JP2016204318A - MANUFACTURING METHOD OF α,β-UNSATURATED CARBOXYLIC ACID - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing method which can get α,β-unsaturated carboxylic acid at a high yield by liquid phase oxidation of α,β-unsaturated aldehyde by oxygen or air with a handy metal catalyst under a mild reaction condition.SOLUTION: Preferably under a presence of organic solvent, α,β-unsaturated carboxylic acid is manufactured by oxidation of α,β-unsaturated aldehydes and oxygen or air under a presence of an iron salt catalyst and a catalyst of alkali metal salt of carboxylic acid.SELECTED DRAWING: None

Description

  The present invention relates to a novel process for producing an α, β-unsaturated carboxylic acid useful as an intermediate for various organic compounds.

As a method for producing an α, β-unsaturated carboxylic acid by oxidizing an α, β-unsaturated aldehyde, a method using sodium chlorite (see Non-Patent Document 1), silver oxide after using hydrogen cyanide (II) ) (AgO) action method (see non-patent document 2), silver oxide (I) (Ag ₂ O) method (see non-patent document 3), etc. have been reported. It is difficult to say that it is an industrially superior method in terms of the use of a high oxidizing agent and instability to light. Further, a method using hydrogen peroxide as an oxidizing agent and ruthenium chloride as a catalyst (see Non-Patent Document 4), a method using iridium, rhodium and palladium chlorides (see Non-Patent Document 5), palladium carboxylic acid Although a method using a salt (see Patent Document 1) is known, it is difficult to say that it is a practical method because an expensive noble metal is used.

  On the other hand, if α, β-unsaturated carboxylic acid can be produced from α, β-unsaturated aldehyde using oxygen or air as an oxidizing agent, it is inexpensive, non-corrosive, does not produce by-products, or is harmless. Since it is only water, the environmental load is small and it can be said that it is an excellent method for industrial use.

  As a method of producing α, β-unsaturated carboxylic acid from α, β-unsaturated aldehyde using oxygen as an oxidizing agent, a method using a catalyst supporting palladium and tungsten (Patent Document 2), molybdenum and Although a method using a solid catalyst having vanadium (Patent Document 3) is shown, only a method for producing acrylic acid and methacrylic acid is shown. On the other hand, as an example of using a metal complex catalyst, an iron catalyst method using a β-ketoester having a methacrylate moiety as a ligand has been shown, but it is necessary to use a halogen-based solvent and is excellent in environmental harmony. It cannot be said that it is a method (Non-Patent Document 6). As an example using an organic molecule as a catalyst, a method using an N-heterocyclic carbene as a catalyst is shown. However, it is necessary to add an equimolar amount of an inorganic base (Non-patent Document 7).

  Therefore, development of a method for efficiently producing α, β-unsaturated carboxylic acids from α, β-unsaturated aldehydes simply and cleanly using oxygen or air as an oxidant and inexpensive metals as catalysts is strongly desired. Yes.

JP 2010-189326 A JP 2014-203848 A JP 2013-226546 A

J. Org. Chem. 1986, 51, 567. J. Am. Chem. Soc. 1968, 90, 5616. J. Org. Chem. 1980, 45, 3698. Appl. Organomet. Chem. 2006, 20, 20. Appl. Organomet. Chem. 2007, 21, 135. J. Mol. Catal. 1994, 94, 27. Org. Lett. 2011, 13, 2422.

  The present invention has been made to overcome the above-mentioned problems of the prior art, and produces a high yield of α, β-unsaturated carboxylic acid from α, β-unsaturated aldehyde under mild reaction conditions. It is an object of the present invention to provide a simple and efficient method for producing an α, β-unsaturated carboxylic acid which can be obtained by the above-mentioned method and has a very low environmental and human impact / toxicity.

