JP2005082501A - Method for manufacturing purified benzyl ester compound - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for mass-productively manufacturing a benzyl ester compound in an industrial scale which permits the manufacture of a purified cyclopropanecarboxylic acid benzyl ester compound of high purity in an excellent yield with reduced energy consumption. <P>SOLUTION: The method for manufacturing the purified ester compound comprises steam-distilling, using a distillation apparatus equipped with a rectification column, a crude product containing the cyclopropanecarboxylic acid benzyl ester compound obtained by a transesterification reaction of a cyclopropanecarboxylic acid ester compound with a benzyl alcohol compound. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a method for producing a purified cyclopropanecarboxylic acid benzyl ester compound.

（式中、Ｒ^１はメチル基または炭素数３〜４のアルケニル基を表し、Ｒ^２は水素原子またはメチル基を表し、Ｒ^４は、ハロゲン原子で置換されていてもよい炭素数１〜３のアルキル基、ハロゲン原子で置換されていてもよい炭素数２〜３のアルケニル基、ハロゲン原子で置換されていてもよい炭素数１〜３のアルコキシル基、ハロゲン原子で置換されていてもよい炭素数１〜３のアルキルチオ基、ハロゲン原子で置換されていてもよい炭素数１〜３のアルコキシル基が結合したメチル基、水素原子またはハロゲン原子を表す。）
で示されるシクロプロパンカルボン酸 ２，３，５，６−テトラフルオロベンジルエステル化合物が有害生物防除剤の有効成分として有用であることが知られており（例えば、特許文献１）、その製造方法としては、特許文献２において、エステル交換反応を実施して得られたベンジルエステル化合物の粗生成物に、水を加えて共沸蒸留することにより、純度９７．２％の精ベンジルエステル化合物を１０７ｇ、収率９３．２％で得られたことが開示されている。 Formula (IV)

(In the formula, R ¹ represents a methyl group or an alkenyl group having 3 to 4 carbon atoms, R ² represents a hydrogen atom or a methyl group, and R ⁴ has 1 to 3 carbon atoms which may be substituted with a halogen atom. An alkyl group, an alkenyl group having 2 to 3 carbon atoms which may be substituted with a halogen atom, an alkoxyl group having 1 to 3 carbon atoms which may be substituted with a halogen atom, or a carbon which may be substituted with a halogen atom Represents a methyl group, a hydrogen atom or a halogen atom to which an alkylthio group having 1 to 3 carbon atoms and an alkoxyl group having 1 to 3 carbon atoms which may be substituted with a halogen atom are bonded.
It is known that a cyclopropanecarboxylic acid 2,3,5,6-tetrafluorobenzyl ester compound represented by the formula (1) is useful as an active ingredient of a pest control agent (for example, Patent Document 1), In Patent Document 2, 107 g of a purified benzyl ester compound having a purity of 97.2% was obtained by adding water to the crude product of the benzyl ester compound obtained by carrying out the transesterification reaction and performing azeotropic distillation. It is disclosed that the yield was 93.2%.

JP 2000-63329 A JP 2002-167355 A ([0022] to [0023] Production Example 1)

However, when the present inventors examined a method for producing a large amount of a pure benzyl ester compound on an industrial scale in accordance with the above production method, the yield may be reduced, and water used in azeotropic distillation may be reduced. It became clear that the problem was that the amount of energy required for distilling water was large due to the large amount.
It is an object of the present invention to provide a purified cyclopropanecarboxylic acid benzyl ester compound (IV) having high purity, excellent yield, and reduced energy consumption even when a large amount of benzyl ester compound is produced on an industrial scale. ) Is provided.

