JP2763903B2 - Method of manufacturing conductor having self-doping function - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for producing a conductor having a self-doping function, and more particularly, to a method for producing a self-doping conductor, which is useful for various electronic components, electrodes, sensors, photoelectric conversion elements, and the like. The present invention relates to a method for manufacturing a conductor having a doping function.

[Conventional technology]

Conventionally, conductive polymers have been considered insoluble and infusible, but in recent years, polymerizable heterocyclic compounds such as thiophene and pyrrole have been given substituents such as long-chain alkyl groups, ketone groups or ether groups. Report that the polymer can be made into a polymer soluble in an organic solvent. Representative examples of these are disclosed in JP-A-62-220517.
JP-A-62-253617, K. Yoshin
o) The Chemistyr Expre
ss), Volume 1, p. 638 (1986), and the Journal of Chemical Society by MR Bryce et al., Chemical Communication (J. Ch.).
em.Soc., Chem.Commum.), 1987, p.466, and the like.

However, since these conductive polymers are made by using a polymer as a conductor by a doping operation using an acceptor or a donor, doping and undoping cannot be performed quickly. For example, a problem is that the response time of the electrochromic phenomenon is long. Have a point.

In order to improve the drawbacks of these conventional conductive polymers, there has been proposed a polymer having a self-doping function in which a counter ion imparting conductivity is covalently bonded to the polymer itself [for example, JP-A-63-39916. Gazette, and Journal of the American Chemical Society (F. Wudl) et al., J. Am. Chem. Soc, No. 109.
Vol., 1858 (1987), Journal of the Chemical Society, Chemical Communication by JR Reynolds et al. (J. Che)
m. Soc., Chem. Commun. 1987, p. 621)]. The polymer with a self-doping function obtained by these methods is a polymer electrolyte and is water-soluble, so it is not only excellent in cost performance at the time of shaping, but also as a pollution-free conductive polymer in terms of environmental protection. Attention has been paid.

In addition, in these polymers having a self-doping function, an anion group having a slow diffusion is previously bonded to a conjugate main chain by a covalent bond, and small mobile cations enter and exit with doping and undoping.
The response speed of the electrochromic phenomenon has been increased, and expectations for application as a display material are increasing.

However, the above-mentioned conductive polymer having a self-doping function is obtained by first deriving 3-thiophenealkanesulfonic acid and a salt thereof as a monomer into 3-thiophenealkanesulfonic acid ester, and then performing electrochemical polymerization. Because it is manufactured by hydrolysis,
To produce a conductive polymer having a self-doping function, a multi-step reaction process is required, and the production process is complicated,
In addition, there was a problem that the yield was low.

The biggest factor that causes such a problem is that 3-thiophenealkanesulfonic acid and its salt as a monomer have a hydrophilic group and cannot be electrochemically polymerized.
That is, since 3-thiophenealkanesulfonic acid and its salt are water-soluble monomers, the solvent capable of dissolving this monomer is limited to a polar solvent having a narrow electrochemical potential window. Even if it is performed, only decomposition of the solvent or elution of the oligomer is recognized,
No high molecular weight polymer could be obtained.

[Problems to be solved by the invention]

An object of the present invention is to overcome the drawbacks of the conventional method for producing a conductive polymer having a self-doping function, to achieve a high-molecular-weight, high-yield process in a shorter process than the conventional production method, and at a low cost by a simple method. An object of the present invention is to provide a method for manufacturing a conductor having a self-doping function. The term “high molecular weight” as used herein means that the absorption maximum based on the π-π ^* transition in the ultraviolet-visible absorption spectrum of the polymer solution is at least 400 nm or more.

[Means for solving the problem]

The present inventors have conducted intensive studies on oxidizing agents having various oxidation potentials in order to directly polymerize thiophenes. As a result, oxidizing transition metal halides in thiophenes-soluble polar solvents were conducted. By conducting the reaction in the presence of a compound, the conductive polymer having a high molecular weight self-doping function is easily polymerized in a short process,
The present inventors have found that they can be obtained at a high yield, and have reached the present invention.

That is, the present invention uses the general formula (Wherein, R is a linear or branched alkylene group which may contain a carbonic 1 to 10 ether bond or amide bond, M is a proton, an alkali metal cation or an alkaline earth metal cation, and m is 1 or 2.) The thiophenes represented by are chemically polymerized in a polar solvent in the presence of an oxidizing transition metal halide, and then the product is treated with a basic substance and then treated with a cation-type ion exchange resin. The present invention relates to a method for manufacturing a conductor having a self-doping function.

Hereinafter, a method for manufacturing a conductor having a self-doping function according to the present invention will be described.

