JPH06106046A - Production of hydrogen peroxide - Google Patents

Abstract

PURPOSE:To easily control, to shorten the residence time of a working liquid, to produce in a flow system and to improve productivity by using a separation membrane in an oxidation-reduction process. CONSTITUTION:In a reduction process, a working liquid 1 is transferred to a separation membrane module or separation membrane element 4 by a pump 2 and hydrogen 7 is fed into the other side of the separation membrane. In an oxidizing process, a working liquid 5 is transferred to a separation membrane module or separation membrane element 11 by a pump 9 and oxygen 14 is fed into the other side of the separation membrane. Since the gas-liquid mixing reactor using a gas permeable membrane performs gas-liquid mixing by using a vapor-liquid equilibrium relationship, gas more than that in a saturated state is not mixed in. Therefore it is not possible that excess gas not required for reaction is mixed in to generate insufficiently dissolved bubbles in the working liquid. In addition, the feed quantity of gas to the working liquid is controlled by a simple operation and reduction or oxidation reaction us performed uniformly and in a short time, in a flow system.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a method for producing hydrogen peroxide using quinones.

[0002]

BACKGROUND ART Hydrogen peroxide is industrially (1) a reducing step of hydrogenating a working fluid (I) containing quinones in the presence of a catalyst to produce a hydroquinone compound, and (2) a working fluid (I
An oxidation step of oxidizing the hydroquinone compound in I) to generate a quinone compound and hydrogen peroxide, (3) an extraction step of extracting the generated hydrogen peroxide from the working fluid (III), (4)
After the extraction step, the hydraulic fluid (IV) is regenerated and is regenerated for recycling in the reduction step. Then, it is necessary to inject and mix hydrogen into the working fluid in the reducing step of (1) and oxygen in the oxidizing step of (2). However, a method of directly injecting hydrogen into the reaction tank or the flowing liquid pipe, a static mixer, etc. It was common to mix using. Also,
In the extraction step (3), a large amount of water was generally mixed and extracted by the decantation method.

[0003]

When the gas is mixed into the working fluid by directly injecting it into the liquid flow pipe, the gas is merely blown at a pressure higher than the pressure of the liquid flow, so that uniform mixing and It takes time to reach a high reaction rate, and a large-capacity reaction tank must be installed to retain the working fluid. In addition, even if a static mixer is used, it is difficult to control because the variation of the injection amount is large, so it takes time to reach uniform mixing and a high reaction rate, and a large-capacity reaction tank is installed to retain the working fluid. The problem of having to remain remains.

In the extraction by the decantation method, the mixing time is lengthened or a large amount of extracted water is used in order to increase the extraction rate, and moreover, a long time is required for complete liquid-liquid separation. A large-capacity extraction tower or separation tower must be installed. Further, since the concentration of hydrogen peroxide in the extract is low, a concentration step is required, and there is a problem of energy for evaporating water.

[0005]

The object of the present invention can be basically solved by a method for producing hydrogen peroxide which is characterized in that a separation membrane is used in a redox process.

The separation membrane is a gas separation membrane, a pervaporation membrane, a reverse osmosis membrane, a nanofiltration membrane, a dialysis membrane, an ultrafiltration membrane, a microfiltration membrane, an ion exchange membrane, a degassing membrane,
This refers to an insufflation film, etc., and there may be changes in the material and microstructure of the film such as a single film, a composite film, a homogeneous film, a heterogeneous film, a uniform film, and a non-uniform film.

The material of the membrane is cellulose, cellulose acetate, polyacrylonitrile, polymethylmethacryl, polysulfone, polyethersulfone, polyamide, polyester, polycarbonate, polyurethane, polyurea, polymethylpentene. system,
Polysulfide type, polysulfide sulfone type, polyether type, polyether ketone type, polyethylene type,
Polypropylene-based, polysiloxane-based, polyvinyl chloride-based, polyvinylidene fluoride-based, polytetrafluoroethylene-based, epoxy resin-based, or organic compounds such as polymers made of a combination thereof or alumina-based, zirconia-based, silica-based, zeolite-based Alternatively, an inorganic material such as a system in which these are combined can be used.

Further, it may be a separation membrane which is treated with chemicals, radiation or heat to change its characteristics such as chemical resistance, heat resistance and surface energy. For example, a hydrophilic membrane, a hydrophobic membrane or a parent membrane. It may be a hydrophobic membrane.

