JP2016222713A - METHOD FOR PRODUCING β-KETOCARBOXYLIC ACID SILVER - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing β-ketocarboxylic acid silver of high quality at a high yield by a simple process.SOLUTION: Provided is a method for producing β-ketocarboxylic acid silver comprising: a step where a β-ketocarboxylic acid salt represented by the general formula (II) is produced; a step where an aqueous solution including the produced β-ketocarboxylic acid salt and nitric acid are mixed so as to make the aqueous solution acid; a step where the aqueous solution made acid and silver nitrate are mixed to produce the β-ketocarboxylic acid silver represented by the general formula (I); and a step where the produced β-ketocarboxylic acid silver is discharged, in which, after the step of making the aqueous solution acid, till the step of discharging the β-ketocarboxylic acid silver, a step of charging the seed crystals of the β-ketocarboxylic acid silver is included, and the step of charging the seed crystals is performed between the stage till 10 min before from the start of the mixture between the aqueous solution made into acid and the silver nitrate and the stage after 10 min upon the completion of the mixing of the aqueous solution made into acid and the silver nitrate.SELECTED DRAWING: None

Description

  The present invention relates to a method for producing silver β-ketocarboxylate.

  Metallic silver is widely used as a recording material and printing plate material, and as a highly conductive material because of its excellent conductivity. As a general method for producing metallic silver, for example, a method of heating silver oxide which is an inorganic substance in the presence of a reducing agent can be mentioned. Specifically, for example, a particulate silver oxide is dispersed in a binder, a reducing agent is added thereto to prepare a paste, and the paste is applied to a substrate or the like and heated. Thus, by heating in the presence of a reducing agent, the silver oxide is reduced, the metallic silver produced by the reduction is fused together, and a film containing metallic silver is formed.

  However, when silver oxide is used as a material for forming metallic silver, a reducing agent is required, and there is a problem that the heating temperature is as high as about 300 ° C. Further, when metallic silver is used as the conductive material, it is necessary to use finer silver oxide particles in order to reduce the resistance of the formed film.

On the other hand, in recent years, a method for forming metallic silver using organic acid silver in place of the inorganic material as described above has also been reported. As such organic acid silver, for example, silver behenate, silver stearate, and silver α-ketocarboxylate have been reported (see Patent Documents 1 to 3).
However, when silver behenate is used, there is a problem that heating in the presence of a reducing agent is necessary to form metallic silver. In addition, when using silver stearate or silver α-ketocarboxylate, it is lower than when using an inorganic substance, but heating at about 210 ° C. or more is necessary to form metallic silver quickly. There was a problem.

  In recent years, a method for heating silver β-ketocarboxylate represented by the following general formula (1) has been disclosed as a method for producing metallic silver that solves these problems (see Patent Document 4). This method of using silver β-ketocarboxylate is an extremely excellent method in that a reducing agent is not required and metal silver having excellent characteristics can be formed at a heating temperature lower than that in the past.

（前記式（１）において、Ｒは、直鎖、分枝もしくは環状の飽和もしくは不飽和Ｃ_１〜Ｃ_２０脂肪族炭化水素基、Ｒ^１−ＣＹ_２−、ＣＹ_３−、Ｒ^１−ＣＨＹ−、Ｒ^２Ｏ−、フェニル基、１個もしくは複数の置換基で置換されたフェニル基、Ｒ^５Ｒ^４Ｎ−、水酸基（−ＯＨ）、アミノ基（−ＮＨ_２）、または、（Ｒ^３Ｏ）_２ＣＹ−である。
ただし、Ｙは、同一であるかまたは異なり、それぞれフッ素原子、塩素原子、臭素原子または水素原子であり、Ｒ^１は直鎖、分枝または環状の飽和または不飽和Ｃ_１〜Ｃ_１９脂肪族炭化水素基、または、フェニル基であり、Ｒ^２は直鎖、分枝または環状の飽和または不飽和Ｃ_１〜Ｃ_２０脂肪族炭化水素基であり、Ｒ^３は直鎖、分枝または環状の飽和または不飽和Ｃ_１〜Ｃ_１６脂肪族炭化水素基であり、Ｒ^４およびＲ^５は、同一であるかまたは異なり、それぞれ直鎖、分枝または環状の飽和または不飽和Ｃ_１〜Ｃ_１８脂肪族炭化水素基である。
前記式（１）において、Ｘは、同一であるかまたは異なり、それぞれ水素原子、直鎖、分枝または環状の飽和または不飽和Ｃ_１〜Ｃ_２０脂肪族炭化水素基、Ｒ^６Ｏ−、Ｒ^６Ｓ−、Ｒ^６−ＣＯ−、Ｒ^６−ＣＯ−Ｏ−、ハロゲン（フッ素、塩素、臭素、ヨウ素）、ベンジル基、フェニル基、１個もしくは複数の置換基で置換されたフェニル基もしくはベンジル基、シアノ基（−Ｃ≡Ｎ）、Ｎ−フタロイル−３−アミノプロピル基、２−エトキシビニル基（Ｃ_２Ｈ_５−Ｏ−ＣＨ＝ＣＨ−）である。
ただし、Ｒ^６は直鎖、分枝もしくは環状の飽和もしくは不飽和Ｃ_１〜Ｃ_１０脂肪族炭化水素基、チオフェン基（Ｃ_４Ｈ_３Ｓ−）、フェニル基、ジフェニル基、または、１個もしくは複数の置換基で置換されたフェニル基もしくはジフェニル基である。）

In (Formula (1), R is a straight-chain, saturated or unsaturated _C 1 branched or cyclic _{-C 20} aliphatic hydrocarbon ^{_{group, R 1 -CY 2 -, CY}} 3 -, R 1 -CHY- , R ² O—, a phenyl group, a phenyl group substituted with one or more substituents, R ⁵ R ⁴ N—, a hydroxyl group (—OH), an amino group (—NH ₂ ), or (R ³ O ) ₂ CY-.
However, Y is the same or different, and is respectively a fluorine atom, a chlorine atom, a bromine atom, or a hydrogen atom, and R ¹ is a linear, branched or cyclic saturated or unsaturated C _{1 to} C ₁₉ aliphatic carbonization. A hydrogen group or a phenyl group, R ² is a linear, branched or cyclic saturated or unsaturated C _{1 to} C ₂₀ aliphatic hydrocarbon group, and R ³ is a linear, branched or cyclic saturated group. or unsaturated _C 1 _{-C 16} aliphatic hydrocarbon radical, ^{R 4} and ^{R 5,} which are identical or different, each a straight-chain, branched or cyclic saturated or unsaturated _C 1 _{-C 18} aliphatic It is a hydrocarbon group.
In the formula (1), X is the same or different and each represents a hydrogen atom, a linear, branched or cyclic saturated or unsaturated C _{1 to} C ₂₀ aliphatic hydrocarbon group, R ⁶ O—, R ⁶ S-, R ⁶ -CO-, R ⁶ -CO-O-, halogen (fluorine, chlorine, bromine, iodine), benzyl group, phenyl group, phenyl group or benzyl substituted with one or more substituents Group, cyano group (—C≡N), N-phthaloyl-3-aminopropyl group, and 2-ethoxyvinyl group (C ₂ H ₅ —O—CH═CH—).
Where R ⁶ is a linear, branched or cyclic saturated or unsaturated C _{1 to} C ₁₀ aliphatic hydrocarbon group, thiophene group (C ₄ H ₃ S—), phenyl group, diphenyl group, or one or A phenyl group or a diphenyl group substituted with a plurality of substituents. )

  Among the methods for producing β-ketocarboxylate specifically described in Patent Document 4, it has been confirmed that the obtained β-ketocarboxylate is specifically useful as a material for forming metallic silver. The manufacturing method is as follows. That is, a β-ketocarboxylate ester in which the group represented by the formula “—OAg” bonded to the carbonyl group of the β-ketocarboxylate silver represented by the formula (1) is substituted with an alkoxy group is used as a base. The product is hydrolyzed under neutral conditions to produce β-ketocarboxylic acid, and then the reaction solution is washed by ether extraction, then diluted sulfuric acid or concentrated sulfuric acid is added to extract and wash, and diethanolamine is added to adjust pH. This is only a production method including a step of adding silver nitrate to produce the silver β-ketocarboxylate after extraction washing.

JP 2003-191646 A Japanese Patent Laid-Open No. 10-183207 JP 2004-315374 A International Publication No. 2007/004437

  However, the production method described in Patent Document 4 has a problem that the production process is complicated, although silver β-ketocarboxylate more useful as a material for forming metallic silver can be obtained. In addition, for example, at the time of extraction washing after the addition of diethanolamine, there is a problem that separation of the aqueous layer and the organic layer does not proceed cleanly and each process takes a long time. In addition, the separation of impurities from the target product may be insufficient. As a result, for example, the impurity content in silver β-ketocarboxylate increases, or it takes a long time to dry silver β-ketocarboxylate. There were problems such as that. And there existed a problem that the yield of (beta) -ketocarboxylic acid silver might fall. Thus, conventionally, there has been no actual method for producing high-quality silver β-ketocarboxylate in a simple process with high yield.

  This invention is made | formed in view of the said situation, and makes it a subject to provide the method of manufacturing a high quality silver (beta) -ketocarboxylate with a simple process with sufficient yield.

