FI61299C - REGENERERINGSFOERFARANDE FOER KINONFOERBINDNINGAR - Google Patents

Description

Rd3CT ΓβΙ mv ANNOUNCED * PUBLICATION, 10QQ

JSTa l J (11) UTLÄOCNINOSSKRIPT 6Ί 2 99 q & Qjp C Patent granted on 12 07 1902

Patent meddelat (51) Kv.ikV.ci.3 c 01 B 15/025, c 07 c 50/00 FINLAND —FINLAND (21) N ** ntt «» l »nw« - teuntaMBkitlng 3538/72 (22) Hak «Ml« pllv · - Anrtkrrfngrtug lL.12.72 (23) AlkupiWl-GlMghatrtag lU.12.72 (41) Tullut julklMlul - Bllvlt offantllg 21.06.7 3

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Patant- och raglftaratyralaan '' Anujkan utiagd och utUkrttm publicmd 31.03.82 (32) (33) (31) Pyyd * «r« η © ΙΙι · μ — Begirt prtorHet 20.12.71 20.12.71 England-England (GB) 59029 / 71 59030/71 Proven-Styrkt (71) Laporte Industries Limited, Hanover House, lU Hanover Square, London, WI, England-England (GB) (72) William Reid Logan, Kingsley, Cheshire, Alan Rippon, Liverpool,

The present invention relates to a process for the regeneration of a working solution used in the batchwise preparation of hydrogen peroxide with useful quinone compounds. alkaline activated alumina, alkali metal aluminosilicate, alkaline activated alumina, alkaline earth metal oxide or hydroxide, basic ion exchange resin or aqueous alkali metal hydroxide.

Useful quinone compounds that can be used in such a cyclic process include, for example, anthraquinone compounds and naphthaquinone compounds such as 2-ethylanthraquinone, 2-amylanthraquinone, 2-t-butylanthraquinone, 2-methyl-3-n-butylnaphthoquinone, 2,3- diethylnaphthoquinone or ring-hydrogenated derivatives of such anthraquinone compounds which, when the cyclic process is carried out for a longer time, form e.g. 2-ethyl-tetrahydroanthraquinone.

A frequently used solvent system comprises a mixture of a solvent, namely a solvent for quinone compounds and a solvent for quinol compounds.

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Solvents for quinone compounds are usually aromatic hydrocarbons or mixtures of such hydrocarbons together with high boiling aliphatic hydrocarbons. We prefer to use a mixture of hydrocarbons obtained from a petroleum fraction having a boiling point in the range of 145 to 210 ° C and obtained commercially from I.C.I. (England) under the trade name "AROMASOL". Alternative solvents are aryl compounds such as xylene or alkylaryl compounds such as dimethylnaphthalene or diphenylmethane.

Solvents for quinol compounds are usually esters, aliphatic alcohols or ketones. We prefer to use esters of cyclohexyl alcohol with a short chain aliphatic acid, especially methyl cyclohexyl acetate, which can be obtained commercially from Laporte Industrie Limited (England) under the tradename "SEXTA ^ E". Alternatively, the solvents may be selected from phosphate esters, alcohols such as octanol or diisobutylcarbinol, ketones such as acetophenone or diisobutyl ketone, and ethers.

The continuous use of the cyclic process of hydrogen peroxide results in a reduction in the power of the working solution and the formation of a complex mixture of decomposition products which cannot take part in the production of hydrogen peroxide. Some of these degradation products are derived from the useful quinone content of the working solution. One such class of degradation products has been isolated and may be termed quinone epoxide. The main epoxide resulting from the decomposition of 2-ethylanthraquinone in the cyclic hydrogen peroxide production process is 2-ethyltetrahydroanthraquinone epoxide of the formula

H 0 H H

H 0 H H

To date, methods for regenerating useful quinones from quinone epoxides and other methods for regenerating useful quinones from some of these other degradation compounds have been proposed.

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The process according to the invention is characterized in that the regeneration process comprises a combination of two treatments, one in which the working solution is in an oxidized state and the other in a partially, (preferably up to about 50%) reduced state.

The regenerating agent may be suitably solid or liquid. In particular, the solid regenerating agent is suitably selected from the group consisting of alkali-reactive agents, alkali metal aluminosilicates (especially sodium aluminosilicates), activated alumina, alkaline earth metal hydroxides and oxides, and base-exchanged ion exchangers, the alkalinity of which can generally be expressed to be about 5%. ) to sodium hydroxide, and non-alkaline reactants such as non-alkaline activated alumina.

