JPH11269104A - Production of 1,4-bis(difluoroalkyl)benzene derivative - Google Patents

Abstract

PROBLEM TO BE SOLVED: To produce the subject compound at a low cost in a simple process without requiring a special device, by reacting a specific compound with fluorine. SOLUTION: This method for producing a 1,4-bis(difluoroalkyl)benzene derivative of formula II [(k) is 0-4; G is a halogen, an alkyl, a perfluoroalkyl or an alkoxy; (m) is 0-4] comprises reacting a compound of formula l X1 -X4 are each oxygen or sulfur; Y1 and Y2 are each Cn H2n [(n) is 2 or 3]} with fluorine (for example, a fluorocompound such as hydrogen fluoride pyridine, cesium fluoride or hydrogen fluoride). The reaction is preferably carried out in the presence of a bromine compound (for example, N-bromosuccinimide, 1,3- dibromo-5,5-dimethylhydantoin) in an organic solvent (for example, dichloromethane, chloroform, 1,2-dichloromethane) in an atmosphere where the gaseous phase portion of the reaction system has a water content of <=100 vol ppm.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a method for producing a novel 1,4-bis (difluoroalkyl) benzene derivative. More specifically, the present invention relates to formula (1)
The compound represented by the formula (2) can be easily and inexpensively prepared by reacting the compound (A) represented by the formula (1) with fluorine at a low temperature and normal pressure, and has heat resistance, chemical resistance, water repellency, low dielectric property and low 1,4- useful as a raw material of resin having excellent refractive index
The present invention relates to a method for producing a bis (difluoroalkyl) benzene derivative.

[0002]

2. Description of the Related Art 1,4-Bis (difluoromethyl) benzene is used as a raw material to synthesize 1,4-bis (bromodifluoromethyl) benzene, and further used to prepare per-α-fluoro [2 .2] to paracyclophane, from which a fluorine-substituted parylene resin (PA-F) having excellent heat resistance, chemical resistance and water repellency can be synthesized. As a method for producing 1,4-bis (difluoromethyl) benzene, a method based on a reaction between terephthalaldehyde and sulfur tetrafluoride (SF ₄ ) [J. Am. Che
m. Soc., 82, p. 543-551 (1960)], and α, α,
Method by reaction of α ′, α′-tetrabromo-p-xylene with antimony trifluoride [RU2032654, Zh. Org. Khi
m., 29, p.1999-2001 (1993)].

[0003] Among these methods, the former method using sulfur tetrafluoride is highly toxic and corrosive, has a high price, and has a reaction condition of 150 ° C.
Since the conditions are as severe as 8 Mpa, special reaction vessels and the like using stainless steel (Ni-Mo based) Hastelloy or the like which is excellent in corrosion resistance are required, and there is a problem that the production cost increases. .

In addition, the latter reaction using antimony trifluoride requires heating at a high reaction temperature of 100 to 150 ° C., which also requires special equipment for the reaction, which increases the production cost. There is a problem.

[0005] Therefore, there is still a high demand for a method capable of producing 1,4-bis (difluoromethyl) benzene and its derivatives at a low cost by a simple operation without requiring special equipment.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to provide a novel method for producing a 1,4-bis (difluoroalkyl) benzene derivative in view of the above circumstances.

Another object of the present invention is to provide a method for producing a 1,4-bis (difluoroalkyl) benzene derivative at a low cost by a simple operation without requiring special equipment.

[0008]

Means for Solving the Problems The present inventors have made intensive studies in view of the above circumstances, and as a result, have found that the following formula (2) is obtained by reacting a compound (A) represented by the following formula (1) with fluorine. )
By producing the 1,4-bis (difluoroalkyl) benzene derivative represented by the formula (1), the reaction between compound (A) and fluorine can be carried out at low temperature and normal pressure, and the source of fluorine is relatively low. Because it is inexpensive, it does not require special equipment as in the past,
-It has been discovered that bis (difluoromethyl) benzene can be produced, and the present invention has been completed based on the above findings.

