DE1079047B - Process for separating diisopropylbenzene dihydroperoxides from their mixtures with diisopropylbenzene and its oxidation products - Google Patents

Description

GERMAN

The invention relates to a method for separating diisopropylbenzene dihydroperoxides, in particular the m- and / or p-isomers of this compound from mixtures which diisopropylbenzene and diisopropylbenzene monohydroperoxide. Such mixtures are z. B. obtained by oxidizing of diisopropylbenzene with air or oxygen.

It is known from British Patent Specification 727,498 already known, such mixtures by treatment with non-acidic aqueous solutions, ie solutions having a p _H-W <ert of more than 7, in particular with an aqueous 4 ° / o aqueous sodium hydroxide solution to chemically separate. The diisopropylbenzene dihydroperoxide can be obtained from the alkaline extract of the mixture, for example by acidification with a stronger acid or carbon dioxide, whereby the dihydroperoxide of the diisopropylbenzene is precipitated.

The disadvantage of this separation with aqueous alkaline solutions is that the hydroperoxide is extracted not as such, but as the sodium salt, from which the dihydroperoxide must be made free with an acid or carbon dioxide. Another disadvantage is that the resistance of diisopropylbenzene monohydroperoxide due to the presence of aqueous alkaline Solutions is adversely affected.

There has now been a process for separating diisopropylbenzene dihydroperoxide from the above Found mixtures, after which the separation by extraction with hydrous organic Liquids is possible and in which the disadvantages mentioned above are avoided. The new process consists in that the said peroxides containing mixture with two Removes solvents that move in countercurrent and are only slightly soluble in one another, whereby that one solvent consists of a practically neutral, aqueous liquid that is 0 to 80 percent by weight of an alkanol containing no more than 2 carbon atoms in the molecule, while the other solvent is a liquid hydrocarbon.

The process can be carried out continuously or batchwise in the known extension devices, e.g. B. in a device consisting of mixing and separation vessels or in an extraction column, e.g. B. a column filled with Raschig rings or a column equipped with perforated plates. The so-called "rotating disc contactor" can expediently be used, as it is e.g. B. is described in Dutch patent specification 67,932. This device consists of a cylindrical vessel, which is separated using deflection rings
of diisopropylbenzene dihydroperoxides

from their mixtures with diisopropylbenzene and its oxidation products

Applicant:

NV De Bataafsche Petroleum
Maatschappij, The Hague

Representative: Dr. K. Sdiwarzhans, patent attorney,
Munich 19, Romanplatz 9

Claimed priority:
Netherlands 28 February 1957

Lucas Alders, Jan Pieter Fortuin,
Hendrik Mondria and Gerrit Hendrik Reman,

Amsterdam, Netherlands),
have been named as inventors

is equipped and in which a rotating shaft is arranged, on which several rotor disks are attached are. The inner diameter of the rings is larger than the diameter of the disks. Preferably is an extraction column, in particular the mentioned extraction device with rotating Discs, used.

One of the possible continuous modes of implementation is described below with reference to FIG Drawing explained. The extraction device 1 is provided with deflection ribs 2 and with rotor disks 3, which are mounted on a rotating shaft 4. The mixture to be extracted becomes the separation column fed through line 5 from an oxidation vessel (not shown) in which diisopropylbenzene is oxidized with the help of air. The essentially neutral, alcoholic-watery one Liquid ("extraction liquid") and the liquid hydrocarbon ("washing liquid") become the Separation column fed through lines 6 and 7, respectively.

As a result of the different specific gravity, the extraction liquid and the washing liquid flow past each other or through each other, the distribution of the mixture to be separated between Extraction and washing liquid through the rotating discs 3, which an intimate contact bring about between the liquids, is effected. The diisopropylbenzene dihydroperoxide on the one hand and diisopropylbenzene and diisopropylbenzene

309 76OTS1

monohydroperoxides, on the other hand, are preferred distributed over the extract or washing liquid.

