KR101558628B1

KR101558628B1 - Process for production of thiophene derivative

Info

Publication number: KR101558628B1
Application number: KR1020107017922A
Authority: KR
Inventors: 미네카주 코가; 마사키 니시야마; 요시히토 이시키타; 토시유키 키류; 요지 야마구치
Original assignee: 닛뽕 카릿또 가부시키가이샤
Priority date: 2008-01-16
Filing date: 2009-01-14
Publication date: 2015-10-07
Also published as: CN101910181A; KR20100113565A; WO2009090866A1; JPWO2009090866A1; JP5476568B2

Abstract

[PROBLEMS] To provide a method for producing a thiophene derivative of high purity at a high yield among methods for producing thiophene derivatives. [MEANS FOR SOLVING PROBLEMS] A step of reacting a thiophene halide and an alkali metal alkoxide in an alcohol-based solvent, the step of obtaining a dialkoxythiophene by a step including an operation of distilling an alcoholic solvent to the outside of the reaction system, Reacting a compound containing thiophene, an oxygen atom and the like with a by-product generated by the reaction while allowing it to migrate to the outside of the reaction system.

Description

TECHNICAL FIELD The present invention relates to a process for preparing a thiophene derivative,

The present invention relates to a process for preparing thiophene derivatives.

Aromatic ammonia typified by pyrrole derivatives, aniline derivatives, thiophene derivatives and the like is provided for the production of conductive polymers, and various studies have been conducted toward commercialization. In particular, thiophene derivatives are important aromatic monomers because they have high transparency as well as high conductivity.

Of the thiophene derivatives, 3,4-ethylenedioxythiophene has been put to practical use as a raw material for solid electrolytic capacitors, conductivity imparting agents and the like.

As a process for producing 3,4-ethylenedioxythiophene, 3,4-dimethoxythiophene is heated and refluxed in toluene together with ethylene glycol in the presence of p-toluenesulfonic acid (see Non-Patent Document One).

On the other hand, it is also known that 3,4-dioxythiophene is obtained by a method of reacting 3,4-dibromothiophene with metal sodium in the presence of potassium iodide and copper oxide in a methanol solution (Non-Patent Document 2).

However, since the purity of 3,4-ethylenedioxythiophene obtained by these production methods is not sufficient, when the polymer is produced using 3,4-ethylenedioxythiophene as a raw material, the resulting polymer has excellent performance such as conductivity There was a problem that it was not enough.

As a remedy for this, there is a method of purifying the obtained 3,4-ethylenedioxythiophene, but there is a problem that the yield of 3,4-ethylenedioxythiophene of high purity finally obtained is lowered.

Non-Patent Document 1: Synthetic Communications, 28 (12), 2237-2244 (1998) Non-Patent Document 2: Tetrahedron Letters, 45, 6049-6050 (2004)

It is an object of the present invention to provide a method for producing a high purity thiophene derivative, and in particular, to provide a method for producing a high purity thiophene derivative at a high yield.

In order to solve the above problems, the inventors of the present invention have made intensive investigations and have found that, in a step of reacting a thiophene halide with an alkali metal alkoxide in an alcoholic solvent, the step of distilling away the alcoholic solvent from the reaction system The following production method is suitable for the purpose of the present invention, and the present invention has been completed.

[1] A compound represented by the following general formula (1)

(Wherein X may be the same or different from each other and represents any one of a fluorine atom, a chlorine atom, a cancel atom and an oxo atom) and an alkali metal alkoxide in an alcohol-based solvent (2) by a process comprising an operation of distilling an alcoholic solvent to the outside of the reaction system,

(Wherein R ₁ and R ₂ may be the same or different and are each an alkyl group or an aryl group having 1 to 20 carbon atoms in the form of a straight or branched chain) to obtain a dialkoxythiophene,

The dialkoxythiophenes represented by the above general formula (2) and the dialkoxythiophenes represented by the following general formula (3)

(Wherein each 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 or an arylene group having 1 to 20 carbon atoms) Equation (4)

(Wherein R ₁ and R ₂ may be the same or different and are each an alkyl group or an aryl group having 1 to 20 carbon atoms in the chain or branched chain), while allowing the compound represented by the formula (5) < / RTI >

(Wherein Z is each independently an oxygen atom or a sulfur atom, and R represents an alkylene group having 1 to 20 carbon atoms in the chain or branched chain or an arylene group having 1 to 20 carbon atoms) Method.

Further, according to the present invention,

[2] A process for producing a dialkoxythiophene represented by the general formula (2)

(a) an operation in which an alkali metal alkoxide is mixed with the thiophene halide represented by the general formula (1) in an alcoholic solvent and then the alcoholic solvent is removed from the reaction system,

(b) an operation of mixing the thiophene halide represented by the general formula (1) and the alkali metal alkoxide in an alcoholic solvent while stirring the alcoholic solvent to the outside of the reaction system, and

(c) distilling the alcoholic solvent from the alcoholic solution of the alkali metal alkoxide to the outside of the reaction system, mixing the alkali metal alkoxide with the thiophene halide represented by the general formula (1) in the alcoholic solution,

Of the thiophene derivative according to [1], wherein the thiophene derivative is at least one selected from the group consisting of

Further, according to the present invention,

[3] The process for producing a dialkoxythiophene represented by the general formula (2), wherein the step of obtaining the dialkoxythiophene represented by the general formula (2) comprises, in the presence of the catalyst, the concentration of the alkali metal alkoxide in the alcoholic solvent Of the thiophene derivative according to the above [1] or [2], wherein the content of the thiophene derivative is 15% by weight to 55% by weight.

Further, according to the present invention,

[4] The process for producing a dialkoxythiophene represented by the above general formula (2), wherein the step of obtaining a dialkoxythiophene represented by the general formula (2) is carried out in such a manner that the concentration of the alkali metal alkoxide relative to the alcoholic solvent is 15 wt% 1] to [3] above, which comprises an operation of raising an alcoholic solvent to the outside of the reaction system while increasing the concentration of the thiophene derivative to within a range of 0.1 to 10%

Further, according to the present invention,

[5] The process for producing a dialkoxythiophene represented by the above general formula (2) is characterized in that the concentration of the alkali metal alkoxide in the alcoholic solvent, based on the total amount of the alkali metal alkoxide before the reaction, The present invention provides a method for producing the thiophene derivative according to any one of the above [1] to [4], wherein the concentration of the thiophene derivative is in the range of from 50% by weight to 50% by weight.