（式中、Ｒ^１はメチル基または炭素数３〜４のアルケニル基を表し、Ｒ^２は水素原子またはメチル基を表し、Ｒ^３はメチル基またはエチル基を表す。）
で示されるエステル化合物と、式（II）

（式中、Ｒ^４は、ハロゲン原子で置換されていてもよい炭素数１〜３のアルキル基、ハロゲン原子で置換されていてもよい炭素数２〜３のアルケニル基、ハロゲン原子で置換されていてもよい炭素数１〜３のアルコキシル基、ハロゲン原子で置換されていてもよい炭素数１〜３のアルキルチオ基、ハロゲン原子で置換されていてもよい炭素数１〜３のアルコキシル基が結合したメチル基、水素原子またはハロゲン原子を表す。）
で示されるベンジルアルコール化合物とをエステル交換反応して得られる、式（IV）で示されるベンジルエステル化合物を含む粗生成物を、精留塔を具備した蒸留装置にて水蒸気蒸留することを特徴とする精ベンジルエステル化合物の製造方法である。 The present invention provides a compound of formula (I)

(In the formula, R ¹ represents a methyl group or an alkenyl group having 3 to 4 carbon atoms, R ² represents a hydrogen atom or a methyl group, and R ³ represents a methyl group or an ethyl group.)
An ester compound represented by formula (II)

(In the formula, R ⁴ is an alkyl group having 1 to 3 carbon atoms which may be substituted with a halogen atom, an alkenyl group having 2 to 3 carbon atoms which may be substituted with a halogen atom, or a halogen atom. An alkoxyl group having 1 to 3 carbon atoms, an alkylthio group having 1 to 3 carbon atoms which may be substituted with a halogen atom, and an alkoxyl group having 1 to 3 carbon atoms which may be substituted with a halogen atom are bonded. Represents a methyl group, a hydrogen atom or a halogen atom.)
A crude product containing a benzyl ester compound represented by the formula (IV) obtained by transesterification with a benzyl alcohol compound represented by formula (IV) is subjected to steam distillation in a distillation apparatus equipped with a rectifying column. This is a method for producing a purified benzyl ester compound.

（式中、Ｒ^１、Ｒ^２及びＲ^４は前記と同じ意味を表す。）

(Wherein R ¹ , R ² and R ⁴ represent the same meaning as described above.)

Among them, the transesterification reaction has the formula (III)
R ⁵ OLi (III)
(In the formula, R ⁵ represents an alkyl group having 1 to 4 carbon atoms.)
The transesterification is preferably carried out in the presence of a lithium compound represented by formula (II) and an organic solvent that can be separated from water.

  Further, as the rectifying column provided in the distillation apparatus, it is preferable to use a rectifying column having 1 to 10 theoretical plates in the recovery section, and it is preferable to use a packed rectifying column as the rectifying column. Furthermore, in the steam distillation, it is preferable to use 1 to 10 parts by weight of steam with respect to 1 part by weight of the benzyl ester compound (IV) supplied to the distillation apparatus.

According to the present invention, even if a large amount of the cyclopropanecarboxylic acid 2,3,5,6-tetrafluorobenzyl ester compound represented by the formula (IV) is produced on an industrial scale, it can be obtained with high purity and high yield. The compound can be obtained.
Moreover, the weight of water vapor used in the present invention can be significantly reduced compared to the weight of water used in conventional azeotropic distillation, and industrially important energy consumption can be reduced.

Hereinafter, the present invention will be described in detail.
Examples of the alkenyl group having 3 to 4 carbon atoms represented by R ¹ in the ester compound (I) used in the present invention include 2-methyl-1-propenyl group, 1-propenyl group and 1-butenyl group. It is done.
Examples of the ester compound (I) include compounds in which R ¹ is an alkenyl group having 3 to 4 carbon atoms and R ₂ is a hydrogen atom, and compounds in which R ¹ and R ₂ are both methyl groups. .

  Specific examples of the ester compound (I) include methyl 2,2-dimethyl-3- (2-methyl-1-propenyl) cyclopropanecarboxylate and 2,2-dimethyl-3- (1-propenyl) cyclopropanecarboxylic acid. Acid methyl, methyl 2,2-dimethyl-3- (1-butenyl) cyclopropanecarboxylate, methyl 2,2,3,3-tetramethylcyclopropanecarboxylate, 2,2-dimethyl-3- (2-methyl) -1-propenyl) ethyl cyclopropanecarboxylate, ethyl 2,2-dimethyl-3- (1-propenyl) cyclopropanecarboxylate, ethyl 2,2-dimethyl-3- (1-butenyl) cyclopropanecarboxylate, and Examples include ethyl 2,2,3,3-tetramethylcyclopropanecarboxylate.

