JPH0339324A - Production of polypyrrole - Google Patents

Abstract

PURPOSE:To readily obtain a polypyrrole having high conductivity by polymerizing pyrrole in the presence of manganese dioxide and an acid. CONSTITUTION:Pyrrole is polymerized in the presence of manganese dioxide and an acid (e.g. hydrochloric acid, formic acid, benzenesulfonic acid or phosphoric acid) to provide the aimed polymer.

Description

DETAILED DESCRIPTION OF THE INVENTION (Objects of the Invention) The present invention relates to a novel method for producing polypyrrole.

(Conventional technique tIR) A method for obtaining polypyrrole is to electrochemically anodize a pyrrole monomer in the presence of a suitable supporting electrolyte;
A method of chemically treating pyrrole monomer with an oxidizing agent is used.

Polypyrrole obtained by an electrochemical method is a polymer with high electrical conductivity, but a conductive substrate, that is, an electrode is an essential condition.

In contrast, chemical methods can produce polypyrrole with extremely simple operations, but the resulting polypyrrole generally has low conductivity. Polypyrrole with high conductivity can be produced by completing the oxidation reaction in a relatively short time at low temperature using
A method was proposed (Japanese Patent Application Laid-Open No. 63-284819).
According to the inventor's additional tests, this method yields 50S/cL11
It is possible to obtain polypyrrole with a degree of high conductivity.

However, the polypyrrole obtained by this method has chlorine ions acting as a dopant, and when this is used, for example, as an electrical element substrate, the chlorine ions may corrode the electrical element substrate, which is undesirable. affect.

Chemical oxidative polymerization methods for pyrrole that contain other 7ions as dopants include, for example, methods using ammonium persulfate as an oxidizing agent and methods using a system of hydrogen peroxide and an acid, but ammonium persulfate has a low oxidation potential. It is difficult to obtain polypyrrole with high electrical conductivity because even polypyrrole with high conductivity is oxidized. For reasons that are unclear, polypyrrole with high electrical conductivity cannot be obtained even in systems using an oxidizing agent using a combination of hydrogen peroxide and an acid such as sulfuric acid.

(Problems to be Solved by the Invention) An object of the present invention is to obtain polypyrrole by chemical oxidative polymerization in which various anions can be selected as dopants and which has high electrical conductivity.

(Means for Solving the Problems) As a result of intensive research, the present inventors have discovered a method for producing polypyrrole that can achieve the above object.

That is, this is a method for producing polypyrrole by polymerizing pyrrole using a combination of manganese dioxide and an acid.

Since manganese dioxide is generally insoluble in water, alcohol, and other organic solvents used in the chemical oxidative polymerization of pyrrole, its use as an oxidizing agent for polypyrrole has not been considered at all. However, according to experiments conducted by the present inventors, it was found that even insoluble manganese dioxide can be used in combination with an acid to oxidatively polymerize pyrrole. Moreover, it was found that the conductor produced by changing the amount of acid and the amount of pyrrole relative to manganese dioxide was polypyrrole alone or a composite of polypyrrole and manganese dioxide, leading to the completion of the present invention. .

Next, the manufacturing method of the present invention will be explained in more detail.

Add a predetermined amount of manganese dioxide to a suitable solvent and stir. After adding a predetermined amount of acid and pyrrole monomer to this,
Stir for a certain period of time. The obtained black precipitate is filtered off, washed with water and alcohol, and then dried.

Manganese dioxide used in the present invention can be used regardless of its manufacturing method or crystal form. That is, an electrolytic method, a chemical method, or a naturally produced product can be used, and both crystals and α-1β-γ-type can be used.

Examples of acids include mineral acids such as hydrochloric acid, nitric acid, and sulfuric acid, carboxylic acids such as formic acid, acetic acid, and propionic acid, organic sulfonic acids such as benzenesulfonic acid and paratoluenesulfonic acid, phosphoric acid, tetrafluoroboric acid, and hexafluoroboric acid. Inorganic acids such as phosphoric acid and perchloric acid can be widely used. These acid anions are thought to function as dopants during the production of polypyrrole, and the fact that such a wide range of acids can be used means that a wide range of dopants can be selected.