If you consider the speeds at which the various liquids of the extraction device are supplied and discharged, adjusts so that the extract phase forms a coherent layer, separation into layers occurs in the upper part of the extraction device. If desired, can this can be promoted by a grid 8. The separated, washed-out constituents of the starting mixture are fed through line 9 to the distillation column 10, from which optionally a distillate is obtained under reduced pressure which consists essentially of the washing liquid, and which is fed into the separating device 16 via the line 11 and the cooler 12. The washing liquid, which diisopropylbenzene and diieopropylbenzene monohydroperoxide and any other oxidation products contains and is essentially free of diisopropylbenzene dihydroperoxide, is expedient returned through line 13 into the oxidation vessel (not shown).

The extract layer is passed through the line 14 into the distillation column 15, the separated Distillate (optionally obtained under reduced pressure and essentially extraction liquid contains) is passed through the line 17 and the cooler 12 into the separating device 16. The combined distillates separate in the separation vessel 16 into layers. The watery layer which is the extraction liquid, and the layer of washing liquid are passed through the pipe 19 and 20 returned to the extraction device. This returned in the cycle Extraction and washing liquid are mutually saturated at the extraction temperature.

The extract from which the extraction liquid has been removed is, if necessary after taking up a suitable one Solvent such as methanol or ethanol removed. It consists of purified diisopropylbenzene dihydroperoxide, which, for example, can be converted into the corresponding dihydric phenol can. By using suitable extraction conditions, the content of diisopropylbenzene and Diisopropylbenzene monohydroperoxide can be reduced to the desired value.

The diisopropylbenzene dihydroperoxide and the extraction liquid can be removed not only by distillation, but also by extracting the extract with a water-immiscible, low-boiling solvent for the diisopropylbenzene dihydroperoxide, e.g. B. with a low-boiling aromatic hydrocarbon such as toluene, or with a low-boiling ketone such as methyl isobutyl ketone, separated from each other. The Diisoprop3 ^r lbenzoldihydroperoxyd can from this second extract by distilling off the solvent, optionally under reduced pressure, can be obtained.

However, not all of the above combinations of extraction and washing liquids known for countercurrent extraction are suitable, since the most important requirement to be met for the use of the solvent pair is that the distribution coefficients of the diisopropylbenzene dihydroperoxide (k _d ) or the admixtures (ftf ,) must be favorable between the polar and the non-polar solvent.

The distribution coefficient of a component of the starting material is the ratio of the concentration of this component in the extract or Raffinate phase understood at an extraction equilibrium in a single stage. Both the absolute values of the distribution coefficient and the factor k _d / k _{b are} essential. It is known that the last-mentioned value is a measure of the selectivity of a solvent pair. The more this value deviates from 1, the more selective the solvent pair acts with regard to the components or component groups of the mixture to be broken down. The values found for the distribution coefficient enable the person skilled in the art to determine the optimal extraction conditions for a specific individual case.

It has been found that the lower the alkanol content, the lower the dissolving power for the hydroperoxides, but that at the same time the selectivity with respect to the separation of diisopropylbenzene dihydro and -monohydroperoxide increases. But if the solvency for the dihydroperoxide is lower, will a higher ratio of extraction liquid to the mixture to be extracted is required. This The disadvantage can be completely or partially overcome by using a higher extraction temperature selects, which, however, is below the decomposition temperature of the hydroperoxides. The lower the If the alkanol content is, the higher is generally the temperature at which the extraction is carried out should be, provided that the ratio of extraction liquid to that to be extracted Mixture not changed. When the extraction liquid does not contain alkanol, extraction temperatures are in the range from 50 to 100 ° C., preferably in the range from 70 to 90 ° C., is expedient. At 15 to 25 ° C is the cheapest amount of alkanol in the Extraction liquid in the range of 30 to 60 percent by weight (70 to 40% water).

Despite the obvious advantages of working at room temperature, the application a higher extraction temperature and only water as extraction liquid advantageous because in this case an optimal selectivity is achieved and no alkanol is recovered must (so that alkanol losses are also avoided) and the mixture to be extracted in general when leaving the oxidation vessel itself a temperature in the range of about 70 to 90 ° C. In this case it is necessary to use a larger ratio of extraction liquid of the liquid to be extracted. Depending on the circumstances, extraction can take place at Room temperature or at an elevated temperature may be more advantageous.

