EP2066723A1

EP2066723A1 - Process for preparing polythiophenes

Info

Publication number: EP2066723A1
Application number: EP07820352A
Authority: EP
Inventors: Knud Reuter; Stephan Kirchmeyer; Udo Merker; Peter Wilfried Loevenich; Timo Meyer-Friedrichsen
Original assignee: HC Starck GmbH
Current assignee: Heraeus Deutschland GmbH and Co KG
Priority date: 2006-09-20
Filing date: 2007-09-19
Publication date: 2009-06-10
Also published as: DE102006044067A1; US20090310285A1; WO2008034848A1

Abstract

The invention relates to a novel process for preparing polythiophenes, especially conductive polythiophenes, and to the use of specific organic peroxides as oxidizing agents in the oxidative polymerization of thiophenes.

Description

Process for the preparation of folthiophenes

The invention relates to a novel process for the preparation of polythiophenes, in particular conductive polythiophenes and the use of special peroxidic compounds as Oxidati- onsmittel in the oxidative polymerization of thiophenes.

The class of compounds of π-conjugated polymers has been the subject of numerous publications in recent decades. They are also referred to as conductive polymers or as synthetic metals.

Conductive polymers are increasingly gaining in economic importance because polymers have advantages over metals in terms of processability, weight, and targeted chemical properties modification. Examples of known π-conjugated polymers are polypyrroles, polythiophenes, polyanilines, polyacetylenes, polyphenylenes and poly (p-phenylenes-vinylenes). Layers of conductive polymers are used in a variety of technical applications.

The production of conductive polymers is carried out chemically or electrochemically oxidatively from precursors for the preparation of conductive polymers such. B. optionally substituted thiophenes, pyrroles and anilines and their respective optionally oligomeric derivatives. In particular, the chemically oxidative polymerization is widespread because it is technically easy to implement in a liquid medium or on a variety of substrates.

A particularly important and industrially utilized polythiophene is poly _(ethylene-3? 4-dioxythio- phen) having in its oxidized form of very high conductivity and is described for example in EP 339 340 A2. An overview of numerous poly (alkylene-3,4-dioxythioρhene) -

Derivatives, in particular poly (ethylene-3,4-dioxythiophene) derivatives, their monomeric building blocks, syntheses and applications are given by L. Groenendaal, F. Jonas, D. Freitag, H. Pielartzik & J.R. Reynolds, Adv. Mater. 12, (2000) p. 481-494.

Technically customary or mentioned in the literature and patent literature oxidizing agent for the preparation of poly (ethylene-3,4-dioxythiophene), (PEDT or PEDOT, hereinafter referred to as PEDT) of ethylene-3,4-dioxythiophene (EDT or EDOT, hereinafter Called EDT) come z. From the classes of inorganic peroxide compounds or transition metal salts.

Suitable inorganic oxidizing agents of the prior art are, for example, hydrogen peroxide, sodium perborate, persulfates (peroxodisulfates) of the alkali metals, such as sodium or potassium persulfate, or ammonium persulfate. In a chemically related manner, the oxidation takes place with air or oxygen.

Such oxidizing agents are particularly suitable for the preparation of polythiophene dispersions, especially poly (ethylene-3,4-dioxythiophene) dispersions, as described in EP-A 440 957. - - the. Such aqueous dispersions preferably contain polymeric sulfonic acids as polyanions, which take on the role of the counterions for the poly (ethylen-3,4-dioxythiophene) cations.

A disadvantage of the inorganic peroxidic oxidizing agents with the exception of hydrogen peroxide is the restriction to aqueous systems. Thus, they are not suitable for the preparation of conductive polymers by polymerization of organic solution. In addition, many of these oxidizing agents have a tendency to oxidize the sulfur atoms of the thiophene ring, which under certain circumstances can lead to a limitation of the achievable electrical conductivity or to the formation of by-products. With H ₂ θ ₂ , neither an aqueous, highly conductive PEDT: PSS dispersible nor a highly conductive s / to-polymerized layer of alcoholic H ₂ O ₂ solution can be obtained for these reasons.

As the oxidizing agent suitable transition metal salts of the prior art are, for. B. ferric salts such as FeCl ₃ , ferric perchlorate, ferric sulfate, ferric tosylate or other Fe-IH sulfonates, such as. Ferric camphorsulfonate, cerium tV salts, potassium permanganate, potassium dichromate, or cupric salts such as copper O-tetrafluoroborate.

A disadvantage of oxidizing agents based on such transition metal salts is the formation of salts of these metals in lower oxidation states (eg Fe-II salts, Mn-IV compounds, Cu-I salts) as inevitably produced by-products. In a technical use of conductive layers, which are based on z. B. of EDT and Fe-Ilϊ salts z. B. for use in capacitors, these salts or remaining in the conductive layer transition metal ions can interfere with lower oxidation levels and must be washed out as completely as possible in the rule. This often requires several washes. Otherwise, the crystallization of the salts over time can lead to increased series resistance due to contact resistance occurring. In addition, the crystals can damage the dielectric or the outer contact layers under mechanical stress of the capacitor, so that the residual current increases.

US-A 20060062958 describes the use of benzoyl peroxide as organic peroxide as an oxidizing agent for the polymerization of monomers. However, the use of diacylpexides such as benzoyl peroxide leads, with different experimental conditions, to polymers with low conductivity or to incomplete polymerization with poor film formation.

In general, US-A 20060065889 describes the oxidative polymerization of monomers with the aid of organic peroxides to obtain a solution of a conductive polymer. In the case of EDT as a monomer, the procedure described leads to a polymer solution with greatly altered optical properties and a lower conductivity compared to conventionally produced polymer. The procedure and the product properties indicate that the process described leads to over-oxidation of the polymer, resulting in a reduction in conductivity.

There is therefore a need for oxidizing agents for the production of polythiophenes by means of chemical oxidative polymerization, which do not have the disadvantages mentioned.

The object of the present invention was to find suitable oxidizing agents for the oxidative polymerization of thiophenes, for example for the preparation of polythiophene dispersions or for the in-situ deposition of polythiophenes, and in particular a process for the preparation of polythiophenes by means of chemically oxidative in situ To provide polymerization, wherein no subsequent complete removal of transition metal clays is required.