  As a result of diligent research to solve the above problems, the present inventors have used a catalyst in which an oxidizing agent is oxygen or air and a combination of an iron salt and an alkali metal salt of a carboxylic acid, in the absence of a solvent, or in a catalyst and α. We have found that α, β-unsaturated carboxylic acids can be produced in high yield from α, β-unsaturated aldehydes at room temperature using a solvent that uniformly dissolves α, β-unsaturated aldehydes. It came to do.

That is, this application provides the following invention.
<1> An α, β-unsaturated aldehyde is oxidized with oxygen or air in the presence of iron (II) or iron (III) salt and an alkali metal salt of carboxylic acid. A method for producing unsaturated carboxylic acids.
<2> The iron, II, or iron (III) salt is iron (II) acetate or iron (III) nitrate, wherein the α, β-unsaturated carboxylic acids according to <1> are used. Production method.
<3> Sodium acetate, potassium acetate, sodium trifluoroacetate, or potassium trifluoroacetate used alone or in combination of two or more as the alkali metal salt of the carboxylic acid, <1> or <2 The manufacturing method of (alpha), (beta)-unsaturated carboxylic acids described in>.
<4> The method for producing an α, β-unsaturated carboxylic acid according to any one of <1> to <3>, wherein the oxidation reaction is performed in the presence of an organic solvent.

  The method for producing an α, β-unsaturated carboxylic acid provided by the present invention comprises a variety of pharmaceutical raw materials and useful α, β-unsaturated carboxylic acid widely used as an intermediate for organic compounds under mild conditions. And in high yield. In addition, since the method of the present invention does not require the use of a base or a halogen-based solvent, it has an extremely low impact and toxicity on the environment and the human body, has the effect of reducing the burden on the environment, and is safe, simple and efficient. α, β-unsaturated carboxylic acid can be obtained. Therefore, the method of the present invention can be said to be an invention that has a great industrial effect.

  The method for producing an α, β-unsaturated carboxylic acid according to the present invention comprises oxidizing an α, β-unsaturated aldehyde and oxygen or air in the presence of a catalyst combining an iron salt and an alkali metal salt of a carboxylic acid. It is made to react.

The α, β-unsaturated aldehydes used in the production method of the present invention are represented by the general formula (1). In the formula, R ^{1 to} R ³ are each independently a hydrogen atom, alkyl group, cycloalkyl group, aryl group, aralkyl group, heteroaromatic ring group, alkoxy group, alkoxycarbonyl group, acyl group, acyloxy group, hydroxy group. , A halogen atom, a carboxyl group, an amide group, a silyl group, a phosphoryl group, a sulfinyl group, a sulfonyl group or a sulfonate group. These groups may be further substituted with a substituent. Moreover, any of R ^{1 to} R ³ may be connected to form a cyclic structure.

In the general formula (1), when R ^{1 to} R ³ are an alkyl group which may have a substituent, the alkyl group has 1 to 30 carbon atoms, preferably 1 to 20 linear or Examples include branched alkyl groups, and specific examples include a methyl group, an ethyl group, a propyl group, a hexyl group, and an octyl group.

Examples of the cycloalkyl group in the case where R ^{1 to} R ³ may have a substituent include a monocyclic, polycyclic or condensed cyclic group having 3 to 20 carbon atoms, preferably 3 to 10 carbon atoms. And more specifically, a cyclopropyl group, a cyclopentyl group, a cyclohexyl group, a cyclooctyl group, and the like.

Examples of the aryl group in the case where R ^{1 to} R ³ are an optionally substituted aryl group include a monocyclic, polycyclic or condensed cyclic aromatic group having 6 to 20 carbon atoms, preferably 6 to 14 carbon atoms. More specifically, examples thereof include a phenyl group, a tolyl group, a xylyl group, a naphthyl group, a methylnaphthyl group, an anthryl group, a phenanthryl group, and a biphenyl group.

The aralkyl group in the case where R ^{1 to} R ³ may have a substituent is, for example, a monocyclic, polycyclic or condensed cyclic group having 7 to 20 carbon atoms, preferably 7 to 15 carbon atoms. An aralkyl group is mentioned, More specifically, a benzyl group, a phenethyl group, a naphthylmethyl group, a naphthylethyl group etc. are mentioned, for example.

