JPH0668001B2 - Novel copolymer - Google Patents

Description

The present invention relates to a novel polymer, and more particularly to a copolymer suitable for conversion into a novel conductive polymer.

[Conventional technology]

As the polymer used to form the conductive polymer,
Polyacetylene, polyparaphenylene, polythiophene, polypyrrole and the like are known. These polymers can be used as conductive polymers by doping certain compounds, but they have the drawback that they are easily deteriorated in the air and their electrical characteristics change. Further, these conductive polymers have problems such as extremely poor processability due to poor melting and solubility, which is a major obstacle to practical use. For example, as an application field of conductive polymers, application to secondary battery electrodes utilizing the reversible redox properties of conductive polymers has been proposed. Is physically or chemically unstable,
Therefore, the stable repeatability of charge and discharge (cyclability), which is the basic performance required for secondary batteries, cannot be expected. Further, since the polymer skeleton of the conductive polymer is made of a rigid π-electron conjugated system, it is insoluble and infusible, which is a major obstacle to practical use. As a method of solving these problems, US Pat. No. 4,505,844 proposes an electroactive polymer obtained by doping a polymer having a 3,10-phenoxazinediyl structure as a repeating unit with an electron acceptor. .

[Problems to be solved by the invention]

However, the above-mentioned phenoxazine-based polymer is an oligomer having a low degree of polymerization, and does not have mechanical strength and moldability that should be originally provided as a polymer compound. For example, when the polymer is used as an electrode material for a secondary battery. However, there is a problem that the soluble component elutes with repeated charge and discharge, so that cyclovirity cannot be expected. Further, in order to provide the above-mentioned phenoxazine-based polymer with good electrochemical properties as well as mechanical strength and moldability, it is necessary to obtain a polymer having a higher degree of polymerization (high polymer). It is difficult to obtain a high molecular weight polymer even by Grignard coupling, oxidative coupling, Friedel-Crafts reaction and electrolytic oxidative polymerization, which are generally used as a synthetic method for a synthetic compound or polyheteroaromatatic. However, even if the reaction conditions are made more severe, not only can a high molecular weight not be expected by inducing a heterologous bond or a cross-linking reaction, but one of the advantages of a high molecular compound is lost the processability and insolubility and infusibility. There is a problem that it becomes an inactive polymer.

[Means for solving problems]

An object of the present invention is to solve the problems of the prior art.

That is, the invention relates to the general formula I (In the formula, R is H, a hydrocarbon residue having 1 to 20 carbon atoms, a furyl group, a pyridyl group or a methoxyphenyl group, and n is 1 to
50, preferably an integer of 2 to 30, x is 2 to 1000,
Preferably, it represents an integer of 2 to 500. ), The electroactive polymer having excellent properties can be obtained by doping the copolymer with an electron acceptor.

The copolymer represented by the general formula (I) of the present invention has the general formula (I
It can be obtained by polycondensing a compound having a 3,10-phenoxazinediyl structure represented by I) as a repeating unit with an aldehyde represented by the general formula (III) or a polymer thereof.

As the compound represented by the general formula (II), a polymer having a phenoxazine or 3,10-phenoxazinediyl structure as a repeating unit is used.

The polymer having a 3,10-phenoxazinediyl structure represented by the general formula (II) as a repeating unit is, for example, permanganate or dichromate in acetone, pyridine, benzene, water or a mixed solvent thereof. Can be synthesized using an oxidizing agent such as. Further, a phase transfer catalyst such as tetraalkylammonium hydrogensulfate or crown ether may be used together with these oxidizing agents.

Examples of the aldehyde represented by the general formula (III) include R in the formula
Is hydrogen or a hydrocarbon residue having 1 to 20 carbon atoms, preferably 1 to 8, or a compound having a furyl group, a pyridyl group or a methoxyphenyl group, and as the hydrocarbon residue, a methyl group, an ethyl group, n-propyl group, i-propyl group, n-butyl group, i-butyl group, n-hexyne group or allyl group, various aryl groups such as phenyl group, tolyl group, ethylphenyl group, aralkyl group and derivatives thereof Can be used. Typical examples of these aldehydes include formaldehyde, acetaldehyde, propionaldehyde, butyraldehyde, benzaldehyde, acrylaldehyde, cinnamaldehyde, anisaldehyde, nicotinaldehyde and furfural.