To solve the above problem,
The present invention comprises a step of producing a β-ketocarboxylate represented by the following general formula (II), an aqueous solution containing the produced β-ketocarboxylate and nitric acid, thereby acidifying the aqueous solution. Mixing the acidified aqueous solution and silver nitrate to produce silver β-ketocarboxylate represented by the following general formula (I), and taking out the produced silver β-ketocarboxylate And a method of producing a silver β-ketocarboxylate having a seed crystal of the β-ketocarboxylate after the step of acidifying the aqueous solution and before the step of taking out the silver β-ketocarboxylate The step of adding the seed crystal to the step of 10 minutes before the start of mixing of the aqueous solution and silver nitrate made acidic, and the end of mixing of the aqueous solution and silver nitrate made acidic. 10 minutes from To provide a method of manufacturing a β- ketocarboxylic acid silver and performing between stages up.

（式中、Ｒ^ａは炭素数１〜２０の直鎖状若しくは分枝鎖状のアルキル基又はフェニル基であり；Ｘ^ａは水素原子又は炭素数１〜２０の直鎖状若しくは分枝鎖状のアルキル基であり、二つのＸ^ａは互いに同一でも異なっていてもよく；Ｍ^＋はナトリウムイオン、カリウムイオン又はリチウムイオンである。）

(In the formula, R ^a is ^a linear or branched alkyl group having 1 to 20 carbon atoms or ^a phenyl group; X ^a is a hydrogen atom or linear or branched chain having 1 to 20 carbon atoms; And the two X ^{a s} may be the same or different from each other; M ⁺ is a sodium ion, a potassium ion or a lithium ion.)

In the method for producing silver β-ketocarboxylate of the present invention, when using the acidified aqueous solution or the silver nitrate as an aqueous solution, the seed crystal is preferably introduced into the silver nitrate aqueous solution.
The method for producing silver β-ketocarboxylate of the present invention preferably includes a step of allowing an inert gas to flow into the acidified aqueous solution before mixing with the silver nitrate.
The method for producing silver β-ketocarboxylate of the present invention preferably includes a step of filtering the acidified aqueous solution before mixing with the silver nitrate.
In the method for producing a silver β-ketocarboxylate according to the present invention, the step of producing the β-ketocarboxylate salt is represented by the following general formula (III) using sodium hydroxide, potassium hydroxide or lithium hydroxide. It is preferable to have a step of hydrolyzing the β-ketocarboxylic acid ester.

（式中、Ｒ^ａは炭素数１〜２０の直鎖状若しくは分枝鎖状のアルキル基又はフェニル基であり；Ｒ^ｂは炭素数１〜５の直鎖状若しくは分岐鎖状のアルキル基又はベンジル基であり；Ｘ^ａは水素原子又は炭素数１〜２０の直鎖状若しくは分枝鎖状のアルキル基であり、二つのＸ^ａは互いに同一でも異なっていてもよい。）

Wherein R ^a is ^a linear or branched alkyl group having 1 to 20 carbon atoms or a phenyl group; R ^b is a linear or branched alkyl group having 1 to 5 carbon atoms or X ^a is a hydrogen atom or ^a linear or branched alkyl group having 1 to 20 carbon atoms, and the two X ^a may be the same or different from each other.

In the method for producing a silver β-ketocarboxylate of the present invention, the ^Ra is ^a linear or branched alkyl group having 1 to 5 carbon atoms or a phenyl group, and the ^Xa is a hydrogen atom or a carbon number. It is preferably 1 to 3 linear or branched alkyl groups.

  According to the present invention, high-quality silver β-ketocarboxylate can be produced with high yield by a simple process.

It is a figure which shows the FT-IR spectrum of 2-methylacetoacetate silver obtained in Examples 2-5 and Reference Example 1. It is a figure which shows the FT-IR spectrum of 2-methylacetoacetate silver obtained in Reference Example 1 and Comparative Example 1.

  The method for producing a silver β-ketocarboxylate according to the present invention comprises a step of producing a β-ketocarboxylate represented by the following general formula (II) (hereinafter abbreviated as “β-ketocarboxylate (II)”). The aqueous solution containing the produced β-ketocarboxylate (II) and nitric acid are mixed to make the aqueous solution acidic, the acidic aqueous solution and silver nitrate are mixed, and the following general formula (I) And a step of producing a silver β-ketocarboxylate (hereinafter abbreviated as “β-ketocarboxylic acid silver (I)”) and a step of taking out the produced silver β-ketocarboxylate (I). A method for producing a silver β-ketocarboxylate having a seed crystal of silver β-ketocarboxylate (I) after the step of acidifying the aqueous solution and before the step of taking out the silver (I) of β-ketocarboxylate It has a process to input To.

（式中、Ｒ^ａは炭素数１〜２０の直鎖状若しくは分枝鎖状のアルキル基又はフェニル基であり；Ｘ^ａは水素原子又は炭素数１〜２０の直鎖状若しくは分枝鎖状のアルキル基であり、二つのＸ^ａは互いに同一でも異なっていてもよく；Ｍ^＋はナトリウムイオン、カリウムイオン又はリチウムイオンである。）

(In the formula, R ^a is ^a linear or branched alkyl group having 1 to 20 carbon atoms or ^a phenyl group; X ^a is a hydrogen atom or linear or branched chain having 1 to 20 carbon atoms; And the two X ^{a s} may be the same or different from each other; M ⁺ is a sodium ion, a potassium ion or a lithium ion.)

[Step of producing β-ketocarboxylate (II)]
The method for producing a β-ketocarboxylate of the present invention includes a step of producing a β-ketocarboxylate (II) (hereinafter abbreviated as “β-ketocarboxylate (II) production step”).
In the formula, R ^a is ^a linear or branched alkyl group having 1 to 20 carbon atoms or a phenyl group, and examples of the alkyl group include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, n -Butyl group, isobutyl group, sec-butyl group, tert-butyl group, n-pentyl group, isopentyl group, neopentyl group, tert-pentyl group, 1-methylbutyl group, n-hexyl group, 2-methylpentyl group, 3 -Methylpentyl group, 2,2-dimethylbutyl group, 2,3-dimethylbutyl group, 2-methylhexyl group, 3-methylhexyl group, 2,2-dimethylpentyl group, 2,3-dimethylpentyl group, 2 , 4-dimethylpentyl group, 3,3-dimethylpentyl group, 3-ethylpentyl group, 2,2,3-trimethylbutyl group, n-octyl group, isooctyl And a nonyl group, a nonyl group, a decyl group, an undecyl group, a dodecyl group, a tridecyl group, a tetradecyl group, a pentadecyl group, a hexadecyl group, a heptadecyl group, an octadecyl group, a nonadecyl group, and an icosyl group.
Especially, it is preferable that R ^<a> is a C1-C10 alkyl group or a phenyl group, and it is more preferable that it is a C1-C5 alkyl group or a phenyl group.

In the formula, X ^a is a hydrogen atom or ^a linear or branched alkyl group having 1 to 20 carbon atoms, and the alkyl group is a linear or branched chain having 1 to 20 carbon atoms in R ^a . It is the same as the alkyl group having a shape. Further, the two X ^a may be the same or different from each other, a combination of the two X ^a where are different is not particularly limited.
Among these, X ^a is preferably a hydrogen atom or an alkyl group having 1 to 10 carbon atoms, more preferably a hydrogen atom or an alkyl group having 1 to 5 carbon atoms, and a hydrogen atom or an alkyl group having 1 to 3 carbon atoms. Are more preferable, and a hydrogen atom, a methyl group or an ethyl group is particularly preferable.
X ^a is preferably at least one is a hydrogen atom.

In the formula, M ⁺ is a sodium ion, a potassium ion or a lithium ion, preferably a sodium ion or a potassium ion.

The method for producing the β-ketocarboxylate (II) is not particularly limited, and a known method may be applied. Among them, a preferable method is β- in which a group represented by the formula “—O ⁻ M ⁺ ” bonded to the carbonyl group of β-ketocarboxylate (II) is substituted with an alkoxy group or an aralkyloxy group. A method including the step of converting an ester into a carboxylate by hydrolyzing the ester bond of a ketocarboxylic acid ester under basic conditions can be exemplified. And it is preferable to use the aqueous solution obtained by hydrolysis for the next process as an aqueous solution containing β-ketocarboxylate (II) as it is. That is, the β-ketocarboxylate (II) production step preferably includes a step of hydrolyzing the β-ketocarboxylic acid ester using a base.
The alkoxy group preferably has 1 to 5 carbon atoms. The aralkyloxy group is preferably a benzyloxy group, a phenethyloxy group, a 1-naphthylmethyloxy group, a 2-naphthylmethyloxy group, a 1-naphthylethyloxy group, or a 2-naphthylethyloxy group.

  The β-ketocarboxylic acid ester is preferably one represented by the following general formula (III) (hereinafter abbreviated as β-ketocarboxylic acid ester (III)).

（式中、Ｒ^ａは炭素数１〜２０の直鎖状若しくは分枝鎖状のアルキル基又はフェニル基であり；Ｒ^ｂは炭素数１〜５の直鎖状若しくは分岐鎖状のアルキル基又はベンジル基であり；Ｘ^ａは水素原子又は炭素数１〜２０の直鎖状若しくは分枝鎖状のアルキル基であり、二つのＸ^ａは互いに同一でも異なっていてもよい。）

Wherein R ^a is ^a linear or branched alkyl group having 1 to 20 carbon atoms or a phenyl group; R ^b is a linear or branched alkyl group having 1 to 5 carbon atoms or X ^a is a hydrogen atom or ^a linear or branched alkyl group having 1 to 20 carbon atoms, and the two X ^a may be the same or different from each other.

^Wherein, R a, ^{X a} is the same as ^R a, ^{X a} in the formula (I) and (II).
In the formula, R ^b is a linear or branched alkyl group having 1 to 5 carbon atoms or a benzyl group (—CH ₂ —C ₆ H ₅ ), and examples of the alkyl group include a methyl group, an ethyl group, Examples include n-propyl group, isopropyl group, n-butyl group, isobutyl group, sec-butyl group, tert-butyl group, n-pentyl group, isopentyl group, neopentyl group, tert-pentyl group and 1-methylbutyl group. Among these, R ^b is preferably an alkyl group having 1 to 3 carbon atoms or a benzyl group, and more preferably a methyl group, an ethyl group, an isopropyl group, or a benzyl group.

