JPH06192150A - Production of aromatic hydroxy compound - Google Patents

Abstract

PURPOSE:To provide a method for producing an aromatic hydroxyl compound such as phenol from an aromatic compound such as benzene through one process. CONSTITUTION:An aromatic compound such as benzene is oxidized by using an oxidizing agent such as oxygen in the presence of a triarylphosphine as a catalyst. An aromatic compound as the raw material, e.g. benzene and oxygen are charged into a reactor and reacted in the presence of a triarylphosphine. Thereby, an aromatic hydroxy compound such as phenol can be produced. If an oxidizing agent such as oxygen is further added, the yield of phenol, etc., can be improved. This is a remarkably corrosion-resistant production method and further reduced in formation of by-products and excellent in economical efficiency.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a novel process for producing an aromatic hydroxy compound, which comprises producing at least one aromatic hydroxy compound from an aromatic compound in one step.

[0002]

2. Description of the Related Art Conventionally, as a method for producing phenol from benzene and oxygen in one step, a method of reacting benzene and oxygen in a gas phase or a liquid phase in the presence of a catalyst is known.
However, in the case of a gas phase reaction, complete oxidation of benzene occurs and the selectivity of phenol is very low (Japanese Patent Laid-Open No. 56-87).
527). In the case of the liquid phase reaction, there is a method of oxidizing benzene using copper salt and oxygen, but the conversion rate of benzene is low and the yield of phenol is low (organic synthetic chemistry 41,
839 (1983)).

Further, using a palladium-based catalyst, 1,1
Although there is a method of oxidizing benzene in the presence of 0-phenanthroline and carbon monoxide, the yield of phenol is low (JP-A-2-19809). Therefore, a method for producing phenol by direct oxidation of benzene has been desired,
It has not been industrialized yet.

Further, Japanese patent, Japanese Patent Laid-Open No. Hei 3-23633.
No. 8 discloses a method for producing phenol from benzene using a metal phosphate catalyst. According to this method, the yield of phenol is about 6%, which is an unprecedentedly high yield, but the reaction temperature is as high as about 500 ° C., and a sufficiently economical production method has not yet been reached.

[0005]

Therefore, an object of the present invention is to obtain a high yield of aromatic hydroxy compounds represented by phenols from aromatic compounds represented by benzene and benzene derivatives under mild and low corrosive conditions. Is to provide a method of manufacturing.

[0006]

Means for Solving the Problems As a result of intensive studies on the above problems, the present inventors have shown that aromatic compounds represented by benzene and benzene derivatives are represented by phenols and the like in the presence of an oxidizing agent such as oxygen. The present invention has been completed by finding a method for producing an aromatic hydroxy compound according to the present invention in a high yield under mild and low corrosive conditions. That is, the present invention is a method for producing an aromatic hydroxy compound, which comprises reacting an aromatic compound with an oxidizing agent in the presence of triarylphosphine. Further, the present invention is a method for producing an aromatic hydroxy compound, which comprises reacting an aromatic compound with an oxidizing agent in the presence of triphenylphosphine. As a result, by carrying out the present invention, a method for producing an aromatic hydroxy compound, which is extremely highly efficient, has low corrosiveness, and is excellent from the economical viewpoint, is provided.

The aromatic compound used in the present invention is a 6-carbon ring condensed compound such as benzene, substituted benzenes, naphthalene, substituted naphthalene, anthracene, substituted anthracenes, durene and substituted durenes, thiophene,
Substituted thiophenes, furans, substituted furans, pyridine,
Heteroaromatic compounds such as substituted pyridines, quinolines, and substituted quinolines. Substituents which these aromatic compounds have include alkyl groups such as methyl, ethyl, propyl and butyl groups, carboxyl groups, nitro groups, amino groups, cyano groups, acetyl groups, alkoxy groups, hydroxyl groups, acetoxy groups, halogens. Examples include elements and thioalkoxy groups. These are used alone or in combination of two or more. Specific examples of the substituted benzenes include toluene, ethylbenzene, xylene, propylbenzene, butylbenzene, benzoic acid, nitrobenzene, aniline, benzonitrile, acetophenone, anisole, phenol, catechol, resorcin, hydroquinone, phenyl acetate, fluorobenzene and chloro. Examples include benzene, bromobenzene, iodobenzene, and thioanisole.

