JPH0331735B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a novel polymer having electrical conductivity, and more particularly to a method for producing a carbon diselenide polymer.

[Conventional technology]

BACKGROUND ART Conventionally, conductive polymer materials having a conjugated system formed by carbon-carbon bonds in a polymer skeleton have been synthesized. Examples of these include polyacetylene, polypyrrole, polyphenylene, polyphenylene vinylene, and the like. However, some polymers that contain chalcogenide atoms in their skeletons and do not appear to form a conjugated system include polyphenylene sulfide, polyvinylene sulfide, polyphenylene selenide, and polyvinylene selenide. Some materials, such as nido, that exhibit semiconductivity or conductivity through doping are also known. Among them, polymers using carbon diselenide as a starting material are extremely simple polymers made of selenium and carbon, and are thought to have potential as conductive polymer materials.

Conventionally, carbon diselenide polymers have a pressure of about 5,000 atm.
It is known that synthesis can be performed at temperatures of 100 to 200°C (Y. Okamoto and PSWojciecnowski, J.
chem.Soc., chem.Commun., 386, 1982, or H. Kobayasi et al.Chem.Let., 1407, 1983).
However, this method requires synthesis under high pressure of 5,000 atmospheres, so it cannot be said to be an easy method for synthesizing polymers.

[Problem that the invention seeks to solve]

The above-mentioned conventional high-pressure method for producing carbon diselenide polymers is carried out under extremely harsh conditions, making synthesis difficult and having poor workability. The present invention relates to a method for simplifying the manufacturing method and improving workability by synthesizing a carbon diselenide polymer under one atmospheric pressure and at a temperature below room temperature.

[Structure of the invention]

In order to achieve the above-mentioned object, as a result of intensive study on a method for synthesizing carbon diselenide, a method for producing carbon diselenide was discovered that can be produced at room temperature and under one atmospheric pressure. Furthermore, the polymer obtained by this method can be used without doping treatment.
It was found that it has an electrical conductivity of about 10 ^-8 S/cm, and that it shows an electrical conductivity of 10 ^-3 to ^{10 -2} S/cm by doping. The present invention provides such a diselenated carbon polymer,
This relates to a method of synthesis at a temperature near room temperature and under one atmospheric pressure. This method will be explained in detail below.

The present invention relates to a method characterized in that carbon diselenide is polymerized using an anionic catalyst in a suitable solvent. The appropriate solvent here may be a polar solvent such as dimethyl sulfoxide, dimethylformamide, tetrahydrofuran, N-methylpyrrolidone, or chloroform, or a nonpolar solvent such as benzene or toluene, but preferably the polymer is a polar solvent. A polar solvent is used that is soluble in the polymer and allows the polymerization reaction to proceed smoothly.

The polymerization temperature is such that the boiling point of carbon diselenide is 125 to 126
℃, it is desirable to keep the temperature as low as possible. Polymerization using this method is possible even at temperatures above the boiling point of carbon diselenide (126° C.), and in this case it is necessary to carry out the polymerization under pressure to prevent carbon diselenide from escaping from the solvent. However, unlike conventional methods, pressurization of several thousand atmospheres is not necessary, and the present invention, which uses a catalyst, allows polymerization under pressure of 10 atmospheres or less.

Further, since the melting point of carbon diselenide is -46°C, the appropriate temperature for polymerizing carbon diselenide in the method according to the present invention is preferably -40°C or higher. When polymerization is carried out at low temperatures, it is of course necessary to use a solvent whose melting point is below the polymerization temperature. For example, when tetrahydrofuran, which is a solvent with a low melting point, is used as a solvent, polymerization can be carried out at around -40°C.

As the catalyst used in the present invention, anionic catalysts are used, but preferably alkali metals,
Alkoxide alkali metals, alkyl alkali metals, alkyl alkaline earth metals, etc. are preferably used. More preferably, alkali metals such as sodium, lithium, and potassium are used.
These alkali metal catalysts can be used as they are mixed into a solvent, but they can also be used mixed into a solvent as a dispersion in paraffin, a complex with naphthalene or the like, or an inclusion compound with crown ether. A predetermined amount of these catalysts may be mixed in advance in the solvent, but it is also possible to carry out the polymerization while sequentially adding the catalyst dropwise as the polymerization reaction progresses. The concentration of catalyst in the solvent is usually
Concentration range from 0.001 to 3.0 mol/, preferably from 0.05 to
The reaction is carried out in the range of 1.0 mol/.

