KR20090057337A - Process for preparing tetrafluorobenzene carbaldehyde alkyl acetal - Google Patents

Abstract

A process for preparing tetrafluorobenzene carbaldehyde alkyl acetal represented by the following formula (II), comprising reducing tetrafluorocyanobenzene represented by the following formula (I) with a metal catalyst containing a platinum group metal in the presence of an alkyl alcohol represented by R-OH (R is an alkyl group of 1 to 4 carbon atoms) and an acid; (I) wherein m is 1 or 2, n is 0 or 1, and m+n is 2, (II) wherein m and n are the same as those in the formula (I), and R is an alkyl group of 1 to 4 carbon atoms.

Description

Process for producing tetrafluorobenzene carbaldehyde alkylacetal {PROCESS FOR PREPARING TETRAFLUOROBENZENE CARBALDEHYDE ALKYL ACETAL}

The present invention provides a method for preparing tetrafluorobenzene carbaldehyde alkylacetal represented by formula (II), which is useful as a raw material for manufacturing pesticides, pharmaceuticals, and the like, and tetrafluorobenzene carbal represented by formula (III) by hydrolysis of acetal. After dehydroconversion, it is related with the manufacturing method of tetrafluorobenzene carbaldehyde which is refine | purified by extracting with the solvent isolate | separated from two layers with water.

<Formula II>

(Wherein m is 1 or 2, n is 0 or 1, m + n = 2, and R represents an alkyl group having 1 to 4 carbon atoms)

<Formula III>

(Wherein m and n represent the same as the general formula (II))

More specifically, the present invention relates to a method in which tetrafluorobenzene carbaldehyde alkylacetals, which are useful as intermediates of cyclopropanecarboxylic acid esters having excellent insecticidal action, are reacted by using tetrafluorocyanobenzene as a raw material. After hydrolyzing the obtained method and the obtained acetal, it is related with the method of refine | purifying by a simple method, and producing tetrafluorobenzene carbaldehyde of high purity.

Conventionally, as a method for producing tetrafluorobenzene carbaldehyde alkylacetals, for example, a method for producing by tetrafluorodicyanobenzene by reduction using a sponge nickel catalyst (Patent Document 1, Non-Patent Document 1) ) Is disclosed. According to these documents, although the target compound can be manufactured, since the sponge nickel which is a catalyst is added in sulfuric acid, a catalyst melt | dissolves and the usage-amount of a catalyst increases. In addition, there is a problem that it is impossible to repeatedly use the dissolved catalyst, and the reaction yield is not so high. As another method of manufacturing tetrafluorobenzene carbaldehyde, the method of reducing and hydrolyzing from tetrafluoro dicyano benzene using a sponge nickel catalyst in presence of water (patent document 2), etc. are disclosed. This method is also the same as the above problem because the catalyst is sponge nickel and is a reaction in sulfuric acid.

[Patent Document 1] International Publication WO 00/68173

[Patent Document 2] Japanese Patent Application Laid-Open No. 2001-158754

[Non-Patent Document 1] Journal of Fluorine Chemistry, 125, 451-454, 2004

<Object of invention>

An object of the present invention is to provide a manufacturing method capable of industrially advantageously producing a tetrafluorobenzene carbaldehyde alkylacetal compound and a tetrafluorobenzene carbaldehyde compound useful as a raw material for manufacturing pesticides, medicines, and the like. It is done.

Summary of the Invention

MEANS TO SOLVE THE PROBLEM As a result of earnestly examining, the present inventors can manufacture the target compound with high yield and high purity by using tetrafluorocyano benzene as a raw material and reducing it using the metal catalyst containing a platinum group metal as a catalyst, It has been found that this can be solved and the present invention has been completed.

The present invention includes the following matters.

[1] a tetrafluorocyanobenzene represented by the following formula (I), containing a platinum group metal in the presence of an alkylalcohol and an acid represented by R-OH (wherein R represents an alkyl group having 1 to 4 carbon atoms); A method for producing tetrafluorobenzene carbaldehyde alkylacetal represented by the following formula (II), which comprises reducing with a metal catalyst.

<Formula I>

(Wherein m is 1 or 2, n is 0 or 1 and m + n = 2)

<Formula II>

(Wherein m and n represent the same as those of the general formula (I), and R represents an alkyl group having 1 to 4 carbon atoms)

[2] The method for producing tetrafluorobenzene carbaldehyde alkylacetal according to the above [1], wherein the metal catalyst containing a platinum group metal is pretreated at 100 ° C. or lower in a hydrogen atmosphere in a solvent.

