JPS61284591A - Production of hydrogen peroxide - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

Detailed Description of the Invention "Field of Industrial Application" The present invention relates to a method for producing hydrogen peroxide, and more specifically to a method for simultaneously producing hydrogen peroxide and a halogen or alkali metal halide by electrolysis. be.

"Conventional technology" Traditionally, organic methods such as the anthraquinone method and alcohol oxidation method, and electrolytic methods such as the ammonium persulfate method have been known as methods for producing hydrogen peroxide.Industrially, the anthraquinone method is mainly used. It is well known that this is the case. The anthraquinone method is a method in which anthraquinone is hydrogenated in an organic solvent using a catalyst such as palladium or nickel to produce anthrahydroquinone, and hydrogen peroxide is produced by autoxidation of anthrahydroquinone, which produces explosive hydrogen gas. and require expensive catalysts. Mainly, by-products such as perhydrogenated products are generated during hydrogenation (1), and the catalyst deteriorates, so a regeneration process of the working fluid and catalyst is required.

Furthermore, the process of separating the working fluid and catalyst is not easy.

On the other hand, in the ammonium persulfate method, which is an electrolytic method, ammonium sulfate is anodized to form ammonium persulfate, which is then hydrolyzed to obtain hydrogen peroxide. The anthraquinone method was an important industrial production method until it was industrialized, but it was replaced by the anthraquinone method as the scale of production expanded, as the cost of electric cuffs was high and there was little merit in scaling up. As a method for producing hydrogen peroxide using pond electrolysis, a method to obtain hydrogen peroxide by directly reducing oxygen at the cathode has been proposed, for example, in JP-A-58-21388.
As disclosed in Publication No. 5, a special electrolytic cell and special electrodes are required.

"Problems to be Solved by the Invention" An object of the present invention is to provide a method for producing hydrogen peroxide that is more economical and process-friendly than conventional organic methods or electrolytic methods. That is, it is a method for producing hydrogen peroxide that does not require hydrogen gas or expensive catalysts that are inconvenient to handle, and is economically advantageous and process-friendly compared to conventional electrolytic methods.

"Means for Solving the Problems" As a result of intensive research in order to solve the above problems, the present inventors focused on a method for producing hydrogen peroxide using electrolysis, and compared to conventional organic methods. We have discovered a method for producing hydrogen peroxide that is more economical and process-friendly than the electrolytic method.

That is, an alkali metal halide aqueous solution is supplied to an anode chamber of an electrolytic cell separated by a diaphragm into an anode chamber and a cathode chamber,
An alkaline aqueous solution is supplied to the cathode chamber in the presence of an organic compound or redox resin that has an oxygen reducing ability, and electrolysis is performed with a direct current, and the reduced form of the organic compound or redox resin that has an oxygen reducing ability and alkali metal water are mixed in the cathode chamber. This is a method for producing hydrogen peroxide, which comprises producing an oxide and bringing the reduced product into contact with oxygen to produce hydrogen peroxide.

The present invention will be explained in detail below.

The halogen or alkali metal halide salt produced in the anode reaction is a strong oxidizing agent, while what is produced at the cathode is an organic compound having oxygen reducing ability or a reduced form of a redox resin. Therefore, even though they are separated by a diaphragm, when they are manufactured in the same bath, there is a risk that they will react and the current efficiency will decrease. However, in the production method of the present invention, it has become clear that these reactions can be ignored and two useful components can be produced simultaneously in the same bath.

The electrolytic cell used in the present invention has a structure in which an anode chamber and a cathode chamber are separated by a diaphragm. Nafion 315 is the diaphragm material.
Any commercially available cation exchange membrane such as (registered trademark, manufactured by DuPont) can be used, and tight diaphragms such as A I 203 sintered body and porous PVC diaphragm can also be used.

As the alkali metal 710 genide supplied to the anode chamber, an alkali metal chloride or an alkali metal iodide can be used.

When the alkali metal halide is an alkali metal chloride, the anode material is preferably a noble metal coated electrode or a noble metal composite oxide used in common salt electrolysis, and when the alkali metal halide is an alkali metal iodide, a lead dioxide electrode is preferable. As the cathode material, graphite, lead, etc., which have a relatively large hydrogen overvoltage, can be used, but a carbon electrode such as graphite, which has a small catalytic decomposition ability of hydrogen peroxide, is preferable.