  The β-ketocarboxylic acid ester (III) to be subjected to hydrolysis may be one kind or two or more kinds, but usually one kind is preferable in that the process can be simplified.

The base used in the hydrolysis is preferably one containing a metal atom (metal ion) corresponding to M ⁺ so as to obtain a β-ketocarboxylate (II), more preferably an inorganic base, sodium hydroxide, water More preferred is potassium oxide or lithium hydroxide, and particularly preferred is sodium hydroxide or potassium hydroxide.
The base to be used may be one kind or two or more kinds, but usually one kind is sufficient.

The amount of the base used may be set as appropriate according to the hydrolysis conditions, but is preferably 1 to 2.5 mol with respect to 1 mol of β-ketocarboxylic acid ester (III), More preferably, it is a mole.
The base is preferably added as an aqueous solution, and the concentration of the base in the aqueous solution is preferably 5 to 30% by mass.

  The solvent used in the hydrolysis is preferably water or a mixed solvent of water and an organic solvent, and may be appropriately selected depending on the type of β-ketocarboxylic acid ester (III). The organic solvent in the mixed solvent is not particularly limited as long as it does not hinder the hydrolysis reaction.

  The concentration of β-ketocarboxylic acid ester (III) in the reaction solution at the start of hydrolysis may be appropriately adjusted according to other reaction conditions, but is preferably 0.5 to 5 mol / L.

The temperature during hydrolysis is preferably 5 to 35 ° C.
Moreover, it is preferable that the reaction time of a hydrolysis is 3 to 24 hours.

  The aqueous solution containing the β-ketocarboxylate (II) after hydrolysis is usually basic, and the pH of the aqueous solution is not particularly limited as long as the β-ketocarboxylate (II) is stably present.

[Step of mixing aqueous solution containing β-ketocarboxylate (II) and nitric acid to make the aqueous solution acidic]
The method for producing a silver β-ketocarboxylate according to the present invention further comprises a step of acidifying the aqueous solution by mixing an aqueous solution containing the produced β-ketocarboxylate (II) and nitric acid (hereinafter referred to as “acidification”). Abbreviated as "process"). In this step, β-ketocarboxylate (II) (R ^a —C (═O) —CX ^a ₂ —C (═O) —O ^— M ⁺ ) is converted to β-ketocarboxylic acid (R ^a —C ( = O) -CX ^a ₂ -C (= O) -OH), and β-ketocarboxylate (II) is considered to exist more stably.
In the present invention, as described above, after the β-ketocarboxylate (II) is formed, the β-ketocarboxylate (II) is included in the aqueous solution. It is possible to make this aqueous solution acidic by mixing this aqueous solution and nitric acid without extracting and removing by-products from the reaction solution (aqueous solution) containing II). Here, examples of the “by-product” include impurities generated when β-ketocarboxylate (II) is formed or when β-ketocarboxylate (II) is contained in an aqueous solution. it can. For example, when the β-ketocarboxylate (II) production step includes a step of hydrolyzing the β-ketocarboxylate ester (III), the β-ketocarboxylate ester (III) falls under “by-product”. do not do.

  Examples of a method of mixing an aqueous solution containing β-ketocarboxylate (II) and nitric acid include a method of adding nitric acid to the aqueous solution and a method of adding the aqueous solution to nitric acid, and adding nitric acid to the aqueous solution. The method is preferred.

  The pH of the acidic aqueous solution after mixing with nitric acid may be less than 7 so that silver oxide is not formed, and it is preferably 3.5 to 6.5 because the converted carboxyl group can exist stably.

  The aqueous solution containing β-ketocarboxylate (II) may contain any component other than β-ketocarboxylate (II) within a range not impairing the effects of the present invention. For example, when the β-ketocarboxylate (II) production step includes a step of hydrolyzing β-ketocarboxylate ester (III), the aqueous solution may contain a base used for hydrolysis.

  The β-ketocarboxylate (II) contained in the aqueous solution may be one kind or two or more kinds. In the case of two or more kinds, the combination and ratio can be arbitrarily adjusted.

  The amount of nitric acid mixed with the aqueous solution containing the β-ketocarboxylate (II) is not particularly limited as long as the pH of the aqueous solution after mixing with nitric acid is adjusted to a desired value. For example, when the β-ketocarboxylate (II) is obtained by a method having a step of hydrolyzing the β-ketocarboxylate (III), the amount of nitric acid used is β-ketocarboxylate (III) It is preferable that it is 0.03-2 mol with respect to 1 mol, and it is more preferable that it is 0.04-1.2 mol.

The temperature of the reaction solution during mixing with nitric acid is preferably 0 to 20 ° C, and more preferably 3 to 15 ° C.
Nitric acid is preferably added dropwise to an aqueous solution containing β-ketocarboxylate (II) as an aqueous solution.
The concentration of the aqueous nitric acid solution during mixing is preferably 3 to 80% by mass.
The reaction time after mixing with nitric acid may be adjusted so as to maximize the production amount of the target product (β-ketocarboxylic acid), and is not particularly limited. For example, the reaction time may be as short as about 10 to 30 minutes. .

[Step of mixing acidified aqueous solution and silver nitrate to produce silver (I) β-ketocarboxylate]
In the method for producing silver β-ketocarboxylate of the present invention, the acidified aqueous solution and silver nitrate are further mixed to produce silver β-ketocarboxylate (I) (hereinafter referred to as “silver β-ketocarboxylate ( I) abbreviated as “generation step”. In this step, β-ketocarboxylic acid salt which is in an equilibrium relationship with β-ketocarboxylic acid (R ^a —C (═O) —CX ^a ₂ —C (═O) —OH) and exists more stably. (II) (R ^a —C (═O) —CX ^a ₂ —C (═O) —O ^— M ⁺ ) is converted to silver β-ketocarboxylate (I) (R ^a —C (═O) —CX ^a _2- C (= O) -OAg).
In the present invention, as described above, after the aqueous solution containing the β-ketocarboxylate (II) is acidified, the aqueous solution and silver nitrate can be mixed without extracting and removing by-products from the aqueous solution. Is possible. Here, examples of the “by-product” include impurities generated when the acidified aqueous solution and silver nitrate are mixed, in addition to those exemplified above.

  Examples of the method of mixing the acidified aqueous solution and silver nitrate include a method of adding silver nitrate to the aqueous solution and a method of adding the aqueous solution to silver nitrate. Silver nitrate is preferably used as an aqueous solution.

  The amount of silver nitrate mixed with the acidic aqueous solution is determined by substituting all the hydrogen atoms in the carboxyl group (-C (= O) -OH) of the β-ketocarboxylic acid with silver atoms to form a carboxyl group (-C (= O ) -OH) is preferably in an amount capable of converting silver carboxylate (-C (= O) -OAg). That is, the amount of silver nitrate used is preferably equimolar or more with β-ketocarboxylic acid. For example, when β-ketocarboxylate (II) is obtained by a method having a step of hydrolyzing β-ketocarboxylate (III), β-ketocarboxylate (II), β- It is preferable to adjust the amount of silver nitrate used in consideration of the reaction rate when the ketocarboxylic acid is obtained, and the amount of silver nitrate used in this case is usually 1 mol of β-ketocarboxylic acid ester (III). On the other hand, it is preferable that it is 0.5-1.7 mol.

The temperature of the reaction solution at the time of mixing silver nitrate is preferably 0 to 20 ° C, and more preferably 3 to 15 ° C.
When using silver nitrate as aqueous solution, it is preferable that the density | concentration of the silver nitrate aqueous solution at the time of mixing is 15-60 mass%. Further, an aqueous solution obtained by dissolving silver nitrate in water is almost neutral (about pH 6 to 7), and this aqueous solution may be used at the time of mixing, but an acidic aqueous solution of silver nitrate obtained by adding an acid separately. May be used. The acid added at this time is preferably nitric acid. Moreover, the pH of the acidic aqueous solution of silver nitrate is not particularly limited, but is preferably 0.5 or more.
The reaction time after mixing the silver nitrate is not particularly limited as long as the production amount of the target product (silver β-ketocarboxylate (I)) is maximized. For example, the reaction time is as short as about 10 to 60 minutes. You can also

[Step of removing the produced silver (I) β-ketocarboxylate]
The method for producing a silver β-ketocarboxylate according to the present invention includes a step of taking out the produced silver (I) of β-ketocarboxylate (hereinafter abbreviated as “takeout step”). What is necessary is just to take out by a well-known method. Then, the taken silver (I) β-ketocarboxylate may be used alone or in combination of two or more operations such as crystallization, reprecipitation, column chromatography, extraction, and stirring and washing of the crystals with a solvent. You may refine | purify by performing once in combination or more.
Moreover, you may perform a post-process as needed before a taking-out process. Here, “post-treatment” refers to operations such as filtration, washing, extraction, pH adjustment, dehydration, and concentration, and any one of these operations may be performed alone or in combination of two or more. Good.

  In the extraction step, the extracted β-ketocarboxylate (I) may be washed with a washing solvent. By washing, it may be possible to improve the quality of the silver (I) β-ketocarboxylate. Furthermore, by selecting an appropriate washing solvent according to the type of silver (I) β-ketocarboxylate, the yield can be improved without impairing the quality.

Preferred examples of the washing solvent include water, alcohol, and ketone.
The alcohol preferably has 1 to 3 carbon atoms, and more preferably methanol, ethanol, or 2-propanol.
The ketone preferably has 3 to 5 carbon atoms, and more preferably acetone.
The said washing | cleaning solvent may be used individually by 1 type, and may use 2 or more types together.

