JP2001163819A - METHOD OF MANUFACTURING alpha,beta-UNSATURATED KETONE - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of manufacturing an α,β-unsaturated ketone expressed by general formula (II) in a high yield without industrial problem even in the presence of an iron ion in the reaction system which is a reaction inhibitor, in reacting an aldehyde expressed by general formula (I) R1CHO (R1 is a (substituted)alkyl, a hydrocarbon group having a >3C (substituted) alicyclic skeleton, an alkyl having a hydrocarbon group having the alicyclic skeleton, a (substituted)heterocycle or a (substituted)phenyl.), and an alkali metal acetoacetate or an alkali earth metal acetoacetate in the presence of a base in a mixed solvent of water and an organic solvent sparingly soluble in water. SOLUTION: In the reaction system, an aldehyde is allowed to coexist with at least one kind selected from the group consisting of phosphoric acid, metaboric acid, silicic acid, polyphosphoric acid and their alkali metal salt or alkali earth metal salt.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a process for producing an .alpha.,. Beta.-unsaturated ketone which is useful as an intermediate for agrochemicals.

[0002]

2. Description of the Related Art Conventionally, α, β- represented by the general formula (I)
Several methods have been reported for synthesizing unsaturated ketones by condensation of alkali metal acetoacetate with aldehydes.
For example, JP-A-57-4930 describes that an alkali metal salt of acetoacetic acid and an aldehyde are reacted in a mixed solution of a water-insoluble organic solvent and water using an aliphatic secondary amine as a catalyst. ing.

Japanese Patent Application Laid-Open No. 161456/1991 discloses that a reaction similar to that described above is carried out for a specific aliphatic carboxylic acid, particularly as a useful reaction when an aldehyde having a side chain at the α-position is used. It is described that a grade amine is used to keep the pH constant with a mineral acid and to adjust the amount of water for the reaction.

[0004]

However, when a small amount of iron ions of about several ppm is present in these reaction systems, the reaction is inhibited, and a large amount of β-hydroxyketone is by-produced, and the yield becomes extremely low. The problem of getting lost became apparent. In order to suppress such inhibition of iron ions, chelating agents that capture iron ions (for example, 2,2′-bipyridyl,
Attempts to use 1,10-phenanthroline, etc.) have had the problem that the inhibitory effect is weak, and these chelating agents are precipitated in the step of recovering the base, resulting in extremely poor liquid separation.

[0005] The present invention provides a process for producing an α, β unsaturated ketone, which is a target substance, in high yield even when iron ions which are inhibitors of the reaction are present in the reaction system, and which has no industrial problem. It provides a method.

[0006]

Means for Solving the Problems The present inventors have made intensive studies to solve the above-mentioned problems, and as a result, by allowing a specific acid or an alkali metal salt or an alkaline earth metal salt thereof to be present in a reaction system, The present inventors have found that the desired α, β unsaturated ketone can be obtained in good yield, and have completed the present invention.

That is, the present invention relates to an alkali metal salt or an alkaline earth metal salt of acetoic acid in a mixed solvent of water and a poorly water-soluble organic solvent in the presence of a base and a compound of the formula (I)

Embedded image R ¹ CHO (wherein, R ¹ represents an optionally substituted alkyl group,
A hydrocarbon group having a C3 or more alicyclic skeleton which may have a substituent, an alkyl group having a hydrocarbon group having the alicyclic skeleton, a plurality of cyclic groups which may have a substituent, Or a phenyl group which may have a substituent. In the reaction of the aldehyde represented by), at least one selected from the group consisting of phosphoric acid, metaboric acid, silicic acid, polyphosphoric acid, and alkali metal salts or alkaline earth metal salts thereof is coexistent. The general formula (I
I)

Embedded image (In the formula, R ¹ represents the same group as described above.)
The present invention relates to a method for producing a β-unsaturated ketone (Claim 1).