First, in the present invention, thiophenes represented by the above general formula are chemically polymerized in a polar solvent in the presence of an oxidizable transition metal halide. The thiophenes represented by the above general formula are compounds having a hydrophilic group at the 3-position of the thiophene ring, such as 3-thiophene methanesulfonic acid, 3-thiopheneethanesulfonic acid, 3-thiophenepropanesulfonic acid, and 3-thiophene. Butanesulfonic acid, 3-thiophenpentanesulfonic acid, 3-thiophenoxymethanesulfonic acid, 3-thiophenoxyethanesulfonic acid, 3-thenyloxymethanesulfonic acid, and their sodium, potassium, and calcium salts.

The polar solvent used in the present invention is a solvent in which thiophenes are soluble, for example, water, alcohol solvents such as methanol and ethanol, N, N-dimethylformamide, dimethyl sulfoxide, acetonitrile, and non-aqueous solvents such as propylene carbonate. Polar solvents.

Examples of the oxidative transition metal halide (hereinafter, referred to as an oxidizing agent) used in the present invention include ferric chloride, molybdenum chloride, ruthenium chloride and the like.

The concentration of the thiophenes during the chemical polymerization is 0.001 to 10 mol /, particularly preferably 0.5 to 5 mol / in the polar solvent.
It is. The amount of oxidizing agent used is
An equivalent amount of 2 to 10 times is effective, and the amount of the polar solvent used is an amount at which the oxidizing agent becomes a saturated concentration or more. If the amount of the oxidizing agent used is less than 2 equivalents, the polymerization stops at the oligomer stage and no high molecular weight product can be obtained. The reaction temperature is preferably from -20 to 60C. The reaction temperature is-
If the temperature is lower than 20 ° C, the reaction rate is extremely slow.
At a temperature higher than 60 ° C., it is difficult to obtain a high molecular weight polymer. The reaction time is preferably from 1 hour to 14 days. The order of adding the thiophenes and the oxidizing agent is not particularly limited.

Next, in the present invention, the product obtained by chemical polymerization is treated with a basic substance, and then treated with a cation-type ion exchange resin.

In the polymer obtained by the chemical polymerization under the above conditions, M shown in the above general formula is replaced by a transition metal ion in an oxidizing agent, which is an excess of a basic substance such as an alkali metal and When an alkaline earth metal hydroxide, alkali metal carbonates such as sodium carbonate and sodium hydrogen carbonate, ammonia, and organic amines such as triethylamine and pyridine are added, M in the general formula corresponds to an alkali metal ion. , Are easily replaced by alkaline earth metal ions and quaternary ions of amines, and the transition metal ions precipitate as hydroxides and the like. Next, the liquid from which the precipitate has been removed by filtration is passed through a cation-type ion exchange resin (for example, commercially available product Amberlite IR-120) to perform ion exchange. First, M in the general formula is exchanged for a proton by passing through a proton-type ion exchange resin, and further, transition metal ions contained in a trace amount in the liquid are captured and removed. By drying the aqueous polymer solution after treatment with a proton-type ion exchange resin, a high-molecular-weight conductor having a self-doping function in which M in the general formula is a proton can be produced. On the other hand, secondly, the aqueous solution after the treatment with the proton-type ion exchange resin is converted into a target alkali metal (for example, lithium, sodium and potassium) ion, alkaline earth metal (for example, magnesium and calcium) ion or amine. After passing through an ion exchange resin converted to quaternary ions, the polymer is reprecipitated using a poor solvent for the polymer (for example, an organic solvent such as methanol, ethanol and acetone), and the deposited precipitate is collected by filtration. A high molecular weight conductor having a self-doping function in which M in the general formula is substituted with an alkali metal ion or an alkaline earth metal ion can be produced.

〔The invention's effect〕

As described above, thiophenes for a conductor having a self-doping function which could not be electrochemically polymerized in a polar solvent in the past, by applying the method of the present invention,
It allows direct polymerization in polar solvents. Furthermore, according to the production method of the present invention, the steps described in the conventional method, that is, a sulfonic acid and a salt thereof, which are monomers for a conductor having a self-doping function, are once converted into a sulfonyl chloride form and a methyl sulfonate form. Then, the four steps of electrochemically polymerizing the methyl sulfonate to form a polymer and then hydrolyzing it to obtain a conductor having the desired self-doping function are reduced to two steps of chemical polymerization and ion exchange treatment. As a result, the yield was greatly improved, and it became possible to produce a conductor having a self-doping function in which the conjugated chain length of the produced polymer was extended.

〔Example〕

Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples.

Example 1 Poly [sodium 3-thiophenepropanesulfonate]
Preparation of a solution A solution consisting of 20 mmol of sodium 3-thiophenepropanesulfonate and 60 ml of methanol was added to 40 ml of a methanol solution containing 0.16 mol of ferric chloride (8 equivalents relative to the monomer) under a nitrogen stream. Stir at room temperature for 7 days,
After the reaction solution was solidified, the solid was washed three times with 200 ml of acetone and dried at room temperature under reduced pressure to obtain 5.20 g of a black powder.
After suspending 5.09 g of this powder in 100 ml of distilled water, 0.1N-Na
When 400 ml of an OH aqueous solution was added with vigorous stirring, the solution turned deep red. After insoluble iron hydroxide was removed by filtration through filter paper, the solution was passed through a proton-type ion exchange resin (IR-120, commercially available product) 80 g to obtain a brown eluate. This aqueous solution of the proton-type polymer is passed through 80 g of sodium-type ion-exchange resin (IR-120), concentrated, dried and dissolved in a small amount of residual distilled water. The precipitate was collected by filtration. After vacuum drying at room temperature, 3.82 g (yield 76.7%) of a sodium salt self-doping polymer was obtained.