[3] The method for producing tetrafluorobenzene carbaldehyde alkylacetal according to the above [1] or [2], wherein the amount of the acid used is 1 mol% to 10 mol% with respect to the nitrile group of tetrafluorocyanobenzene.

[4] The method for producing tetrafluorobenzene carbaldehyde alkylacetal according to any one of [1] to [3], wherein the hydrogen reduction is performed at a reaction temperature of 30 to 100 ° C. and a hydrogen partial pressure atmospheric pressure to 1.5 MPa.

[5] Tetrafluorobenzene carbaldehyde hydrochloride represented by the following general formula (III) by adding water to the tetrafluorobenzene carbaldehyde alkylacetal represented by the following general formula (II) and hydrolyzing while separating alkyl alcohols by distillation And then purifying by extracting with a solvent separated by two layers with water.

<Formula II>

(Wherein m is 1 or 2, n is 0 or 1, m + n = 2, and R represents an alkyl group having 1 to 4 carbon atoms)

<Formula III>

(Wherein m and n represent the same as the general formula (II))

Effect of the Invention

In the production method of the present invention, a tetrafluorobenzene carbaldehyde alkylacetal compound and a tetrafluorobenzene carbaldehyde compound are obtained efficiently, and almost no by-products are produced. It is useful industrially because it can further reduce the load on the plant.

Best Mode for Carrying Out the Invention

Hereinafter, the present invention will be described in more detail.

Specific examples of the tetrafluorocyanobenzene represented by the formula (I) used in the production method of the present invention include tetrafluoromonocyanobenzenes (2,3,4,5-tetrafluoro benzonitrile, 2,3, 5,6-tetrafluorobenzonitrile, 2,3,4,6-tetrafluorobenzonitrile), tetrafluorodicyanobenzenes (3,4,5,6-tetrafluoroorthophthalonitrile, 2 , 4,5,6-tetrafluoroisophthalonitrile, 2,3,5,6-tetrafluoroterephthalonitrile).

Among these, tetrafluoro dicyano benzenes are preferable, and 2,3,5,6- tetrafluoro terephthalonitrile is used more preferably.

Some of these are commercially available and readily available. Moreover, it can synthesize | combine from terephthaloyl chloride by the method as described, for example in Journal of Fluorine Chemistry, 125, 451-454 (issued 2004).

In the production method according to the present invention, the tetrafluorocyanobenzene represented by the formula (I) is catalytically reduced with a metal catalyst containing a platinum group metal in the presence of an alkyl alcohol and an acid, and thus the tetra-fluoro represented by the formula (II). A method for producing a fluorobenzene carbaldehyde alkylacetal compound.

The reaction in the production method of the present invention is preferably carried out in a hydrocracking reaction using hydrogen in the presence of a catalyst in a solvent. Although a metal catalyst is mentioned as a catalyst to be used, The catalyst containing a platinum group metal is used preferably. Platinum group metals represent elements of ruthenium, rhodium, palladium, osmium, iridium, and platinum among the elements belonging to Group 8 of the periodic table (Iwanami Physics Dictionary, 4th Edition 984 pages). The form of the catalyst may be a metal state or may be used in a supported form.

The supported catalyst is a catalyst in which particles of fine metals or metal oxides containing at least one metal species are supported by high dispersion in a carrier such as silica, alumina, silica alumina, activated carbon, or diatomaceous earth, specifically, supported ruthenium-based A catalyst, a supported rhodium-based catalyst, a supported palladium-based catalyst, a supported osmium-based catalyst, a supported iridium-based catalyst and a supported platinum-based catalyst.

In addition, a supported catalyst modified by adding one or more of the above-described metal species and other metal species may be used, and specific examples thereof include a supported platinum-alumina catalyst and a supported palladium-renium-alumina catalyst. Can be.

As an example of a preferable catalyst, a supported palladium type catalyst, a supported rhodium type catalyst, a supported platinum type catalyst, etc. are mentioned. Among these catalysts, a supported rhodium-based catalyst is particularly preferable.

Next, the catalytic reduction reaction in this invention is demonstrated.

