JPH10259249A - Purification of polyaniline - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a polyaniline solution purified without being separated as solid polyaniline and finally having excellent physical properties by purifying the polyaniline dissolved or dispersed in the solution by means of dialysis or ultrafinltration. SOLUTION: The solution or dispersion of the polyaniline and/or its derivative, containing a dopant, preferably at least one of a dopant of the formula [R<1> , R<1> ' are each H, a 5-15C alkyl, alkenyl, etc.; (m), (m') are each an integer of 0-5] and a compound of the formula]: R<2> OSO3 H (R<2> is an 8-40C alkyl, alkenyl, etc.), is purified by means of dialysis and/or ultrafiltration. Since the polyaniline can thus be purified in the solution or dispersion state without requiring a complicated operation, the finally obtained polyaniline solution has excellent physical properties.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a method for purifying polyaniline and / or a derivative thereof dispersed in an aqueous solvent in a doped state (a state in which a dopant is present).

[0002]

2. Description of the Related Art Since polyaniline, which is a conductive polymer, is generally infusible and insoluble, it has poor processability, and a method for solubilizing or dispersing polyaniline has been desired.

As for water-soluble polyaniline, a self-doping type water-soluble polyaniline in which a sulfonic acid group serving as a dopant is directly bonded to a polymer skeleton (Japanese Patent Laid-Open No. 5-17 / 1990).
8989) has been proposed, but the manufacturing process is complicated and there is a problem in cost.

The present inventors have also conducted intensive studies to develop an inexpensive conductive polyaniline which is soluble or dispersed in an aqueous solvent in a doped state, and as a result, a specific dopant is used to make polyaniline or a derivative thereof soluble in water or doped with water. It has been found that it can be dispersed.

However, since these polyanilines are dissolved or dispersed in the polymerization solution, it has been difficult to separate them from reaction impurities. For centrifugation or precipitation filtration, the addition of a poor solvent is indispensable, and there is a problem that polyaniline once separated as a solid does not completely redissolve or redisperse.

[0006]

SUMMARY OF THE INVENTION In view of the above problems, an object of the present inventor is to remove polyaniline and / or a derivative thereof dissolved or dispersed in an aqueous solvent in a dope state without separating it into a solid without separating it. Another object of the present invention is to provide a method for purifying a dispersion as it is.

[0007]

Means for Solving the Problems As a result of intensive studies, the present inventors have purified polyaniline and / or a derivative thereof dissolved or dispersed in an aqueous solvent in a dope state as a solution or dispersion. A method was found and led to the present invention. That is, the present invention relates to a method for purifying polyaniline, comprising purifying a solution or dispersion of polyaniline and / or a derivative thereof in which a dopant coexists by dialysis and / or ultrafiltration. Either dialysis or ultrafiltration may be performed, or both may be used in combination. The dopant used is preferably at least one selected from the following formulas (I) to (IV).

[0008]

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In the formula, R ¹ and R ¹ ′ may be the same or different and may be hydrogen or an alkyl group having 5 to 15 carbon atoms, an alkenyl group, an alkylthioalkyl group, an aryl group, an alkylaryl group, It represents an arylalkyl group, an alkoxyalkyl group, or an aryloxyalkyl group.
m and m 'show the integer of 0-5.

[0010]

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In the formula, R ² represents an alkyl group having 8 to 40 carbon atoms, an alkenyl group, an alkylthioalkyl group, an aryl group, an alkylaryl group, an arylalkyl group, an alkoxyalkyl group, or an aryloxyalkyl group.

[0012]

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In the formula, R ³ represents an alkyl group having 5 to 20 carbon atoms, an alkenyl group, an alkylthioalkyl group, an aryl group, an alkylaryl group, an arylalkyl group, an alkoxyalkyl group or an aryloxyalkyl group;
Represents an integer of 1 to 5.

[0014]

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In the formula, M represents a monovalent cation (excluding a proton) such as a sodium ion, a potassium ion, and an ammonium ion. R ⁴ and R ⁴ ′ may be the same or different, and include hydrogen, an alkyl group, an alkenyl group, an alkoxy group, an alkylthio group, an alkylthioalkyl group, an aryl group, an alkylaryl group, an arylalkyl group,
It represents an alkylsulfinyl group, an alkoxyalkyl group, an aryloxyalkyl group, an alkylsulfonyl group, an alkoxycarbonyl group, a carboxyl group, a nitrile group, a hydroxy group, a nitro group or a halogen.

