JPH01230628A - Production of thiophene polymer - Google Patents

Abstract

PURPOSE:To safely and easily obtain the title high-MW polymer without using any catalyst by reacting a thiophene compound with an alkali metal compound in an organic solvent in the absence of water and further continuing the reaction in an oxygen atmosphere. CONSTITUTION:A thiophene compound of the formula (wherein R<1-2> are each H or a halogen) is anionically reacted with 0.5-5.0 equivalents, per equivalent of the compound, of an alkali metal compound of the formula R<3>.M [wherein R<3> is an alkyl or an (alkyl-substituted) phenyl, and M is an alkali metal] in the absence of water in a water-free organic solvent such as dried ethyl ether or tetrahydrofuran in an inert gas atmosphere at low temperature, desirably, -70-10 deg.C to obtain an anionic intermediate. This intermediate is further reacted in an oxygen atmosphere.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a method for producing a thiophene-based polymer.

[Conventional technology]

Recently, research has been actively conducted on conductive materials made of organic polymers such as polyacetylene and polypyrrole, and polythiophene is one of them.

Among polythiophenes, linear poly(2,5-thiophene), in which the 2- and 5-positions of thiophene are regularly bonded, has excellent moldability and thermal stability, and can easily be made into a conductive material by adding an electron acceptor. It has the characteristics of using a nickel compound as a catalyst and 2.5-
It is produced by reacting dihalogenated thiophene with magnesium. (Tokuko Sho 58-24446
Publication No.).

However, the above-mentioned production method uses metallic magnesium as a Grignard reagent, which is dangerous, and uses a nickel compound as a catalyst, which is cumbersome to operate.

[Problem that the invention seeks to solve]

An object of the present invention is to provide a method by which thiophene polymers can be produced safely and easily.

[Means for solving problems]

Examples of the organic solvent used in the present invention include ether solvents such as ethyl ether, methyl phenyl ether, and tetrahydrofuran, benzene, toluene, ethyl acetate, hexane, cyclohexane, and petroleum ether, Ether solvents having excellent reactivity with the indicated alkali metal compounds are preferably used.

If the organic solvent contains water, the alkali metal compound represented by the general formula (Ill) reacts with water and loses reactivity, so the organic solvent is used in a state substantially free of water.

The thiophene compound used in the present invention has the general formula (I)
In the formula, R1 and R+ represent a hydrogen atom or a halogen atom, and R1 and R' may be the same or different. Incidentally, examples of the halogen atom include fluorine, chlorine, bromine and iodine, with bromine and iodine being preferred.

Examples of the above-mentioned thiophene compounds include thiophene, 2-bromothiophene, 2-iodinated thiophene, 2.
Examples include 5-dibromothiophene.

The alkali metal compound used in the present invention is represented by the general formula Ql) R''-M...where R' represents an alkyl group, a phenyl group, or an alkyl-substituted phenyl group, and M represents an alkali metal. The above-mentioned furkyl group preferably has 10 or less carbon atoms, such as methyl, ethyl, n-propyl, 1
Examples include groups such as so-propyl, n-butyl, 5ec-butyl, n-pentyl, n-hexyl, and more preferably ethyl, n-propyl, 1so-propyl, n-butyl and 1so-butyl groups, The alkyl-substituted phenyl group is preferably a phenyl group substituted with an alkyl group having 10 or less carbon atoms, such as methylphenyl, dimethyl 2-enyl, ethylphenyl, and the like. Further, examples of the alkali metal include lithium, sodium, potassium, etc., and n-butyllithium is preferable as the alkali metal compound.

In the present invention 1ζ, the thiophene compound (It) and the alkali metal compound (U) are first reacted in an organic solvent in the substantial absence of water.

The thiophene compound (I) and the alkali metal compound undergo an anionization reaction to form an anion intermediate, and this intermediate undergoes a polymerization reaction to become a thiophene polymer. After the anionization reaction has progressed as much as possible, the polymerization reaction takes place. It is preferable to carry out the polymerization in an oxygen atmosphere after the completion of the anionization reaction, since the yield will be higher and a polymer with a higher molecular weight will be obtained.

Incidentally, the above anionization reaction is preferably carried out at a low temperature, more preferably from -70°C to 10°C. Further, the polymerization reaction is preferably carried out at -10°C to 50°C. Although the anionization reaction may be carried out in any atmosphere, it is preferably carried out in an inert gas atmosphere, more preferably in a nitrogen atmosphere, so that side reactions do not proceed.

Thiophene compound (I) and alkali metal compound (■)
When the amount of addition of the alkali metal compound (Ill) decreases, the amount of anions produced decreases, making it difficult to obtain a high molecular weight thiophene polymer; This makes it easier to obtain by-products and low-molecular-weight thiophene-based polymers, and since alkali metal compounds (1) tend to react with water and become deactivated, thiophene-based compounds (I) (Iζ) and alkali metal compounds (R) is preferably added in an amount of α5 to 5.0 equivalents, more preferably Lθ to 3.0 equivalents.