Further, according to the present invention,

[6] A process for reacting a dialkoxythiophene represented by the general formula (2) with a compound represented by the general formula (3)

(6)

(In the formula, R ₃ represents an alkyl group having 1 to 6 carbon atoms in the chain or branched chain), the following general formula (7)

(Wherein R ₄ and R ₅ may be the same or different from each other and represent a linear or branched alkyl group having 1 to 6 carbon atoms)

(Wherein R ₆ , R ₇ and R ₈ may be the same or different from each other and represent an alkyl group having 1 to 6 carbon atoms in the form of a straight or branched chain), an aromatic sulfonic acid represented by at least one group selected from the group consisting of The present invention provides a process for producing a thiophene derivative according to any one of the above [1] to [5], which is carried out in the presence of a base.

Also,

[7] A process for reacting a dialkoxythiophene represented by the general formula (2) with a compound represented by the general formula (3)

Azeotropically bringing the compound represented by the general formula (4) together with an aromatic organic solvent,

A step of obtaining a mixed solution of the aromatic organic solvent and the compound represented by the general formula (4) by cooling the entrained aromatic organic solvent and the compound represented by the general formula (4)

And a step of bringing the mixed liquid into contact with water to remove the compound represented by the general formula (4)

And a method for producing the thiophene derivative according to any one of the above [1] to [6].

Further, according to the present invention,

[8] a step of mixing the reaction solution of the dialkoxythiophene represented by the general formula (2) and the compound represented by the general formula (3) with glycols,

The present invention provides a process for producing a thiophene derivative according to any one of the above [1] to [7], which comprises a step of separating and removing glycols from a mixture of the reaction solution and glycols.

Further, according to the present invention,

[9] A process for producing a thiophene derivative according to any one of [1] to [8], which comprises a step of distilling a thiophene derivative represented by the above general formula (5) in the presence of a polyol .

Further, according to the present invention,

[10] A process for producing a dialkoxythiophene derivative represented by the above general formula (1), wherein the halogenated thiophene represented by the general formula (1) contained in the dialkoxythiophene represented by the general formula (2) To (9), wherein the content of the thiophene derivative is 0.05% or less.

Further, according to the present invention,

Any one of the above-mentioned [1] to [10], wherein the content of the dialkoxythiophene represented by the general formula (2) contained in the thiophene derivative represented by the general formula (5) And a method for producing the thiophene derivative.

Further, according to the present invention,

[12] A process for producing a thiophene derivative according to any one of [1] to [11], wherein the thiophene derivative represented by the general formula (5) is 3,4-ethylenedioxythiophene .

[13] A compound represented by the following general formula (1)

(In the formula, X may be the same or different from each other and represents any one of a fluorine atom, a chlorine atom, a cancel atom or an oxo atom) and an alkali metal alkoxide in an alcoholic solvent In the method,

Characterized in that it comprises the step of increasing the concentration of the alkali metal alkoxide relative to the alcoholic solvent to 15 to 50% by weight based on the total amount of the alkali metal alkoxide before the reaction, and distilling the alcoholic solvent out of the reaction system (2)

(Wherein R ₁ and R ₂ may be the same or different from each other and represent an alkyl group or an aryl group having 1 to 20 carbon atoms in the form of a straight or branched chain) will be.

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

1 is a schematic diagram showing a reaction apparatus for reacting 3,4-dimethoxythiophene with ethylene glycol.

Hereinafter, the production method of the present invention will be described in detail.

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

In general formula (1)

Is a halogen atom substituted at the 3-position or 4-position, and X in the above formula may be the same or different from each other and is any one of a fluorine atom, a chlorine atom, a cancel atom and an oxo atom.

Specifically, there may be mentioned, for example, 3,4-difluorothiophene, 3,4-dichlorothiophene, 3,4-dibromothiophene, 3,4-diiodothiophene, Bromo-4-chlorothiophene, 3-chloro-4-iodothiophene, 3-bromo-4-fluorothiophene, 3- - iodothiophene, and the like.

Of these, 3,4-difluorothiophene, 3,4-dichlorothiophene, 3,4-dibromothiophene, 3,4-diiodothiophene and the like are preferable from the viewpoint of price and handling, and 3,4 - < / RTI > dibromothiophene.

The thiophene halide may be used alone or in combination of two or more.

Examples of the alkali metal alkoxide used in the present invention include those obtained by reacting a linear or branched, hydroxyl group-containing aliphatic compound having 1 to 20 carbon atoms with an alkali metal, a hydroxyl group-containing aromatic compound having 1 to 20 carbon atoms, Specific examples thereof include those obtained by reacting an aliphatic primary alcohol having 1 to 20 carbon atoms with an alkali metal, those obtained by reacting an aliphatic secondary alcohol having 1 to 20 carbon atoms with an alkali metal, Those obtained by reacting an aliphatic tertiary alcohol having 1 to 20 carbon atoms with an alkali metal, and 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, there may be mentioned lithium methoxide, lithium ethoxide, lithium propoxide, lithium butoxide, sodium methoxide, sodium ethoxide, sodium propoxide, sodium butoxide, potassium methoxide, potassium Ethoxide, potassium propoxide, potassium butoxide, lithium phenoxide, sodium phenoxide, potassium phenoxide, and the like.

Of these, sodium methoxide, sodium ethoxide, sodium propoxide and sodium butoxide are preferable from the viewpoint of handling property, and sodium methoxide is more preferable.

The alkali metal alkoxide may be used alone or in combination of two or more.

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

By reacting the thiophene halide represented by the general formula (1) and the alkali metal alkoxide in an alcohol solution, the compound represented by the general formula (2)

Lt; / RTI > can be obtained.

Wherein R ₁ and R ₂ may be the same or different from each other and represent a straight or branched chain alkyl or aryl group having 1 to 20 carbon atoms.

R ₁ and R ₂ are specifically methyl, ethyl, propyl, butyl, phenyl and the like.

Among them, a methyl group, an ethyl group, a propyl group, a butyl group and the like are preferable in view of reactivity or handleability, and a methyl group is more preferable.

Specific examples of the dialkoxythiophenes represented by the general formula (2) include 3,4-dimethoxythiophene, 3-methoxy-4-ethoxythiophene, 3,4-diethoxythiophene, 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.

Examples of the alcohol solvent include methanol, ethanol, propanol, butanol, pentanol, hexanol, heptanol, octanol, methoxymethanol, methoxyethanol, methoxybutanol, methoxybutanol, ethylene glycol , Propylene glycol, and the like.

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

The alcoholic solvent may be used alone or in combination of two or more.

