JPH04364144A - Production of partially oxide of aromatic compound - Google Patents

Abstract

PURPOSE:To provide a method for producing phenols with ultrahigh economical efficiency by partial oxidation of aromatic compounds in which low selectivity in conventional direct oxidative reaction with oxygen is improved and electric power, as necessary, is taken out to the outside of the reactional system by using a fuel cell system. CONSTITUTION:The subject method is to produce a partial oxide of an aromatic compound as follows. A proton conductor membrane is used and a catalyst electrode composed of a metal and/or its compound is used as a positive pole. An electrode composed of a carbonaceous conductor presubjected to oxidation treatment with nitric acid, sulfuric acid, air heating, permanganic acid, etc., and a metal or its compound is employed as a negative pole to introduce hydrogen into the positive pole compartment and oxygen and benzene into the negative pole compartment. Both electrodes are then short-circuited with a lead wire to advance fuel cell reaction.

Description

[Detailed description of the invention]

0001

[Industrial Field of Application] Partial oxides of aromatic compounds such as phenol are raw materials for resins, etc., and are extremely important intermediate raw materials in the organic industry field. The present invention relates to a method for producing partial oxides such as phenols and quinones from aromatic compounds and oxygen using a fuel cell system using an ionic conductor provided with a catalyst electrode, and at the same time extracting electrical energy as necessary.

0002

BACKGROUND OF THE INVENTION Various methods are known for producing monovalent or polyvalent phenols and quinones such as benzoquinone from aromatic compounds. For example, phenols have conventionally been mainly produced by methods such as the cumene method, benzoic acid method, chlorobenzene method, and sulfonic acid method (see, for example, Journal of Japan Organic Synthesis Association, Vol. 35, No. 2, p. 138). All of these methods require complex reaction operations spanning several steps. In addition, it has disadvantages such as consuming expensive auxiliary raw materials. It is desirable from an industrial point of view to develop a process for producing phenol by direct oxygen oxidation of aromatic compounds and a single reaction operation, without consuming expensive auxiliary materials or producing co-products. Although various proposals have been made,
Both methods have low yields, harsh reaction conditions, or complicated reaction methods, and therefore cannot be implemented industrially. For example, JP-A-62-5
No. 4291 describes a method for obtaining phenol by oxidizing benzene with oxygen in the gas phase using a metal phosphate as a catalyst, but the process involves a high temperature of 500-600°C and a low yield.

Furthermore, JP-A No. 62-293738 discloses a method for obtaining phenol by oxidizing benzene with oxygen in the presence of carbon monoxide in a liquid phase in an acetic acid solvent using a palladium-based catalyst and 1,10-phenanthroline as additives. However, the yield is as low as 6%. Also, the Chemical Society of Japan 56th Spring Annual Meeting 2
In IID12, phenol is obtained by reacting benzene and oxygen using palladium supported on silica gel and copper sulfate as catalysts, but the yield is extremely low at 0.02% based on benzene, and furthermore, this method requires oxidation by oxygen. It is difficult to use as an industrial production method because of the complexity of having to perform the reaction and reduction treatment with hydrogen to regenerate the catalyst alternately, and the risk of explosion due to the mixture of hydrogen and oxygen. be.

On the other hand, attempts have been made to use fuel cell systems to produce various useful compounds and at the same time extract electric current, but there are no methods for producing partial oxides of aromatic compounds such as phenols and quinones. , patent application Hei 1-261
No. 493, other than the inventor's invention, is hitherto known.

[0005]

[Problems to be Solved by the Invention] The present invention uses a fuel cell system to selectively produce corresponding partial oxides such as phenols and quinones from aromatic compounds and oxygen in a single reaction operation. It solves the problems of conventional manufacturing methods, such as the complexity of the manufacturing process, the generation of large amounts of by-products, the large consumption of energy, and the risk of explosion.In addition, it can be carried out under extremely mild conditions, and if necessary, it can be done without electricity. The aim is to improve economic efficiency by allowing the production of other materials at the same time.

