JP5476568B2 - Method for producing thiophene derivative - Google Patents

Description

  The present invention relates to a method for producing a thiophene derivative.

Aromatic monomers represented by pyrrole derivatives, aniline derivatives, thiophene derivatives and the like have been used for the production of conductive polymers, and various studies have been conducted for practical use. In particular, a polymer using a thiophene derivative as a raw material has high transparency in addition to high conductivity, so that the thiophene derivative is an important aromatic monomer.
Among thiophene derivatives, 3,4-ethylenedioxythiophene has been put into practical use as a raw material for solid electrolytic capacitors, conductivity imparting agents and the like.
As a method for producing this 3,4-ethylenedioxythiophene, a production method is known in which 3,4-dimethoxythiophene is heated to reflux in toluene together with ethylene glycol in the presence of p-toluenesulfonic acid (Non-Patent Document). 1).

  On the other hand, 3,4-dimethoxythiophene is also known to be obtained by a production method in which 3,4-dibromothiophene is reacted with metallic sodium in the presence of potassium iodide and copper oxide in a methanol solution (non-patent document). Reference 2).

However, since the purity of 3,4-ethylenedioxythiophene obtained by these production methods is not sufficient, when a polymer is produced using this 3,4-ethylenedioxythiophene as a raw material, the conductivity of the obtained polymer is not There was a problem that performance such as property was not sufficient.
As an improvement measure, there is a method of purifying the obtained 3,4-ethylenedioxythiophene. However, there is a problem that the yield of the finally obtained high purity 3,4-ethylenedioxythiophene is lowered. there were.
Synthetic Communications, 28 (12), 2237-2244 (1998) Tetrahedron Letters, 45, 6049-6050 (2004)

  An object of the present invention is to provide a production method that gives a high-purity thiophene derivative, and in particular, to provide a production method that gives a high-purity thiophene derivative in a high yield.

  As a result of intensive studies by the inventors to solve the above problems, the following production comprising the step of reacting a halogenated thiophene and an alkali metal alkoxide in an alcohol solvent and the step of distilling the alcohol solvent out of the system It has been found that the method is suitable for the purposes of the present invention and the present invention has been completed.

That is, the present invention
[1] General formula (1)

(X in the formulas are independent of each other and may be the same as or different from each other and each represents a fluorine atom, a chlorine atom, a bromine atom or an iodine atom.)
A step of reacting a halogenated thiophene represented by the formula (1) with an alkali metal alkoxide in an alcohol solvent, the method including an operation of distilling the alcohol solvent out of the reaction system,
General formula (2)

(In the formula, R ₁ and R ₂ are each independently the same or different and each represents a chain or branched alkyl group having 1 to 20 carbon atoms or an aryl group.)
Obtaining a dialkoxythiophene represented by:
Dialkoxythiophene represented by the general formula (2) and the general formula (3)

(In the formula, each Z independently represents an oxygen atom or a sulfur atom, and R represents a linear or branched alkylene group having 1 to 20 carbon atoms or an arylene group having 1 to 20 carbon atoms. )
And a compound represented by
General formula (4)

(In the formula, R ₁ and R ₂ are each independently the same or different and each represents a chain or branched alkyl group having 1 to 20 carbon atoms or an aryl group.)
A step of reacting while distilling out the compound represented by
Including,
General formula (5)

(In the formula, each Z independently represents an oxygen atom or a sulfur atom, and R represents a linear or branched alkylene group having 1 to 20 carbon atoms or an arylene group having 1 to 20 carbon atoms. )
The manufacturing method of the thiophene derivative represented by these is provided.

The present invention also provides
[2] The step of obtaining a dialkoxythiophene represented by the general formula (2)
(A) an operation of mixing a halogenated thiophene represented by the general formula (1) and an alkali metal alkoxide in an alcohol solvent, and then distilling the alcohol solvent out of the reaction system;
(B) an operation of mixing the halogenated thiophene represented by the general formula (1) and the alkali metal alkoxide in the alcohol solvent while distilling the alcohol solvent out of the reaction system, and (c) the alkali metal alkoxide. An operation of mixing the halogenated thiophene represented by the general formula (1) and the alkali metal alkoxide in the alcohol solution after distilling off the alcohol solvent from the alcohol solution of
The method for producing a thiophene derivative according to the above [1], comprising at least one selected from the group consisting of:

The present invention also provides
[3] The step of obtaining the dialkoxythiophene represented by the general formula (2) is based on the total amount of the alkali metal alkoxide before the reaction in the presence of the copper catalyst, and the concentration of the alkali metal alkoxide with respect to the alcohol solvent. The method for producing a thiophene derivative according to the above [1] or [2] is carried out in a range of 15 wt% to 55 wt%.

The present invention also provides
[4] The step of obtaining the dialkoxythiophene represented by the general formula (2) is based on the total amount of the alkali metal alkoxide before the reaction, and the concentration of the alkali metal alkoxide with respect to the alcohol solvent is 15% by weight to 50% by weight. The method for producing a thiophene derivative according to any one of the above [1] to [3], which comprises an operation of distilling off the alcohol solvent outside the reaction system while increasing the content within the range of%.

The present invention also provides
[5] In the step of obtaining the dialkoxythiophene represented by the general formula (2), the concentration of the alkali metal alkoxide with respect to the alcohol solvent is 30 based on the total amount of the alkali metal alkoxide before the reaction. The method for producing a thiophene derivative according to any one of the above [1] to [4], which is in the range of 50% by weight to 50% by weight.

The present invention also provides
[6] A step of reacting the dialkoxythiophene represented by the general formula (2) with the compound represented by the general formula (3),
General formula (6)

(Wherein R ₃ represents a linear or branched alkyl group having 1 to 6 carbon atoms),
General formula (7)

(Wherein R ₄ and R ₅ are each independently the same or different and each represents a linear or branched alkyl group having 1 to 6 carbon atoms) and a general formula (8)

(In the formula, R ₆ , R ₇ and R ₈ are each independently the same or different and each represents a chain or branched alkyl group having 1 to 6 carbon atoms.)
The method for producing a thiophene derivative according to any one of the above [1] to [5], which is carried out in the presence of an aromatic sulfonic acid represented by at least one selected from the group consisting of: .

The present invention also provides
[7] A step of reacting the dialkoxythiophene represented by the general formula (2) with the compound represented by the general formula (3),
A step of azeotroping the compound represented by the general formula (4) together with an aromatic organic solvent;
By cooling the azeotropic aromatic organic solvent and the compound represented by the general formula (4), a mixed liquid of the aromatic organic solvent and the compound represented by the general formula (4) is obtained. Process,
Contacting the mixture with water to remove the compound represented by the general formula (4);
The manufacturing method of the thiophene derivative in any one of said [1]-[6] containing is provided.