The step of reacting the alkali metal alkoxide with the thiophene halide represented by the general formula (1) in the alcohol-based solvent includes an operation in which the alcohol-based solvent is removed from the reaction system.

The operation of distilling the alcoholic solvent out of the reaction system can be carried out by a method of heating the reaction system to a temperature not lower than the boiling point of the alcoholic solvent, a method of heating the reaction system to a temperature not lower than the boiling point of the alcoholic solvent under reduced pressure,

In addition, the operation for lifting the alcohol-based solvent out of the reaction system may be carried out after mixing the thiophene halide represented by the general formula (1) and the alkali metal alkoxide in the alcohol-based solvent, And the alkali metal alkoxide may be mixed in an alcohol-based solvent.

The alkali metal alkoxide is dissolved or suspended in the alcohol-based solvent in the reactor, and the alcohol-based solvent is removed from the reaction system, and then the thiophene halide represented by the general formula (1) and the alkali metal The alkoxide may be mixed in an alcohol-based solvent.

The operation for lifting the alcoholic solvent out of the reaction system may be carried out after mixing the thiophene halide represented by the general formula (1) and the alkali metal alkoxide in an alcoholic solvent, or after the halogenated thiophene represented by the general formula (1) It is preferable to carry out the reaction while mixing the phenol and the alkali metal alkoxide in an alcohol-based solvent.

Since the halogenated thiophene represented by the general formula (1) reacts with the alkali metal alkoxide rapidly by the operation of causing the alcoholic solvent to flow out of the reaction system, the high-purity dialkoxy represented by the general formula (2) Thiophene can be obtained.

The reaction of the thiophene halide represented by the general formula (1) with the alkali metal alkoxide can be carried out by mixing the alkali metal alkoxide with the thiophene halide represented by the general formula (1), specifically, (1) by continuously or intermittently adding the alcohol-based solvent and the alkali metal alkoxide to the reaction vessel, placing the alcohol-based solvent in the reaction vessel, and then adding the alkali metal alkoxide And the thiophene halide represented by the general formula (1) continuously or intermittently to the reaction vessel.

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

It is more preferable that the reaction temperature is carried out at a temperature exceeding the boiling point of the alcoholic solvent (a solute-free one) under normal temperature and normal pressure. And most preferably in the range of 65 to 130 캜.

The reaction time of the thiophene halide 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 in the alcoholic solvent is preferably in the range of 15 to 50 wt%, more preferably in the range of 20 to 50 wt%, based on the total amount of the alkali metal alkoxide before the reaction.

When the thiophene halide represented by the general formula (1) and the alkali metal alkoxide are mixed in the alcohol-based solvent, the concentration of the alkali metal alkoxide in the alcohol-based solvent is increased before the reaction, while the alcohol- The amount of the alkali metal alkoxide is preferably increased to fall within a range of 15 to 50 wt% based on the total amount of the alkaline metal alkoxide, and is preferably increased to fall within a range of 20 to 50 wt%.

For example, the concentration of the alkali metal alkoxide before the reaction with respect to the alcoholic solvent before the reaction is 30% by weight 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 alcoholic solvent at the end of the reaction is 40% %, The concentration of the alkali metal alkoxide with respect to the alcoholic solvent is increased within the range of 15 wt% to 50 wt%.

By thus raising the concentration of the alkali metal alkoxide to the alcoholic solvent while distilling the alcoholic solvent out of the reaction system and mixing the alkali metal alkoxide with the thiophene halide represented by the general formula (1) in the alcoholic solvent, The dialkoxythiophenes represented by the above general formula (2) are obtained in high purity and high yield.

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

The concentration of the alkali metal alkoxide in the alcoholic solvent is more preferably 30% by weight to 50% by weight based on the total amount of the alkali metal alkoxide before the reaction.

The reaction completion time is a time point when the concentration of the thiophene halide represented by the general formula (1) by gas chromatography in the reaction mixture is higher than the concentration of the thiophene halide represented by the general formula (1) Is not more than 0.05% with respect to the total amount of the dialkoxythiophenes represented by the general formula (2), but is preferably less than 0.01%.

When the thiophene halide represented by the general formula (1) and the alkali metal alkoxide are mixed in an alcohol-based solvent, a catalyst can be used.

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

After completion of the reaction, for example, water or the like is added and filtrated, the crude product (crude product) is extracted with an organic solvent, the obtained organic solution layer is washed with water and dried.

As the organic solvent, for example, aromatic organic solvents such as toluene, xylene and the like can be exemplified.

The drying of the organic solution of the crude product can be carried out, for example, by heating and refluxing the organic solution of the crude product under reduced pressure, and separating and eliminating azeotropic water.

After the drying, the organic solvent is distilled off to obtain a dialkoxythiophene represented by the general formula (2).

When the content of the halogenated thiophene represented by the general formula (1) by gas chromatography is 0.05% or more, for example, by distillation operation such as distillation under reduced pressure, for example, the dialkoxythiophene represented by the general formula (2) Or less of the dialkoxythiophenes represented by the above general formula (2).

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

Is reacted with a compound represented by the following general formula (1).

Examples of the compound represented by the general formula (3) used in the present invention include compounds wherein Z is independently an oxygen atom or a sulfur atom, R is an alkylene group having 1 to 20 carbon atoms in the chain or branched chain, An arylene group having 1 to 20 carbon atoms, and the like.

Specific examples include ethylene glycol, propane-1,2-diol, butane-1,2-diol, pentane-1,2-diol, butane-2,3- 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 dialkoxythiophenes represented by the above general formula (2).

The step of reacting the dialkoxythiophene represented by the general formula (2) with the compound represented by the general formula (3) can be carried out by reacting a dialkoxythiophene represented by the general formula (2) Thiophene and the compound represented by the above general formula (3) may be mixed.

The mixing can be carried out, for example, from the beginning, by placing a dialkoxythiophene represented by the general formula (2) and a compound represented by the general formula (3) in a reaction vessel and operating the solution to a solution of the compound represented by the general formula (3) The dialkoxythiophene represented by the general formula (2) may be intermittently or continuously added dropwise.

As the solvent, for example, aromatic organic solvents such as toluene and xylene can be exemplified.