An example in which an alkali metal chloride is supplied to the anode chamber as the alkali metal halide will be described below.

The electrode reaction at the anode is chlorine generation. At this time, when an alkali metal hydroxide is supplied to the anolyte to maintain the pH at 6.5 to 7 and electrolysis is performed, alkali metal chlorate is substantially produced in the anode chamber. When the alkali metal is sodium, sodium chlorate is produced according to the stoichiometry of equation (1).

3C12+6NaOH→ NaCl0. +5NaC1+3H20... (1) When an alkali metal iodide is used as the alkali metal halide, an alkali metal iodate is generated. Further, if the electrolysis is continued under appropriate conditions, alkali metal periodate will be produced.

As the organic compound having oxygen reducing ability, quinone-based organic compounds such as anthraquinone derivatives, naphthoquinone derivatives, and hydro-\none derivatives can be used.

Ionic organic compounds are electrolyzed as they are, while nonionic organic compounds are electrolyzed in the presence of a suitable supporting electrolyte. In particular, water-soluble anthraquinone derivatives and naphthoquinone derivatives do not require a supporting electrolyte, and their reduction potential is relatively low, so they can be removed at a low electrolytic sliding voltage. for example,
0. Anthraquinone-2 in 1N-NaOH aqueous solution,
The half-wave potential of sodium 7-disulfonate is -0.53V
(vs. 5CE), and the half-wave potential of 2-chloro-3-(dimethylpropylamino)ethylamino-1,4-naphthoquinone is -0,68 (vs. 5CE).

The equilibrium potential of hydrogen generation at this time is -1,01■ (vs. 5C
E) is calculated.

H...(2) In the electrode reaction at the cathode, for example, when sodium anthraquinone-2,7-disulfonate is used as an organic compound having oxygen reducing ability, anthrahydroquinone-2, Produces sodium 7-disulfonate and sodium hydroxide.

Sodium ions migrate from the anode chamber through the diaphragm.

When the catholyte is brought into contact with oxygen, hydrogen peroxide and the original sodium anthraquinone-2,7-disulfonate are formed according to equation (3).

(3) As the redox resin, a quinone redox resin is preferable. For example, hydroquinone-formaldehyde condensation resin [V
, Verplank+et at, +J, Poly
merSci, 19, 307 (1956)] and hydroquinone lul+ 48 omotsu styrene polymer [
K, A, Kun, etal,, J, Po1y+o
er Sci, A+3+1833 (1965)], and it is well known that the reduced forms of these redox resins react with oxygen to produce hydrogen peroxide.

The former is applied or impregnated onto the surface of the graphite cathode.

The latter brings the polymer particles into contact with the cathode surface. At this time, graphite particles may be mixed in order to improve the contact between the polymer particles and the cathode surface. (4), and a reduced form of the redox resin and an alkali are generated. When the reduced form and oxygen are brought into contact with each other, hydrogen peroxide and the original oxidized form are regenerated. The oxidized form is regenerated. It is subjected to a reduction reaction in the cathode chamber.

H ...(4) Air can be substituted for the oxygen that is brought into contact with the catholyte.

When using an organic compound with oxygen reduction ability, if oxygen is blown directly into the cathode chamber, the hydrogen peroxide produced will undergo electrolytic reduction and decompose. It is desirable to manufacture and separate the After separating sodium hydroxide and hydrogen peroxide from the catholyte, the catholyte is circulated back to the cathode chamber. In addition, when a redox resin is used, it is easy to separate the product from the redox resin by separating the reductant from the catholyte, transferring it to another container, and bringing it into contact with oxygen. Hydrogen and hydrogen can be produced as separate solutions.

Methods for separating hydrogen peroxide from an aqueous solution include extraction with an organic solvent such as propyl acetate, or contacting with Ca(OH)2 and filtering it as CaO2. Also,
The alkali metal hydroxide is separated by dialysis using a -valent anion selective exchange membrane.

If the separated alkali metal hydroxide is supplied to the anode chamber and the pH of the anolyte is controlled, alkali metal chlorate can be produced according to equation (1), which is economically advantageous. At this time, the overall reaction at both poles is expressed as equation (5), which essentially means that hydrogen peroxide and alkali metal chlorate are simultaneously produced using oxygen and alkali metal chloride as raw materials. Become.

