JP2795471B2 - Method for producing polyhydric phenols - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for efficiently producing a polyhydric phenol such as resorcin.

BACKGROUND OF THE INVENTION AND PROBLEMS OF THE INVENTION When an aromatic compound having an alkyl group, such as diisopropylbenzene, is oxidized with molecular oxygen in the presence of a base, diisopropylbenzene dihydroxy peroxide (hereinafter sometimes referred to as "DHP"), diisopropyl Benzene monocarbinol monohydroperoxide (hereinafter sometimes referred to as "HHP") and diisopropylbenzene monohydroperoxide (hereinafter "MHP")
It has been already known that various hydroperoxides such as, for example, dihydrobenzene and carbinols such as diisopropylbenzene dicarbinol (hereinafter, also referred to as “DC”) may be produced. Of these oxidation products, DHP can be acid-decomposed in an organic solvent to produce industrially highly useful resorcinol or hydroquinone.

In order to efficiently produce a polyhydric phenol such as resorcin using the above method, it is desirable that the concentration of DHP in the oxide serving as the acid decomposition raw material is high.

Therefore, a method of oxidizing HHP or DC to DHP by oxidizing an aromatic compound having an alkyl group with molecular oxygen as described above with molecular oxygen, and further oxidizing with hydrogen peroxide, followed by acid decomposition. [For example, British Patent No. 910735, JP-A-53-23939, JP-A-55-53265, filed on October 31, 1988 (Japanese Patent Application No.
3-275384)).

In the method using hydrogen peroxide as described above, an oxide obtained by oxidizing an aromatic compound having an alkyl group with molecular oxygen is transferred to an organic solvent, and then oxidized again using hydrogen peroxide. doing. In such a conventional method, it is considered that the oxide migrated into the organic solvent needs to contain a small amount of water in order to safely perform reoxidation using hydrogen peroxide. In general, the water content in the organic solvent to which the oxide has been transferred is generally adjusted to 3% or more, and this water content is considered to have a special effect on the yield of DHP. I didn't.

However, when the present inventors studied a method for improving the yield of polyhydric phenol, the water content in the organic solvent to which the oxide was transferred, which was conventionally considered to be not particularly related to the yield, was considered. The rate has been found to have a great effect on the yield of DHP. That is, a solution obtained by dissolving an oxide obtained by oxidizing an aromatic compound having an alkyl group with molecular oxygen in a conventional method in an organic solvent usually contains about 3% by weight of water, This level of water is DH
It does not adversely affect the production of P, and conversely, some water is said to be necessary for safe reoxidation with hydrogen peroxide. In addition, since this water is usually removed by azeotropic distillation, it is considered that there is no advantage from the industrial viewpoint to reduce the water content to less than this, for example, 1.5% by weight.

From such a technical background, in the prior art, DH
The yield of P is limited to about 90 mol% even if the best conditions are set, and it was thought that this yield could not be significantly increased.

This tendency is the same not only in the production of dihydric phenols, but also in the production of trihydric phenols such as phloroglucin and other polyhydric phenols.

OBJECTS OF THE INVENTION An object of the present invention is to provide a method for producing a polyhydric phenol in a method for producing a polyhydric phenol as described above, which can produce the polyhydric phenol in a higher yield.

SUMMARY OF THE INVENTION The method for producing polyhydric phenols according to the present invention comprises dissolving an oxidized aromatic compound having an alkyl group in an organic solvent, which is obtained by oxidizing an aromatic compound having an alkyl group with molecular oxygen. And then re-oxidized with hydrogen peroxide to produce an aromatic hydroperoxide compound from the aromatic carbinols.Then, when the aromatic hydroperoxide compound is acid-decomposed to produce a polyhydric phenol, The content of water contained in the organic solvent solution in which the aromatic compound having the alkyl group is dissolved is 1.
It is characterized in that it is reoxidized with hydrogen peroxide at not more than 09% by weight.

ADVANTAGE OF THE INVENTION According to this invention, since the water content of the organic solvent solution of the oxide reoxidized with hydrogen peroxide is low, DHP can be obtained in a still higher yield compared with the conventional method.

Next, the method for producing a polyhydric phenol according to the present invention will be specifically described.

Polyhydric phenols produced by the method of the present invention include dihydric phenols such as resorcinol and hydroquinone, trihydric phenols such as phloroglucin, and other polyhydric phenols having a valency of 4 or more.

The method for producing polyhydric phenols of the present invention can be employed when producing the above-mentioned polyhydric phenols. However, dihydric phenols and trihydric phenols can be advantageously produced, particularly dihydric phenols. Particularly suitable for the production of phenol. Hereinafter, the present invention will be described with reference to the production of dihydric phenol, particularly resorcinol.

