JP2586387B2 - Method for producing conductive polymer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a conductive polymer used as a conductive material in the field of electronics, and more particularly to a method for producing a conductive polymer having high conductivity and excellent stability at high temperatures. About.

[0002]

2. Description of the Related Art Known methods for producing a conductive polymer include an electrolytic polymerization method in which an aromatic compound is electrochemically anodized and polymerized, and a polymerization method using an oxidizing agent. this house,
In the electrolytic polymerization method, a film having high conductivity can be obtained by a method in which an electrode pair is immersed in an electrolyte solution containing a monomer to be polymerized, and anodically electrochemically polymerized. For example, Synthetic Metal by Sato et al., Vol. 14, 271
Page (1986) states that the conductivity of pyrrole using p-toluenesulfonate as an electrolyte is 500 S / c.
m of polypyrrole are described.

On the other hand, the synthesis of a conductive polymer using an oxidizing agent is carried out by oxidatively polymerizing a monomer with an oxidizing agent such as ferric chloride. Journal of by Walker
Polymer Science, Part A, Po
Lyr chemistry, Vol. 26, p. 1285 (1988) describes a polymerization example of pyrrole using ferric dodecylbenzenesulfonate as an oxidizing agent. Japanese Patent Application Laid-Open No. 4-46214 discloses a method for synthesizing polypyrrole in which a ferric dodecylbenzenesulfonate solution and a methanol solution of pyrrole are mixed at -30 ° C or lower, and the temperature is raised to -20 ° C or higher to polymerize. A method for manufacturing a solid electrolytic capacitor is disclosed. However, this publication does not show a specific method for obtaining a highly conductive polymer.

[0004]

In the above-described method for synthesizing a conductive polymer, in the synthesis of a conductive polymer by an electrolytic polymerization method, a reaction proceeds only on the electrode surface, and therefore a conductive support must be used. A complicated operation is required, for example, the polymerization product must be peeled off from the electrode.
In addition, it was difficult to obtain a large amount of powdery product by this method. On the other hand, in the polymerization of pyrrole with an oxidizing agent, although powdery polypyrrole can be synthesized in a large amount, there is a problem that the conductivity of the product is remarkably small as compared with the electrolytic polymerization method.

An object of the present invention is to solve the above-mentioned problems of the prior art and to provide a method for producing a conductive polymer having high conductivity by a simple method regardless of the presence or absence of a support.

[0006]

Means for Solving the Problems The present inventors have conducted various studies to solve the above-mentioned problems. As a result, an oxidizing agent having a sulfonic acid compound as an anion and an expensive transition metal as a cation and pyrrole or a derivative thereof are -3.
The present inventors have found that the above object can be achieved when a method for producing polypyrrole or a polypyrrole derivative to be polymerized from a polymerization solution mixed at a temperature of 0 ° C. or lower is performed under specific conditions. That is, the present invention relates to a method for producing a polypyrrole or a polypyrrole derivative, wherein a sulfonic acid compound is used as an anion, and an oxidizing agent having an expensive transition metal as a cation and pyrrole or a derivative thereof are polymerized from a polymerization solution mixed at -30 ° C or lower. Polymerization solution is 2% polymerization amount
This is a method for producing a conductive polymer containing water as described above, having an oxidizing agent concentration of 20% or more and a mixing molar ratio of monomers to the oxidizing agent of 3 or more.

Although the polymerization temperature of the present invention is not particularly limited,
The temperature is preferably 25 ° C. or less from the conductivity of the conductive polymer to be generated.

In the present invention, the sulfonic acid compound which is an anion constituting the oxidizing agent is not particularly limited as long as it has a sulfonic acid group, and p-toluenesulfonic acid ion, ethylbenzenesulfonic acid ion, octylbenzenesulfonic acid ion, alkylbenzene sulfonate ion such as dodecylbenzenesulfonic acid ion, beta-naphthalene sulfonic acid ion, naphthalenesulfonic acid ion, such as butyl naphthalenesulfonic acid ion, sulfosuccinic acid ion, organic sulfonate ion, such as N- acyl sulfonate ion, C ₈ -C ₁ but including _two alkyl sulfonate ion or α- olefin sulfonate ion and the like, aromatic sulfonic acid anion is particularly preferred to have an alkyl substituent such as alkyl benzene sulfonate ion. Ag ⁺ , Cu ^{2 +} , Fe ^{3 +} , and expensive transition metal ions that are cations constituting the oxidizing agent
Al ^{3 +} , Ce ^{4 +} , W ^{6 +} , Mo ^{6 +} , Cr ^{6 +} , M
n ^{7 +} , Sn ^{4 + and the} like, and in particular, Fe ^{3 +} ,
And Cu ^{2 +} are preferred.