The present invention also provides
[8] A step of mixing a reaction solution of the dialkoxythiophene represented by the general formula (2) and the compound represented by the general formula (3) with glycols;
Separating and removing glycols from a mixture of the reaction solution and glycols;
The manufacturing method of the thiophene derivative in any one of said [1]-[7] containing is provided.

The present invention also provides
[9] A method for producing a thiophene derivative according to any one of the above [1] to [8], comprising a step of distilling the thiophene derivative represented by the general formula (5) in the presence of a polyol. To do.

The present invention also provides
[10] Halogen represented by the general formula (1) contained in the dialkoxythiophene represented by the general formula (2) obtained by the step of obtaining the dialkoxythiophene represented by the general formula (2) The method for producing a thiophene derivative according to any one of the above [1] to [9], wherein the content of thiophene is 0.05% or less.

The present invention also provides
[11] The above [1] to [1], wherein the content of dialkoxythiophene represented by the general formula (2) contained in the thiophene derivative represented by the general formula (5) is 0.05% or less. [10] A method for producing the thiophene derivative according to any one of [10].

The present invention also provides
[12] The method for producing a thiophene derivative according to any one of the above [1] to [11], wherein the thiophene derivative represented by the general formula (5) is 3,4-ethylenedioxythiophene. Is.

The present invention also provides
[13] General formula (1)

(X in the formulas are independent of each other and may be the same as or different from each other and each represents a fluorine atom, a chlorine atom, a bromine atom or an iodine atom.)
Wherein the halogenated thiophene and the alkali metal alkoxide represented by are reacted in an alcohol solvent,
An operation for distilling off the alcohol solvent out of the reaction system while increasing the concentration of the alkali metal alkoxide to the alcohol solvent within the range of 15 wt% to 50 wt% based on the total amount of the alkali metal alkoxide before the reaction. Including,
General formula (2)

(In the formula, R ₁ and R ₂ are each independently the same or different and each represents a chain or branched alkyl group having 1 to 20 carbon atoms or an aryl group.)
A method for producing a dialkoxythiophene represented by the formula:

  According to the production method of the present invention, since the dialkoxythiophene represented by the general formula (2) is obtained with high purity, impurities are mixed in the production of the thiophene derivative represented by the general formula (5). do not do. As a result, a high-purity thiophene derivative represented by the general formula (5) can be obtained in high yield, and in particular, a thiophene derivative having a purity of 99.5% or more by gas chromatography can be provided.

The production method of the present invention will be described in detail below.
First, the halogenated thiophene represented by the general formula (1) used in the production method of the present invention will be described.

General formula (1)

The halogenated thiophene represented by the formula is one in which halogen atoms are substituted at the 3-position and 4-position, and X in the formula is independent and may be the same or different from each other, and may be a fluorine atom, chlorine Either an atom, a bromine atom or an iodine atom.

  Specifically, for example, 3,4-difluorothiophene, 3,4-dichlorothiophene, 3,4-dibromothiophene, 3,4-diiodothiophene, 3-chloro-4-fluorothiophene, 3-bromo-4 -Fluorothiophene, 3-iodo-4-fluorothiophene, 3-bromo-4-chlorothiophene, 3-chloro-4-iodothiophene, 3-bromo-4-iodothiophene and the like.

  Among these, 3,4-difluorothiophene, 3,4-dichlorothiophene, 3,4-dibromothiophene, 3,4-diiodothiophene and the like are preferable in terms of price and handling, and 3,4-dibromothiophene is preferable. Further preferred.

  The said halogenated thiophene can use 1 type, or 2 or more types.

  The alkali metal alkoxide used in the present invention is, for example, a chain or branched chain hydroxyl group-containing aliphatic compound having 1 to 20 carbon atoms and an alkali metal, having 1 to 20 carbon atoms. Is obtained by reacting a hydroxyl group-containing aromatic compound or the like with an alkali metal, specifically, for example, a product obtained by reacting an aliphatic primary alcohol having 1 to 20 carbon atoms with an alkali metal, One obtained by reacting an aliphatic secondary alcohol having 1 to 20 carbon atoms and an alkali metal, one obtained by reacting an aliphatic tertiary alcohol having 1 to 20 carbon atoms and an alkali metal, Examples thereof include those obtained by reacting a hydroxyl group-containing benzene ring-containing compound having 1 to 20 carbon atoms with an alkali metal.

  More specifically, for example, lithium methoxide, lithium ethoxide, lithium propoxide, lithium butoxide, sodium methoxide, sodium ethoxide, sodium propoxide, sodium butoxide, potassium methoxide, potassium ethoxide, potassium propoxide, Examples include potassium butoxide, lithium phenoxide, sodium phenoxide, potassium phenoxide, and the like.

  Among these, sodium methoxide, sodium ethoxide, sodium propoxide, sodium butoxide and the like are preferable from the viewpoint of handleability, and sodium methoxide is more preferable.

  The said alkali metal alkoxide can use 1 type, or 2 or more types.

  Next, the step of reacting the halogenated thiophene represented by the general formula (1) with the alkali metal alkoxide will be described.

By reacting the halogenated thiophene represented by the general formula (1) with an alkali metal alkoxide in an alcohol solution,
General formula (2)

The dialkoxythiophene represented by can be obtained.

Here, R ₁ and R ₂ in the formula are independent of each other and may be the same as or different from each other, and represent a linear or branched alkyl group or aryl group having 1 to 20 carbon atoms. It is.

Specific examples of R ₁ and R ₂ include a methyl group, an ethyl group, a propyl group, a butyl group, and a phenyl group.
Among these, a methyl group, an ethyl group, a propyl group, a butyl group and the like are preferable in terms of reactivity and handling properties, and a methyl group is more preferable.

  Specific examples of the dialkoxythiophene represented by the general formula (2) include 3,4-dimethoxythiophene, 3-methoxy-4-ethoxythiophene, 3,4-diethoxythiophene, 3-methoxy- 4-propoxythiophene, 3-ethoxy-4-propoxythiophene, 3,4-dipropoxythiophene, 3-butoxy-4-methoxythiophene, 3-butoxy-4-ethoxythiophene, 3-butoxy-4-propoxythiophene, 3 , 4-dibutoxythiophene and the like.

  Next, examples of the alcohol solvent include methanol, ethanol, propanol, butanol, pentanol, hexanol, heptanol, octanol, methoxymethanol, methoxyethanol, methoxypropanol, methoxybutanol, ethylene glycol, propylene glycol and the like. it can.

  The alcohol is preferably methanol, ethanol, propanol, butanol or the like, and more preferably methanol.

  One or more alcohol solvents can be used.

  The step of reacting the halogenated thiophene represented by the general formula (1) with the alkali metal alkoxide in an alcohol solvent includes an operation of distilling the alcohol solvent out of the reaction system.

