amount of higher boiling by-products. The organic solvent can in principle be recovered quantitatively.

In many cases it can be advantageous to add a stabilizer or a solution of a stabilizer to the reaction mixture leaving the process stage according to (g) before it enters the first distillation column. However, the reaction mixture can also be worked up by distillation without using a stabilizer. All compounds which are capable of binding oxygen or traces of peroxidic compounds are suitable as stabilizers. These compounds can also contain nitrogen and / or sulfur. Examples include hydroquinone, 4-tert-butylpyrocatechol, 2,6-di-tert-butyl-4-methyl-phenol, phenothiazine, N, N-dimethylaniline, tetramethyl-hydroquinone, N-nitroso-diphenylamine, pyrogallol, 2 -Hethyl-benzothiazole, 6-methoxy-2-aminobenzothiazole _f 2,3-dihydroxyquinoxaline and the addition compound of diisobutylene and nitrogen oxide.

One embodiment of the method according to the invention will be explained with reference to FIG.

In the first reaction stage (1) are simultaneously via (2) one Aqueous solution containing 30 to 40% by weight sulfuric acid and 25 to 35% by weight hydrogen peroxide and via (3) propionic acid in a molar ratio of hydrogen peroxide to propionic acid such as 0.9 to 1.2: 1 at a temperature of 25 to 45 ° C

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given. The residence time in the reaction system (1) is 10 to 30 minutes. The reaction mixture which leaves the reaction system (1) via (4) contains approx. 26 to 32 % by weight perpropionic acid, 12 to 17% by weight propionic acid, 17 to 21% by weight sulfuric acid, 5 to 8 % by weight hydrogen peroxide and 2 to 5 wt.% Caro's acid. It reaches an extraction system (5), which consists of a pulsed sieve tray column with 60 to 90 sieve trays and which is charged with benzene with a propionic acid content of less than 0.5 % via (6). The raffinate of this extraction, which is discharged from the extraction system (5) via (7), contains the hydrogen peroxide and the sulfuric acid which have not reacted in the reaction system (1). It is, together with about 50% - directed igcra commercially available aqueous hydrogen peroxide, which is fed through (9), which consists of the evaporator and the column distillate desk unit (8) in which at 40-120 Torr, and a bottom temperature of 60 to 80 ⁰ C so much water is withdrawn overhead that an aqueous solution containing 30 to 40% by weight of sulfuric acid and 25 to 35% by weight of hydrogen peroxide is obtained as the bottom product, which is returned to the reaction system (1) via (2). The water withdrawn overhead in the distillation unit (8) is withdrawn from the process via (10). The amount of water that is obtained as distillate corresponds essentially to the amount of water contained in the hydrogen peroxide used and formed in the process stage according to (a), that is to say in the reaction system (1). A FaIlstroraverdanpfer is used as the evaporation unit of the distillation column (8). The benzene perpropionic acid extract from the extraction system (5) is passed via (11) into the extraction system (12) consisting of 3 mixer-separators, where the extract is extracted in countercurrent with the water supplied via (13). The amount of water is 3 to 6 percent by volume of the benzene solution. The aqueous phase of this extraction unit (12) is returned to the extraction unit (5) via (14).