30□+MCI+6)120 →3H20□+MCIO
3+3820 (5) "Operations and Effects" As explained above, according to the method of the present invention, hydrogen peroxide and halogen or alkali metal halide can be simultaneously produced in the same electrolytic cell.

Since two useful components can be produced simultaneously in the same bath, the power consumption can be reduced compared to conventional methods even with the same electrolytic method. Furthermore, compared to the conventional anthraquinone method, it does not require hydrogen gas, which is difficult to handle, or expensive catalysts. Furthermore, if the reduction potential of the organic compound or redox resin having oxygen reducing ability is controlled at a constant level, the selectivity of the reduction reaction is good and it is possible to suppress the formation of by-products.

Furthermore, the production method of the present invention can also be applied to the synthesis of inorganic peroxides such as calcium peroxide or organic peroxides.

Hereinafter, the present invention will be explained in detail with reference to Examples.

"Example 1" An electrolytic cell was used in which both electrode chambers were separated by a cation exchange membrane Sufion 315 (registered trademark, manufactured by DuPont), and the cathode was made of graphite (S OX 100n+m). The cathode comprises a saturated calomel electrode (SCE) as a reference electrode.

The cathode chamber was charged with an electrolytic solution consisting of sodium anthraquinone-2,7-disulfonate loOg/l and NaOH 0.2N, which was degassed with nitrogen. NaC12 in the anode chamber
An electrolytic solution consisting of 00 g/I was charged. The capacity of each is 500ml.

The cathode potential is 10, 60■ (vs. 5CE), and the current density is
Electrolysis was carried out at 3 A/am2 for 3 hours. After the electrolysis was completed, the catholyte was transferred to another container and oxygen gas was blown into it for 10 minutes, and then the generated H2O2 and NaOH were quantitatively analyzed.

The cathode reaction products are H2O22.7g, NaOH6
, 4g, and the current efficiency was 95%. In addition, the catholyte was concentrated and the precipitated anthraquinone was analyzed, but no by-products were observed.

"Example 2" In the electrolytic cell used in Example 1, the cathode chamber contained 20 g/I of 2-chloro-3-(2-dimethylpropylamino)ethylamino-1,4-naphthoquinone bromide, Na
Electrolyte 500 consisting of C16g/I, NaOHO, IN
m1 was degassed with nitrogen and charged. NaC13 in the anode chamber
500 ml of electrolyte containing 0 g/l was charged.

The cathode potential is -0.80V (vs. 5CE), and the voltage is 0.1A/
cln+" for 1 hour. After electrolysis, the catholyte was transferred to a pond container and air was blown in for 10 minutes, and then the generated H2O2 and NaOH were quantified. Chlorine generated during electrolysis was separated and absorbed. , was analyzed separately.

The catholyte contains H20□ 0.03. , Na0HO007
g was produced. Current efficiency is 88%.

The anode reaction product is 0.06 g of C1□, and the current efficiency is 91%.

"Example 3" The same operation as in Example 1 was performed except that an aqueous sodium hydroxide solution was added dropwise to the anolyte using a pH stat and the pH was maintained at 6.71.

The cathode reaction product is H2022, 6g, N a OH
6.2 g, and the current efficiency was 93%. The anode reaction product is 2.7 g of NaClO2, and the current efficiency is 90
%Met.

"Example 4" The two electrode chambers are separated by a cation exchange membrane Sufion 315 (registered trademark, manufactured by DuPont), and the cathode is made of graphite (50Xb oxide-coated titanium (50X1001IIm))
An electrolytic cell consisting of Each bipolar chamber is 1o.

ml capacity, and is equipped with a liquid inlet and an outlet.

The catholyte was charged with an aqueous solution containing 100 g/l of sodium anthraquinone-2,7-disulfonate and NaOH002N, and the anode chamber was charged with an aqueous solution containing 1200 g/l of NaC. The effluent from the cathode chamber has a capacity of 100+o
210 g of Ca(OH) enters a tank of 1 liter of oxygen and comes into contact with oxygen, then enters a tank of 0+n 1 of other volumes], OO + n
The slurry is stirred and mixed. Thereafter, it was filtered and only the filtrate was recycled to the cathode chamber. The effluent from the anode chamber entered a storage tank with a capacity of 400 ml and, after removal of chlorine by air blowing, was recycled to the anode chamber. Chlorine gas was absorbed separately and quantitatively analyzed.