That is, the above objects are achieved by the following (A) to (D). (A) The following equation (1):

[0010]

Embedded image Provided that X ₁ , X ₂ , X ₃ and X ₄ are each independently
Represents an oxygen or sulfur atom; Y ₁ and Y ₂ each independently represent a group represented by —C _n H _2n —, wherein n
Is 2 or 3; k is an integer from 0 to 4; G represents a halogen group, an alkyl group, a perfluoroalkyl group or an alkoxy group; and m is an integer from 0 to 4;
Comprising reacting the compound (A) represented by the formula (I) with fluorine, the following formula (2):

[0011]

Embedded image A method for producing a 1,4-bis (difluoroalkyl) benzene derivative represented by the formula: (A) The production method according to (a), wherein the reaction between the compound (A) and fluorine is performed in the presence of an organic solvent. (C) The production method according to (A) or (A), wherein the reaction between the compound (A) and fluorine is performed in an atmosphere in which the water content of a gas phase portion of the reaction system is 100 volppm or less. (D) The production method according to any of (a) to (c), wherein the reaction between the compound (A) and fluorine is performed in the presence of a bromine-containing compound.

[0012]

DETAILED DESCRIPTION OF THE INVENTION The present invention will be described in detail below.

According to the present invention, a compound (A) represented by the following formula (1) is reacted with fluorine to obtain a 1,4-bis (difluoroalkyl) represented by the following formula (2).
It is characterized by producing a benzene derivative.

[0014]

Embedded image

[0015]

Embedded image In the above formula (1), X ₁ , X ₂ , X ₃ and X ₄ each independently represent any one of oxygen and sulfur atoms, preferably a sulfur atom. Further, Y ₁ and Y ₂ in the above formula (1) each independently represent a group represented by —C _n H _2n —, wherein n is 2 or 3, and the value of n is It is appropriately selected according to the reactivity between compound (A) and fluorine, but is preferably 2. In the above formulas (1) and (2), G represents a halogen group such as a fluoro group, a bromo group and a chloro group; an alkyl group having 1 to 4 carbon atoms, for example, a methyl group, an ethyl group and a propyl group. A perfluoroalkyl group having 1 to 4 carbon atoms such as trifluoromethyl group and pentafluoroethyl group; and an alkoxy group having 1 to 4 carbon atoms such as methoxy group, ethoxy group, perfluoromethoxy group and perfluoroalkyl group. And a fluoroethoxy group. Of these, G
Represents a halogen group such as a fluoro group, a bromo group and a chloro group, more preferably a fluoro group or a chloro group, and most preferably a fluoro group. At this time, when a plurality of Gs exist (that is, m is 2 to 4), each G may be the same or different. Further, m in the above formulas (1) and (2) is an integer of 0 to 4, preferably 0, 3 or 4, more preferably 0 or 4. At this time, the bonding position of G to the benzene ring is appropriately selected depending on the reactivity between the compound (A) and fluorine. For example, when m is 2, the position of (2,5) It is preferred that The numbering for specifying the position used above is given according to the numbering in the above equation (1). Further, k in the above formulas (1) and (2) is an integer of 0 to 4, preferably 0 or 1, and more preferably 0.

From this, the compound (A) particularly preferably used in the present invention is a compound represented by the following formula.

[0017]

Embedded image The compound (A) used in the present invention is not particularly limited as long as it is a compound represented by the above formula (1). For example, when k and m are 0 in the above formula (1), terephthalaldehyde And a compound (B ₁ ) represented by the following formula (3) and a compound (B ₂ ) represented by the following formula (4)
Are reacted by a known method. More specifically, compound (A) is obtained by dissolving terephthalaldehyde in an organic solvent such as toluene, and adding compound (B ₁ )
After the addition of the compound (B ₂ ) and the reaction, the mixture can be efficiently prepared by performing the reaction while removing water by further heating. In the above reaction, it is preferable to carry out the reaction in the presence of an acid catalyst in order to improve the yield. Examples of the acid catalyst used in this case include inorganic acids such as hydrochloric acid, sulfuric acid, and nitric acid; and organic acids such as oxalic acid, acetic acid, paratoluenesulfonic acid, benzenesulfonic acid, and trifluoroboron ether complex. Of these, paratoluenesulfonic acid and trifluoroboron ether complex are preferred because of their excellent solubility.