This object has surprisingly been found by the use of special organic peroxidic compounds as oxidizing agents for the production of polythiophenes by means of oxidative polymerization. When using the specific organic peroxide compounds, only very small amounts of additional transition metal ion-containing catalysts are required, e.g. Fe, Co, Ni, Ce, V, Zr ions in the form of soluble salts (eg tosylates), preferably Fe-II, Fe-III, Co-II and Co salts. III ions. Another way to catalytically accelerate the

Peroxide reaction consists in the addition of small amounts of tert. Amines, e.g. B. the known from the UP resin technology compounds such as N, N-dimethylaniline, N, N-diethylaniline, the corresponding toluidines or chloroanilines and optionally also N, N-bis (hydroxyethyl) anilines and their polymeric derivatives. A complete and time-consuming removal of transition metal ions is thus eliminated.

The present invention thus provides a process for the preparation of polythiophenes by oxidative polymerization of thiophenes or thiophene derivatives for the preparation of polythiophene dispersions or for in-situ deposition of polythiophenes, characterized in that at least one organic peroxidic compound is used as the oxidizing agent, wherein this organic peroxide compound is not a diacyl peroxide.

Preference is given according to the inventive method polythiophenes containing recurring units of the general formula (I),

(D wherein

R ¹ and R ² are each independently H, an optionally substituted C ₁ -C ₁₈ alkyl radical or an optionally substituted Q-Qg alkoxy radical, or

R ¹ and R ² together represent an optionally substituted C 1 -C 6 -alkylene radical, an optionally substituted C 1 -C ₈ -alkylene radical in which one or more carbon atoms may be replaced by O, preferably a CpCg-dioxyalkylene radical or a optionally substituted propene-1,3-diyl radical, in which optionally the C-3 atom may be replaced by a heteroatom selected from O or S,

by oxidative polymerization of thiophenes of the general formula (II),

wherein R ¹ and R ^{2 have} the meaning given for the general formula (I),

produced.

Particular preference according to the inventive method polythiophenes containing recurring units of the general formula (I-a) and / or (I-b)

wherein

is an optionally substituted Q-Cs-alkylene radical, preferably an optionally substituted C ₂ -C ₃ -alkylene radical,

Y is O or S, preferably S, R is a linear or branched, optionally substituted Ci-C _ä g alkyl group, an optionally substituted C ₅ -CJ ₂ cycloalkyl radical, an optionally substituted C _e -C ₄ aryl, an optionally substituted C ₇ -CJ "aralkyl radical, is an optionally substituted Ci-CrHydroxyalkylrest or a hydroxyl radical,

x is an integer from 0 to 8, preferably 0 or 1, and

in the case where several radicals R are attached to A, they may be the same or different,

by oxidative polymerization of thiophenes of the general formula (II-a) and / or (o-b),

(II-a) (ü-b)

wherein A, Y, R and x are as defined for general formulas (II-a) and (II-b),

produced.

The general formula (I-a) is understood to mean that x substituents R can be bonded to the alkylene radical A.

Polythiophenes containing recurring units of the general formula (I-a) are preferably those containing recurring units of the general formula (I-a-1),

wherein

R and x have the abovementioned meaning. Particular preference is given to those polythiophenes containing recurring units of the general formula (I-aa-1)

In particularly preferred embodiments, the polylhiophene having repeating units of the general formula (Ia) and / or (Ib) is poly (3,4-ethylenedioxythiophene) or poly (thieno [3 _> 4-b] thiophene, ie a homopolythiophene of repeating units of Formula (I-aa-1) or (I-b).

In further particularly preferred embodiments, the polythiophene having repeating units of the general formula (I-a) and / or (I-b) is a copolymer of recurring units of the formula (I-aa-1) and (I-b).

The polythiophenes may be neutral or cationic. In preferred embodiments, they are cationic, with "cationic" referring only to those located on the polythiophene backbone Depending on the substituent on the R radicals, the polythiophenes can carry positive and negative charges in the structural unit, with the positive charges on the polythiophene main chain and the negative charges may be present on the radicals R substituted by sulfonate or carboxylate groups, in which case the positive charges of the polythiophene main chain may be partially or completely saturated by the optional anionic groups on the radicals R. On the whole, the polythiophenes in these cases can be cationic, neutral or even anionic, yet they are all considered as cationic polythiophenes in the context of the invention, since the positive charges on the polythiophene main chain are definitive The positive charges are not in the formulas shown, because their exact number and position can not be determined correctly. However, the number of positive charges is at least 1 and at most n, where n is the total number of recurring units (equal or different) within the polythiophene.

^"2 ^{Sem" 1} are preferred with the inventive method conductive polythiophenes with a specific conductivity of more than 10 ^"3 ^{Sem" 1,} more preferably from 10 produced. , ,

To compensate for the positive charge, as far as this is not already done by the optionally Su nn- or carboxylate-substituted and thus negatively charged radicals R, the cationic polythiophenes require anions as counterions,

The process according to the invention is preferably carried out in the presence of at least one counterion.

Suitable counterions are monomeric or polymeric anions, the latter also being referred to below as polyions.

Preferred polymeric anions are, for example, anions of polymeric carboxylic acids, such as polyacrylic acids, polymethacrylic acids or polymaleic acids, or polymeric sulfonic acids, such as polystyrenesulfonic acids and polyvinylsulfonic acids. These polycarboxylic and sulfonic acids can also

Copolymers of vinyl carboxylic and vinyl sulfonic acids with other polymerizable monomers, such as acrylic acid esters and styrene. These may, for example, also be partially fluorinated or perfluorinated polymers containing S (VM ⁺ or COOTVl ⁺ groups, where M ^{+ is} , for example, ⁺ , Li ⁺ , Na ⁺ , K ⁺ , Rb ⁺ , Cs ⁺ or NH4 ⁺ , preferably H ⁺ , Na ⁺ or K ⁺ is in such 80 ₃ ^"M ⁺ - or ^COO". M ⁺ groups partially fluorinated containing or perfluorinated polymer can be, Nafion ^®, which is for example commercially available in the trade, for example, mixtures of one. or more of these polymeric anions are suitable.

Particularly preferred as a polymeric anion is the anion of polystyrene sulfonic acid (PSS) as a counterion.

The molecular weight of the polyanionic polyacids is preferably 1,000 to

2000 00o ₅ more preferably from 2000 to 500 000. The polyacids or their alkali salts are commercially available which can be prepared (for example polystyrene sulfonic acids and polyacrylic acids, or by known processes, see for example Houben-Weyl, Methods of Organic Chemistry, Vol. E 20 Macromolecular Materials , Part 2, (1987), p. 1141).