The preferred alkanol is methanol. The application Selectivity obtained from ethanol-water mixtures as the extraction liquid is lower than with methanol-water mixtures. When using ethanol-water mixtures, the ethanol content is in the extraction liquid generally less than 50 percent by weight.

Since it could be expected that alcohols promote the decomposition of hydroperoxides (see Journal Organic Chemistry, 1951, pp. 113 to 127), it was surprising that practically no decomposition of the Hydroperoxides among the various embodiments of the process according to the invention applied conditions was to be determined.

The washing liquid used in the extraction is a liquid hydrocarbon. Since the continuous oxidation of diisopropylbenzene

The peroxide balance was thus the following:

41.92 millimoles

Reaction mixture

10.3 x 4.07
Aqueous layer 12.82 ■ 0.40 = 5.13 millimoles

Hydrocarbon layer

20.18 x 1.76 = 35.52 millimoles

-40.65 millimoles

Shortfall 1.27 millimoles

When this experiment is repeated, 153 g of water, 10.61 g of in-diisopropylbenzene and 10.62 g of the above-mentioned oxidation mixture were used as the starting material, a peroxide balance was established achieved which gave a 1.12 millimole excess.

Since the loss and excess found are within the experimental error limits, from the foregoing Report concluded that no decomposition of peroxide occurred during the test was.

Patent claims:

25th

1. Process for separating diisopropylbenzene dihydroperoxides from their mixtures with Diisopropylbenzene and its oxidation products by extraction with an aqueous liquid, characterized in that one

mixed extracted with two solvents that move in countercurrent to each other and only a little are soluble in one another, one of which is a neutral, aqueous liquid, which is 0 to Contains 80 percent by weight of an alkanol with a maximum of 2 carbon atoms in the molecule, and the other is a liquid hydrocarbon.

2. The method according to claim 1, characterized in that with water at 50 to 100 ° C, extracted preferably at 70 to 90 ° C, the weight ratio between the imported Water and the mixture to be extracted between 20: 1 and 5: 1, preferably between 15: 1 and 10: 1.

3. The method according to claim 1, characterized in that one is used as the aqueous liquid Mixture of methanol and water is used, which is preferably 30 to 60 percent by weight of methanol contains, wherein the extraction temperature is between 15 and 25 ° C and the weight ratio between the aqueous methanol and the mixture to be extracted in the range of 10: 1 to 1: 1, preferably from 5: 1 to 2: 1.

4. The method according to claim 1 to 3, characterized in that the hydrocarbon used is an alkane which has 5 to 7 carbon atoms in the molecule.

Considered publications:
British Patent No. 727 498.

1 sheet of drawings

® 909 769/581 3.60

Claims (1)