[0018]

Embedded image

[0019]

Embedded image In the above formulas (3) and (4), X _{1 to} X ₄ , Y ₁ and Y ₂ are the same as defined in the above formula (1).

Compound (B ₁ ) used in the present invention
And the compound (B ₂ ) may be the same or different as long as they are compounds represented by the formulas (3) and (4), respectively. Specifically, the compounds represented by formulas (3) and (4) include 1,2-ethanedithiol, 1,3-propanedithiol, ethylene glycol, 1,3-propanediol, and 2-mercaptoethanol. Among them, 1,2-ethanedithiol and 1,3-propanedithiol are preferably used.

Hereinafter, specific examples of the compound (A) according to the present invention will be illustrated below when k and m are 0 in the formula (1):

[0022]

Embedded image Among the above compounds, a compound represented by the following formula is preferably used as the compound (A) according to the present invention.

[0023]

Embedded imageAlso, as used herein, "fluorine"
If a fluorine molecule (F _Two), Fluorine compound, fluorine ion
Which include fluorine compounds and
Fluorine ions are preferably used as fluorine according to the present invention
Is done.

In the present invention, when a fluorine compound is used as fluorine, the fluorine compound is not particularly limited, but preferred examples of the fluorine compound include pyridine hydrogen fluoride, ammonium hydrogen fluoride, and fluorine fluoride. Potassium hydride, hydrofluoric acid, sodium hydrogen fluoride, ammonium fluoride, antimony fluoride (I
II), antimony (V) fluoride, and cesium fluoride. Of these, hydrogen fluoride pyridine, cesium fluoride, and hydrofluoric acid are preferably used.

In the present invention, when fluorine ions are used as fluorine, the source of fluorine ions is not particularly limited, and is preferably supplied from the above fluorine compound.

In the present invention, the amount of fluorine is not particularly limited and is appropriately selected in consideration of the reaction yield and the production cost, but the introduction of fluorine atoms into the compound (A) proceeds efficiently. In order to improve the yield of the desired product, the fluorine is preferably present in an excessive concentration with respect to the compound (A). Specifically, the amount of fluorine is 4 mol or more, more preferably 4 to 100 mol, and still more preferably 4 to 4 mol per 1 mol of compound (A).
It is preferably 0 mol, most preferably 4 to 20 mol. In this case, if the amount of fluorine is less than 4 mol, fluorine is not completely introduced into the compound (A), and the yield of the target product is undesirably reduced. On the other hand, even if fluorine is added in excess of 100 moles, the yield does not change and it is economically disadvantageous, and the treatment of residual fluorine is also undesirably expensive.

In the present invention, the compound (A) and the fluorine may be charged in a batch or sequentially. However, considering the yield, the compound (A) is the last. It is preferable to charge the liquid.

In the present invention, the reaction temperature of the compound (A) with fluorine is set to a value in order to prevent the need for special equipment due to the reaction at a high temperature and to prevent the yield from deteriorating due to decomposition of the reaction reagent. The temperature is preferably from 100C to less than 80C, more preferably from -80C to 30C, and most preferably from -20C to 25C. The control of the reaction temperature is performed by a known method. For example, the reaction solution is immersed in a refrigerant at a desired temperature, or an inert gas (for example, nitrogen, argon or helium, etc.) cooled by liquid nitrogen or the like is used. ) Into the reaction vessel or bubbling through the reaction solution. The reaction time depends on the type of compound (A) or fluorine,
Although it depends on the reaction conditions and the like, it is usually 1 to 24 hours, preferably 2 to 12 hours.

In the present invention, the reaction between compound (A) and fluorine may be carried out without solvent, in the presence of an inorganic solvent or in the presence of an organic solvent, but the compound (A) and fluorine are dissolved. As a result, the reaction efficiency is improved and the heat removal is facilitated. Therefore, the reaction is preferably performed in the presence of an organic solvent.