The number of times of washing may be one or two or more, and may be adjusted as appropriate according to the purpose.
When the number of washings is two times or more (multiple times), the washing solvent to be used may be the same at all times, may be different at all times, or may be the same at only some times. Also good.

  The amount of the washing solvent used per washing may be adjusted as appropriate and is not particularly limited, but is preferably 0.2 to 5 mL per 1 g of the theoretical yield of silver (I) β-ketocarboxylate, 0.5 More preferably, it is ˜3 mL.

[Step of introducing seed crystal of silver β-ketocarboxylate (I)]
The method for producing a silver β-ketocarboxylate according to the present invention includes a step of introducing a seed crystal of silver (I) β-ketocarboxylate (hereinafter referred to as “seed crystal charging step”) between the acidification step and the removal step. (Abbreviated). By performing the seed crystal charging step, it is possible to improve the yield of the target silver β-ketocarboxylate (I).
The seed crystal charging step may be performed at any stage from the end of the acidification step until the removal step is performed. That is, after mixing the aqueous solution containing β-ketocarboxylate (II) and nitric acid to acidify the aqueous solution, until the target β-ketocarboxylate silver (I) is taken out, The seed crystal may be charged at any stage. Here, the target to be charged with the seed crystal is a liquid from the end of the acidification step to the removal step. In the β-ketocarboxylate (I) production step, the β-ketocarboxylate (I ) And coexisting liquid.

The seed crystal charging step is preferably performed immediately before mixing the acidified aqueous solution and silver nitrate and immediately after the mixing of the acidified aqueous solution and silver nitrate is completed. By doing so, the amount of the seed crystal that has been introduced can be reduced in the liquid at the destination, and the effect of using the seed crystal can be obtained more remarkably.
Here, “immediately before mixing the acidified aqueous solution and silver nitrate” means a stage from the start of mixing of the acidified aqueous solution and silver nitrate to 10 minutes before, preferably the acidified aqueous solution. It means a stage between the start of mixing with silver nitrate and 5 minutes before the start.
In addition, “immediately after the mixing of the acidified aqueous solution and silver nitrate is completed” means that the acidified aqueous solution and silver nitrate are mixed at a stage between the end of mixing and 10 minutes later, preferably the acidified solution. It means a stage between the end of mixing of the aqueous solution and silver nitrate until 5 minutes later.

For example, the seed crystal is added to any one or more of the acidified aqueous solution, silver nitrate (silver nitrate aqueous solution), and the acidified aqueous solution and silver nitrate (silver nitrate aqueous solution) during or after mixing. it can.
When the seed crystal is added to the acidified aqueous solution, it may be added at any stage before and during mixing with the silver nitrate.
When the seed crystal is added to silver nitrate (silver nitrate aqueous solution), it may be added at any stage before and during mixing with the acidified aqueous solution.

  The amount of the seed crystal used is not particularly limited, and can be appropriately adjusted depending on, for example, the acidified aqueous solution or the silver nitrate aqueous solution. Usually, the amount of the seed crystal is based on the theoretical yield of silver β-ketocarboxylate (I). The amount is preferably 1 to 10% by mass.

  The present inventors have found that the crystal of silver (I) β-ketocarboxylate can be in three crystal forms. One of these three crystal forms is plate-like (hereinafter abbreviated as “A-type”), and in the take-out process, liquid removal is easy, the cleaning effect is high, and high-purity crystals are easily obtained. is there. Another type is needle-shaped (hereinafter abbreviated as “B-type”), and is more difficult to drain than A-type in the removal step. The remaining type is one that does not correspond to either A type or B type (hereinafter abbreviated as “C type”). Among these, the silver β-ketocarboxylate (I) is preferably an A type in terms of quality and production suitability. However, the β-ketocarboxylate (I) is crystallized in a form other than the A type as compared with the conventional production method. Obtained in purity.

  In the present invention, when a seed crystal is used, β-ketocarboxylate (I) having the same crystal type as that of the seed crystal is preferentially precipitated (for example, by using the A-type seed crystal, Since β-ketocarboxylate (I) is preferentially precipitated), the crystal type of the seed crystal may be selected according to the purpose.

[Step of flowing an inert gas into the acidified aqueous solution]
The method for producing silver β-ketocarboxylate according to the present invention comprises a step of flowing an inert gas into the acidified aqueous solution before mixing with the silver nitrate (hereinafter abbreviated as “inert gas inflow step”). It is preferable to have. By performing the inert gas inflow step, A-type crystals of silver (I) β-ketocarboxylate are preferentially obtained. The reason is not clear, but when the amount of carbon dioxide (CO ₂ ) or carbonate ion (CO ₃ ²⁻ ) in the acidified aqueous solution increases, the B-type crystal of silver β-ketocarboxylate (I) has priority. It is presumed that A-type crystals may be obtained preferentially by removing carbon dioxide or carbonate ions that induce B-type crystal form from the acidified aqueous solution. .

The inert gas may be a known one such as nitrogen gas or argon gas.
The method for allowing the inert gas to flow is not particularly limited as long as the inert gas can be bubbled into the acidified aqueous solution, and a known bubbling method can be appropriately employed.
The flow rate of the inert gas, the time during which the inert gas is allowed to flow, and the temperature of the aqueous solution when the inert gas is introduced are adjusted as appropriate according to the amount of the aqueous solution and the amount of carbon dioxide or carbonate ions therein. That's fine. As an example of preferable conditions, the temperature of the said aqueous solution shall be 3-15 degreeC, and the conditions which make an inert gas flow in for 10 to 60 minutes at a flow rate of 1-10 L / min are mentioned.

[Step of filtering the acidified aqueous solution]
The method for producing silver β-ketocarboxylate of the present invention preferably includes a step of filtering the acidified aqueous solution before mixing with the silver nitrate (hereinafter abbreviated as “filtering step”). By performing the filtration step, the A-type crystals of silver β-ketocarboxylate (I) are preferentially obtained. The reason for this is not clear, but when the amount of precipitates in the acidified aqueous solution mixed with silver nitrate increases, B-type crystals of β-ketocarboxylate (I) tend to be preferentially obtained, It is presumed that the A-type crystals may be obtained preferentially by removing the precipitates that induce the B-type crystal form from the acidified aqueous solution. In addition, as said deposit, (beta) -ketocarboxylic acid ester (III) mixed when obtaining (beta) -ketocarboxylic acid salt (II) by the method which has the process of hydrolyzing (beta) -ketocarboxylic acid ester (III) The impurities derived from the source can be exemplified.

  The filter used in the filtration step is not particularly limited as long as it can filter the acidified aqueous solution, and can be arbitrarily selected according to the object to be filtered. Examples of the filter material include resin, paper, and metal, and examples of the filter form include a microfilter, woven fabric, and non-woven fabric.

  In this invention, when performing both an inert gas inflow process and a filtration process, the order which performs these is not specifically limited. However, considering that the acidified aqueous solution may increase the amount of precipitates with the passage of time, considering that it is preferable that the time from the completion of the filtration step to mixing with the silver nitrate is short, It is preferable to perform the filtration step after the inert gas inflow step. For example, when a seed crystal is charged into the acidified aqueous solution, it is preferable to perform a filtration step before the seed crystal is charged.

[Other processes]
The method for producing a silver β-ketocarboxylate of the present invention may have other steps in addition to the above steps as long as the effects of the present invention are not impaired.
Examples of the other steps include a step of adding an organic solvent to the acidified aqueous solution before mixing with the silver nitrate (hereinafter, abbreviated as “organic solvent addition step”). By performing the organic solvent addition step, for example, the precipitate in the aqueous solution that has been acidified can be dissolved. In this case, the same effect as that obtained when the filtration step is performed can be obtained.
The kind and amount of the organic solvent to be added may be appropriately selected according to the kind and amount of the precipitate, and are not particularly limited. Preferred organic solvents include alcohols such as ethanol and ketones such as methyl ethyl ketone.

Examples of the other steps include a liquid containing β-ketocarboxylate (I) and a β-ketocarboxylate (I) containing β-ketocarboxylate (I). A step of adding a poor solvent of β-ketocarboxylate (I) (hereinafter abbreviated as “poor solvent addition step”) to the mixed solution produced in the production step) may be mentioned. Here, the “poor solvent of β-ketocarboxylate silver (I)” means a solvent having low solubility of silver β-ketocarboxylate (I).
Examples of the poor solvent include alcohol and ketone.
The alcohol preferably has 1 to 3 carbon atoms, and more preferably methanol, ethanol, or 2-propanol.
The ketone is preferably acetone.
A poor solvent may be used individually by 1 type, and may use 2 or more types together.

  The amount of the poor solvent used may be appropriately adjusted and is not particularly limited, but is preferably 0.4 to 10 mL, preferably 0.8 to 5 mL per 1 g of the theoretical yield of silver β-ketocarboxylate (I). Is more preferable.

  In addition, as the other steps, for example, when β-ketocarboxylate (II) is obtained by a method having a step of hydrolyzing β-ketocarboxylate (III), β-ketocarboxylate You may have the process of removing the alcohol and unreacted raw material which were produced | generated by the said hydrolysis in any step before an acid silver (I) production | generation process. The removal of the alcohol and unreacted raw material can be performed, for example, by distillation by concentration.