[0006] The object of the present invention is to use a fuel cell system to generate the above-mentioned aromatic compounds by contacting a hydrogen donor such as hydrogen with one electrode and an aromatic compound and oxygen with the other electrode of an ionic conductor provided with a catalytic electrode. The purpose of this invention is to produce partial oxides of aromatic compounds by simultaneously obtaining the corresponding partial oxides of aromatic compounds and extracting electrical energy as needed. As a result, when preparing a catalytic electrode that is brought into contact with oxygen and an aromatic compound, a carbonaceous material is used as the conductive material, and by oxidizing the carbonaceous conductive material in advance, aromatic compounds can be produced with extremely high efficiency. The present invention has been completed by making it possible to produce partial oxides of group compounds.

[0007]

The aromatic compound used in the method of the present invention is a substituted or unsubstituted aromatic hydrocarbon. For example, benzene, toluene, xylene, naphthalene, anthracene, and their derivatives, and the substituents that they may have include alkyl groups, aryl groups, aryloxy groups, sulfone groups, alkoxy groups, sulfone groups, and halogen groups. Examples include atoms.

The oxygen used in the process of the invention does not necessarily have to be pure, but may be a mixture with air or other inert gases. In addition, in the method of the present invention,
If necessary, it is also possible to extract electrical energy corresponding to the free energy of the reaction from the reaction system. FIG. 1 shows a conceptual diagram of a fuel cell type reactor used to carry out the method of the present invention.

An anode chamber 3 and a cathode chamber 4 having an anode 1 or a cathode 2 formed of a catalyst electrode are separated by an ion conductor 5, and the anode and cathode are short-circuited by a lead wire 6. The catalyst electrode is preferably porous or sheet-like, but is not necessarily limited thereto. 7 is a stirrer. If necessary, it is also possible to apply a voltage between the anode and the cathode.

Various materials can be used for the catalytic electrode used in the method of the present invention, but in the method of the present invention, it is especially recommended to use at least one of various metals or compounds thereof. Preferably, at least one metal or metal compound is mixed with or supported on an electrically conductive material. In addition, in order to further facilitate the implementation of the method of the present invention, it is preferable to use an electrode molded using a binder in addition to these constituent components.
However, the method of the present invention is not limited to only these methods. As the conductive polymer material used in the present invention, it is generally preferable to use a carbonaceous material such as graphite because of its low cost, easy availability, and good electrical conductivity. Furthermore, the conductive carbonaceous material used for the cathode may be any carbonaceous material as long as it has electrical conductivity, and may also be one that exhibits electrical conductivity through oxidation treatment. Specifically, graphite, activated carbon, carbon whiskers, and the like are listed as easily available.

[0011]Although various binders can be used for forming the electrode, hot press molding using Teflon resin powder is preferable because of its ease of molding. However, it goes without saying that the present invention is not limited to these materials and methods.

Next, the oxidation treatment of carbonaceous materials will be described. The oxidation treatment can be performed by various methods such as heat treatment using a normal oxygen-containing gas and reagent oxidation treatment using an oxidizing reagent. Examples of the reagent oxidation treatment include nitric acid water heat treatment, sulfuric acid water heat treatment, permanganic acid aqueous solution treatment, dichromic acid aqueous solution treatment, and hydrogen peroxide water treatment. However, the method of the present invention is not limited to only these treatments.

What is the periodic table meant by the method of the present invention? International Union of Pure and Applied Chemistry Nomenclature of Inorganic Chemistry Revised Edition (1989
The method of the present invention is carried out using at least one metal or metal compound as a catalyst electrode, and the metals constituting these metals or metal compounds are based on this periodic table. In the table of laws,
Group 3, Group 4, Group 5, Group 6, Group 7, Group 8, Group 9, Group 10,
Group 11 and Group 12 metals.