In the above embodiment, the reaction between the compound (A) and fluorine in the presence of an organic solvent is carried out by adding the compound (A) to an organic solvent containing fluorine, preferably gradually. Is done. As used herein, the term "organic solvent containing fluorine" means a state in which fluorine is uniformly dissolved or dispersed in an organic solvent. The organic solvent containing fluorine is specifically obtained using a known technique such as adding the above-mentioned fluorine compound to the organic solvent shown below.
At this time, the final concentration of the compound (A) in the organic solvent is:
Considering the reaction yield and production cost, 1 to 40% by weight,
Preferably it is 3 to 30% by weight.

Alternatively, in the above embodiment, the reaction of compound (A) with fluorine in the presence of an organic solvent is carried out by reacting compound (A)
The compound (A) may be reacted with fluorine by blowing fluorine such as hydrogen fluoride gas into an organic solvent containing. At this time, the concentration of the compound (A) in the organic solvent is 1 to 40% by weight, preferably 3 to 30% by weight in consideration of the reaction yield and the production cost. Any amount may be introduced as long as it is introduced in such an amount, but it is usually 5 to 200 ml / min, preferably 10 to 100 ml / min.

The organic solvent used in the present invention is not particularly limited as long as it is a solvent that is not fluorinated. For example, pentane, hexane, cyclohexane,
Aliphatic or aromatic hydrocarbons such as octane and xylene, dichloromethane, 1,2-dichloroethane, chloroform, 1,1,2,2-tetrachloroethane, carbon tetrachloride, halogen-containing fats such as trichlorofluoromethane and chlorotoluene And aromatic or aromatic hydrocarbons, diglyme, and tetrahydrofuran. Among these, dichloromethane, chloroform, and 1,2-dichloroethane are preferably used in consideration of efficiently proceeding the reaction and improving the yield. The organic solvent used in the present invention is LiAlH
₄ , It is preferably used as a solvent dried with a known desiccant such as CaH ₂ or molecular sieve.

In the present invention, the reaction between the compound (A) and fluorine is carried out when the water content of the gas phase of the reaction system is 10%.
0 volppm or less, more preferably 50 volppm
Hereafter, it is most preferable to carry out in an atmosphere of 10 vol ppm or less. At this time, the water content is 100
If the content exceeds vol ppm, disadvantages such as a reduction in the efficiency of fluorine atom introduction and a corrosion of the reaction vessel occur. Therefore, before charging a solvent containing fluorine into the reaction vessel, an inert gas such as argon, helium or nitrogen is added so that the water content becomes 100 vol ppm or less, for example,
It is preferable to replace the inside of the reaction vessel in the form of a dry gas passed through liquid nitrogen and dried.

Further, in the present invention, in order to improve the reaction efficiency, the reaction of the compound (A) with fluorine is preferably carried out in the presence of a bromine-containing compound.

In the above embodiment, the bromine-containing compound is not particularly limited as long as it contains a bromine atom, but a compound having many bromine atoms per molecule is preferable. More preferably, it is a compound capable of generating Br ⁺ . Specifically, N-bromosuccinimide, 1,3-dibromo-5,5-dimethylhydantoin and the like are preferable. At this time, the amount of the bromine-containing compound is not particularly limited, but is usually 1 to 3 equivalents, preferably 1 to 1 equivalent to the compound (A).
It is twice equivalent. Here, the term “equivalent” means a value obtained by the following equation.

[0036]

(Equation 1) The reaction vessel used in the present invention is not particularly limited as long as it is not fluorinated, and examples thereof include a vessel coated with glass, polyethylene, polypropylene, a fluororesin, or a fluororesin. Of these coating materials, polyethylene, polypropylene, and fluorine resin are preferably used as coating materials in order to avoid contamination due to elution of alkali metal ions, heavy metal ions, and the like.

Next, after the reaction between the compound (A) and fluorine is completed in this manner, the reaction completed solution is separated and purified by a known means such as silica column chromatography or distillation or recrystallization. Thus, the desired product can be isolated.

