DE4100840A1 - New electroconductive pyrrole, thiophene, indolizine and furan copolymers - prepn. by electrolytic polymerisation in bisphenol salt soln. and use - Google Patents

Abstract

New copolymers (I) are derived from pyrrole, thiophene, indolizine and furan cpds. (II) and bisphenol A or phenyl-analogous cpds. (II), (I) being obtd. by reacting (II) in the presence of a conductive salt (IV) and (III) in an electrolyte solvent (V) in known manner. The prepn. of (I) is claimed (see below). Electroconductive homo- and copolymers of 5-membered heterocyclic cpds. (IIA) with a conjugated pi-electron system, contg. N, O or S as hetero-atom, are prepd. by polymerising (IIA) or their mixts. in (V) in the presence of (IV). The polymerisation is carried out in the presence of (III) sulphate. USE/ADVANTAGE - (I) are claimed for use as electrodes for prim. and sec. batteries and as conductors in the electrical industry. They are also useful as sensors and antistatics. (I) have high electrical coductivity and high mechanical properties. Compared with known electroconductive copolymers, they have improved electrochemical discharge capacity and improved long-term stability without embrittlement when stored in air.

Description

The invention relates to a method for producing electrically conductive capable copolymers of compounds from the class of 5-membered heterocyclic compounds with a conjugated π-electron system, which contain nitrogen, oxygen or sulfur as a hetero atom, by Polymerization of these compounds or of mixtures of these compounds in electrolytic solvents in the presence of conductive salts.

In US Patent 35 74 072, the electrochemical polymerization of 5-membered and 6-membered heterocyclic compounds such as Pyrrole, thiophene or furan and their derivatives are described. Information about the copolymerization of these compounds or via electrical properties However, th of the polymers obtained are not in this patent contain.

From DE-OS 34 25 511 a process for the production is electrically conductive capable copolymers of pyrrole with other heterocyclic compounds gene known as thiophene or furan and their derivatives. The polymerization is carried out in the presence of polymerizable conductive salts, so that p-doped polymers are obtained with high electrical conductivity and a high mechanical level compared to known electrically conductive capable pyrrole polymers especially for rechargeable batteries own.

The object of the present invention is to copolymers of Verbin additions from the class of 5-membered heterocyclic compounds create a high electrical conductivity and a possess high mechanical level and compared to known electrical conductive copolymers an improved electrochemical discharge speed and also improved long-term stability without embrittlement Have storage in the air.

It has now been found that the object is achieved by electrically conductive capable copolymers of compounds from the class 5-membered hetero cyclic compounds with a conjugated π electron system, the Contain nitrogen, oxygen or sulfur as a hetero atom, and the one obtained when the polymerization of these compounds or mixtures of these compounds in an electrolyte solvent in the presence of Conductive salts and in the presence of a sulfate of biphenol A or ent  speaking phenyl-analogous compound of bisphenol A. A Another object of the invention is the use of the thus produced Polymers as electrodes for primary and secondary batteries or as Head in electrical engineering as well as sensors and antistatic Materials.

Among compounds from the class of 5-membered heterocyclic Ver bonds with a conjugated π-electron system, the nitrogen, Oxygen or sulfur as a hetero atom are included in this Invention Compounds from the class of pyrroles, thiophenes, Indolicine and the furans understood.

Compounds from the pyrrole class are unsubstituted pyrrole as well as the substituted pyrroles, such as the N-hydroxyalkylpyrroles, N-alkyl pyrroles, N-arylpyrroles, the monoalkyl- or dialkylsub substituted pyrroles and the monohalogen or dihalogen on the carbon atoms substituted pyrroles. In the manufacture of the copoly according to the invention The pyrroles can be used alone or as a mixture with one another be so that the copolymers one or more different pyrroles can contain built-in. The recurring ones are preferred Pyrrole units in the copolymers are essentially unsubstituted Pyrrole itself. Substituted pyrroles are used in the manufacture sets, are the 3,4-dialkylpyrroles, especially those with 1 to 4 carbon atoms in the alkyl radical, such as 3,4-dimethylpyrrole and 3,4-diethylpyrrole, such as the 3,4-dihalopyrroles, in particular 3,4-dichloropyrrole, are also preferred.