The heterocyclic group in the case where R ^{1 to} R ³ may have a substituent is a ^3- to 15-membered ring having at least one nitrogen atom, oxygen atom or sulfur atom in the ring. , Preferably a 3- to 10-membered ring, which may be condensed with a carbocyclic group such as a cycloalkyl group, a cycloalkenyl group or an aryl group, or a saturated or unsaturated monocyclic, polycyclic or condensed ring More specifically, for example, oxiranyl group, pyridyl group, thienyl group, phenylthienyl group, thiazolyl group, furyl group, piperidyl group, piperazyl group, pyrrolyl group, imidazolyl group, quinolyl group, pyrimidyl group, etc. Is mentioned.

Examples of the alkoxy group in the case where R ^{1 to} R ³ may have a substituent include linear or branched alkoxy groups having 1 to 20 carbon atoms, preferably 1 to 10 carbon atoms, Specific examples include methoxy group, ethoxy group, i-propoxy group, t-butoxy group and the like.

The alkoxycarbonyl group in the case where R ^{1 to} R ³ may have a substituent is a linear or branched alkoxycarbonyl group having 1 to 30 carbon atoms, preferably 1 to 20 carbon atoms. Specific examples include methoxycarbonyl group, ethoxycarbonyl group, i-propoxycarbonyl group, t-butoxycarbonyl group, phenoxycarbonyl group and the like.

Examples of the acyl group in the case where R ^{1 to} R ³ may have a substituent include linear or branched acyl groups having 1 to 30 carbon atoms, preferably 1 to 20 carbon atoms, Specific examples include acetyl group, benzoyl group, heptanoyl group, cyclohexanecarbonyl group and the like. Examples of the acyloxy group in the case where R ^{1 to} R ³ may be an acyloxy group include an acetyloxy group, a propionyloxy group, and a benzoyloxy group.

Examples of the amide group in the case where R ^{1 to} R ³ may have a substituent include linear or branched amide groups having 1 to 30 carbon atoms, preferably 1 to 20 carbon atoms, Specific examples include a methylamide group, an ethylamide group, an i-propylamide group, a tetradecylamide group, and the like.

Specific examples of the silyl group in the case where R ^{1 to} R ³ are silyl groups which may have a substituent include a trimethylsilyl group, a triethylsilyl group, and a triphenylsilyl group.

Specific examples of the phosphoryl group in the case where R ^{1 to} R ³ are a phosphoryl group which may have a substituent include a dihydroxyphosphoryl group and a dimethoxyphosphoryl group.

Specific examples of the sulfinyl group in the case where R ^{1 to} R ³ may have a substituent include a methylsulfinyl group and a phenylsulfinyl group.

Specific examples of the sulfonyl group in the case where R ^{1 to} R ³ are optionally substituted sulfonyl groups include a methylsulfonyl group and a phenylsulfonyl group. Specific examples of the sulfonate group in the case where R ^{1 to} R ³ are sulfonate groups which may have a substituent include a methyl sulfonate group and a phenyl sulfonate group.

  As substituents for these alkyl groups, cycloalkyl groups, aryl groups, aralkyl groups, heterocyclic groups, alkoxy groups, alkoxycarbonyl groups, acyl groups, amide groups, silyl groups, phosphoryl groups, sulfinyl groups, sulfonyl groups, sulfonate groups May be any substituent as long as it does not adversely affect the reaction, for example, an alkyl group such as a methyl group, an ethyl group, or a propyl group, for example, an aryl group such as a phenyl group or a naphthyl group, such as an oxiranyl group. , Heterocyclic groups such as pyridyl group, furyl group, etc., alkoxy groups such as methoxy group, ethoxy group, phenoxy group, naphthyloxy group, such as methoxycarbonyl group, i-propoxycarbonyl group, t-butoxycarbonyl group, phenoxycarbonyl group Such as alkoxycarbonyl group, sulfonic acid group, cyano group, Nitro groups such as silyl groups such as trimethylsilyl group and triphenylsilyl group, hydroxy groups such as unsubstituted amide group, methylamide group, propylamide group, tetradecylamide group and other amide groups such as acetyl group and benzoyl group Groups, for example, phosphoryl groups such as dihydroxyphosphoryl group, dimethoxyphosphoryl group, for example, sulfinyl groups such as methylsulfinyl group, phenylsulfinyl group, for example, sulfonyl groups such as methylsulfonyl group, phenylsulfonyl group, such as methylsulfonate group, phenylsulfonate And sulfonate groups such as groups.