■ this must be supplemented, it may be advantageous to use diisopropylbenzene itself as washing liquid. But this has the disadvantage that generally more diisopropylbenzene would be required as washing liquid than to supplement the starting material is required, so that it would still be necessary to use part of this connection z. B. separated by partial distillation of the raffinate phase, which in turn results from the application advantage gained by diisopropylbenzene is lost. One disadvantage of using diisopropylbenzene and also of aromatic hydrocarbons is the low selectivity. Aliphatic (including the cycloaliphatic), especially saturated hydrocarbons are therefore preferred used. In order to achieve a clean breakdown of the dihydroperoxide-free raffinate during the distillation, the cycloalkanes with 5 to 7 carbon atoms in the molecule are particularly preferred. When only water is used as the extraction liquid, the preferred weight ratio is between the supplied water and the mixture to be extracted in the range from 20: 1 to 5: 1 and in particular from 15: 1 to 10: 1. When methanol-water mixtures with a concentration between 30 and 60 percent by weight of methanol as extraction liquid are used at a temperature in the range of 15 to 25 ° C, the weight ratio is between the fed aqueous Methanol and the mixture to be extracted are preferably in the range from 10: 1 to 1: 1 and in particular from 5: 1 to 2: 1. The amount of washing liquid used is so large that it is about the same order of magnitude as the amount of the starting peroxide mixture supplied, preferably in a ratio of washing liquid to the starting peroxide mixture fed in in the range from 0.5: 1 to 2: 1. The method according to the invention is of particular importance, e.g. B. in terms of manufacture of resorcinol, for the continuous separation of m-diisopropylbenzene dihydroperoxide from organic ones Peroxide mixtures obtained by the hydration of m-diisopropylbenzene with an oxygen-containing one Gas had been obtained. example 1 A reaction mixture obtained by hydroperoxidizing m-diisopropylbenzene, the 52.5. Weight percent m-diisopropylbenzene monohydroperoxide and 15.6 percent by weight of m-diisopropylbenzene dihydroperoxide was with a mixture of methanol and water (weight ratio 50:50) in batches at 20 ° C using separating funnels in seven theoretical stages using hexane as washing liquid. The amounts fed in per batch were: 20 g of hexane, 30 g of the methanol-water mixture and 10 g of the oxidation mixture. The two solvents were countercurrently at the ends of the extractor and introduced the reaction mixture in their center. After the steady state was reached, it was found that the amount of mono- and dihydroperoxide of m-diisopropylbenzene in the final extract consisted of 92.5 percent by weight of diisopropylbenzene dihydroperoxide and 7.5 percent by weight of diisopropylbenzene monohydroperoxide. It was also found that 84 percent by weight of the dihydroperoxide obtained in the reaction product had been extracted and that 99 percent by weight of the monohydroperoxide originally present had not been extracted.
From this it can be calculated that the ratio of the distribution coefficients of diisopropylbenzene dihydro- and monohydroperoxide was about 5: 1. Example 2 30 parts by weight of an aqueous solution containing 50 percent by weight of methanol and at 20 ° C with η-hexane had been saturated, were per minute at 20 ° C in the first stage, so in the upper part of a Extraction device with rotating disks, which is above the inlet opening for the loading contained six theoretical extraction stages and five theoretical washing stages under the inlet opening, initiated. There were 18 parts by weight of n-hexane ao (saturated with the aqueous methanol) per minute in the tenth stage, i.e. in the lower part of the Extraction device, and 10 parts by weight of the reaction mixture as used in Example 1 had been introduced into the sixth stage of the same. The distillation of the extract obtained from the extractor in an amount of 31.9 parts by weight per minute gave a yield of 1.65 parts by weight under reduced pressure per minute of an m-diisopropylbenzene dihydroperoxide of 93.1% purity. The washing liquid extract (26.1 parts by weight per minute) was obtained by distilling under reduced pressure from Freed washing liquid. The distillation residue obtained was returned to the oxidation vessel. 98 percent by weight of the amount of diisopropylbenzene dihydroperoxide contained in the oxidation mixture was obtained extracted, and only about 1 percent by weight of that present in the oxidation mixture Monohydroperoxide was carried along with the extraction. Example 3 a) 10 parts by weight of water, 1 part by weight of m-diisopropylbenzene as washing liquid and 1 part by weight of the oxidation mixture according to Example 1 were shaken at 80 ° C. until phase equilibrium had been achieved. The distribution coefficients at this temperature were determined by infrared analysis of the obtained components. For the diisopropylbenzene dihydroperoxide this coefficient was about 0.14, for the monohydroperoxide it was about 0.01. The value for k _d lk _b was about 14. b) 153 g of water, 10.39 g of m-diisopropylbenzene and 10.30 g of the oxidation mixture mentioned under a) were shaken together at 80 ° C. for 3 hours. The amount of the obtained extract liquid was 153.51 g, the amount of hydrocarbon wash liquid was 20.18 g. The peroxide number of the hydrocarbon extract (determined by iodometric titration) was 176. The aqueous extract was washed three times with 6 g of m-diisopropylbenzene. After it was determined that the hydrocarbon extract from the third wash was not per showed more oxide number, the hydrocarbon extracts from the first and second extraction united. The amount of the hydrocarbon extract thus obtained was 12.82 g. It had a peroxide number of 40. The peroxide number of the reaction mixture was 407.