There is no restriction | limiting in particular in the quantity of the catalyst added at the time of reaction, Although it changes also with the form of a catalyst, In general, it is preferable to use a catalyst of 0.1 mass% or more with respect to tetrafluorocyano benzene of general formula (I). More preferably, it is 0.1-100 mass%, Especially preferably, it is 0.1-30 mass%. When the amount of the catalyst is less than 0.1% by mass, the reaction does not proceed smoothly, and since a large amount of raw materials remain, the conversion may not increase. On the other hand, when the amount of the catalyst exceeds 100% by mass, side reactions tend to proceed, and since the nitrile group may cause a hydrogenation decyano reaction or may be converted into an amino group with excessive hydrogenation, it is not preferable.

Pretreatment of the catalyst prior to the reduction reaction is preferred because it improves the activity and selectivity of the catalyst. Pretreatment of a catalyst can be performed by heat-stirring under hydrogen pressurization in a solvent. The hydrogen pressure is not particularly limited and can be implemented in a range under atmospheric pressure from hydrogen, but is preferably performed under a partial pressure of hydrogen of 1 MPa from atmospheric pressure. In addition, it is preferable to perform temperature in the range of 30-100 degreeC, especially in the range of 30-80 degreeC. Although it does not restrict | limit especially as a solvent used for catalyst pretreatment, For example, a saturated aliphatic or alicyclic hydrocarbon solvent, an aromatic hydrocarbon solvent, an alcoholic solvent, the ether solvent of an aliphatic or alicyclic hydrocarbon, and water. Specifically, as a saturated aliphatic or alicyclic hydrocarbon solvent, n-hexane, n-octane, isooctane, cyclohexane, etc. are mentioned, As an aromatic hydrocarbon solvent, benzene, toluene, xylene, etc. are mentioned, Alcohol Examples of the solvent include ether solvents of alcohols having 1 to 4 carbon atoms, aliphatic or alicyclic hydrocarbons such as methanol, ethanol, n-propanol, isopropanol, n-butanol, diethyl ether, diisopropyl ether and methyl-tert-butyl ether. And tetrahydrofuran, dioxane, dioxolane and the like. It is easy to use the solvent used at the time of a reduction reaction as it is, and preferable specific examples are methanol, ethanol, n-propanol, isopropanol, and n-butanol.

In the catalytic reduction reaction of the present invention, a solvent may be used. The solvent is not particularly limited, but preferred examples thereof include saturated aliphatic or alicyclic hydrocarbon solvents, aromatic hydrocarbon solvents, alcohol solvents, ether solvents of aliphatic or alicyclic hydrocarbons, and water. Specifically, as a saturated aliphatic or alicyclic hydrocarbon solvent, n-hexane, n-octane, isooctane, cyclohexane, etc. are mentioned, As an aromatic hydrocarbon solvent, benzene, toluene, xylene, etc. are mentioned, Alcohol solvents include methanol, ethanol, n-propanol, isopropanol, n-butanol and the like, and ether solvents of aliphatic or alicyclic hydrocarbons, such as diethyl ether, diisopropyl ether, and methyl tert-butyl. Ether, tetrahydrofuran, dioxane, dioxolane and the like.

These solvents can be used alone or as two or more types of mixed solvents. Moreover, when using as a mixed solvent, it can also be used in the state which is not mixed uniformly. Preferred solvents include toluene, methanol, dioxane and toluene-methanol, toluene-water, toluene-methanol-water and dioxane-water as mixed solvents. The amount of the solvent used is usually 0.5 to 30 mass times, preferably 1 to 20 mass times, relative to tetrafluorocyanobenzene. If the amount of solvent is less than 0.5 mass times, a problem may arise in heat removal. On the other hand, when it exceeds 30 mass times, since solvent distillation is needed at the time of isolate | separating a target object, too much too much is unnecessary.

Examples of the alkyl alcohol represented by the general formula R-OH (wherein R represents an alkyl group having 1 to 4 carbon atoms) used in the present invention include alkyl alcohols having 1 to 4 carbon atoms. Although methanol, ethanol, n-propanol, isopropanol, n-butanol, etc. are specifically used, methanol with a small steric hindrance is most preferable in order to promote an acetalization reaction. The alcohol is used at least 2 times mole with respect to the nitrile group of tetrafluorocyanobenzene of the formula (I), but it is preferably used at least 10 times mole.