Both electrode solutions were each 500 ml and subjected to constant potential electrolysis for 5 hours at a sliding voltage of 3.5 . The current density was 4 A/dm''.

When CaO2 and NaOH produced in the cathode reaction were quantitatively analyzed using a conventional method, 1g of CaO2, 1g of NaOH6
, 7cH were produced, and the reaction yield was 90%. In the anodic reaction, CI □ 12.2 g and O, Ig NaCl ○
was produced, and the current efficiency of chlorine production was 92%.

"Example 5" 11 parts of hydroquinone, 33 parts of 37% formalin, and 1 part of sodium hydroxide were mixed at 100°C under nitrogen and reacted for 30 minutes. After diluting the resulting high viscosity solution by adding 30 parts of methanol, a graphite plate (2×5c[o]) was immersed for 5 minutes. After air-drying, the temperature was raised to 180°C to solidify, thereby creating a polymer-coated graphite plate.

An H type with a magnetic diaphragm was used as the las cell, a polymer-coated graphite plate was used as the cathode, a platinum plate (2 x 501 fl) was used as the anode, and a saturated calomel electrode (SCE) was used as the reference electrode for the cathode.

In the anode chamber, 50ml of NaC 1100g/l aqueous solution was added.
, while maintaining the pH at 6.6 using IN NaOH solution. In the cathode chamber, 50 ml of an aqueous solution consisting of 0.1N NaOH and 10.2% sodium metaphosphate was circulated while being saturated with oxygen gas.

Constant potential electrolysis was carried out for 3 hours while maintaining the cathode potential at 10.4 V (vs. 5 CE). After electrolysis, analysis of the anolyte reveals NaCl
0=0.016g and a trace amount of NaCl○ was generated.

Analysis of the catholyte revealed 20,009 g of H2O and NaOH
0.032 g was generated. Analysis of H2O2 is Ti (■)
A colorimetric method was used.

"Example 6" Using 200 meshes of 2% divinylbenzene-bistyrene polymer, polymer beads of tyrene polymer having hydroquinone side chains were synthesized.

Graphite (2 parts 5c
m), anode - diplatinum (2X5cTI+) was used, and a saturated calomel electrode (SCE) was used as the reference electrode on the cathode side.

10ml of polymer beads and 10m of 200 mesh activated carbon
A mixture of 0.1 and 0.1 was placed in contact with the graphite cathode. IN
The cathode chamber was filled with 50 ml of NaOH. The anode chamber was charged with 50 liters of NaCl aqueous solution at 100 g/liter.

When electrolysis was carried out for 5 hours at a cathode potential of -0.4 V (vs. 5 CE), 0.006 g of chlorine was generated from the anode.

Only the polymer beads were separated, packed in a glass column with a diameter of 10 mm, and 50 ml of an oxygen-saturated 0.2% sodium metaphosphate aqueous solution was circulated for 5 hours.
2g of hydrogen peroxide was produced. In addition, there is 0.0% in the catholyte.
007g of NaOH increased.

Claims (1)

[Claims] 1. An alkali metal halide aqueous solution is supplied to the anode chamber of an electrolytic cell separated by a diaphragm into an anode chamber and a cathode chamber, and an organic compound or redox resin having oxygen reducing ability is supplied to the cathode chamber. Hydrogen peroxide is produced by supplying an alkaline aqueous solution and electrolyzing with a direct current in the presence of oxygen, and bringing the reduced form of an organic compound or redox resin produced in the cathode chamber into contact with oxygen. A method for producing hydrogen peroxide. 2. The method for producing hydrogen peroxide according to claim 1, wherein the alkali metal halide is an alkali metal chloride. 3. The method for producing hydrogen peroxide according to claim 1, wherein the organic compound having oxygen reducing ability is a water-soluble anthraquinone derivative or naphthoquinone derivative. 4. The method for producing hydrogen peroxide according to claim 1, wherein the redox resin is a quinone redox resin.