In the present invention, the pyrrole derivative is a compound having a pyrrole skeleton and having a substituent at the 3- or N-position, or a mixture of these with pyrrole, wherein the substituent is a hydroxyl group, an acetyl group, a carboxyl group. Group,
And an alkyl group.

In the present invention, a solution is prepared by mixing the above-mentioned pyrrole or its derivative and the oxidizing agent at -30 ° C. or lower. The solvent is not particularly limited as long as it can dissolve both pyrrole or its derivative and the oxidizing agent. Not done. Examples of these are methanol, ethanol, isopropyl alcohol, acetone, methyl ethyl ketone,
Examples include diethyl ether, acetonitrile, tetrahydrofuran and the like.

In the present invention, a solution obtained by mixing pyrrole or a derivative thereof and an oxidizing agent contains 2% by weight or more of water. However, a completely dehydrated solution does not produce a uniform solution even at −30 ° C. or less even if it is dehydrated. According to the study of the present inventors, if the amount of water in the reaction solution is 2% by weight or more, it does not affect the conductivity of the generated conductive polymer. Below this, the polymerization proceeds before the oxidizing agent and the monomer become a homogeneous solution, and the conductivity decreases.

In the present invention, the polymerization atmosphere is not particularly limited.

The present invention will be described below with reference to the drawings. FIG. 1 shows the relationship between the concentration of ferric dodecylbenzenesulfonate and the conductivity of the produced polypyrrole in a methanol solution obtained by mixing ferric dodecylbenzenesulfonate and pyrrole at a temperature of -70 ° C. with respect to dodecylbenzenesulfonate. is there. It can be seen that the conductivity sharply increases at 20% by weight or more.
FIG. 2 is a plot of the conductivity of polypyrrole obtained by dissolving 20% by weight of ferric dodecylbenzenesulfonate in methanol and reacting pyrrole with the amount of pyrrole added to dodecylbenzenesulfonic acid. (A) in the figure is the result of mixing ferric dodecylbenzenesulfonate and pyrrole at −70 ° C., stirring and polymerizing,
(B) is the result of mixing at the polymerization temperature. -30 ° C
The lower the mixing ratio, the higher the conductivity, and the amount of pyrrole added to ferric dodecylbenzene sulfonate was 3
It turns out that it becomes 60 S / cm or more at more than the vicinity of double molar. This value of the electrical conductivity coincides with the electrical conductivity of polypyrrole synthesized by the electrolytic polymerization method using the same electrolyte anion. Generally, in the polymerization reaction of pyrrole by the ferric salt, it is considered that 2 mol per 1 mol of pyrrole is used for coupling, and about 0.25 mol is used for doping. Therefore, the required pyrrole per mole of ferric salt is calculated to be 0.44 mole. The above results show that much higher pyrrole loading yields highly conductive polypyrrole. In FIG. 3, 20% by weight of ferric dodecylbenzenesulfonate was dissolved in methanol, and 2 wt.
The polypyrrole conductivity obtained by reacting twice the mole of pyrrole is plotted against the polymerization temperature. (A) in the figure shows ferric dodecylbenzenesulfonate and pyrrole at -70 ° C.
The results are obtained by mixing at a polymerization temperature with stirring, and (b) is the result of performing the polymerization at the polymerization temperature. It can be seen that the conductivity is higher when mixed at −30 ° C. or less, and the polymerization temperature becomes 40 S / cm or more below about 25 ° C. as a boundary.

Since the conductive polymer produced by the method of the present invention has high conductivity and excellent stability, it can be used as a solid electrolyte or electrode material of a capacitor, an antistatic material or an electromagnetic wave shielding material.

[0015]

Next, an embodiment of the present invention will be described.

Example 1 In three glass reaction vessels, the concentrations were 26.7%, 40% and 53.3% by weight.
75 g of a methanol solution of ferric dodecylbenzenesulfonate is added, 5 g of distilled water is added dropwise, and the mixture is stirred.
An oxidizing agent solution was prepared by cooling to 70 ° C. Next, 3.84 g, 5.76 G, and 7.67 g of pyrrole were dissolved in 16.16 g, 14.24 g, and 12.33 g of methanol, respectively, to prepare 20 g of a methanol solution of pyrrole. Each of these solutions was added dropwise to a ferric dodecylbenzenesulfonate solution cooled to -70 ° C, and the oxidizing agent concentration was 20% by weight, 30% by weight, and 40% by weight, respectively, and was 3 times the molar amount of the oxidizing agent. A solution containing pyrrole and 5% by weight of water was made. When these solutions were reacted at 0 ° C. for 2 hours, black polypyrrole was formed. This was filtered, washed with methanol, and dried at 60 ° C. for 30 minutes to obtain a conductive polypyrrole powder.
The conductivity was 10 S / cm or more in all cases as shown in FIG. 1 and had excellent characteristics as a conductive material.