  The operation of distilling off the alcohol solvent to the outside of the reaction system is a method of heating the reaction system to a temperature not lower than the boiling point of the alcohol solvent, and heating the reaction system to a temperature not lower than the boiling point of the alcohol solvent under reduced pressure. It can be implemented by a method or the like.

  The operation of distilling off the alcohol solvent out of the reaction system may be carried out after mixing the halogenated thiophene represented by the general formula (1) and the alkali metal alkoxide in an alcohol solvent. The halogenated thiophene represented by the general formula (1) and the alkali metal alkoxide may be mixed in an alcohol solvent.

  In addition, the alkali metal alkoxide is dissolved or suspended in the alcohol solvent in a reaction vessel and the alcohol solvent is distilled out of the reaction system, and then expressed by the general formula (1). The halogenated thiophene and the alkali metal alkoxide may be mixed in an alcohol solvent.

  The operation of distilling off the alcohol solvent out of the reaction system is carried out after mixing the halogenated thiophene represented by the general formula (1) and the alkali metal alkoxide in an alcohol solvent, or the general formula The halogenated thiophene represented by (1) and the alkali metal alkoxide are preferably mixed in an alcohol solvent.

  Since the halogenated thiophene represented by the general formula (1) and the alkali metal alkoxide react rapidly by the operation of distilling the alcohol solvent out of the reaction system, the high purity general formula (2) The dialkoxythiophene represented by can be obtained.

  The reaction between the halogenated thiophene represented by the general formula (1) and the alkali metal alkoxide is carried out by mixing the halogenated thiophene represented by the general formula (1) and the alkali metal alkoxide. Specifically, the alcohol solvent and the alkali metal alkoxide are previously placed in a reaction vessel, and the halogenated thiophene represented by the general formula (1) is added continuously or intermittently. The alcohol-based solvent is put in a reaction vessel, and the alkali metal alkoxide and the halogenated thiophene represented by the general formula (1) are added to the reaction vessel continuously or intermittently. it can.

  The reaction temperature between the halogenated thiophene represented by the general formula (1) and the alkali metal alkoxide is preferably in the range of 40 to 200 ° C, more preferably in the range of 60 to 150 ° C.

  The reaction temperature is more preferably carried out at a temperature exceeding the boiling point of the alcohol solvent (a simple substance not containing a solute) under normal temperature and normal pressure, and specifically, the reaction temperature is most preferably in the range of 65 to 130 ° C.

  The reaction time of the halogenated thiophene represented by the general formula (1) and the alkali metal alkoxide is preferably in the range of 1 to 20 hours, more preferably in the range of 2 to 8 hours.

  The concentration of the alkali metal alkoxide used in the present invention with respect to the alcohol solvent is preferably in the range of 15 to 55% by weight, preferably in the range of 20 to 50% by weight, based on the total amount of the alkali metal alkoxide before the reaction. More preferred.

When the halogenated thiophene represented by the general formula (1) and the alkali metal alkoxide are mixed in an alcohol solvent, the alcohol of the alkali metal alkoxide is distilled while distilling the alcohol solvent out of the reaction system. The concentration with respect to the system solvent is preferably increased so as to increase in the range of 15% by weight to 50% by weight, based on the total amount of the alkali metal alkoxide before the reaction, It is preferable to increase the number.
For example, based on the total amount of the alkali metal alkoxide before the reaction, the concentration of the alkali metal alkoxide before the reaction with respect to the alcohol solvent is 30% by weight, and the concentration of the alkali metal alkoxide with respect to the alcohol solvent at the end of the reaction is 40% by weight. Then, it was carried out so that the concentration of the alkali metal alkoxide with respect to the alcohol solvent increased within the range of 15 wt% to 50 wt%.
In this way, while distilling out the alcohol solvent out of the reaction system, the concentration of the alkali metal alkoxide with respect to the alcohol solvent is increased to obtain the halogenated thiophene represented by the general formula (1) and the alkali metal alkoxide. By mixing in an alcohol solvent, dialkoxythiophene represented by the general formula (2) can be obtained with high purity and high yield.

  The method for increasing the concentration may be performed stepwise or continuously, for example.

  The concentration of the alkali metal alkoxide with respect to the alcohol solvent is more preferably in the range of 30 wt% to 50 wt% at the end of the reaction, based on the total amount of the alkali metal alkoxide before the reaction.

  The reaction end point means that the concentration of the halogenated thiophene represented by the general formula (1) by gas chromatography in the reaction mixture is the halogenated thiophene represented by the general formula (1) and the general formula ( The time when it becomes 0.05% or less with respect to the total of dialkoxythiophene represented by 2), preferably when it becomes less than 0.001%.

  In addition, when the halogenated thiophene represented by the general formula (1) and the alkali metal alkoxide are mixed in an alcohol solvent, a catalyst can be used.

  Examples of the catalyst include copper halides such as copper fluoride, copper chloride, copper bromide and copper iodide, and copper catalysts such as copper oxide.

  After completion of the reaction, for example, water is added and filtered, and then the crude product is extracted with an organic solvent, and the resulting organic solution layer is washed with water and dried.

  Examples of the organic solvent include aromatic organic solvents such as toluene and xylene.

  The organic solution of the crude product can be dried by, for example, an operation of heating and refluxing the organic solution of the crude product under reduced pressure to separate and remove azeotropic water.

  After the drying, the dialkoxythiophene represented by the general formula (2) can be obtained by distilling off the organic solvent.

  When the dialkoxythiophene represented by the general formula (2) is subjected to a distillation operation such as distillation under reduced pressure, the content of the halogenated thiophene represented by the general formula (1) by gas chromatography is 0.05. % Or less dialkoxythiophene represented by the general formula (2) can be obtained.

Next, dialkoxythiophene represented by the general formula (2) and the general formula (3)

  The step of reacting with the compound represented by the formula will be described.

  As the compound represented by the general formula (3) used in the present invention, for example, Z is each independently an oxygen atom or a sulfur atom, and R is a chain or branched chain having 1 carbon atom. And an alkylene group having ˜20 and an arylene group having 1 to 20 carbon atoms.

  Specifically, for example, ethylene glycol, propane-1,2-diol, butane-1,2-diol, pentane-1,2-diol, butane-2,3-diol, pentane-2,3-diol, Hexane-3,4-diol, propane-1,3-diol, butane-1,3-diol, pentane-1,3-diol, cyclohexane-1,2-diol, 1,2-dihydroxybenzene, 1,2 -Ethanedithiol, 1,3-propanedithiol and the like.

  The compound represented by the general formula (3) may be used alone or in combination of two or more. The same applies to the dialkoxythiophene represented by the general formula (2).