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The water-treated benzene perpropionic acid solution passes via (15) into the distillation unit (16) where azeotropic dehydration is carried out. The pressure within the distillation system (16) is 100 to 300 Torr. The bottom temperature is 50 to 75 ⁰ C. The water content of the flowing out of the bottom of this column benzene Perproionsäure is less than 0.3 wt.%. The essentially water- and hydrogen peroxide-free benzene perpropionic acid obtained as the bottom of the azeotropic distillation is passed via (17) into the reaction system (18), where the reaction with butadiene takes place in a molar ratio of butadiene to perpropionic acid of 2 to 4: 1. The butadiene enters the reaction system (18) via (19), (20) and (22). The pressure in (18) is 3-5 bar. The reaction system (18) consists of 2 series-connected loop reactors with a downstream residence time tube of 10 to 8ΰ m in length. The temperature in the two loop reactors, the reactant is carried out by means of the circulation pump in drnen Durchraischling, is from 20 to 50 ⁰ C. The perpropionic acid is thereby converted to 80 to 95%. The further reaction of the perpropionic acid up to a conversion of 99.8 % takes place in the downstream residence time tube, which is operated without cooling. The reaction mixture obtained is passed via (23) into an expansion vessel (21) and depressurized there. The gas phase obtainable here essentially contains butadiene, which is returned to the reaction with perpropionic acid via (22). From the liquid phase, which reaches the distillation unit (25) via (24), vinyloxirane is first separated off by distillation together with butadiene and with part of the benzene. The stream containing butadiene, vinyloxirane and benzene is fed via (26) to the distillation unit (27), where the further separation of the components takes place and pure vinyloxirane is obtained, which leaves the process via (28). Butadiene is returned to the reaction system (18) via (20). The bottoms of columns (25) and (27) are fed via (29) and (30) to a further distillation unit (31), where benzene is recovered as the top product and returned to the extraction system (5) via (6). Of the

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Essentially consisting of propionic acid bottom of the benzene Rückgewi The extension column (31) is fed via (32) to the distillation unit (33) in which propionic acid is distilled off as the top product which is returned to the reaction system (1) via (3). The products that boil higher than propionic acid are obtained as the bottom product of the distillation (33) and discharged via (34).

According to the process according to the invention, vinyloxirane can be produced in yields of at least 90 %, based on the hydrogen peroxide used, and at least 95 % _t, based on the butadiene used.

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Example 1 (see also Fig. 2)

Through the reaction system (1), which consists of a heated dwell tube 55 cm long and 5 cm in diameter, provided with packing elements, 1034 g of a mixture of 415 g (-5.6 mol) propionic acid and 619 g per hour an aqueous solution which contains 37.6% by weight of sulfuric acid and 30.8% by weight of hydrogen peroxide (= 5, e> mol of H ₂ O ₂ ).

In the aqueous solution containing hydrogen peroxide and sulfuric acid, some of these components are present as Caro's acid. This part is 5.8% by weight , based on the total amount of the aqueous solution, for which the following composition results:

32.8 % by weight of free sulfuric acid, 29.1 % by weight of free hydrogen peroxide and 5.8% by weight of Caro's acid. The molar ratio of hydrogen peroxide to propionic acid in the mixture entering reaction system (1) is 1: 1, the hydrogen peroxide bound in Caro's acid being calculated _{as free H 2} O _2.

Within the reaction system (1) the existing now consists of propionic acid, sulfuric acid, hydrogen peroxide, water, and Caro's acid mixture is about 18 minutes heated to 4O ⁰ C during which time the propionic acid is about 59% reacted to perpropionic acid. After passing through the residence time tube, the average is 28.8 % by weight of perpropionic acid, 16.5% by weight of propionic acid, 19.6% by weight of sulfuric acid, 3.47% by weight of Caro's acid, 6.54% by weight of hydrogen peroxide and 25% by weight , 1% by weight of water containing product streams (1034 g per hour) are cooled to room temperature and passed into a gas separator, where 166 ml of a gas consisting of 87 % oxygen and 13 % carbon dioxide escape per hour. Then, the mixture is degassed, after having combined it with the running of the Extraktioneeinheit (12) mixture of the two aqueous phases, the extraction system

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(5) supplied. The extraction process is carried out at a temperature of 32 ° C. The extraction system used is a pulsed sieve tray column with 80 sieve trays, a length of 4 m and a diameter of 25 mm, as well as a separation vessel at the top and bottom, in which the phase separation takes place. At the upper end of the column (5) the product stream obtained after degassing and combined with the mixture of the aqueous phases of the extraction system (12) fed in via line (14) is added, which flows through the column from top to bottom as a heavy phase, while on at the bottom, the benzo serving as an extractant, which contains 0.09% by weight of propionic acid and traces of water, is introduced into the column at an amount of 1092 ml per hour (= 961 g / h). From the upper separating vessel is withdrawn hour 1585 ml of a benzene solution of Perpropionsßure (= 1490 g / h), which in addition to 21.4 wt.% Perpropionic acid 12.6 wt.% Propionic acid, 0.97 Gew.j6 water , o, containing 51 wt.% hydrogen peroxide and traces of sulfuric acid.