The monomeric anions such as those from Ci-C ₂ o-serve Alkansu] fonsäuren ₅ such as methane, ethane, propane, butane or higher sulphonic acids, such as dodecane, of a- liphatischen perfluorosulfonic acids, such as trifluoromethanesulfonic acid, Perfluorbutansulfcnsäu - Re or perfluorooctane sulfonic acid, aliphatic Ci-Qo carboxylic acids such as 2-ethylhexylcarboxylic acid, aliphatic perfluorocarboxylic acids such as trifluoroacetic acid or perfluorooctanoic acid, and aromatic, optionally substituted by Ci-C ₂ o-alkyl sulfonic acids such as benzenesulfonic acid, o Toluenesulfonic acid, p-toluenesulfonic acid, dodecylbenzenesulfonic acid, dinonylnaphthalenesulfonic acid or dinonylnaphthalenedisulfonic acid, and of cycloalkanesulfonic acids such as camphorsulfonic acid or tetrafluoroborates, hexafluorophosphates, perchlorates, hexafluoroantuanates, hexafluoroarsenates or hexachloroantimonates. Particular preference is given to the anions of p-toluenesulfonic acid, methanesulfonic acid or camphorsulfonic acid.

It is also possible to use anions of the oxidizing agent used or of anions formed after the reduction as counterions, so that addition of additional counterions is not absolutely necessary.

Canonical polythiophenes which contain anions as counterions for charge compensation are also often referred to in the art as polythiophene / (poly) anion complexes.

Preferred thiophenes of the general formula (II-a) are those of the general formula (II-a-1)

Particularly preferred as thiophenes of the general formula (II-a) are those of the general

Formula (II-aa-1)

used.

For the purposes of the invention, derivatives of the thiophenes listed above are understood as meaning, for example, dimers or trimers of these thiophenes. There are also higher molecular weight derivatives, ie tetramers, pentamers, etc. of the monomeric precursors as derivatives possible. The derivatives can be constructed from the same or different monomer units and can be used in pure form and mixed with one another and / or with the abovementioned thiophenes. Oxidized or reduced forms of these thiophenes and thiophene derivatives are also included within the meaning of the invention by the term thiophenes and thiophene derivatives, provided that the same conductive polymers are formed during their polymerization as in the thiophenes and thiophene derivatives listed above. Processes for the preparation of the thiophenes and their derivatives are known to the person skilled in the art and are described, for example, in L. Groenendaal, F. Jonas, D. Freitag, H. Pielartzik & JR Reynolds, Adv. Mater. 12 (2000) 481-494 and references cited therein.

The thiophenes may optionally be used in the form of solutions. Suitable solvents which may be mentioned are, in particular, the following organic solvents which are inert under the reaction conditions: aliphatic alcohols, such as methanol, ethanol, .alpha.-propanol and butanol; aliphatic ketones such as acetone and methyl ethyl ketone; aliphatic carboxylic acid esters such as ethyl acetate and butyl acetate; aromatic hydrocarbons such as toluene and xylene; aliphatic hydrocarbons such as hexane, heptane and cyclohexane; Chlorinated hydrocarbons such as dichloromethane and dichloroethane; aliphatic nitriles such as acetonitrile, aliphatic sulfoxides and

Sulfones such as dimethylsulfoxide and sulfolane; aliphatic carboxylic acid amides such as methylacetamide, dimethylacetamide and dimethylformamide; aliphatic and araliphatic ethers such as diethyl ether and anisole. Furthermore, water or a mixture of water with the aforementioned organic solvents may also be used as the solvent. Preferred solvents are alcohols and water and mixtures containing alcohols or water or mixtures of

Alcohols and water.

Thiophenes, which are liquid under the oxidation conditions, can also be polymerized in the absence of solvents.

In the context of the invention, C 1 -C ₅ -alkylene radicals A are methylene, ethylene, n-propylene, n-butylene or n-pentylene, C 1 -C ₈ -alkylene radicals furthermore n-hexylene, n-heptylene and n-octylene. Ci-Cg

Alkylidene radicals are C 1 -C ₈ -alkylene radicals listed above in the context of the invention containing at least one double bond. C _t -Cg-Dioxyalkylenreste, C _r Cg-Oxythiaalkylenreste and C _r Cg-Dithiaalkylenreste stand in the context of the invention for the CJ -C ₈ -Dioxyalkylenreste corresponding to the above-mentioned Cj-Q-alkylene radicals, Ci-Cg-Oxythtaalkylenreste and Ci C ₈ - Dithiaalkylene radicals. Ci-C _{! S-} alkyl is in the context of the invention for linear or branched C, -

Cis-alkyl radicals such as methyl, ethyl, n- or Ϊso-propyl, n-, iso-, sec- or tert-butyl, n ~ pentyl, 1-methylbutyl, 2-methylbutyl, 3-methylbutyl, 1-ethylpropyl, 1 , 1-dimethylpropyl, 1,2-dimethylpropyl, 2,2-dimethylpropyl, n-hexyl, n-heptyl, n-octyl, 2-ethylhexyl, n-nonyl, n-decyl, n-undecyl, n-dodecyl, n -Tridecyl, n-tetradecyl, n-hexadecyl or n-octadecyl, _{_C5-Ci2} cycloalkyl of C ₅ -C ₂ -cycloalkyl, such as cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, cyclononyl or cyclodecyl, C ₅ -C ₄ - Aryl for Q-Cμ-aryl radicals such as phenyl or naphthyl, and C ₇ -C ₈ -aralkyl for C 1 -C ₅ -glyalkyl radicals such as, for example, benzyl, o-, m-, p-tolyl, 2,3-, 2,4-, 2,5-, 2,6-, 3,4-, 3,5-xylyl or mesityl. C 1 -C ₃₈ -alkoxy radicals are in the context of the invention for the alkoxy radicals corresponding to the Ci-Cjg-alkyl radicals listed above. The preceding list serves to exemplify the invention and is not to be considered as exhaustive. - -

If further substituents of the preceding radicals are suitable, numerous organic groups are suitable, for example alkyl, cycloalkyl, aryl, halogen, ether, thioether, sulfa, sulfoxide, sulfone, sulfonate, amino, Aldehyde, keto, carboxylic ester, carboxylic acid, carbonate, carboxylate, cyano, alkylsilane and alkoxysilane groups, and carboxylamide groups.