In the case of reacting the dialkoxythiophene represented by the general formula (2) 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, alkylsubstituted organic sulfonic acids such as methanesulfonic acid and dodecylsulfonic acid, trifluoromethanesulfonic acid, trifluoroethanesulfonic acid, trifluoromethanesulfonic acid, Halogenated alkyl-substituted organic sulfonic acids such as trifluoromethanesulfonyl imidic acid and the like, cyclic sulfonic acids such as camphorsulfonic acid, benzenesulfonic acid, p-toluenesulfonic acid, ethylbenzenesulfonic acid, isopropylbenzenesulfonic acid Alkyl-substituted benzenesulfonic acids such as benzenesulfonic acid, benzenesulfonic acid, benzenesulfonic acid and p-toluenesulfonic acid, naphthalenesulfonic acid, alkyl-substituted naphthalenesulfonic acid, anthracenesulfonic acid, alkyl- substituted anthracenesulfonic acid, anthraquinonesulfonic acid, biphenylsulfonic acid, Substituted or unsubstituted aromatic sulfonic acids exemplified by alkyl substituted or unsubstituted biphenyl sulfonic acid, polystyrenesulfonic acid, naphthalenesulfonic acid formalin condensate and other polymeric sulfonic acids, and the like.

Specific examples of the aromatic sulfonic acid include compounds represented by the general formula (6)

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

(7)

(Wherein R < ₄ > And R < ₅ > may be the same or different from each other and represent an alkyl group having 1 to 6 carbon atoms in the chain or branched chain,

(Wherein R < ₄ > And R < ₅ > may be the same or different from each other, and represent a straight or branched alkyl group having 1 to 6 carbon atoms.

When at least one of the above-mentioned general formulas (6), (7) and (8) is used as the aromatic sulfonic acid, the dialkoxythiophene represented by the general formula (2) and the compound represented by the general formula (3) The production of a polymer or the like which is produced in the reaction can be inhibited and a thiophene derivative represented by the above general formula (5) can be obtained in a high yield.

Specific examples of the aromatic sulfonic acid represented by the general formula (6) include, for example, aromatic sulfonic acids such as toluenesulfonic acid, ethylbenzenesulfonic acid, propylbenzenesulfonic acid, butylbenzenesulfonic acid, pentylbenzenesulfonic acid, hexylbenzenesulfonic acid, Sulfonic acid and the like (including various isomers).

The aromatic sulfonic acid represented by the general formula (6) preferably has 2 to 6 carbon atoms in R ₃ , and specific examples thereof include ethylbenzene sulfonic acid, propyl benzene sulfonic acid, butyl benzene sulfonic acid, pentyl benzene sulfonic acid, Sulfonic 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 dimethylbenzenesulfonic acid, ethylmethylbenzenesulfonic acid, diethylbenzenesulfonic acid, methylpropylbenzenesulfonic acid, ethylpropylbenzenesulfonic acid, dipropyl Benzenesulfonic acid, butylmethylbenzenesulfonic acid, butylethylbenzenesulfonic acid, butylpropylbenzenesulfonic acid, dibutylbenzenesulfonic acid, methylpentylbenzenesulfonic acid, ethylpentylbenzenesulfonic acid, pentylpropylbenzenesulfonic acid, butylpentylbenzenesulfonic acid, Hexyl benzene sulfonic acid, hexyl benzene sulfonic acid, hexyl propyl benzene sulfonic acid, butyl hexyl benzene sulfonic acid, hexyl pentyl benzene sulfonic acid, dihexyl benzene sulfonic acid, cyclohexyl methyl benzene sulfonic acid, , Cyclohexylbenzenesulfonic acid, cyclohexylpropylbenzenesulfonic acid, cyclohexylbutylbenzenesulfonic acid, cyclohexylpentylbenzenesulfonic acid, cyclohexylhexylbenzenesulfonic acid, dicyclohexylbenzenesulfonic acid and the like (including various isomers Can be listed.

Specific examples of the aromatic sulfonic acid represented by the general formula (8) include, for example, trimethylbenzenesulfonic acid, triethylbenzenesulfonic acid, tripropylbenzenesulfonic acid, tributylbenzenesulfonic acid, Dimethylhexyl benzene sulfonic acid, dimethyl cyclohexyl benzene sulfonic acid, dimethyl cyclohexyl benzene sulfonic acid, dimethyl cyclohexyl benzene sulfonic acid, dimethyl cyclohexyl benzene sulfonic acid, dimethyl cyclohexyl benzene sulfonic acid, etc. (Including various isomers).

The aromatic sulfonic acids are preferably p-toluenesulfonic acid, xylenesulfonic acid, mesitylenesulfonic acid, cumene sulfonic acid, and more preferably xylene sulfonic acid, mesitylenesulfonic acid, cumene sulfonic acid.

Further, an aromatic sulfonic acid hydrate is preferably used.

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

Next, in the case of reacting the dialkoxythiophene represented by the general formula (2) with the compound represented by the general formula (3), the compound represented by the general formula (4)

Is carried out while the compound represented by the formula (II) is removed from the reaction system.

Examples of the compound represented by the general formula (4) include linear or branched, hydroxyl group-containing aliphatic compounds having 1 to 20 carbon atoms, hydroxyl group-containing aliphatic compounds having 1 to 20 carbon atoms,

Specific examples thereof include aliphatic primary alcohols having 1 to 20 carbon atoms, aliphatic secondary alcohols having 1 to 20 carbon atoms, aliphatic tertiary alcohols having 1 to 20 carbon atoms, and hydroxyl group-containing benzene having 1 to 20 carbon atoms Ring-containing compounds, and the like.

More specifically, for example, methanol, ethanol, propanol, butanol, pentanol, hexanol and the like can be exemplified.

When the compound represented by the general formula (4) is distilled off from the reaction system, it is preferable that the aromatic organic solvent such as toluene, xylene and the compound represented by the general formula (4) are allowed to coexist and migrate out of the reaction system.

A mixed solution of the aromatic organic solvent and the compound represented by the general formula (4) is obtained by cooling the azeotropic mixed vapor of the aromatic organic solvent and the compound represented by the general formula (4) to the outside of the reaction system.

And the mixture solution thereof is washed with water, the compound represented by the general formula (4) can be removed.

Next, by returning the mixed solution after the washing to the reaction system, the compound represented by the general formula (4) can be efficiently removed from the reaction system.

(5) can be obtained from a dialkoxythiophene represented by the above general formula (2) by distilling the above-mentioned compound represented by the general formula (4)

The conversion rate to the thiophene derivative represented by the formula As a result, a thiophene derivative represented by the above general formula (5) can be obtained in high purity and in a high yield.

And 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 or 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 more preferably in the range of 80 to 150 ° C desirable.

The reaction time of 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, more preferably in the range of 2 to 8 hours.

After the reaction, for example, water or the like is added to the reaction solution and filtration is performed.