The raffinate from the extraction collects as a heavy phase in the lower separating vessel and is continuously removed from there via line (7). This raffinate obtained with an amount of about 5Ö7 g per hour, contains an average of 34.58 wt.% Sulfuric acid, 11.16 wt.% Hydrogen peroxide, 6.12 Gew.?i Caro's acid, and 0.1 wt. # Propionic acid and 0.06% by weight perpropionic acid. This raffinate is prepared for the reaction with propionic acid by adding 195.6 ml of a 50 μl aqueous solution of hydrogen peroxide (= 117 g >> 3.44 mol H ₂ O ₂ ) per hour via (9) and the resulting Geraisch concentrated again by distilling off 202 g of water. This concentration process takes place in the distillation unit (8), which consists of a column provided with bubble-cap trays (length = »1 m, diameter * 50 mm), a condenser, a device that allows the reflux ratio to be varied, and a falling film evaporator , which can be heated with the vapors of a boiling liquid,

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exists and is operated at a pressure of 50 torr. The mixture consisting of the raffinate from the extraction (5) and the aqueous solution of hydrogen peroxide is introduced into the lower part of the column (8). At a bottom temperature of 68 70 ⁰ C, a temperature at the top of the column of 32 ⁰ C and a reflux ratio of 0.7 (reflux / extraction) in the hour 202 ml of water distilled over. This distillate contains traces of hydrogen peroxide and 0.2% by weight perpropionic acid and 0.3% by weight propionic acid. 619 g per hour of an aqueous solution, which in turn contains 32.8% by weight of sulfuric acid, 29.1% by weight of hydrogen peroxide and 5.0% by weight of Caro's acid, are withdrawn from the bottom of the column via line (2). This mixture, after being cooled to room temperature, is returned to the reaction system (1).

From the thus formed, the reaction and extraction system (1) or (5), as well as the distillation unit (8) comprising circulating stream of hydrogen peroxide and sulfuric acid, about 4.5 g per hour as raffinate of the extraction (5) are discharged. The resulting loss of sulfuric acid in the circuit is supplemented by continuously introducing the same blade of a mixture containing the composition of the raffinate from the extraction (5 ) into the circuit upstream of the distillation unit (8) every hour.

The loss of hydrogen peroxide resulting from this cycle exchange is 0.5 %, based on the fresh hydrogen peroxide used upstream of the distillation unit (8).

The light phase removed from the extraction system (5) Benzene solution of perpropionic acid is via line (11) dom extraction system (12), which is a three-stage one above the other arranged mixer-separator battery consisting of each a mixing pump with a subsequent separating vessel with a capacity of about 2 liters is fed and runs through the System from bottom to top.

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BATH ORIGINAL

The mixing pump of the lower stage is fed in addition to the benzene solution of perpropionic acid per hour 67 ml of an aqueous solution that is obtained when the water phase of the top product of the subsequent azeotropic distillation (distillation unit (16)), which is in an amount of 60 ml per Hours and 1.48% by weight of H ₂ O ₂ * 2.43% by weight of perpropionic acid and 0.27 % propionic acid contains, mixed with 7 ml of deionized water. The benzene solution, which is removed from the lower separating vessel as a light phase, is fed to the mixing pump belonging to the upper mixer-separator unit together with 17 ml / h of fresh water after it has passed through the middle mixer-separator arrangement. The aqueous phase obtained here after phase separation has taken place is passed into the middle extraction stage. The aqueous solutions that collect as the heavy phase in the middle and lower separating vessel are combined and returned to the extraction unit (5) via (14) so that this stream, consisting of an aqueous Looun ^ containing 25.23 wt. Ji contains perpropionic acid, 6.8 wt.% hydrogen peroxide and 22,35 Gew.Ji propionic acid, in an amount of 81 ml / h immediately prior to entry into the pulsed sieve tray column (extraction system (5)), with which from the reaction system (1) incoming product stream (4) mixes.

