FI56816C - FOERFARANDE FOER REGENERERING AV EN DEGRADERAD ARBETSLOESNING VID FRAMSTAELLNING AV VAETESUPEROXID ENLIGT ANTRAKINONFOERFARANDE - Google Patents

Description

1 “τ \ ΓβΙ m, ADVERTISING PUBLICATION

LBJ (11) UTLAGG N I NGSSKRI FT 56816 1¾¾ C (45) Patent granted1? tty ΙΟ J! 1930 ifiri2f Patent oeddelat ^ '(51) Kv.lk. * / Lnt.CI.' G 01 B 15/025 SUOMI - FINLAND (21) P »t« nttih »k« mu * - Pttentantttknlng 670/71 (22) Hakemljpllvi - An * öknlng * d »g 08.03.71

^ ^ (23) AlkupUvi - Glltighetsdag qQ

(41) Become Public - Bllvlt offtntlig Qg yg

Patent and Registration Office .... ...... " , .......

1 (44) Date of delivery and date | Ullal * un pvm.—

Patents and registration Anstfkan utlagd och utl.ikrlftan publlcerad 31.12.79 (32) (33) (31) Pyydetty pruoiteus — Begird prloritet 2.8.08.70

Japan-Japan (JP) Sho ^ 5-7189 ^ (71) Mitsubishi Gas Chemical Company, Inc., no. 5 ~ 2, 2-chome Marunouchi,

Chiyoda-ku, Tokyo, Japan-Japan (JP) (72) Hiroshi Shin, Mie-ken, Junichiro Sugano, Mie-ken, Tadashi Yoshii,

Tokyo, Kichiro Iwamcto, Mie-ken, Yasuhisa Kuriyama, Mie-ken,

Minoru Kakuda, Mie-ken, Japan-Japan (JP) (7 ^) Oy Kolster Ab (5 ^) Method for the regeneration of a degraded working solution in the preparation of hydrogen peroxide using the anthraquinone method - Förfarande för Regeneration av en degraderad arbetslösning vid framställning av vätesuper-ox en antrakinonförfarande

The invention relates to a process for regenerating a degraded working solution in the production of hydrogen peroxide using the anthraquinone process by dehydration by contacting the working solution with gaseous olefins using a supported platinum group metal at a temperature above 130 ° C, whereby tetrahydroanthraquinone is dehydrated.

In the preparation of hydrogen peroxide by an auto-oxidation process, a working solution containing potent anthraquinones such as cardiac alkylated anthraquinone or cardiac alkylated tetrahydroanthraquinone (corresponding formulas I and V below) is usually used.

For example, as shown in the following equation, the effective anthraquinones are catalytically hydrogenated to the corresponding anthrahydroquinones (Formulas II and III), and the anthrahydroquinones formed are oxidized with a molecular oxygen-containing gas to regenerate the anthraquinones and the hydrogen peroxide formed is extracted with water.

2 i 55816 i γΥυrR - - (I) - o,: + h2 I + h2 * -i * i

OH HOH 0H

r * yVvR QQfTR rJiV> R

^ T xf λ "Oli s" (III) • 0H (II) 0 (iv); + C2 +02 £ ^ 1 'o n H2O2 11202 _ Is

f Y YY ", L; · Λ. i! .Y

0 Γ +, 2 ° ίν) 1 (I) * '’3 56816

When the hydrogenation and oxidation reaction of the efficient anthraquinone is repeated, degraded substances are formed as a result of side reactions which do not lead to the conversion between quinone and hydroquinone even if the hydrogenation and oxidation reaction is carried out under normal conditions.

Degraded substances include oxyanthrone (Formula IV) and other degraded substances that are unusually reduced products of anthraquinone and are termed "ineffective anthraquinone"; because they do not contribute to the formation of hydrogen peroxide.

Although the amount of ineffective anthraquinone formed per cycle is very small, it accumulates progressively as the same working solution is recirculated over a long period of time. In this case, it not only causes various disadvantages, but also results in a reduction in the effective concentration of anthraquinone in the working solution. Ineffective anthraquinone is easily converted to still other degraded substances which, however, cannot be regenerated to anthraquinone during recirculation or even if the working solution is subjected to a vigorous regeneration treatment, resulting in the loss of effective anthraquinone.

Therefore, some suggestions have been made to regenerate the working solution.

It has been reported in the literature that the working solution can be treated with or without an oxidizing agent in the presence of an ion exchange resin or base used as a catalyst. However, in the case where no oxidizing agent is used, the treatment carried out using the catalyst causes a reduction in the regeneration efficiency, i. the conversion of ineffective anthraquinone to non-regenerable, degraded substances increases. This may be due to insufficient dehydration in the regeneration treatment. When the dehydration is carried out using an oxidizing agent, for example oxide or molecular oxygen, the service life of the catalyst used for regeneration is considerably shortened as a result of the formation of degraded substances due to side reactions.