  The step of reacting the dialkoxythiophene represented by the general formula (2) and the compound represented by the general formula (3) is carried out in a solvent previously placed in a reaction vessel. It can be carried out by mixing the dialkoxythiophene represented by the formula (3) with the compound represented by the general formula (3).

  The mixing is represented by, for example, an operation in which a dialkoxythiophene represented by the general formula (2) and a compound represented by the general formula (3) are placed in the reaction vessel from the beginning, the general formula (3). The dialkoxythiophene represented by the general formula (2) can be intermittently or continuously dropped into a solution of the compound.

  Examples of the solvent include aromatic organic solvents such as toluene and xylene.

  When the dialkoxythiophene represented by the general formula (2) is reacted with the compound represented by the general formula (3), it is preferable to use an acid catalyst.

Examples of the acid catalyst include inorganic acids such as sulfuric acid, hydrochloric acid, and phosphoric acid,
Alkyl-substituted organic sulfonic acids such as methanesulfonic acid and dodecylsulfonic acid,
Halogenated alkyl-substituted organic sulfonic acids such as trifluoromethanesulfonic acid, trifluoroethanesulfonic acid, trifluoromethanesulfonylimide acid, trifluoromethanesulfonylmethide acid,
Cyclic sulfonic acids such as camphorsulfonic acid,
Alkyl-substituted benzenesulfonic acid such as benzenesulfonic acid, p-toluenesulfonic acid, ethylbenzenesulfonic acid, isopropylbenzenesulfonic acid, naphthalenesulfonic acid, alkyl-substituted naphthalenesulfonic acid, anthracenesulfonic acid, alkyl-substituted anthracenesulfonic acid, anthraquinonesulfonic acid, Substituted or unsubstituted such as exemplified by high molecular sulfonic acid such as alkyl-substituted or unsubstituted biphenyl sulfonic acid such as biphenyl sulfonic acid, alkyl biphenyl sulfonic acid, biphenyl disulfonic acid, polystyrene sulfonic acid, naphthalene sulfonic acid formalin condensate Aromatic sulfonic acid is mentioned.

As the aromatic sulfonic acid, specifically,
General formula (6)

(Wherein R ₃ represents a linear or branched alkyl group having 1 to 6 carbon atoms),
General formula (7)

(Wherein R ₄ and R ₅ are each independently the same or different and each represents a linear or branched alkyl group having 1 to 6 carbon atoms),
General formula (8)

(In the formula, R ₆ , R ₇ and R ₈ are each independently the same or different and each represents a chain or branched alkyl group having 1 to 6 carbon atoms.) Etc. are preferred.

  When at least one of the general formulas (6), (7), and (8) is used as the aromatic sulfonic acid, it is represented by the dialkoxythiophene represented by the general formula (2) and the general formula (3). It is possible to suppress the formation of a polymer or the like generated when the compound is reacted with the compound to be obtained, and the thiophene derivative represented by the general formula (5) is obtained in a high yield.

Specific examples of the aromatic sulfonic acid represented by the general formula (6) include, for example, toluenesulfonic acid, ethylbenzenesulfonic acid, propylbenzenesulfonic acid, butylbenzenesulfonic acid, pentylbenzenesulfonic acid, hexylbenzenesulfonic acid, And cyclohexylbenzenesulfonic acid (including various isomers).
The aromatic sulfonic acid represented by the general formula (6) preferably has R ₃ having 2 to 6 carbon atoms, specifically, ethylbenzene sulfonic acid, propyl benzene sulfonic acid, butyl benzene sulfonic acid, pentyl benzene. Sulfonic acid, hexylbenzenesulfonic acid, cyclohexylbenzenesulfonic acid and the like (including various isomers) are preferable.

  Specific examples of the aromatic sulfonic acid represented by the general formula (7) include, for example, dimethylbenzenesulfonic acid, ethylmethylbenzenesulfonic acid, diethylbenzenesulfonic acid, methylpropylbenzenesulfonic acid, ethylpropylbenzenesulfonic acid, Dipropylbenzenesulfonic acid, butylmethylbenzenesulfonic acid, butylethylbenzenesulfonic acid, butylpropylbenzenesulfonic acid, dibutylbenzenesulfonic acid, methylpentylbenzenesulfonic acid, ethylpentylbenzenesulfonic acid, pentylpropylbenzenesulfonic acid, butylpentylbenzenesulfone Acid, dipentylbenzenesulfonic acid, hexylmethylbenzenesulfonic acid, ethylhexylbenzenesulfonic acid, hexylpropylbenzenesulfonic acid, butyl Xylbenzenesulfonic acid, hexylpentylbenzenesulfonic acid, dihexylbenzenesulfonic acid, cyclohexylmethylbenzenesulfonic acid, cyclohexylethylbenzenesulfonic acid, cyclohexylpropylbenzenesulfonic acid, cyclohexylbutylbenzenesulfonic acid, cyclohexylpentylbenzenesulfonic acid, cyclohexylhexylbenzenesulfonic acid And dicyclohexylbenzenesulfonic acid (including various isomers).

  Specific examples of the aromatic sulfonic acid represented by the general formula (8) include, for example, trimethylbenzenesulfonic acid, triethylbenzenesulfonic acid, tripropylbenzenesulfonic acid, tributylbenzenesulfonic acid, tripentylbenzenesulfonic acid, Trihexylbenzenesulfonic acid, tricyclohexylbenzenesulfonic acid, dimethylethylbenzenesulfonic acid, dimethylpropylbenzenesulfonic acid, dimethylbutylbenzenesulfonic acid, dimethylpentylbenzenesulfonic acid, dimethylhexylbenzenesulfonic acid, dimethylcyclohexylbenzenesulfonic acid, etc. Body).

  The aromatic sulfonic acid is preferably p-toluenesulfonic acid, xylenesulfonic acid, mesitylenesulfonic acid or cumenesulfonic acid, more preferably xylenesulfonic acid, mesitylenesulfonic acid or cumenesulfonic acid.

  As the aromatic sulfonic acid, a hydrate is preferably used.

  The acid catalyst can be used alone or in combination of two or more.

Next, when the dialkoxythiophene represented by the general formula (2) is reacted with the compound represented by the general formula (3), the general formula (4) generated as a by-product by the reaction.

Is carried out while distilling out the compound represented by the formula above.

Here, R ₁ and R ₂ are independent of each other and may be the same as or different from each other, and represent a linear or branched alkyl group or aryl group having 1 to 20 carbon atoms.

Examples of the compound represented by the general formula (4) include a linear or branched hydroxyl group-containing aliphatic compound having 1 to 20 carbon atoms, a hydroxyl group-containing aromatic compound having 1 to 20 carbon atoms, and the like. And
Specifically, for example, an aliphatic primary alcohol having 1 to 20 carbon atoms, an aliphatic secondary alcohol having 1 to 20 carbon atoms, an aliphatic tertiary alcohol having 1 to 20 carbon atoms, and 1 to 1 carbon atoms. Examples include 20 hydroxyl group-containing benzene ring-containing compounds.