More specifically, at least one selected from the group consisting of phosphoric acid, metaboric acid, silicic acid and polyphosphoric acid is added in an amount of 0.1 to 30 mol% based on the aldehyde represented by the general formula (I). The method for producing an α, β-unsaturated ketone according to claim 1 (claim 2), wherein the base is an aliphatic secondary amine. The present invention relates to a method for producing an α, β-unsaturated ketone (claim 3).

The process for producing an α, β-unsaturated ketone according to any one of claims 1 to 3, wherein the pH is maintained in a certain range during the reaction, preferably in a range of 6 to 8. The method (Claims 4 and 5) and R in the general formula (I)
^1, wherein at least one or more substituents are provided at the 1-position.
The present invention relates to a method for producing a β-unsaturated ketone (Claim 6).

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION The alkali metal salt or alkaline earth metal acetoacetate used in the present invention includes, specifically, sodium acetoacetate, potassium acetoacetate, lithium acetoacetate, magnesium acetoacetate, calcium acetoacetate and the like. Can be exemplified.

These salts are obtained, for example, by hydrolyzing diketene or acetoacetates with an aqueous solution of sodium hydroxide, potassium hydroxide, magnesium hydroxide or the like.
It is easily obtained as an aqueous solution by removing the by-produced alcohol by concentration under reduced pressure. The concentration of the aqueous solution obtained in this manner is preferably adjusted to a concentration of 40 to 50%, since the yield decreases when a large amount of water is present in the next reaction.

In the general formula (I), R ¹ represents an alkyl group which may have a substituent, a group which may have a substituent,
A hydrocarbon group having a C3 or more alicyclic skeleton which may have a substituent, an alkyl group having a hydrocarbon group having the alicyclic skeleton, a plurality of cyclic groups which may have a substituent, It represents a multi-ring alkyl group which may have a substituent, a phenyl group which may have a substituent, or a phenylalkyl group which may have a substituent.

Specific examples of the aldehyde represented by the general formula (I) include isobutyraldehyde, 2-methylbutanal, 2-methylpentanal, 2,3-dimethylbutanal, 2-methylhexanal and 2-methylhexanal. Aliphatic aldehydes branched at the α-position of aldehydes such as ethylhexanal, 2-ethylpentanal, 2-methylheptanal, and 2-methylnonal, cyclohexanecarbaldehyde, 2-methylcyclohexanecarbaldehyde, and 3
Aldehydes having an alicyclic group such as -methylcyclohexanecarbaldehyde, 4-methylcyclohexanecarbaldehyde, 4-tetrahydropyrancarbaldehyde, 2-tetrahydrofurancarbaldehyde, 3-tetrahydropyrancarbaldehyde, 3-tetrahydrothiopyrancarbaldehyde, etc. Heterocyclic aldehyde, benzaldehyde, o
Aromatic aldehydes such as -methylbenzaldehyde, m-methylbenzaldehyde, p-methylbenzaldehyde, p-methylthiobenzaldehyde and p-chlorobenzaldehyde; phenylalkylaldehydes such as benzylaldehyde and 1-methylbenzylaldehyde; 2-pyridylmethylaldehyde; And heterocyclic alkyl aldehydes such as -pyridyl-1-methyl aldehyde.

In particular, in R ¹ in the general formula (I), 1
It is preferable to apply the method of the present invention to a reaction using an aldehyde having at least one substituent at the position, particularly an aldehyde having high water solubility. As such an aldehyde, specifically, a highly water-soluble 6 having an oxygen atom or a sulfur atom, such as 4-tetrahydropyrancarbaldehyde and 3-tetrahydrothiopyrancarbaldehyde, is used.
An aldehyde having a membered heterocyclic group can be exemplified.