Specifically, the group 3 metal has the element symbol S
It is a metal represented by c, La, Y, Ac, etc.; group 4 metals are metals represented by element symbols Ti, Zr, Hf, and group 5 metals are metals represented by element symbols V, Nb, Ta. Group 6 metals include element symbols Cr, M
metals represented by o, W; group 7 metals are metals represented by element symbols Mn and Re; group 8 metals are metals represented by element symbols Fe, Ru, Os; 9
Group metals include metals with element symbols Co, Rh, and Ir, and Group 10 metals include element symbols Ni, Pd,
It is a metal represented by Pt, and group 11 metals are metals represented by element symbols Cu, Ag, and Au, and group 12 metals are metals represented by element symbols Zn, Cd, and Hg. Furthermore, when these metals are used as compounds in the anode in the method of the present invention, they may be used as halides, nitrates, sulfates, oxides, hydroxides, phosphates and/or ammonium salts of these metals. It is recommended that In the method of the present invention, an electrode is prepared using at least one of these metals or metal compounds. The ionic conductors used in the method of the present invention include protonic acids such as phosphoric acid, sulfuric acid, and hydrochloric acid, heteropolyacids, solid electrolytes known as proton conductors such as H-montmorillonite, and zirconium phosphate, and SrCeO3 as a matrix. A perovskite solid solution or the like can be used. In addition, products based on fluorine-containing polymers such as perfluorocarbons and into which one or more types of cation exchange groups such as sulfone groups or carboxylic acid groups are introduced, such as Nafion.
(registered trademark of DuPont) can also be used. A liquid such as phosphoric acid can be used by impregnating silica wool, or it can be used by sandwiching it between an ion-permeable filter or membrane.

The hydrogen donor used in the method of the present invention generally refers to a substance that can be oxidized by an anode electrode to generate protons (hydrogen cations). Specific examples include hydrogen molecules, alcohols, hydroquinones, and saturated hydrocarbons.

The hydrogen donor supplied as a raw material to the anode chamber is usually supplied as a gas or liquid, but if necessary, it may be dissolved in an inert medium or water and brought into contact with the electrode in a liquid phase. It may also be used as a mixture with an inert gas such as nitrogen, helium, or argon. The aromatic compound supplied to the cathode chamber is also supplied in a gaseous or liquid state, but oxygen or an oxygen-containing substance can also be used in a gaseous state or further diluted with a suitable solvent or gas. Moreover, it can also be used by dissolving or suspending it in a polar medium such as water. It is desirable that the cathode chamber be vigorously stirred in order to allow the reaction to proceed smoothly, in other words to ensure effective contact with the catalyst electrode. The reaction temperature is usually -20°C to 20°C.
Although it is carried out at 0°C, it is more preferably carried out at -5°C to 150°C. Furthermore, according to the method of the present invention, the reaction is generally carried out at normal pressure, but it can also be carried out under increased pressure or reduced pressure if necessary. Partial oxides such as phenols and quinones, which are reaction products, can be separated and purified from the reaction product liquid by a method such as distillation to obtain a high-quality target product.

[0017]

EXAMPLES The method of the present invention will be explained in more detail below based on examples. However, these are illustrative and the method of the present invention is not limited to these examples. In addition, among the symbols written in this example, mF represents millifaradic, μmol represents micromoles, and PhOH represents phenol. The anode used in this example and comparative example was 20 mg of gold black powder and 70 mg of graphite powder.
A mixture of 5 mg of Teflon powder and 5 mg of Teflon powder was well mixed and formed into a sheet by hot pressing. For all hydrogen donors, argon:hydrogen=50:50 volume ratio gas was used, and this was changed to 2 in all Examples and Comparative Examples.
A flow rate of 0 ml/min was introduced. The reaction temperature and reaction time were 30° C. and 3 hours in all Examples and Comparative Examples.