Further, the concentration of carbon diselenide, which is a monomer, is not particularly limited, but it is usually used at a concentration of 0.1 to 10 mol/.

There are no particular restrictions on the reaction time, but in order to achieve the objectives of the present invention with a high yield, it is preferably 3 hours or more, depending on the type of solvent and catalyst or the reaction temperature. In order to increase the yield, it is necessary to lengthen the reaction time in the low temperature range.

During the reaction, it is preferable to stir as vigorously as possible. Particularly when powders of metal sodium, lithium, etc. are used as a catalyst, it is important for more uniform dispersion.

In the manner described above, a black powdery polymer can be obtained. The conductivity of this polymer itself is approximately 10 ^-8
S/cm. To further improve the conductivity, the polymer may be doped with an electron-donating or electron-accepting substance. Polymerization methods include doping by exposing the polymer to a dopant gas atmosphere, doping by immersing the polymer in a dopant solution, electrochemical doping, and ion implantation. There are methods such as a method in which a dopant is mixed into a polymer solution, and then the polymer is molded.

Since the polymer synthesized according to the present invention is a unique polymer that dissolves in a polar solvent, it is possible to mix a dopant into the polymer solution. Since conventionally known conductive polymers such as polyacetylene, polypyrrole, polythiophene, and polyparaphenylene are infusible and insoluble, doping by this method is impossible. This method of mixing a dopant into a polymer solution has the advantage that the doping time can be shortened compared to other doping methods, and the polymer can be doped uniformly. Of course, it is possible to dope the carbon diselenide polymer by any other doping method.

Hereinafter, the present invention will be explained in more detail based on Examples.

[Example] Example 1 Carbon diselenide (monomer, CSe ₂ ) 2.0 was dehydrated using Molecular Sieve 5A while purging a 50 c.c. three-necked flask (reactor) with nitrogen gas.
ml (5.3gr) and N-methyl-2-pyrrolidone (solvent), which was also dehydrated with Molecular Sieve 5A.
Add 10ml. Next, a catalyst solution prepared by dissolving 0.25g of Na-naphthalene in 10ml of dehydrated N-methyl-2-pyrrolidone was added to the solution using a dropping funnel.
Nitrogen temperature (20℃) while dropping at a rate of 0.2ml/min
Polymerization was then carried out with stirring for 15 hours. A reddish brown reaction solution containing some precipitate was obtained. After gradually adding 30 ml of water to this, the pH was adjusted to 3 with a 10% aqueous hydrochloric acid solution, and a blackish brown precipitate was deposited. After over-separating this precipitate, washing with water is repeated several times until the washing solution becomes neutral.
The washed polymer was vacuum dried under nitrogen temperature for 6 hours.
5.0 gr of dark brown powder was obtained. The blackish brown powder contains water,
It is sparingly soluble in alcohol, acetone, toluene, etc., and mostly soluble in DMSO, DMF, NMP, etc. The infrared (IR) analysis results are as follows.
From the IR spectrum of the KBr powder method, the C=Se stretching vibration, which indicates the presence of a carbon-selenium double bond, was 880 cm ^-1
On the other hand, the vibration of the residual monomer observed at 1260 cm ^-1 was not observed.

The electrical conductivity of this polymer was measured (by press-molding the powder and measuring it as a pellet) and found that it was 10 ^-8 S/cm at room temperature, but when it was brought into contact with iodine vapor under vacuum, it was 10 ^-3 Improved to S/cm.

Example 2 N-methyl-2 used in Example 1 as a solvent
- 10ml dimethyl sulfoxide instead of pyrrolidone
As a catalyst, metal Na is used instead of Na naphthalene.
Fine powder 0.25gr (Na despersion) with benzene 10
Using a catalyst solution dispersed in ml, at room temperature,
Carbon diselenide was polymerized in the same manner as in Example 1 for 15 hours. A reddish-brown to blackish-brown reaction solution was obtained, which was washed and dried in the same manner as in Example 1 to obtain a blackish-brown powder.
Got 4.8gr. As in Example 1, the powder was
It is sparingly soluble in water, alcohol, acetone, toluene, etc., and mostly soluble in DMSO, DMF, and NMP. The results of the IR spectrum obtained by the KBr powder method also showed absorption bands similar to those in Example 1, and it is presumed that a polymer substantially similar to that in Example 1 was produced.