The aldehyde polymer is a polymer obtained by self-condensing an aldehyde represented by the general formula (III) as a concentrated solution or condensing in the presence of an acid catalyst. It represents a compound that is easily hydrolyzed to form an aldehyde monomer under the reaction conditions for synthesizing the copolymer of the invention. Typical examples include paraformaldehyde, which is a polymer of formaldehyde, and paraaldehyde, which is a trimer of acetaldehyde.

The polycondensation of the compound represented by the general formula (II) and the aldehyde represented by the general formula (III) or a polymer thereof is carried out in an organic solvent in which both are soluble at a temperature of 0 to 200 ° C. with an acid or alkali catalyst. Can be done using. Examples of acid catalysts include inorganic acids such as sulfuric acid, hydrochloric acid and phosphoric acid, and organic acids such as formic acid, acetic acid and propionic acid. Examples of preferable organic solvents include ethyl ether, tetrahydrofuran, ethers such as dioxane, chloroform,
Halogenated hydrocarbons such as dichloromethane and chlorobenzene, nitro compounds such as nitrobenzene, acetonitrile, propylene carbonate, dimethylformamide,
Examples thereof include N-methylpyrrolidone. Reaction time is 1
It can be appropriately selected within the range of minutes to 100 hours, preferably 5 minutes to 24 hours.

By the above reaction, the copolymer of the present invention which is substantially linear and has a high degree of polymerization is obtained. The copolymer of the present invention is soluble in solvents such as N-methylpyrrolidone, nitrobenzene and sulfuric acid, but is insoluble in alcohol, hydrocarbons, acetonitrile and propylene carbonate used in organic electrolyte type batteries, and when heated, It is a thermoplastic resin that can be melted, has excellent processability, and can be formed into various shaped articles of any shape.

The copolymer of the present invention shows high electric activity by doping with an electron acceptor as a dopant and can carry out a redox reaction with good repeatability. Therefore, when used as an electrode material of a secondary battery, for example, it is reversible. Charge and discharge are possible, and even if the number of charge and discharge repetitions (cycle number) is remarkably increased, the elution phenomenon does not occur and the cyclability does not decrease as seen in the case of the phenoxazine-based polymer. It is possible to obtain extremely stable characteristics.

Electron-accepting dopants include halogen compounds such as iodine, bromine, hydrogen iodide, arsenic pentafluoride, phosphorus pentachloride, phosphorus pentafluoride, antimony pentafluoride, silicon tetrafluoride, aluminum chloride, aluminum bromide. , Aluminum fluoride, metal halides such as ferric chloride, sulfuric acid, nitric acid, protic acids such as chlorosulfonic acid, sulfur trioxide, oxidizing agents such as difluorosulfonyl peroxide, tetracyanoquinodimethane, etc. There can be mentioned various organic substances. In addition, as a dopant that can be electrochemically doped, V such as PF ₆ ⁻ , SbF ₆ ⁻ , AsF ₆ ⁻ is used.
halide anions of a metal selected, BF ₄ ^-, such as III
halide anions of a metal ^{_{selected, I - (I 8 -)}} , Br -, C
1 ^- halogen anion such as, C1O ₄ ^- anions such as perchlorate anions such as.

Further, the copolymer of the present invention has a property that the nitrogen atom in the polymer is positively charged and is in a stable state when doped with an anion, so that the copolymer is stable against repeated redox and has a processability. It is used to form various functional electrodes such as batteries by utilizing the characteristic of goodness. That is, the copolymer of the present invention is molded by using the one dissolved in a solvent, heat-melted and molded, or pressure-molded with the copolymer as a main component, or by using a binder. An electrode can be formed in any shape. Examples of the binder include, but are not limited to, polytetrafluoroethylene, polyvinylidene fluoride, polyvinyl chloride, and polyethylene.

〔The invention's effect〕

Since the copolymer of the present invention is linear, it has excellent processability, and various molded products can be easily manufactured. Also,
By doping this copolymer with an electron acceptor, it is possible to express high conductivity, and even if the doping is reversible and it has extremely high cyclability, it can be used as a conductive polymer. Are better.