Further, any two of R ¹ , R ² and R ³ may be bonded to each other with a residue from which a hydrogen atom has been removed to form a ring, and any ^one of R ¹ , R ² and R ³ may be formed. Residues obtained by removing hydrogen atoms from the two may be bonded to each other via a divalent atom or / and a divalent functional group to form a ring. In this case, the divalent atom is an oxygen atom, a nitrogen atom, a sulfur atom, etc., and the divalent functional group is a silylene group, an ethylenedioxy group, an aryleneoxy group, a carbonyl group, a sulfoxide group, a sulfone group. Etc. are exemplified.

  In the present invention, various α, β-unsaturated aldehydes represented by the general formula (1) can be used. Preferably, trans-2-decenal, trans-2-octenal, It is desirable to use trans-2-hexenal, 3-methyl-2-butenal, benzaldehyde-2-thiophenaldehyde-2-octenal.

  There is no limitation on the concentration and pressure of oxygen used in the production method of the present invention, and the reaction to α, β-unsaturated carboxylic acids occurs depending on the concentration and pressure, but 1 atmosphere of oxygen or 1 atmosphere of air is used. preferable.

  The iron salt is a compound that generates an iron (II) or iron (III) cation in an organic solvent, such as anhydrous iron (II) acetate, iron (II) chloride tetrahydrate, anhydrous iron (II) chloride. , Basic iron acetate (III), iron nitrate (III) nonahydrate, iron sulfate (III) hydrate, iron (III) perchlorate hydrate, anhydrous iron chloride (III), etc. Anhydrous iron (II) acetate is preferred. These may be used alone or in combination of two or more. The amount to be used is selected from the range of 0.0001 to 20 mol%, preferably 0.01 to 10 mol%, based on the α, β-unsaturated aldehyde as a substrate.

  Specific examples of the alkali metal salt of carboxylic acid include lithium acetate, sodium acetate, potassium acetate, cesium acetate, lithium trifluoroacetate, sodium trifluoroacetate, potassium trifluoroacetate, cesium trifluoroacetate, lithium pivalate, and pivalate. Examples thereof include sodium acid, potassium pivalate, cesium pivalate and the like. Of these, sodium acetate, potassium acetate, sodium trifluoroacetate, and potassium trifluoroacetate are preferable. These may be used alone or in combination of two or more. The amount to be used is selected from the range of 0.001 to 30 mol%, preferably 0.1 to 20 mol%, based on the α, β-unsaturated aldehyde as a substrate.

  In the present invention, the reaction proceeds efficiently without using a solvent. Preferably, the catalyst and α, β-unsaturated aldehydes are used as homogeneously soluble solvents such as methanol, ethanol, isopropyl alcohol, t It is better to use -butyl alcohol, N, N-dimethylformamide, ethyl acetate, dimethyl sulfoxide, tetrahydrofuran, acetonitrile, benzonitrile, acetone, etc., and ethyl acetate is particularly desirable. These may be used alone or in combination of two or more. The amount used is selected from the range of 0.1 to 1000 times, preferably 1 to 100 times the weight ratio of the substrate α, β-unsaturated aldehydes.