Elemental analysis results for poly [sodium 3-thiophenepropanesulfonate] are calculated values: C: 33.10% H: 3.61% Na: 8.4% S: 23.2% Calculation for molecular formula C ₇ H ₇ S ₂ O ₃ Na · 2H ₂ O The value is C: 32.06% H: 4.22% Na: 8.77% S: 24.45
% Met.

In addition, it can be seen from the ultraviolet-visible spectrum shown in FIG. 1 that a polymer having a high molecular weight and a self-doping function was obtained.

Example 2 Poly [sodium 3-thiophenepropanesulfonate]
To a 0.5 ml suspension of 7.0 mol / ferric chloride (8 equivalents relative to monomer) was added an aqueous solution consisting of 0.44 mmol of thiophene-3- (sodium 3-propanesulfonate) and 0.5 ml of water under nitrogen. Added under airflow. The mixture was stirred at room temperature for 18 hours.
It was washed twice and dried under reduced pressure at room temperature to obtain 97.9 mg of a black powder. After suspending 97.9 mg of this powder in 1.0 ml of distilled water, 0.1
When 6.4 ml of an N-NaOH aqueous solution was added with vigorous stirring, the color turned into deep red. After removing insoluble iron hydroxide by filtration through a filter paper, a proton-type ion-exchange resin (IR-120,
When passed through 5 g of a commercial product, a brown eluate was obtained. After passing the aqueous solution of the proton-type polymer through 5 g of sodium-type ion exchange resin (IR-120), the residue obtained by concentration to dryness is dissolved in a small amount of distilled water, and the residue is dissolved in 20 ml of methanol containing 0.66 mmol sodium hydroxide. Reprecipitated and collected by filtration. After vacuum drying at room temperature, 82.1 mg (85.7% yield) of a sodium salt self-doping polymer was obtained.

The results of elemental analysis of poly [sodium 3-thiophenepropanesulfonate] were almost the same as the results of elemental analysis of Example 1.

Further, it can be seen from the ultraviolet-visible spectrum shown in FIG. 2 that a polymer having a high molecular weight and a self-doping function was obtained.

Examples 3 to 8 Poly [sodium 3-thiophenepropanesulfonate]
Production was carried out in the same manner as in Example 1 except that the reaction temperature, the reaction time, and the amount of the oxidizing agent used were changed as shown in Table 1. The results are shown in Table 1.

Comparative Example 3-Electrochemical Polymerization of Sodium 3-thiophenepropanesulfonate Electrochemical polymerization was performed using sodium 3-thiophenepropanesulfonate as a monomer and a supporting electrolyte in a 0.1 mol / methanol solution. Using a graphite foil (commercially available) for the cathode and ITO glass for the anode, a current of 400 coulombs (the amount of electricity that causes all the monomers to be electrolytically oxidized) was applied, but a small amount of the oligomer shown in the ultraviolet-visible absorption spectrum of FIG. Only a high molecular weight polymer was not obtained.

[Brief description of the drawings]

FIGS. 1, 2 and 3 are ultraviolet-visible absorption spectra of the polymers obtained in Examples 1, 2 and Comparative Examples, respectively, in an aqueous solution.

──────────────────────────────────────────────────続 き Continuation of the front page (72) Haruo Yoshida, Inventor 2 Oita-shi, Oita City, Oita Prefecture Showa Denko KK Oita Research Institute (56) References JP-A-63-39916 (JP, A) International Publication 87 / 5914 (WO, A1) (58) Field surveyed (Int. Cl. ⁶ , DB name) C08G 61/12 H01B 1/12

Claims (3)

(57) [Claims] (1) General formula (Wherein, R is a linear or branched alkylene group which may contain an ether bond or an amide bond having 1 to 10 carbon atoms, M is a proton, an alkali metal cation or an alkaline earth metal cation, and m is 1 or Is chemically polymerized in a polar solvent composed of water or an alcohol solvent in the presence of an oxidizable transition metal halide, and then the product is treated with a basic substance.
A method for producing a conductor having a self-doping function, characterized by performing an ion exchange treatment. 2. The method for producing a conductor having a self-doping function according to claim 1, wherein the ion exchange treatment is performed with an ion exchange resin. 3. The method for producing a conductor having a self-doping function according to claim 2, wherein the ion exchange resin is a cation type ion exchange resin.