At this time, in order to calculate the yield of the target product in the obtained reaction solution, the above-mentioned reaction completed solution is subjected to gas chromatography analysis equipped with a flame ionization detector. In this method, if the content is the same, a peak intensity proportional to the carbon number can be obtained. In addition, if the number of carbon atoms is the same, the peak intensity is proportional to the amount, so that quantitative analysis becomes possible.

[0039]

The present invention will now be described more specifically with reference to examples. The yield of the target product was calculated in the same manner as described in the embodiment of the present invention. Reference Example 1 In a glass 100 ml three-necked flask equipped with a stirrer, 6.65 g (50 mmo) of terephthalaldehyde was added.
l) and 50 g of dichloromethane. One more
After adding 10 ml (120 mmol) of 2-ethanedithiol and continuing stirring at 25 ° C. for 20 minutes, adding 10 ml (80 mmol) of boron trifluoride diethyl ether complex and continuing stirring at 25 ° C. for another 2 hours. As a result, a white precipitate was formed. The resulting white precipitate was filtered to obtain 10.8 g of 2,2 ′-(1,4-phenylene) bis-1,3-dithiolane (hereinafter referred to as “intermediate (1)”) (75% yield). ) Got. Reference Example 2 6.65 g (50 mmol) of terephthalaldehyde and toluene 5 were placed in a 100 ml three-neck glass flask equipped with a stirrer and a Dean-Stark trap.
0 g was charged. 3.4 g of ethylene glycol
(55 mmol) and 0.21 g of paratoluenesulfonic acid monohydrate (1 mmol in terms of paratoluenesulfonic acid)
l) was added and refluxed at 110 ° C. for 2 hours with stirring. The product is separated and purified by silica gel column chromatography, and 2,2 '-(1,4-phenylene)
Bis-1,3-dioxolane (hereinafter "intermediate (2)"
8.3 g (75% yield). Reference Example 3 4.0 g (30 mmol) of terephthalaldehyde was placed in a 100-ml three-neck glass flask equipped with a stirrer.
And 30 g of dichloromethane. Further 1,3-
After adding 8.1 g (75 mmol) of propanedithiol and stirring at 25 ° C. for 20 minutes, 6.3 ml (50 mmol) of boron trifluoride diethyl ether complex was added and stirring was continued at 25 ° C. for another 2 hours. After continuing,
A white precipitate formed. The resulting white precipitate was filtered to obtain 2,2 ′-(1,4-phenylene) bis-.
1,3-dithiane (hereinafter, referred to as “intermediate (3)”)
6.6 g (70% yield) were obtained. Reference Example 4 51.6 g (385 mmol) of terephthalaldehyde, 64.4 g (767 mmol) of ethanedithiol and 15 parts of toluene were placed in a 300-ml three-neck flask made of glass equipped with a stirrer and Dean-Stark Trap.
0 ml was charged. Further, 0.037 g (0.19 mmol) of paratoluenesulfonic acid monohydrate was added, and the mixture was refluxed at 110 ° C. for 3 hours with stirring, and the reaction was carried out while distilling off water generated during the reaction. The precipitated white solid was separated by filtration and dried to obtain 2,2′-
100 g of (1,4-phenylene) bis-1,3-dithiolane (hereinafter, referred to as “intermediate (4)”) (yield 91
%). Example 1 14.9 g (52 mmo) of 1,3-dibromo-5,5-dimethylhydantoin (hereinafter abbreviated as "DMH") was placed in a glass 2-liter three-necked flask equipped with a stirrer.
l) and 660 g of dichloromethane were charged and completely dissolved by stirring. The three-necked flask was immersed in ice water while flowing argon gas (water content of 1 vol ppm or less) into the three-necked flask. Hydrogen fluoride pyridine (HF-Pyridine: manufactured by Aldrich)
25 ml (1060 mmol) were added via syringe.
Intermediate (1) prepared in Reference Example 1 while stirring at 0 ° C.
7.7 g (27 mmol) were added in several portions. 2
After continuing stirring at 0 ° C. for 60 hours, dichloromethane 660 g
Was added.