Examples of the alkyl group having 1 to 3 carbon atoms which may be substituted with a halogen atom and represented by R ⁴ in the benzyl alcohol compound (II) include a methyl group, an ethyl group and a trifluoromethyl group. Examples of the alkenyl group having 2 to 3 carbon atoms which may be substituted with a halogen atom represented by R ⁴ include a vinyl group, an allyl group and a 2,2-dichlorovinyl group. Examples of the alkoxy group having 1 to 3 carbon atoms which may be substituted with a halogen atom represented by R ⁴ include a methoxy group and a trifluoromethoxy group. Examples of the alkylthio group having 1 to 3 carbon atoms which may be substituted with a halogen atom represented by R ⁴ include a methylthio group. Examples of the methyl group represented by R ⁴ and bonded with an alkoxyl group having 1 to 3 carbon atoms which may be substituted with a halogen atom include a methoxymethyl group. Examples of the halogen atom include a fluorine atom, a chlorine atom, and a bromine atom.

  Specific examples of the benzyl alcohol compound (II) include 2,3,5,6-tetrafluorobenzyl alcohol, 2,3,4,5,6-pentafluorobenzyl alcohol, 2,3,5,6-tetrafluoro. -4-chlorobenzyl alcohol, 2,3,5,6-tetrafluoro-4-bromobenzyl alcohol, 2,3,5,6-tetrafluoro-4-methylbenzyl alcohol, 2,3,5,6-tetra Fluoro-4-difluoromethylbenzyl alcohol, 2,3,5,6-tetrafluoro-4-trifluoromethylbenzyl alcohol, 2,3,5,6-tetrafluoro-4-vinylbenzyl alcohol, 2,3,5 , 6-tetrafluoro-4-allylbenzyl alcohol, 2,3,5,6-tetrafluoro-4- (2,2-dichlorovinyl ) Benzyl alcohol, 2,3,5,6-tetrafluoro-4-methoxybenzyl alcohol, 2,3,5,6-tetrafluoro-4-difluoromethoxybenzyl alcohol, 2,3,5,6-tetrafluoro- Examples include 4-trifluoromethoxybenzyl alcohol, 2,3,5,6-tetrafluoro-4-methylthiobenzyl alcohol, and 2,3,5,6-tetrafluoro-4-methoxymethylbenzyl alcohol.

Examples of the ester compound represented by the formula (IV) include compounds in which R ¹ is an alkenyl group having 3 to 4 carbon atoms and R ² is a hydrogen atom, and R ¹ and R ² are both methyl groups. Compounds.

In the present invention, first, a crude product containing a benzyl ester compound represented by the formula (IV) is produced by transesterifying an ester compound (I) and a benzyl alcohol compound (II).
The amount of ester compound (I) used in the transesterification reaction is preferably in the range of 1 to 3 moles with respect to 1 mole of benzyl alcohol compound (II) in order to facilitate separation and recovery after the reaction. More preferably, it is the range of 1-2 mol.
As the transesterification, for example, an ester compound (I) and a benzyl alcohol compound (II) can be separated from water in an organic solvent (hereinafter sometimes referred to as an organic solvent) and a lithium compound (III). The method of transesterification is mentioned. Hereinafter, a method for transesterification in the presence of an organic solvent and a lithium compound (III) will be described.

The lithium compound (III) used in the transesterification reaction is a compound represented by the following formula.
R ⁵ OLi (III)
In the formula, examples of the alkyl group having 1 to 4 carbon atoms represented by R ⁵ include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, and a t-butyl group.
Specific examples of the lithium compound (III) include lithium methoxide, lithium ethoxide, lithium propoxide, lithium isopropoxide, and lithium-t-butoxide.
The amount of the lithium compound (III) used is preferably in the range of 0.001 to 0.1 mol with respect to 1 mol of the benzyl alcohol compound (II).

Examples of the organic solvent include halogenated hydrocarbons (1,2-dichloroethane, etc.), aliphatic hydrocarbons (hexane, cyclohexane, heptane, octane, nonane, etc.), aromatic hydrocarbons (toluene, xylene, chlorobenzene, benzoate). Trifluoride, 1,3-bis (trifluoromethyl) benzene and the like) and ethers (diethylene glycol dimethyl ether and the like).
The amount of the organic solvent is usually 0.5 to 100 parts by weight, preferably 1 to 10 parts by weight with respect to 1 part by weight of the benzyl alcohol compound (II). When the organic solvent is used in an amount of 0.5 parts by weight or more, it is preferable because side reactions other than the transesterification reaction tend to be suppressed, and when it is 100 parts by weight or less, the conversion rate of the reaction tends to be improved.