  In the present invention, it is omitted to extract and remove by-products from the reaction solution after the β-ketocarboxylate (II) is formed and before the acidified aqueous solution and silver nitrate are mixed. Is possible. Here, “extracting and removing a by-product from the reaction liquid” means, for example, removing a liquid containing a by-product from the reaction liquid without adding a washing solvent separately, After the solvent is added and separated into two layers, the by-product generated by the reaction is intentionally removed from the reaction solution (aqueous solution) together with the solvent component, such as removing the layer containing the by-product. Point to. That is, in the present invention, it is possible to perform no purification operation by extracting and removing by-products between the time when the β-ketocarboxylate (II) is formed and the time when silver nitrate is mixed. Since β-ketocarboxylic acid ester (III) does not correspond to a “by-product” as described above, β-ketocarboxylate (II) is produced and then acidified aqueous solution and silver nitrate are used. It may or may not be extracted and removed before mixing. From the viewpoint of further simplifying the process, it is preferable not to extract and remove the β-ketocarboxylic acid ester (III).

  In the present invention, after completion of the “β-ketocarboxylate (II) production step”, the reaction solution contains a β-ketocarboxylate (II) as necessary, except that it is contained in an aqueous solution. On the other hand, it is preferable to continue the “acidification step” without performing other operations. That is, it is preferable to perform each process continuously between these processes, without adding the various solvent and reagent which are arbitrary components.

  In the present invention, the silver (I) is particularly preferably silver isobutyryl acetate, silver benzoyl acetate, silver propionyl acetate, silver pivaloyl acetate, silver acetoacetate, silver 2-methylacetoacetate (α-methylacetoacetate silver) and 2- Suitable for production of silver ethyl acetoacetate (α-ethyl acetoacetate silver). In addition, the present invention provides an intermediate β-ketocarboxylic acid having a relatively high hydrophilicity, for example, a β-ketocarboxylic acid silver (I) having no highly lipophilic group such as a benzene ring. And is more suitable for the production of silver isobutyryl acetate, silver propionyl acetate, silver pivaloyl acetate, silver acetoacetate, silver 2-methylacetoacetate and silver 2-ethylacetoacetate.

According to the present invention, as described above, high-quality silver β-ketocarboxylate (I) equal to or higher than the conventional product can be obtained in a simpler process than the conventional production method, that is, in a smaller number of processes and in a shorter time. . For example, unlike the conventional manufacturing method, it is possible to omit the extraction and removal of by-products in the middle of the process, so that the problem that the separation of the aqueous layer and the organic layer does not proceed cleanly during extraction washing can be solved, Manufacturing time can be greatly reduced. Furthermore, since impurities can be sufficiently separated from the target product, the purity of silver β-ketocarboxylate can be improved, and impurities that delay the drying of silver β-ketocarboxylate can be greatly reduced, greatly increasing the drying time. The production time of the silver β-ketocarboxylate can be further shortened.
The production method of the present invention having the above advantages is particularly suitable for production on a large scale, and is particularly excellent in that it can suppress a decrease in production suitability associated with scale-up, which is often a problem in industrialization.

  Moreover, according to this invention, the yield of silver (ketocarboxylate) (I) improves rather than before by using a seed crystal. This is particularly advantageous in that silver β-ketocarboxylate can be obtained at low cost by large-scale production.

  The β-ketocarboxylate silver (I) obtained by the production method of the present invention decomposes at a low temperature of 210 ° C. or less, for example, without using a reducing agent, and thus is useful as a metal silver forming material. And the use of this metallic silver is not specifically limited. The β-ketocarboxylate silver (I) can be easily prepared by, for example, blending an organic base, alcohol, and other components as necessary to form a silver ink composition, which is applied to a substrate and heated. Metal silver can be formed.

  Hereinafter, the present invention will be described in more detail with reference to specific examples. However, the present invention is not limited to the following examples. In addition, the yield of β-ketocarboxylate (I) shown in the following examples is based on β-ketocarboxylate (III) unless otherwise specified.

<Production of silver 2-methylacetoacetate>
[Example 1]
10.0 mass% sodium hydroxide (NaOH) aqueous solution (5374.1 g, sodium hydroxide 13.4 mol) was added to 2-methylacetoacetic acid ethyl (manufactured by Wako Pure Chemical Industries, 1407.2 g (9 0.8 mol)) was added dropwise over 30 minutes, followed by further stirring at 20 ° C. for 4 hours for hydrolysis to produce sodium 2-methylacetoacetate.
Next, while cooling the obtained reaction solution containing sodium 2-methylacetoacetate to 5 to 10 ° C., 4.3% by mass nitric acid (HNO ₃ ) aqueous solution (2019.0 g, nitric acid 1.4 mol) was added thereto for 30 minutes. The solution was added dropwise and stirred for another 30 minutes. At this time, the pH of the obtained aqueous solution was 5.8 as shown in Table 1.
Further, while stirring the obtained aqueous solution, nitrogen gas was allowed to flow into the aqueous solution at a flow rate of 3 L / min for 30 minutes at 5 ° C., and then the aqueous solution was filtered with an Advantech nonwoven fabric. And ethanol (500.0g) was added to the aqueous solution after filtration, and it stirred at 5 degreeC for 30 minutes.
Separately, a 50.0% by mass silver nitrate (AgNO ₃ ) aqueous solution (3047.5 g, silver nitrate 9.0 mol) was prepared, and seed crystals of silver 2-methylacetoacetate (80.0 g) were added thereto, and 2 minutes later. The aqueous solution having the pH of 5.8 was added dropwise to the aqueous silver nitrate solution over 10 minutes so that the temperature was 8 ° C. From the start of dropping to the start of precipitation of the target crystals, the seed crystals were not fully dissolved, and some of them remained precipitated. Furthermore, silver 2-methylacetoacetate was produced by stirring at 5 ° C. for 30 minutes. Table 1 shows the ratio of each raw material used.
Then, the obtained reaction solution was filtered to separate crystals, and the crystals were washed once with water (2.5 L), then further washed with ethanol (3 L) three times, and then dried. Crystals of silver 2-methylacetoacetate as the target product were obtained (yield 51%).
The time required from the hydrolysis of ethyl 2-methylacetoacetate to the completion of drying of the crystals of silver 2-methylacetoacetate was about 8 hours. For example, filtration and washing of silver 2-methylacetoacetate took about 1 hour, and drying of crystals of silver 2-methylacetoacetate took about 4 hours.

[Example 2]
12.0 mass% sodium hydroxide aqueous solution (4478.4 g, sodium hydroxide 13.4 mol) was adjusted to 35 ° C. or lower with ethyl 2-methylacetoacetate (manufactured by Wako Pure Chemical Industries, 1407.2 g (9.8 mol)). ) Was added dropwise over 30 minutes, followed by further stirring at 20 ° C. for 4 hours for hydrolysis to produce sodium 2-methylacetoacetate.
Next, while cooling the obtained reaction solution containing sodium 2-methylacetoacetate to 5 to 10 ° C., a 19.8 mass% nitric acid aqueous solution (487.0 g, nitric acid 1.5 mol) was added dropwise over 30 minutes. Then water (100 g) was added and stirred for another 30 minutes. At this time, the pH of the obtained aqueous solution was 5.8 as shown in Table 1.
Further, while stirring the obtained aqueous solution, nitrogen gas was allowed to flow into the aqueous solution at a flow rate of 3 L / min for 30 minutes at 5 ° C., and then the aqueous solution was filtered with an Advantech nonwoven fabric. And ethanol (500.0g) was added to the aqueous solution after filtration, and it stirred at 5 degreeC for 30 minutes.
Separately, a 50.0% by mass silver nitrate aqueous solution (3047.5 g, silver nitrate 9.0 mol) was prepared, and seed crystals of silver 2-methylacetoacetate (80.0 g) were added thereto. The total amount of the aqueous solution having the pH of 5.8 was dropped into the aqueous silver nitrate solution over 10 minutes. From the start of dropping to the start of precipitation of the target crystals, the seed crystals were not fully dissolved, and some of them remained precipitated. Furthermore, silver 2-methylacetoacetate was produced by stirring at 5 ° C. for 30 minutes. Table 1 shows the ratio of each raw material used.
Then, the obtained reaction solution was filtered to separate crystals, and the crystals were washed once with water (2.5 L), then further washed with ethanol (3 L) three times, and then dried. Crystals of silver 2-methylacetoacetate as the target product were obtained (yield 59%).
The time required from the hydrolysis of ethyl 2-methylacetoacetate to the completion of drying of the crystals of silver 2-methylacetoacetate was the same as in Example 1.

  The obtained silver 2-methylacetoacetate was analyzed by Fourier transform infrared spectroscopy (FT-IR) according to the following method. The results are shown in FIG. Note that. FIG. 1 also shows the analysis result of silver 2-methylacetoacetate obtained in Reference Example 1 described later.

・ FT-IR
Using the following FT-IR apparatus, an FT-IR spectrum was measured according to a conventional method.
(Analysis equipment)
FT-IR apparatus: Spectrum One / Auto Image FT-IR Spectrometer (Perkin Elmer)
Auxiliary equipment: Universal ATR Sampling Accessory
(Analysis conditions)
Measurement range: 4000 to 600 cm ⁻¹
Number of measurements: 4 times Temperature: room temperature Atmosphere: air

[Example 3]
As shown in Table 1, instead of the 12.0% by mass sodium hydroxide aqueous solution (4478.4 g, sodium hydroxide 13.4 mol), the 14.5% by mass sodium hydroxide aqueous solution (3706.3 g, sodium hydroxide 13 .4 mol) was replaced with 19.8% by mass nitric acid aqueous solution (487.0 g, nitric acid 1.5 mol), except that 25.0% by mass nitric acid aqueous solution (384.7 g, nitric acid 1.5 mol) was used. Obtained silver 2-methylacetoacetate crystals in the same manner as in Example 2 (yield 61%).
The time required from the hydrolysis of ethyl 2-methylacetoacetate to the completion of drying of the crystals of silver 2-methylacetoacetate was the same as in Example 1.
The obtained silver 2-methylacetoacetate was analyzed by FT-IR as in Example 2. The results are shown in FIG.