Preferred R ⁴ and R ⁴ ′ are hydrogen, an alkyl group,
Alkoxy group, alkylthio group, alkylthioalkyl group, alkylsulfinyl group, alkoxyalkyl group,
Aryloxyalkyl group, alkylsulfonyl group, alkoxycarbonyl group, carboxyl group, nitrile group,
Shows a hydroxy group, nitro group or halogen. l is 1
And integers of q and q ′ represent integers of 1 to 6.

The aniline or its derivative used in the oxidative polymerization may be one kind or two or more kinds, and has a structure represented by the following formula (V).

[0018]

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In the formula, r represents an integer of 0 to 5. R ⁵ may be the same or different, and each represents a hydrogen, an alkyl group,
Alkenyl group, alkoxy group, alkanoyl group, alkylthio group, aryloxy group, alkylthioalkyl group, aryl group, alkylaryl group, arylalkyl group, alkylsulfinyl group, alkoxyalkyl group, alkylsulfonyl group, alkoxycarbonyl group,
It is selected from an amino group, an alkylamino group, a dialkylamino group, an arylthio group, an arylsulfinyl group, an arylsulfonyl group, a carboxyl group, a halogen group, a cyano group, a haloalkyl group, a nitroalkyl group, and a cyanoalkyl group.

Specific examples include aniline, o-toluidine, m-toluidine, o-ethylaniline, m-toluidine,
Ethylaniline, o-ethoxyaniline, m-butylaniline, m-hexylaniline, m-octylaniline, 2,3-dimethylaniline, 2,5-dimethylaniline, 2,5-dimethoxyaniline, o-cyanoaniline, , 5-dichloroaniline, 2-bromoaniline,
5-chloro-2-methoxyaniline, 3-phenoxyaniline and the like.

As the oxidizing agent, ammonium peroxodisulfate, hydrogen peroxide, ferric chloride and the like are used, and preferably, ammonium peroxodisulfate is used, but it is not particularly limited.

As a method for obtaining the polyaniline of the present invention, there is a method of adding an oxidizing agent and a solution of a protonic acid or a solution of an oxidizing agent to a solution or suspension of aniline or an aniline derivative and a protonic acid. For polymerization,
The usual polymerization conditions apply. For example, the reaction temperature is between -10 ° C and 40 ° C, and the reaction time is between 30 minutes and 4 minutes.
The reaction mixture is stirred under normal pressure for a period of 8 hours.

The protonic acid added during the oxidative polymerization is not limited as long as the acid dissociation constant pKa is 4.0 or less, and inorganic acids such as hydrochloric acid, sulfuric acid, nitric acid and perchloric acid, and benzenesulfonic acid And organic acids such as p-toluenesulfonic acid, m-nitrobenzoic acid and trichloroacetic acid, and polymer acids such as polystyrenesulfonic acid, polyvinylsulfonic acid and polyvinylsulfuric acid.

The aqueous solvent in which the polyaniline composition of the present invention can be dissolved or dispersed means water or a mixed solvent with water and an organic solvent miscible with water. The ratio between water and the organic solvent is not particularly limited. Examples of the organic solvent include ethers such as tetrahydrofuran and dioxane, alcohols such as methanol, ethanol, isopropyl alcohol and 2-n-butoxyethanol, nitriles such as acetonitrile, ketones such as acetone, formic acid, acetic acid, and propion. Carboxylic acids such as acids, N-methylpyrrolidone,
Polar solvents such as dimethylformamide and dimethylsulfoxide can be used. In any case, those having low toxicity are preferable.

Since the aqueous polyaniline of the present invention is dissolved or dispersed in a polymerization solution, it is necessary to purify the aqueous polyaniline in a liquid state such as dialysis or ultrafiltration. The method of reducing the solubility or dispersibility by adding a poor solvent or the like, and then separating the polyaniline by filtration or centrifugation and then re-dissolving or re-dispersing in an aqueous solvent is complicated, and the resulting liquid Will have poor physical properties.