The transesterification reaction is usually carried out by heating to the boiling point of the product alcohol derived from R ³ , usually 70 to 200 ° C., and removing the product alcohol out of the reaction system. Specifically, for example, (a) a method of evaporating and removing only the generated alcohol using an organic solvent having a boiling point higher than the reaction temperature, and (a) a generated alcohol using an organic solvent having a boiling point of about the reaction temperature or less. And a method of evaporating and removing the organic solvent at the same time.
Among them, the method (a) is preferable because alcohol can be removed quickly and easily.
As the method (a), (b-1) the vapor mixture of the organic solvent and alcohol evaporated and removed from the transesterification reaction solution is condensed in a condenser, and the liquefied liquid mixture is mixed with an aqueous phase and an organic solvent phase. (B) the mixed vapor of the organic solvent and alcohol evaporated and removed from the transesterification reaction solution is condensed in a condenser and liquefied. For example, a method of removing the mixed liquid as it is out of the system can be used. Among these, the method (A-1) is preferable because the amount of the organic solvent used can be reduced.
In the method (A-1), the produced alcohol is removed because it is extracted into the aqueous phase.
In (A-1), it is preferable to use a rectifying column before the condenser because the generated alcohol can be efficiently removed, the reaction rate is increased, and the yield tends to be improved. .

As a specific example, the method (b-1) using a rectifying column as an apparatus for transesterification of the present invention will be described below with reference to FIG. Since the transesterification reaction is an equilibrium reaction, the reaction rate can be increased and the yield can be improved by efficiently removing the produced alcohol.
In the reaction vessel (10) having the rectification column (11), the ester compound (I), the benzyl alcohol compound (II), the lithium compound (III) and the organic solvent are mixed. The obtained solution is heated to a temperature equal to or higher than the boiling point of the alcohol, usually about the boiling point of the organic solvent, the mixed solvent of the alcohol and the organic solvent is evaporated, and the reaction tank (10) is passed through the rectification column (11). Then, it is condensed by a condenser (12) that can cool the condensate to about 50 ° C. or less, and reaches a liquid separation tank (13).
Since the separation tank (13) is usually filled with water, most of the alcohol contained in the condensate is extracted into the aqueous phase (14), and the organic solvent not dissolved in water is the organic solvent phase (15). Form. Usually, the organic solvent phase (15) having a small specific gravity is refluxed from the upper part of the separation tank (13) to the rectification column (11). Inside the rectification column (11), a part of the distillate (high boiling component: mainly organic solvent) is returned to the reaction tank (10), and a part (low boiling component: mainly produced alcohol) is further distilled. The distillate is condensed in the condenser (12) and reaches the liquid separation tank (13). Thus, since the reflux liquid refluxed from the rectification column (11) to the reaction tank (10) is mostly an organic solvent having a high boiling point, the alcohol concentration in the reaction tank (10) is lowered. This facilitates evaporation removal of the produced alcohol from the reaction tank (10). As a result, the use of a rectifying column increases the reaction rate and improves the yield.

Here, the number of theoretical plates of the rectification column (11) may be one or more, but is usually about 1 to 10 and preferably about 3 to 8. Examples of the rectifying column (11) include rectifying columns such as a plate type and a packed type. Among them, the packed type is preferable because the removal efficiency of low boiling components is better.
As the packing used in the packed rectification column, a commercially available packing may be used, for example, Raschig ring, Berle saddle, pole ring, interlock saddle, Lessing ring, Terralet, McMahon packing, Canon packing, Dixon packing. And irregular fillers such as Sulzer BX, Merapack, Flexipack, and Gempack.