[Example 4]
As shown in Table 1, instead of the 12.0 mass% sodium hydroxide aqueous solution (4478.4 g, sodium hydroxide 13.4 mol), the 16.0 mass% sodium hydroxide aqueous solution (3358.8 g, sodium hydroxide 13 .4 mol) was replaced with 19.8% by mass nitric acid aqueous solution (487.0 g, nitric acid 1.5 mol), except that 25.0% by mass nitric acid aqueous solution (384.7 g, nitric acid 1.5 mol) was used. Gave crystals of silver 2-methylacetoacetate as in Example 2 (yield 66%).
The time required from the hydrolysis of ethyl 2-methylacetoacetate to the completion of drying of the crystals of silver 2-methylacetoacetate was the same as in Example 1.
The obtained silver 2-methylacetoacetate was analyzed by FT-IR as in Example 2. The results are shown in FIG.

[Example 5]
As shown in Table 1, instead of the 12.0 mass% aqueous sodium hydroxide solution (4478.4 g, sodium hydroxide 13.4 mol), the 20.0 mass% sodium hydroxide aqueous solution (2687.1 g, sodium hydroxide 13 4mol) in place of 19.8% by mass nitric acid aqueous solution (487.0g, nitric acid 1.5mol), and 25.0% by mass nitric acid aqueous solution (384.7g, nitric acid 1.5mol), respectively, A silver 2-methylacetoacetate crystal was obtained in the same manner as in Example 2 except that the amount of water used after dropping the nitric acid aqueous solution was changed to 50 g instead of 100 g (yield 69%).
The time required from the hydrolysis of ethyl 2-methylacetoacetate to the completion of drying of the crystals of silver 2-methylacetoacetate was the same as in Example 1.
The obtained silver 2-methylacetoacetate was analyzed by FT-IR as in Example 2. The results are shown in FIG.

[Comparative Example 1]
According to the method described in Japanese Patent Application No. 2007-523425, silver 2-methylacetoacetate was produced by a conventional method.
That is, sodium hydroxide (1.92 g) was dissolved in water (8 mL), and while stirring this at room temperature, ethyl 2-methylacetoacetate (Wako Pure Chemical Industries, Ltd., 5.77 g) was added dropwise for another 30 minutes. Stir. Thereafter, ethanol was removed by concentration using a rotary evaporator, and the remaining aqueous layer was washed with ether. Ether (20 mL) was added thereto, and a solution obtained by dissolving 2.35 g of concentrated sulfuric acid in 8 mL of water was added dropwise with stirring under ice cooling. The ether layer was separated, and the aqueous layer was salted out and extracted with ether. The ether layer was collected to obtain an ether solution of 2-methylacetoacetic acid.

Diethanolamine (4.4 g) was dissolved in water (5 mL), and this solution was added to an ether solution of 2-methylacetoacetic acid under ice cooling. Subsequently, a solution of silver nitrate (6.8 g) dissolved in water (8 mL) was added dropwise. Then, the precipitated white precipitate was filtered, washed with ice water, followed by isopropanol, and dried to obtain silver 2-methylacetoacetate as a white precipitate (yield 48%).
The time required from hydrolysis of ethyl 2-methylacetoacetate, that is, from concentration by a rotary evaporator to completion of drying of silver 2-methylacetoacetate crystals was about 11.5 hours. In particular, filtration and washing of silver 2-methylacetoacetate did not proceed rapidly, and took about 2 hours. Further, the drying of the silver 2-methylacetoacetate crystals did not proceed rapidly, and took about 6 hours.
Thus, in this comparative example, not only was the number of steps large, but the filterability and drying properties of silver 2-methylacetoacetate were not good, and the production time was significantly longer than in Example 1.

  The obtained silver 2-methylacetoacetate was subjected to (1) inductively coupled plasma-mass spectrometry (ICP-MS), (2) elemental analysis, (3) trace total nitrogen analysis, and (4) analysis by FT-IR. did. Each analysis method is as follows.

(1) ICP-MS
Na content was calculated | required in accordance with the conventional method with the following analyzer and analysis conditions.
(Analysis equipment)
Decomposing equipment: CEM, MARS5
Analyzer (ICP-MS): 7500cs (manufactured by Agilent Technologies)
(Analysis conditions)
RF output: 1.5 kW
Nebulizer: Polytetrafluoroethylene coaxial nebulizer m / z: 23
Reaction gas mode: ON (H ₂ )
(2) Elemental analysis The nitrogen (N) content was calculated | required in accordance with the conventional method using the following CHN elemental analyzer.
(Analysis equipment)
CHN elemental analyzer: vario ELIII (manufactured by Elementar)
(Analysis conditions)
Combustion tube temperature: 950 ° C
Reduction tube temperature: 500 ° C
Carrier gas: He 200 mL / min Detector: TCD
Standard sample: Acetanilide (standard reagent for elemental analysis) N: 10.36%
Quantitative method: Multi-inspection curve method using standard sample (3) Trace total nitrogen analysis Using the following trace total nitrogen analyzer, the total nitrogen amount was determined according to a conventional method.
(Analysis equipment)
Trace total nitrogen analyzer: TN-110 (Mitsubishi Chemical Corporation)
(Analysis conditions)
Temperature: 800 ° C (pyrolysis furnace), 900 ° C (oxidation furnace)
Carrier gas: oxygen (300 mL / min), argon / oxygen (400 mL / min)
Standard sample: pyridine / toluene solution Detector: Low-pressure chemiluminescence detector Range: High
(4) FT-IR
Analysis was performed in the same manner as in Example 2.

The analysis results are as follows.
(1) Na content: 4.4 μg / g
(2) Elemental analysis values: C = 26.74%, H = 3.137%, N = 0.006% (theoretical values: C = 26.93%, H = 3.16%, N = 0.00 %)
(3) N content: 910 μg / g
(4) FT-IR spectrum: as shown in FIG.

[Reference Example 1]
Under water cooling, sodium hydroxide (NaOH) (36.7 g (917.5 mmol)) was dissolved in water (314.4 g), and the temperature of the resulting aqueous sodium hydroxide solution was adjusted to room temperature. The whole amount was added dropwise over 30 minutes to ethyl 2-methylacetoacetate (manufactured by Wako Pure Chemicals, 88 g (610.3 mmol)), followed by further overnight stirring at 20 ° C. for hydrolysis.
Subsequently, ethanol and unreacted raw materials were removed by concentration using a rotary evaporator, and the resulting residue containing sodium 2-methylacetoacetate was cooled to 5 to 10 ° C., and 69.0% nitric acid (HNO ₃ ) was added thereto. An aqueous solution (36.7 g) was added dropwise over 10 minutes, and the mixture was further stirred for about 10 minutes. At this time, the pH of the obtained reaction solution was 4.6 as shown in Table 1.
Next, silver nitrate (AgNO ₃ ) (76.2 g (448.5 mmol)) was dissolved in water (76.2 g) to prepare an aqueous silver nitrate solution having a pH of 6.5. The total amount of the above-mentioned reaction solution of pH 4.6 was dropped over 30 minutes and stirred for about 10 minutes to produce silver 2-methylacetoacetate. Table 1 shows the ratio of each raw material used.
Next, the obtained reaction solution was filtered to separate crystals, and the crystals were washed twice with water (20 mL) and then washed with an appropriate amount of 2-propanol. Further, the obtained crystals were stirred and washed in 2-propanol (500 mL), filtered, washed with an appropriate amount of 2-propanol, and then dried to obtain crystals of silver 2-methylacetoacetate as a target product. (Yield 39%) was obtained.
The time required from hydrolysis of ethyl 2-methylacetoacetate, that is, from concentration by rotary evaporator to completion of drying of silver 2-methylacetoacetate crystals was about 5 hours. For example, filtration and washing of silver 2-methylacetoacetate took about 1.5 hours, and drying of silver 2-methylacetoacetate crystals took about 2 hours.

As in Comparative Example 1, the obtained silver 2-methylacetoacetate was subjected to (1) ICP-MS, (2) elemental analysis, (3) trace total nitrogen analysis, and (4) analysis by FT-IR. did. The analysis results are as follows.
(1) Na content: 16 μg / g
(2) Elemental analysis values: C = 26.86%, H = 3.184%, N = 0.00% (theoretical values: C = 26.93%, H = 3.16%, N = 0.00 %)
(3) N content: 32 μg / g
(4) FT-IR spectrum: as shown in FIG.

  From the analysis result of Reference Example 1, it can be confirmed that the target product was obtained. Furthermore, those obtained in Examples 1 to 5 have the same properties as those of Reference Example 1, and Examples 2 to 5 Since the analysis result of FT-IR was the same as the analysis result of Reference Example 1, it was confirmed that the target product was also obtained in Examples 1-5.

  As is clear from the above results, in Examples 1 to 5 and Reference Example 1, high-quality silver β-ketocarboxylate (I) was obtained in a high yield by a simpler process than Comparative Example 1. In particular, in Examples 1 to 5, β-ketocarboxylate silver (I) can be obtained in a higher yield than Reference Example 1, and by increasing the concentration of aqueous sodium hydroxide or nitric acid, β-ketocarboxylate silver The yield of (I) was further improved.