Insoluble components not dissolved in the reaction solution may be generated in the reaction solution. In this case, the insoluble component can be dissolved in the 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 components are dissolved.

Further, since the glycols dissolve 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, dipropylene glycol, and the like.

The glycols are preferably ethylene glycol or propylene glycol, and more preferably ethylene glycol.

Next, the reaction solution after washing is dried.

As the drying method of the reaction solution after the water washing, for example, the reaction solution after the washing with water can be heated and refluxed under reduced pressure to separate and remove the azeotropic water.

After the drying, the solvent is distilled off to obtain the thiophene derivative represented by the general formula (5).

The thiophene derivative represented by the general formula (5) can be purified by raising the thiophene derivative represented by the general formula (5).

In the case of the distillation operation, it is preferable to distill the thiophene derivative represented by the general formula (5) from a mixture of the thiophene derivative represented by the general formula (5) and the polyol.

In the case of such a distillation operation, by using the above-mentioned polyols, it is possible to prevent the distillation residue from solidifying in the reaction vessel.

Examples of the polyols include polyethylene glycol, polypropylene glycol, and the like.

The number average molecular weight of the polyols is preferably in the range of 200 to 1000, more preferably in the range of 300 to 600.

The polyol 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, based on 100 parts by weight of the thiophene derivative represented by the general formula (5).

The polyol 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).

When the content of the dihydrocithiophene represented by the general formula (2) by gas chromatography is 0.05% or less by the distillation operation such as the vacuum distillation, for example, of the thiophene derivative represented by the general formula (5) Or less, of the thiophene derivative represented by the above general formula (5) can be obtained.

Examples of the thiophene derivative represented by the above 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 not less than 99.5%, preferably not less than 99.8%, and can be widely applied as a raw material for a high-function polymer.

The present invention will be described in further detail with reference to the following examples, but the present invention is not limited in any way by these examples.

Example One

[Preparation of 3,4-dimethoxythiophene from 3,4-dibromothiophene]

21 g of sodium methoxide and 72 g of methanol were added to a 100 ml four-necked flask (the concentration of sodium methoxide relative to the methanol solvent was 22.6% by weight based on the total amount of sodium methoxide before the reaction) and dissolved at 70 占 폚 under an argon atmosphere.

After 0.83 g of cuprous bromide was added, and 15 g of 3,4-dibromothiophene was added dropwise, the reaction solution became colorless transparent to black. After completion of the dropwise addition, 50 g of methanol was distilled off (the concentration of sodium methoxide to the methanol solvent was 48.8% by weight based on the total amount of sodium methoxide before the reaction), and the reaction was continued under reflux at 97 占 폚. When the reaction was traced by gas chromatography, 3,4-dibromothiophene and 3-bromo-4-methoxythiophene were found to be below the detection limit at the reflux start time of 5 hours.

After water was added to the reaction mixture and the mixture was filtered, the crude product was extracted from toluene, and the toluene layer was washed with water, and then the toluene layer was dried with magnesium sulfate.

After the magnesium sulfate was removed by filtration, the toluene layer was concentrated by a rotary evaporator and then subjected to vacuum distillation to obtain 7.28 g (yield: 81.5%) of 3,4-dimethoxythiophene. The purity of its 3,4-dimethoxythiophene was 98.01% by gas chromatography.

The purity (concentration) by gas chromatography in the present invention was expressed by the area ratio of the peak area obtained by the detection device by FID using an Agilent 6890N network GC manufactured by Aglient Technologies.

Example 2

[Preparation of 3,4-dimethoxythiophene from 3,4-dibromothiophene]

After the dropwise addition of 3,4-dibromothiophene was completed in the case of Example 1, 33 g of methanol was distilled off (the concentration of sodium methoxide to the methanol solvent was 35.0% by weight based on the total amount of sodium methoxide before the reaction) , Heating and refluxing were carried out and the reaction was continued. When the reaction was traced by gas chromatography, 3,4-dibromothiophene and 3-bromo-4-methoxythiophene were found to be below the detection limit at the reflux start time of 5 hours.

Example 3

[Preparation of 3,4-dimethoxythiophene from 3,4-dibromothiophene]

After completion of dropwise addition of 3,4-dibromothiophene in the case of Example 1, 40.5 g of methanol was distilled off (the concentration of sodium methoxide to the methanol solvent was 40.0% by weight based on the total amount of sodium methoxide before the reaction) , Heating and refluxing were carried out and the reaction was continued. When the reaction was traced by gas chromatography, 3,4-dibromothiophene and 3-bromo-4-methoxythiophene became below the detection limit at the reflux time of 2 hours.

Comparative Example One

[Preparation of 3,4-dimethoxythiophene from 3,4-dibromothiophene]

28.1 g of sodium methoxide and 97 g of methanol were added to a 200 ml four-necked flask (the concentration of sodium methoxide in the methanol solvent was 22.5% by weight based on the total amount of sodium methoxide before the reaction) and dissolved at 50 캜 in an argon atmosphere.

After 1.0 g of cuprous bromide was added, 20 g of 3,4-dibromothiophene was added dropwise, and the reaction solution became colorless transparent to black. After completion of dropwise addition, the mixture was heated to reflux at 77 DEG C and the reaction was continued. The reaction was continued for 13 hours while tracking the reaction by gas chromatography.

After the magnesium sulfate was removed by filtration, the toluene layer was concentrated by a rotary evaporator and then subjected to vacuum distillation to obtain 9.64 g (yield: 81.0%) of 3,4-dimethoxythiophene. The purity of its 3,4-dimethoxythiophene was 61.42% by gas chromatography.

Comparative Example 2

[Preparation of 3,4-dimethoxythiophene from 3,4-dibromothiophene]

In the case of Comparative Example 1, 72.3 g of methanol (the concentration of sodium methoxide relative to the methanol solvent was 28.0 wt% based on the total amount of sodium methoxide before the reaction) was exactly the same as that of Comparative Example 1 . (DBrT) and 3-bromo-4-methoxythiophene (Br-MEOT) in the reaction solution at the point of 9 hours from the start of reflux The chromatographic concentrations were 0.20% and 3.29%, respectively.

Example 4

[Preparation of 3,4-ethylenedioxythiophene from 3,4-dimethoxythiophene]

The following production was carried out using 3,4-dimethoxythiophene prepared by the same production method as in Example 2 described above. This also applies to Examples 5 to 9 and Comparative Examples 3 to 9 described below.

First, 10.1 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 in an argon atmosphere.

And heated to 100 DEG C while distilling methanol at 95 deg. At 100 占 폚, the methanol flow terminated and the toluene reflux started.