For the purposes of the present invention, organic peroxides are to be understood as meaning organic peroxides, hydroperoxides, peresters or percarboxylic acids with one or, if appropriate, also several peroxidic groups. Furthermore, organic peroxidic compounds within the meaning of the invention also mean derivatives or salts of peroxodisulfuric acid HjS ₂ Og or Caro's acid HjSO ₅ , provided that they contain at least one organic radical in the form of an alkyl or aryl group or an organically substituted ammonium or phosphonium ions.

Preferred organic peroxides are dialkyl peroxides such as di-tert-butyl peroxide, di-tert-amyl peroxide, and aromatic-substituted dialkyl peroxides such as dicumyl peroxide or tert-butyl-cumyl peroxide (III). Preferred organic peroxides are also those which contain a plurality of peroxy groups, such as bis (tert-butylperoxyisopropyl) benzene (IV), 2,5-bis (tert-butylperoxy) -2,5-dimethylhexane (V), 2, 5-di (tert-butylperoxy) -2,5-dimethyl-3-hexyne (VI), 1,1-di- (tert-butylperoxy) -3,3,5-trimethylcyclohexane (VII), 2,2 -Di (tert-butylperoxy) butane (VIII).

The compounds of the formulas (III) to (Vϊlϊ) are shown below by way of example:

(IV) _ -

Further, 3,3,5,7,7-pentamethyl-1,2,4-trioxepane (IX) is one of the preferred peroxides as an example of a heterocyclic peroxide containing heteroatoms such as O in this case.

Preferred organic hydroperoxides are also alkyl hydroperoxides such as tert-butyl hydroperoxide, tert-amyl hydroperoxide, or aromatic substituted alkyl hydroperoxides such as cumyl hydroperoxide. - -

The group of preferred peroxides also includes those compounds which have been classified as "ketone peroxides" in the scientific literature and in the chemicals trade, such as methyl ethyl ketone peroxide, methyl isopropyl ketone peroxide, methyl isobutyl ketone peroxide, cyclohexanone peroxide and acetylacetone peroxide different structures are discussed or indicated in the literature, where mixtures may be present and often also peroxide and hydroperoxide structures in the same molecule may occur. [0113] In the following, some structures are exemplified, (X) to (XVI):

(XIII) - -

Preferred organic peroxide compounds are also peresters, ie, for example, esters of aliphatic or aromatic percarboxylic acids or organic percarbonates (esters of percarbonic acid). Examples which may be mentioned are tert-butyl-peroxy-2-ethylhexanoate (XVII), tert-butyl-pereoxy-3,5,5-trimethylhexanoate (XVIII), 2,5-dimethyl-2,5-di (2-ethylhexanoylperoxy) hexane (XIX), tert-butyl peroxybenzoate, tert-butyl monoperoxymaleate (XX), butyl-4,4'-di (tert-butyloxy) valerate (XXI), di (tert-butylcyclohexyl) peroxydicarbonate (XXII ) ₅ tert-butyl-peroxy isopropyl carbonate (XXIII).

(XVIIΪ) - -

(XXI)

(XXIII)

Furthermore, dimethyldioxirane (XXIV) is one of the preferred peroxides. ⁰ ° (XXIV)

Furthermore, preferred organic peroxide compounds are peracids (percarboxylic acids), such as. Peracetic acid, perpropionic acid, perbenzoic acid, m-chloroperbenzoic acid ^1, etc.

Another group of organic compounds with peroxide function which is suitable and preferred according to the invention are organic salts of peroxodisulphuric acid (H ₂ SjO 3) or of the persulphuric acid (also called Caro's acid, H ₂ SO 3). Organic salts are all those salts whose cations from the group of ammonium and phosphonium ions have at least one, preferably 2 to 4, more preferably 4 organic radicals A, which may be the same or different in the presence of several radicals A. , Examples of A may be mentioned C _r to C _{! 8} alkyl, z. Methyl, ethyl, n-propyl, iso-propyl, n-, iso-, sec- or tert-butyl, n-pentyl, 1-

Methylbutyl, 2-methylbutyl, 3-methylbutyl, 1-ethylpropyl, 1,1-dimethylpropyl, 1,2-dimethylpropyl, 2,2-dimethylpropyl, n-hexyl, n-heptyl, n-octyl, 2-ethylhexyl, n-nonyl, n-decyl, n-undecyl, n-dodecyl, n-tridecyl, π-tetradecyl, n-hexadecyl or n-octadecyl, further C ₅ -Cn-CycJoalkylreste such as cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, cyclononyl or cyclodecyl, furthermore Cs-Cw-aryl radicals such as phenyl or naphthyl, and C ₇ -C ₅₈ -aralkyl radicals such as, for example, benzyl, o-, m-, p-tolyl, 2,3-, 2,4-, 2, 5-, 2,6-, 3,4-, 3,5-xylyl or mesityl. Organic ammonium salts of peroxodisulphuric acid (A ^ N ⁺⁾ ₂ S ₂ Og, ^"z. B. Especially preferred are tetra-n-butylammonium peroxodisulfate.

The oxidative polymerization of the thiophenes of the formula (II), depending on the oxidant used and the desired polymerization time generally at temperatures of -10 to +

250 ⁰ C, preferably at temperatures of 0 to 200 ⁰ C, more preferably made at temperatures from 0 to 100 ⁰ C. Depending on the batch size, polymerization temperature and oxidizing agent, the polymerization time can be from a few minutes to several days. In general, the polymerization time is between 30 minutes and 150 hours.

The oxidative polymerization of the thiophenes of the formula (II) theoretically requires per mole of thiophene

2.25 equivalents of oxidizing agent (see, for example, J. Polym Sc, Part A, Polymer Chemistry VoI, 26, page 1287 (1988).) However, it is also possible to use oxidizing agents in a smaller amount than is theoretically required For example, thiophenes and oxidants are used in a weight ratio of 4: 1 to 1:20, but in preferred embodiments, the oxidant is used in some excess, eg, an excess of 0.1 to 2 equivalents per mole of thiophene 2.25 equivalents of oxidizing agent are used per mole of thiophene, and a peroxide group -OO- corresponds to two oxidation equivalents. - -

It is extremely surprising that the organic peroxidic compounds to be used according to the invention lead to conductive layers with good conductivity, in particular since this is not possible with diacyl peroxides. First, it is known that certain peroxidic compounds can oxidize thiophenes to sulfoxides and sulfones, i. h., there are no or only subordinate polythiophenes. (See, for example, Nakayama, Juzo, Nagasawa, Hidehiro, Sugihara,

Yoshiaki; IsMi, Akihiko, Journal of the American Chemical Society (1997), 119 (38), 9077-9078 or Nakayama, Juzo, Bulletin of the Chemical Society of Japan (2000), 73 (1), 1-17), also by EDT is known to react with peroxidic compounds to products other than polythiophenes, e.g. Thiolactones (Kirchmeyer, Stephan, Reuter, Knud, Journal of Materials Chemistry (2005), 15 (21), 2077-2088).