<Production of silver 2-methylacetoacetate>
[Example 6]
An aqueous solution of 10.0% by mass sodium hydroxide (NaOH) (5480 g, 13.7 mol of sodium hydroxide) was adjusted to 35 ° C. or lower with ethyl 2-methylacetoacetate (1800 g (12.5 mol), manufactured by Wako Pure Chemical Industries, Ltd.) The whole amount was added dropwise over 30 minutes, followed by further stirring at 20 ° C. for 4 hours to carry out hydrolysis to produce sodium 2-methylacetoacetate.
Next, while cooling the obtained reaction solution containing sodium 2-methylacetoacetate to 5 to 10 ° C., a 25% by mass nitric acid (HNO ₃ ) aqueous solution (385 g, nitric acid 1.5 mol) was added dropwise over 30 minutes. The mixture was further stirred for 30 minutes. At this time, the pH of the obtained aqueous solution was 5.8 as shown in Table 2.
Further, while stirring the obtained aqueous solution, nitrogen gas was allowed to flow into the aqueous solution at a flow rate of 3 L / min for 30 minutes at 5 ° C., and then the aqueous solution was filtered with an Advantech nonwoven fabric. And ethanol (500 mL) was added to the aqueous solution after filtration, and it stirred at 5 degreeC for 30 minutes.
Separately, a 50.0% by mass silver nitrate (AgNO ₃ ) aqueous solution (3048 g, silver nitrate 9.0 mol) was prepared, and silver 2-methylacetoacetate seed crystals (80 g) were added thereto. The total amount of the aqueous solution having the pH of 5.8 was dropped into the aqueous silver nitrate solution over 10 minutes. From the start of dropping to the start of precipitation of the target crystals, the seed crystals were not fully dissolved, and some of them remained precipitated. Furthermore, silver 2-methylacetoacetate was produced by stirring at 5 ° C. for 30 minutes. Table 2 shows the ratio of each raw material used.
Next, the reaction solution obtained was filtered to separate the crystals, and the crystals were washed once with water (2.5 L), then further washed with ethanol (3 L) three times, and then vacuum-dried. As a result, crystals of silver 2-methylacetoacetate as a target product were obtained (42% yield).
The time required from the hydrolysis of ethyl 2-methylacetoacetate to the completion of drying of the crystals of silver 2-methylacetoacetate was about 8 hours. For example, filtration and washing of silver 2-methylacetoacetate took about 1 hour, and drying of crystals of silver 2-methylacetoacetate took about 4 hours.

[Example 7]
In the same manner as in Example 6, except that the amount of 50.0 mass% silver nitrate aqueous solution used was 3901 g (silver nitrate 11.5 mol) instead of 3048 g (silver nitrate 9.0 mol), crystals of silver 2-methylacetoacetate were prepared. Obtained (yield 45%).
The time required from the hydrolysis of ethyl 2-methylacetoacetate to the end of the drying of silver 2-methylacetoacetate crystals was the same as in Example 6.

[Example 8]
In the same manner as in Example 6, except that the amount of 50.0% by mass silver nitrate aqueous solution used was changed to 4353 g (silver nitrate 12.8 mol) instead of 3048 g (silver nitrate 9.0 mol), crystals of silver 2-methylacetoacetate were obtained. Obtained (yield 51%).
The time required from the hydrolysis of ethyl 2-methylacetoacetate to the end of the drying of silver 2-methylacetoacetate crystals was the same as in Example 6.

[Example 9]
In the same manner as in Example 6, except that the amount of 50.0% by mass silver nitrate aqueous solution used was changed to 5000 g (silver nitrate 14.7 mol) instead of 3048 g (silver nitrate 9.0 mol), crystals of silver 2-methylacetoacetate were obtained. Obtained (yield 49%).
The time required from the hydrolysis of ethyl 2-methylacetoacetate to the end of the drying of silver 2-methylacetoacetate crystals was the same as in Example 6.

[Example 10]
The crystals of silver 2-methylacetoacetate were prepared in the same manner as in Example 6 except that the amount of 50.0% by mass silver nitrate aqueous solution was changed to 6530 g (silver nitrate 19.2 mol) instead of 3048 g (silver nitrate 9.0 mol). Obtained (yield 47%).
The time required from the hydrolysis of ethyl 2-methylacetoacetate to the end of the drying of silver 2-methylacetoacetate crystals was the same as in Example 6.

In Examples 6 to 10, the amount of silver nitrate used was changed, but the yield (yield) of silver 2-methylacetoacetate was highest in Example 8, and the amount of silver nitrate used was Example 8. The yield of silver 2-methylacetoacetate decreased with distance from the amount used.
In addition, when the yield of silver 2-methylacetoacetate based on silver nitrate was calculated separately from the above yield of silver 2-methylacetoacetate based on ethyl 2-methylacetoacetate, Example 6: 58% Example 7: 48%, Example 8: 51%, Example 9: 42%, Example 10: 30%, and a tendency that the yield decreases as the amount of silver nitrate used increases. It was.

<Production of silver 2-methylacetoacetate>
[Example 11]
An aqueous solution of 10.0% by mass sodium hydroxide (NaOH) (5480 g, 13.7 mol of sodium hydroxide) was adjusted to 35 ° C. or lower with ethyl 2-methylacetoacetate (1800 g (12.5 mol), manufactured by Wako Pure Chemical Industries, Ltd.) The whole amount was added dropwise over 30 minutes, followed by further stirring at 20 ° C. for 4 hours to carry out hydrolysis to produce sodium 2-methylacetoacetate.
Next, while cooling the obtained reaction solution containing sodium 2-methylacetoacetate to 5 to 10 ° C., a 25% by mass nitric acid (HNO ₃ ) aqueous solution (385 g, nitric acid 1.5 mol) was added dropwise over 30 minutes. The mixture was further stirred for 30 minutes. At this time, the pH of the obtained aqueous solution was 5.8 as shown in Table 3.
Further, while stirring the obtained aqueous solution, nitrogen gas was allowed to flow into the aqueous solution at a flow rate of 3 L / min for 30 minutes at 5 ° C., and then the aqueous solution was filtered with an Advantech nonwoven fabric. And ethanol (500 mL) was added to the aqueous solution after filtration, and it stirred at 5 degreeC for 30 minutes.
Separately, a 50.0% by mass silver nitrate (AgNO ₃ ) aqueous solution (3048 g, silver nitrate 9.0 mol) was prepared, and silver 2-methylacetoacetate seed crystals (80 g) were added thereto. The total amount of the aqueous solution having the pH of 5.8 was dropped into the aqueous silver nitrate solution over 10 minutes. From the start of dropping to the start of precipitation of the target crystals, the seed crystals were not fully dissolved, and some of them remained precipitated. Furthermore, silver 2-methylacetoacetate was produced by stirring at 5 ° C. for 30 minutes.
Next, ethanol (0.5 L) was added to the reaction solution, and the mixture was stirred at 5 ° C. for 15 minutes. Table 4 shows the ratio (mass ratio) of the amount of alcohol occupying the total amount of the solvent (alcohol and water) in the reaction solution and the amount of ethanol (alcohol) added at this time. In addition, Table 3 shows the ratio of each raw material used.
Next, the obtained reaction solution was filtered to separate crystals, and the crystals were washed once with water (2.5 L), twice with ethanol (3 L), once with acetone (3 L), and in this order. Then, by vacuum drying, crystals of silver 2-methylacetoacetate as the target product were obtained (yield 43%).
The time required from the hydrolysis of ethyl 2-methylacetoacetate to the end of the drying of silver 2-methylacetoacetate crystals was the same as in Example 6.

[Example 12]
A silver 2-methylacetoacetate crystal was obtained in the same manner as in Example 11 except that the amount of ethanol added to the reaction solution after producing silver 2-methylacetoacetate was changed to 4 L instead of 0.5 L. (Yield 46%).
The time required from the hydrolysis of ethyl 2-methylacetoacetate to the end of the drying of silver 2-methylacetoacetate crystals was the same as in Example 6.

[Example 13]
Crystals of silver 2-methylacetoacetate were obtained in the same manner as in Example 11 except that the amount of ethanol added to the reaction solution after producing silver 2-methylacetoacetate was changed to 8 L instead of 0.5 L. (Yield 48%).
The time required from the hydrolysis of ethyl 2-methylacetoacetate to the end of the drying of silver 2-methylacetoacetate crystals was the same as in Example 6.

[Example 14]
A silver 2-methylacetoacetate crystal was obtained in the same manner as in Example 11 except that the amount of ethanol added to the reaction solution after producing silver 2-methylacetoacetate was changed to 12 L instead of 0.5 L. (Yield 48%).
The time required from the hydrolysis of ethyl 2-methylacetoacetate to the end of the drying of silver 2-methylacetoacetate crystals was the same as in Example 6.

[Example 15]
After producing silver 2-methylacetoacetate, instead of adding ethanol (0.5 L) to the reaction solution, 2-methylacetoacetic acid was added in the same manner as in Example 11 except that methanol (8 L) was added. Silver crystals were obtained (yield 50%).
The time required from the hydrolysis of ethyl 2-methylacetoacetate to the end of the drying of silver 2-methylacetoacetate crystals was the same as in Example 6.

[Example 16]
After producing silver 2-methylacetoacetate, instead of adding ethanol (0.5 L) to the reaction solution, 2-propanol (8 L) was added as in Example 11 except that 2-propanol (8 L) was added. Crystals of methyl methylacetoacetate were obtained (43% yield).
The time required from the hydrolysis of ethyl 2-methylacetoacetate to the end of the drying of silver 2-methylacetoacetate crystals was the same as in Example 6.

In Examples 11 to 16, the type or amount of alcohol added as a poor solvent was changed before taking out silver 2-methylacetoacetate, but when the addition amount was the same, methanol, ethanol, The yield (yield) of silver 2-methylacetoacetate was higher in the order of -propanol. And when alcohol was fixed to ethanol, the yield of silver 2-methylacetoacetate increased as the amount added increased.
In addition, when the yield of silver 2-methylacetoacetate based on silver nitrate was calculated separately from the above yield of silver 2-methylacetoacetate based on ethyl 2-methylacetoacetate, Example 11: 60% Example 12: 64%, Example 13: 66%, Example 14: 67%, Example 15: 70%, Example 16: 60%, and when the addition amount is the same as above The yield (yield) of silver 2-methylacetoacetate is higher in the order of methanol, ethanol and 2-propanol. When the alcohol is fixed to ethanol, the yield of silver 2-methylacetoacetate increases as the amount added increases. Became high.