The aromatic hydroxy compound produced by the method of the present invention is a compound in which at least one hydroxy group is directly bonded to the carbon forming the aromatic ring of the above-mentioned aromatic compounds, and more specifically, the above At least one carbon-hydrogen bond at the carbon forming the aromatic ring of the aromatic compound is converted into a carbon-hydroxy bond. For example, benzene produces phenol, catechol, hydroquinone, resorcin, etc., naphthalene produces naphthols, dihydroxynaphthalene, etc., toluene produces mono- and polyhydroxytoluenes, anisole produces methoxyphenol, methoxyresorcin, etc. Is generated. Similarly, a compound having one or more hydroxy groups directly bonded to aromatic carbon is produced from the aromatic compound. Depending on the reaction conditions,
Quinones such as benzoquinone, naphthoquinone or anthraquinone are also formed with aromatic hydroxy compounds at the same time.

Specific examples of the triarylphosphine used in the present invention include triphenylphosphine, tritolylphosphine, trixylylphosphine, tribiphenylylphosphine, trinaphthylphosphine, trianthrylphosphine and triphenanthrylphosphine. In the present invention, the amount of triarylphosphine used is not particularly limited, but in the case of triphenylphosphine, if an amount that is easy to carry out is given as an example, 100 g of aromatic compound used in a batch reaction is used. 0.001-500 g, more preferably 0.1-5
The amount is 0 g.

The oxidant used in the present invention is a substance capable of supplying oxygen molecules, oxygen atoms, oxygen ions or oxygen radicals in the reaction state in the reaction system. Specifically, oxygen gas, oxygen gas diluted with an inert gas,
Air, diluted air, hydrogen peroxide, organic peroxides, inorganic peroxides, etc. are exemplified, and one or more of these are used.

In the present invention, the yield of an aromatic hydroxy compound such as phenol can be improved by allowing water to exist in the reaction system in a gas or liquid state.
The amount of water used is not particularly limited, but is 0.001 to 500 g, and more preferably 0.1 to 50 g with respect to 100 g of the aromatic compound. Further, the reaction system is preferably acidic. This acidity is achieved by adding an acidic substance to the reaction system. The amount added is not particularly limited, but when it is carried out in the liquid phase, it is preferably an amount such that the pH of the reaction liquid becomes 1 to 5. Examples of the acidic substance added to the reaction system include Bronsted acid and Lewis acid. Examples of the Bronsted acid include mineral acids such as heteropoly acid, hydrochloric acid, sulfuric acid, nitric acid, phosphoric acid and boric acid, organic acids such as acetic acid, benzoic acid, formic acid, trichloroacetic acid, trifluoromethanesulfonic acid and sulfonic acid, and zeolites. Inorganic acids such as mixed oxides.
Examples of Lewis acids include aluminum chloride, ferric chloride, boron chloride compounds, antimony chloride compounds, stannic chloride, antimony fluoride, zeolites and mixed oxides. Furthermore, inorganic and organic acid salts are also used as the acidic substance.

The heteropolyacid used in the present invention is generally a composite metal oxide acid composed of two or more different metal oxide composites and those in which some or all of the protons of these acids are replaced with metal cations. Is. As a preferable heteropoly acid, a heteropoly acid containing vanadium as a hetero atom as a metal is recommended, and as a more easily available heteropoly acid, a general formula H _{(3 + n)} PV _n Mo is used.
_(12-n) O ₄₀ , H _{(4 + n)} SiV _n Mo _(12-n) O ₄₀ , H _{(3 + n)}
PV _n W _(12-n) O ₄₀ , H _{(4 + n)} SiV _n W _(12-n) O ₄₀ (where n is a positive integer of 0 or 6 or less, H is a hydrogen atom, and P is Phosphorus atom, Si is a silicon atom, V is a vanadium atom, Mo is a molybdenum atom, W is a tungsten atom, and O is an oxygen atom.) And a part or all of the protons of these heteropolyacids. Heteropolyacids exchanged with metal ions are exemplified as easily available.

The metal to be exchanged with the proton of the heteropoly acid in the method of the present invention may be a metal ion of a typical metal or a transition metal, but is preferably an ion of a typical metal, more preferably an alkali metal or an alkaline earth metal. It is a heteropoly acid in which at least one kind of metal ion is exchanged. The method of exchanging a proton with a metal ion is not particularly limited in the method of the present invention, and any method may be used as long as a substantially metal ion-exchanged form is obtained, but a method that is easy to carry out As an example, there may be mentioned a method in which an aqueous solution of a metal hydroxide, a metal carbonate, a metal acetate or the like and an aqueous solution of a heteropolyacid are stirred and mixed, and then isolated by evaporation to dryness.