As the base used in the present invention, specifically, pyrrolidine, morpholine, piperazine, 3,5-
Dimethylpiperidine, 3-butylpiperidine, 3-hexylpiperidine, 3-cyclohexylpiperidine, 4-
Benzylpiperidine, 4-phenylpiperidine, 1,3
Piperidines such as dipiperidylpropane, hexamethyleneimine, heptamethyleneimine, 3,3,5-trimethylhexahydroazepine, 1,2,3,4-tetrahydroisoquinoline, decahydroisoquinoline, 4-methyldecahydroisoquinoline, 3-azabicyclo (3,
2,2) Cyclic amines such as nonane, dimethylamine, diethylamine, di-n-propylamine, N-methyl-N
-N-butylamine, N-ethyl-NNn-butylamine, N-methyl-NNn-amylamine, N-methyl-
Examples include dialkylamines such as Nn-hexylamine and N-methyl-N-benzylamine.
However, bulky amines such as di-i-propylamine and dicyclohexylamine are not preferred. When R ¹ has one or more substituents at the 1-position, cyclic amines,
It is preferable to use N-methyl-N-substituted methylamines, and it is particularly preferable to use decahydroisoquinoline.

The method of the present invention is characterized in that the reaction is carried out in the coexistence of a specific acid or a salt thereof in order to suppress the influence of iron ions and the like. Specifically, phosphoric acid, metaboric acid,
It is preferable to use one or more selected from the group consisting of silicic acid, polyphosphoric acid, and alkali metal salts or alkaline earth metal salts thereof. The amount to be used depends on the amount of iron ions present in the reaction system, but is 5 moles to iron ions.
It is preferably used at least 00 times, especially at least 1500 times.
If the amount of iron ions mixed into the reaction system can be ascertained, the amount used can be determined from the molar ratio, but the amount used can also be determined based on the mole fraction (mol%) based on the aldehyde as the raw material.
Based on the starting aldehyde, it is preferable to use the aldehyde in an amount of 0.1 to 30 mol%. If the amount used exceeds 30 mol%, the pH of the reaction solution falls below 6.0, so that the reaction tends to be slow and the yield tends to decrease. If it is necessary to use more than this amount, even if the pH of the reaction solution temporarily falls below the optimum pH for the reaction, N
Optimum pH at the start of the reaction with alkali such as aOH
The reaction can be performed by raising it to the maximum. However,
When an aqueous solution is used as the alkali to be added, the amount of water in the system increases, the reaction slows down, and the acetoacetate may be easily decomposed. In addition, under acidic conditions, the acetoacetate salt is easily decomposed, so that it is preferable to quickly adjust the pH to the optimum. When an alkali metal salt such as phosphoric acid is added, the amount used is not particularly limited as long as the pH during the reaction is controlled in an optimum pH range.

It is preferable to use phosphoric acid having a low water content in order to reduce the amount of water in the system.
Phosphoric acid can also be used. Since high concentration phosphoric acid freezes in winter, 75% phosphoric acid is preferable for industrial use.

Examples of the poorly water-soluble solvent used in the present invention include aromatic hydrocarbons such as toluene, benzene and xylene, and aliphatic hydrocarbons such as hexane, heptane, cyclohexane and decalin. The mixing ratio of these solvents to water is 100: 5 to 100, preferably 100: 5 to 30, more preferably 100: 10 to 20.

The method of the present invention comprises: (1) a method of adding an aldehyde by adding a salt of acetoacetic acid, a base, phosphoric acid, or the like to water or a poorly water-soluble solvent, and (2) a method of adding an aldehyde or base to water or a poorly water-soluble solvent. , Phosphoric acid, etc., and acetoacetate, and (3) aldehyde, phosphoric acid, etc. to water or a poorly water-soluble solvent, and an acetoacetate, base aqueous solution. be able to. When it is necessary to adjust the pH, the method (1) is most preferable.

Although the optimum pH range varies depending on the aliphatic secondary amine used, the pH range of the reaction solution during the reaction is preferably maintained in a certain range, and more preferably in the range of pH 6 to 8. preferable. When the pH is 6 or lower, the reaction tends to be slow and the yield tends to decrease. When the pH is 8 or higher, the amount of by-product β-hydroxyketone as an intermediate tends to increase. Therefore, during the reaction, it is preferable to adjust the pH range using an acid such as a mineral acid.