Compounds from the class of thiophenes are the unsubstituted thio phen and the 2-, or 3-, methylthiphene, the 2-, 3-, ethylthiophene or other alkyl-substituted thiophenes, as well as the 2-fold substituted with alkyl ized thiophenes, such as 2,3-diethylthiophene or the chlorine substituent thiophenes, such as 2-chloro- or 3-bromothiophene, 3,4-dichlorothiophene. Phenylthiophenes, such as 2-phenylthiophene or 3-benzylthio, also come phen in question.

Compounds from the furan class are the unsubstituted furan as well as the substituted furans, such as alkyl furans, e.g. B. 3-methyl, 2-ethyl or 3-ethyl, also 2,2-dimethyl or 2,3-diethyl furan, and chlorine substituted furans, such as 2-chlorofuran, 3-bromofuran or 3-dichlorofuran, likewise 3,4-difurylfuran or the 2-phenylfuran. Unsubstituted is preferred ized furan.

Compounds from the class of indolicins are the unsubstituted indo licin and the substituted indolicins, such as phenyl and / or alkylindo  licine and bridged derivatives of indolicin (advances in heterocyclic Chemistry, Vol. 23, 104-170, 1976).

Essential to the invention is the measure, the polymerization of the above Compound from the class of 5-membered heterocycles in the presence of Sulfates of bisphenol or compounds with replacement of the phenyl ring by perform analog ring systems. The sulfate of bisphenol is

Corresponding phenyl-analogous compounds are e.g. B.

Me = Na, K, NH₄ or ammonium salt z. B. or 1/2 Mag, Ca, In or 1/2 Fe u. Ä.
or similar compounds in which SR =

means:

All of these compounds can be regarded as reaction products of Aldehydes or ketones with a phenol or a phenol-analogous compound formation (so-called. bisphenol synthesis) with acylation of the carbonyl group and subsequent sulfation.  

The preparation of these compounds is not the subject of the invention.

The manufacturing method according to the invention is in an electrolyte solution made medium that dissolves the monomers and the conductive salts. If with Water-miscible organic solvents can be used to increase electrical conductivity a small amount of water, in all up to 3% by weight, based on the organic solvent be set, even if usually in an anhydrous system and especially also without the addition of alkaline compounds is being processed. The solvent can be aprotic. Preferred electrolyte solvents are e.g. B. acetone, acetonitrile, dimethylformamide, sulfolane, Dimethyl sulfoxide, methylene chloride, N-methylpyrrolidone or propylene carbonate, but it can also be used as an electrolyte in water.

Ionic or ionizable compounds are preferably used as conductive salts. In addition to the alkaline earth metal cations and H⁺, in particular the alkali metal cations, preferably Li⁺, Na⁺ or K⁺, come into consideration as cations for these conductive salts. The onium cations, especially nitrogen and phosphorus, for example of the types R4N⁺ and R4P⁺, in which R is hydrogen and / or lower alkyl radicals, preferably having 1 to 6 carbon atoms, cycloaliphatic radicals, preferably having 6, are very favorable to 14 carbon atoms, or aromatic radicals, preferably having 6 to 14 carbon atoms. Among the ammonium and phosphonium cations, those in which R represents hydrogen and / or an alkyl radical having 1 to 4 carbon atoms are particularly preferred. Examples of preferred onium cations include, in addition to the NH ₄ seien ion, tetramethylammonium, tetraethylammonium, tetra-n-butylammonium, triphenylphosphonium and tri-n-butyl phosphonium cations.