It has now been found that a degraded anthraquinone, such as oxy-anthrone, can be most effectively regenerated to anthraquinone by minimizing the formation of non-regenerable degraded substances by using a weak, hydrogen-binding agent.

The invention is characterized in that the working solution also contained antrakinonijohdannainen ineffective, mainly oksiantrakinonia regenerated by keeping dehydrauslämpötila at the beginning of at least half an hour at 70-120 ° C.

56816

The catalyst suitable for the present invention consists of a platinum group metal such as platinum, palladium, ruthenium or a mixture thereof on a support, and the catalyst may also contain another metal such as nickel, silver or copper. A suitable support for the catalyst is an alkaline earth metal oxide such as calcium oxide or magnesium oxide, alumina or a compound consisting essentially of the above-mentioned oxide, i. CaQ.A ^ Og, MgO.Al ^ g, MgO.SiQ2 or the like. As the supported catalyst of the present invention, there can be mentioned Pt-A 2 O 2, Pd-A 2 O 2 or Pd-MgO. Al 2 O 2.

A catalyst, for example Pd-AlO 2, can be prepared as follows: Active alumina with a particle size of 100-200 mesh is suspended in water; an aqueous solution of Na 2 PdCl 2 is added to the suspension and, with stirring, the palladium salt is absorbed into the carrier; an aqueous solution of formaldehyde is added to the solution, and the pH of the solution is adjusted to 9-10 by adding an aqueous solution of NaOH; the solution is heated with stirring and Pd-Al 2 O 4 is formed due to reduction of the palladium salt; the Pd-Al 2 O 3 thus formed is washed with deionized water and then dried below 100 ° C.

In the process of the present invention, the main reaction in which the ineffective anthraquinone is converted to the effective anthraquinone is dehydration and the olefin acts as a scavenger for the hydrogen released from the ineffective anthraquinone. In view of the olefin used as the hydrogen-binding agent, it is preferable that its hydrogenated product be gaseous at the reaction temperature because the gaseous product can be easily removed from the reaction system and the reaction can be carried out successfully. In particular, ethylene and propylene are preferred hydrogen scavengers.

The working solution is prepared by dissolving alkyl anthraquinone and alkyl tetrahydroanthraquinone in a solution mixture consisting of a higher alcohol and an alkylated aromatic hydrocarbon.

After continuous use of the working solution for a long time, it is found that it contains a considerable amount of ineffective anthraquinone, which has been formed due to the unusual reduction of effective anthraquinone. The catalyst is added to a working solution containing an ineffective anthraquinone and the working solution is contacted with olefin gas or an inert gas containing olefin gas 5 56816 at a temperature below 150 ° C * The working solution can be contacted with gas using stirrer vessels * into which the gas is sucked in or * or a tower * into which the gas is passed through a perforated plate or diffusion nozzle. In the above treatment, the ineffective anthraquinone *, which is an abnormally reduced substance *, dehydrates to the effective anthraquinone.

There is another self-oxidation process * in which only anthraquinone is used as the working medium in the recycled solution. In this process, the concentration of tetrahydroanthraquinone in the working solution is adjusted to the lowest possible amount * because tetrahydroquinone is difficult to oxidize under such mild conditions * used to oxidize anthraquinone * because the oxidation rate of tetrahydroanthraquinone is much lower than that of anthraquinone.

In order for the working solution to be recycled during oxidation under mild conditions *, it is therefore necessary for the process * that the tetrahydroanthraquinone formed in the hydrogenation of the anthraquinone is subjected to dehydration to regenerate the anthraquinone. In the case * that the dehydration rate of a working solution containing a large amount of degraded anthraquinone, such as oxyanthrone, is directly subjected to tetrahydroanthraquinone, the dehydration rate is greatly reduced.

The present process can be advantageously combined with the dehydration of tetrahydroanthraquinone * because not only the rate of dehydration is considerably increased * but also the dehydration catalyst is able to maintain high activity by first regenerating the working solution and then dehydrating the tetrahydroanthraquinone.

Example 1

The working solution was prepared by dissolving 2-amylanthraquinone in a mixture * containing 50:50 by volume of trimethylbenzene and diisobutylcarbinol * to a concentration of about 1 mol / liter. Hydrogen peroxide was prepared successively for a long time using the above-mentioned working solution in a circulating operation * comprising alternating hydrogenation of anthraquinone and oxidation of the obtained anthrahydroquinone to regenerate anthraquinone * which is recycled after extraction of the hydrogen peroxide formed with water. As can be seen from Table 1 below, the working solution obtained was found to contain 0 * 26 moles / liter of ineffective anthraquinone. To one liter of the working solution was added 50 g of Pd-MgO.Al_0_ catalyst containing 2 5% palladium metal prepared by the method described above * and the working solution was heated at 90 ° C for 50 minutes with stirring and introducing ethylene gas. As a result of the treatment, the ineffective anthraquinone was regenerated to 2-amylanthraquinone * as shown in Table 1. The numbers in Table 1 indicate the concentrations (mol / liter) of the components contained in the working solution. Dehydration of tetrahydroanthraquinone in the regeneration treatment is hardly noticeable.