  In the method of the present invention, since the specific catalyst is used, the oxidation reaction can be carried out effectively, and the corresponding α, β-unsaturated carboxylic acids can be produced in a high yield. In addition, the reaction operation is simple, the influence and toxicity to the environment and the human body are small, the effect of reducing the burden on the environment, and α, β-unsaturated carboxylic acids can be obtained safely and rapidly.

  The reaction conditions for the process of the present invention are not particularly limited, but the reaction is usually carried out in the range of -40 to 80 ° C, preferably 0 to 40 ° C.

  The reaction time in the production method of the present invention depends on the amount of catalyst used, the reaction temperature, etc., and cannot be generally defined, but is usually in the range of 1 to 80 hours, preferably in the range of 10 to 30 hours. Is called.

  Α, β-unsaturated carboxylic acids obtained by the method of the present invention include, for example, trans-2-decenoic acid, trans-2-octenoic acid, trans-2-hexenoic acid, 3-methylcrotonic acid, gellanic acid, benzoic acid And cinnamic acid.

  In a general embodiment of the present invention, a metal salt containing iron, an alkali metal salt of carboxylic acid, and a solvent are mixed in a reactor, and an α, β-unsaturated aldehyde is added and reacted at a predetermined temperature. Is to do. After completion of the reaction, the solvent is distilled off, and the obtained α, β-unsaturated carboxylic acid can be taken out by a usual method such as distillation, chromatographic separation, recrystallization or sublimation. If necessary, after completion of the reaction, an organic solvent and dilute hydrochloric acid may be added and separated into an organic layer and an aqueous layer, and then only the organic layer may be separated and concentrated.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further more concretely, this invention is not restrict | limited to a following example.

Example 1
In a test tube, iron nitrate (III) nonahydrate (manufactured by Wako Pure Chemical Industries), 4.1 mg (0.010 mol), sodium acetate (manufactured by Wako Pure Chemical Industries, Ltd.), 16.4 mg (0.20 mmol), ethyl acetate 1 mL (manufactured by Wako Pure Chemical Industries, Ltd.) and 167 mg (1.0 mmol) of trans-2-decenal (manufactured by Tokyo Chemical Industry Co., Ltd.) were added and stirred at 25 ° C. for 16 hours under 1 atmosphere of oxygen. Thereafter, 1M hydrochloric acid (1 mL) was added, and the mixture was extracted three times with ethyl acetate (3 mL). As an internal standard, 31 mg (0.20 mmol) of biphenyl (manufactured by Tokyo Chemical Industry Co., Ltd.) was added and concentrated. A portion was dissolved in deuterated chloroform and subjected to ¹ H NMR measurement. The conversion of trans-2-decenal Was 99%, the yield of trans-2-decenoic acid was 74%, and the selectivity was 75%.

The conversion rate, yield, and selectivity were calculated by the following calculation formula based on the results of analysis by ¹ H NMR.
Conversion rate (%) = (1−number of moles of raw material remaining / number of moles of raw material used) × 100
Yield (%) = (number of moles of target compound / number of moles of starting material used) × 100
Selectivity (%) = yield (%) / conversion (%) × 100

Comparative Example 1
The reaction was carried out under the conditions of Example 1 without adding iron (III) nitrate nonahydrate and sodium acetate. As a result, the conversion rate of trans-2-decenal was 0%.

Comparative Example 2
The reaction was performed under the conditions of Example 1 without adding sodium acetate. The conversion rate of trans-2-decenal was 99%, the yield of trans-2-decenoic acid was 49%, and the selectivity was 49%.