The acid used for maintaining the pH is preferably a mineral acid. In order to reduce the amount of water in the system, an acid having a low water content such as concentrated sulfuric acid or 85% phosphoric acid, or an acid gas such as hydrogen chloride gas or the like is used. It is preferable to use acid anhydrides such as sulfuric anhydride and phosphorus pentoxide. Even with concentrated hydrochloric acid having a high water content, the reaction proceeds smoothly by using a high-concentration aqueous solution of the raw material alkali metal acetoacetate. When phosphoric acid is used as the mineral acid, there is no particular problem even if iron ions are present in the reaction system, provided that the molar ratio between iron ions and phosphoric acid is sufficiently ensured.

The reaction temperature is usually in the range of 10 to 60 ° C., but as the reaction temperature increases, the yield tends to decrease because the amount of by-product β-hydroxyketone as an intermediate increases. Therefore, it is preferable to carry out the reaction in a temperature range of 10 to 40 ° C.

Specific examples of the method of the present invention are shown below. 1 to 3 relative to 1 mol of the aldehyde represented by the general formula (I)
10 to 1000 ml, preferably 100 to 800 ml, per mole of aldehyde in an aqueous solution of acetoacetate
After addition of the poorly water-soluble organic solvent of 0.01 mol or more, preferably 0.05 to 0.20 mol per mol of aldehyde.
Add mole of base. With sufficient stirring, at least one selected from the group consisting of phosphoric acid, metaboric acid, silicic acid, and alkali metal salts thereof is added in an amount of 0.001 mol to 0.30 mol per 1 mol of the aldehyde. To adjust the pH to 6.0-8.0.

Then, at 10 to 60 ° C., pH 6.0 with acid.
While maintaining at ~ 8.0, 1 mole equivalent of aldehyde was added and
Stir for ~ 10 hours. After the completion of the reaction, water is added, and an acid is added to adjust the pH to 2 or less, and the organic layer is separated from the aqueous layer. Further, the organic layer is neutralized with an alkali and then washed with water to separate the organic layer from the aqueous layer, and the organic layer is concentrated under reduced pressure to obtain the desired α, β.
An unsaturated ketone can be obtained.

The aqueous layer separated from the organic layer is adjusted to a pH of 13 or more with an alkali such as sodium hydroxide and extracted with a poorly water-soluble organic solvent, whereby 97% or more of the base used as a catalyst can be recovered. The used base can be reused. The poor liquid separation observed when using a chelating agent instead of phosphoric acid or the like did not cause any problem in this case.

[0026]

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to these examples.

EXAMPLE 1 371.6 g (3.2 mol) of acetoacetic acid methyl ester and 13 parts of ion-exchanged water were placed in a reactor having a capacity of 1000 ml.
4.4 g, 25% NaOH containing 2.8 ppm of iron ions while maintaining the internal temperature at 35 to 40 ° C. while stirring with water cooling.
537.6 g (3.36 mol) of an aqueous solution was added dropwise over 4 hours, and then stirring was continued at 35 to 40 ° C for 2 hours. Then, water and methanol were distilled off under reduced pressure at a temperature of 40 ° C or lower. A part of the contents of the flask was taken out and subjected to pH titration with a 1N hydrochloric acid standard aqueous solution. As a result, the concentration of the obtained sodium acetoacetate aqueous solution was 49%. 176.7 g (0.695 mol) from this sodium acetoacetate aqueous solution
And placed in a reactor having an internal volume of 1000 ml, then 150 ml of toluene and 6.96 of decahydroisoquinoline.
g (0.05 mol), 5.0 g of 85% phosphoric acid (0.04
3 mol), and the pH was further adjusted to 7.4 with concentrated sulfuric acid.
Among them, 4-tetrahydropyrancarbaldehyde 57.
After 1 g (0.5 mol) was added dropwise over 1 hour, stirring was continued for 3 hours. During the reaction, the temperature was maintained at 20 to 25 ° C., and the pH was maintained at 7.4 ± 0.1 by dropwise addition of concentrated sulfuric acid.
After completion of the reaction, 80.0 g of water was added, and the pH was adjusted to 1.
After heating to 65 ° C. as 5, the organic layer was separated from the aqueous layer. To the separated aqueous layer, 37.5 ml of toluene was added for extraction, the organic layer was separated from the aqueous layer, and then mixed with the first separated organic layer. 2.3% 25% aqueous NaOH solution in the organic layer
After adding g to neutralize, the organic layer was separated from the aqueous layer. Further, 10 g of water was added to the organic layer, and the mixture was stirred and washed with water. The organic layer was separated from the aqueous layer, and dried over anhydrous magnesium sulfate. After filtering off magnesium sulfate, the solvent was distilled off under reduced pressure, and the remaining oily substance was further distilled off under reduced pressure to give a boiling point of 91 to 91.
73.9 g of a colorless oil at 95 ° C. (0.013 kPa)
I got (Crude yield 95.8%) When analyzed by gas chromatography, the purity of the target product, 4- (4-tetrahydropyranyl) -3-buten-2-one, was 95.1%.
Met. (Yield: 91.2%) In addition, 4.9% of 4-hydroxy-4- (4-tetrahydropyranyl) -butan-2-one as a by-product was contained, and the yield based on 4-tetrahydropyrancarbaldehyde was contained. Was 4.2%.