In the present invention, an acid is required. Examples of the acid used may include sulfuric acid, hydrochloric acid, phosphoric acid, formic acid, acetic acid, monochloroacetic acid, dichloroacetic acid, trifluoroacetic acid, and the like, and sulfuric acid may be particularly preferably used. It is preferable to use the usage-amount of an acid within 1 to 10 times mole with respect to the nitrile group of tetrafluorocyano benzene of general formula (I). If the amount of acid is less than 1 molar, the imine produced at the time of the reaction cannot be stabilized, and the reaction may not proceed smoothly. Moreover, when it exceeds 10 times mole, since a catalyst may be inactivated by an acid, it is not preferable.

The catalytic reduction reaction of the present invention can be carried out by introducing hydrogen after introducing hydrogen into the gas phase and raising the reaction system to a predetermined temperature, or by replacing the gas phase with an inert gas and then raising the reaction system to a predetermined temperature. . There is no restriction | limiting in the supply method of hydrogen, You may blow into a reaction liquid, It may distribute | circulate or supply intermittently to a gaseous-phase part. The hydrogen gas used for this reaction does not necessarily need to be high purity, and may also contain an inert gas etc. which do not have a particularly influence on a hydrogenation reaction. Although reaction is normally performed at the temperature of 30-100 degreeC, Preferably it is carried out in 30-90 degreeC, More preferably, it is within the range of 50-80 degreeC. When the temperature is low, by-product hydrogenation and denitrile reaction of the amine proceed due to the addition of excess hydrogen, and the yield of the target product may be lowered. On the contrary, when reaction temperature is high, a catalyst may be inactivated by an acid, a hydrogen absorption rate may fall, and the yield of a target object may fall as a result. In the present invention, the hydrogen partial pressure at the reaction temperature is not particularly limited as long as the reaction proceeds. However, the hydrogen partial pressure is preferably low in order to suppress the by-products of the amine and excess nitrile reaction due to excessive hydrogenation. Preferably from atmospheric pressure to 1.5 MPa, more preferably from atmospheric pressure to 0.9 MPa, particularly preferably from atmospheric pressure to 0.5 MPa.

Although the reaction format is not specifically limited, Methods, such as a catalyst suspension flow type, a fixed bed flow type, a trickle head, or a batch type, can be used.

The tetrafluorobenzene carbaldehyde alkylacetal of the formula (II) produced by the reduction reaction of the present invention can be isolated and purified by filtration fractionation of the catalyst after the reaction, distillation of the solvent, extraction, recrystallization and the like.

The tetrafluorobenzene carvaldehydrohydrochloride represented by the general formula (III) can be converted by hydrolysis of the tetrafluorobenzene carbalaldehyde alkylacetal of the general formula (II) in the presence of water and an acid. Although there is no restriction | limiting in particular in the quantity of water, 2 times mole or more is necessary with respect to the nitrile group of tetrafluorocyano benzene of general formula (I). In order to advance the reaction smoothly, excess water may be used.

In the hydrolysis reaction, the so-called reactive distillation, which transfers the equilibrium to the product side by distilling off the alcohol contained in the raw material and the alcohol produced in the reaction, efficiently removes the contained tetrafluorobenzene carbaldehyde alkylacetal of formula (II). It is possible to convert the tetrafluorobenzene carbaldehyde represented by the formula (III). According to this reactive distillation, since the equilibrium can be efficiently shifted to the product side, the amount of acid and water used for the hydrolysis reaction can be greatly reduced.

The tetrafluorobenzene carbaldehyde represented by the general formula (III) obtained by the hydrolysis reaction can be purified by a method such as distillation, extraction, two-layer separation, etc., but extraction with an organic solvent is preferred because it is simple. The solvent to be extracted is not particularly limited as long as it is a solvent separated from water, and examples thereof include saturated aliphatic or alicyclic hydrocarbon solvents, aromatic hydrocarbon solvents, ether solvents of aliphatic or alicyclic hydrocarbons, and saturated aliphatic halogen solvents. And aromatic hydrocarbons such as toluene are preferably used.

EXAMPLES Hereinafter, although an Example is shown and this invention is demonstrated in detail, this invention is not limited by these description.

In addition, the analysis equipment and analysis conditions used in the Example are as follows.

Gas chromatography analysis (hereinafter referred to as "GC analysis")

Analytical Instruments: HP6850, manufactured by HP Corporation

Column: J & W Corporation DB-1, 30 m × 0.32 mm × 1 μm

Column temperature: 80 ° C., 5 ° C./min to 200 ° C., 15 ° C./min to 290 ° C., 11 min hold

Integrator: HP3396

Injection temperature: 300 ℃

Detector temperature: 300 ℃

Flow rate: constant pressure 7.91 psi (68.5 ml / min at 80 ° C.)