The compositional change in the reaction solution was followed by gas chromatography using N, N-dimethylformamide as an internal standard. As a result, 3,4-dimethoxythiophene was found to be below the detection limit at the reflux time of 3 hours. Table 1 summarizes the relationship between the time from the start of reflux of toluene and the concentration of each component. In Table 1, EDOT, DMEOT, mono-substituent and mono-substituent are respectively substituted by ethylene glycol in one methoxy group of 3,4-ethylenedioxythiophene, 3,4-dimethoxythiophene and 3,4- And methoxy groups of both 3,4-dimethoxythiophene were replaced with ethylene glycol.

Table 1. Relationship between the time from the start of reflux of toluene and the concentration of each component in Example 4 Reaction time Gas Chromatography (%) Conversion Rate (%) Remaining rate (%) (h) DMEOT EDOT 1 substituent 2 substituent EDOT DMEOT One 8.55 77.30 9.76 4.39 56.08 6.00 2 0.36 98.87 0.28 0.49 78.09 0.33 3 0 100 0 0 73.72 0

Further, the conversion (%) in the table is theoretically 3, 4-ethylenedioxythiophene when N, N-dimethoxyformamide is measured as an internal standard by gas chromatography, And the ratio of the amount of 4-ethylenedioxythiophene.

The residual ratio (%) likewise represents the ratio of the actual amount of 3,4-dimethoxythiophene in the reaction solution to the amount of 3,4-dimethoxythiophene in theory.

The reaction mixture was diluted with water, the insoluble material was removed by filtration, the crude product was extracted from toluene, the toluene layer was washed with water, washed with aqueous sodium hydrogencarbonate solution, and then dried with magnesium sulfate.

After the magnesium sulfate was removed by filtration, the toluene layer was concentrated on 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 subjected to vacuum distillation to obtain 4.65 g (yield: 46.7%) of 3,4-ethylenedioxythiophene. The purity of its 3,4-ethylenedioxythiophene was 99.64% by gas chromatography.

Comparative Example 3

[Preparation of 3,4-ethylenedioxythiophene from 3,4-dimethoxythiophene]

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 were placed in a 100 ml four-necked flask, and the mixture was heated and stirred in an air atmosphere to reflux the toluene.

The reaction was followed by gas chromatography, and the reaction was terminated because the content of 3,4-dimethoxythiophene was 0.32% at 14 hours of reflux.

After the magnesium sulfate was removed by filtration, the toluene layer was concentrated with 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 subjected to vacuum distillation to obtain 0.87 g (yield: 44.0%) of 3,4-ethylenedioxythiophene. The purity of its 3,4-ethylenedioxythiophene was 96.28% by gas chromatography.

Example 5

[Preparation of 3,4-ethylenedioxythiophene from 3,4-dimethoxythiophene]

The procedure of Example 4 was exactly the same as that of Example 4 except that instead of p-toluenesulfonic acid monohydrate in Example 4, cuedemulsulfonic acid monohydrate (molar amount) was used and the compositional change in the reaction solution was changed to N, N-dimethylform Amide was traced by gas chromatography as an internal standard. The relationship between the time from the start of the reflux of toluene and the concentration of each component is summarized in Table 2.

Table 2. Relationship between the time from the start of reflux of toluene and the concentration of each component in Example 5 Reaction time Gas Chromatography (%) Conversion Rate (%) Remaining rate (%) (h) DMEOT EDOT 1 substituent 2 substituent EDOT DMEOT One 13.89 72.05 14.06 0 56.61 9.64 2 0.77 97.84 1.39 0 90.45 1.11 3 0 100 0 0 87.48 0

The crude product obtained by completely the same procedure as in Example 4 was subjected to vacuum distillation to obtain 6.49 g (yield: 65.2%) of 3,4-ethylenedioxythiophene. The purity of its 3,4-ethylenedioxythiophene was 99.86% by gas chromatography.

Example 6

[Preparation of 3,4-ethylenedioxythiophene from 3,4-dimethoxythiophene]

(Moles) of m-xylene-4-sulfonic acid monohydrate instead of the cuedemen sulphonic acid monohydrate of Example 5, the compositional change in the reaction solution was changed to N, N -Dimethylformamide < / RTI > was traced by gas chromatography as an internal standard. The relationship between the time from the start of the reflux of toluene and the concentration of each component is summarized in Table 3. < tb > < TABLE >

Table 3. Relationship between the time from the start of reflux of toluene and the concentration of each component in Example 6 Reaction time Gas Chromatography (%) Conversion Rate (%) Remaining rate (%) (h) DMEOT EDOT 1 substituent 2 substituent EDOT DMEOT One 12.14 50.72 17.44 19.70 53.67 11.09 2 1.42 89.79 3.44 5.63 84.89 1.69 3 0 99.58 0.42 0 88.55 0 4 0 100 0 0 83.37 0

Example 7

[Preparation of 3,4-ethylenedioxythiophene from 3,4-dimethoxythiophene]

The procedure of Example 5 was repeated except that mesylenesulfonic acid monohydrate (moles) was used in place of cesium mesylate monohydrate of Example 5 to change the composition in the reaction solution to N, N-dimethylformamide Was traced by gas chromatography as an internal standard. The relationship between the time from the start of reflux of toluene and the concentration of each component is summarized in Table 4.

Table 4. Relationship between the time from the start of reflux of toluene and the concentration of each component in Example 7 Reaction time Gas Chromatography (%) Conversion Rate (%) Remaining rate (%) (h) DMEOT EDOT 1 substituent 2 substituent EDOT DMEOT One 18.38 37.14 21.66 22.82 42.61 16.89 2 3.11 94.12 2.77 0 85.67 2.87 3 0.61 98.85 0.54 0 90.61 0.86 5 0 100 0 0 87.10 0

Comparative Example 4

[Preparation of 3,4-ethylenedioxythiophene from 3,4-dimethoxythiophene]

Naphthylenesulfonic acid monohydrate of the same substance (mol number) was used in place of the cuedemen sulphonic acid monohydrate of Example 5, and the same procedure as in Example 5 was carried out to change the composition in the reaction solution to N, N-dimethylform Amide was traced by gas chromatography as an internal standard. The relationship between the time from the start of the reflux of toluene and the concentration of each component is summarized in Table 5.

