JPH0769605A - Production of hydrogen peroxide - Google Patents

Abstract

PURPOSE:To obtain concd. H2O2 with high hydrogen selectivity without incorporating halogen into an aq. solp. by allowing O2 to react with H2 with a modified platinum-group metal catalyst on which an element selected from copper, iron, nickel, etc., and a platinum-group metal are simultaneously deposited. CONSTITUTION:An element selected from Cu, Fe, Ni and Co and a platinum- group metal are deposited on a carrier (zirconium oxide, aluminum oxide, silicon oxide, titanium oxide, etc.) to prepare a modified platinum-group metal catalyst. O2 is allowed to catalytically react with H in a reaction medium by using the catalyst to obtain H2O2. The medium is formed with an aq. acidic soln. free of halogen and contg. an H2O2 stabilizer such as aminotri(methylenephosphonic acid) and pyrophosphoric acid.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to an improved process for catalytically reacting oxygen and hydrogen in a reaction medium to produce hydrogen peroxide. More specifically, the present invention relates to a method for producing hydrogen peroxide by reacting oxygen and hydrogen in the presence of a platinum group catalyst in a reaction medium containing no cocatalyst such as halogen ions.

[0002]

2. Description of the Related Art Currently, the main method of industrially producing hydrogen peroxide is an autoxidation method using alkylanthraquinone as a medium. The problem with this method is that it requires many steps such as reduction of alkylanthraquinone, oxidation, extraction and separation of the produced hydrogen peroxide, purification and concentration, which complicates the process, resulting in equipment costs and operating costs. Is large. Further, there are problems such as loss due to deterioration of alkyl anthraquinone and deterioration of activity of the reduction catalyst. In order to improve these problems, a manufacturing method other than the above manufacturing method has been attempted, and one of them is
There is a method of producing hydrogen peroxide directly from oxygen and hydrogen using a catalyst in a reaction medium. For example, a method of producing hydrogen peroxide from oxygen and hydrogen using a platinum group metal as a catalyst has been proposed, and it is known that a considerable concentration of hydrogen peroxide is produced (for example, Japanese Patent Publication No. 56- No. 47121,
JP-B-55-18646, JP-B-1-23401, JP-A-63-15600
No. 5). In each of these, an aqueous solution in which an acid or an inorganic salt is dissolved is used as a reaction medium. In particular, it has been shown that by including a halogen ion in the reaction medium, the activity of the catalyst is suppressed, the selectivity of the hydrogen peroxide generation reaction is significantly improved, and the concentration of hydrogen peroxide obtained is increased. That is, in JP-A-63-156005, a platinum group catalyst is used,
In the method for producing hydrogen peroxide from oxygen and hydrogen under pressure in sulfuric acid aqueous solution, it is possible to selectively produce high concentration hydrogen peroxide by coexisting halogen ions such as bromide ion in the aqueous solution. Is shown. That is, in the conventional technique, in order to catalytically react oxygen and hydrogen in a reaction medium to obtain hydrogen peroxide with high selectivity, a reaction is performed in an acidic aqueous solution using a cocatalyst such as a halogen ion. It was a thing.

[0003]

DISCLOSURE OF THE INVENTION In a method for producing hydrogen peroxide by catalytically reacting oxygen and hydrogen in a reaction medium, the conventional known technique is to obtain a practical concentration of hydrogen peroxide. It was necessary to coexist an acid and a halogen ion in the reaction medium. However, when a high concentration of halogen ions is present in the acidic reaction medium, the material of the apparatus that can be used for handling the same is limited, and as a result, an expensive corrosion-resistant reaction container is required, which is an economical problem. . Furthermore, in such a reaction system, there is a problem that the platinum group metal, which is an active component of the catalyst, is eluted into the reaction medium. In particular, the amount of platinum group metal eluted increases in proportion to the concentration of halogen ions. The elution of the platinum group metal component causes a decrease in catalyst activity and a decrease in catalyst life, and becomes a serious economic problem when hydrogen peroxide is produced by an industrial continuous operation. Furthermore, the method of carrying out the reaction in the presence of halogen ions requires a purification step for removing the halogen ions from the produced hydrogen peroxide. As described above, the conventional technique has various problems.