Split ratio: 50

Detector: FID, H ₂ 30 ml / min, air 300 ml / min

Carrier Gas: He

Gas chromatography quantitative analysis (hereinafter referred to as "GC quantitative analysis")

Internal standard: 1,2-dichlorobenzene

<Example 1>

20.6 g of 95% sulfuric acid was slowly added dropwise to 70 g (2.2 mol) of methanol in an Erlenmeyer flask under ice-cooling. In a 300 ml glass autoclave, a sulfuric acid / methanol solution and a 5% Rh / C catalyst (manufactured by NE Chemcat Corporation, water-containing product) were charged at 0.25 g in dry weight. Hydrogen substitution was carried out in the system, and the hydrogen pressure was 0.1 MPa at room temperature. Heating and stirring of the autoclave were initiated and held for 1 hour after reaching 40 ° C. After cooling, 10 g (50 mmol) of tetrafluoroterephthalonitrile (manufactured by Tokyo Kasei Kogyo Co., Ltd.) was added to the autoclave, and the temperature was raised to 70 ° C under a nitrogen atmosphere. The introduction of hydrogen at 70 ° C. was started. The reaction pressure was adjusted so that the hydrogen absorption rate was 10 ml / min or less. Absorption of hydrogen was stopped after 6 hours and 30 minutes. It was 119% of hydrogen absorption with respect to the theoretical hydrogen absorption amount. The reaction solution was filtered to filter out the catalyst, and methanol was distilled off at atmospheric pressure. Thereafter, 100 g of water was added to the remainder, and the mixture was heated to reflux at an internal temperature of 100 ° C. for 60 minutes, and then methanol produced by hydrolysis of acetal at atmospheric pressure was distilled off. Distillation was complete | finished when the top temperature of distillation reached 99 degreeC, and it cooled to room temperature, and extracted three times with 30 g of toluene.

A small amount of samples were taken from the toluene extract and subjected to GC analysis. As a result of analysis, the peak of tetrafluoroterephthalonitrile as a raw material was below the detection limit, 92.0 mol% of tetrafluoroterephthalaldehyde, 0.94 mol% of 2,3,5,6-tetrafluorobenzene, and 2,3, 5,6-tetrafluorobenzonitrile was 0.79 mol%. Meanwhile, the aqueous layer was neutralized and then subjected to GC analysis. As a result of analysis, 3.39 mol% of 2,3,5,6-tetrafluorobenzylamine was present. The results are shown in Table 1.

<Comparative Example 8>

In Example 1, it carried out similarly to Example 1 except having inject | poured 0.25 g of 5% Pd / C catalysts (the Chemtech Corporation make, water-containing product) in conversion of dry weight. Absorption of hydrogen was stopped after 3.3 hours. It was 117% of hydrogen absorption with respect to the theoretical hydrogen absorption amount. Treatment of the reaction solution was performed in the same manner as in Example 1.

A small amount of samples were taken from the toluene extract and subjected to GC analysis. As a result of the analysis, the peak of tetrafluoroterephthalonitrile as the starting material was below the detection limit, and the tetrafluoroterephthalaldehyde was 68.9 mol%. Meanwhile, the aqueous layer was neutralized and then subjected to GC analysis. As a result of analysis, 14.8 mol% of 2,3,5,6-tetrafluorobenzylamine was present. The results are shown in Table 1.

<Example 3>

In Example 1, it carried out similarly to Example 1 except having changed the hydrogen pretreatment temperature of the catalyst from 40 degreeC to 50 degreeC. Absorption of hydrogen was stopped after 5.5 hours. It was 106% of hydrogen absorption with respect to the theoretical hydrogen absorption amount. Treatment of the reaction solution was performed in the same manner as in Example 1.

A small amount of samples were taken from the toluene extract and subjected to GC analysis. As a result of analysis, the peak of tetrafluoroterephthalonitrile as a raw material was below the detection limit, 89.4 mol% of tetrafluoroterephthalaldehyde, 1.31 mol% of 2,3,5,6-tetrafluorobenzene, and 2,3, 5,6-tetrafluorobenzonitrile was 1.03 mol%. Meanwhile, the aqueous layer was neutralized and then subjected to GC analysis. As a result of the analysis, 2.35 mol% of 2,3,5,6-tetrafluorobenzylamine was present. The results are shown in Table 1.

