JPH0525080A - Production of cycloalkanone - Google Patents

Abstract

PURPOSE:To provide a method for producing a cycloalkanone by efficiently oxidizing a cycloalkanol with hydroperoxide. CONSTITUTION:A cycloalkanol is reacted with hydrogen peroxide in the presence of tungstenic acid and a quaternary ammonium salt, e.g. tetrabutylammonium bromide, in a homogeneous system to produce a cycloalkanone, e.g. 4-methylcyclohexanone.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for producing cycloalkanone, and more particularly to a method for producing a corresponding cycloalkanone by oxidizing cycloalkanol with hydrogen peroxide.

[0002]

2. Description of the Related Art As a method for producing a corresponding cycloalkanone by oxidizing a cycloalkanol such as cyclohexanol or 4-methylcyclohexanol, the method described in J. Org. Chem. , 52, 1
868 (1987) and J. Org. Chem. ，
53, 3587 (1988) discloses a method of oxidizing with hydrogen peroxide using a compound obtained by reacting a heteropolyacid with cetylpyridinium chloride as a catalyst. Although the catalyst used in this method has an excellent catalytic ability, it has a problem that it requires a separate reaction step for preparing the catalyst and also requires an excess of hydrogen peroxide. Tetrahed
ron Lett. , 25, 173 (1984) discloses a method of oxidizing with hydrogen peroxide using a catalyst composed of ammonium molybdate, potassium carbide and tetrabutylammonium chloride, but the problem that it takes a long time to complete the reaction is disclosed. Have. Chem. Lett. ，
1984, 1247 discloses a method of oxidizing with oxygen using a catalyst composed of rhodium chloride and triphenylphosphine, but it has a problem that the yield of the desired product is low and the catalyst is difficult to obtain. See also
-26657 and Japanese Patent Laid-Open No. 50-149649 disclose a method for producing a corresponding cycloalkanone by oxidizing a phenol such as p-cresol in the liquid phase with hydrogen in the presence of a palladium catalyst. This method has a problem that a separate reaction step is required for the preparation of the catalyst and cycloalkanol tends to be produced as a by-product, and if this is produced as a by-product, a separate oxidation step is required.

An object of the present invention is to solve the above-mentioned problems of the prior art, and by a particularly simple operation, without the need for excess hydrogen peroxide as seen in a heterogeneous reaction, It is an object of the present invention to provide a method for producing a cycloalkanone by oxidizing a cycloalkanol with hydrogen peroxide, which makes it possible to produce a desired cycloalkanone in a short time in a high yield, and which allows repeated use of a catalyst.

[0004]

The present invention provides a method for producing cycloalkanone, which comprises reacting cycloalkanol and hydrogen peroxide in a homogeneous system in the presence of tungstic acid and a quaternary onium salt. is there.

As the cycloalkanol used in the method of the present invention, a substituted or unsubstituted cycloalkanol can be used as long as it is a compound which can be converted into a corresponding cycloalkanone by oxidation. Specific examples include cyclohexanol and 4
-Alkyl-substituted cyclohexanol such as methylcyclohexanol and the like.

Hydrogen peroxide is used in aqueous solution. The hydrogen peroxide can be used in an excess amount with respect to the starting material cycloalkanol, but about 1 molar equivalent is sufficient. The concentration of the aqueous hydrogen peroxide solution used is not particularly limited and is usually 5 to 5.
Those having a concentration of 90% by weight, particularly 35 to 60% by weight are preferably used.

The amount of tungstic acid used as one component of the catalyst is preferably in the range of 1 / 1,000 to 1 molar equivalent, particularly 1/100 to 1/500 molar equivalent with respect to hydrogen peroxide. preferable.

The amount of the quaternary onium salt, which is the other component of the catalyst, is preferably in the range of 1/5 to 10 molar equivalents, particularly preferably in the range of 1/2 to 2 molar equivalents, with respect to tungstic acid.

As the quaternary onium salt, a quaternary ammonium salt or a quaternary phosphonium salt is used.

Specific examples of the quaternary ammonium salt include tetrabutylammonium bromide, tetrabutylammonium chloride, tetrabutylammonium hydrogen sulfate, tetramethylammonium bromide, tetraethylammonium bromide, tetrapropylammonium bromide and bromide. Tetrabentyl ammonium, tetradecyl ammonium bromide, methyltrioctyl ammonium chloride, hexyl trimethyl ammonium bromide, tetradecyl trimethyl ammonium bromide, cetyl trimethyl ammonium chloride, phenyl trimethyl ammonium bromide, benzyl tetradecyl dimethyl ammonium bromide is there.

Specific examples of the quaternary phosphonium salt include tetrabutylphosphonium bromide, hexyltrimethylphosphonium bromide, tetraphenylphosphonium bromide, butyltriphenylphosphonium bromide, pentyltriphenylphosphonium bromide, and heptyltrinium bromide. There are phenylphosphonium, benzyltriphenylphosphonium chloride, bromomethyltriphenylphosphonium bromide, and bromopropyltriphenylphosphonium bromide.