In addition, it is known from numerous papers that peroxidic compounds are capable of oxidizing alcohols to carbonyl compounds and / or carboxylic acids, whereas surprisingly according to the present invention, especially mixtures containing alcohols or alcohols in preferred embodiments are well suited solvents for the oxidative polymerization of the thiophenes ,

The oxidative polymerization of polythiophenes according to the inventive method can be used for different applications of the resulting thiophenes. For example, it is possible to use stable dispersions containing polythiophenes or else directly, i. by Uu polymerization to produce conductive layers containing polythiophenes, which are each accessible to numerous other applications.

The invention accordingly further provides the use of organic peroxide compounds except diacyl peroxides for the oxidative in-süu polymerization of thiophenes or their derivatives listed above or for the preparation of dispersions containing optionally substituted polythiophenes by oxidative polymerization of optionally substituted thiophenes or thiophene derivatives. Particularly preferred is the use of organic salts, in particular tetraalkylammonium salts, peroxodisulfuric acid. The latter are particularly well suited for in situ polymerization.

The present invention further provides a process for the preparation of dispersions containing optionally substituted polythiophenes by oxidative polymerization of optionally substituted thiophenes or thiophene derivatives in the presence of at least one solvent and optionally at least one counterion, characterized in that at least one organic peroxidic compound excluding diacyl peroxides as the oxidizing agent is used. For the polymerization, the thiophenes or their derivatives, oxdating agents and optionally counterions are preferably dissolved in the solvent or solvents and stirred at the intended polymerization temperature until the polymerization is complete.

The dispersions prepared may be aqueous or nonaqueous dispersions.

In a preferred embodiment, the solvent or solvents are nonaqueous solvents. In these non-aqueous dispersions may also contain minor proportions, that is, to be preferably less than 10 wt .-% ₃ contain water. In the non-aqueous dispersions, the optionally substituted polythiophenes and counterions may be present both partially and completely dissolved or dispersed. All these forms are preceded and im

The following are referred to as dispersions in the context of this invention.

Thiophenes and counterions, in particular in the case of polymeric counterions, are used in such an amount that the counterion (s) and polythiophene (s) are subsequently used in a weight ratio of from 0.5: 1 to 50: 1, preferably from 1: 1 to 30 : 1, more preferably 2: 1 to 20: 1. The weight of the polythiophene corresponds to the initial weight of the monomers used, assuming that complete conversion takes place during the polymerization.

The present invention also provides a process for the preparation of conductive layers containing optionally substituted polythiophenes, characterized in that optionally substituted thiophenes or thiophene derivatives in presence or absence of at least one solvent with at least one organic peroxide compound except diacyl peroxides as oxidizing agent on a suitable Underlay oxidatively polymerized.

The last-mentioned method-often referred to in the art as in-situ polymerization-is also used, for example, for producing layers which are constituents of capacitors, for example for producing the solid electrolyte or the electrodes.

The underlay can be, for example, glass, thin glass (flexible glass) or plastics to be coated in the form of shaped bodies or films and other shaped bodies to be coated, for example anodes of capacitors.

Depending on the application target for the polythiophenes synthesized by the process according to the invention, the use of different organic peroxidic compounds may be advantageous.

For example, water-soluble organic hydroperoxides are suitable for the preparation of aqueous dispersions containing the polythiophenes listed above. Preference is given here tert.- ~ 1 o ~

Butyl hydroperoxide. A particularly preferred dispersion which can be prepared according to this variant is an aqueous dispersion comprising poly (3,4-ethylenedioxythiophene) and polystyrenesulphonic acid (PEDT / PSS complex).

Organic peroxides which are soluble in nonaqueous solvents are particularly suitable for the preparation of nonaqueous dispersions or for the preparation in Yw polymerized polythiophene

Layers, preferably poly (3 _s 4-ethylenedioxythiophene) layers (PEDT layers), which are usually produced from organic solvents, if appropriate in the presence of suitable counterions or counterion-supplying acids.

In the above-mentioned processes for the preparation of dispersions and conductive layers, the already mentioned polythiophenes are obtained and can those already mentioned

Thiophenes and their derivatives, special organic peroxide compounds, counterions etc. can be used. Preferred ranges apply analogously.

Preferred non-aqueous solvents for the preparation of nonaqueous dispersions or in polythiophene polythiophene layers may be e.g. As alcohols such as methanol, ethanol n-propanol, isopropanol, n-butanol, ethylene glycol, diethylene glycol, of these alcoholic solvents, ethanol and n-butanol are particularly preferably used. But it can also solvents from the group of aliphatic and aromatic hydrocarbons, such as hexane, heptane, octane, toluene or xylene ₅ of the halogenated aliphatic or aromatic hydrocarbons ,, such as methylene chloride, chloroform, chlorobenzene or o-dichlorobenzene, furthermore ethers, such as diethyl ether, Di-iso-propyl ether, tert.Butylmethylether, tetrahydrofuran (THF), dioxane or diglyme, amides such as dimethylformamide, dimethylacetamide or N-methylpyrrolidone aHeine or used in a mixture with alcohols. To a small extent, ie preferably less than 5% by weight, water may also be present.

For the preparation of aqueous dispersions also small proportions, i. preferably less than 10% by weight, of the preceding solvents, in particular alcohols, in the water.

For the preparation of stable aqueous polythiophene dispersions, it is advantageous to use water-soluble counterions of the abovementioned, preferably sulfonic acids, in particular polymeric sulfonic acids, such as, for example, polystyrenesulfonic acid (PSS).