From the members of the upper mixer settler unit separating vessel of the extraction system (12) via line (15) as the light phase in the hour 1493 g ( "1570 ml) of a benzene solution of perpropionic acid with the composition 20.04 wt.% Perpropionic , 11.41% by weight of propionic acid, 3.95% by weight of water and 0.2% by weight of hydrogen peroxide are drawn off and introduced into the distillation unit (16), where the solution is azeotropically dried. Before entering the distillation unit (16), the benzene solution of perpropionic acid is mixed with 5 ml of an approximately 3% strength by weight solution of a stabilizer of the type of commercially available sodium salts of partially esterified polyphosphoric acids in propionic acid per hour.

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The distillation unit (16) is operated at 210 Torr and consists of a thin film evaporator, a 50 cm long column with 5 bubble trays of 50 mm diameter, a condenser and a separator for phase separation of the distillate at the top of the column. The temperature in the bottom of the column is 65 ^° C. The distillate obtained per hour is 60 roles of water and about 915 ml of benzene. The benzene is fed into the column as reflux, while the water obtained in the separator, as already described, is introduced as washing water via (35) into the lower stage of the extraction unit (12) . The bottom product of the azeotropic distillation is obtained in an amount of 1438 g per hour of a 20.71 wt. # - sodium benzene solution of perpropionic acid, further 12,18% by weight of propionic acid, and 0.1 Gew.Ji water and 0.15. Weight 9 <contains hydrogen peroxide.

The yield of perpropionic acid in the benzene extract dried in this way is 96.15 % based on the hydrogen peroxide used in the process.

The dried benzene solution of perpropionic acid thus obtained is reacted with excess butadiene in a four-stage tank cascade (reaction system (18)). The reaction is carried out at a pressure of 2 bar. The butadiene is fed into the first reactor in gaseous form via lines (22), (20) and (19). The excess of butadiene, based on the perpropionic acid used in the reaction , is a total of 170 Hol. % (= 482 g butadiene). The first reactor of this four-stage cascade, which, like the three subsequent reac tion vessels, is provided with a stirrer and has a capacity of 1600 ml, is at a temperature of 35 ° C, the second, third and fourth reactor at a temperature of 40 ° C operated.

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BAD ORIGtNAL

The perpropionic acid used is converted to 99.8 Ji under these reaction conditions. After the fourth reactor, the reaction mixture, which is obtained in an amount of 1920 g per hour and has an average composition of 15.62% by weight of butadiene, 11.67% by weight of vinyloxirane, 21.46% by weight of propionic acid and 50 % 08 Geu.% Benzene and 0.13% by weight water, after cooling to 30 ° C in the separator (21) expanded to normal pressure, with a small part of the butadiene (37 g / h) outgassed via (22) the Reaction system (16) is fed back. After 2.0 g of 4-tert-butyl-pyrocatechol have been added, the mixture obtained after decompression is now fed to a first distillation column (25), where all of the vinyloxirane is fed together with the butadiene and part of the benzene decreases as distillate. This distillate is obtained, which contains an average of 32.6 wt.% Butadiene, vinyloxirane Gew.Si 27.25, 39.9 Gew.tf benzene and small amounts of water and g in an amount of 822 per hour, one to the distillation column ( 27) via (26), where 224 g of a 99.9 % vinyloxirane (product stream 28) and 268 g of butadiene are obtained per hour, which is fed into the reaction system (18) via line (20). The bottom products of columns (25) and (27) are fed via line (29) or (30) to column (31), where the benzene is recovered as top product at an amount of 961 g / h and then via line (6) is fed back into the extraction system (5). The bottom of the column (31) reaches the distillation column (33) via line (32). The top product here is 415 g / h of propionic acid per hour, which are returned to the reaction system (1) via line (3). From the bottom of the column (33), 15 g per hour of a mixture of higher-boiling compounds are discharged via (34) which essentially contains butene (1) diol (3,4) mono- and dipropionate .

