DE1802003A1 - Process for the recovery of non-aqueous hydrogen peroxide solutions - Google Patents

Description

! 802003

GERMAN GOLD AND SILVER SCIIEIDEANSTALT FORMERLY ROESSLER Frankfurt am Main, ¥ eissfrauenstrasse 9

Process for obtaining non-aqueous hydrogen peroxide solutions

The invention relates to a method for obtaining non-aqueous hydrogen peroxide solutions.

The preparation of hydrogen peroxide according to the anthraquinone process uses a solution (here called working solution for short) of one or more alkali anthraquinones in a high-boiling solvent that is resistant to oxygen and hydrogen peroxide. As alkali anthraquinones, for. B. 2-ethyl-, 2-but} '! -, 2-isopropyl-, 2-amyl-anthraquinone and their partially hydrogenated derivatives are used. The solvents used are inter alia, individually or in a mixture, alkylbenzenes, paraffins, higher alcohols, tetralin, dimethylnaphthalene and esters such as methylcyclohexylacetet and trioctylphosphate.

The working solution is Ilydrierkatalysatoren such. B. Palladium black, Palladium carrier contact or Raney nickel hydrogenated, a more or less large part of the anthraquinones being converted into the corresponding hydroquinones. After the hydrogenation contact has been separated off the working solution containing hydroquinones becomes more enriched in the oxidation stage with air, oxygen or oxygen Fumigated air. The anthrahydroquinone is oxidized again to anthraquinone, with hydrogen peroxide as a by-product in the solution arises.

In the extraction stage usually following the oxidation the . .issstoffperoxid extracted with Wassor and is then as aqueous solution.

After drying, the working solution is returned to the hydrogenation stage smuggled in, and the cycle begins again. At different Tunnels in the circuit can have regeneration or purification stages be switched on in order to avoid disruptive degradation products that

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stand, regenerate or remove.

From the aqueous solutions obtained by extraction must the hydrogen peroxide, if it is in non-aqueous solution, e.g. to be used for oxidation, be converted into an organic solvent. These are cumbersome and expensive tow distillations necessary to remove the water.

The invention is therefore based on the object of finding a method with which, while avoiding the disadvantages of the known Process for immediately preparing solutions of hydrogen peroxide in organic solvents.

According to the invention, this object is achieved by a method, which consists in the fact that one consists of the hydrogen peroxide containing Working solutions involved in hydrogen peroxide production obtained by the anthraquinone process after the oxidation stage, with the aid of a stripping distillation under reduced pressure and using vapors of organic solvents as a stripping agent »separates hydrogen peroxide and after condensation as a non-aqueous solution in the one for stripping used solvent wins, possibly at the same time separated parts of the working solution in a phase separation vessel separates and returns it to the cycle. In contrast to the known method of working, one obtains according to this Process immediately solutions of hydrogen peroxide in the organic solvents used for stripping.

The stripping distillation is preferably carried out at pressures between 5 and 60 Torr and at temperatures between 30 and 110 ° C carried out.

The vapors of such sub- ^ are best suited for stripping punch, which dissolve hydrogen peroxide and under the - "" " driving conditions are not attacked. To these * "©

ο Substances count, depending on the intended use, for example carboxylic acids such as formic acid, acetic acid, propionic acid or esters such as ethyl acetate,

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Propyl acetate, butyl acetate. But also alcohols such as propanol, butanol, Cyclohexanol have proven to be very suitable.

If one intends, for example, to further process the organic hydrogen Poroxide solution based on peracids is used as a stripping agent the corresponding base acid, e.g. B. in the production of peracetic acid, acetic acid.

However, mixtures of carboxylic acids and esters or of alcohols and esters can also be used for stripping. G

In many cases, when stripping, parts can be omitted the working solution by using a low reflux in the stripping apparatus, which has a reflux ratio (R: E) of 1.5 up to 0.5 must be avoided.