Table 5. Relationship between the time from the start of reflux of toluene and the concentration of each component in Comparative Example 4 Reaction time Gas Chromatography (%) Conversion Rate (%) Remaining rate (%) (h) DMEOT EDOT 1 substituent 2 substituent EDOT DMEOT One 3.08 78.58 3.92 14.42 72.71 3.11 2 0 100 0 0 80.02 0 3 0 100 0 0 71.53 0

Comparative Example 5

[Preparation of 3,4-ethylenedioxythiophene from 3,4-dimethoxythiophene]

The same procedure as in Example 5 was repeated except that dodecylbenzene sulfonic acid monohydrate having the same material (molar number) was used instead of the cuedemen sulphonic acid monohydrate in Example 5 to change the composition in the reaction solution to N, N-dimethylform Amide was traced by gas chromatography as an internal standard. The relationship between the time from the start of the reflux of toluene and the concentration of each component is summarized in Table 5.

Table 6. Relationship between the time from the start of reflux of toluene and the concentration of each component in Comparative Example 5 Reaction time Gas Chromatography (%) Conversion Rate (%) Remaining rate (%) (h) DMEOT EDOT 1 substituent 2 substituent EDOT DMEOT One 7.26 79.08 13.67 0 65.35 5.54 2 0.51 98.17 1.32 0 90.74 0.75 3 0 100 0 0 89.18 0

When dodecylbenzene sulfonic acid monohydrate was used, after completion of the reaction, the reaction mixture was diluted with water, insolubles were removed by filtration, the crude product was extracted from the toluene, and the toluene layer was washed with water. And the water layer could not be separated into liquids.

Comparative Example 6

[Preparation of 3,4-ethylenedioxythiophene from 3,4-dimethoxythiophene]

Except that (+) - 10-camphistsulfonic acid monohydrate of the same substance amount (mol number) was used instead of the cuedemen sulphonic acid monohydrate of Example 5, and the compositional change in the reaction solution was evaluated by N, N-dimethylformamide was traced by gas chromatography as an internal standard. Table 7 summarizes the relationship between the time from the start of reflux of toluene and the concentration of each component.

Table 7. Relationship between the time from the start of reflux of toluene and the concentration of each component in Comparative Example 6 Reaction time Gas Chromatography (%) Conversion Rate (%) Remaining rate (%) (h) DMEOT EDOT 1 substituent 2 substituent EDOT DMEOT One 37.02 11.72 27.47 23.79 15.36 36.67 2 30.41 26.30 36.04 21.62 30.89 23.96 3 19.88 42.09 29.26 17.24 43.96 15.65 4 11.57 56.29 19.30 12.84 58.14 11.28 5 5.57 92.95 1.48 0 87.98 5.46

Comparative Example 7

[Preparation of 3,4-ethylenedioxythiophene from 3,4-dimethoxythiophene]

Except that 2-amino-1-naphthalenesulfonic acid monohydrate of the same substance (mol number) was used in place of the cuedemen sulphonic acid monohydrate of Example 5, and the compositional change in the reaction solution was determined to be N, N-dimethylformamide was traced by gas chromatography as an internal standard. The relationship between the time from the start of the reflux of toluene and the concentration of each component is summarized in Table 8. < tb > < TABLE >

Table 8. Relationship between the time from the start of reflux of toluene and the concentration of each component in Comparative Example 7 Reaction time Gas Chromatography (%) Conversion Rate (%) Remaining rate (%) (h) DMEOT EDOT 1 substituent 2 substituent EDOT DMEOT One 76.11 1.28 17.23 5.38 7.30 74.50 2 40.53 28.98 22.88 20.79 34.01 29.17 3 12.52 70.74 7.3 11.78 67.11 9.41 4 4.49 90.75 1.43 3.33 79.13 3.85 5 2.45 96.94 0.61 0 84.49 2.31 6 1.83 98.17 0 0 80.87 1.78 7 1.72 98.28 0 0 82.57 1.71 8 1.70 98.30 0 0 87.15 1.77

Comparative Example 8

[Preparation of 3,4-ethylenedioxythiophene from 3,4-dimethoxythiophene]

The same operation as in Example 5 was carried out except that salicylic acid was used in place of the same amount of cesium (moles) of cesium sulfonic acid monohydrate in Example 5, and the compositional change in the reaction solution was measured by using N, N-dimethylformamide as an internal standard Followed by chromatography. Table 9 summarizes the relationship between the time from the start of reflux of toluene and the concentration of each component.

Table 9. Relationship between the time from the start of reflux of toluene and the concentration of each component in Comparative Example 8 Reaction time Gas Chromatography (%) Conversion Rate (%) Remaining rate (%) (h) DMEOT EDOT 1 substituent 2 substituent EDOT DMEOT 2 100 0 0 0 0 100 3 100 0 0 0 0 95.36

Example 8

[Preparation of 3,4-ethylenedioxythiophene from 3,4-dimethoxythiophene]

In Example 4, a case of using a 100 ml four-necked flask was explained. In Example 8, a case of using a 300 L tank is explained. The order of operations, the relationship between the quantity ratios, and the like are the same as those in the fourth embodiment.

3,4-Dimethoxythiophene and ethylene glycol react with each other in the 300 L reactor (1) to produce 3,4-ethylenedioxythiophene and, incidentally, methanol. Methanol in the reaction solution (20) is azeotropically mixed with toluene to obtain a mixed solution of methanol and toluene cooled by the cooler (3) through the distillation column (2). In addition, the cooler 3 has a structure capable of cooling internal steam by cooling water.

The mixed liquid 40 of methanol and toluene is sent to the water treatment tank 5 via the valve 10, the pipe 4 and the valve 11.

The water 30 is contained in the water treatment tank 5 and the mixed solution 40 of methanol and toluene is sent to the upper layer of the water treatment tank 5 after contacting the water 30.

Methanol contained in the mixed liquid 40 of the methanol and toluene is dissolved in the water 30 by contacting the mixed liquid 40 of methanol and toluene with the water 30.

The toluene solution 41 sent to the upper layer of the water treatment tank 5 is sent to the cooling tower 3 via the piping 7 and 8 by the liquid sending pump 6.

The toluene solution 41 sent to the cooling tower 3 after the water wash is brought into contact with the mixed liquid 40 of methanol and toluene. As a result, the concentration of methanol in the mixed liquid 40 of methanol and toluene returned to the 300 L reaction tank 1 decreases with the lapse of time.

By removing methanol from the reaction system as described above, the reaction time from 3,4-dimethoxythiophene to 3,4-ethylenedioxythiophene can be maintained within 5 hours even when the reaction case is expanded to 300 L.