Example 1 Oxidation treatment was carried out in the following manner. (a) Heat treatment The carbonaceous material was heated at 300° C. for 3 hours under air. (b) Nitric acid treatment A carbonaceous material was immersed in an 8N nitric acid aqueous solution, heated and boiled for 2 hours, and then thoroughly washed with pure water and dried. (c) Permanganic acid treatment The concentration of potassium permanganate is 0 in the 4N sulfuric acid aqueous solution.
．． Potassium permanganate was added to make a homogeneous solution at a concentration of 0.02 mol/L, and a carbonaceous material was immersed in it at room temperature for 6 mol/L.
After leaving it for a while, it was thoroughly washed with pure water and dried. (d) Sulfuric acid treatment A carbonaceous material was immersed in a 4N sulfuric acid aqueous solution, heated and boiled for 2 hours, and then thoroughly washed with pure water and dried.

Example 2 Disc-shaped silica wool (thickness 1.0 mm, diameter 21
mm) impregnated with 85% phosphoric acid aqueous solution was used as an ion conductor membrane, and as the anode and cathode, 50 mg of graphite powder, which had been previously treated with nitric acid, 5 mg of Teflon powder, and further graphite (as carbon atoms): dichloride. The molar ratio of the two irons was adjusted to 99.5:0.5, and this mixture was mixed well and molded using the hot press method in the same way as the anode.The cathode was used as the cathode. Installed diagram 1
Using the reactor shown in , add 50 ml of benzene to the cathode chamber.
After charging, a mixed gas of argon and hydrogen having the above composition and flow rate was introduced into the anode chamber. Oxygen was supplied to the cathode chamber at an inflow rate of 5 ml/min, and a partial oxidation reaction of benzene was performed using a closed circuit in which the anode and cathode were connected with conductive wires. As a result, 3.82 μMOL of phenol was produced, and a current of 220.5 μqF flowed during this time.

Comparative Example 1 A partial oxidation reaction of benzene was carried out under all other conditions as in Example 2, with the electrodes in an open circuit state (no connection between the two electrodes). As a result, the reaction did not proceed and no phenol was detected.

Comparative Example 2 A partial oxidation reaction of benzene was carried out under the same conditions as in Example 1 except that both hydrogen gas and steam gas were supplied to the cathode chamber. As a result, almost no phenol formation was observed.

Comparative Example 3 A partial oxidation reaction of benzene was carried out under the same conditions as in Example 2, except that the graphite used for the cathode was not treated with nitric acid. As a result, phenol is 2.01
μMOL was generated, and during this time only 71.6 μF of current flowed. This result shows that the oxidation treatment in the method of the present invention is effective.

Example 3 Graphite treated with nitric acid: samarium chloride = 99.
A partial oxidation reaction of benzene was carried out under the same conditions as in Example 2, except that a cathode was prepared and used in the same manner as in Example 2, with a molar ratio of 5:0.5. As shown in Table 1, phenol was produced in good yield.

Example 4 A partial oxidation reaction of benzene was carried out under the same conditions as in Example 3, except that the graphite used for the cathode was subjected to the heat treatment described above. The results are listed in Table 1. Example 5 A partial oxidation reaction of benzene was carried out under the same conditions as in Example 3, except that the graphite used for the cathode was treated with sulfuric acid. The results are listed in Table 1. Example 6 A partial oxidation reaction of benzene was carried out under the same conditions as in Example 3 except that the graphite used for the cathode was treated with permanganate as described above. The results are shown in Table 1.

Comparative Example 4 A partial oxidation reaction of wenzene was carried out under the same conditions as in Example 3, except that the graphite used for the cathode was not oxidized. As shown in Table 1, it was confirmed that when graphite without oxidation treatment was used, the amount of phenol produced and the amount of current generated were clearly reduced.