Example 2 176.7 g (0.695 mol) of the same 49% aqueous solution of sodium acetoacetate as used in Example 1 was used.
2,000 ml reactor, then 150 m
1, 6.96 g (0.05 mol) of decahydroisoquinoline and 2.5 g (0.022 mol) of 85% phosphoric acid were added, and the pH was further adjusted to 7.4 with concentrated sulfuric acid. 4-
57.1 g of tetrahydropyrancarbaldehyde (0.5
Mol) was added dropwise over 1 hour, and then stirring was continued for 3 hours.
During the reaction, the temperature was maintained at 20 to 25 ° C., and the pH was maintained at 7.4 ± 0.1 by dropwise addition of concentrated sulfuric acid. After completion of the reaction, 80.0 g of water was added, and the pH was adjusted to 1.5 with concentrated sulfuric acid to 65.
After raising the temperature to ° C., the organic layer was separated from the aqueous layer. To the separated aqueous layer, 37.5 ml of toluene was added for extraction, the organic layer was separated from the aqueous layer, and then mixed with the first separated organic layer. The organic layer was neutralized by adding 5.2 g of a 25% aqueous NaOH solution, and then the organic layer was separated from the aqueous layer. Further, 10 g of water was added to the organic layer, and the mixture was stirred and washed with water. The organic layer was separated from the aqueous layer, and dried over anhydrous magnesium sulfate. After filtering off magnesium sulfate, 256.1 g of an organic layer was obtained. A part of the organic layer was sampled and analyzed by an internal standard method using a standard having a purity of 99.9% by high performance liquid chromatography to find that the target product was 4- (4-tetrahydropyranyl).
The concentration of -3-buten-2-one was 27.0%.
(89.8% yield) 4-hydroxy-4- by-product
The concentration of (4-tetrahydropyranyl) -butan-2-one was 1.4%, and the yield based on 4-tetrahydropyrancarbaldehyde was 4.2%.