For the preparation of nonaqueous polythiophene dispersions or the in-situ production of

Layers of organic solution, it is advantageous to use sufficiently soluble in the solvent counterions, preferably sulfonic acids. These may advantageously be monomeric counterions such as, for example, p-toluenesulfonic acid, dodecylbenzenesulfonic acid or camphorsulfonic acid. The processes according to the invention can preferably be used for the production of solid electrolytes in capacitors. In principle, an electrolytic capacitor is produced as follows: First, for example, a powder having a high surface area is pressed and sintered into a porous electrode body. Metal foils may also be etched to obtain a porous foil. The electrode body is then coated, for example by electrochemical oxidation, with a dielectric, ie an oxide film. On the dielectric, the thiophene or thiophene derivative is polymerized by means of the oxidizing agent according to the invention to form a conductive polymer, which forms the solid electrolyte. A coating of highly conductive layers, such as graphite and silver, serves as an electrode to dissipate the current. When using porous films, these, as common with aluminum capacitors, even before the

Production of the solid electrolyte is wound together with a second metallic foil, which serves to conduct current. A separator film is placed between the two films during winding. Finally, the capacitor is contacted and encapsulated.

The electrode material preferably forms in the electrolytic capacitor a porous body having a large surface area, e.g. in the form of a porous sintered body or a roughened film. In the following, this is also referred to briefly as the electrode body.

The electrode body covered with a dielectric is also referred to below as the oxidized electrode body. The term "oxidized electrode body" also encompasses those electrode bodies that are covered with a dielectric that was not produced by oxidation of the electrode body.

The electrode body covered with a dielectric as well as completely or partially with a solid electrolyte is also referred to below for short as the capacitor body.

In addition to oxidizing agents, thiophene or thiophene derivatives, it is also possible to introduce counterions into the oxidized electrode body in order to form the solid electrolyte. Preference is given above monomeric or polymeric counter ions.

As a catalyst for the polymerization small amounts of transition metal ions are introduced into the oxϊ- derten electrode body, z. Fe, Co, Ni, Ce, V, Zr ions in the form of soluble salts (eg tosylates), preferably Fe-II, Fe-III, Co-II and Co salts. III ions. Another possibility for the catalytic acceleration of the peroxide reaction consists in the addition of small amounts of tert. Mines, z. B. known from the UP resin technology compounds such as N, N-dimethylaniline,

N, N-diethylaniline, the corresponding toluidines or chloroanilines and optionally also N, N-bis (hydroxyethyl) anilines and their polymeric derivatives.

The introduction of the oxidizing agent, the thiophene or thiophene derivative, optionally the counter ions and the catalyst is preferably carried out in mixtures containing one or more Solvent. However, all or parts of the polymerization educts, oxidizing agents, thiophene or thiophene derivative, optionally counterions and catalyst can also be introduced sequentially (sequentially) into the oxidized electrode body. Thus, for example, the oxidizing agent may first be introduced and, if appropriate after evaporation of the solvent, the thiophene or thiophene derivative introduced into the oxidized electrode body. The catalyst can be introduced in a separate step, for example before introduction of the oxidizing agent and thiophene or thiophene derivative, or together with one of the polymerization educts. The same applies to the counterions. In order to ensure a long shelf life of the mixture when using mixtures of oxidizing agent and thiophene or thiophene derivatives, it may be expedient to separate the catalyst into the oxidized one separately before mixing or after mixing

To introduce the electrode body.

The mixtures or educts which are introduced into the oxidized electrode body may also contain other components such as one or more organic solvents soluble in organic solvents such as polyvinyl acetate, polycarbonate, polyvinyl butyral, polyacrylic acid ester, polymethacrylic acid ester, polystyrene, polyacrylonitrile, polyvinyl chloride, polybutadiene, polyisoprene , Polyether, polyesters, silicones, styrene / acrylic ester, vinyl acetate / acrylic ester and ethylene / vinyl acetate copolymers or water-soluble binders such as polyvinyl alcohols, crosslinkers such as melamine compounds, blocked isocyanates, functional silanes - eg Tetraethoxysilane, alkoxysilane hydrolysates, e.g. based on tetraethoxysilane, epoxysilanes such as 3-glycidoxypropyltrialkoxysilane - polyurethanes, polyacrylates or polyolefin dispersions, and / or

Additives such as e.g. surfactants, e.g. ionic or nonionic surfactants or coupling agents, e.g. organofunctional silanes or their hydrolysates, e.g. 3- Grycidoxypropyltrialkoxysilane, 3-aminopropyltriethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-metacryloxypropyltrimethoxysilane, vinyltrimethoxysilane, octyltriethoxysilane.

The application may be directly or using a primer, such as a

Silanes, e.g. organofunctional silanes or their hydrolysates, e.g. 3-glycidoxypropyltriaoxoxysilane, 3-aminopropyltriethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-metacryloxypropyltrimethoxysilane, vinyltrimethoxysilane or octyltriethoxysilane, and / or one or more other functional layers on the dielectric of the electrode body erfoϊ gene.

The mixtures preferably contain from 1 to 30% by weight of the thiophene or thiophene derivatives and from 0 to 50% by weight of binders, crosslinkers and / or additives, both percentages by weight, based on the total weight of the mixture.

The mixture or the polymerization educts are prepared by known processes, for example by impregnation, casting, dripping, spraying, spraying, knife coating, brushing, spin coating or coating. printing, for example ink-jet, screen, contact or pad printing, applied to the oxidized electrode body.

After application of the mixture or Polyraerisationsedukte carried out to accelerate the polymerization, a thermal treatment at temperatures of -10 to 300 ⁰ C, preferably 10 to 200 ⁰ C, particularly preferably 30 to 15O ⁰ C. The duration of the heat treatment is dependent on the nature of polymer used for the coating for 5 seconds to several hours. Temperature profiles with different temperatures and residence times can also be used for the thermal treatment.

The heat treatment may e.g. be carried out in such a way that one moves the coated oxϊ- dierten electrode body at such a speed through a heat chamber located at the desired temperature that the desired residence time is achieved at the selected temperature, or with a hot plate located at the desired temperature for the brings desired residence time in contact. Furthermore, the heat treatment can be carried out, for example, in one heating furnace or several heating furnaces, each with different temperatures.

After the polymerization, it may be advantageous to wash out the excess oxidant and residual salts from the coating with a suitable solvent, preferably water or alcohols. By residual salts are meant, for example, the products of the reduction of the oxidizing agent and any salts present.