A specific example of the heteropolyacid in the method of the present invention is H ₄ PVMo in terms of molecular formula or rational formula.
_{11 O4 0, H 5 PV 2} Mo 10 O 40, H 6 PV 3 Mo 9 O 40, H 7 PV 4 Mo 8 O 40, H 8 P
V ₅ Mo ₇ O ₄₀ , NaH ₃ PVMo ₁₁ O ₄₀ , Na ₂ H ₂ PVMo ₁₁ O ₄₀ , Na ₃ HPVMo
₁₁ O ₄₀ , Na ₄ PVMo ₁₁ O ₄₀ , KH ₃ PVMo ₁₁ O ₄₀ , K ₂ H ₂ PVMo ₁₁ O ₄₀ ,
K ₃ HPVMo ₁₁ O ₄₀ , K ₄ PVMo ₁₁ O ₄₀ , LiH ₃ PVMo ₁₁ O ₄₀ , Li ₂ H ₂ PVM
o ₁₁ O ₄₀ , Li ₃ HPVMo ₁₁ O ₄₀ , Li ₄ PVMo ₁₁ O ₄₀ , RbH ₃ PVMo
₁₁ O ₄₀ , Rb ₂ H ₂ PVMo ₁₁ O ₄₀ , Rb ₃ HPVMo ₁₁ O ₄₀ , Rb ₄ PVMo
₁₁ O ₄₀ , CsH ₃ PVMo ₁₁ O ₄₀ , Cs ₂ H ₂ PVMo ₁₁ O ₄₀ , Cs ₃ HPVMo ₁₁ O
₄₀ , Cs ₄ PVMo ₁₁ O ₄₀ , MgH ₃ PVMo ₁₁ O ₄₀ , Mg ₂ H ₂ PVMo ₁₁ O ₄₀ , M
g ₃ HPVMo ₁₁ O ₄₀ , Mg ₄ PVMo ₁₁ O ₄₀ , CaH ₃ PVMo ₁₁ O ₄₀ , Ca ₂ H ₂ PV
Mo ₁₁ O ₄₀ , Ca ₃ HPVMo ₁₁ O ₄₀ , Ca ₄ PVMo ₁₁ O ₄₀ , NaH ₄ PV ₂ Mo ₁₀ O
₄₀ , Na ₂ H ₃ PV ₂ Mo ₁₀ O ₄₀ , Na ₂ H ₃ PV ₂ Mo ₁₀ O ₄₀ , Na ₃ H ₂ PV ₂ Mo ₁₀
O ₄₀ , Na ₄ HPV ₂ Mo ₁₀ O ₄₀ , Na ₅ PV ₂ Mo ₁₀ O ₄₀ , KH ₄ PV ₂ Mo
₁₀ O ₄₀ , K ₂ H ₃ PV ₂ Mo ₁₀ O ₄₀ , K ₂ H ₃ PV ₂ Mo ₁₀ O ₄₀ , K ₃ H ₂ PV ₂ Mo ₁₀
O ₄₀ , K ₄ HPV ₂ Mo ₁₀ O ₄₀ , K ₅ PV ₂ Mo ₁₀ O ₄₀ , LiH ₄ PV ₂ Mo ₁₀ O ₄₀ ,
Li ₂ H ₃ PV ₂ Mo ₁₀ O ₄₀ , Li ₂ H ₃ PV ₂ Mo ₁₀ O ₄₀ , Li ₃ H ₂ PV ₂ Mo
₁₀ O ₄₀ , Li ₄ HPV ₂ Mo ₁₀ O ₄₀ , Li ₅ PV ₂ Mo ₁₀ O ₄₀ , RbH ₄ PV ₂ Mo ₁₀ O
₄₀ , Rb ₂ H ₃ PV ₂ Mo ₁₀ O ₄₀ , Rb ₂ H ₃ PV ₂ Mo ₁₀ O ₄₀ , Rb ₃ H ₂ PV ₂ Mo ₁₀
O ₄₀ , Rb ₄ HPV ₂ Mo ₁₀ O ₄₀ , Rb ₅ PV ₂ Mo ₁₀ O ₄₀ , CsH ₄ PV ₂ Mo
₁₀ O ₄₀ , Cs ₂ H ₃ PV ₂ Mo ₁₀ O ₄₀ , CsRb ₂ H ₃ PV ₂ Mo ₁₀ O ₄₀ , Cs ₃ H ₂ PV
₂ Mo ₁₀ O ₄₀ , Cs ₄ HPV ₂ Mo ₁₀ O ₄₀ , Cs ₅ PV ₂ Mo ₁₀ O ₄₀ , etc.

When the method of the present invention is carried out in the liquid phase, the reaction solution is usually used at a pH of 7 or less, preferably a pH of 5 or less to 1 or more. However, the method of the present invention is not necessarily limited to these ranges.