The structure of the membrane may be any of a film, a plate, a hollow fiber, a capillary, a tube or a pipe, but it is compact and the surface area of the membrane can be increased to enhance the effect of solving the problems of the present invention. Therefore, a film shape, a hollow fiber shape, or a capillary shape is preferable, and a hollow fiber shape is more preferable.

The separation membrane is used by incorporating it into an element or module, but the shape of the element or module is not particularly limited.

The quinones used in the working fluid refer to a quinone compound or a mixture of a hydroquinone compound and a quinone compound obtained by reducing the quinone compound. The quinone compound is generally a monoalkylanthraquinone,
Dialkyl anthraquinone and 2,3-dialkylnaphthoquinone are known and are usually quinone compounds having a C _{2 to} C ₄ alkyl group.

As the solvent, a mixture of aromatic hydrocarbon and alcohols or esters is used in order to dissolve the quinone compound and the hydroquinone compound.

As the hydrogenation catalyst, palladium, Raney nickel, etc. are generally used, but in the present invention, it is effective and preferable to fix them on the surface or inside of the separation membrane.

As a method for supporting the catalyst on the separation membrane,
Either a method of supporting the catalyst during film formation by dispersing the catalyst in the membrane forming stock solution, a method of supporting the catalyst dispersion after the membrane formation by permeating the catalyst dispersion liquid, or further chemical treatment may be added. The loading may be either physical or chemical.

The method of permeating and reacting hydrogen or a gas containing hydrogen or oxygen or a gas containing oxygen with the working fluid through the separation membrane to cause a reaction is not particularly limited, and the working fluid is flowed to one side of the gas permeable membrane, A gas-liquid mixed reaction characterized in that hydrogen or a gas containing hydrogen, or oxygen or a gas containing oxygen is caused to flow through the membrane by passing hydrogen through the surface on the opposite side of the membrane, and the gas is mixed in a working liquid to cause a reaction. It is basically achieved by using a device.

An example of the preferred configuration of the present invention is as shown in FIG. 1, but the present invention is not limited to this. In the reduction step, the working fluid (I) 1 is usually sent by the pump 2 to the separation membrane module or the separation membrane element 4, but it is also possible to supply it by pressure without using a pump. Hydrogen 7 is supplied to the other side of the separation membrane. The working fluid (I) side and the hydrogen side are separated by a separation membrane, and the working fluid (I) does not flow into the hydrogen side. Since the membrane area per module or element is large, hydrogen is well dispersed and supplied, the reduction reaction occurs uniformly, and the working fluid (I
I) 5 is obtained. It is also possible to raise the reduction reaction rate by refluxing a part of it through the bypass line 6. Further, equipment for adjusting the supply pressure, flow rate, temperature, etc. of the working fluid (I) and hydrogen may be further added,
It is also possible to use a plurality of modules or elements in series or in parallel.

In the oxidation step, the working fluid (II) 5 is usually sent to the separation membrane module or the separation membrane element 11 by the pump 9, but it is also possible to supply it under pressure without using a pump. Oxygen 14 is supplied to the other side of the separation membrane. The hydraulic fluid (II) side and the oxygen side are separated by a separation membrane, and the hydraulic fluid (II) does not flow into the oxygen side. Since the membrane area per module or element is large, oxygen is well dispersed and supplied, and the oxidation reaction occurs uniformly,
A hydraulic fluid (III) 12 is obtained. It is also possible to raise the oxidation reaction rate by refluxing a part of it through the bypass line 13. Further, equipment for adjusting the supply pressure, flow rate, temperature, etc. of the hydraulic fluid (II) or oxygen may be further added, and a plurality of modules or elements may be used in series or in parallel.

A gas-liquid mixing reactor using a gas permeable membrane is
Since gas-liquid mixing is performed by utilizing the equilibrium relationship between gas-liquid, there is no possibility of mixing gases above the saturated state.
Unlike the case where the conventional direct injection method or the gas-liquid mixing method using a static mixer is adopted, an excessive amount of gas that is unnecessary for the reaction is not mixed and bubbles that are insufficiently dissolved are not formed in the working fluid. Moreover, by adjusting the hydraulic fluid supply pressure, gas pressure, gas flow rate, and hydraulic fluid temperature, the amount of gas injected into the hydraulic fluid can be controlled arbitrarily and by simple operation, and in a uniform, short-time, fluid system. A reduction or oxidation reaction can be carried out.