Possibly passed over during stripping, with the hydrogen peroxide-containing Stripping agents Immiscible proportions of the working solution can be removed from the hydrogen peroxide-containing stripping agent by phase separation isolate without difficulty and return to the circulating working solution. This is e.g. D. the case when using acetic acid as a stripping agent. Is the working solution z. B. from alkyl anthraquinone, trloctyl phosphate and I. Alkylbenzenes do the same with acetic acid and hydrogen peroxide Alkylbenzene over. This separates in the template from the solution of hydrogen peroxide in acetic acid, so that at a Execution of the template as a phase separation vessel, simple insulation of the alkylbenzenes is possible. The advantage here is that

Q alkylbenzene contains at most small amounts of hydrogen peroxide.

- »The invention is based on an exemplary embodiment and the attached

> n. Lowing drawing further explained below. ° example

On the head 11 of a stripping column 1 was a preheated to 70 C, Solution originating from the circulation of the anti-urachinone process

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of 9 »3 g of hydrogen peroxide in one liter of a mixture 272 ml of trioctyl phosphate, 633 ml of tetramethylbenzenes and 120 g Abandoned ethyl anthraquinone. The working solution flows over the Column and leaves it in the lowest part at 12 via a Liquid seal.

In the lower part of the column at 13, acetic acid vapor superheated to 100 ° C. is blown into the column operated under a pressure of 18 torr. At the top of the column, the acetic acid stripping vapor leaves the column together with hydrogen peroxide and a small amount of tetramethylbenzene, is condensed in the cooler 2 and separated in the separator 3. 9-8% of the hydrogen peroxide applied to the column 1 is found in the separator 3, the remainder in the working solution running off at the bottom of the column at 12. At 13, 80 g of acetic acid vapor are blown in per liter of working solution, of which 53 S pass with the distillate. The rest remains in the column effluent. In the separator 3, a solution of 1 ^, 7 weight falls.% H ₂ O ₃ in acetic acid. At the same time, 28 g of tetramethylbenzene separate per liter of working solution used. \ By heating the sump, the amount of acetic acid present in the outlet 12 can be significantly reduced or removed at all.

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Claims (1)

- 5 - ■■■ '■ ■ ". ■■■. Pa t θ η * ta η α ρ r Ü ο he y Process for the production of non-aqueous hydrogen peroxide solutions, This is characterized by the fact that from the hydrogen peroxide-containing working solutions that are used in the production of hydrogen peroxide obtained by the anthraquinone process after the oxidation stage, with the aid of a stripping distillation under reduced pressure and using vapors of organic solvents as stripping agents, hydrogen peroxide separated and recovered after condensation as a non-aqueous solution in the solvent used for the stripping, optionally at the same time separated parts of the working solution are separated in a phase separation vessel and returned to the cycle » 2.Verfahren according to claim 1, characterized in that the Stripping distillation at pressures between 5 and 60 Torr and at temperatures between 30 and 110 C is carried out. 3. The method according to claims 1 or 2, characterized in that that for stripping fumes of hydrogen peroxide solvent, among the Process conditions of largely chemically stable solvents are used. k. The method according to claim 3, characterized in that the strip pen carboxylic acids, such as. B. formic acid, acetic acid, propionic acid or esters, such as. B. ethyl acetate, propyl acetate ,. Butyl acetate or alcohols, such as. B. propanol, butanol, cyclohexanol, can be used. 5. The method according to claims 1 to k, characterized in that mixtures of carboxylic acids and esters or of alcohols and esters are used for stripping. 0098 17/1609 6. The method according to claims 1 to 5t, characterized in that when stripping, the passing over of fractions of the working solution by applying a low reflux in the stripping apparatus, which preferably corresponds to a reflux ratio (Π: Ε) of 1.5 to 0.5 , avoids. 7. The method according to claims 1 to 6, characterized in that during the stripping, if necessary, parts of the working solution which are not miscible with the hydrogen peroxide-containing stripping agent are isolated from the hydrogen peroxide-containing stripping agent by phase separation and are returned to the working solution in the circuit. September 10, 1968
Dr.Kr/Ta 009817/1609