After completion of the transesterification reaction, the reaction solution is washed with water or alkaline water, and further washed with acidic water as necessary to obtain an oil phase containing a crude product of the benzyl ester compound (IV) and an organic solvent. it can.
The present invention is a method for producing a purified benzyl ester compound by steam distillation of this oil phase.
Examples of the distillation apparatus for carrying out the steam distillation include, for example, a batch-type distillation apparatus in which steam is blown directly into a distillation tank equipped with a rectifying column, and continuous supply of water vapor and a reaction solution to the rectifying column to make countercurrent contact. Although a countercurrent distillation apparatus etc. are mentioned, a continuous countercurrent distillation apparatus is preferable because the amount of water vapor used is reduced and, as a result, energy consumption is reduced.
A preferred embodiment of steam distillation will be described below based on a continuous countercurrent distillation apparatus shown in FIG.

Water vapor (22) is supplied from the lower part of the rectification column (20) whose pressure is adjusted under normal pressure or reduced pressure, preferably under a reduced pressure of about 0.05 to 0.1 MPa. The oil phase (21) is supplied from the upper part of the rectification column, and the oil phase (21) and the water vapor (22) are brought into countercurrent contact in the rectification column. The amount of water vapor used is usually about 1 to 10 parts by weight with respect to 1 part by weight of the benzyl ester compound (IV) contained in the supplied oil phase (21).
Impurities, organic solvents, and water vapor are generally discharged as gas from the top (23) of the rectification column, and collected by condensation and cooling in the condenser (25). The purified benzyl ester compound (IV) and moisture are discharged as a liquid from the bottom (24) of the rectifying column.

The rectifying column (20) provided in the distillation apparatus may have a theoretical plate number of 1 or more, but is usually about 1 to 10 and preferably about 3 to 8. The rectifying column (20) includes, for example, a rectifying column such as a plate type or a packed type, and the packed type has a better removal efficiency of low boiling components (low boiling point impurities and organic solvents). To preferred.
As the packing used for the packed rectification column, the same packing as the rectification column (11) used for the transesterification reaction can be used.

The component discharged from the bottom (24) of the rectifying column is separated into water by a method such as liquid separation, and the organic solvent is removed as necessary, whereby a high content of the benzyl ester compound (IV), that is, A pure benzyl ester compound can be obtained.
Moreover, the component discharged | emitted from the tower | column top part (23) of a rectification tower | column can collect | recover an organic solvent by rectifying after removing a water | moisture content by liquid separation.

  Hereinafter, the present invention will be described in detail with reference to production examples, but the present invention is not limited to these examples. The reactor numbers correspond to those in FIGS. Moreover, in the comparative example, the azeotropic distillation used the transesterification reaction tank shown in FIG. 1 as it was.

<Transesterification>
200L of a rectifying column (11) having a diameter of 6 mm filled with a packing (McMahon packing) having a size of 6 mm and a height of 900 mm and a separation tank (13) containing water in advance are connected as shown in FIG. The reaction vessel (10) was charged with 22.5 kg of methyl 2,2-dimethyl-3- (1-propenyl) cyclopropanecarboxylate (I-1), 90 kg of normal heptane, 2,3,5,6-tetrafluoro-4- 25.4 kg of methoxymethylbenzyl alcohol (II-1) was charged. Subsequently, 0.10 kg of lithium methoxide (III-1) was charged, and the reaction solution in the reaction vessel (10) was kept at 95 to 105 ° C. During the heat retention, the component distilled from the top of the rectification column is cooled to about 30 ° C. by the condenser (12), and the resulting condensate reaches the liquid separation tank (13) and the water phase (14 ) And the organic solvent phase (15). The organic solvent phase (15) was refluxed to the top of the rectification column. The reaction tank (10) was kept warm and refluxed from the separation tank (13) for about 16 hours. Thereafter, the mixture was cooled and washed sequentially with a 5% aqueous sodium hydroxide solution and water to obtain 99.0 kg of an oil phase.

