JP3620193B2 - Method for producing hydrogen peroxide - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for producing hydrogen peroxide. More specifically, the present invention relates to a method for producing hydrogen peroxide by directly reacting hydrogen and oxygen.
[0002]
[Prior art]
Hydrogen peroxide is bleach (paper / pulp, natural fiber), industrial chemicals (oxidizers and plasticizers, rubber chemicals, reducing agents such as pollution treatment), pharmaceuticals (oxidizers), foods (fishery processing bleach fungicides) And various other bleaching agents) and is one of the most important industrial products with a wide variety of uses.
[0003]
At present, the most common industrial production method of hydrogen peroxide is based on an autoxidation method using alkylanthraquinone. However, as a problem of this method, many steps such as reduction of alkyl anthraquinone, oxidation, extraction separation of purified hydrogen peroxide, purification and concentration are necessary, and the process is complicated. In addition, loss of alkyl anthraquinone and deterioration of the reduction catalyst are also problematic.
[0004]
In order to solve these problems, a method for directly synthesizing hydrogen peroxide by bringing hydrogen and oxygen into contact with each other in an aqueous medium in the presence of a platinum group metal supported catalyst has been proposed (Japanese Patent Publication No. 55-18646). Gazette, Japanese Examined Patent Publication No. 56-47121, Japanese Examined Patent Publication No. 1-23401, Japanese Unexamined Patent Publication No. 63-156005). In any of these, a solution to which an acid or an inorganic salt is added is used as a reaction medium.
[0005]
For example, in Japanese Patent Application Laid-Open No. 63-156005, a metal catalyst having a platinum group metal supported on a support can be used to produce hydrogen peroxide having a certain high concentration from hydrogen and oxygen in an aqueous medium under high pressure conditions. It is necessary to add a high amount of acid and a compound that dissociates to generate a halogen ion, such as sodium bromide, and a step of adding these is necessary.
[0006]
JP-A-57-92506 discloses alcohols, ketones, ethers, esters, amides and the like as a reaction medium, and particularly describes that methanol is excellent. However, the catalyst system used here is still a metal with a platinum group metal supported on the support, acid and halogen ions, and formaldehyde is also present in methanol to suppress the decomposition of the hydrogen peroxide produced. It was necessary to let them. Therefore, a process for adding these and, in some cases, a process for removing formaldehyde is necessary, which is industrially disadvantageous.
[0007]
[Problems to be solved by the invention]
The problem to be solved by the present invention, i.e., the object of the present invention, is to suppress the decomposition of hydrogen peroxide produced without adding any of acids, halogen ions, and additives such as formaldehyde. It is to provide a method for producing hydrogen peroxide.
[0008]
[Means for Solving the Problems]
In view of the above situation, the present inventors have continued earnestly research on a method for producing hydrogen peroxide in which hydrogen and oxygen are directly reacted in a reaction medium, and have completed the present invention. That is, the present invention relates to a method for producing hydrogen peroxide in which hydrogen and oxygen are reacted in a reaction medium containing a halogen compound of a platinum group metal.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described in detail.
Examples of the platinum group metal in the halogen compound of the platinum group metal used in the present invention include rhodium, iridium, platinum, and palladium. Preferred are platinum and palladium, and more preferred is palladium. As the halogen compounds, fluorine compounds, chlorine compounds, bromine compounds and iodine compounds are used, but chlorine compounds and bromine compounds are preferably used. Specific examples of such a platinum group metal halogen compound include rhodium chloride, rhodium bromide, iridium chloride, iridium bromide, platinum chloride, platinum bromide, palladium fluoride, palladium chloride, palladium bromide, palladium iodide, dichloro. Diammine palladium etc. are mentioned. Preferred are platinum bromide, platinum chloride, palladium chloride, palladium bromide and dichlorodiammine palladium, and particularly preferred are palladium chloride, palladium bromide and dichlorodiammine palladium.
[0010]
In the present invention, a reaction medium is used, and examples thereof include water and organic compounds that are liquid in the reaction system, and mixtures thereof. Examples of such organic compounds include alcohols, ketones, ethers, esters, amides and the like. The reaction medium used in the present invention is preferably water and / or alcohol. More preferably, it is alcohol alone or a mixed solution of alcohol and water. In the case of the mixed solution, it is preferable that the volume is preferably 80% or more, more preferably 90% or more of alcohol.
[0011]
Specific examples of the alcohol include alcohols having 1 to 8 carbon atoms such as methanol, ethanol and isopropyl alcohol, preferably alcohols having 1 to 4 carbon atoms, glycols such as ethylene glycol, and the like. May also be used as a mixture. Methanol and ethanol are preferable, and methanol is more preferable.