Example 2
In a test tube, iron (III) nitrate nonahydrate (manufactured by Wako Pure Chemical Industries, Ltd.) 4.1 mg (0.010 mol), sodium trifluoroacetate (manufactured by Tokyo Chemical Industry Co., Ltd.) 28 mg (0.20 mmol), ethyl acetate ( 1 mL of Wako Pure Chemical Industries, Ltd.) and 167 mg (1.0 mmol) of trans-2-decenal (Tokyo Chemical Industry Co., Ltd.) were added, and the mixture was stirred at 25 ° C. for 16 hours under 1 atmosphere of oxygen. Thereafter, 1M hydrochloric acid (1 mL) was added, and the mixture was extracted three times with ethyl acetate (3 mL). As an internal standard, 31 mg (0.20 mmol) of biphenyl (manufactured by Tokyo Chemical Industry Co., Ltd.) was added and concentrated. A portion was dissolved in deuterated chloroform and subjected to ¹ H NMR measurement. The conversion of trans-2-decenal Was 98%, the yield of trans-2-decenoic acid was 80%, and the selectivity was 82%.

Example 3
In a test tube, iron nitrate (III) nonahydrate (manufactured by Wako Pure Chemical Industries, Ltd.) 4.1 mg (0.010 mol), potassium acetate (manufactured by Nacalai Tesque) 19.8 mg (0.20 mmol), ethyl acetate (Japanese 1 mL of Kojun Pharmaceutical Co., Ltd.) and 167 mg (1.0 mmol) of trans-2-decenal (Tokyo Chemical Industry Co., Ltd.) were added and stirred at 25 ° C. for 16 hours under 1 atmosphere of oxygen. Thereafter, 1M hydrochloric acid (1 mL) was added, and the mixture was extracted three times with ethyl acetate (3 mL). As an internal standard, 31 mg (0.20 mmol) of biphenyl (manufactured by Tokyo Chemical Industry Co., Ltd.) was added and concentrated. A portion was dissolved in deuterated chloroform and subjected to ¹ H NMR measurement. The conversion of trans-2-decenal Was 74%, the yield of trans-2-decenoic acid was 63%, and the selectivity was 85%.

Example 4
In a test tube, iron (III) nitrate nonahydrate (manufactured by Wako Pure Chemical Industries, Ltd.) 4.1 mg (0.010 mol), potassium trifluoroacetate (manufactured by Tokyo Chemical Industry Co., Ltd.) 31.5 mg (0.20 mmol), acetic acid 1 mL of ethyl (manufactured by Wako Pure Chemical Industries, Ltd.) and 167 mg (1.0 mmol) of trans-2-decenal (manufactured by Tokyo Chemical Industry Co., Ltd.) were added and stirred at 25 ° C. for 16 hours under 1 atmosphere of oxygen. Thereafter, 1M hydrochloric acid (1 mL) was added, and the mixture was extracted three times with ethyl acetate (3 mL). As an internal standard, 31 mg (0.20 mmol) of biphenyl (manufactured by Tokyo Chemical Industry Co., Ltd.) was added and concentrated. A portion was dissolved in deuterated chloroform and subjected to ¹ H NMR measurement. The conversion of trans-2-decenal Was 96%, the yield of trans-2-decenoic acid was 84%, and the selectivity was 87%.

Example 5
In a test tube, anhydrous iron acetate (II) (manufactured by ALDRICHI) 1.7 mg (0.010 mmol), sodium trifluoroacetate (manufactured by Tokyo Chemical Industry Co., Ltd.) 28 mg (0.20 mmol), ethyl acetate (Wako Pure Chemical Industries, Ltd.) 1 mL, trans-2-decenal (manufactured by Tokyo Chemical Industry Co., Ltd.) 167 mg (1.0 mmol) was added, and the mixture was stirred at 25 ° C. for 16 hours under 1 atmosphere of oxygen. 1M hydrochloric acid (1 mL) was added, and the mixture was extracted 3 times with ethyl acetate (3 mL). As a result of gas chromatography measurement of the organic layer, the conversion of trans-2-decenal was 99%, the yield of trans-2-decenoic acid was 82%, and the selectivity was 83%.