The yield of vinyloxirane is therefore 96.7% , based on the perpropionic acid used in the reaction system (18). or based on hydrogen peroxide used in the process in (8) via (9), 93 %.

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-u-

eersei t e

Claims (34)

claims 2/34240 Process for the production of vinyloxirane from hydrogen peroxide and butadiene, characterized in that that he a%) a 10 to 45 wt of a water soluble acid catalyst and 20 to 50 Gew.jG hydrogen peroxide-containing aqueous solution with a 2 to 5 carbon atoms containing carboxylic acid in a molar ratio of hydrogen peroxide to carboxylic acid, such as 0.5 to 30. 1 at temperatures of 10 converts to 70 ⁰ C, b) the reaction mixture obtained is extracted with an inert, organic solvent in countercurrent, c) all of the aqueous raffinate of the extraction, which essentially contains hydrogen peroxide and acidic catalyst or partially concentrated by removing water by distillation, d) the concentrated raffinate and optionally Unconcentrated portion of the raffinate while restoring that required for the reaction with the carboxylic acid Concentrations of hydrogen peroxide and water-soluble acidic catalyst returned to the reaction stage (a), with the purpose of recovery the hydrogen peroxide concentration required for the reaction with the carboxylic acid according to the proportion of the raffinate to be concentrated before or after the removal of water by distillation (c) is added or is added to the possibly non-concentrated part of the raffinate, e) containing essentially percarboxylic acid and carboxylic acid organic extract treated with water or an aqueous solution and Le A 18 268 - 36 - 809886/0341 ORIGINAL INSPECTED f) the now practically hydrogen peroxide-free, water-containing, organic extract subjected to an azeotropic distillation in such a way that the residual water content in the bottom product the azeotrope column is less than 0.5 wt. g) the organic solution now obtained, containing percarboxylic acid and carboxylic acid, with excess butadiene at a molar ratio of butadiene to percarboxylic acid of 1. '} to 6: 1 at temperatures from 0 ^° C. to 80 ^° C. and at a pressure of 0 , 8 bar to 20 bar converts, and h) the vinyloxiranhaltige reaction equipment on distillative Working up ways, with pure vinyloxirane being isolated and the excess butadiene, the carboxylic acid and the inert, organic solvents are recovered and wholly or partially returned to the process. 2. The method according to claim 1, characterized in that one sulfuric acid is used as the water-soluble acidic catalyst in step (a). 3. The method according to claim 1 and 2, characterized in that one uses in step (a) a 20 to 43 wt.% Sulfuric acid and 22 to 35 wt.% Hydrogen peroxide-containing aqueous solution. 4. The method according to claim 1 to 3, characterized in that in step (a) hydrogen peroxide and carboxylic acid in one Molar ratio of 0.5 to 1.3 or 3.5 to 25: 1 is used. 5. The method according to claim 1 to 4, characterized in that in step (a) the Ui
is carried out. in stage (a) the reaction at temperatures from 20 to 60.degree Le A 18 268 - 37 - 8 0 9 8 8 6/0. 6. The method according to claim 1 to 5, characterized in that in stage (a) the carboxylic acid is acetic acid, propionic acid, n-butyric acid or isobutyric acid is reacted. 7. The method according to claim 1 to 6, characterized in that propionic acid is used as the carboxylic acid in step (a) 8. The method according to claim 1 to 7, characterized in that in stage (b) as an inert organic solvent, chlorinated hydrocarbons, aromatic hydrocarbons, esters or Ether can be used. 9. The method according to claim 1 to 8, characterized in that in step (b) as the inert organic solvent 1,2-dichloropropane, Chlorobenzene, toluene, benzene, n-butyl acetate or diisopropyl ether is used. 10. The method according to claim 1 to 9, characterized in that in step (b) the quantitative ratio of inert, organic Solvent for the reaction mixture obtained in step (a) and containing the percarboxylic acid is selected as 4 to 0.3: 1. 11. The method according to claim 1 to 10, characterized in that an organic solution containing 5-30 wt .-% percarboxylic acid is obtained in step (b). 12. The method according to claim 1 to 11, characterized in that the extraction according to (b) is carried out so that the raffinate of the extraction according to (b) contains no more than 0.5 wt .