As a method of taking out hydrogen peroxide from the working liquid through the separation membrane, a method of directly separating by using a membrane that allows only hydrogen peroxide to permeate, an extraction solvent system containing hydrogen peroxide (for example, water, etc.) is used. The membrane is separated from the working fluid, or the working fluid containing hydrogen peroxide is caused to flow on one surface of the separation membrane and the extraction solvent (for example, water) is caused to flow on the opposite surface of the membrane so that the hydrogen peroxide permeates the membrane. A good method is to separate them.

The basic constitution of the present invention is as shown in FIG. 1. Normally, the working fluid (III) is sent to the separation membrane module or the separation membrane element 18 by the pump 16, and water is supplied to the other side of the separation membrane. 21 is supplied by the pump 22, but it is also possible to supply by pressure without using the pump. The hydraulic fluid (III) side and the water side are separated by a separation membrane, and the hydraulic fluid (III) does not flow into the water side. Since the membrane area per module or element is large, water extraction of hydrogen peroxide occurs uniformly on the entire membrane surface, and hydrogen peroxide solution 24 is obtained. It is also possible to raise the hydrogen peroxide concentration by refluxing a part of it through the bypass line 25.
It is also possible to raise the hydrogen peroxide extraction rate by refluxing a part of the working liquid (IV) obtained after the hydrogen peroxide extraction through the bypass line 20. Furthermore, equipment for adjusting the supply pressure, flow rate, temperature, etc. of the hydraulic fluid (III) or water may be further added, and it is also possible to use a plurality of modules or elements in series or in parallel.

In the separation of hydrogen peroxide using a separation membrane, the hydrogen peroxide dispersed without being dissolved in the working fluid (III) is captured by the membrane surface having a large area and dissolved in the extracted water. As when the decantation method of
There is no need to use a large amount of water or to stand still for liquid-liquid separation in a large capacity tank after mixing a large amount of water. Moreover, by adjusting the supply pressure, flow rate, and temperature of the hydraulic fluid (III) and water, the concentration and extraction rate of the hydrogen peroxide solution can be controlled arbitrarily and by simple operation. The extraction process can be carried out with.

The working fluid (IV) after the hydrogen peroxide extraction is sent to the separation membrane module or the separation membrane element 29 by the pump 27, and the working fluid (I) regenerated by removing the side reaction products and decomposition products by the membrane treatment. ) Is sent to the reduction process,
It is also possible to supply by pressure without using a pump. It is also possible to improve the filtration efficiency by refluxing a part of the flow through the bypass line 30.

Further, equipment for adjusting the supply pressure, flow rate, temperature, etc. of the hydraulic fluid (IV) may be further added, and a plurality of modules or elements can be used in series or in parallel.

In the regeneration of the working fluid using the separation membrane, the regeneration efficiency can be arbitrarily and easily controlled by adjusting the supply pressure, the flow rate and the temperature of the working fluid (IV). Instead, a large volume of hydraulic fluid can be regenerated in a fluid system.

[0025]

EXAMPLES Next, the present invention will be explained based on examples.
This is by no means limiting.

Example 1 A polytetrafluoroethylene resin porous hollow fiber membrane (separation pore diameter 0.2 μm, inner diameter / outer diameter = 0.6 mm / 1.0 mm) was prepared by the method described in JP-A-1-34408. Was produced. Both ends of this bundle of hollow fiber membranes were sealed with an adhesive to prepare a hollow fiber membrane module (effective length 50 cm × 3000 pieces) in which the inside and outside of the hollow fiber membrane were distinguished.

Then, a 1% aqueous solution of palladium chloride was added at 90 ° C.
Heated to pH 10 ± 0.5 with sodium hydroxide solution.
37% formalin with a volume of 1/50 was added dropwise while maintaining the above temperature, and the solution was circulated while passing through the hollow fiber membrane, washed with pure water and dried under reduced pressure to obtain a catalyst-supporting membrane. (Palladium weight = 210 g) / (membrane weight = 660 g) = 31.8%.