The water 30 can be circulated to the cooling tower 3 in place of the toluene solution 41 after the water rinsing operation. However, in the case of the embodiment 8, the toluene solution 41 after the water rinsing is refluxed to the cooling tower 3 have. Even in this case, the reaction time from 3,4-dimethoxythiophene to 3,4-ethylenedioxythiophene can be maintained within 5 hours.

Example 9

[Preparation of 3,4-ethylenedioxythiophene from 3,4-dimethoxythiophene]

When the crude product of 3,4-ethylenedioxythiophene obtained in the case of Example 4 was distilled, polyethylene glycol having a number average molecular weight of 400 was added to the weight of 1/10 of the crude product and distilled.

In a 100 ml four-necked flask, there was no adherent completely, and 93 wt.% Of 3,4-ethylenedioxythiophene was obtained based on the weight of the crude product.

Then, 3,4-ethylenedioxythiophene was washed with water and then 3,4-ethylenedioxythiophene was distilled again. The purity of the 3,4-ethylenedioxythiophene was 99.80% by gas chromatography .

Comparative Example 9

[Preparation of 3,4-ethylenedioxythiophene from 3,4-dimethoxythiophene]

In the case of Example 9, a crude product of 3,4-ethylenedioxythiophene was distilled using propylene carbonate instead of polyethylene glycol having a number average molecular weight of 400, and 10% of propylene carbonate was mixed by gas chromatography .

Next, this 3,4-ethylenedioxythiophene was washed with water, but it was confirmed that propylene carbonate was mixed by about 3% by gas chromatography.

The same results were obtained when ethylene carbonate and sulfolane were used in place of propylene carbonate, respectively.

The present application is based on Japanese Patent Application No. 2008-006448, filed on January 16, 2008, the entirety of which is incorporated herein by reference and constitutes a part of this specification.

1 300L Reactor
2 distillation tower
3 chiller
4, 7, 8, 9 piping
5 water bath
6 Pumping pump
10 and 11 valves
20 Reaction solution
30 water
40 A mixture of methanol and toluene
41 A toluene solution after water rinsing
50 Stirrer

Claims

In general formula (1)

(Wherein X may be the same or different from each other and represents any one of a fluorine atom, a chlorine atom, a cancel atom or an oxo atom) with an alkali metal alkoxide in an alcohol-based solvent (2) by a step including an operation of distilling the alcohol-based solvent to the outside of the reaction system,

(Wherein R ₁ and R ₂ may be the same or different from each other and represent an alkyl group or an aryl group having 1 to 20 carbon atoms in the form of a straight or branched chain)
The dialkoxythiophene represented by the general formula (2) and the compound represented by the general formula (3)

(Wherein Z is each independently an oxygen atom or a sulfur atom, and R represents an alkylene group having 1 to 20 carbon atoms in the chain or branched chain or an arylene group having 1 to 20 carbon atoms) Equation (4)

(Wherein R ₁ and R ₂ may be the same or different from each other and represent an alkyl group or an aryl group having 1 to 20 carbon atoms in the chain or branched chain), while allowing the compound represented by the formula (5). &Lt; RTI ID = 0.0 >

(Wherein Z is each independently an oxygen atom or a sulfur atom, and R represents a linear or branched alkyl group having 1 to 20 carbon atoms or an arylene group having 1 to 20 carbon atoms)
Comprising the step of distilling a thiophene derivative represented by the general formula (5) in the presence of a polyol having a number average molecular weight ranging from 200 to 1000.

The method according to claim 1,
Wherein the step of obtaining the dialkoxythiophene represented by the general formula (2)
(a) an operation in which an alkali metal alkoxide is mixed with a thiophene halide represented by the general formula (1) in an alcoholic solvent and then the alcoholic solvent is removed from the reaction system,
(b) an operation of mixing the thiophene halide represented by the general formula (1) and the alkali metal alkoxide in an alcoholic solvent while stirring the alcoholic solvent to the outside of the reaction system, and
(c) an operation of distilling the alcoholic solvent from the alcoholic solution of the alkali metal alkoxide to the outside of the reaction system and then mixing the alkali metal alkoxide with the thiophene halide represented by the general formula (1) in the alcoholic solution,
&Lt; / RTI > and at least one selected from the group consisting of: < RTI ID = 0.0 >

The method according to claim 1,
Wherein the step of obtaining the dialkoxythiophene represented by the general formula (2) is carried out in the presence of the catalyst in such a manner that the concentration of the alkali metal alkoxide with respect to the alcoholic solvent is 15 wt% based on the total amount of the alkali metal alkoxide before the reaction % &Lt; / RTI > to 55% by weight, based on the total weight of the composition.

The method according to claim 1,
Wherein the step of obtaining the dialkoxythiophene represented by the general formula (2) is carried out in such a manner that the concentration of the alkali metal alkoxide with respect to the alcoholic solvent is 15% by weight to 50% by weight based on the total amount of the alkali metal alkoxide before the reaction Wherein the alcohol-based solvent is removed from the reaction system while increasing the amount of the thiophene derivative.

The method according to claim 1,
Wherein the step of obtaining the dialkoxythiophene represented by the general formula (2) is carried out in such a manner that the concentration of the alkali metal alkoxide with respect to the alcoholic solvent, based on the total amount of the alkali metal alkoxide before the reaction, To 50% by weight, based on the weight of the thiophene derivative.

The method according to claim 1,
Wherein the step of reacting the dialkoxythiophene represented by the general formula (2) with the compound represented by the general formula (3)
In general formula (6)

(In the formula, R ₃ represents a linear or branched alkyl group having 1 to 6 carbon atoms), a compound represented by the formula (7)

(Wherein R ₄ and R ₅ may be the same or different from each other and represent an alkyl group having 1 to 6 carbon atoms in the form of a straight or branched chain)

(Wherein R ₆ , R ₇ and R ₈ may be the same or different from each other and represent a linear or branched alkyl group having 1 to 6 carbon atoms) Lt; / RTI > is carried out in the presence of a carboxylic acid.

The method according to claim 1,
Wherein the step of reacting the dialkoxythiophene represented by the general formula (2) with the compound represented by the general formula (3)
(4) with an aromatic organic solvent, and a step of azeotroping the compound represented by the general formula
A step of obtaining a mixed solution of the aromatic organic solvent and the compound represented by the general formula (4) by cooling the entrained aromatic organic solvent and the compound represented by the general formula (4)
And a step of bringing the mixed liquid into contact with water to remove the compound represented by the general formula (4).

The method according to claim 1,
A process for producing a thiophene derivative, wherein the thiophene derivative represented by the general formula (5) is 3,4-ethylenedioxythiophene.

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