〔Effect of the invention〕

The method for producing the thiophene polymer of the present invention is as described above, and a high molecular weight thiophene polymer can be obtained safely and easily without using a catalyst.

The obtained thiophene-based polymer is soluble in organic solvents and can be easily molded. In addition, thiophene-based polymer molded bodies have an affinity for electron acceptors such as iodine, sulfur dioxide, sulfuric acid, tetracyanoquinodimethane, and tetracyanoethylene, and strongly adsorb these electron acceptors. By doing so, an excellent organic polymer semiconductor can be easily obtained.

〔Example〕

Next, the present invention will be explained in detail.

Example 1 2-bromothiophene 6.749 (4
34 ml of a hexane solution of n-butyllithium (L 4 s mol//) while stirring at 0°C in a nitrogen stream.
(5α3 mmol of n-butyllithium) was added dropwise over 30 minutes, and after the addition, the reaction was allowed to proceed for 3 hours. The solution was reacted for 2 hours under an oxygen atmosphere to obtain a black-red reaction solution. Add tetrahydrofuran and toluene to the resulting reaction solution,
After washing with water, the water was removed with anhydrous sodium sulfate, and the solvent was removed with a rotary evaporator to obtain a black product. The obtained product was reprecipitated with tetrahydrofuran and hexane to obtain a black solid L77F.

The obtained black powder was soluble in tetrahydrofuran and dimethyl sulfoxide, and its molecular weight was about 2,000 when measured by GPC spectrum. (Polystyrene equivalent) Even when the black solid was exposed to air at 25° C. for one month, there was no change in the GPC spectrum and infrared absorption spectrum.

Table 1 also shows the elemental analysis values of the black solid.

The obtained black solid was fed to an infrared molder and heated at 2400
When molded at a pressure of Ji/C- and the electrical conductivity of the obtained molded body was measured, it was 4.6 x 10-"S/am at 25°C.
Met. The obtained molded product was exposed to iodine vapor at 80° C. for 3 days to obtain a molded product doped with 185% iodine. The electrical conductivity of this molded body is Z at 25°C.
It's 9 X 10' S/am.

Example 2 Hexane solution of 1-butyllithium (L48 mol//
) 62 ml (M-butyllithium 9 L 7
A black solid of L68F was obtained in the same manner as in Example 1, except that 1 mmol) was added dropwise over 60 minutes. When the obtained black powder was measured by GPC spectrum, the molecular weight was about 2000. (Polystyrene equivalent) Elemental analysis values are shown in Table 1. In addition, when the electrical conductivity was measured in 9 directions as in Example 1, it was 25
℃ at 3. The resulting molded product was exposed to iodine vapor at 80°C for 3 days to obtain a molded product doped with 160mff1% of iodine.The electrical conductivity of this molded product was 5°4 x 10' at 25°C
It was S/ai.

Example 3 Thiophene 3.36g (40.0mm
ol) and 70 d of dry ethyl ether, a hexane solution of 2-butyllithium (L 48 mat/z) 314- was added with stirring at θ°C in a nitrogen stream.
The mixture was added dropwise over 0 minutes, and after the addition, the reaction was continued for 1 hour to obtain a deep yellow reaction solution. Next, oxygen was injected into the flask, and the resulting reaction solution was reacted for 1 hour in an oxygen atmosphere to obtain a black-red reaction solution. The resulting reaction solution was treated in the same manner as in Example 1 to obtain a black powder of L96. The molecular weight of the obtained black powder according to the GPC spectrum is about 30.
It was 00. (Polystyrene equivalent) Elemental analysis values are shown in Table 1. A molded body was obtained from the obtained black powder in the same manner as in Example 1, and its electrical conductivity was measured to be 8° OX 10-145/am at 25°C. The obtained molded product was exposed to iodine vapor at 80° C. for 3 days to obtain a molded product doped with 230 M% of iodine. The electrical conductivity of this molded body at 25°C is 2. OX 10'S/
It was am.

Example 4 Hexane solution of n-butyllithium (L48mat//
) A black powder of ziip was obtained in the same manner as in Example 3 except that 59.4 d was added dropwise, and the molecular weight was about 3000 as measured by GPC spectrum. The elemental analysis values (in terms of pristyrene) are shown in Table 1. A molded body was obtained from the obtained black powder in the same manner as in Example 1, and its electrical conductivity was measured to be 7.5X at 25°C.
10-"S/C11.The obtained molded body was
Exposure to iodine vapor for 3 days at ℃ and 200ff of iodine
A molded body doped with 1% ij was obtained. The electrical conductivity of the obtained molded body was 6.5 x 10-ゝS/3 at 25°C.

Example 5 2,5-dibromothiophene 5.38 in a Yotsuro flask
9 (22.3 mmol) and dry ethyl ether 50-
A hexane solution of n-butyllithium (L48 mol/l) 18 was supplied while stirring at θ°C in a nitrogen stream.
d (n-butyllithium 26.6 mmol) at 1
The mixture was added dropwise over 5 minutes, and after the addition, the reaction was continued for 60 minutes to obtain a deep yellow reaction solution.