In the present invention, as the aromatic compound having an alkyl group, an aromatic compound having a number of alkyl groups corresponding to the number of -OH groups of the polyhydric phenol to be obtained is used. The number of alkyl groups is usually 2-5, preferably 2-4.
Has carbon atoms.

Therefore, for example, when trying to obtain resorcinol,
Use is made of m-dialkylbenzene, especially m-diisopropylbenzene. Further, for example, when hydroquinone is to be obtained, p-dialkylbenzene, particularly p-dialkylbenzene
Use diisopropylbenzene. Furthermore, for example, when phloroglucin is to be obtained, 1,3,5-trialkylbenzene, especially 1,3,5-triisopropylbenzene, is used. When another polyhydric phenol is to be obtained, the corresponding alkylbenzene is selected and used according to the above case. As such other alkylbenzenes, when trying to obtain orcinol,
5-Diisopropyltoluene can be mentioned. In particular, in the present invention, the alkyl group is preferably an isopropyl group.

The aromatic compound having an alkyl group used in the present invention may have a substituent other than the alkyl group as long as the progress of the reaction is not excluded.

The aromatic compound having such an alkyl group is oxidized with molecular oxygen.

In this oxidation step, oxygen gas itself can be used as molecular oxygen, but usually, an oxygen-containing gas such as air is used.

This oxidation reaction is generally performed in the presence of an alkali catalyst. As the alkali catalyst, an aqueous sodium hydroxide solution or the like is preferably used.

This reaction is usually carried out at 70 to 120 ° C., preferably 90 to 110 ° C.
The reaction is carried out at a temperature in the range of ° C., and the reaction time is usually 5 to 60 hours.

For example, by oxidizing m-diisopropylbenzene with the above molecular oxygen, diisopropylbenzene monohydroperoxide (MH
P), diisopropylbenzene dihydroperoxide (DH
In addition to P) and diisopropylbenzene monocarbinol monohydroperoxide (HHP), various oxides such as diisopropylbenzene dicarbinol (DC) are formed.

Next, the oxide thus produced is dissolved in the organic solvent by bringing the oxide into contact with the organic solvent. The aqueous alkaline solution used as a catalyst is usually separated at this stage.

As the organic solvent used here, a solvent that can selectively dissolve the above oxide can be used. Examples of such organic solvents include aromatic solvents, and specific examples include benzene and
Mention may be made of toluene, xylene, ethylbenzene, cumene, cymene and diisopropylbenzene.
In particular, in the present invention, it is preferable to use a solvent which can form an azeotrope with water and has a relatively low boiling point as the organic solvent, and toluene is particularly preferable.

The organic solvent solution thus prepared is then reoxidized using hydrogen peroxide. In the present invention, the water content in the organic solvent solution is 1.09% by weight.
Below, preferably 0.1 to 1.09% by weight, particularly preferably 0.3 to 1.
To 1.0% by weight. By reducing the water content of the organic solvent solution to 1.09% by weight or less as described above, DHP can be produced with a yield of 90% by mole or more, and reoxidation using hydrogen peroxide is performed. Even if it does, no particular problem occurs. Incidentally, the water content tends to increase the DHP yield as it decreases within the above range, 0.1%
Since lowering the percentage by weight requires a large amount of equipment and the like, the advantages associated with the improvement in the yield of DHP are offset, and the industrial advantages are lost.

The water content as described above can be reduced by using a drying agent or a dehydrating agent, or by using a method such as extractive distillation, but a method of removing water by azeotropic distillation is advantageous. Therefore, in the present invention, a method of removing water by azeotropic distillation using toluene capable of forming an azeotropic mixture with water as an organic solvent is particularly preferable. This azeotropic distillation can be performed by a usual method. That is, in a solution in which the oxide is dissolved in toluene,
The water mixed with the toluene and the oxide mixed with the oxide are usually contained in an amount of about 3.5% by weight. By azeotropic distillation of such a solution, an azeotropic mixture of toluene and water is formed. It is distilled off, and the water content in the toluene solution decreases. Such azeotropic distillation can be performed according to a usual method.

When the water content is reduced by azeotropic distillation, the organic solvent is usually used in an amount of 30 to 400 parts by weight, preferably 50 to 300 parts by weight, based on 100 parts by weight of the oxide.

After adjusting the water content in the organic solvent solution as described above, in order to convert the aromatic carbinols into an aromatic hydroperoxide compound, hydrogen peroxide is added to the organic solvent solution to dissolve the oxidized solution. Oxidize the material again. This reoxidation reaction is usually performed in the presence of an acid catalyst.