(Comparative Example 1) In a glass reaction vessel, the concentration was 1
75 g of a 3.3% by weight methanolic solution of ferric dodecylbenzenesulfonate was added, 5 g of distilled water was added dropwise, and the mixture was cooled to -70 ° C with stirring to prepare an oxidizing agent solution. Next, 1.92 g of pyrrole was dissolved in 18.08 g of methanol, and the solution was added dropwise to an oxidizing solution at −70 ° C. to give an oxidant concentration of 10%.
A solution was prepared containing, by weight, 3 times the moles of pyrrole and 5% by weight water relative to the oxidizing agent. When this solution was reacted at 0 ° C. for 2 hours, black polypyrrole was formed. This was filtered, washed with methanol, and dried at 60 ° C. for 30 minutes to obtain a polypyrrole powder. Conductivity to 10 as shown in FIG. 1 ^- a ² S / cm, was extremely low.

Example 2 75 g of a methanol solution of ferric dodecylbenzenesensulfone having a concentration of 40% by weight was placed in six glass reaction vessels, 5 g of distilled water was added dropwise, and the mixture was cooled to -70 ° C. while stirring. As a result, an oxidant solution was prepared. Next, 20 g of a methanol solution containing 7.67 g of pyrrole,
20 g of a methanol solution containing 8.95 g of pyrrole,
20 g of a methanol solution containing 2.56 g of pyrrole, 1
20 g of a methanol solution containing 0.23 g of pyrrole, 1
20 g of methanol solution containing 2.8 g of pyrrole, 15
3. 20 g of a methanol solution containing 20 g of pyrrole and 20 g of pyrrole were added dropwise to the oxidizing agent solution kept at -70 ° C., respectively. Solutions containing 4.0, 5.0, 6.0, and 8.0 moles of pyrrole and 5% by weight water were made. When this solution was reacted at 0 ° C. for 2 hours, black polypyrrole was formed. This was separated by filtration, washed with methanol, and dried at 60 ° C. for 30 minutes to obtain conductive polypyrrole powder. As shown in FIG. 2A, the conductivity was all 50 S / cm or more, and the material had excellent characteristics as a conductive material.

(Comparative Example 2) 75 g of a methanol solution of ferric dodecylbenzenesulfone having a concentration of 40% by weight was placed in six glass reaction vessels, 5 g of distilled water was added dropwise, and the mixture was cooled to -70 ° C with stirring. Thus, an oxidizing agent solution was prepared. Next, 20 g of a methanol solution containing 1.02 g of pyrrole,
20 g of a methanol solution containing 1.28 g of pyrrole,
20 g of a methanol solution containing 2.56 g of pyrrole,
20 g of a methanol solution containing 3.84 g of pyrrole,
20 g of a methanol solution containing 5.11 g of pyrrole and 20 g of a methanol solution containing 6.39 g of pyrrole were each dropped into an oxidizing agent solution kept at -70 ° C. 0.4, 0.5,
Solutions were made containing 1.0, 1.5, 2.0 and 2.5 moles of pyrrole and 5% by weight water. When this solution was reacted at 0 ° C. for 2 hours, black polypyrrole was formed.
This was filtered off, washed with methanol, and further treated at 60 ° C. for 3 hours.
After drying for 0 minutes, a conductive polypyrrole powder was obtained. As shown in FIG. 2A, the conductivity was 40 S /
cm or less, which was low.

Example 3 75 g of a methanol solution of ferric dodecylbenzenesulfone (26.7% concentration) was placed in six glass reaction vessels, 5 g of distilled water was added dropwise, and the mixture was cooled to -70 ° C. while stirring. As a result, an oxidant solution was prepared. Next, 20 g of a methanol solution containing 3.84 g of pyrrole was added.
The solution was dropped into an oxidant solution maintained at 70 ° C., and the oxidant concentration was 20
A polymerization solution was prepared containing, by weight, 3 moles of pyrrole and 5% by weight of water relative to the oxidizing agent. This solution was cooled at -20 ° C,
Reaction at 10 ° C, 0 ° C, 10 ° C, 20 ° C, and 25 ° C for 2 hours produced black polypyrrole. This was filtered, washed with methanol, and dried at 60 ° C. for 30 minutes to obtain a conductive polypyrrole powder.
As shown in FIG. 3, the conductivity was all 30 S / cm or more, and had excellent characteristics as a conductive material.

(Comparative Example 3) The polymerization solution of Example 3 was reacted at 30 ° C, 40 ° C, and 50 ° C for 2 hours to produce black polypyrrole. This was filtered, washed with methanol, and dried at 60 ° C. for 30 minutes to obtain a conductive polypyrrole powder. As shown in FIG. 3, the conductivity was 30 S / cm or less, and was low.