The temperature of the obtained reaction solution was raised to 25° C. in a water bath, and after reacting for 2 hours, oxygen was injected and the reaction was continued for 5 hours in an oxygen atmosphere to obtain a black-red reaction solution. Tetrahydrofuran and toluene were added to the resulting reaction solution, washed with water, water was removed with anhydrous sodium sulfate, and the solvent was removed using a rotary evaporator to obtain a black product. The obtained product was reprecipitated with tetrahydrofuran and hexane to obtain a black powder of L35F.

When the molecular weight was measured, the molecular weight was about 5,000.

(Polystyrene equivalent) Even when the black powder was exposed to air at 25° C. for one month, there was no change in the GPC spectrum and infrared absorption spectrum.

Further, the elemental analysis values of the black powder are shown in Table 1.

The obtained black powder was fed to an infrared molding machine and heated at 2400 m
The electrical conductivity of the molded product obtained by molding at a pressure of k/Crt was measured and was found to be a2×10 5 /am at 25°C. The obtained molded product was exposed to iodine vapor at 25° C. for 30 days to obtain a molded product doped with 232% by weight of iodine. The electrical conductivity of this molded body is L19X10' at 25°C.
It was S^.

Example 6 25-dibromothiophene 5, 38 in a Yotsuro flask
f (213 mmol) and dry ethyl ether 50-
A hexane solution of n-butyllithium (L48 mol) 18+R was supplied while stirring at o℃ in a nitrogen stream.
1 (n-butyllithium 26.6 mmol) was added dropwise over 40 minutes, and after the addition, the reaction was continued for 60 minutes to obtain a deep yellow reaction solution. Subsequently, oxygen was introduced and the mixture was reacted for 60 minutes in an oxygen atmosphere to obtain a black-red reaction solution. The resulting solution was treated in the same manner as in Example 5 to obtain a black powder of Li3N. The molecular weight of the obtained black powder according to the GPC spectrum is about 3000 (in terms of polystyrene).
The elemental analysis values are shown in Table 1.

In addition, a molded body was obtained in the same manner as in Example 5, and the electrical conductivity was measured to be 4.3 x 10''S/am.
Met. When the obtained compact was exposed to iodine vapor at 25°C for 30 days, it was found to be doped with 101% by weight of iodine, and the electrical conductivity was 8.73 x 10-' at 25°C.
It was S/3.

Example 7 A black powder of α469 was obtained in the same manner as in Example 6 except that all reactions were conducted in an oxygen atmosphere. The molecular weight of the obtained black powder according to the GPC spectrum is about 2000.
Met. (Polystyrene equivalent) Also, the elemental analysis value is the first
Shown in a table.

Example 8 25-dibromothiophene 5.381 in a Yotsuro flask
(3 mmol of 2SL) and 50 d of dry ethyl ether were supplied, and while stirring at θ°C in a nitrogen stream, a hexane solution of n-butyllithium (L48 mol/liter 33.1+n
/ (n-butyl lithium 48.9 mmol) was added dropwise over 15 minutes, and after reacting for 2 hours, oxygen was introduced and the reaction was carried out for 1 hour in an oxygen atmosphere to obtain a black-red reaction solution. The reaction solution was treated as in Example 1 and L
A black powder of 27 Da was obtained. The molecular weight of the obtained black powder as determined by GPC spectrum was about 3000. The elemental analysis values (in terms of polystyrene) are shown in Table 1. A molded body was obtained from the obtained black powder in the same manner as in Example 5, and the electrical conductivity was measured to be 1 m 4 × at 25°C.
It was 10”S/am.

Comparative Example 2-methylthiophene L939 (1
9.7 mmol) and 50 d of dry ethyl ether were supplied, and while stirring at 0° C. in a nitrogen stream, a hexane solution of n-butyllithium (L 48 moVt) was added to 16 me (L 48 moVt).
n-butyllithium (23.6 mmol) was added dropwise over 15 minutes, and after the addition, the reaction was continued for 60 minutes to obtain a yellow reaction solution. Subsequently, oxygen was introduced, and the mixture was reacted for 60 minutes in an oxygen atmosphere to obtain a black-red reaction liquid. The resulting solution was treated in the same manner as in Example 1 to obtain a brown powder of α491.

The molecular weight of the obtained powder according to the GPC spectrum is about 10
It was 00. (Polystyrene equivalent) 1st
table

Claims (1)

[Claims] 1. In an organic solvent, substantially in the absence of water, the general formula (
There are thiophene compounds represented by I) and ▲mathematical formulas, chemical formulas, tables, etc.▼...(I) (In the formula, R^1 and R^2 represent hydrogen atoms or halogen atoms, and R^1 and R ^2 may be the same or different.) Alkali metal compound R^1 represented by general formula (II)
M...(II) (In the formula, R^1 is an alkyl group, a phenyl group, or an alkyl-substituted phenyl group, and M is an alkali metal.) is reacted and then further reacted in an oxygen atmosphere. A method for producing a thiophene-based polymer.