JPH03250019A - Oxidative polymerization of pyrrole - Google Patents

Abstract

PURPOSE:To obtain a pyrrole polymer having high conductivity and good moldability with the aid of a small amount of a catalyst by using a process for polymerizing a pyrrole (derivative) through chemical oxidation in the presence of a solvent with the aid of an oxidizing agent catalyst, wherein the polymerization is performed in the presence of a basic compound. CONSTITUTION:A process for polymerizing a pyrrole or its derivative of formula I {wherein R<1> is H, alkyl, alkenyl, (substituted) phenyl or (substituted) aralkyl; and R<2> is H or a group of formula II [wherein R<3> is H, alkyl or (substituted) benzyl]}, e.g. pyrrole or 4-methylpyrrole-3-carboxylic acid, through chemical oxidation in the presence of a solvent with the aid of an oxidizing agent catalyst (e.g. a compound of formula III), wherein the polymerization is performed in the presence of a basic compound (e.g. pyridine). A polymer having high conductivity and good moldability can be obtained by using a small amount of the catalyst.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a method for producing conductive polymers. More specifically, the present invention relates to a method for producing virol or virol derivative polymers by chemical oxidative polymerization.

[Conventional technology]

Polymerization of conductive polypyrrole is usually carried out by electrolytic oxidative polymerization or chemical oxidative polymerization. A chemical polymerization method was reported in 1920.

[^, ^ngel i, C, Lutri: Gazzetta Himica Italiana (Gazz, Chis, Ital,
) 5--Ω- (1920) 128] This method is a method in which an oxidizing agent such as hydrogen peroxide, lead dioxide, or ferric chloride is added to a virol solution for polymerization. However, the polymer obtained by this method only has low conductivity, and in recent years, highly conductive virol powder has been obtained (R,!!).

Myers+J, EIectron Mater”
-[(2) 61-69 (1986), these methods required a large excess of catalyst over monomer.

On the other hand, attempts have been made to oxidatively polymerize pyrrole and thiophene using a small amount of catalyst, but the conductivity is still insufficient in this case.

J, ↑ayanagi, N, Choshima (P
olymer preprints.

Japan Vol, 38, 7 (1989) [
Problems to be Solved by the Invention] Pyrrole and pyrrole derivatives are oxidatively polymerized using a small amount of catalyst, and a polymer having high electrical conductivity and good moldability is obtained.

[Means for solving problems]

The present inventors conducted extensive studies to solve the above problems and completed the present invention.

That is, the present invention provides general formula (1)] where R1 is hydrogen, an alkyl group, an alkenyl group, a phenyl group that may have a substituent or an aralkyl group that may have a substituent, Rz is hydrogen or a group represented by -COOR3 (where R3 represents hydrogen, an alkyl group, a phenyl group that may have a substituent or a benzyl group that may have a substituent); A method of chemically oxidatively polymerizing the represented pyrrole or virol derivative using an oxidizing agent catalyst in the presence of a solvent, which is characterized in that the process is carried out by adding a basic compound.

In the above general formula (+), it is not necessary to limit the number of carbon atoms of any of the groups other than hydrogen in R1, R and R3, but preferably they have 1 to 20 carbon atoms.

In addition to pyrrole, the compounds of general formula (1) used in the present invention include 4-methylpyrrole-3-carboxylic acid, 4-phenylpyrrole-3-carboxylic acid, and 4-methylpyrrole-3-carboxylic acid.
Methyl 3-carboxylate, ethyl 4-methylpyrrole-3-carboxylate, hexyl 4-methylpyrrole-3-carboxylate, benzyl 4-methyl-3-carboxylate, 4-n-propylpyrrole-3-carboxylate methyl acid,
4-n-propyl, ethyl roll-3-carboxylate, methyl pyrrole-3-carboxylate, 3-methylpyrrole, etc. are used. Moreover, a mixture of these can also be used.

The solvents used in the present invention are as follows, and they can be selected either singly or as a mixture.

For example, diethyl ether, diisobutyl ether, n
-Aliphatic and cyclic ethers such as dibutyl ether, diisopropyl ether, dimethoxyethane, THF, and dioxane, alcohol M such as methanol, ethanol, and isopropyl alcohol, halogenated hydrocarbons such as ethylene chloride, chloroform, benzene, toluene, and xylene , aromatic hydrocarbons such as nitrobenzene, aliphatic hydrocarbons such as hexane and heptane, alicyclic hydrocarbons such as cyclohexane, ester groups such as ethyl acetate and butyl acetate, aliphatics such as methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone, Alicyclic ketones, nitromethane,
DMSO%DMF, acetonitrile, etc. Among these, acetonitrile is also preferred as a solvent. The amount of solvent is 2 to 3 for the pyrrole or virol derivative.
0 times capacity preferably 5~! Use 5 times the volume.