6

S δ 8 1 S

table 1

Powerful anthraquinones

Anthraquinone Tetrahydroanthraquinone

In manufacture 1.00 0.00

Before regeneration 0.63 0.09

After hegeneration 0.77 0.09

Reference Example 1) The working solution regenerated in Example 1 was reacted by introducing ethylene gas, while stirring constantly, in the presence of the same catalyst as used in Example 1, at a concentration of 100 g / liter at 160 ° C and a treatment time of about} 0 minutes. Temperatures as high as 160 ° C had to be used to dehydrate tetrahydroquinone to anthraquinone.

2) The degraded working solution, which had not yet undergone the regeneration treatment according to Example 1, was reacted to dehydrate tetrahydroanthraquinone under the same conditions as in 1 above.

Table 2 shows the concentrations of tetrahydroanthraquinone in the working solution (mol / liter) discussed in 1) and 2) above. The amount of anthraquinone regenerated upon dehydration of tetrahydroanthraquinone in the working solution treated as described in Example 1 was 3 times higher than in the working solution not yet treated.

Table 2

Before hydrogenation After dehydration Concentration difference 1) 0.09 0.06 0.03 2) 0.09 0.08 0.01

Example 2

The working solution was prepared by dissolving 2-butylanthraquinone in a mixture containing 30:30 by volume of tetramethylhentene and diisobutylcarbinol to a concentration of about 0.6 mol / liter.

The working solution was recycled as described in Example 1 to obtain a degraded working solution which did not contain a large amount of ineffective anthraquinone.

A one-liter sample of the degraded working solution was stirred while introducing propylene containing 30 volumes of propane-5 5,8816 at the same time as 0 g of Pd.Pt-AlgO 2 catalyst was present at 90 ° C for 40 minutes. The catalyst was prepared by causing the palladium and platinum salts to be absorbed into AlO 2 to a concentration corresponding to 0.9 wt% metal 2 palladium and 0.1 wt% metal platinum, followed by reduction of the salts with formaldehyde in an alkaline solution.

The concentrations of the components in the working solution were determined. The results are shown in Table 3 ·

Table 3

Effective anthraquinone

Anthraquinone Tetrahydroanthraquinone

In the manufacture 0.60 0.00

Before regeneration 0.41 0.09

After regeneration 0.51 0.09

Example 3

The working solution was prepared by dissolving 2-ethylanthraquinone and 2-ethyl-tetrahydroanthraquinone at concentrations of 0.3 mol / liter and 0.3 mol / liter, respectively, in a mixture containing 50:50 by volume of tetramethylbenzene and di-iobutylcarbol. The working solution was recycled as described in Example 1 to obtain a degraded working solution.

A 1 liter sample of the degraded working solution was stirred while introducing butylene in the presence of a Pd-CaO.Al 2 O 2 catalyst at 100 ° C for 45 minutes. The catalyst was prepared by causing the palladium salt to be absorbed into CaO AlgO 2 to a concentration of 1 wt% of palladium metal, followed by reduction of the salt with formaldehyde in an alkaline solution. The concentrations of the components in the working solution were determined. The results are shown in Table 4 *

Table 4

Effective anthraquinone

Anthraquinone Tetrahydroanthraquinone

In the manufacture of 0.30 0.30

Before regeneration 0.19 0.31

After regeneration 0.24 0.31

Examples 4 ”5

The working solution was prepared by dissolving 2-amylanthraquinone in a mixture containing, by volume, 50 to 50 trimethylbenzene and diisobutylcarbinol to a concentration of about 1.20 mol / liter.

8 56816

The working solution was recycled as described in Example 1 to obtain a degraded working solution.

Two 1 liter samples of degraded working solution were stirred separately at 90 ° C for one hour while ethylene was introduced, and in each case 50 g of catalyst were present, in one case Pt-MgO.Al 2 O 2 and in the other case Hu- MgO.AlgOj. The concentrations of the components contained in each working solution were determined. The results are shown in Table 5 ·

Table 5

Effective anthraquinone

Catalyst

Anthraquinone Tetrahydroanthraquinone

In manufacture 1.20 0.00

Before regeneration 0.90 0.07

Ex.4 After Eegeneration Pt-MgO.AlgOj 1.10 0.07 "5" Eu-MgO.AlgOj 1.10 0.07