[0026]

EXAMPLES The present invention will be described below with reference to examples.
The present invention is not limited by these examples.

<Synthesis Example 1> 2.5 g of 2,2′-dinaphthylmethane-6,6′-disulfonate sodium salt was passed over a mixed solution of 10 ml of distilled water and 70 ml of methanol, and the mixture was ion-exchanged with an ion exchange resin (Amberlyst 15). 37.5 g)
Stirred at room temperature for 15 minutes. After filtration with a glass filter,
Titration with a 0.02 N aqueous sodium hydroxide solution confirmed quantitatively that the sulfo sodium group was converted to a sulfonic acid group. The solvent is distilled off, and the residue is dried.
The structure was confirmed by H-NMR and IR. 2,2 'obtained
-2.4 g of dinaphthylmethane-6,6'-disulfonic acid
And 2.7 g of 2,2'-dinaphthylmethane-6,6'-disulfonate sodium salt were added to 10 ml of distilled water and dissolved, and the mixture was stirred at room temperature for 30 minutes to reach ion equilibrium to obtain a dopant solution.

<Example 1> 13 ml of the dopant (molecular weight 450) solution of Synthesis Example 1 and 0.5 g of aniline were added, and 0 ° C.
And a small amount of iron (II) sulfate was added. A solution prepared by dissolving 1.2 g of ammonium persulfate in 4 ml of water was previously dissolved in 0 ml.
After cooling to 0 ° C, the solution was added dropwise over 10 minutes. The reaction mixture was kept at 0 ° C. and stirred for 20 hours. The resulting doped polyaniline was dissolved in water and dialyzed for 2 days (Spectrum M
edical Industries Spectra / Pore 7; FE-0521-
05). A portion of the solution was vacuum dried to determine the solids concentration.

The aqueous solution of the doped polyaniline obtained above and an aqueous dispersion of the Byron resin MD1200 manufactured by Toyobo Co., Ltd. were mixed so that the weight ratio of the doped polyaniline became 30%, and a 1% concentration solution was prepared and thinned. Was. The measured surface resistance was 1.5 × 10 ⁹ Ω / □.

Example 2 13.23 g of sodium 2,2'-dinaphthylmethane-6,6'-disulfonate was dissolved in 170 g of deionized water, and 1.416 g of sulfuric acid and 2.347 g of aniline were added. Cooled to 0 ° C. 5.751 g of ammonium peroxodisulfate is added to 30 parts of deionized water.
g was previously cooled to 0 ° C.
It was dropped in 5 minutes. The reaction mixture was kept at 0 ° C. and stirred for 20 hours. The resulting doped polyaniline was dissolved in water and purified by ultrafiltration until the concentration became 1/32. A portion of the solution was vacuum dried to determine the solids concentration.

The solution of the doped polyaniline obtained in Example 1 and Vylonal MD-1200 manufactured by Toyobo Co., Ltd. were mixed so that the solid fraction ratio of polyaniline and the byron resin was 30:70, and water / isopropyl alcohol (1: 1) was mixed. ; V / v)
A solution was prepared, applied on a polyethylene terephthalate film, thinned (0.1 mm in thickness), and the surface resistance was measured to be 1.7 × 10 ⁹ Ω / □.

Example 3 3 g of a sodium sulfonic acid compound of the following formula (VI), 0.4 ml of concentrated hydrochloric acid, 0.4 g of aniline.
47 g and 15 ml of distilled water were mixed in a 100 ml three-necked flask and cooled to 0 ° C. 5 ml of an aqueous solution of 1.15 g of ammonium peroxodisulfate was previously cooled to 0 ° C., and added dropwise to the above compound over 10 minutes. The reaction mixture is 0
The mixture was stirred for 20 hours while maintaining the temperature. Dialysis was performed for 2 days (Spectra / Pore 7 manufactured by Spectrum Medical Industries; FE-0521-05).

[0033]

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A portion of the solution was dried to determine the solids concentration. This aqueous dispersion of the doped polyaniline was applied on polyethylene terephthalate and dried at 120 ° C. for 1 hour to obtain a thin film having a thickness of 1 μm. When the conductivity of the obtained thin film was measured, it was 1.2 × 10 ⁻² S / cm.