The oxidant-based catalyst used in the present invention is AlCl3C
uCl Ox. Pyrrole or pyrrole derivative 1
The amount of AlCl5 is 0-0.8 mol and the amount of CuCl is 0.1-0.8 mol, preferably A! C.I.
s O, 1-0.3 mol, Cu CI O, 1-0, 3
It is a mole.

The basic compound used in this chemical oxidative polymerization includes pyridine, triethylamine, 2.2°-bipyridine, pyrazine, etc., but pyridine is the most preferred, and the amount added is 0.000000000000000000000000 per mole 1 mole of pyrrole or pyrrole derivative.
The amount is 2 to 0.6 mol, preferably 0.3 to 0.5 mol.

The oxidation reaction is carried out by charging under nitrogen, stirring, and then substituting under oxygen.The reaction temperature is 0 to 50°C, preferably 15°C.
Run at ~20'C for 10-50 hours.

(Example) Next, the present invention will be explained in more detail with reference to Examples.
This does not limit the present invention in any way.

Example! 1.5 g (l 1 wmol) of aluminum chloride (AICIs) was added to dry acetonitrile 30H1.
) and chloride*(CuCI) 1.1g (11*5o
Dissolve 1.8 d (22 ml) of pyridine and then add 3.9 d (555 ml) of pyridine dropwise.
) was added dropwise, and after stirring for about 2 hours, IJII, ta, 2
The reaction was carried out under stirring at 0"C for 24 hours.

The resulting reaction mixture was poured into a methanol-hydrochloric acid solution, followed by repeated filtration and precipitation, washed with a methanol-hydrochloric acid solution, and finally with methanol, and dried to obtain a spongy black powder.

The elemental analysis results of the obtained polymer showed that C4,ttH2゜t
hN+, oac Io, tsO・, J6・The JR spectrum is shown in FIG. 1. When this polymer was measured with a scanning electron microscope, it was found to be fibrillar (see figure).

The resulting spongy black powder product was heated and press-molded, and the derivative was processed using the four-terminal method ("Polymer Experimental Science" 12,
Thermodynamic, electrical and optical properties P-218Van
De Pauw method (based on the Hong Do Pau method), it was 4.2 x 10" and 37 cm.

Note that this powder could be molded very easily during heat molding.

Example 2 A black powder was obtained by carrying out the reaction and post-treatment in exactly the same manner as in Example 1, except that the reaction temperature was 15°C. The electrical conductivity measured by the four-terminal method was 6.7 x I O' 37 cm.

Comparative Example The reaction and post-treatment were carried out in exactly the same manner as in Example 1, except that pyridine was not added, to obtain a black powder.

The elemental analysis results of the obtained polymer were Ca, sa H5
-16N+, @@CIl, □00. □ and its IR
The spectrum is shown in FIG. 2. When this polymer was measured using a scanning electron microscope, it was found that many spherical particles with a diameter of 1 to 4 μm had gathered together to form a lump.

(Figure 4).

The obtained black powder was difficult to mold using a hot press, but the conductivity of the molded product was approximately 10-"37 using the two-terminal method.
It was cm.

[Effects of the Invention] In the oxidative polymerization method of the present invention, polymerization proceeds with a small amount of catalyst, and the resulting polymer incorporates a portion of the catalyst as a dopant, so a polymer with high electrical conductivity can be obtained. Furthermore, the obtained polymer has excellent moldability.

Polymers with these characteristics are not only useful as antistatic materials, electromagnetic shielding materials, and electrode materials for primary and secondary batteries, but also can be used in electronic devices such as bonding elements and switching elements. Conceivable.

[Brief explanation of drawings]

FIG. 1 shows the IR spectrum of the polymer obtained in Example 1 of the present invention, FIG. 2 shows the IR spectrum of the polymer obtained in the comparative example, and FIG. 3 shows the IR spectrum of the polymer obtained in Example 1 of the present invention. The crystal structure of the polymer obtained by scanning electron microscopy is shown below. Fourth
The figure shows the crystal structure of the polymer obtained in the comparative example as measured by a scanning electron microscope.

Claims (3)

[Claims] (1) General formula ▲ Numerical formula, chemical formula, table, etc. ▼ (In the formula, R^1 is hydrogen, an alkyl group, an alkenyl group, a phenyl group that may have a substituent, or a substituent. Aralkyl group, R^2 is hydrogen or -COOR
A group represented by ^3 (where R^3 represents hydrogen, an alkyl group, a phenyl group which may have a substituent, or a benzyl group which may have a substituent). ] A method of chemically oxidatively polymerizing pyrrole or a pyrrole derivative represented by the following with an oxidizing agent-based catalyst in the presence of a solvent, characterized in that the method is carried out by adding a basic compound. (2) The method according to claim 1, wherein the oxidizing agent system is AlCl_3-CuCl-O_2. (3) The method according to claim 1 or 2, wherein the basic compound is pyridine.