In carrying out the method of the present invention, it is also possible to add a solvent or gas which is inactive to the catalyst and the reaction reagent into the reaction system and carry out the reaction in a diluted state.
Specific examples thereof include aliphatic saturated hydrocarbons such as methane, ethane, propane, butane, hexane and cyclohexane, and inert gases such as nitrogen, argon and helium.

The reaction temperature is not particularly limited, but is preferably 0 to 400 ° C, more preferably 10 to 300 ° C. If the reaction temperature is extremely low, the conversion rate of the aromatic compound (reaction reagent) is low, in other words, the reaction rate is extremely low, and the productivity of the reaction product is low. On the other hand, when the reaction temperature is 400 ° C. or higher, undesirable side reactions and the like progress to increase by-products, and the stability of the aromatic compound as a raw material and the aromatic hydroxy compound as a product is also preferable. In addition, the reaction selectivity is lowered, which is not economical.

The reaction can be carried out under any of reduced pressure, increased pressure and normal pressure. From the viewpoint of reaction efficiency (reaction efficiency per unit volume), it is not preferable to carry out at a too low pressure. In addition, it is not preferable to carry out the reaction at an excessively high pressure from the viewpoint of the economical efficiency of the equipment such as a reactor.
Generally preferred operating pressure range is 0.05 to 300 atmospheres, more preferably 0.5 to 200 atmospheres. However, the invention is not limited to only these pressure ranges.

The reaction can be carried out in any of a liquid phase, a gas-liquid phase and a gas phase. Furthermore, the catalyst can be used in either a uniform or non-uniform form.
These catalysts can be used in any of a solution state, a two-layer separated state, a two-layer mixed layer state, a slurry state, a fixed bed, a moving bed, a fluidized bed and the like.

The method of the present invention can be carried out in any reaction method such as a normal batch reaction, a semi-batch reaction in which a part of raw materials or catalysts are continuously supplied, or a continuous flow reaction. Further, the addition order and addition method of each component such as the reaction raw material, the oxidizing substance, and the catalyst are not particularly limited.

Further, it is also possible to carry out in a semi-batch form such that an oxidizing agent such as oxygen is sequentially added several times depending on the consumption thereof (that is, intermittent insertion), whereby phenol can be used. In some cases, the yield of the aromatic hydroxy compound such as is improved.

The reaction time (residence time or catalyst contact time in flow reaction) is not particularly limited, but is usually 0.
It is 1 second to 30 hours, preferably 0.5 seconds to 15 hours. After the reaction, if necessary, the reaction product can be separated and recovered from the catalyst or the like by a method such as filtration separation, extraction, and distillation. The aromatic hydroxy compound which is the target product is a sequential treatment method such as solvent extraction, distillation, alkali treatment, acid treatment or the like from the above separated and recovered material, or an ordinary separation or purification method such as an operation in which these are appropriately combined. Can be separated, purified, and obtained. Further, the unreacted raw material can be recovered and recycled to the reaction system for use.

In the case of a batch type reaction, the catalyst recovered by separating the reaction product after the reaction may be used as it is, or after regenerating a part or all thereof, it may be repeatedly used as a catalyst in the reaction again. When carried out in a fixed bed or fluidized bed flow continuous reaction system, by subjecting it to the reaction, a part or all of the catalyst is deactivated or activity-reduced,
After the reaction is interrupted, it can be regenerated and used for the reaction, or a part of the catalyst can be continuously or intermittently withdrawn, regenerated and recycled to the reactor for reuse. Further, fresh catalyst can be continuously or intermittently fed to the reactor. When the reaction is carried out in a moving bed flow continuous reaction or a homogeneous catalyst flow reaction system, the catalyst can be separated, regenerated and reused as in the batch reaction.

[0024]

EXAMPLES The method of the present invention will be described in more detail below with reference to examples. However, the method of the present invention is not limited to these examples. The yield of the hydroxy compound, which is the product described in each of the examples and the table, was based on the charged aromatic compound.

Example 1 Benzene was added to 50 ml of Hastelloy C autoclave.
After charging 15.0 g, water 15.0 g, triphenylphosphine, and 0.53 g, the inside of this autoclave was replaced with a mixed gas of oxygen 9% and nitrogen 91%, and then pressure was further increased to 110 kg / cm ₂ . The reaction temperature was 180 ° C and the reaction was carried out for 1.0 hour with stirring, then cooled, methanol was added to the reaction solution to homogenize it, and the result was analyzed by gas chromatography. As a result, phenol was produced in a yield of 3.1% based on the charged benzene. It was confirmed that

Example 2 In the method carried out in Example 1, H ₇ PV ₄ M was added to the reaction solution.
o ₈ O ₄₀ · 30H ₂ O, all under the same conditions and methods as in Example 1 except that 0.42 g was added. As a result, the phenol yield was 4.0%.