Examples of solvents include water, monohydric alcohols such as methanol, ethanol, and propanol, aromatic hydrocarbons such as benzene, toluene, and xylene, and pyrrole such as acetonitrile, propylene carbonate, nomethyl triamamide, and acetone. A wide variety of solvents can be used for polymerization.

When only polypyrrole is produced, an excess of acid over manganese dioxide is always used. The amount of acid used varies depending on the type of acid used, but it is generally used in an amount equal to or more than the number of moles of manganese dioxide. Further, it is preferable that the amount of pyrrole used is equal to or more than the number of moles of manganese dioxide.

To produce polypyrrole-mandioxide complex,
The amount of acid should be smaller than the number of moles of manganese dioxide in terms of moles, but the amount of acid should be adjusted according to the desired composite ratio and cannot be particularly stipulated. The order of addition is not particularly strict, and there is no problem in adding them in any order. The reaction temperature should be higher than the melting point, preferably as low as possible.

(Examples) Next, the manufacturing method of the present invention will be specifically explained using Examples, but the present invention is not limited to these Examples.

[To 501111 water containing 1.0 g of upper pyrrole, 4. Og was added and stirred to dissolve. Stir this solution and keep it at 0℃,
added. After stirring for 10 minutes and reacting, it was filtered, washed twice with water and ethanol, and then incubated in a vacuum for 20 minutes.
After drying for hours, 0.6 g of dark green powdered polypyrrole was obtained. X-ray diffraction revealed that this powder did not contain manganese dioxide. This powder was molded at a pressure of it/cm2 to a diameter of 13III@ and a thickness of 1. A circular pellet of OLIm was obtained.

Electrodes were attached to both sides using silver paste and platinum wire, the resistance was measured, and the conductivity was calculated to be 51S/C16.

Example 2 The reaction was carried out in the same manner as in Example 1 except that 1.0 g of manganese dioxide was added. As a result, 1. A black polypyrrole powder of Og was obtained. The conductivity of the pellet produced in the same manner as in Example 1 was 48 S/cm. No manganese dioxide peak was observed in this powder by X-ray diffraction.

Water 501111 containing 3.2 g of 98% sulfuric acid was kept at 0°C and stirred with 1.0 g of pyrrole and 1.0 g of manganese dioxide.
were added sequentially and allowed to react for 20 minutes. Thereafter, after processing in the same manner as in Example 1, 1.1 g of black polypyrrole powder was obtained. A pellet was made from this powder in the same manner as in Example 1, and the conductivity was measured to be 38 S/cm.

No manganese dioxide peak was observed in this powder by Xi diffraction.

5.0 g of acetic acid was added to methanol 501111 containing 1.0 g of pyrrole and kept at 0° C. while stirring. 0.7 g of mantane dioxide was added to this solution and reacted for 25 minutes.

The viable precipitate was filtered out, washed twice with water and methanol, and vacuum dried to yield 0.72 g of black polypyrrole powder.
A pellet was then made in exactly the same manner as in Example 1, and the conductivity was measured to be 71 S/c.

Aqueous solution containing heptammonium 3,4Fi persulfate 50-
1. Keep pyrrole at 0°C and stir. Og was added dropwise.

A black precipitate formed instantly, and after continued stirring for 25 minutes, the precipitate was filtered off to obtain a 0.78 polypyrrole powder. Post-treatment and conductivity measurements were performed in the same manner as in Example 4, and the result was 6, OXI O'-2S/an.