<Example 4>

It carried out similarly to Example 1 except having changed the reaction temperature from 70 degreeC to 80 degreeC in Example 1. Absorption of hydrogen was stopped after 5.5 hours. It was 99% hydrogen absorption with respect to theoretical hydrogen absorption amount. Treatment of the reaction solution was performed in the same manner as in Example 1.

A small amount of samples were taken from the toluene extract and subjected to GC analysis. As a result of analysis, the peak of tetrafluoroterephthalonitrile as a raw material was below the detection limit, 87.5 mol% of tetrafluoroterephthalaldehyde, 2.00 mol% of 2,3,5,6-tetrafluorobenzene, and 2,3, 5,6-tetrafluorobenzonitrile was 1.61 mol%. Meanwhile, the aqueous layer was neutralized and then subjected to GC analysis. As a result of the analysis, 2.16 mol% of 2,3,5,6-tetrafluorobenzylamine was present. The results are shown in Table 1.

<Example 5>

The same procedure as in Example 1 was carried out except that the amount of sulfuric acid used in Example 1 was changed from 20.6 g to 12.9 g (125 mmol). After 7.0 hours, absorption of hydrogen was stopped. It was 73% hydrogen absorption with respect to the theoretical hydrogen absorption amount. Treatment of the reaction solution was performed in the same manner as in Example 1.

A small amount of samples were taken from the toluene extract and subjected to GC analysis. As a result of analysis, the peak of tetrafluoroterephthalonitrile as a raw material was below the detection limit, 84.5 mol% of tetrafluoroterephthalaldehyde, 1.00 mol% of 2,3,5,6-tetrafluorobenzene, and 2,3, 5,6-tetrafluorobenzonitrile was 0.83 mol%. Meanwhile, the aqueous layer was neutralized and then subjected to GC analysis. As a result of the analysis, 4.14 mol% of 2,3,5,6-tetrafluorobenzylamine was present. The results are shown in Table 1.

<Example 6>

The same procedure as in Example 1 was carried out except that the amount of tetrafluoroterephthalonitrile was changed from 10 g to 20 g (100 mmol) in Example 1. After 8.3 hours, absorption of hydrogen was stopped. It was 76% hydrogen absorption with respect to the theoretical hydrogen absorption amount. Treatment of the reaction solution was performed in the same manner as in Example 1.

A small amount of samples were taken from the toluene extract and subjected to GC analysis. As a result, the peaks of tetrafluoroterephthalonitrile as raw materials were below the detection limit, and 89.6 mol% of tetrafluoroterephthalaldehyde, 0.63 mol% of 2,3,5,6-tetrafluorobenzene, and 2,3 were detected. , 5,6-tetrafluorobenzonitrile was 0.54 mol%. Meanwhile, the aqueous layer was neutralized and then subjected to GC analysis. As a result of the analysis, 2.98 mol% of 2,3,5,6-tetrafluorobenzylamine was present. The results are shown in Table 1.

<Example 7>

Example 1, except that the catalyst used in Example 1 was changed from a 5% Rh / C catalyst (manufactured by Enchem Chem Corp., Water Products) to a 2% Rh / C catalyst (manufactured by Enchem Chem Corporation, Water Products) The same procedure was followed. After 7.3 hours, absorption of hydrogen was stopped. It was 114% hydrogen absorption with respect to the theoretical hydrogen absorption amount. Treatment of the reaction solution was performed in the same manner as in Example 1.

A small amount of samples were taken from the toluene extract and subjected to GC analysis. As a result of the analysis, the peak of tetrafluoroterephthalonitrile as a raw material was below the detection limit, and 88.6 mol% of tetrafluoroterephthalaldehyde was 1.15 mol% and 2,3, of 2,3,5,6-tetrafluorobenzene. 5,6-tetrafluorobenzonitrile was 2.63 mol%. Meanwhile, the aqueous layer was neutralized and then subjected to GC analysis. As a result of the analysis, 2.36 mol% of 2,3,5,6-tetrafluorobenzylamine was present. The results are shown in Table 1.