〔Example〕

Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited thereto.

Example 1. (Synthesis of phenoxazine oligomer) 3 equipped with stirrer, dropping funnel and reflux condenser
Acetone (150 m) and phenoxazine (5.1 g) were placed in a 00 m three-necked flask and stirred to dissolve phenoxazine, followed by cooling with ice. Then, a saturated acetone solution of potassium permanganate was added dropwise. After adding 10.5 g of potassium permanganate, the reaction was terminated, and the precipitate was filtered and washed with acetone. After air-drying, the mixture was placed in hot toluene and stirred, and insoluble manganese dioxide was separated by filtration. The crude crude phenoxazine oligomer powder was obtained by removing toluene from the filtrate under reduced pressure. The crude phenoxazine oligomer powder was redissolved in toluene again and purified by reprecipitation with methanol to obtain 3.3 g of purified phenoxazine oligomer. The yield was 65%.

(Polycondensation of phenoxazine oligomer and formaldehyde) The above phenoxazine oligomer was added to a 50 m three-necked flask.
0.30g was put and it was made to melt | dissolve in 1,4-dioxane 5m. A few drops of concentrated sulfuric acid were added thereto, 40 mg of a 37% aqueous formaldehyde solution was added dropwise, and then the mixture was reacted by heating and stirring at 80 ° C. for 1 hour. After the reaction, the reaction precipitate was filtered, washed with methanol and dried to obtain 0.31 g of a green polymer.
The obtained polymer was soluble in N-methylpyrrolidone and nitrobenzene, but insoluble in acetonitrile, propylene carbonate and hydrocarbons.

The result of measuring the infrared absorption spectrum is shown in FIG. 8
Absorptions derived from 1,2,4-trisubstituted benzenes at 00 cm ^-1 and 870 cm ^-1 , absorptions derived from 1,2-disubstituted benzenes at 750 cm ^-1 were observed, and other absorption positions were phenoxazine. From the agreement with the infrared absorption spectrum of the oligomer, it was found that polycondensation with the aldehyde occurred at the 3-position at the end of the phenoxazine oligomer.

Reference example 1. The copolymer obtained in Example 1 was pressure-bonded onto a platinum mesh to prepare a measuring electrode. Of 0.07mo1 / 1 as an electrolytic solution n-C ₄ H ₉ NC1
Cyclic voltammetry of the above electrodes was measured in a dry nitrogen atmosphere using an O ₄ acetonitrile solution, a platinum plate as a counter electrode, and an Ag / AgNO ₃ electrode as a reference electrode. The sweep speed was 50 mV / sec. The obtained results are shown in FIG. It showed reversible and extremely stable redox behavior with no change even after several tens of redox cycles. Redox potential is 0.46VVS. It was Ag / AgNO ₃ .

Example 2. A reaction was carried out in the same manner as in Example 1 except that the above phenoxazine was used instead of the phenoxazine oligomer in Example 1. 0.70 g of phenoxazine,
A 37% aqueous formaldehyde solution, 0.70 g, and 15 m of 1,4-dioxane were used and reacted in a greenhouse for 30 minutes.
After purification, 0.75 g of a polycondensation reaction product was obtained.

Reference example 2. Cyclic voltammetry was measured in the same manner as in Reference Example 1, except that the copolymer obtained in Example 2 was used in place of the polycondensation reaction product of the phenoxazine oligomer and formaldehyde in Reference Example 1. I went. The obtained results show reversible and extremely stable redox behavior as shown in FIG. Redox potential is 0.36V VS Ag / Ag
It was NO ₃ .

[Brief description of drawings]

FIG. 1 is an infrared absorption spectrum of the copolymer obtained in Example 1, and FIGS. 2 and 3 show the results of cyclic voltammetry of the electrodes in Reference Examples 1 and 2, respectively.

Claims (1)

[Claims] 1. A general formula (In the formula, R represents H, a hydrocarbon residue having 1 to 20 carbon atoms, a furyl group, a pyridyl group or a methoxyphenyl group, and n
Is an integer of 1 to 50, and x is an integer of 2 to 1000. ) A copolymer represented by.