BF ₄ ⁻, AsF ₄ ⁻, AsF ₆ ⁻, SbF ₆ ⁻, SbCl ₆ ⁻, ClO ₄ ^- , HSO ₄ H and SO ₄ ^{2- have} proven to be favorable as anions for the conductive salt. Also suitable are conductive salt anions which are derived from aromatics with acidic groups. Examples are the anions or benzoic acid, phenolsulfonic acid and corresponding nitro compounds, and in particular the anions of aromatic sulfonic acids which may be substituted with alkyl groups. Because of the good results that can be achieved with this, conductive salts with the benzene sulfonic acid anion C ₆ H ₅ SO ₃ ⁻ are particularly preferred. In the simplest case, the salt of the bisphenol A compound itself serves as the conductive salt.

The conducting salt concentration in the process according to the invention is in generally 0.001 to 1, preferably 0.01 to 0.1 mol / liter.

In the preparation of the polymers, preference is given to simple, usual electrolytic cell or electrolysis apparatus consisting of  a cell without a diaphragm, 2 electrodes and an external power source, worked. The electrodes can be made of nickel or titanium, for example or be made of graphite; also precious metal electrodes, preferably platinum electro that can be used. It is beneficial if at least that Anode, but in particular both electrodes, are flat. In a special embodiment of the method according to the invention the anode is also formed from an electrically conductive polymer, such as B. from anodic polypyrrole, poly aniline, doped p-type polyacetylene or doped, p-type Polyphenylene. In this case, the pyrroles and the amino aromatics are on the z. B. polymerized film-shaped conductive polymers.

Depending on the procedure, different types of homo- and Copolymers can be obtained.

Except for the simple electrolytic cell without diaphragm mentioned can also other electrolysis devices for the inventive Ver continue to be used, for example cells with a diaphragm or such with reference electrodes for exact potential determination. To control the The layer thickness of the deposited films is a measurement of the amount of electricity expedient.

The film-like continuous deposition of compounds from the A class of pyrroles on a rotating anode is a preferred one management form.

The deposition or polymerization process is normally carried out at room temperature and under inert gas. Because the reaction temperature structure in the polymerization of the pyrroles has proven to be uncritical however, the temperature can be varied over a wide range as long the solidification temperature or boiling temperature of the electrolyte solution by means of not falling below or exceeding. Generally one has Reaction temperature in the range of -40 to + 40 ° C as very advantageous proven.

Suitable as a power source for the operation of the electrolytic cell any direct current source that has a sufficiently high electrical voltage delivers. The voltage is expediently in the range from about 1 to 25 volts; tensions in the range of about 2 to 12 volts. The current density is usually in Range of 0.05 to 100 mA / cm², preferably in the range of 0.1 to 20 mA / cm².  

The anodically deposited according to the invention during the electrolysis Polymers are used to remove adhering conductive salt with solvents washed and at 30 to 150 ° C, preferably under reduced pressure Pressure, dried. When using graphite, precious metal or similar The electrodes can then be deposited in the form of a film Easily detach copolymers from the electrode, especially if they are thick over 5 µm were deposited. If conductive anode materials are used, film-like polymers or C-fibers are used, as mentioned, the Monomers used according to the invention on the polymeric electrode material polymerized so that in this case a copolymer is obtained in which the polymer used as the anode is also included.

The polymerization of the compounds from the class of 5-membered heterocyclic compounds containing a nitrogen, oxygen or Containing sulfur as a hetero atom can also be in solution with oxygen containing oxidizing agents take place, with water as a solution medium, optionally in a mixture with organic, miscible with water Have proven solvents. It can e.g. B. solvents such as dimethyl sulfoxide, methylene chloride, methanol, ethanol, acetonitrile, sulfolane, Ethylene carbonate, propylene carbonate, dioxane or tetrahydrofuran are used will. When using organic water-immiscible Solvents have incorporated small amounts of water in fine Proven distribution in the organic solvent. Preferably, the Production of the polymers according to the invention, however, uses water. Man expediently works so that the solutions 0.1 to 50, preferably 1 to 5% by weight of the heterocycles mentioned or the mixtures of the heterocycles contain. It is useful to use 1 mole of the heterocyclic verb tion or mixtures of these compounds 0.2 to 10 moles of the oxidation by means of. If you use less than 1 mole, you can see that a Part of the starting substance used is not converted to polymers. It is not necessary to use larger amounts of oxidizing agents, since the amount is sufficient, the total amount of starting materials in polymers convert. However, an excess in excess of the stated amount is in Not necessary in most cases, but may occasionally be certain Effect. Of the oxidants containing oxygen peroxo acids and their salts, peroxodisulfuric acid and their alkali and ammonium salts have proven their worth. Peroxo are also preferred orate or peroxochromates, such as sodium perborate or potassium bichromate turns. Permanganates such as potassium permanganate are also suitable if small amounts of acids are added to these permanganates. It is also preferred the use of hydrogen superoxide, the presence of Conductive salts is unavoidable. The implementation can be conveniently in one Temperature range from 0 to 100 ° C, preferably from 15 to 40 ° C.  