Vertical hydrogen peroxide 1. 50ml of aqueous solution containing Og, 2.2g of sulfuric acid
1.0 g of pyrrole was added while stirring while keeping f at 5°C. After stirring for 20 minutes, the black precipitate that grew was washed and dried in exactly the same manner as in Example 1, resulting in 0.6
g of black polypyrrole powder was obtained. Example 1
3.8X1 molded in exactly the same manner and measured for conductivity
It was 0-'S/co+.

X-bi 1 [0.6g of para-toluenesulfonic acid, man dioxide]
The reaction was carried out in exactly the same manner as in Example 1, except that the amount of powder was changed to 1.3 g, and 1.2 g of black powder was obtained. The conductivity of this material was measured in exactly the same manner as in Example 1. Result 1: OXI O=S/a
It was 111.

Added 1.6 g of paratoluene sulfone to 50 + a1 of water containing 0.5 g of buried pyrrole, added 1.3 g of mandioxide, and stirred while maintaining the temperature at 5°C. Reacted for 10 minutes. After that, it was filtered and diluted with water and ethanol.
After washing twice and drying in vacuum for 20 hours, 1.1 g of black powder was obtained. This powder was molded in the same manner as in Example 1, and its conductivity was measured to be 1.0×10'S/cm.

X-ray diffraction revealed that this powder contained manganese dioxide, a raw material. In addition, analysis using a scanning electron microscope revealed that polypyrrole was attached to the manganese dioxide particles. The X-ray diffraction pattern is shown in FIG.

Example 6 except that 1.2 g of para-toluenesulfonic acid was used.
In exactly the same manner as above, 1.3 g of powder having a conductivity of 2 S/cm was obtained. X-ray diffraction revealed that this powder contained a trace amount of manganese dioxide.

Figure 1 shows the diffraction pattern.

Example E A black powder with a conductivity of 108/cm was prepared in the same manner as in Example 6, except that 2.0 g of para-toluenesulfonic acid was used.
8g was obtained. Analysis using a scanning electron microscope revealed that this powder was a polypyrrole-mandioxide complex. FIG. 1 shows an X-ray diffraction pattern showing the presence of manganese dioxide.

The manganese dioxide used in the example was made into a pellet by the method of the example, and the conductivity was measured at 1.60 x 10''S.
/aI6. The X#X diffraction pattern is shown in FIG.

and (salmon ±) The conductivity was 1,3X in the same manner as in Example 6 except that the acid used was 1.0g of sulfuric acid and 0.3g of pyrrole
1.1 g of a polypyrrole-manganese dioxide complex of 10' S/c nitrate was obtained.

East IL Kamiyu - The conductivity was determined in the same manner as in Example 6, except that the acid used was 0.4Fl of tetrafluoroboric acid and the solvent was methanol.
, 1.2 g of a polypyrrole-manganese dioxide complex of 2×10-'S/c theory was obtained.

X-Tomi Myoyuzu - The acid used is perchlorine @1.9g, and the amount of pyrrole is 0.1
1.2 g of a polypyrrole-mandioxide composite having a conductivity of 3.8×10 −2 S/am was obtained in the same manner as in Example 6, except that the reaction time was 3 minutes.

(Effect of the invention) In the method for producing polypyrrole, polypyrrole with high conductivity can be easily produced by chemically oxidizing and polymerizing pyrrole using manganese dioxide and acid as a completely new oxidizing agent. was completed.

Furthermore, by adjusting the amount of acid and the amount of pyrrole, it was possible to easily produce a polyvia-manganese dioxide composite. The composite produced in this way has a much higher conductivity than manganese dioxide, so it can be used to improve the performance of electrical devices that use manganese dioxide, such as battery materials and capacitor materials.

[Brief explanation of drawings]

FIG. 1 shows the X#i diffraction pattern of the polypyrrole-manganese dioxide composite obtained by the method of the present invention and the XM diffraction pattern of manganese dioxide for comparison.

Claims (1)

[Claims] 1. A method for producing polypyrrole, which comprises polymerizing pyrrole in the presence of manganese dioxide and an acid.