[0004]

The present inventors have used a platinum group catalyst in the presence or absence of an inert gas such as nitrogen, which does not adversely affect the present reaction, in a reaction medium using oxygen and hydrogen. In the method for producing hydrogen peroxide by catalytically reacting with, as a result of continuing the examination of the production method for obtaining a high concentration of hydrogen peroxide in a reaction medium containing no halogen ion, copper,
By using a platinum group metal catalyst modified with at least one element selected from the group consisting of iron, nickel and cobalt, a high concentration of hydrogen peroxide can be obtained using an acidic aqueous solution containing no halogen ion as a reaction medium. I found a thing. That is, the present invention is a method for producing hydrogen peroxide by catalytically reacting oxygen and hydrogen in a reaction medium, wherein the catalyst is at least one selected from the group consisting of copper, iron, nickel and cobalt. A method for producing hydrogen peroxide, which comprises using a modified platinum group metal catalyst in which the above elements and a platinum group metal are both supported on a carrier. In the present invention, an acidic aqueous solution containing no halogen ion can be used as the reaction medium.

The catalyst used in the present invention may be prepared, for example, by using at least one selected from the group consisting of a salt of a platinum group metal and copper, iron, nickel or cobalt on a carrier used for ordinary catalyst preparation. It is possible to adopt a method in which the catalyst is prepared by simultaneously supporting the salt of the element (1), and then calcining and reducing the salt. Furthermore, the catalyst is prepared by carrying a salt of at least one element selected from the group consisting of copper, iron, nickel, or cobalt on a catalyst on which a platinum group metal is previously supported, and then calcining and reducing the salt. Alternatively, the platinum group metal may be supported on a catalyst in which a salt of at least one element selected from the group consisting of copper, iron, nickel or cobalt is previously supported, and then the platinum group metal is calcined and reduced. The catalyst may be prepared by

In the present invention, as the platinum group metal, specifically, palladium, platinum or the like can be used alone or as a mixture or alloy. Further, it is also possible to use a mixture or alloy containing ruthenium, osmium, rhodium, iridium or gold, which is mainly composed of them. Particularly, a catalyst containing palladium as a main component is preferably used. Examples of salts of platinum group metals include palladium, platinum,
There may be mentioned ruthenium, osmium, rhodium, iridium or gold salts, preferably palladium or platinum nitrates, salts such as hydrochlorides, sulfates or acetates, and complexes such as palladium or platinum tetraammine complexes. The loading amount of the platinum group metal is usually 0.1 to 10 with respect to the carrier.
% By weight.

Examples of the copper, iron, nickel or cobalt salts include salts of copper, iron, nickel or cobalt nitrates, hydrochlorides, sulfates or acetates. The amount of copper, iron, nickel and cobalt in the modified platinum group metal catalyst used in the present invention is at least 1/2 times the weight of the platinum group metal, preferably at least 10 times the weight of the platinum group metal. There is no particular limitation as a carrier used for the catalyst of the present invention, and any catalyst carrier can be used. Among them, a carrier having a large mechanical strength or specific surface area of the catalyst, that is, zirconium oxide, aluminum oxide. ,
Silicon oxide, titanium oxide, zeolite, silica-alumina, activated carbon, adsorption resin, ion exchange resin and the like are preferable.
Zirconium oxide is particularly preferred as a carrier when modified with copper or iron.