  More specifically, examples include methanol, ethanol, propanol, butanol, pentanol, hexanol and the like.

When the compound represented by the general formula (4) is distilled out of the reaction system, for example, an aromatic organic solvent such as toluene and xylene and the compound represented by the general formula (4) are azeotroped. It is preferable to distill it out of the reaction system.
The aromatic organic solvent and the compound represented by the general formula (4) by cooling an azeotropic vapor mixture of the aromatic organic solvent and the compound represented by the general formula (4) outside the reaction system. And a mixed solution is obtained.
By washing this mixed solution with water, the compound represented by the general formula (4) can be removed.
Next, by returning the mixed liquid after washing into the reaction system, the compound represented by the general formula (4) can be efficiently distilled out of the reaction system.

From the dialkoxythiophene represented by the general formula (2) by distilling the compound represented by the general formula (4) generated by the ether exchange reaction out of the reaction system,
General formula (5)

The conversion rate to the thiophene derivative represented by is improved. Thereby, the thiophene derivative represented by the general formula (5) can be obtained with high purity and high yield.

  Z is independently an oxygen atom or a sulfur atom, and R represents a linear or branched alkylene group having 1 to 20 carbon atoms and an arylene group having 1 to 20 carbon atoms. .

  The reaction temperature of the dialkoxythiophene represented by the general formula (2) and the compound represented by the general formula (3) in the present invention is preferably in the range of 40 to 200 ° C, and in the range of 80 to 150 ° C. More preferably.

  In addition, the reaction time between the dialkoxythiophene represented by the general formula (2) and the compound represented by the general formula (3) is preferably in the range of 1 to 20 hours, and is in the range of 2 to 8 hours. More preferred.

  After completion of the reaction, for example, water is added to the reaction solution, and filtration is performed.

Insoluble components that do not dissolve in the reaction solution may occur in the reaction solution. In this case, the insoluble component can be dissolved in glycols by adding glycols to the reaction solution. Since the glycols are separated from the reaction solution, the insoluble components can be removed from the reaction solution by separating and removing the glycols in which the insoluble component is dissolved.
Further, since the glycols are dissolved in water, the glycols can be removed from the reaction solution by washing the reaction solution with water.

Examples of the glycols include ethylene glycol, diethylene glycol, propylene glycol, and dipropylene glycol.
The glycols are preferably ethylene glycol and propylene glycol, and more preferably ethylene glycol.

Next, the reaction solution after washing with water is dried.
As a method for drying the reaction solution after washing with water, for example, the reaction solution after washing with water can be heated to reflux under reduced pressure to separate and remove azeotropic water.

  After the drying, the thiophene derivative represented by the general formula (5) can be obtained by distilling off the solvent.

The thiophene derivative represented by the general formula (5) can be purified by distilling the thiophene derivative represented by the general formula (5).
In the distillation operation, the thiophene derivative represented by the general formula (5) is preferably distilled from a mixed solution of the thiophene derivative represented by the general formula (5) and a polyol.
By using the polyols during the distillation operation, it is possible to prevent the distillation residue from solidifying inside the reaction vessel.

Examples of the polyols include polyethylene glycol and polypropylene glycol.
The polyols preferably have a number average molecular weight in the range of 200 to 1,000, and more preferably in the range of 300 to 600.

  The polyol to be used is preferably in the range of 1 to 100 parts by weight, more preferably in the range of 5 to 20 parts by weight with respect to 100 parts by weight of the thiophene derivative represented by the general formula (5).

  The polyols contained in the thiophene derivative represented by the general formula (5) after distillation can be removed by washing the thiophene derivative represented by the general formula (5) with water.

  The content of the dialkoxythiophene represented by the general formula (2) by gas chromatography is 0.05% by distillation operation such as distillation under reduced pressure of the thiophene derivative represented by the general formula (5). The following thiophene derivative represented by the general formula (5) can be obtained.

Examples of the thiophene derivative represented by the general formula (5) include the following.

  The thiophene derivative represented by the general formula (5) obtained by the present invention has a purity by gas chromatography of 99.5% or more, preferably 99.8% or more, and is widely applied as a raw material for high-performance polymers. can do.

  EXAMPLES Next, although an Example demonstrates this invention further in detail, this invention is not limited at all by these Examples.

[Production of 3,4-dimethoxythiophene from 3,4-dibromothiophene]
In a 100 ml four-necked flask, 21 g of sodium methoxide and 72 g of methanol were placed (the concentration of sodium methoxide in the methanol solvent was 22.6% by weight based on the total amount of sodium methoxide before the reaction), and 70 ° C. under an argon atmosphere. And dissolved.

  After adding 0.83 g of cuprous bromide and dropping 15 g of 3,4-dibromothiophene, the reaction solution turned from colorless and transparent to black. After completion of the dropwise addition, 50 g of methanol was distilled off (the concentration of sodium methoxide in the methanol solvent was 48.8% by weight based on the total amount of sodium methoxide before the reaction), and the reaction was continued by heating to reflux at 97 ° C. did. When the reaction was monitored by gas chromatography, 3,4-dibromothiophene and 3-bromo-4-methoxythiophene were below the detection limit within 5 hours from the start of reflux.

  After adding water to the reaction mixture and filtering, the crude product was extracted with toluene, the toluene layer was washed with water, and the toluene layer was dried over magnesium sulfate.

  After removing magnesium sulfate by filtration, the toluene layer was concentrated with a rotary evaporator and then distilled under reduced pressure to obtain 7.28 g (yield 81.5%) of 3,4-dimethoxythiophene. The purity of this 3,4-dimethoxythiophene was 98.01% by gas chromatography.

  In addition, the purity (concentration) by the gas chromatography in this invention was displayed with the area ratio of the peak area obtained by the detection apparatus by FID, using Agilent Technologies 6890N network GC made from Agilent Technologies.

[Production of 3,4-dimethoxythiophene from 3,4-dibromothiophene]
In the case of Example 1, 33 g of methanol was distilled off after completion of the dropwise addition of 3,4-dibromothiophene (the concentration of sodium methoxide in the methanol solvent was 35.0% by weight based on the total amount of sodium methoxide before the reaction). ) And heated to reflux to continue the reaction. When the reaction was monitored by gas chromatography, 3,4-dibromothiophene and 3-bromo-4-methoxythiophene were below the detection limit within 5 hours from the start of reflux.