As the hydrogen peroxide used here, an aqueous solution of hydrogen peroxide having a concentration of 20% or more is usually used, but it is also possible to use a compound capable of forming such hydrogen peroxide. it can.

Hydrogen peroxide contains HHP 1 contained in the organic solvent solution phase.
It is usually used in an amount of 0.5 to 20 mol, preferably 1 to 5 mol, per mol.

When an acidic catalyst is used in the re-oxidation, sulfuric acid, phosphoric acid, and perchloric acid can be used as the acid catalyst, and sulfuric acid is particularly preferable.

Such an acid catalyst is supplied and used so that the concentration in the aqueous phase is usually 5 to 40% by weight, preferably 10 to 30% by weight.

Such reoxidation using hydrogen peroxide can be performed in various reaction modes such as a batch type and a continuous type.
In addition, such a reaction may be performed by a multi-stage stirring reactor described in Japanese Patent Application No. 63-275384, which is filed on October 31, 1988, in addition to a conventional tank-type reactor. The reaction can be performed using a tubular reactor or the like.

For example, in a continuous reoxidation reaction using a multi-stage stirring reactor, an organic solvent solution of an oxide whose water content is adjusted to a specific amount or less as described above is mixed with a hydrogen peroxide and an acid catalyst in the first step. Is supplied to the reaction stirring device 2a.

The first reaction stirrer 2a includes, for example, a motor 4a
A high-speed stirrer including a stirring blade 3a and the like rotating by the rotation is provided. The high-speed stirrer used here has a stirring ability with a peripheral speed (the product of the distance r from the center to the outer edge of the rotor and the angular velocity ω) of usually 1 m / sec or more, preferably 5 m / sec or more. What you do. The concentration of hydrogen peroxide in the first reaction stirring device is usually 20% by weight or more,
Preferably, it is adjusted to 20 to 50% by weight or more. The weight ratio of the oil phase / aqueous phase supplied to the first reaction and stirring device 2a is usually set to 10 or more, preferably in the range of 20 to 35. The reaction temperature in the first reaction stirring device 2a as described above is usually 30 to 60 ° C, and the reaction time is 1 to 60 minutes.

After the reaction is performed in the first reaction stirring device under such conditions, at least a part of the reaction solution is introduced into the second reaction stirring device 2b. The second reaction stirrer 2b is similarly provided with a stirring blade 3b rotated by a motor 4b. The reaction temperature in the second stirred reactor 2b is usually 30 to 60 ° C, and the reaction time is 1 to 60 minutes.

After the reaction is performed by the second reaction stirring device in this manner, at least a part of the reaction solution is stirred by the stirring blade 3c rotated by the motor 4c.
To the third reaction stirring device 2c having Similarly, if necessary, the reaction liquid is continuously supplied to the fourth, fifth,...

Next, the reaction liquid from the reaction stirring device is introduced into the separation device 5 to perform oil-water separation, and then the oil phase is acid-decomposed.

In addition, for example, as shown in FIG. 2, for example, as shown in FIG. 2, a reoxidation reaction using a tubular stirring reactor is performed by passing an organic solvent solution of an oxide having a water content adjusted to a specific amount or less as described above. The mixture is supplied to the tubular reactor 11 together with the hydrogen oxide and the acid catalyst. In this case, the ratio of the supply amounts of the hydrogen peroxide and the acid catalyst to the organic solvent solution and the like are the same as those in the case where the above-described reaction stirring device is used.

An organic solvent solution of an oxide and a mixed solution of hydrogen peroxide and an acid catalyst supplied to the inside of such a tubular reactor 11 are:
It flows in a turbulent state in the device. As a method of forming a turbulent flow in the apparatus, a method of disposing a baffle plate (not shown) or the like in the tubular reactor can be used. As shown in FIG. It is possible to adopt a method of providing the stirring blade 13 in a shape of a circle. In particular, when the tubular reactor 11 is used, the Reynolds number [R _e = (dUρ) / μ] calculated from the inner diameter d of the cylinder, the average flow velocity U of the fluid, the density ρ of the fluid, and the density μ of the fluid is usually 2000 or more. It is preferable to set the stirring conditions so that When using such a tubular reactor, the inner diameter of the reaction tube is usually 10 to 100 mm,
The average velocity of the liquid is usually 0.1 to 5.0 m / sec, and the length of the reaction tube is
Although it can be appropriately set in consideration of the residence time, it is usually 10 to 500 m.

After reoxidation in this manner, the oil phase and the aqueous phase are separated by the separation device 5, and the oil phase is neutralized, concentrated if necessary, and then subjected to acid decomposition.