Example 6
In a test tube, iron (III) nitrate nonahydrate (manufactured by Wako Pure Chemical Industries, Ltd.) 4.1 mg (0.010 mol), sodium trifluoroacetate (manufactured by Tokyo Chemical Industry Co., Ltd.) 28 mg (0.20 mmol), ethyl acetate ( 1 mL of Wako Pure Chemical Industries, Ltd.) and 167 mg (1.0 mmol) of trans-2-decenal (Tokyo Chemical Industry Co., Ltd.) were added, and the mixture was stirred at 25 ° C. for 16 hours under 1 atmosphere of air. Thereafter, 1M hydrochloric acid (1 mL) was added, and the mixture was extracted three times with ethyl acetate (3 mL). As an internal standard, 31 mg (0.20 mmol) of biphenyl (manufactured by Tokyo Kasei Kogyo Co., Ltd.) was added and concentrated. A portion was dissolved in deuterated chloroform and ¹ H NMR measurement was conducted. The conversion rate of trans-2-decenal was determined. Was 83%, the yield of trans-2-decenoic acid was 73%, and the selectivity was 88%.

Example 7
In a test tube, iron (III) nitrate nonahydrate (manufactured by Wako Pure Chemical Industries, Ltd.) 4.1 mg (0.010 mol), sodium trifluoroacetate (manufactured by Tokyo Chemical Industry Co., Ltd.) 28 mg (0.20 mmol), trans-2 -167 mg (1.0 mmol) of Decenal (Tokyo Kasei Kogyo Co., Ltd.) was added, and the mixture was stirred at 25 ° C for 16 hours under 1 atmosphere of oxygen under the absence of solvent. Thereafter, 1M hydrochloric acid (1 mL) was added, and the mixture was extracted three times with ethyl acetate (3 mL). As an internal standard, 31 mg (0.20 mmol) of biphenyl (manufactured by Tokyo Chemical Industry Co., Ltd.) was added and concentrated. A portion was dissolved in deuterated chloroform and subjected to ¹ H NMR measurement. The conversion of trans-2-decenal Was 90%, the yield of trans-2-decenoic acid was 73%, and the selectivity was 81%.

Example 8
In a test tube, iron (III) nitrate nonahydrate (manufactured by Wako Pure Chemical Industries, Ltd.) 4.1 mg (0.010 mol), sodium trifluoroacetate (manufactured by Tokyo Chemical Industry Co., Ltd.) 28 mg (0.20 mmol), ethyl acetate ( 0.5 mL of Wako Pure Chemical Industries, Ltd.) and 167 mg (1.0 mmol) of trans-2-decenal (Tokyo Chemical Industry Co., Ltd.) were added and stirred at 25 ° C. for 16 hours under 1 atmosphere of oxygen. Thereafter, 1M hydrochloric acid (1 mL) was added, and the mixture was extracted three times with ethyl acetate (3 mL). As an internal standard, 31 mg (0.20 mmol) of biphenyl (manufactured by Tokyo Chemical Industry Co., Ltd.) was added and concentrated. A portion was dissolved in deuterated chloroform and subjected to ¹ H NMR measurement. The conversion of trans-2-decenal Was 87%, the yield of trans-2-decenoic acid was 84%, and the selectivity was 97%.

Example 9
In the same manner as in Example 8, various α, β-unsaturated aldehydes were oxidized. The results are also shown in Table-1.

Claims (4)

  α, β-unsaturated carboxylic acids characterized by oxidation reaction of α, β-unsaturated aldehydes with oxygen or air in the presence of iron (II) or iron (III) salts and alkali metal salts of carboxylic acids A method for producing acids.   The method for producing an α, β-unsaturated carboxylic acid according to claim 1, wherein iron (II) acetate or iron (III) nitrate is used as the iron (II) or iron (III) salt.   3. The α according to claim 1, wherein the alkali metal salt of the carboxylic acid is sodium acetate, potassium acetate, sodium trifluoroacetate, or potassium trifluoroacetate alone or in combination of two or more. , Process for producing β-unsaturated carboxylic acids.   The method for producing an α, β-unsaturated carboxylic acid according to any one of claims 1 to 3, wherein the oxidation reaction is performed in the presence of an organic solvent.