Inside the hollow fiber membrane, 30.0 g of 2-ethylanthraquinone was added to a solvent containing 75% by volume of C ₉ -alkylbenzene and 25% by volume of trioctyl phosphate.
7 liters of 2-ethyltetrahydroanthraquinone
Working fluid containing 0.0 g / liter at 45 ° C, 0.5 ton /
The hydrogen gas is supplied for 1.5 hours from the outside of the hollow fiber membrane.
It was supplied at a pressure of / cm ² . The composition of the hydraulic fluid on the outlet side is 2
-Ethylanthraquinone 30 g / liter, 2-ethyltetrahydroanthraquinone 36.5 g / liter, 2-ethyltetrahydroanthrahydroquinone 3
It was 3.8 g / liter.

Example 2 The same hollow fiber membrane module as in Example 1 was used except that palladium was not supported, and Example 1 was placed inside the hollow fiber membrane.
The working fluid obtained in Step ² was supplied at 50 ° C. at 0.5 ton / hour, and oxygen gas was supplied from the outside of the hollow fiber membrane at a pressure of 1.5 kg / cm ² . The composition of the working fluid on the outlet side was as follows: 2-ethylanthraquinone 30.0 g / liter, 2-ethyltetrahydroanthraquinone 69.8 g / liter, 2-
0.2 g of ethyltetrahydroanthrahydroquinone /
It was liter and hydrogen peroxide 5.1 g / liter.

Example 3 The same hollow fiber membrane module as in Example 2 was used except that it was hydrophilized with ethanol, and the working fluid obtained in Example 2 was placed inside the hollow fiber membrane at 0.5 ton / hour. Then, pure water (30 ° C.) was supplied to the outside of the hollow fiber membrane at 0.005 ton / hour to extract hydrogen peroxide from the working liquid. The concentration of hydrogen peroxide in the extracted water was 30.3% by weight.

[0031]

According to the present invention, hydrogen peroxide can be produced by a small apparatus which is easy to control and has a small installation space. Further, since hydrogen peroxide can be manufactured near the place of consumption, it is possible to connect directly to the consumption line, and it is also possible to reduce transportation costs and the like. In addition, the residence time of the hydraulic fluid is short,
Since it can be manufactured in a fluid system, the production efficiency is high, and the effect is great in terms of quality and energy saving.

[Brief description of drawings]

FIG. 1 is an example of the method of the redox reaction of the present invention.

[Explanation of symbols]

 1: working fluid (I) 2: pump 3: filter 4: separation membrane module or separation membrane element 5: working fluid (II) 6: bypass line 7: hydrogen 8: separation membrane 9: pump 10: filter 11: separation membrane Module or separation membrane element 12: hydraulic fluid (III) 13: bypass line 14: oxygen 15: separation membrane 16: pump 17: filter 18: separation membrane module or separation membrane element 19: hydraulic fluid (IV) 20: bypass line 21 : Water 22: Pump 23: Filter 24: Hydrogen peroxide water 25: Bypass line 26: Separation membrane 27: Pump 28: Filter 29: Separation membrane module or separation membrane element 30: Bypass line 31: Separation membrane

Claims (6)

[Claims] 1. A method for producing hydrogen peroxide, which comprises using a separation membrane in the redox step. 2. A reduction step of (1) hydrogenating a working fluid (I) containing quinones in the presence of a catalyst to produce a hydroquinone compound, and (2) oxidizing a hydroquinone compound in the working fluid (II). Oxidation step for producing quinone compound and hydrogen peroxide, (3) Separation step for separating generated hydrogen peroxide from working fluid (III), and (4) Regeneration and reduction step for working fluid (IV) after separation step Has a step including at least the steps (1) and (2) selected from the group consisting of a regeneration step for recycling and using a separation membrane in at least the step (1) or (2) A method for producing hydrogen peroxide, comprising: 3. A hydrogen-containing working fluid containing the quinone according to claim 1 is added in the presence of a catalyst to produce a hydroquinone compound, and hydrogen is permeated and mixed through a separation membrane. A method for producing hydrogen peroxide, which comprises reacting. 4. In the oxidation step of oxidizing the hydroquinone compound according to claim 2 (2) to generate a quinone compound and hydrogen peroxide, oxygen is permeated and mixed through a separation membrane to react. Method for producing hydrogen peroxide. 5. A method for producing hydrogen peroxide, wherein in the step (3) of separating hydrogen peroxide produced from a working fluid, hydrogen peroxide is taken out through a separation membrane. 6. A method for producing hydrogen peroxide, wherein at least one of the separation membranes according to claims 1, 2, 3, 4, and 5 is a hollow fiber membrane.