[0012]
In the present invention, a high-concentration hydrogen peroxide solution can be obtained without adding an acid. However, if the coexistence of the acid in the hydrogen peroxide solution after the reaction does not matter, sulfuric acid, hydrochloric acid, phosphoric acid An acid such as may be added.
[0013]
The amount of the platinum group metal halogen compound is not particularly limited, but is usually 1 mg or more, preferably 10 mg or more, per 100 ml of the reaction solution. The form of the platinum group metal halogen compound may be any fine powder, pellet, or the like, but a fine powder is preferable, and a surface area of 0.01 to 10,000 m ² / g is preferably used. In the present invention, a platinum group metal halogen compound may be used singly or supported on a suitable carrier. In general, the support has a higher activity per metal weight.
[0014]
Examples of the carrier include alumina, silica, titania, magnesia, zirconia, ceria, zeolite, graphite, activated carbon, silica gel, hydrous silicic acid, silicon carbide, etc., and alumina, silica, titania, zeolite, graphite, activated carbon are preferable. Used.
[0015]
The method of supporting the carrier is not particularly limited as long as it can be supported, for example, a method of suspending the carrier in a solution of a halogen compound of a platinum group metal and evaporating to dryness.
[0016]
The reaction of the present invention can be either a continuous type or a batch type, and the reaction apparatus can be a suspension bed type, a fixed bed type, or the like. None of these are particularly limited.
[0017]
For example, the reaction of the present invention can be carried out by a method in which a halogen compound of a platinum group metal is put in a reaction medium and hydrogen and oxygen gases are bubbled therein. When carrying out such a method, for the purpose of bringing the reaction gas bubbles into contact with the reaction medium for a longer period of time, a solvent that is incompatible with the reaction medium is further added to carry out the reaction under strong stirring. Sometimes. As such a solvent, for example, when methanol is used as a reaction medium, octane or the like can be selected. The amount of such a solvent used may be any amount as long as it does not inhibit the reaction, but is generally used in an amount of 80% or less, preferably 70% or less in volume.
[0018]
The partial pressure ratio of oxygen and hydrogen can be implemented in the range of 1:50 to 50: 1. The reaction can be carried out by diluting with an inert gas or using air instead of oxygen, but for safety reasons, it is preferable to carry out the reaction outside the explosion range. The reaction temperature is generally 5 ° C to 70 ° C, preferably 10 ° C to 50 ° C. The reaction pressure is not particularly limited, but is carried out in the range of atmospheric pressure to 150 kg / cm ² · G, particularly 5 to 50 kg / cm ² · G.
[0019]
【Example】
Hereinafter, although an example and a comparative example explain the present invention still in detail, the present invention is not limited to these.
[0020]
The hydrogen peroxide concentrations in Examples 1 to 4 and Comparative Examples 1 to 2 were 0.02 mol / l potassium permanganate solution for volumetric analysis (manufactured by Wako Pure Chemical Industries, Ltd.) under sulfuric acid acidity (0.2N) conditions. ) At room temperature. For the titration, an automatic potentiometer AT-310 manufactured by Kyoto Electronics Industry Co., Ltd. was used.
[0021]
The hydrogen peroxide concentrations in Examples 5 to 15 and Comparative Example 3 were obtained by adding potassium iodide (manufactured by Wako Pure Chemical Industries, Ltd.) excessively under sulfuric acid acidity (0.2N) conditions, and analyzing the volume of free iodine. It was determined at room temperature by a titration method using a 0.1 mol / 1 sodium thiosulfate solution (manufactured by Wako Pure Chemical Industries, Ltd.). For the titration, an automatic potentiometer AT-310 manufactured by Kyoto Electronics Industry Co., Ltd. was used.
[0022]
The specific surface area was measured by using Flowsorb II2300 manufactured by Micromeritics.
[0023]
Example 1
A 300-ml glass inner cylinder charged with 30 mg of PdBr ₂ (manufactured by Nacalai Tesque, Inc .: specific surface area 0.4 m ² / g) and 120 g of ion-exchanged water as a reaction medium was attached to an autoclave with an inner volume of 400 ml. Hydrogen gas was introduced at a rate of 80 ml / min and oxygen gas at a rate of 800 ml / min. For safety, nitrogen gas was introduced and diluted at 2500 ml / min in the gas phase. The pressure was maintained so that the internal pressure of the autoclave was 9 kg / cm ² · G, and the reaction solution was kept at 20 ° C. by external cooling.
The hydrogen peroxide concentration in the reaction solution after 2 hours from the start of the reaction was 0.05 wt%. The amount of hydrogen peroxide produced per 1 mg of PdBr ₂ was 0.06 mmol.