-% carboxylic acid and percarboxylic acid. 13. The method according to claim 1 to 12, characterized in that the organic solvent used for the percarboxylic acid is a solvent which boils at normal pressure at least 5 ° C above the boiling point of vinyloxirane and at least 20 ° C below the boiling point of the carboxylic acid corresponding to the percarboxylic acid . Le A 18 268 - 38 - 809886/03 * 1 14. The method according to claim 1 to 13, characterized in that one extracts ^{at temperatures of 10 to 7O 0 C in step (b).} 15. The method according to claim 1 to 14, characterized in that one in step (c) the distillative removal of water at pressures of 40 to 150 Torr and at temperatures of 60 to 85 ° C. 16. The method according to claim 1 to 15, characterized in that one in step (c) in the distillative concentration Water containing less than 0.1% by weight hydrogen peroxide distilled off. 17. The method according to claim 1 to 16, characterized in that from the raffinate of step (b) a side stream in a Amount of 0.1 to 6 wt.% Of the circulating stream withdraws. 18. The method according to claim 1 to 17, characterized in that the side stream containing hydrogen peroxide and sulfuric acid is used a regeneration stage and optionally the recovered proportions of hydrogen peroxide and sulfuric acid re-enters the procedure. 19 · Method according to Claims 1 to 18, characterized in that in step (e) the organic extract is treated with water in an amount of 0.5 to 7 Vol.Ji of the organic extract. 20. The method according to claim 1 to 19, characterized in that in step (e) the organic extract with the aqueous Treated phase from the azeotropic distillation of stage (f). 21. The method according to claim 1 to 20, characterized in that one obtained in step (e) in the water treatment recirculates the aqueous phase to process stage (b). Le A 18 268 - 39 - 809886/0341 22. The method according to claim 1 to 21, characterized in that the azeotropic distillation of stage (f) is carried out at 30 to 80 ⁰ C and 200 to 400 Torr. 23. The method according to claim 1 to 22, characterized in that in step (f) the residual content of water in the bottom of the azeotrope column is less than 0.2 wt. #. 24. The method according to claim 1 to 23, characterized in that in step (g) the reaction at a molar ratio of butadiene to percarboxylic acid of 1.5 to 4: 1 is carried out. 25. The method of claim 1 to 24, characterized in that one carries out the reaction of step (g), at temperatures of 20 to 60 ⁰ C. 26. The method according to claim 1 to 25, characterized in that the reaction of step (g) at a molar ratio of Butadiene to percarboxylic acid as 2 to 3: 1 carries out. 27. The method according to claim 1 to 26, characterized in that the reaction of step (g) is carried out in a reaction system, which behaves like a cascade of 10 to 30 perfectly mixed boilers. 28. The method according to claim 1 to 27, characterized in that the implementation of stage (g) in a cascade of 3 to 6 boiler reactors performs. 29. The method according to claim 1 to 28 , characterized in that the reaction of step (g) is carried out at least partially in a tubular reactor. 30. The method according to claim 1 to 29, characterized in that dan the reaction of stage (g) is partially carried out in a residence time tube equipped with perforated transverse bottoms. Le A 18 628 - 40 - 809886/0341 (ο 31. The method according to claim 1 to 30, characterized in that the reaction mixture aua of step (g) in step (h) worked up by distillation. 32. The method according to claim 1 to 31, characterized in that the reaction mixture from step (g) in step (h) by distillation in vinyloxirane, butadiene, organic solvent and carboxylic acid is separated. 33. The method according to claim 1 to 32, characterized in that daij the organic solvent obtained in step (h) in step (b), the carboxylic acid obtained in step (h) in step (a) and the butadiene obtained in stage (h) can be returned to stage (g). 34. The method according to claim I to 33, characterized in that the reaction mixture obtained according to step (g) before the gem.ii. Step (h) taking place, separation by distillation, a stabilizer or the solution of a stabilizer is added. Le A 18 268 - 41 - 809886/034