<Steam distillation>
Next, steam at 100 ° C. was fed at 23.3 kg / Hr from the lower part (22) of the rectification tower (20) having a diameter of 150 mm and packed with a packing (Raschig ring) having a size of 13 mm at a height of 680 mm. The oil phase washed from the upper part (21) of the rectification column was fed at 6.4 kg / Hr (see FIG. 2).
The oil phase is separated from the can obtained from the bottom (24) of the rectifying column (20), followed by dehydration, whereby the desired 2,2-dimethyl-3- (1-propenyl) cyclohexane is obtained. 37.0 kg of a pure benzyl ester compound containing propanecarboxylic acid 2,3,5,6-tetrafluoro-4-methoxymethyl-benzyl (IV-1) was obtained. When this purified benzyl ester compound was analyzed by an internal standard method using gas chromatography, the content of (IV-1) was 97.2%. The yield of (IV-1) was 89.6% based on 2,3,5,6-tetrafluoro-4-methoxymethylbenzyl alcohol (II-1). The amount of water (steam) used for steam distillation was 8.9 times by weight with respect to (IV-1) contained in the purified benzyl ester compound.

(Example 2)
<Transesterification>
In the same reactor as in Example 1, 6.72 kg of methyl 2,2-dimethyl-3- (1-propenyl) cyclopropanecarboxylate (I-1), 2,3,5,6-tetrafluoro-4-methyl A transesterification reaction was carried out in the same manner as in Example 1 except that 8.00 kg of benzyl alcohol (II-2), about 25.7 kg of normal heptane, and 0.04 kg of lithium methoxide (III-1) were used. 3 kg was obtained.

<Steam distillation>
Similarly to Example 1, 100 ° C. water vapor was fed at 18.9 kg / Hr from the lower part (22) of the rectifying column (20), and at the same time, the oil phase after washing was fed from the upper part of the rectifying column (21) to 9 By feeding at 5 kg / Hr and carrying out in the same manner as in Example 1, separating the oil phase from the can liquid obtained from the bottom (24) of the rectification column (20), followed by dehydration. 12.8 kg of a benzyl ester compound containing 2,2-dimethyl-3- (1-propenyl) cyclopropanecarboxylic acid 2,3,5,6-tetrafluoro-4-methoxymethyl-benzyl (IV-2) Obtained. The results are summarized in Table 1 together with Example 1.

(Comparative Example 1)
<Transesterification>
Made of 8000L SUS316L equipped with a rectification tower (11) with a diameter of 900 mm and a packing height of 6650 mm (sulzer packed column, packed with Melapack 350Y) and a separation tank (13) containing water as shown in FIG. To the reaction vessel (10), 524.6 kg of methyl 2,2-dimethyl-3- (1-propenyl) cyclopropanecarboxylate (I-1), about 2400 kg of normal heptane, 2,3,5,6-tetrafluoro- 4-Methoxymethylbenzyl alcohol (II-1) 604.8 kg was charged.
Subsequently, 2.53 kg of lithium methoxide (III-1) was charged, and the reaction solution in the reaction vessel (10) was kept at 95 to 105 ° C. During the heat retention, the component distilled from the top of the rectifying column was cooled to about 30 ° C. by the condenser (12) and sent to the separation tank (13). The organic solvent phase (15) of the separation tank (13) was refluxed to the upper part of the rectification column. The reaction tank (10) was kept warm and refluxed from the separation tank (13) for about 17 hours. Thereafter, it was washed successively with a 5% aqueous sodium hydroxide solution and water to obtain 3404 kg of an oil phase.

<Azeotropic distillation>
The obtained oil phase was concentrated in a concentration tank (not shown), about 1900 kg of normal heptane was distilled off, 5101 kg of water was added, and then heated to 65 ° C. under a reduced pressure of 25 kPa to distill 3061 kg. I let you. Next, 2976 kg of water was added and heated to 65 ° C. under reduced pressure at 25 kPa and distilled to 3016 kg. Further, 2976 kg of water was added and heated to 65 ° C. under reduced pressure to 25 kPa and distilled to 3004 kg. After cooling, the oil phase is separated from the resulting kettle residue, followed by evaporation of the water under reduced pressure, and 2,2-dimethyl-3- (1-propenyl) cyclopropanecarboxylic acid 2,3,5 868 kg of a benzyl ester compound containing 1,6-tetrafluoro-4-methoxymethylbenzyl (IV-1) was obtained. The results are summarized in Table 1.