Comparative Example 1 176.7 g (0.695 mol) of the same 49% aqueous solution of sodium acetoacetate as that synthesized in Example 1 was used.
2,000 ml reactor, then 150 m
l, 6.96 g (0.05 mol) of decahydroisoquinoline was added, and the pH was further adjusted to 7.4 with concentrated sulfuric acid. 57.1 g of 4-tetrahydropyrancarbaldehyde was added thereto.
(0.5 mol) was added dropwise over 1 hour, and then stirring was continued for 4 hours. During the reaction, the temperature was maintained at 20 to 25 ° C., and the pH was maintained at 7.4 ± 0.1 by dropwise addition of concentrated sulfuric acid. After completion of the reaction, 80.0 g of water was added, and the pH was raised to 65 ° C. with concentrated sulfuric acid to 1.5, and then the organic layer was separated from the aqueous layer. To the separated aqueous layer, 37.5 ml of toluene was added for extraction, the organic layer was separated from the aqueous layer, and then mixed with the first separated organic layer. 5.5 g of 25% NaOH aqueous solution in the organic layer
After the addition, the organic layer was separated from the aqueous layer. Further, 10 g of water was added to the organic layer, and the mixture was stirred and washed with water. The organic layer was separated from the aqueous layer, and dried over anhydrous magnesium sulfate.
After filtering off magnesium sulfate, 247.9 g of an organic layer was obtained. A part of the organic layer was sampled and analyzed by high performance liquid chromatography using an internal standard method using a standard having a purity of 99.9% to find that the target product, 4- (4-tetrahydropyranyl) -3-butene-2, was obtained. -On concentration of 24.9
%Met. (Yield: 79.9%) By-product 4-hydroxy-4- (4-tetrahydropyranyl) -butane-
The concentration of 2-one was 3.2%, and the yield based on 4-tetrahydropyrancarbaldehyde was 9.1%.

Example 3 109.1 g of a 47.4% aqueous sodium acetoacetate solution synthesized under the same conditions as in Example 1 using ion-exchanged water and NaOH adjusted to a concentration of 25% with reagent-grade NaOH.
(0.417 mol) was placed in a reactor having an internal volume of 1000 ml, and 0.6 g of an aqueous solution of iron (III) chloride containing 0.004 g (0.000075 mol) of iron ions was added. (The added iron ion is equivalent to 0.025 mol per 1 mol of 4-tetrahydropyrancarbaldehyde) Then, 90 ml of toluene and 4.2 g of decahydroisoquinoline (0.03 mol
Mol) and 1.5 g (0.015 mol) of 85% phosphoric acid, and the pH was further adjusted to 7.4 with concentrated sulfuric acid. 4-
34.2 g of tetrahydropyrancarbaldehyde (0.3
Mol) was added dropwise over 1 hour, and then stirring was continued for 3 hours.
During the reaction, the temperature was maintained at 20 to 25 ° C., and the pH was maintained at 7.4 ± 0.1 by dropwise addition of concentrated sulfuric acid. After the completion of the reaction, 48.0 g of water was added, and the pH was adjusted to 1.5 with concentrated sulfuric acid to 65.
After raising the temperature to ° C., the organic layer was separated from the aqueous layer. To the separated aqueous layer, 22.5 ml of toluene was added for extraction, and the organic layer was separated from the aqueous layer and then mixed with the first separated organic layer. The organic layer was neutralized by adding 1.8 g of a 25% aqueous NaOH solution, and then the organic layer was separated from the aqueous layer. Further, 6 g of water was added to the organic layer, and the mixture was stirred and washed with water. The organic layer was separated from the aqueous layer, and dried over anhydrous magnesium sulfate. After filtering off magnesium sulfate, 181.7 g of an organic layer was obtained. A part of the organic layer was sampled and analyzed by an internal standard method using a standard having a purity of 99.9% by high performance liquid chromatography to find that the target product was 4- (4-tetrahydropyranyl).
The concentration of -3-buten-2-one was 21.3%.
(83.7% yield) 4-hydroxy-4- by-product
The concentration of (4-tetrahydropyranyl) -butan-2-one was 1.9%, and the yield based on 4-tetrahydropyrancarbaldehyde was 6.7%.