Example 7 Activated carbon (carbon base): ferric chloride = 99.5 instead of graphite and activated carbon treated with nitric acid.
A partial oxidation reaction of benzene was carried out under all the same conditions as in Example 2, except that a sheet electrode was used as the cathode in the same manner as in the above cathode preparation method so that the molar ratio was 0.5. . As a result, phenol was 17.9
5 μMOL was generated and at the same time a current of 872 μF was generated.

[0027]

[Table 1] ──────────────────────────
──────────
Current amount (μF) PhOH generation amount (μMO
L) ────────────────
──────────────────── Example 3 316.8
5.48
Example 4 100.7
3.57
Example 5 171.
3 3.71
Example 6
240.7
5.26
Comparative example 4 72.8
1.10
────────────────────
──────────────────

[0028]

Effects of the Invention: Compared to conventional complicated methods such as the cumene method and the benzoic acid method, the method of the present invention allows the production of phenols corresponding to the aromatic compounds as starting materials by a one-step method directly from aromatic compounds and oxygen. It is possible to produce partial oxides such as Furthermore, no other auxiliary raw materials are required, and large amounts of side reaction products are not produced. Furthermore, compared to previous attempts at direct oxidation using aromatic compounds and oxygen, the reaction can be carried out under extremely mild conditions, and there is no risk of explosion due to direct mixing of oxygen and hydrogen. Furthermore, electric energy can be extracted together with the product if necessary. In addition, it is possible to carry out the reaction without using an ionic medium such as water, or even without using an electrolyte, and an efficient catalytic reaction can be carried out in a simple and smaller reactor. It has many advantages.

[Brief explanation of drawings]

FIG. 1 is a conceptual diagram of a fuel cell type reactor.

[Figure 1] Conceptual diagram of fuel cell type reactor

[Explanation of symbols]

1 Catalyst electrode (anode) 2 Catalyst electrode (cathode) 3 Anode chamber 4 Cathode chamber 5 Ion conductor 6 Lead wire 7 Stirrer

Claims (9)

[Claims] 1. A hydrogen donor is brought into contact with one electrode of an ionic conductor provided with a catalyst electrode, and an aromatic compound and oxygen are brought into contact with the other electrode to produce a corresponding partial oxide of the aromatic compound using a fuel cell system. When obtaining, the electrode that is brought into contact with the aromatic compound and oxygen is an electrode made of a conductive carbonaceous material that has been previously oxidized and at least one metal component selected from metals and/or metal compounds. A method for producing a partial oxide of an aromatic compound, characterized by: 2. The method according to claim 1, wherein the catalytic electrode that contacts the hydrogen donor comprises at least one metal component selected from metals and/or metal compounds and a conductive polymer material. . 3. A claim characterized in that the catalyst electrode on the side brought into contact with the hydrogen donor is made of at least one metal component selected from metals and/or metal compounds and a carbonaceous material that has been previously oxidized. The method described in Section 1. 4. The constituent metals of the metal or metal compound constituting the catalytic electrode belong to Group 3, Group 4, Group 5, Group 6, Group 7, Group 8, Group 9, Group 10, Group 11, and 2. The method according to claim 1, wherein the metal is at least one group 12 metal or a compound thereof. [Claim 5]Claim 1, wherein the hydrogen donor is a hydrogen molecule.
Method described. 6. The method according to claim 1, wherein the oxidation treatment is heat treatment of the carbonaceous material in the presence of an oxygen-containing gas. [Claim 7] The oxidation treatment is performed by heating the carbonaceous material in at least one solution selected from a permanganate solution, a nitric acid solution, a dichromate solution, and a sulfuric acid solution, or by contacting or leaving it at room temperature. The method according to claim 1. 8. The method according to claim 6, wherein the oxygen-containing gas is air. 9. Claim 7, wherein the permanganate solution, nitric acid solution, dichromate solution and sulfuric acid solution are each aqueous solutions.
Method described.