After the reaction solvent was distilled off from this mixture, the mixture was passed through a basic alumina column. GC-M column effluent
As a result of S analysis, it was confirmed that 4-difluoromethylbenzaldehyde (product 1) and 1,4-bis (difluoromethyl) benzene (product 2) were formed. In a separate GC analysis, the area ratio of product 1 / product 2 was 10/90.

The reaction mixture obtained above was distilled under reduced pressure (5.
0 mmHg, 93-99 ° C) to obtain 3.8 g.
Of 1,4-bis (difluoromethyl) benzene was isolated (80% yield). Examples 2 to 4 The same operation as in Example 1 was carried out except that the addition temperature and reaction temperature of the intermediate (1) were changed to the temperatures shown in Table 1 below, and the 1,4-bis (difluoromethyl) produced ) The yield of benzene was measured. The results of Examples 1-4 are summarized in Table 1 below.

[0042]

[Table 1] From Table 1 above, when the addition temperature and the reaction temperature of the intermediate (1) are adjusted within the range of −20 to 25 ° C., the desired 1,4-bis (difluoromethyl) benzene can be obtained in a high yield. Is shown. Example 5 1.49 g (5.2 mmol) of DMH and 66 g of dichloromethane were charged into a 200-ml three-neck glass flask equipped with a stirrer, and completely dissolved by stirring. Argon gas (water content 1 volppm
Was flowed into a three-necked flask while immersing the three-necked flask in ice water. Hydrogen fluoride pyridine (Aldri
2.5 ml (106 mmol) was added with a syringe. While stirring at 0 ° C., 0.6 g (2.7 mmol) of the intermediate (2) prepared in Reference Example 2 was added in several portions. After stirring for 2 hours at 0 ° C., 66 g of dichloromethane were added.

After the reaction solvent was distilled off from this mixture, the mixture was passed through a basic alumina column. GC-M column effluent
As a result of S analysis, it was confirmed that 4-difluoromethylbenzaldehyde (product 1) and 1,4-bis (difluoromethyl) benzene (product 2) were formed. In a separate GC analysis, the area ratio of product 1 / product 2 was 30/70. Example 6 In Example 5, Reference Example 3 was used instead of Intermediate (2).
0.85 g (2.7 mmol) of intermediate (3) synthesized in
The operation was carried out in the same manner as in Example 5, except for using.

As a result of subjecting the obtained column effluent to GC-MS analysis, two kinds of 4-difluoromethylbenzaldehyde (product 1) and 1,4-bis (difluoromethyl) benzene (product 2) were formed. It was confirmed that it was done. In a separate GC analysis, the area ratio of product 1 / product 2 was 15/85. Example 7 1.49 g (5.2 mmol) of DMH and 66 g of dichloromethane were charged into a 200-ml three-neck glass flask equipped with a stirrer, and completely dissolved by stirring. While flowing argon gas into the three-necked flask, the three-necked flask was immersed in ice water, and 0.77 g (2.7 mmol) of the intermediate (1) prepared in Reference Example 1 was added in several portions. Furthermore, hydrogen fluoride pyridine (Ald
Rich) (2.5 ml, 106 mmol) was added in several portions with a syringe, and the mixture was further stirred at 0 ° C. for 2 hours, and then 66 g of dichloromethane was added.

After the reaction solvent was distilled off from this mixture, the mixture was passed through a basic alumina column. GC-M column effluent
As a result of S analysis, it was confirmed that 4-difluoromethylbenzaldehyde (product 1) and 1,4-bis (difluoromethyl) benzene (product 2) were formed. In a separate GC analysis, the area ratio of product 1 / product 2 was 60/40. Example 8 1.49 g (5.2 mmol) of DMH and 66 g of dichloromethane were charged into a 200-ml three-neck glass flask equipped with a stirrer, and completely dissolved by stirring. The three-necked flask was immersed in ice water while flowing argon gas into the three-necked flask. In addition, 0 ° C
(1) prepared in Reference Example (1) while stirring at
Was added in an amount of 0.6 g (2.1 mmol). 4.89 dm ³ (volume at 25 ° C., 0.2 mol in terms of HF) of hydrofluoric acid was gradually blown into this solution. After stirring for 2 hours at 0 ° C., 66 g of dichloromethane were added.