(Comparative Example 2)
<Transesterification>
Methyl 2,2-dimethyl-3- (1-propenyl) cyclopropanecarboxylate (I-1) 349.6 kg, 2,3,5,6-tetrafluoro-4-methylbenzyl alcohol (II-2) 355. Transesterification was carried out in the same manner as in Comparative Example 1 except that 6 kg and 1.67 kg of lithium methoxide (III-1) were used, and about 1501 kg of an oil phase was obtained.

<Azeotropic distillation>
After concentrating the obtained oil phase in a concentrating tank and distilling off 524 kg of normal heptane, as in Comparative Example 1, 4913 kg of water was added and heated to 65 ° C. under reduced pressure at 25 kPa to distill 3645 kg. After that, 3439 kg of water was further added and heated to 25 kPa under reduced pressure at 65 ° C. to distill 3268 kg. The oil phase is separated from the obtained residue, and then water is evaporated under reduced pressure to give 2,2-dimethyl-3- (1-propenyl) cyclopropanecarboxylic acid 2,3,5,6- 561 kg of a purified benzyl ester compound containing tetrafluoro-4-methoxymethylbenzyl (IV-2) was obtained. The results are summarized in Table 1.

１）目的物に対する、水蒸気蒸留または共沸蒸留で使用した水の量
２）ベンジルアルコール
（II）に対する目的物の収率
３）精ベンジルエステル化合物に含まれる目的物の重量百分率

1) Amount of water used in steam distillation or azeotropic distillation with respect to the target product 2) Yield of target product with respect to benzyl alcohol (II) 3) Weight percentage of target product contained in purified benzyl ester compound

  INDUSTRIAL APPLICABILITY The present invention is used in a method for producing a purified cyclopropanecarboxylic acid benzyl ester compound used for agricultural chemicals such as pest control agents, pharmaceuticals such as pharmaceuticals, industrial chemicals and the like.

It is one embodiment of the reaction apparatus used for transesterification. It is one embodiment of the reaction apparatus used for steam distillation.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Reaction tank for transesterification reaction 11 Rectifying tower for transesterification reaction 12 Condenser for transesterification reaction 13 Separation tank 14 Water phase 15 Organic solvent phase 20 Fractionation tower used for steam distillation 21 Transesterification reaction The crude product containing the benzyl ester compound obtained by the process 22 Steam supplied to the steam distillation 23 Tower top of the rectification tower used for steam distillation 24 Bottom of the rectification tower used for steam distillation 25 Distillation by steam distillation For low boiling components

Claims (5)

Formula (I)

(In the formula, R ¹ represents a methyl group or an alkenyl group having 3 to 4 carbon atoms, R ² represents a hydrogen atom or a methyl group, and R ³ represents a methyl group or an ethyl group.)
An ester compound represented by formula (II)

(In the formula, R ⁴ is an alkyl group having 1 to 3 carbon atoms which may be substituted with a halogen atom, an alkenyl group having 2 to 3 carbon atoms which may be substituted with a halogen atom, or a halogen atom. An alkoxyl group having 1 to 3 carbon atoms, an alkylthio group having 1 to 3 carbon atoms which may be substituted with a halogen atom, and an alkoxyl group having 1 to 3 carbon atoms which may be substituted with a halogen atom are bonded. Represents a methyl group, a hydrogen atom or a halogen atom.)
A crude product containing a benzyl ester compound represented by the formula (IV) obtained by transesterification with a benzyl alcohol compound represented by formula (IV) is subjected to steam distillation in a distillation apparatus equipped with a rectifying column. A method for producing a purified benzyl ester compound.

(Wherein R ¹ , R ² and R ⁴ represent the same meaning as described above.) The transesterification reaction is of formula (III)
R ⁵ OLi (III)
(In the formula, R ⁵ represents an alkyl group having 1 to 4 carbon atoms.)
The production method according to claim 1, wherein the transesterification reaction is performed in the presence of a lithium compound represented by the formula (1) and an organic solvent that can be separated from water.   The method according to claim 1 or 2, wherein a rectifying column having 1 to 10 theoretical plates in the recovery section is used as the rectifying column provided in the distillation apparatus.   The production method according to any one of claims 1 to 3, wherein a packed rectification column is used as the rectification column.   In the steam distillation, 1 to 10 parts by weight of steam is used with respect to 1 part by weight of the benzyl ester compound (IV) supplied to the distillation apparatus. .

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