[Production of 3,4-dimethoxythiophene from 3,4-dibromothiophene]
In the case of Example 1, after completion of the dropwise addition of 3,4-dibromothiophene, 40.5 g of methanol was distilled off (the concentration of sodium methoxide in the methanol solvent was 40.0 based on the total amount of sodium methoxide before the reaction). (% By weight) and heated to reflux to continue the reaction. When the reaction was monitored by gas chromatography, 3,4-dibromothiophene and 3-bromo-4-methoxythiophene were below the detection limit within 2 hours from the start of reflux.

[Comparative Example 1]
[Production of 3,4-dimethoxythiophene from 3,4-dibromothiophene]
In a 200 ml four-necked flask, put 28.1 g of sodium methoxide and 97 g of methanol (concentration of sodium methoxide in methanol solvent is 22.5% by weight based on the total amount of sodium methoxide before the reaction) under an argon atmosphere. It was dissolved at 50 ° C.

  After adding 1.0 g of cuprous bromide and dropping 20 g of 3,4-dibromothiophene, the reaction solution turned from colorless and transparent to black. After completion of the dropwise addition, the reaction was continued by heating to reflux at 77 ° C. The reaction was continued for 13 hours, following the reaction by gas chromatography.

  After adding water to the reaction mixture and filtering, the crude product was extracted with toluene, the toluene layer was washed with water, and the toluene layer was dried over magnesium sulfate.

  After removing magnesium sulfate by filtration, the toluene layer was concentrated with a rotary evaporator and then distilled under reduced pressure to obtain 9.64 g (yield 81.0%) of 3,4-dimethoxythiophene. The purity of this 3,4-dimethoxythiophene was 61.42% by gas chromatography.

[Comparative Example 2]
[Production of 3,4-dimethoxythiophene from 3,4-dibromothiophene]
In the case of Comparative Example 1, the same as in Comparative Example 1, except that 72.3 g of methanol (the concentration of sodium methoxide in the methanol solvent was 28.0% by weight based on the total amount of sodium methoxide before the reaction) The operation was performed. The reaction was continued by heating under reflux, but at 9 hours from the start of reflux, gas chromatography of 3,4-dibromothiophene (DBrT) and 3-bromo-4-methoxythiophene (Br-MEOT) in the reaction solution The concentrations of were 0.20% and 3.29%, respectively.

[Production of 3,4-ethylenedioxythiophene from 3,4-dimethoxythiophene]
The following production was carried out using 3,4-dimethoxythiophene obtained by the same production method as in Example 2 above. The same applies to Examples 5 to 9 and Comparative Examples 3 to 9 described below.

  First, 10.4 g of 3,4-dimethoxythiophene, 6.74 g of ethylene glycol, 1.1 g of p-toluenesulfonic acid monohydrate and 76.6 g of toluene were placed in a 100 ml four-necked flask, and the mixture was heated and stirred under an argon atmosphere. .

  The mixture was heated to 100 ° C. while distilling off methanol at 95 ° C. At 100 ° C., the distillation of methanol was completed, and the reflux of toluene began.

  The composition change in the reaction solution was monitored by gas chromatography using N, N-dimethylformamide as an internal standard. As a result, 3,4-dimethoxythiophene became below the detection limit within 3 hours from the start of reflux. Table 1 summarizes the relationship between the time from the start of toluene reflux and the concentration of each component. EDOT, DMEOT, mono-substituted and di-substituted in Table 1 are substituted with ethylene glycol on one methoxy group of 3,4-ethylenedioxythiophene, 3,4-dimethoxythiophene and 3,4-dimethoxythiophene, respectively. And those in which both methoxy groups of 3,4-dimethoxythiophene are substituted with ethylene glycol.

  The conversion (%) in the table is the actual 3% in the reaction solution relative to the theoretical amount of 3,4-ethylenedioxythiophene when measured by gas chromatography using N, N-dimethylformamide as an internal standard. The ratio of the amount of 1,4-ethylenedioxythiophene is shown.

  Similarly, the residual ratio (%) indicates the ratio of the actual amount of 3,4-dimethoxythiophene in the reaction solution to the theoretical amount of 3,4-dimethoxythiophene.

  The reaction mixture was diluted with water, insolubles were removed by filtration, the crude product was extracted with toluene, the toluene layer was washed with water, washed with an aqueous sodium hydrogen carbonate solution, and dried over magnesium sulfate.

After removing magnesium sulfate by filtration, the toluene layer was concentrated by a rotary evaporator to obtain a crude product.
The yield of the crude product was 6.78 g (68.1%), and the purity was 98.69% by gas chromatography.

  The crude product was distilled under reduced pressure to obtain 4.65 g (yield 46.7%) of 3,4-ethylenedioxythiophene. The purity of 3,4-ethylenedioxythiophene was 99.64% by gas chromatography.

[Comparative Example 3]
[Production of 3,4-ethylenedioxythiophene from 3,4-dimethoxythiophene]
A 100 ml four-necked flask was charged with 2.01 g of 3,4-dimethoxythiophene, 1.34 g of ethylene glycol, 0.2 g of p-toluenesulfonic acid monohydrate and 11.83 g of toluene, and heated and stirred in an air atmosphere. Toluene was refluxed.

  When the reaction was monitored by gas chromatography, 3,4-dimethoxythiophene was 0.32% in 14 hours from the start of refluxing, so the reaction was terminated.

  The reaction mixture was diluted with water, insolubles were removed by filtration, the crude product was extracted with toluene, the toluene layer was washed with water, washed with an aqueous sodium hydrogen carbonate solution, and dried over magnesium sulfate.

  After removing magnesium sulfate by filtration, the toluene layer was concentrated by a rotary evaporator to obtain a crude product.

  The yield of the crude product was 1.28 g (64.7%), and the purity was 85.94% by gas chromatography.

  The crude product was distilled under reduced pressure to obtain 0.87 g (yield 44.0%) of 3,4-ethylenedioxythiophene. The purity of this 3,4-ethylenedioxythiophene was 96.28% by gas chromatography.

[Production of 3,4-ethylenedioxythiophene from 3,4-dimethoxythiophene]
Except that p-toluenesulfonic acid monohydrate of Example 4 was used and cumenesulfonic acid monohydrate having the same substance amount (number of moles) was used, the same operation as in Example 4 was performed, and the reaction solution was used. The change in the composition was monitored by gas chromatography using N, N-dimethylformamide as an internal standard. Table 2 summarizes the relationship between the time from the start of toluene reflux and the concentration of each component.

Distillation under reduced pressure was carried out using the crude product obtained by the same operation as in Example 4.
, 4-ethylenedioxythiophene 6.49g (yield 65.2%) was obtained. The purity of 3,4-ethylenedioxythiophene was 99.86% by gas chromatography.