[0024]
Comparative Example 1
The reaction was carried out under the same conditions as in Example 1 except that PdBr ₂ was changed to 30 mg of Pd powder (manufactured by Tanaka Kikinzoku Kogyo: specific surface area 10.8 m ² / g). The hydrogen peroxide concentration in the reaction solution 2 hours after the start of the reaction was below the detection limit (0.00 wt%).
[0025]
Example 2
The reaction was performed under the same conditions as in Example 1 except that the reaction medium was a mixture of 6 g of 1N—H ₂ SO ₄ aqueous solution and 114 g of ion-exchanged water. The hydrogen peroxide concentration in the reaction solution after 2 hours from the start of the reaction was 0.09 wt%. The amount of hydrogen peroxide produced per 1 mg of PdBr ₂ was 0.10 mmol.
[0026]
Comparative Example 2
The reaction was carried out under the same conditions as in Example 2 except that PdBr ₂ was changed to 30 mg Pd / C (manufactured by N.E. Chemcat Co., Ltd .: Pd content 5 wt%: specific surface area 800 m ² / g). The hydrogen peroxide concentration in the reaction solution 2 hours after the start of the reaction was below the detection limit (0.00 wt%).
[0027]
Example 3
The reaction was performed under the same conditions as in Example 1 except that PdBr ₂ was changed to 30 mg PdCl ₂ (manufactured by Wako Pure Chemical Industries, Ltd .: specific surface area 0.4 m ² / g). The hydrogen peroxide concentration in the reaction solution after 2 hours from the start of the reaction was 0.05 wt%. The amount of hydrogen peroxide produced per 1 mg of PdCl ₂ was 0.06 mmol.
[0028]
Example 4
The reaction was performed under the same conditions as in Example 1 except that PdBr ₂ was changed to 30 mg of Pd (NH ₃ ) ₂ Cl ₂ (manufactured by Aldrich). The hydrogen peroxide concentration in the reaction solution after 2 hours from the start of the reaction was 0.09 wt%. The amount of hydrogen peroxide produced per 1 mg of Pd (NH ₃ ) ₂ Cl ₂ was 0.10 mmol.
[0029]
Example 5
The reaction was carried out under the same conditions as in Example 1 except that the reaction medium was 120 ml of methanol. The hydrogen peroxide concentration in the reaction solution 2 hours after the start of the reaction was 0.15 wt%. The amount of hydrogen peroxide produced per 1 mg of PdBr ₂ was 0.12 mmol.
[0030]
Example 6
The reaction was performed under the same conditions as in Example 5, except that PdBr ₂ was changed to 30 mg PdCl ₂ (manufactured by Wako Pure Chemical Industries, Ltd .: specific surface area 0.4 m ² / g). The hydrogen peroxide concentration in the reaction solution 2 hours after the start of the reaction was 0.33 wt%. The amount of hydrogen peroxide produced per 1 mg of PdCl ₂ was 0.26 mmol.
[0031]
Example 7
The reaction was performed under the same conditions as in Example 5 except that PdBr ₂ was changed to 30 mg of PtBr ₂ (manufactured by Acros). The hydrogen peroxide concentration in the reaction solution 2 hours after the start of the reaction was 0.08 wt%. The amount of hydrogen peroxide produced per 1 mg of PtBr ₂ was 0.06 mmol.
[0032]
Example 8
The reaction was performed under the same conditions as in Example 5 except that PdBr ₂ was changed to 30 mg of PtCl ₂ (manufactured by Wako Pure Chemical Industries, Ltd.). The hydrogen peroxide concentration in the reaction solution after 2 hours from the start of the reaction was 0.02 wt%. The amount of hydrogen peroxide produced per 1 mg of PtCl ₂ was 0.02 mmol.
[0033]
Example 9
The reaction was performed under the same conditions as in Example 5 except that the reaction medium was a mixture of 60 ml of ion-exchanged water and 60 ml of methanol. The hydrogen peroxide concentration in the reaction solution after 2 hours from the start of the reaction was 0.06 wt%. The amount of hydrogen peroxide produced per 1 mg of PdBr _{2 was} 0.05 mmol.
[0034]
Example 10
The reaction was carried out under the same conditions as in Example 5 except that the reaction medium was a mixture of 18 ml of ion-exchanged water and 102 ml of methanol. The hydrogen peroxide concentration in the reaction solution after 2 hours from the start of the reaction was 0.11 wt%. The amount of hydrogen peroxide produced per 1 mg of PdBr ₂ was 0.10 mmol.
[0035]
Example 11
The reaction was carried out under the same conditions as in Example 5 except that the reaction medium was a mixture of 60 ml of methanol and 60 ml of n-octane. The hydrogen peroxide concentration in the methanol phase 2 hours after the start of the reaction was 0.39 wt%. The amount of hydrogen peroxide produced per 1 mg of PdBr ₂ was 0.15 mmol.