The amount of the catalyst used in the production of hydrogen peroxide of the present invention is usually 1 gram or more per liter of the reaction medium, and it may be used in the form of a slurry. An aqueous solution is preferable as a reaction medium in the production of hydrogen peroxide of the present invention, particularly an acidic solution containing no halogen ion can be used, and an acidic aqueous solution containing an inorganic acid containing no halogen ion such as sulfuric acid, nitric acid or phosphoric acid is most preferable. It is preferably used. Known stabilizers for preventing hydrogen peroxide decomposition (for example, aminotri (methylenephosphonic acid), 1-hydroxyethylidene-1,1-diphosphonic acid, ethylenediaminetetra (methylenephosphonic acid), pyrophosphoric acid, or salts thereof. The reaction conditions in the production of hydrogen peroxide of the present invention are usually reaction pressure of 3 to 150 kg / cm ² ·.
G, the reaction temperature is 0 to 50 ° C., and the reaction time is 30 minutes to 6 hours.

[0009]

EXAMPLES The present invention will be described in more detail with reference to Examples and Comparative Examples. In Examples and Comparative Examples, the gas composition was analyzed by gas chromatography, and the concentration of hydrogen peroxide in the solution was measured by titration with a potassium permanganate solution under sulfuric acid acidity. Example 1 A modified platinum group metal catalyst was prepared by the following method.
That is, commercially available zirconium oxide (Kosou Chemical Co., Ltd.)
10 g) was suspended in 100 ml of water,
5.70 g of commercially available copper nitrate (manufactured by Kosou Chemical Co., Ltd.)
Diluted solution of aqueous solution and palladium nitrate solution dissolved in 0 ml of water (Ishifuku Metal Industry Co., Ltd., 1 g-Pd / liter)
50 ml of the mixed solution was added dropwise. After the completion of dropping, the suspension was evaporated to dryness on a hot plate and further dried in a dryer at 110 ° C. for 24 hours. After that, it is fired in an air stream at 500 ° C. for 2 hours and then in a hydrogen stream for 120 hours.
The catalyst was obtained by reduction at 1 ° C. for 1 hour. The following operation was performed as a reaction method for directly producing hydrogen peroxide from oxygen and hydrogen. In a glass container having an internal volume of 65 ml, 10 g of an aqueous solution prepared to have a sulfuric acid content of 0.1 mol / liter was placed. To this aqueous solution was added 50 mg of the supported palladium catalyst prepared as described above, and the glass container was placed in an autoclave having a volume of 100 ml. Hydrogen gas was 3.5% by volume, oxygen gas was 35% by volume, and nitrogen gas was 61.5% by volume. After performing a pressure test with a mixed gas having a composition of 10%, the gas having the same composition was pressurized to 50 kg / cm ² · G. The mixture was stirred at 2,000 rpm for 1 hour while maintaining the temperature at 10 ° C. After completion of stirring, the hydrogen peroxide concentration in the reaction medium was 0.17% by weight, and the hydrogen selectivity was 57%. The hydrogen selectivity was calculated by the following formula.

[Equation 1] Hydrogen selectivity (%) = [(mol amount of hydrogen peroxide produced by reaction) / (mol amount of theoretical production of hydrogen peroxide calculated from amount of hydrogen consumed)] × 100

Example 2 Instead of using 10 g of water as the reaction medium, 75 pp
A catalyst was prepared and reacted in the same manner as in Example 1 except that 10 g of an aqueous solution containing m of ethylenediaminetetra (methylenephosphonic acid) was used. After completion of stirring for 1 hour, the concentration of hydrogen peroxide in the reaction medium was 0.25% by weight, and the hydrogen selectivity was 65%.

Example 3 In preparing a modified platinum group metal catalyst, commercially available titanium oxide (TAYCA) was used instead of 10 g of commercially available zirconium oxide.
Except that 10 g of anatase type manufactured by Co., Ltd. was used,
The same operation as in Example 1 was carried out to prepare a catalyst and carry out a reaction. After completion of stirring for 1 hour, the hydrogen peroxide concentration in the reaction medium was 0.12% by weight, and the hydrogen selectivity was 15%.

Example 4 Commercially available copper nitrate 5.7 was used in preparing the modified platinum group metal catalyst.
Commercially available ferric nitrate instead of 0 g (Kosou Chemical Co., Ltd.)
The same operation as in Example 1 was carried out to prepare a catalyst and carry out a reaction except that 10.85 g of (produced) was used. After stirring for 1 hour, the hydrogen peroxide concentration in the reaction medium was 0.17% by weight, and the hydrogen selectivity was 60%.