Example 4 A glass reaction vessel having a concentration of 2
75 g of a methanol solution of 6.6% by weight of ferric dodecylbenzenesulfonate was added, 5 g of distilled water was added dropwise, and the mixture was cooled to -70 ° C with stirring to prepare an oxidizing agent solution. Next, 20 g of a methanol solution containing 5.53 g of pyrrole
Was added dropwise to the oxidizing agent solution kept at -70 ° C. to prepare a polymerization solution having an oxidizing agent concentration of 20% by weight and containing 3 mol of pyrrole and 5% by weight of water with respect to the oxidizing agent. When this solution was reacted at 0 ° C. for 2 hours, black polypyrrole was formed.
This was filtered off, washed with methanol, and further treated at 60 ° C. for 3 hours.
After drying for 0 minutes, a conductive polypyrrole powder was obtained. The conductivity was 30 S / cm or more, and had excellent properties as a conductive material.

Example 5 A reaction vessel made of glass having a concentration of 2
75 g of a methanol solution of 6.6% by weight of ferric butylnaphthalenesulfonate was added, 5 g of distilled water was added dropwise, and the mixture was cooled to −70 ° C. with stirring to prepare an oxidizing agent solution. Next, 20 g of a methanol solution containing 4.68 g of pyrrole
Was added dropwise to the oxidizing agent solution kept at -70 ° C. to prepare a polymerization solution having an oxidizing agent concentration of 20% by weight and containing 3 mol of pyrrole and 5% by weight of water with respect to the oxidizing agent. When this solution was reacted at 0 ° C. for 2 hours, black polypyrrole was formed.
This was filtered off, washed with methanol, and further treated at 60 ° C. for 3 hours.
After drying for 0 minutes, a conductive polypyrrole powder was obtained. The conductivity was 30 S / cm or more, and had excellent properties as a conductive material.

(Example 6) In a glass reaction vessel, the concentration was 2
75 g of a 6.7% by weight methanolic solution of ferric dodecylbenzenesulfonate was added, 5 g of distilled water was added dropwise, and the mixture was cooled to −70 ° C. with stirring to prepare an oxidizing agent solution. Next, 20 g of a methanol solution containing 4.59 g of N-methylpyrrole was dropped into the oxidizing agent solution kept at -70 ° C.
An oxidant concentration of 20% by weight and 3 moles of N-
A polymerization solution containing methylpyrrole and 5% by weight of water was prepared. When this solution was reacted at 0 ° C. for 2 hours, black polypyrrole was formed. This was filtered, washed with methanol, and dried at 60 ° C. for 30 minutes to obtain a conductive polypyrrole powder. The conductivity was 1 S / cm or more, and had excellent characteristics as a conductive material.

(Comparative Example 4) A glass reaction vessel having a concentration of 2
75 g of a methanol solution of 6.6% by weight of ferric dodecylbenzenesulfonate was added, 5 g of distilled water was added dropwise, and the mixture was cooled to -70 ° C with stirring to prepare an oxidizing agent solution. Next, 25 g of a methanol solution containing 3.84 g of pyrrole
Was added dropwise to the oxidizing agent solution kept at -70 ° C, and the solution immediately turned black and a block-like product was obtained. This was washed with methanol and dried at 60 ° C. for 30 minutes to obtain poropyrrole having a conductivity of 1 S / cm or less.

[0026]

As described above, according to the present invention, a conductive polymer having high conductivity can be obtained by a simple method, and the effect is great.

[Brief description of the drawings]

FIG. 1 is a graph showing the relationship between polypyrrole conductivity and oxidant concentration obtained in Example 1 and Comparative Example 1.

FIG. 2 is a graph showing the relationship between the electrical conductivity of polypyrrole obtained in Example 2 and Comparative Example 2 and the molar ratio of a monomer in a polymerization solution to an oxidizing agent.

FIG. 3 is a view showing the relationship between the conductivity and the polymerization temperature of polypyrrole obtained in Example 3 and Comparative Example 3.

Claims (4)

(57) [Claims] 1. A method for producing polypyrrole or a polypyrrole derivative, which comprises polymerizing a polymerization solution obtained by mixing an oxidizing agent having a sulfonic acid compound as an anion and an expensive transition metal as a cation with pyrrole or a derivative thereof at -30 ° C. or lower, A method for producing a conductive polymer, wherein a polymerization solution contains 2% by weight or more of water, an oxidizing agent concentration is 20% by weight or more, and a mixing molar ratio of a monomer to an oxidizing agent is 3 or more. 2. The method for producing a conductive polymer according to claim 1, wherein the polymerization temperature is 25 ° C. or lower. 3. The expensive transition metal which is a cation of the oxidizing agent is a ferric ion or a cupric ion.
A method for producing the conductive polymer according to the above. 4. The method for producing a conductive polymer according to claim 1, wherein the sulfonic acid compound which is an anion of the oxidizing agent is an aromatic sulfonic acid having an alkyl substituent.