Most often you get satisfactory results when implementing is carried out at room temperature.

In addition to the bisphenol sulfates mentioned or their derivatives additional solutions from the above Conductive salts are added.

The polymers of 5-membered heterocycles obtained by the process according to the invention are highly electrically conductive systems which at least partially contain the sulfates of bisphenol or their derivatives in copolymerized form. The copolymers according to the invention can therefore also be referred to as complexes of cation of the polymers with counter anions. The polymers of the invention have a high mechanical level and an overall balanced, better property profile. They are characterized in particular by the fact that, in contrast to comparable copolymers, they are easier to discharge, ie the discharge process reaches values of 1% by weight without the polymer being damaged. The copolymers according to the invention are therefore particularly suitable as electrodes for primary and secondary batteries or as conductors in electrical engineering; A key feature is the improved long-term stability of these new polymers when stored in the air. The stability was determined in the examples below by comparing the conductivity immediately after production (σ _o ) with the conductivity (σ) after 30 days when stored in a standard climate (20 ° C; 50% relative humidity). The stated amounts in parts relate to the weight.

Examples 1 to 7

Electrochemical polymerization: 15 parts of pyrrole are dissolved in 1600 ml of acetonitrile and 4.8 parts of component I (4,4 '(2-pyridinylmethy len) bisphenol, bishydrogen sulfate) are added. The electrochemical. Polymerization takes place at temperatures around 20 ° C. The current density is 2 mA / cm2. Platinum electrodes 1 mm thick are used as electrodes, which are arranged at a distance of 2 cm. The polymerization time is 90 minutes. During this time, a 40 µm thick film is deposited on the anode. This film is detached from the electrode, washed with water and acetonitrile and dried for 3 hours at 50 ° C. and 10 ^-2 torr.

The electrical conductivity σ (according to the four-point method) is 125 S / cm, and the stability σ / σ _o : 1.0.

Comparative tests Component I

⚫ If the tributylamine salt of benzenesulfonic acid is used as the conductive salt instead of component I (4.5 parts), the conductivity is 135 S / cm and the stability is 0.6.
⚫ If the tetrabutylammonium perchlorate is used as the conductive salt instead of the component (4.5 parts), the conductivity is 132 s / cm and the stability is 0.4.

The following table lists the results when using of components II-VII can be obtained instead of component I.

Claims (4)

1. Copolymer of compounds from the class of pyrrole, thiophene, of indolicin and furan on the one hand and bisphenol A or phenyl analogous compounds of bisphenol A as it is obtained when one a pyrrole, thiophene, indolicin or furan in the presence of a lead salt and a bisphenol A compound in an electrolytic solution implemented in a manner known per se. 2. Process for the production of electrically conductive homo- and copoly merisaten of compounds from the class of the 5-membered heterocyc compounds with a conjugated Π electron system, the Contain nitrogen, oxygen or sulfur as a hetero atom, by Polymerization of these compounds or mixtures of this compound solutions in electrolyte solvents in the presence of conductive salts, characterized in that the polymerization in the presence of Bisphenol A sulfates or phenyl analogue compounds Bisphenol A carries out. 3. Use of polymers, produced by the process according to Claim 2, as electrodes for primary and secondary batteries. 4. Use of polymers produced by the process according to Claim 2, as a leader in electrical engineering.