Example 4 A polyaniline was synthesized in the same manner as in Example 3 using the compound of the following formula (VII). The conductivity of the produced polyaniline was 1.7 × 10 ⁻² S / cm.

[0036]

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Example 4 Using the compound of the following formula (VIII), polyaniline was synthesized in the same manner as in Example 3.
The conductivity of the produced polyaniline is 2.9 × 10 ^-2 S / cm.
Met.

[0038]

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Comparative Example 1 3.31 g of 2,2′-dinaphthylmethane-6,6′-disulfonate sodium salt was dissolved in 40 g of deionized water, and 0.354 g of sulfuric acid and 0.588 g of aniline were added. Cooled to 0 ° C. A solution prepared by dissolving 1.438 g of ammonium peroxodisulfate in 10 g of deionized water was cooled to 0 ° C. in advance, and added dropwise over 10 minutes. The reaction mixture was kept at 0 ° C. and stirred for 21 hours. The resulting doped polyaniline was dissolved in water. A portion was centrifuged and redissolved in deionized water for purification. The remainder was added with 60 vol% of acetone, filtered through a G4 glass filter, and then redissolved in deionized water for purification. A portion of each solution was vacuum dried to determine the solids concentration.

<Comparative Example 2> The solution of the doped polyaniline obtained in Comparative Example 1 and Vylonal MD-1200 manufactured by Toyobo Co., Ltd.
Has a solid fraction ratio of polyaniline and byron resin of 30:70
And then prepared as a water / isopropyl alcohol (1: 1; v / v) solution, applied on a polyethylene terephthalate film, thinned (0.1 mm thick), and the surface resistance was measured. , 6.7 × 1 each
⁰⁹ Ω / □ (purification by centrifugation), 3.7 × 10 ⁹ Ω / □
(Filtered with a glass filter).

[0041]

According to the method for purifying polyaniline according to the present invention, the polyaniline dissolved or dispersed in the polymerization solution can be purified as a solution or dispersion without being separated as a solid. It is excellent in physical properties.

Claims (6)

[Claims] 1. A method for purifying polyaniline, comprising purifying a solution or dispersion of polyaniline and / or a derivative thereof in which a dopant coexists by dialysis and / or ultrafiltration. 2. The method for purifying polyaniline according to claim 1, wherein the dopant is represented by the formula (I). Embedded image In the formula, R ¹ and R ¹ ′ may be the same or different, and may be hydrogen or an alkyl, alkenyl, alkylthioalkyl, aryl, alkylaryl, or arylalkyl group having 5 to 15 carbon atoms. , An alkoxyalkyl group, and an aryloxyalkyl group. m and m 'are 0
Indicates an integer of 5. 3. The method for purifying polyaniline according to claim 1, wherein the dopant is represented by the formula (II). Embedded image In the formula, R ² represents an alkyl group having 8 to 40 carbon atoms, an alkenyl group, an alkylthioalkyl group, an aryl group, an alkylaryl group, an arylalkyl group, an alkoxyalkyl group, or an aryloxyalkyl group. 4. The method for purifying polyaniline according to claim 1, wherein the dopant is represented by the formula (III). Embedded image In the formula, R ³ represents an alkyl group having 5 to 20 carbon atoms, an alkenyl group, an alkylthioalkyl group, an aryl group, an alkylaryl group, an arylalkyl group, an alkoxyalkyl group, an aryloxyalkyl group, and p represents 1 to 5 Indicates an integer. 5. The method for purifying polyaniline according to claim 1, wherein the dopant is represented by the formula (IV). Embedded image In the formula, M represents a monovalent cation (excluding a proton).
R ⁴ and R ⁴ ′ may be the same or different, and include hydrogen, an alkyl group, an alkenyl group, an alkoxy group, an alkylthio group, an alkylthioalkyl group, an aryl group, an alkylaryl group, an arylalkyl group, an alkylsulfinyl group, Alkoxyalkyl group, aryloxyalkyl group, alkylsulfonyl group, alkoxycarbonyl group,
It represents a carboxyl group, a nitrile group, a hydroxy group, a nitro group or a halogen. l represents an integer of 1 to 4, and q and q 'represent an integer of 1 to 6. 6. The method for purifying polyaniline according to claim 1, wherein the dopant contains at least one of formulas (I), (II), (III) and (IV). .