Example 5 When preparing a modified platinum group metal catalyst, a commercially available titanium oxide (T
A catalyst was prepared and reacted in the same manner as in Example 4, except that 10 g of anatase type manufactured by AYCA Corporation was used. After stirring for 1 hour, the hydrogen peroxide concentration in the reaction medium was 0.14% by weight, and the hydrogen selectivity was 23%.
Met.

Example 6 Similar to Example 4, except that 10 g of commercially available silicon dioxide (manufactured by Fuji Silysia KK) was used as a carrier instead of 10 g of commercially available zirconium oxide in the preparation of the modified platinum group metal catalyst. The operation was carried out to prepare a catalyst and carry out a reaction.
After completion of stirring for 1 hour, the hydrogen peroxide concentration in the reaction medium was 0.13% by weight, and the hydrogen selectivity was 17%.

Example 7 In the preparation of the modified platinum group metal catalyst, Example 4 was used except that 10 g of commercially available aluminum oxide (manufactured by Mizusawa Chemical Co., Ltd., activated alumina) was used as the carrier instead of 10 g of commercially available zirconium oxide. The same operation was performed to prepare a catalyst and carry out a reaction. After completion of stirring for 1 hour, the hydrogen peroxide concentration in the reaction medium was 0.13% by weight, and the hydrogen selectivity was 1.
It was 8%.

Example 8 In preparing a modified platinum group metal catalyst, commercially available nickel nitrate (manufactured by Komune Chemical Co., Ltd.) was used in place of 5.70 g of commercially available copper nitrate (manufactured by Komune Chemical Co., Ltd.). The same operation as in Example 1 was carried out except that 43 g was used to prepare a catalyst and carry out a reaction. After stirring for 1 hour, the hydrogen peroxide concentration in the reaction medium was 0.13% by weight and the hydrogen selectivity was 17%.
%Met.

Example 9 Example 8 was repeated except that 10 g of a commercially available aluminum oxide (activated alumina, manufactured by Mizusawa Chemical Co., Ltd.) was used as a carrier instead of 10 g of a commercially available zirconium oxide in the preparation of the modified platinum group metal catalyst. The same operation was performed to prepare a catalyst and carry out a reaction. After completion of stirring for 1 hour, the hydrogen peroxide concentration in the reaction medium was 0.14% by weight, and the hydrogen selectivity was 1.
It was 9%.

Example 10 In preparing a modified platinum group metal catalyst, commercially available copper nitrate 5.7 was used.
A catalyst was prepared and reacted in the same manner as in Example 1 except that 7.41 g of commercially available cobalt nitrate (manufactured by Komune Chemical Co., Ltd.) was used instead of 0 g. After stirring for 1 hour, the hydrogen peroxide concentration in the reaction medium was 0.12.
% By weight and hydrogen selectivity was 17%.

Example 11 In preparing a modified platinum group metal catalyst, commercially available copper nitrate 5.7 was used.
Instead of an aqueous solution in which 0 g was dissolved, an aqueous solution in which 2.85 g of commercially available copper nitrate (manufactured by Kosou Chemical Co., Ltd.) and 3.72 g of commercially available nickel nitrate (manufactured by Kosou Chemical Co., Ltd.) were dissolved Except that it was used, the same operation as in Example 1 was carried out to prepare a catalyst and carry out a reaction. After completion of stirring for 1 hour, the hydrogen peroxide concentration in the reaction medium was 0.14% by weight, and the hydrogen selectivity was 40%.

Example 12 Commercially available ferric nitrate 1 in preparing a modified platinum group metal catalyst
Instead of the aqueous solution in which 0.85 g was dissolved, commercially available ferric nitrate 5.43 g and commercially available cobalt nitrate 3.71 g (Kosou Chemical Co., Ltd.) were dissolved. The same procedure as in Example 4 was carried out except that an aqueous solution was used to prepare a catalyst and carry out a reaction. After stirring for 1 hour,
The hydrogen peroxide concentration in the reaction medium is 0.13% by weight,
The hydrogen selectivity was 38%.