[Production of 3,4-ethylenedioxythiophene from 3,4-dimethoxythiophene]
The same procedure as in Example 5 was performed, except that m-xylene-4-sulfonic acid monohydrate having the same substance amount (number of moles) was used instead of cumene sulfonic acid monohydrate in Example 5. The composition change in the reaction solution was monitored by gas chromatography using N, N-dimethylformamide as an internal standard. Table 3 summarizes the relationship between the time from the start of toluene reflux and the concentration of each component.

[Production of 3,4-ethylenedioxythiophene from 3,4-dimethoxythiophene]
The composition in the reaction solution was exactly the same as in Example 5, except that mesitylenesulfonic acid monohydrate having the same substance amount (in moles) was used instead of cumenesulfonic acid monohydrate in Example 5. The change was followed by gas chromatography using N, N-dimethylformamide as an internal standard. Table 4 summarizes the relationship between the time from the start of toluene reflux and the concentration of each component.

[Comparative Example 4]
[Production of 3,4-ethylenedioxythiophene from 3,4-dimethoxythiophene]
The same operation as in Example 5 was performed except that 2-naphthalenesulfonic acid monohydrate having the same substance amount (number of moles) was used instead of cumenesulfonic acid monohydrate in Example 5, and the reaction solution was The change in the composition was monitored by gas chromatography using N, N-dimethylformamide as an internal standard. Table 5 summarizes the relationship between the time from the start of reflux of toluene and the concentration of each component.

[Comparative Example 5]
[Production of 3,4-ethylenedioxythiophene from 3,4-dimethoxythiophene]
Except for using cumenesulfonic acid monohydrate of Example 5 and using dodecylbenzenesulfonic acid monohydrate of the same substance amount (in moles), the same operation as in Example 5 was performed, The composition change was monitored by gas chromatography using N, N-dimethylformamide as an internal standard. Table 6 summarizes the relationship between the time from the start of reflux of toluene and the concentration of each component.

  When dodecylbenzenesulfonic acid monohydrate is used, after the reaction is complete, dilute the reaction mixture with water, remove insolubles by filtration, extract the crude product with toluene, and wash the toluene layer with water. As a result, the toluene layer and the aqueous layer could not be separated.

[Comparative Example 6]
[Production of 3,4-ethylenedioxythiophene from 3,4-dimethoxythiophene]
The same operation as in Example 5 was performed except that (+)-10-camphorsulfonic acid monohydrate having the same substance amount (number of moles) was used instead of cumenesulfonic acid monohydrate of Example 5. The composition change in the reaction solution was monitored by gas chromatography using N, N-dimethylformamide as an internal standard. Table 7 summarizes the relationship between the time from the beginning of toluene reflux and the concentration of each component.

[Comparative Example 7]
[Production of 3,4-ethylenedioxythiophene from 3,4-dimethoxythiophene]
The same operation as in Example 5 was performed except that 2-amino-1-naphthalenesulfonic acid monohydrate having the same substance amount (number of moles) was used instead of cumenesulfonic acid monohydrate in Example 5. The composition change in the reaction solution was monitored by gas chromatography using N, N-dimethylformamide as an internal standard. Table 8 summarizes the relationship between the time from the beginning of toluene reflux and the concentration of each component.

[Comparative Example 8]
[Production of 3,4-ethylenedioxythiophene from 3,4-dimethoxythiophene]
Except that salicylic acid having the same substance amount (number of moles) was used instead of cumenesulfonic acid monohydrate of Example 5, the same operation as in Example 5 was performed, and the composition change in the reaction solution was changed to N, N- Dimethylformamide was followed by gas chromatography with internal standard. Table 9 summarizes the relationship between the time from the start of toluene reflux and the concentration of each component.

[Production of 3,4-ethylenedioxythiophene from 3,4-dimethoxythiophene]
In Example 4, a case where a 100 ml four-necked flask was used was described, but in Example 8, a case where a 300 L reaction vessel was used will be described. Operation procedures, quantity ratio relationships, and the like are the same as in the fourth embodiment.
FIG. 1 is a schematic view showing a reaction apparatus for reacting 3,4-dimethoxythiophene and ethylene glycol.

By reacting 3,4-dimethoxythiophene and ethylene glycol inside the 300 L reaction tank 1, 3,4-ethylenedioxythiophene is generated and methanol is by-produced. Methanol in the reaction solution 20 azeotropes with toluene, passes through the distillation column 2 and is cooled by the cooler 3 to become a mixed solution of methanol and toluene. The cooling tower 3 has a structure in which internal steam can be cooled by cooling water.
The mixed solution 40 of methanol and toluene is sent to the water washing tank 5 via the valve 10, the pipe 4 and the valve 11.

Water 30 is put in the washing tank 5, and the mixed solution 40 of methanol and toluene is sent to the upper layer of the washing tank 5 after contacting the water 30.
When the methanol / toluene mixed solution 40 comes into contact with the water 30, the methanol contained in the methanol / toluene mixed solution 40 is dissolved in the water 30.
The water-washed toluene solution 41 sent to the upper layer of the water washing tank 5 is sent to the cooling tower 3 via the pipes 7 and 8 by the liquid feed pump 6.

  The water-washed toluene solution 41 sent to the cooling tower 3 comes into contact with the mixed solution 40 of methanol and toluene. As a result, the concentration of methanol in the methanol / toluene mixture 40 returned to the 300 L reaction tank 1 decreases with time.

Thus, even when the reaction scale was expanded to 300 L by removing methanol outside the reaction system, the reaction time for obtaining 3,4-ethylenedioxythiophene from 3,4-dimethoxythiophene was within 5 hours. Can keep.
In addition, in the case of Example 8, although the case where the toluene solution 41 after water washing is circulated to the cooling tower 3 is shown, it replaces with the toluene solution 41 after water washing, and water 30 may be circulated to the cooling tower 3. it can. Even in this case, the reaction time required to obtain 3,4-ethylenedioxythiophene from 3,4-dimethoxythiophene can be kept within 5 hours.

[Production of 3,4-ethylenedioxythiophene from 3,4-dimethoxythiophene]
When the crude product of 3,4-ethylenedioxythiophene obtained in the case of Example 4 is distilled, polyethylene glycol having a number average molecular weight of 400 is added to the weight of 1/10 of the crude product to perform distillation. went.
There was no deposit in the 100 ml four-necked flask, and 93% by weight of 3,4-ethylenedioxythiophene was obtained based on the weight of the crude product.
Next, after 3,4-ethylenedioxythiophene was washed with water and 3,4-ethylenedioxythiophene was distilled again, the purity of this 3,4-ethylenedioxythiophene was 99.80% by gas chromatography. Met.