After the reaction solvent was distilled off from this mixture, the mixture was passed through a basic alumina column. GC-M column effluent
As a result of S analysis, it was confirmed that 4-difluoromethylbenzaldehyde (product 1) and 1,4-bis (difluoromethyl) benzene (product 2) were formed. In a separate GC analysis, the area ratio of product 1 / product 2 was 30/70. Example 9 Dichloromethane (DCM) and N-bromosuccinimide (NBS) were charged into a 200-ml three-neck glass flask equipped with a stirrer in the amounts shown in Table 2 below, and argon gas (water content: 1 vol ppm or less). Then, pyridine hydrogen fluoride (Aldrich; referred to as “HF-Pyr” in Table 1 below) was added in an amount shown in Table 1 below. The three-necked flask was placed in ice water, and 7.4 g (25.9 mmol) of the intermediate (4) synthesized in Reference Example 4 was added with stirring at an internal temperature of 0 to 5 ° C.
Stirring was continued at ice temperature for an additional 2 hours.

A 20% aqueous sodium hydroxide solution was added to the reaction mixture until the pH of the aqueous layer became 10 or more.
The precipitate formed during the neutralization process is filtered, and the organic layer of the filtrate is washed with dilute hydrochloric acid, and then distilled under reduced pressure (50 mmHg, 93 to 99
C.) to isolate 1,4-bis (difluoromethyl) benzene. Examples 10 to 19 The same operation as in Example 9 was performed, except that the amount was changed to the amount shown in the following table, to isolate 1,4-bis (difluoromethyl) benzene. In Examples 16 and 17, instead of N-bromosuccinimide (NBS), 1,3-dibromo-5,5-dimethylhydantoin (D
MH) was used as the bromine-containing compound, and in Examples 16 and 17, 1 was used instead of a 200 ml three-necked flask.
A liter three-necked flask was used. Example 1
In No. 9, no bromine containing compound was used.

The compositions and results of Examples 9 to 19 are shown in Table 2 below.

[0049]

[Table 2]

[0050]

As described above, the method of the present invention comprises reacting the compound (A) represented by the above formula (1) with fluorine to produce 1,4-bis (difluoro) represented by the above formula (2). (Alkyl) benzene derivatives. Therefore, according to the method of the present invention, the reaction between the compound (A) represented by the formula (1) and fluorine can be performed at low temperature and normal pressure, and a fluorine source is supplied at relatively low cost. And it is possible to produce the desired 1,4-bis (difluoroalkyl) benzene derivative represented by the formula (2) at low cost.

Continued on the front page (51) Int.Cl. ⁶ Identification code FI C07C 43/225 C07C 43/225 A

Claims (4)

[Claims] 1. The following formula (1): Provided that X ₁ , X ₂ , X ₃ and X ₄ are each independently
Represents an oxygen or sulfur atom; Y ₁ and Y ₂ each independently represent a group represented by —C _n H _2n —, wherein n
Is 2 or 3; k is an integer from 0 to 4; G represents a halogen group, an alkyl group, a perfluoroalkyl group or an alkoxy group; and m is an integer from 0 to 4;
Which comprises reacting a compound (A) represented by the formula with fluorine. A method for producing a 1,4-bis (difluoroalkyl) benzene derivative represented by the formula: 2. The method according to claim 1, wherein the reaction between the compound (A) and fluorine is carried out in the presence of an organic solvent. 3. The production method according to claim 1, wherein the reaction between the compound (A) and fluorine is performed in an atmosphere in which the water content of a gas phase portion of the reaction system is 100 vol ppm or less. 4. The method according to claim 1, wherein the reaction of the compound (A) with fluorine is carried out in the presence of a bromine-containing compound.