Comparative Example 1 (Examples 1, 4, 8, 10, 1)
(For 1, 12) When preparing the platinum group metal catalyst, the catalyst preparation and reaction were performed in the same manner as in Example 1 except that only palladium was supported on the zirconium oxide support without using commercially available copper nitrate. After completion of stirring for 1 hour, the hydrogen peroxide concentration in the reaction medium was 0.00% by weight, and the hydrogen selectivity was 0%.

Comparative Example 2 (Compared to Examples 3 and 5) In the preparation of the platinum group metal catalyst, the same procedure as in Comparative Example 1 was carried out except that titanium oxide was used instead of zirconium oxide to carry out the catalyst preparation and reaction. It was After completion of stirring for 1 hour, the hydrogen peroxide concentration in the reaction medium was 0.00% by weight, and the hydrogen selectivity was 0%.

Comparative Example 3 (Compared to Examples 7 and 9) In preparation of the platinum group metal catalyst, the same operation as in Comparative Example 1 was carried out except that aluminum oxide was used in place of titanium oxide to carry out catalyst preparation and reaction. It was After completion of stirring for 1 hour, the hydrogen peroxide concentration in the reaction medium was 0.00% by weight, and the hydrogen selectivity was 0%.

Comparative Example 4 (Comparative to Example 6) The catalyst preparation and reaction were carried out in the same manner as in Comparative Example 1 except that silicon dioxide was used instead of titanium oxide when preparing the platinum group metal catalyst. After completion of stirring for 1 hour, the hydrogen peroxide concentration in the reaction medium was 0.00% by weight,
The hydrogen selectivity was 0%.

[0025]

EFFECTS OF THE INVENTION According to the present invention, a high concentration of hydrogen peroxide can be produced with a very high hydrogen selectivity without the need for halogen ions to be present in an aqueous solution as a reaction medium. Also,
According to the present invention, various problems such as the problem of the material of the reaction vessel and the decrease of the catalytic activity, which are caused by the coexistence of a high concentration of halogen ions in the reaction medium, as in the conventional method are solved.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Michiya Kawakami 6-1-1, Shinjuku, Katsushika-ku, Tokyo Mitsubishi Gas Chemical Co., Ltd. Tokyo Research Laboratory

Claims (7)

[Claims] 1. A method for producing hydrogen peroxide by catalytically reacting oxygen and hydrogen in a reaction medium, wherein at least one or more selected from the group consisting of copper, iron, nickel and cobalt is used as a catalyst. A method for producing hydrogen peroxide, which comprises using a modified platinum group metal catalyst in which both the element and the platinum group metal are supported on a carrier. 2. The platinum group metal is palladium.
The method for producing hydrogen peroxide described above. 3. The method for producing hydrogen peroxide according to claim 1, wherein the reaction medium is an acidic aqueous solution containing no halogen ions. 4. The method for producing hydrogen peroxide according to claim 1, wherein the reaction medium is an acidic aqueous solution containing a stabilizer for hydrogen peroxide. 5. A stabilizer of hydrogen peroxide is aminotri (methylenephosphonic acid), 1-hydroxyethylidene-1,
The method for producing hydrogen peroxide according to claim 4, which is at least one selected from the group consisting of 1-diphosphonic acid, ethylenediaminetetra (methylenephosphonic acid), pyrophosphoric acid, and salts thereof. 6. The carrier according to claim 1, wherein the carrier is at least one selected from the group consisting of zirconium oxide, aluminum oxide, silicon oxide, titanium oxide, zeolite, silica-alumina, activated carbon, adsorption resin and ion exchange resin. Method for producing hydrogen peroxide. 7. The support is zirconium oxide, and
The method for producing hydrogen peroxide according to claim 1, wherein a modified platinum group metal catalyst modified with copper or iron is used.