[0036]
Example 12
The reaction was carried out under the same conditions as in Example 5 except that the reaction medium was a mixture of 60 ml of ethylene glycol and 60 ml of n-octane. The hydrogen peroxide concentration in the ethylene glycol phase 2 hours after the start of the reaction was 0.07 wt%. The amount of hydrogen peroxide produced per 1 mg of PdBr ₂ was 0.04 mmol.
[0037]
Example 13
The reaction was performed under the same conditions as in Example 5 except that the reaction medium was 120 ml of ethanol. The hydrogen peroxide concentration in the reaction solution after 2 hours from the start of the reaction was 0.09 wt%. The amount of hydrogen peroxide produced per 1 mg of PdBr _{2 was} 0.07 mmol.
[0038]
Example 14
The reaction was performed under the same conditions as in Example 5 except that the reaction medium was 120 ml of isopropanol. The hydrogen peroxide concentration in the reaction solution after 2 hours from the start of the reaction was 0.03 wt%. The amount of hydrogen peroxide produced per 1 mg of PdBr ₂ was 0.02 mmol.
[0039]
Example 15
(1) a supported preparation of PdBr ₂ in the preparation titanosilicate carrying PdBr ₂ was carried out by the following method. That is, 50 mg of PdBr ₂ (manufactured by Nacalai Tesque Co., Ltd.) was dissolved in 1.5 g of hydrobromic acid (manufactured by Wako Pure Chemicals, 47.0-49.0%) and then diluted with 20 ml of ion-exchanged water. 1 g of silicate (manufactured by N.E. Chemcat Co., Ltd .: Si / Ti atomic ratio 100) was suspended. The suspension was stirred for 1 hour and then evaporated to dryness on a hot plate. After washing with ion-exchanged water and ethanol and filtering, it was dried in a dryer at 100 ° C. for 1 hour to obtain PdBr ₂ / titanosilicate (5 wt% -PdBr ₂ ).
[0040]
(2) the production PdBr ₂ of hydrogen peroxide, except that the PdBr ₂ / titanosilicate _(5wt% -PdBr 2) 30mg prepared in the above (1) The reaction was carried out under the same conditions as in Example 5 . The hydrogen peroxide concentration in the reaction solution after 2 hours from the start of the reaction was 0.06 wt%. The amount of hydrogen peroxide produced per 1 mg of PdBr ₂ / titanosilicate was 0.04 mmol, and the amount of hydrogen peroxide produced per 1 mg of PdBr ₂ was 0.83 mmol.
[0041]
Comparative Example 3
The reaction was carried out under the same conditions as in Example 5 except that PdBr ₂ was changed to 30 mg Pd / C (manufactured by N.E. Chemcat Co., Ltd .: Pd content 5%: specific surface area 800 m ² / g). The hydrogen peroxide concentration in the reaction solution 2 hours after the start of the reaction was below the detection limit (0.00 wt%).
【The invention's effect】
The method for producing hydrogen peroxide according to the present invention does not require a step of adding an acid or a halogen ion, and the reaction proceeds by using a compound with a small number of preparation steps, and the amount of hydrogen peroxide generated per compound is large. . As a result, it is possible to produce hydrogen peroxide in a much simplified process.

Claims (10)

A method for producing hydrogen peroxide, comprising reacting hydrogen and oxygen in a reaction medium containing a halogen compound of a platinum group metal and an alcohol . A method for producing hydrogen peroxide, characterized by reacting hydrogen and oxygen in a reaction medium containing a halogen compound of a platinum group metal and containing an alcohol . The method for producing hydrogen peroxide according to claim 1 or 2, wherein a platinum group metal halogen compound is supported on a carrier. The reaction medium containing alcohol is a mixed solution of water and alcohol (1 to 8 carbon atoms) or an alcohol (1 to 8 carbon atoms) alone. A method for producing hydrogen peroxide according to claim 1. The method for producing hydrogen peroxide according to any one of claims 1 to 3, wherein the reaction medium containing alcohol is alcohol (C1-8) alone. The reaction medium containing an alcohol is any one of methanol alone, a mixture of methanol and n-octane, a mixture of ethylene glycol and n-octane, or ethanol alone. Method for producing hydrogen peroxide. 4. The method for producing hydrogen peroxide according to claim 3, wherein the carrier is titanosilicate. The method for producing hydrogen peroxide according to any one of claims 1 to 7 , wherein the platinum group metal is palladium or platinum. The method for producing hydrogen peroxide according to any one of claims 1 to 7 , wherein the halogen compound of the platinum group metal is a chloride or bromide of either palladium or platinum. Method for producing hydrogen peroxide according to any one of claims 1 to 7, wherein the halogen compound of the platinum group metal is a chloride or bromide of palladium.