For metal oxide dielectrics, such as the oxides of the valve metals, it may, according to the

Polymerization and preferably be advantageous during or after the washing, e-lektrochemisch imitate the oxide film to mend any defects in the oxide film and thereby reduce the residual current of the finished capacitor. During this so-called reforming, the capacitor body is immersed in an electrolyte and a positive voltage is applied to the electrode body. The flowing current re-forms the oxide at defective points in the oxide film or destroys conductive polymer at defects over which a high current flows.

Depending on the type of oxidized electrode body, it may be advantageous to impregnate the oxidized electrode body before and / or after a washing process a further time with the mixtures or polymerization in order to achieve thicker polymer layers in the interior of the electrode body. The compositions of the mixtures or polymerization educts may be different. Optionally, the solid electrolyte may be constructed of a multilayer system comprising multiple functional layers.

After preparation of the solid electrolyte, it is optionally possible to apply further layers to the capacitor body. - -

The electrode material of the capacitor is preferably a valve metal or a compound with comparable properties.

In the context of the invention, metal metals are understood to be metals whose oxide layers do not allow current flow in both directions equally: With anodically applied voltage, the oxide layers of the valve metals block the flow of current, while with cathodically applied voltage large currents occur which destroy the oxide layer can. The valve metals Be, Mg, Al, Ge, Si, Sn, Sb include ₅ Bi, Ti, Zr, Hf, V, Nb, Ta and W and an alloy or compound of at least one of these metals with other elements. The best known representatives of the valve metals are Al, Ta, and Nb. Compounds with comparable properties are those with metallic conductivity, which are oxidizable and whose oxide layers have the properties described above. For example, NbO has metallic conductivity but is generally not considered a valve metal. However, layers of oxidized NbO have the typical properties of metal oxide vapor layers such that NbO or an alloy or compound of NbO with other elements are typical examples of such compounds with comparable properties.

Accordingly, the term "oxidizable metal" includes not only metals, but also an alloy or compound of a metal with other elements as long as they have metallic conductivity and are oxidizable.

Particularly preferred valve metals or compounds having comparable properties are tantalum, niobium, aluminum, titanium, zirconium, hafnium, vanadium, an alloy or compound of at least one of these metals with other elements, NbO or an alloy or compound of NbO with other elements.

The dielectric preferably consists of an oxide of the electrode material or - if this is already an oxide - a more highly oxidized form of the electrode material. It optionally contains further elements and / or compounds.

For example, the oxidizable metals are sintered into a porous electrode body in powder form, or a porous structure is impressed on a metallic body. The latter can e.g. by etching a foil.

The porous electrode bodies are used, for example, in a suitable electrolyte, e.g. Phosphoric acid, oxidized by applying a voltage. The height of this forming voltage depends on the oxide layer thickness to be achieved or the subsequent application voltage of the capacitor. Preferred voltages are 1 to 300 V, more preferably 1 to 80V.

Due to their low residual current and their low ESR, the electrolytic capacitors produced by the process according to the invention are outstandingly suitable as components in electronic see circuits. Preference is given to digital electronic circuits, as used, for example, in computers (desktop, laptop, server), in portable electronic devices, such as mobile phones and digital cameras, in consumer electronic devices, such as in CD / DVD players and computer game consoles, in navigation systems, and in Telecommunications facilities are located.

Further subject of the present invention are therefore Elektrorytkondensatoren prepared by the method according to the invention, and the use of these electrolytic capacitors in electronic circuits.

The following examples serve to exemplify the invention and should not be construed as limiting.

Examples

Example 1

In ^ / ^ - polymerization of 3 ₇ 4-ethylenedioxythiophene (EDT) with tert-butyl hydroperoxide and di-tert-butyl peroxide as the oxidant

0.41 g of a 10% solution of tert-butyl hydroperoxide in ethanol, 0.17 g of a 15% solution of di-tert-butyl peroxide in ethanol, 0.8 g of a 10% solution of EDT in ethanol, 1, 43 g of a 30% strength solution of p-toluenesulfonic acid monohydrate in ethanol and 0.48 g of a 0.5% solution of iron (III) toluenesulfonate in ethanol were mixed and knife-coated onto a polycarbonate film with a wet film thickness of 12 μm. After 1 h of drying at 85 ⁰ C was briefly washed with water; thereafter, a conductive blue film having a surface resistance of 25.7 kΩ / sq was obtained.

Example 2

In s / ftf polymerization of 3,4-ethylenedioxythiophene (EDT) with tert-butyl hydroperoxide as the oxidant

0.18 g of a 5.5 molar solution of tert-butyl hydroperoxide in nonane, 0.5 g of a 20% solution of EDT in ethanol, 1.07 g of a 50% solution of p-toluenesulfonic acid monohydrate in ethanol and 0 , 60 g of a 1% solution of iron (III) toluenesulfonate in ethanol were mixed and knife-coated at 12 μm wet film thickness onto a polycarbonate film. After 1 h drying at 85 ⁰ C was briefly washed with water; thereafter, a conductive blue film having a surface resistance of 1.63 kΩ / sq was obtained.

Example 3

In J7? M polymerization of EDT with tetra-n-butylammonium peroxodisulfate as the oxidant

0.60 g of tetra-n-butylammonium peroxodisulfate, J), 5 g of a 20% solution of EDT in ethanol, 1.33 g of a 50% solution of p-toluenesulfonic acid monohydrate in ethanol and 0.34 g of a 1% solution of iron (III) toluenesulfonate in ethanol was mixed and knife-coated with 12 μm wet film thickness onto a polycarbonate film. After 1 h drying at 85 ⁰ C was briefly washed with water; thereafter, a conductive blue film having a surface resistance of 5.37 kΩ / sq was obtained. Example 4

Polymerization of EDT in organic solution with a perester as oxidant

97 g of xylene, 9 "21 g dinonylnaphthalenesulfonic acid, 0.71 g ethylenedioxythiophene (EDT) and 1.36 g peroxybenzoic acid tert-butyl ester (tert-butyl peroxybenzoate) were stirred intensively in a flask at 23 ⁰ C. The mixture is treated with a drop of a 60% solution of Eiseii (IΪI) p-toluenesulfonate in butanol and discolored in a short time purple to blue. The mixture is stirred for 4 h and then treated with a further 332 g of xylene. After stirring for a further 2 hours, the mixture is filtered through a fluted filter. The product obtained is a dark blue solution / dispersion and a dark blue precipitate. A pressure of the precipitate shows an electrical conductivity of 3 x 10 ^"7 S / cm. The filtered solution can be knife coated as a moderately conductive film on glass.