When the working solution is treated in either a reduced or oxidized state with two or more solid regenerants, a bed with layers of different substances can be used.

The liquid regenerating agent may conveniently be an aqueous alkali metal hydroxide solution such as aqueous sodium hydroxide.

In particularly preferred embodiments, in at least one treatment, the regenerating agent is activated alumina, preferably non-alkaline alumina, obtained under the tradename "AC ^ AL" from Laporte Industrie Limited.

In some embodiments, the combination comprises both a change in the degree of oxidation of the working solution and the use of at least two regenerating agents that differ significantly in their properties, such as one agent, e.g. activated alumina, in a reduced solution and another agent, e.g. aqueous sodium hydroxide, in an oxidized solution.

Working solutions containing significant amounts of degradation products containing anthraquinone epoxides are particularly suitable for the treatment of the present invention. The process according to the present invention is particularly suitable for the treatment of decomposed working solutions resulting from the continuous use of a batch process which uses a working solution initially containing 2-ethylanthraquinone dissolved in a mixture of "AROMASOL" and "SEXTAATE".

The process according to the present invention is suitably carried out by taping the working solution or steps obtained from the cyclic production process of hydrogen peroxide, e.g. in each section 5-15% of the total volume of the working solution is treated. In this case, the single tap can be treated sequentially in different oxidation states, whereby the change in working solution state between treatments is carried out by oxidation with air or hydrogenation, whichever is the case, but preferably at least two side effluents are used in combination, one using oxidized and the other reduced.

Each treatment with a solid can be performed by contacting the decomposed working solution with a layer of solid regenerant at any temperature from ambient temperatures up to the boiling point of the solvent system, and preferably at a temperature of RO to 165 ° C. Generally speaking, the higher the temperature, the higher the regeneration rate. The amount of regenerating agent used is not critical. When using continuous treatment methods, the layer of regenerant should be of a suitable size to provide sufficient contact time for the desired degree of regeneration, e.g. 0.2 to 5.0%, preferably 1-2 by weight * of the total working solution can form a layer of sufficient size. In one case, it may be advisable to use different contact times for different treatments - e.g. using a longer contact time, e.g. double, for the treatment of oxidized working solutions than for the treatment of reduced working solutions. When batch treatments are used, it is suitable to use about 5-15% by weight based on the working solution to be treated.

Each treatment with a liquid substance should be carried out by mixing the substance with a thoroughly decomposed working solution at a temperature of up to about 60 ° C when the easily saponifiable ester forms part of the working solution, or up to about 140 ° C if difficult to use. saponifiable barrier thighs. Suitable amounts of substance are about 0.1 to 1% by weight, based on the amount of working solution to be treated. A suitable treatment time is about 10 to 15 minutes at 60 ° C when about 0.5% by weight of sodium hydroxide dissolved in water is used. In general, prolonging the contact time of the reneqeroin with the working solution leads asymptotically to near-maximum regeneration.

When the treatment of the reduced working solution is to be carried out, either the partially reduced working solution from the hydrogenation step of the batch process of hydrogen peroxide is treated, or alternatively such partially reduced solution can be further reduced or even the oxidized working solution can be reduced after removing the hydrogen peroxide from the batch process. In any case, the treatment according to the present method is preferably carried out in the absence of oxidizing gas.

The time each solution passes through the bed can be varied to maximize regeneration. Thus, these periods may be the same, e.g. 3 days, or preferably the treatment time of the reduced working solution may be several times the treatment time of the oxidized working solutions - such as a week - ten days in the reduced state and about 3 days in the oxidized state.

It is believed that in the treatment of reduced working solutions, quinone compounds are substantially regenerated only from quinone epoxides, while in the treatment of oxidized working solutions, useful quinone compounds are regenerated from quinone epoxides more slowly than before, but also from other quinone decomposition products.

Some specific embodiments of the present invention are described more fully below, but by way of example only. j t

Examples 1, 2, 5, 8 and 9 are in accordance with the invention. Examples 3, 4, 6, 7 and 10 are included for comparison only. 1 6 61299

Example 1

The working solution used in Example 1 was recovered from the batch process of hydrogen peroxide and contained 2-ethylanthraquinone 54 g / l tetrahydroethylanthraquinone 52 g / l quinone decomposition products 137 g / l (17 q / l were anthraquinone epoxides) methylcyclohexylacetate / "AROMASOL" % (v / v) solvent system.