In the acid decomposition step for obtaining DHP contained in the oil phase, a conventionally known method can be employed. Specifically, DH
For the acid decomposition reaction of P, for example, ketones such as acetone, methyl ethyl ketone or diethyl ketone are added to the above oil phase, an acid decomposition catalyst is added in an amount of 0.001 to 15% by weight, and 40 to 100 ° C. Preferably, it can be performed at a temperature of 60 to 90 ° C.

Examples of the acid catalyst used herein include inorganic acids such as sulfuric acid, sulfuric anhydride, hydrofluoric acid, perchloric acid, hydrochloric acid and phosphoric acid; solid acids such as strongly acidic ion exchange resins and silica alumina; chloroacetic acid; Organic acids such as methanesulfonic acid, benzenesulfonic acid and paratoluenesulfonic acid, and heteropolyacids such as phosphotungstic acid and phosphomolybdic acid can be exemplified.

In addition, although the above description mainly described the case of producing resorcinol, the present invention is not limited to resorcinol,
The same applies when producing polyhydric phenols such as hydroquinone or phloroglucin.

According to the method for producing a polyhydric phenol according to the present invention,
Since the water content of the organic solvent solution obtained by dissolving the oxide oxidized by molecular oxygen in the organic solvent is low, for example, HHP, DC, etc. can be efficiently oxidized by a reoxidation reaction using hydrogen peroxide. To produce peroxides such as DHP. Then, a polyhydric phenol such as resorcinol can be efficiently produced by acid-decomposing a peroxide such as DHP.

By reducing the water content in the organic solvent solution in this manner, the stability of the reaction during reoxidation is not impaired.

Next, the present invention will be described with reference to examples, but the present invention should not be construed as being limited to these examples.

Example 1 According to a conventional method, 100 g of m-diisopropylbenzene was
Air oxidation in the presence of NaOH water, then 130 g of this oxide
Was dissolved in toluene to prepare a toluene solution of the oxide.

This toluene solution contains 3.8% by weight of water.

The water content in the solution was reduced to 0.21% by weight by azeotropic distillation with toluene while further adding toluene if necessary.

Table 1 shows the composition of the oxide dissolved in the toluene solution.

100 g of a toluene solution of the oxide obtained as described above
Then, 3.9 g of 48% hydrogen peroxide 19% sulfuric acid aqueous solution was added thereto, and a batch reoxidation reaction was carried out at 54.5 ° C. for 3 minutes in a strong stirring type reaction tank (9000 rpm).

 Table 2 shows the composition of the obtained reoxide.

Table 6 shows the yields (1) and (2) of the obtained DHP and the conversion of HHP.

Examples 2 to 4 In Example 1, the azeotropic conditions were changed to change the water content in the toluene solution of the oxides to 0.56% by weight (Example 2), 0.75% by weight (Example 3) and 1.09% by weight. A toluene solution of the oxide was prepared in the same manner as in (Example 4).

Table 3 shows the composition of the oxide contained in this toluene solution.

Using the toluene solution of the oxide obtained as described above, the temperature at the time of reoxidation was 54.4 ° C. (Example 2), 54.2 ° C.
A reoxidation reaction was carried out in the same manner as in (Example 3) and 54.2 ° C (Example 4).

 Table 4 shows the composition of the reoxide obtained.

Table 6 shows the yields (1) and (2) of the obtained DHP and the conversion of HHP.

Comparative Example 1 Reoxidation was carried out in the same manner as in Example 1, except that the water content in the toluene solution of the oxide was changed to 2.5% by weight.

 Table 5 shows the composition of the reoxide obtained.

Table 6 shows the yields (1) and (2) of the obtained DHP and the conversion of HHP.

As described above, the DHP yield can be improved by reducing the water content of the oxide in the toluene solution. In addition, no abnormal reaction was observed by reducing the water content.

[Brief description of the drawings]

FIG. 1 and FIG. 2 are flowcharts of a manufacturing method that can be employed in the present invention. 2a, 2b, 2c: stirring reactor, 3a, 3b, 3c: stirring blade, 4a, 4b, 4c, 14: motor, 5: separation device, 11: tubular reactor, 13: spiral Stirring blade

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁶ , DB name) C07C 39/08-39/10 C07C 37/08 C07C 27/00 310

Claims (1)

(57) [Claims] An oxidized aromatic compound having an alkyl group, obtained by oxidizing an aromatic compound having an alkyl group with molecular oxygen, is dissolved in an organic solvent and then reoxidized with hydrogen peroxide. When an aromatic hydroperoxide compound is generated from an aromatic carbinol, and then the aromatic hydroperoxide compound is acid-decomposed to produce a polyhydric phenol, the aromatic compound having an oxidized alkyl group is dissolved. Water content in the organic solvent solution is 1.09
A method for producing polyhydric phenols, wherein hydrogen peroxide is reoxidized to not more than weight%.