Comparative Example 2 179.6 g of a 47.4% aqueous sodium acetoacetate solution synthesized under the same conditions as in Example 1 using ion-exchanged water and NaOH adjusted to a concentration of 25% with reagent-grade NaOH.
(0.695 mol) was placed in a reactor having an internal volume of 1000 ml, and 1.0 g of an aqueous solution of iron (III) chloride containing 0.007 g (0.000125 mol) of iron ions was added. (The added iron ion corresponds to 0.025 mol per 1 mol of 4-tetrahydropyrancarbaldehyde) Then, 150 ml of toluene and 7.0 g of decahydroisoquinoline (0.0 g
5 mol), and the pH was further adjusted to 7.4 with concentrated sulfuric acid.
Among them, 4-tetrahydropyrancarbaldehyde 57.
After 1 g (0.5 mol) was added dropwise over 1 hour, stirring was continued for 4 hours. During the reaction, the temperature was maintained at 20 to 25 ° C., and the pH was maintained at 7.4 ± 0.1 by dropwise addition of concentrated sulfuric acid.
After completion of the reaction, 80.0 g of water was added, and the pH was adjusted to 1.
After heating to 65 ° C. as 5, the organic layer was separated from the aqueous layer. To the separated aqueous layer, 37.5 ml of toluene was added for extraction, the organic layer was separated from the aqueous layer, and then mixed with the first separated organic layer. 25% NaOH aqueous solution 2.5 in organic layer
After adding g to neutralize, the organic layer was separated from the aqueous layer. Further, 10 g of water was added to the organic layer, and the mixture was stirred and washed with water. The organic layer was separated from the aqueous layer, and dried over anhydrous magnesium sulfate. After filtering off magnesium sulfate, 279.5 g of an organic layer was obtained. A part of the organic layer was sampled and analyzed by high performance liquid chromatography using an internal standard method using a standard having a purity of 99.9% to find that the target product, 4- (4-tetrahydropyranyl) -3-butene-2, was obtained. The concentration of -one is 16.
3%. (Yield 59.0%) The concentration of by-product 4-hydroxy-4- (4-tetrahydropyranyl) -butan-2-one was 6.9%, and the yield based on 4-tetrahydropyrancarbaldehyde Was 22.2%.

[0032]

As described above, when the method of the present invention is used, the reaction proceeds without being suppressed by metal ions such as iron contained in the water used in the reaction, so that by-products are formed. , And the desired α, β-unsaturated ketone compound can be synthesized in a high yield, and is excellent as an industrial production method without problems in the reaction operation such as liquid separation.

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Tsuyoshi Nishiwaki 950, Fujisawa 950, Nakago-mura, Nakakushijo-gun, Niigata Japan F-term in Nihon Soda Co., Ltd. Nihongi Plant Production Engineering Laboratory 4H006 AA02 AC22 AC25 BA33 BA35 BA51 BB11 BB31 BC16 4H039 CA62 CD40 CD90

Claims (6)

[Claims] An alkali metal salt or an alkaline earth metal salt of acetoacetic acid in a mixed solvent of water and a poorly water-soluble organic solvent in the presence of a base, and a compound represented by the general formula (I): R ¹ CHO , R ¹ is an alkyl group which may have a substituent,
A hydrocarbon group having a C3 or more alicyclic skeleton which may have a substituent, an alkyl group having a hydrocarbon group having the alicyclic skeleton, a plurality of cyclic groups which may have a substituent, Or a phenyl group which may have a substituent. In the reaction of the aldehyde represented by the formula (1), at least one selected from the group consisting of phosphoric acid, metaboric acid, silicic acid, polyphosphoric acid and their alkali metal salts or alkaline earth metal salts is coexistent. The general formula (I
I) (In the formula, R ¹ represents the same group as described above.)
Method for producing β-unsaturated ketone. 2. The method according to claim 1, wherein at least one selected from the group consisting of phosphoric acid, metaboric acid, silicic acid and polyphosphoric acid is used in an amount of 0.1 to 30 m with respect to the aldehyde represented by the formula (I).
ol%, α, according to claim 1, characterized in that
Method for producing β-unsaturated ketone. 3. The method for producing an α, β-unsaturated ketone according to claim 1, wherein the base is an aliphatic secondary amine. 4. The method according to claim 1, wherein the pH is maintained within a certain range during the reaction.
A method for producing an unsaturated ketone. 5. The method for producing an α, β-unsaturated ketone according to claim 4, wherein the pH range is from 6 to 8. 6. The α, β-unsaturated ketone according to claim ^1, wherein R ¹ in the general formula (I) has at least one substituent at the 1-position. Production method.