<Example 8>

After completion of the reaction in Example 1, the catalyst was recovered by filtration, and was carried out in the same manner as in Example 1 except that the recovered catalyst was used again. After 10.3 hours, absorption of hydrogen was stopped. It was 91% hydrogen absorption with respect to the theoretical hydrogen absorption amount. Treatment of the reaction solution was carried out in the same manner as in Example 1.

A small amount of samples were taken from the toluene extract and subjected to GC analysis. As a result, the peak of tetrafluoroterephthalonitrile as a raw material was below the detection limit, and 80.5 mol% of tetrafluoroterephthalaldehyde, 1.15 mol% of 2,3,5,6-tetrafluorobenzene, and 2,3, 5,6-tetrafluorobenzonitrile was below the detection limit. Meanwhile, the aqueous layer was neutralized and then subjected to GC analysis. As a result of the analysis, 2.88 mol% of 2,3,5,6-tetrafluorobenzylamine was present. The results are shown in Table 1.

Reference Example 1

It carried out similarly to Example 1 except having changed the amount of catalyst used in Example 1 from 0.25 g to 0.05 g in dry weight conversion. After 7.0 hours, absorption of hydrogen was stopped. It was 83% of hydrogen absorption with respect to the theoretical hydrogen absorption amount. Treatment of the reaction solution was performed in the same manner as in Example 1.

A small amount of samples were taken from the toluene extract and subjected to GC analysis. As a result of analysis, 21.0 mol% of tetrafluoro terephthalonitrile which is a raw material remained, and only 5.0 mol% of tetrafluoro terephthalaldehyde was obtained. 0.65 mol% of 2,3,5,6-tetrafluorobenzene, 0.53 mol% of 2,3,5,6-tetrafluorobenzonitrile, and 1-cyano-2 with only one nitrile group reacted; 63.1 mol% of 3,5,6- tetrafluorobenzaldehyde was obtained. Meanwhile, the aqueous layer was neutralized and then subjected to GC analysis. As a result of the analysis, 2.88 mol% of 2,3,5,6-tetrafluorobenzylamine was present. The results are shown in Table 2.

Reference Example 2

It carried out similarly to Example 1 except having used the catalyst used in Example 1 without performing hydrogen pretreatment. After 7.5 hours, absorption of hydrogen was stopped. It was 124% of hydrogen absorption with respect to the theoretical hydrogen absorption amount. Treatment of the reaction solution was performed in the same manner as in Example 1.

A small amount of samples were taken from the toluene extract and subjected to GC analysis. As a result, the peak of tetrafluoroterephthalonitrile as a raw material was below the detection limit, and 81.7 mol% of tetrafluoroterephthalaldehyde was 1.37 mol% and 2,3, of 2,3,5,6-tetrafluorobenzene. 5,6-tetrafluorobenzonitrile was 1.09 mol%. Meanwhile, the aqueous layer was neutralized and then subjected to GC analysis. As a result of the analysis, 7.29 mol% of 2,3,5,6-tetrafluorobenzylamine was present. The results are shown in Table 2.

Reference Example 3

The same procedure as in Example 1 was carried out except that the amount of sulfuric acid used in Example 1 was changed from 20.6 g to 5.15 g (50 mmol). After 4.2 hours, absorption of hydrogen was stopped. It was 47% of hydrogen absorption with respect to the theoretical hydrogen absorption amount. Treatment of the reaction solution was performed in the same manner as in Example 1.

A small amount of samples were taken from the toluene extract and subjected to GC analysis. As a result of the analysis, the peak of tetrafluoroterephthalonitrile as a raw material was below the detection limit, and only 14.5 mol% of tetrafluoroterephthalaldehyde was obtained. 1-cyano-2,3 in which 2,3,5,6-tetrafluorobenzene was 0.81 mol%, 2,3,5,6-tetrafluorobenzonitrile was 0.67 mol% and only one nitrile group was reacted. , 5,6-tetrafluorobenzaldehyde was obtained 54.0 mol%. Meanwhile, the aqueous layer was neutralized and then subjected to GC analysis. As a result of analysis, 0.04 mol% of 2,3,5,6-tetrafluorobenzylamine was present. The results are shown in Table 2.

Reference Example 4

It carried out similarly to Example 1 except having changed the reaction temperature from 70 degreeC to 120 degreeC in Example 1. After 8.0 hours, absorption of hydrogen was stopped. It was 103% hydrogen absorption with respect to theoretical hydrogen absorption amount. Treatment of the reaction solution was performed in the same manner as in Example 1.