Of the above-mentioned onium salts, tetrabutylammonium bromide and tetraphenylphosphonium bromide are most suitable in terms of economy and reactivity.

The essence of the present invention is to carry out the above reaction in a homogeneous system. The homogeneous system is formed by using hydrogen peroxide as an aqueous solution and combining it with a water-soluble organic solvent capable of forming a homogeneous system. The water-soluble organic solvent may be essentially any water-soluble organic solvent as long as it can maintain the entire reaction system in a uniform system including the target product cycloalkanone, and may be used as a raw material compound or a target product to be used. Although it can be appropriately selected depending on the case, since the raw material compound may be an alcohol-based compound, it cannot be said to be an alcohol-based water-soluble organic solvent. A particularly preferred water-soluble organic solvent is acetonitrile. The water-soluble organic solvent may be used in any amount as long as it can maintain the system in a homogeneous system, and is used, for example, in an amount of about 5 to 30 times by weight based on the cycloalkanol.

The reaction temperature is usually 40 to 100 ° C., and particularly preferably a temperature (80 to 100 ° C.) sufficient to reflux the reaction system.

After completion of the reaction, the desired product can be obtained by an appropriate means. For example, after distilling off the water-soluble organic solvent and water by distillation, the desired product, cycloalkanone, is obtained by vacuum distillation, and the remaining catalyst is repeatedly used in the oxidation reaction.

The cycloalkanone thus obtained is a useful compound which can be used for various purposes such as a pharmaceutical intermediate and a bisazide type photosensitive resin raw material.

[0017]

【Example】

Example 1: In a separable flask having a capacity of 500 ml, 150 ml of acetonitrile, 11.4 g (0.1 mol) of 4-methylcyclohexanol, 60% hydrogen peroxide 5.
67 g (0.1 mol), tungstic acid 50.0 mg
(0.2 mmol) and 129.0 mg (0.4 mmol) of tetrabutylammonium bromide were added, and the mixture was stirred on a water bath under reflux with heating for 6 hours.

Unreacted 4-methylcyclohexanol and 4-methylcyclohexanone were analyzed by gas chromatography.

As a result, as shown in Table 1, the yield of 4-methylcyclohexanone was 100%.

Example 2-8: The reaction was performed in the same manner as in Example 1 except that the amounts of tungstic acid and tetrabutylammonium bromide used were changed.

The results are shown in Table 1.

[0022]

[Table 1] Examples 9-12: The reaction was performed in the same manner as in Example 1 except that the quaternary onium salt was changed.

The results are shown in Table 2.

[0024]

[Table 2] Examples 13-16: except that the concentration of hydrogen peroxide was changed.
The reaction was carried out in the same manner as in Example 1.

The results are shown in Table 3.

[0026]

[Table 3] Example 17: 1.50 l of acetonitrile and 4-methylcyclohexanol 11 in a 3-necked flask with a volume of 3 l
4.2 g (1.0 mol), 60% hydrogen peroxide solution 5
6.7 g (1.0 mol), tungstic acid 0.50 g
(2.0 mmol) and 1.29 g (4 mmol) of tetrabutylammonium bromide were added, and the mixture was stirred on a hot water bath under reflux with heating for 8 hours.

After the reaction was completed, the solvent and water were distilled off, and the target substance, 4-methylcyclohexanone, was obtained by distillation under reduced pressure.

The oxidation catalyst in the reaction residue was recovered and reused in the oxidation reaction.

The results are shown in Table 4.

[0030]

[Table 4] Comparative Example 1-3: The reaction was performed in the same manner as in Example 1 except that the solvent was changed.

The results are shown in Table 5.

[0032]

[Table 5] Comparative Example 4: The reaction was performed in the same manner as in Example 1 except that the quaternary onium salt was not used.

The yield of 4-methylcyclohexanone after 24 hours of the reaction was 47%.

Claims (6)

[Claims] 1. A cycloalkanol and hydrogen peroxide,
A method for producing cycloalkanone, which comprises reacting tungstic acid with a quaternary onium salt in a homogeneous system. 2. The method according to claim 1, wherein the cycloalkanol is an alkyl-substituted or unsubstituted cyclohexanol. 3. The method according to claim 1, wherein the quaternary onium salt is a quaternary ammonium salt or a quaternary phosphonium salt. 4. The medium constituting the homogeneous system comprises a mixed system of water and a water-soluble organic solvent, and forms a homogeneous system with cycloalkanol, cycloalkanone, hydrogen peroxide and quaternary onium salt. The method according to item 1. 5. The method according to claim 4, wherein the water-soluble organic solvent is a non-alcoholic solvent. 6. The method according to claim 4, wherein the water-soluble organic solvent is acetonitrile.