The total potentiometric acidity of the solution was 17.5 meq / l·

In the example, 250 ml of the working solution was heated at 140 ° C together with 50 g of regenerant for 2 hours with stirring and using a nitrogen purge. A water-cooled concentrator was used to prevent solvent loss due to evaporation. The working solution was then filtered from the regenerating agent and analyzed. The second treatment step was performed in the same manner using a new dose of regenerating agent and the filtered and treated working solution from the treatment of the first step. When the reduced working solution was treated, it was obtained by reducing the oxidized form to the working solution immediately before the treatment by performing a reduction of up to 50% of the theoretical hydrogenation of the quinone content of the working solution. The regenerating agent used was activated alumina to give an aqueous solution containing 100 g / l of alumina and having a pH of 6.8. This alumina is sold by Laporte Industries Limited under the trade name ACTAL.

The regenerant obtained was measured as follows. The following factors were determined analytically using standard polarographic techniques.

i i

Total dry matter in working solution before treatment * TS *

Total dry matter in working solution after treatment * TSf

Quinone concentration before treatment = Qi

Quinone concentration after treatment «Qf j ί i 61299

The factors are placed in the expression

Qf (TSi / TSf) - Qi% TRx --- X 100 TSi - Qi TRj is the total recovery achieved.

The% TR2 for the second stage is calculated as above, but expressed as a percentage of the regeneration of the first stage.

The results of the example are summarized in the following Table I

Table I

_1. käsittely_2. reading_

For example, the solution% TR1 regene- The solution% TR2 regene- o_status_reduction_status_reduction_ 1_reduced_8.0_oxidized_65.0_ According to the present invention, a very good second stage regeneration is achieved, as can be seen from the example.

Example 2

The working solution and treatment method used in Example 2 were the same as described in Example 1. The regenerants used were synthetic sodium aluminosilicate containing a small amount of absorbed base and is known under the trade name "DOUCIL", and activated alumina known as the trade name "ACTAL".

The degree of regeneration achieved was measured as in Example 1.

The results are summarized in Table il.

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Table II

_1. käsittely__2. reading_

Eg Regene- Solution-% TRI regener- %- Regene-% * rR2 regen: no rotation-inducing rotation_substance_status_nose_status substance _ 2 ACTAL reduced- 8.0 oxygen- DOUCIL Q2.4 _tetty_tettu__

Examples 3-8

The working solution treated in Examples 3-8 was used in a cyclic process for the preparation of hydrogen peroxide and contained 2-ethylanthraquinone 95 g / l 2-tetrahydroethylanthraquinone anthraquinone epoxides 14 g / l other decomposition products 103 g / l

In each treatment, 1 L of the working solution was kept at 140 ° C for 2 hours together with 200 g of regenerating agent with mechanical stirring and under a nitrogen atmosphere. A water-cooled condenser was used to prevent evaporation loss of the solvent. The second treatment was performed using a new sample of regenerant. Reduced working solutions were obtained by reducing the oxidizable form in a non-oxidizing atmosphere to 50% of the theoretical maximum.

The concentration of anthraquinone epoxide was measured using standard polarographic techniques and the percentage of epoxide removed was calculated using the expression

Amount of epoxy removed not - Ef (TS | - TSf) = ---- x 100%

No where Ei and Ef are the epoxide concentration before and after treatment, respectively.

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Table III

Eg Regeneration Treatment Removed epoxy; o_aine_1_2_id,% _ 3 ACTAL reduced reduced 70 4 "oxidized oxidized 71

5 "oxidized reduced RO

6 DOUCIL reduced reduced 58 7 "oxidized oxidized 57 8 _" _ oxidized reduced_Tl_

Examples 9 and 10

The working solution and treatment method used in Examples 9 and 10 were the same as described in Examples 3-8. The initial acidity of the working solution was 13.6 meq / eq (milliequivalents / liter), which decreased during treatment to 2, 3 and 0.5 meq / l, respectively.

The shown regeneration of quinone allows a change in the dry matter content of the working solution.

The results are summarized in Table IV.

Table IV

Eg Substance Treatment Quinone regeneration,% 9 ACTAL oxidized reduced 19.6 10 _ "_ reduced reduced_9.3_

It can be seen that in Example 9 more quinone was regenerated than the amount of quinone epoxides initially in solution.