A small amount of samples were taken from the toluene extract and subjected to GC analysis. As a result of the analysis, the peak of tetrafluoroterephthalonitrile as a raw material was below the detection limit, and only 2.6 mol% of tetrafluoroterephthalaldehyde was obtained. 1-cyano-2,3 in which 2,3,5,6-tetrafluorobenzene was 1.08 mol%, and 2,3,5,6-tetrafluorobenzonitrile was 0.87 mol% and only one nitrile group was reacted. 42.2 mol% of, 5,6- tetrafluorobenzaldehyde was obtained. Meanwhile, the aqueous layer was neutralized and then subjected to GC analysis. As a result, 2,3,5,6-tetrafluorobenzylamine was below the detection limit. The results are shown in Table 2.

Reference Example 5

It carried out similarly to Example 1 except having changed the reaction temperature from 70 degreeC to 20 degreeC in Example 1. After 7.0 hours, absorption of hydrogen was stopped. It was 124% of hydrogen absorption with respect to the theoretical hydrogen absorption amount. Treatment of the reaction solution was performed in the same manner as in Example 1.

A small amount of samples were taken from the toluene extract and subjected to GC analysis. As a result of the analysis, the peak of tetrafluoroterephthalonitrile as a raw material was below the detection limit, and only 42.2 mol% of tetrafluoroterephthalaldehyde was obtained. 2,3,5,6-tetrafluorobenzene was 1.75 mol%, and 2,3,5,6-tetrafluorobenzonitrile was 1.40 mol%. Meanwhile, the aqueous layer was neutralized and then subjected to GC analysis. As a result of analysis, 2,3,5,6-tetrafluorobenzylamine was 28.1 mol%. The results are shown in Table 2.

Comparative Example 6

In Example 1, as a catalyst to be used, a sponge nickel catalyst (R-239: manufactured by Nikko Rica Corporation) and 3 g of copper sulfate were added to the sulfuric acid / methanol solution, and the sponge nickel was coated with copper, and this catalyst was used. It carried out similarly to Example 1 except having used as. After 7.9 hours, absorption of hydrogen was stopped. It was 74% of hydrogen absorption with respect to the theoretical hydrogen absorption amount. Treatment of the reaction solution was performed in the same manner as in Example 1.

A small amount of samples were taken from the toluene extract and subjected to GC analysis. As a result of the analysis, the peak of tetrafluoroterephthalonitrile as a raw material was below the detection limit, and 67.0 mol% of tetrafluoroterephthalaldehyde was obtained. However, it was not possible to reuse the catalyst to proceed with the reaction again. The results are shown in Table 2.

Comparative Example 7

In the comparative example 6, it carried out similarly to the comparative example 6 except having changed the reaction temperature from 70 degreeC to 20 degreeC, and changing the quantity of copper sulfate from 3 g to 2 g. After 9.3 hours, absorption of hydrogen was stopped. The hydrogen absorption was 85% of the theoretical hydrogen uptake. Treatment of the reaction solution was performed in the same manner as in Example 1.

A small amount of samples were taken from the toluene extract and subjected to GC analysis. As a result of analysis, the peak of tetrafluoroterephthalonitrile as a raw material was below the detection limit, and 1-cyano-2,3,5,6-tetra with 23.9 mol% of trafluoroterephthalaldehyde and only one nitrile group reacted. 16.5 mol% of fluorobenzaldehyde was obtained. However, it was not possible to reuse the catalyst to proceed with the reaction again. The results are shown in Table 2.

Claims (1)

(1) A catalyst comprising rhodium in the presence of an alkylalcohol and an acid represented by R-OH (wherein R represents an alkyl group having 1 to 4 carbon atoms) in tetrafluorocyanobenzene represented by the following formula (I): Reduction to produce tetrafluorobenzene carbaldehyde alkylacetal represented by the following formula (II); <Formula I>

(Wherein m is 1 or 2, n is 0 or 1 and m + n = 2) <Formula II>

(Wherein m and n represent the same as those of the general formula (I), and R represents an alkyl group having 1 to 4 carbon atoms) (2) Tetrafluorobenzene carbaldehyde conversion represented by the following general formula (III) by hydrolysis by adding water to the tetrafluorobenzene carbaldehyde alkylacetal represented by the above formula (II) while separating alkyl alcohol by distillation And then purifying by extracting with a solvent separated by two layers with water. <Formula III>

(Wherein m and n represent the same as the general formula (II))