The conductivity of this polymer was also 10 ^-9 S/cm before doping, but it improved to 10 ^-3 S/cm after doping with iodine.

Example 3 Into the reaction vessel used in Example 1, 2 ml (5.3 gr) of carbon diselenide and 20 g of toluene were added while purging with _N2 .
ml and 3 ml of a 15 wt % hexane solution of butyllithium as a catalyst were added, and the mixture was reacted at room temperature with stirring for 15 hours to obtain a reddish brown to blackish brown reaction liquid.
30 ml of a 10 wt % aqueous hydrochloric acid solution was added to the reaction solution, and the catalyst was washed several times with stirring for 1 hour, followed by washing with water until the washing solution became almost neutral. After washing, the toluene solution containing the polymer is distilled under reduced pressure at room temperature to obtain a blackish brown viscous polymer.
Got 0.5gr.

The measurement results of the IR spectrum using the KBr method are shown in Example 1.
Similarly, indicating the presence of a carbon-selenium double bond,
C=Se stretching vibration was observed at 880 cm ^-1 .

Example 4 Carbon diselenide ²
ml (5.3gr) and 30ml of benzene and as catalyst,
After adding 0.2 gr of fine sodium powder and purging with N ₂ , the reactor was sealed and reacted with stirring at a temperature of 100° C. and a pressure of 1.8 Kg/cm ² for 8 hours. A reaction solution containing some blackish brown precipitate was obtained. After the reaction was completed, the temperature was lowered to room temperature, and the catalyst was washed and the polymer was concentrated in the same manner as in Example 3 to obtain 3.2 gr of dark brown powder.

When the infrared absorption spectrum and electrical conductivity of the polymer were measured, almost the same measurement results as those shown in Example 1 were obtained. In this way, a carbon diselenide polymer can be obtained even at high temperatures and under pressure.

Example 5 In the same manner as in Example 1, 1 ml of diselenium carbon
(2.6gr) and 40ml of solvent dimethyl sulfoxide
and 2 ml of 15-crown-5-ether as a catalyst.
Polymerization was carried out at room temperature for 15 hours while dropping a catalyst solution containing 0.3g of sodium methylate into the solution. After the reaction was completed, it was washed and dried in the same manner as in Example 1 to obtain 0.5 gr of reddish brown to blackish brown powder.

The reddish-brown to blackish-brown compound thus obtained exhibits an infrared absorption at 880 cm ^-1 that is thought to be based on the stretching and stretching of C=Se. Furthermore, the electrical conductivity of the polymer was 10 ^-8 S/cm, but it was improved to 10 ^-3 S/cm by doping with iodine.

〔Effect of the invention〕

Conductive polymer materials are lighter and easier to process than conventional metal conductors, so
It has great potential to be used in electromagnetic shielding plates, heating elements, resistance elements, electric wires, electrode plates, etc., and is expected to become a promising industrial material in the future.

The present invention relates to the synthesis of a polymer using carbon diselenide as a starting material as such a conductive polymer material.

This method requires synthesis under harsh conditions at high temperatures (100 to 200 degrees Celsius) and thousands of atmospheres.
It enables synthesis at temperatures below room temperature and even under one atmospheric pressure, making it possible to significantly improve workability. The conductivity of the polymer synthesized according to the present invention is as high as 10 ^-8 S/cm, and the conductivity can be improved to 10 ^-2 to ^{10 -3} S/cm by doping with iodine. have.

Claims (1)

[Scope of Claims] 1. A method for producing a carbon diselenide polymer, which comprises using an anion catalyst as a catalyst in polymerizing carbon diselenide in a solution state. 2. A patent claim characterized in that the anionic catalyst is one or more compounds selected from alkali metals, alkaline earth metals, alkoxide metals, alkyl alkaline earth metals, and derivatives, complexes, and coordination compounds thereof. A method for producing a diselenated carbon polymer according to Scope 1.