[Comparative Example 9]
[Production of 3,4-ethylenedioxythiophene from 3,4-dimethoxythiophene]
In the case of Example 9, when the crude product of 3,4-ethylenedioxythiophene was distilled using propylene carbonate instead of polyethylene glycol having a number average molecular weight of 400, 10% propylene carbonate was obtained by gas chromatography. It was confirmed that it was mixed to some extent.
Next, this 3,4-ethylenedioxythiophene was washed with water, and it was confirmed by gas chromatography that about 3% of propylene carbonate was mixed.
Similar results were obtained when ethylene carbonate and sulfolane were used instead of propylene carbonate.

  This application is based on application number Japanese Patent Application No. 2008-006448 filed in Japan on January 16, 2008, and the entire application is included in this application by reference. Part of it.

It is the schematic diagram showing the reactor which makes 3,4-dimethoxythiophene and ethylene glycol react.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 300L reaction tank 2 Distillation tower 3 Cooler 4,7,8,9 Piping 5 Water washing tank 6 Liquid feed pump 10,11 Valve 20 Reaction solution 30 Water 40 Mixture of methanol and toluene 41 Toluene solution after washing 50 Stirring blade

Claims (13)

General formula (1)
(X in the formulas are independent of each other and may be the same as or different from each other and each represents a fluorine atom, a chlorine atom, a bromine atom or an iodine atom.)
A step of reacting a halogenated thiophene represented by the formula (1) with an alkali metal alkoxide in an alcohol solvent, the method comprising an operation of distilling the alcohol solvent out of the reaction system,
General formula (2)
(In the formula, R ₁ and R ₂ are each independently the same or different and each represents a chain or branched alkyl group having 1 to 20 carbon atoms or an aryl group.)
Obtaining a dialkoxythiophene represented by:
Dialkoxythiophene represented by the general formula (2) and the general formula (3)
(In the formula, each Z independently represents an oxygen atom or a sulfur atom, and R represents a linear or branched alkylene group having 1 to 20 carbon atoms or an arylene group having 1 to 20 carbon atoms. )
And a compound represented by
General formula (4)
(In the formula, R ₁ and R ₂ are each independently the same or different and each represents a chain or branched alkyl group having 1 to 20 carbon atoms or an aryl group.)
A step of reacting while distilling out the compound represented by
Including,
General formula (5)
(In the formula, each Z independently represents an oxygen atom or a sulfur atom, and R represents a linear or branched alkylene group having 1 to 20 carbon atoms and an arylene group having 1 to 20 carbon atoms. )
A process for producing a thiophene derivative represented by
The said manufacturing method further including the process of distilling the thiophene derivative represented by the said General formula (5) in presence of polyols . The step of obtaining dialkoxythiophene represented by the general formula (2)
(A) an operation of mixing a halogenated thiophene represented by the general formula (1) and an alkali metal alkoxide in an alcohol solvent, and then distilling the alcohol solvent out of the reaction system;
(B) an operation of mixing the halogenated thiophene represented by the general formula (1) and the alkali metal alkoxide in the alcohol solvent while distilling the alcohol solvent out of the reaction system, and (c) the alkali metal alkoxide. An operation of distilling an alcohol solvent out of the alcohol solution out of the reaction system and then mixing the halogenated thiophene represented by the general formula (1) and the alkali metal alkoxide in the alcohol solution,
The method for producing a thiophene derivative according to claim 1, comprising at least one selected from the group consisting of:   In the step of obtaining dialkoxythiophene represented by the general formula (2), in the presence of a copper catalyst, the concentration of the alkali metal alkoxide with respect to the alcohol-based solvent is 15% based on the total amount of the alkali metal alkoxide before the reaction. The manufacturing method of the thiophene derivative of Claim 1 implemented by the range of% -55weight%.   The step of obtaining the dialkoxythiophene represented by the general formula (2) is based on the total amount of the alkali metal alkoxide before the reaction, and the concentration of the alkali metal alkoxide in the alcohol solvent is in the range of 15% by weight to 50% by weight. The manufacturing method of the thiophene derivative of Claim 1 including operation which distills an alcoholic solvent out of a reaction system, making it increase in the inside.   The step of obtaining the dialkoxythiophene represented by the general formula (2) is based on the total amount of the alkali metal alkoxide before the reaction, and the concentration of the alkali metal alkoxide with respect to the alcohol solvent is from 30% by weight at the end of the reaction. The method for producing a thiophene derivative according to claim 1, which is in the range of 50% by weight. The step of reacting the dialkoxythiophene represented by the general formula (2) with the compound represented by the general formula (3),
General formula (6)
(Wherein R ₃ represents a linear or branched alkyl group having 1 to 6 carbon atoms),
General formula (7)
(Wherein R ₄ and R ₅ are each independently the same or different and each represents a linear or branched alkyl group having 1 to 6 carbon atoms) and a general formula (8)
(In the formula, R ₆ , R ₇ and R ₈ are each independently the same or different and each represents a chain or branched alkyl group having 1 to 6 carbon atoms.)
The method for producing a thiophene derivative according to claim 1, which is carried out in the presence of an aromatic sulfonic acid represented by at least one selected from the group consisting of: The step of reacting the dialkoxythiophene represented by the general formula (2) with the compound represented by the general formula (3),
A step of azeotroping the compound represented by the general formula (4) together with an aromatic organic solvent;
By cooling the azeotropic aromatic organic solvent and the compound represented by the general formula (4), a mixed liquid of the aromatic organic solvent and the compound represented by the general formula (4) is obtained. Process,
Contacting the mixture with water to remove the compound represented by the general formula (4);
The manufacturing method of the thiophene derivative of Claim 1 containing this. Mixing a reaction solution of the dialkoxythiophene represented by the general formula (2) and the compound represented by the general formula (3) with glycols;
Separating and removing glycols from a mixture of the reaction solution and glycols;
The manufacturing method of the thiophene derivative of Claim 1 containing this. In the above step of distilling the thiophene derivative represented by the general formula (5) in the presence of polyols, 5 to 20 parts by weight with respect to 100 parts by weight of the thiophene derivative represented by the general formula (5). The method for producing a thiophene derivative according to any one of claims 1 to 8, wherein a polyol is used .   The halogenated thiophene represented by the general formula (1) contained in the dialkoxythiophene represented by the general formula (2) obtained by the step of obtaining the dialkoxythiophene represented by the general formula (2). The method for producing a thiophene derivative according to claim 1, wherein the content is 0.05% or less.   2. The thiophene derivative according to claim 1, wherein the content of the dialkoxythiophene represented by the general formula (2) contained in the thiophene derivative represented by the general formula (5) is 0.05% or less. Production method.   The method for producing a thiophene derivative according to claim 1, wherein the thiophene derivative represented by the general formula (5) is 3,4-ethylenedioxythiophene. 13. The reaction temperature according to claim 1, wherein the reaction temperature in the step of reacting the halogenated thiophene represented by the general formula (1) with the alkali metal alkoxide is in the range of 65 to 130 ° C. 13. A method for producing a thiophene derivative .