Comparative Example 1 onsmittel

0.85 g of a 40% solution of dibenzoyl peroxide in dibutyl phthalate, 0.8 g of a 20% strength

Solution of EDT in ethanol, 2.13 g of a 50% solution of p-toluenesulfonic acid monohydrate in ethanol and 0.11 g of a 5% solution of iron (III) toluenesulfonate in ethanol were mixed and 12 m wet film thickness to a Polycarbonate film scrape on. After drying at 85 ^° C. it was washed out briefly with water; after that, a streaky gray irregular film was obtained. It could not be measured due to the irregularity of the film no conductivity.

The comparative example clearly shows that dibenzoyl peroxide is not suitable as an oxidizing agent for the in-situ deposition of polythiophenes.

Comparative Example 2:

In. » ^' /« - Polymerization of 3,4-ethylenedioxythiophene (EDT) with dibenzoyl peroxide as oxidant

1.04 g of a 15% solution of 75% dibenzoyl peroxide (balance, water) in acetone, 0.5 g of a 10% solution of EDT in ethanol, 1.34 g of a 20% solution of p-toluenesulfonic acid Monohydrate in ethanol and 0.3 g of a 0.5% solution of iron (III) toluenesulfonate in ethanol were mixed and knife-coated at 12 μm wet film thickness onto a polyethylene terephthalate film. After 1 hour drying at 85 ⁰ C was ausgewa- briefly with water - - see; thereafter, an irregular, striped blue-gray film having a surface resistance of 2320 kΩ / sq was obtained.

Claims

- -

Patent applications

Process for the preparation of polythiophene dispersions or for the in-situ deposition of polythiophenes by means of oxidative polymerization of thiophenes or thiophene derivatives, characterized in that at least one organic peroxidic compound except diacyl peroxides is used as the oxidizing agent.

Process according to Claim 1, characterized in that polythiophenes containing recurring units of the general formula (I)

wherein

R ¹ and R ² are each independently H, an optionally substituted Ci-Ci ₈ ~ alkyl or an optionally substituted C] -Cj ₈ - alkoxy, or

R ¹ and R ² together represent an optionally substituted Ci-Cg-alkylene radical, an optionally substituted QQ-alkylene radical, wherein one or more C-atom (s) may be replaced by O, preferably a C ₁ -Cg-Dioxyalkylenrest or for a optionally substituted propen-1,3-diyl, in which optionally the C-3 atom may be replaced by a heteroatom selected from O or S,

by oxidative polymerization of thiophenes of the general formula (II),

wherein R ¹ and R ^{2 have} the meaning given for the general formula (ϊ),

getting produced. - -

3. The method according to claim 1 or 2, characterized in that polythiophenes containing recurring units of the general formula (I-a) and / or (I-b)

wherein

A is an optionally substituted C ₁ -C ₅ -alkylene radical, preferably an optionally substituted C ₂ -C ₃ -alkylene radical,

Y stands for O or S,

R is a linear or branched, optionally substituted CrCjg-alkyl radical, an optionally substituted Cs-Cπ-cycloalkyl radical, an optionally substituted Q-Cn-aryl radical, an optionally substituted Cv-Qg-aralkyl radical, an optionally substituted Ci-G $ -Hydroxyalkylrest or a hydroxyl radical,

x is an integer from 0 to 8, preferably 0 or 1, and

by oxidative polymerization of thiophenes of the general formula (II-a) and / or (II-b),

(II-a) (II-b) wherein A, Y, R and x are as defined for general formulas (II-a) and (II-b),

getting produced.

4. The method according to at least one of claims 1 to 3, characterized in that poly (3,4-ethylenedioxythiophene) is prepared by oxidative polymerization of 3,4-ethylenedioxythiophene.

5. The method according to at least one of claims 1 to 4, characterized in that the oxidizing agent used are organic peroxidic compounds in which at least one grouping -O-O- is contained.

6. The method according to at least one of claims 1 to 5, characterized in that are used as the oxidizing agent organic peroxidic compounds such as dialkyl peroxides, alkyl hydroperoxides, peracids, Aikylpercarboxylate or alkyl percarbonates.

7. The method according to at least one of claims 1 to 5,. characterized in that organic salts of peroxydisulphuric acid or Caro's acid are used as the oxidizing agent.

8. The method according to claim 7, characterized in that the organic salt used is an organically substituted ammonium or phosphonium salt of peroxodisulfuric acid.

9. The method according to claim 8, characterized in that a mono-, di-, tri- or tetraalkylammonium salt of peroxodisulfuric acid is used.

10. The method according to claim 9, characterized in that as the ammonium salt bis (tetra-n-butylammonium) peroxodisulfate [(nC ₄ H ₉ ) ₄ N] ₂ S ₂ θ ₈ is used.

11. The method according to at least one of claims 1 to 6, characterized in that the oxidative polymerization is carried out in the presence least of a solvent.

12. The method according to at least one of claims 1 to 7, characterized in that the oxidative polymerization is carried out in the presence least of a counterion.

13. The method according to at least one of claims 1 to 8, characterized in that the oxidative polymerization at temperatures of -10 to 250 ⁰ C is performed.

14. The method according to at least one of claims 1 to 9, characterized in that thiophenes and oxidizing agents in a weight ratio of 4: 1 to 1: 20 are used.

15. A process for preparing dispersions containing optionally substituted polythiophenes by oxidative polymerization of optionally substituted thiophene or thiophene derivatives in the presence of at least one solvent and optionally at least one counterion, characterized in that as Ox dationsmittel at least one organic peroxidic compound is used.

16. A process for the preparation of conductive layers containing optionally substituted Polylhiophene, characterized in that optionally substituted thiophenes or

Thiophene derivatives in the presence or absence of at least one solvent with at least one organic peroxidic compound as an oxidizing agent are oxidatϊv polymerized on a suitable surface.

17. The method according to claim 16, characterized in that the leitfohige layer is part of a capacitor.

18. The method according to claim 16 or 17, characterized in that the conductive layer is a solid electrolyte.

19. Electrolytic capacitors containing a component obtainable by the process according to at least one of claims 16 to 18.

20. Use of the electrolytic capacitor according to claim 19 in electronic circuits.