<Production of silver 2-methylacetoacetate>
[Example 17]
11.0 mass% sodium hydroxide (NaOH) aqueous solution (4981 g, sodium hydroxide 13.7 mol), ethyl 2-methylacetoacetate (manufactured by Wako Pure Chemical Industries, 1800 g (12.5 mol)) The whole amount was added dropwise over 30 minutes, followed by further stirring at 20 ° C. for 4 hours to carry out hydrolysis to produce sodium 2-methylacetoacetate.
Next, while cooling the obtained reaction solution containing sodium 2-methylacetoacetate to 5 to 10 ° C., a 25% by mass nitric acid (HNO ₃ ) aqueous solution (385 g, nitric acid 1.5 mol) was added dropwise over 30 minutes. The mixture was further stirred for 30 minutes. At this time, the pH of the obtained aqueous solution was 5.8 as shown in Table 5.
Further, while stirring the obtained aqueous solution, nitrogen gas was allowed to flow into the aqueous solution at a flow rate of 3 L / min for 30 minutes at 5 ° C., and then the aqueous solution was filtered with an Advantech nonwoven fabric. And ethanol (500 mL) was added to the aqueous solution after filtration, and it stirred at 5 degreeC for 30 minutes.
Separately, a 50.0% by mass silver nitrate (AgNO ₃ ) aqueous solution (3048 g, silver nitrate 9.0 mol) was prepared, and silver 2-methylacetoacetate seed crystals (80 g) were added thereto. The total amount of the aqueous solution having the pH of 5.8 was dropped into the aqueous silver nitrate solution over 10 minutes. From the start of dropping to the start of precipitation of the target crystals, the seed crystals were not fully dissolved, and some of them remained precipitated. Furthermore, silver 2-methylacetoacetate was produced by stirring at 5 ° C. for 30 minutes.
Subsequently, the obtained reaction solution is filtered to separate crystals, and the crystals are washed once with water (2.5 L), three times with ethanol (3 L) in this order, and then vacuum-dried. As a result, crystals of silver 2-methylacetoacetate as a target product were obtained (yield 51%).
The time required from the hydrolysis of ethyl 2-methylacetoacetate to the completion of drying of the crystals of silver 2-methylacetoacetate was about 8 hours. For example, filtration and washing of silver 2-methylacetoacetate took about 1 hour, and drying of crystals of silver 2-methylacetoacetate took about 4 hours.

[Example 18]
After producing silver 2-methylacetoacetate, ethanol (8 L) was added to the reaction solution, and the fourth washing of the filtered 2-methylacetoacetate crystals was replaced with ethanol (3 L) and acetone (3 L). In the same manner as in Example 17 except that the procedure was performed in the same manner as in Example 17, crystals of silver 2-methylacetoacetate were obtained (yield 56%).
The time required from the hydrolysis of ethyl 2-methylacetoacetate to the completion of the drying of silver 2-methylacetoacetate crystals was 2 hours.

[Example 19]
After producing silver 2-methylacetoacetate, ethanol (4 L) was added to the reaction solution, and the first washing of the filtered 2-methylacetoacetate crystals was replaced with water (2.5 L), 2 in the same manner as in Example 17 except that the 4th washing was performed with acetone (3 L) instead of ethanol (3 L). -Crystals of silver methylacetoacetate were obtained (yield 60%).
The time required from the hydrolysis of ethyl 2-methylacetoacetate to the end of drying of the silver 2-methylacetoacetate crystals was the same as in Example 18.

[Example 20]
After producing silver 2-methylacetoacetate, methanol (4 L) was added to the reaction solution, and the first washing of the filtered 2-methylacetoacetate crystals was replaced with water (2.5 L), 2 in the same manner as in Example 17 except that it was carried out with a mixed solvent (3 L) / methanol (5/5, mass ratio) and the fourth washing was carried out with acetone (3 L) instead of ethanol (3 L). -Crystals of silver methylacetoacetate were obtained (yield 72%).
The time required from the hydrolysis of ethyl 2-methylacetoacetate to the end of drying of the silver 2-methylacetoacetate crystals was the same as in Example 18.

[Example 21]
After forming silver 2-methylacetoacetate, methanol (4 L) was added to the reaction solution, and the crystals of silver 2-methylacetoacetate separated by filtration were washed once with water (2.5 L) and ethanol (3 L). In this order, the water / methanol (5/5, mass ratio) mixed solvent (3 L) once, methanol (3 L) twice, acetone (3 L) once, A silver 2-methylacetoacetate crystal was obtained (yield 75%) in the same manner as in Example 17 except that the procedure was performed in order.
The time required from the hydrolysis of ethyl 2-methylacetoacetate to the end of drying of the silver 2-methylacetoacetate crystals was the same as in Example 18.

  Table 5 shows the ratio of each raw material used. Table 6 shows the types and amounts of the solvent added to the reaction solution after the formation of silver 2-methylacetoacetate, and the types and amounts of the washing solvent for the filtered 2-methylacetoacetate crystals. Show.

In Examples 17 to 21, before taking out silver 2-methylacetoacetate, at least one of the kind and addition amount of alcohol to be added as a poor solvent was changed, and the kind and addition of the washing solvent at the time of taking out 2-methylacetoacetate silver. At least one of the quantities is changed.
As is clear from the comparison between Example 17 and Examples 18 to 21, the yield (yield) of silver 2-methylacetoacetate was improved by the addition of alcohol.
Further, as is clear from the comparison between Example 18 and Example 19, the amount of alcohol as a poor solvent is reduced by using a water / ethanol mixed solvent instead of water as the first washing solvent. Even so, the yield (yield) of silver 2-methylacetoacetate was improved.
Further, as is clear from the comparison between Example 19 and Example 20, the type of alcohol that is a poor solvent and the type of alcohol that is used as the first washing solvent are methanol instead of ethanol. The yield (yield) of silver 2-methylacetoacetate was improved.
Further, as is clear from the comparison between Example 20 and Example 21, 2-methyl acetoacetate silver was obtained by changing the alcohol used as the second and third washing solvent to methanol instead of ethanol. The yield (yield) of was improved.

  For the silver 2-methylacetoacetate obtained in Examples 17 to 21, FT-IR was measured by the same method as in Example 2, and further, decomposition initiation temperature and weight were determined by simultaneous differential thermal-thermogravimetric measurement (TG-DTA). As a result of measuring the decrease, the same results as those of silver 2-methylacetoacetate in other examples such as Example 2 were obtained, and it was confirmed that the quality was good even if the yield was improved.

  The present invention can be used for the production of metallic silver as a recording material, a printing plate material, and a highly conductive material.

Claims (6)

Producing a β-ketocarboxylate represented by the following general formula (II):
Mixing an aqueous solution containing the produced β-ketocarboxylate and nitric acid to make the aqueous solution acidic;
Mixing the acidified aqueous solution and silver nitrate to produce silver β-ketocarboxylate represented by the following general formula (I);
Removing the produced silver β-ketocarboxylate;
A process for producing silver β-ketocarboxylate having
After the step of acidifying the aqueous solution and before the step of taking out the silver β-ketocarboxylate, the step of introducing seed crystals of the silver β-ketocarboxylate,
The step of introducing the seed crystal is performed from the stage from the start of mixing of the acidified aqueous solution and silver nitrate to 10 minutes before the start of mixing of the acidified aqueous solution and silver nitrate until 10 minutes after the start of mixing. A method for producing silver β-ketocarboxylate, which is carried out between steps.

(In the formula, R ^a is ^a linear or branched alkyl group having 1 to 20 carbon atoms or ^a phenyl group; X ^a is a hydrogen atom or linear or branched chain having 1 to 20 carbon atoms; And the two X ^{a s} may be the same or different from each other; M ⁺ is a sodium ion, a potassium ion or a lithium ion.)   2. The method for producing a silver β-ketocarboxylate according to claim 1, wherein when the acidified aqueous solution or the silver nitrate is used as an aqueous solution, the seed crystal is introduced into the silver nitrate aqueous solution.   The method for producing a β-ketocarboxylate according to claim 1 or 2, further comprising a step of allowing an inert gas to flow into the acidified aqueous solution before mixing with the silver nitrate.   The method for producing a silver β-ketocarboxylate according to any one of claims 1 to 3, further comprising a step of filtering the acidified aqueous solution before mixing with the silver nitrate. The step of producing the β-ketocarboxylate salt has a step of hydrolyzing a β-ketocarboxylate ester represented by the following general formula (III) using sodium hydroxide, potassium hydroxide or lithium hydroxide. The method for producing silver β-ketocarboxylate according to any one of claims 1 to 4, wherein:

Wherein R ^a is ^a linear or branched alkyl group having 1 to 20 carbon atoms or a phenyl group; R ^b is a linear or branched alkyl group having 1 to 5 carbon atoms or X ^a is a hydrogen atom or ^a linear or branched alkyl group having 1 to 20 carbon atoms, and the two X ^a may be the same or different from each other. R ^a is ^a linear or branched alkyl group or phenyl group having 1 to 5 carbon atoms, and the X ^a is a hydrogen atom or ^a linear or branched alkyl group having 1 to 3 carbon atoms. It is group, The manufacturing method of the beta-ketocarboxylate silver as described in any one of Claims 1-5 characterized by the above-mentioned.

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