Example 3 Reaction and analysis were carried out under the same conditions and methods as in Example 2, except that H ₆ PV ₃ Mo ₉ O ₄₀ · 30H ₂ O (0.42 g) was used as the heteropolyacid. As a result, the yield of phenol was 3.8%.

Example 4 The reaction and analysis were carried out under the same conditions as in Example 2 except that the heteropolyacid was replaced by H ₅ PV ₂ Mo ₁₀ O ₄₀ · 30H ₂ O, 0.42 g. As a result, the yield of phenol was 3.5%.

Example 5 The reaction and analysis were carried out under the same conditions as in Example 2 except that the heteropolyacid was Na ₃ H ₃ PV ₃ Mo ₉ O ₄₀ , 0.42 g. The result was a phenol yield of 3.4%.

Example 6 The reaction and analysis were carried out under the same conditions as in Example 1 except that 5.0 g of 0.1 N sulfuric acid was used instead of water in the method carried out in Example 1. As a result, the yield of phenol is 3.3%
Met.

Example 7 The procedure of Example 1 was repeated except that 0.1N phosphoric acid was used instead of water.
The reaction and analysis were conducted under the same conditions as in Example 1 except that 0 g was used. As a result, the yield of phenol was 3.5%.

Example 8 The procedure of Example 1 was repeated except that the water in the reaction solution was omitted. As a result, the phenol yield was 2.3%.

Examples 9 to 11 In the method carried out in Example 1, the reaction temperature was 10
Table 1 shows the results obtained under the same conditions and methods as in Example 1 except that 0, 125, and 150 ° C were used. The results of Example 1 are also shown.

[0034]

[Table 1] Table 1 ──────────────────────────────────── Reaction temperature (℃) Phenol yield (%) ──────────────────────────────────── Example 9 100 A trace amount Example 10 125 A trace amount Example 11 150 1.0 Example 1 180 3.1 ─────────────────────────────────────

Examples 12 to 17 All the same as Example 1 except that toluene, phenol, naphthalene, β-naphthol, anisole and p-xylene were each replaced by 15.0 g instead of benzene. Reaction and analysis were carried out under the conditions and methods. As a result, as shown in Table 2, the production of aromatic hydroxy compounds was recognized in good yields. The aromatic dihydroxy compound in the product is shown as the total of all isomers.

[0036]

[Table 2] Table 2 ──────────────────────────────────── Aromatic compound Yield (%) Hydroxy Compound Dihydroxy Compound ──────────────────────────────────── Example 12 Toluene 2.3 0.1 Example 13 Phenol (raw material) 1.1 Example 14 Naphthalene 1.6 0.1 Example 15 β-naphthol (raw material) 0.4 Example 16 Anisole 1.4 0.1 Example 17 p-xylene 2. 6 Trace amount ─────────────────────────────────────

[0037]

According to the present invention, the following effects can be obtained. (1) Phenol can be produced with high selectivity by directly oxidizing benzene. (2) Phenol can be directly oxidized and produced under mild conditions of low temperature and low pressure as compared with the conventional method. In addition, it can be carried out under the condition that the reactor or the like is hardly corroded. (3) In terms of safety, process, and phenol, which are industrially important,
It is possible to produce a significant economic advantage. As described above, the present invention can provide a novel industrially excellent method for producing phenol.

Continuation of the front page (51) Int.Cl. ⁵ Identification code Office reference number FI technical display location C07C 39/14 8930-4H // C07B 61/00 300

Claims (8)

[Claims] 1. A method for producing an aromatic hydroxy compound, which comprises reacting an aromatic compound with an oxidizing agent in the presence of triarylphosphine. 2. The method according to claim 1, wherein the triarylphosphine is triphenylphosphine. 3. The oxidant is a substance capable of supplying an oxygen molecule, an oxygen atom, an oxygen ion or an oxygen radical.
Or the method described in 2. 4. The method according to claim 1, wherein the oxidant is oxygen gas or oxygen gas diluted with an inert gas. 5. The method according to claim 1, wherein the reaction is carried out in the presence of water. 6. The method according to claim 1, wherein the reaction is carried out in the presence of an acid. 7. The method of claim 6, wherein the acid is a heteropoly acid. 8. The method according to claim 1, wherein the oxidizing agent is intermittently inserted.