DE4332964A1 - High mol. wt. aromatic polyetherketone prodn. - by reacting aromatic diol with aromatic dihalo cpd. in presence of phase transfer catalyst, esp. a pyridinium cpd. - Google Patents

Abstract

In the prodn. of polyetherketones by reaction of an aromatic dihydroxy cpd. of formula HO-Ar-OH (I) with an aromatic dihalo cpd. of formula Hal-Ar2-Co-Ar3-Hal (II) at elevated temp. in an aprotic-polar solvent in presence of an alkali metal carbonate, a phase transfer catalyst is present. (where Ar = phenylene, 10-30C condensed aromatic gp. or 2-5 phenylene gps. bonded via single bonds, (thio) ether bridges, carbonyl gps., sulphone gps. or methylene gps. (opt. with H replaced by 1-5C alkyl), the aromatic rings being opt. substd. by 1-4C alkyl, NO2, Cl and/or Br, with the proviso that no one ring is substd. by halogen and NO2 at the same time; Hal = Cl and/or F; and Ar2 and Ar3 = 6-24C aromatic gps. with Ar3 also opt. being a no. of phenylene rings connected viz. one or more carbonyl or sulphonyl gps. and opt. also (thio)ether gps., with both Hal in p- or o-position to a -CO- and/or -SO2- gp.). ADVANTAGE - High mol. wt. amorphous or partially crystalline polymers are obtd. in high space-time yield using easily-obtd. bischloroaryl ketones.

Description

The present invention relates to a process for the production of aromatic Polyether ketones by polycondensation of aromatic Hydroxy compounds with chloro or fluoroaryl ketones using Phase transfer catalysts.

Aromatic polyethers, the aromatic units of which are polar functional Groups (e.g. keto or sulfone groups) are linked in the last Years of increasing importance due to their outstanding properties numerous areas. You can mainly use two procedures getting produced:

In the so-called electrophilic process, aromatic acyl halides and aromatic ethers are polymerized according to the mechanism of Friedel-Crafts acylation in the presence of Lewis acids such as AlCl ₃ or BF ₃ as catalysts and dichloromethane / DMF or HF as solvents. A disadvantage of this process is that the inclusion of metal salts in the polymer cannot be ruled out and defects in the polymer occur due to ortho substitution.

The synthesis of aromatic polyether ketones can also by nucleophilic Substitution take place. Aromatic dihydroxy compounds are used aromatic dihalogen compounds in the presence of acid-binding Agents, especially alkali metal carbonates, according to the following Reaction equation implemented:  

in this equation, M represents an alkali metal cation, X represents a halogen atom, Ar an aromatic radical and Ar 'a bisaromatic radical, the at least contains an electron-withdrawing bridge.

Semi-crystalline aromatic polyether ketones are known. R.N. Johnson, R. A. Clendinning, A. G. Farnham, W. F. Hall, C. N. Merriam, J. Polym. Sci., Part A-1, Vol. 5, 2375 (1967) examined the reactivity of many activated ones aromatic dihalides in the reaction with an alkali metal salt of Bisphenol A with dimethyl sulfoxide as solvent. They found that activated Difluoride compared to the corresponding dichlorides much more reactive are and moreover higher molecular weights can be achieved.

In US 4010147, for example, the reaction of the di-alkali salt is one aromatic dihydroxy compound, optionally a keto group can contain, with an activated aromatic dichloro compound in Presence of an aromatic sulfone as a solvent at 250-400 ° C described. The implementation is slow. The analog difluoro compounds react faster. Another method is based on the implementation of a Hydroxy-halogen derivative of benzophenone or diphenyl sulfone with Alkali carbonate or alkali bicarbonate in the presence of N-methylpyrrolidinone or an aromatic or aliphatic sulfone at 200 ° C to 400 ° C (e.g. U.S. Patent 4,113,699).

From EP-B-182 648 it is known that the alkaline polycondensation of Halogenphenols, such as 4-chloro-4'-hydroxybenzophenone, by Copper compounds is favored. In the absence of copper or at the  Preparation of the same polymer from 4,4'-dichlorobenzophenone and 4,4'-bihydroxybenzophenone produces products with significantly lower inherent viscosity (lower molecular weight).

In these processes for the production of partially crystalline polyether ketones The method of nucleophilic aromatic substitution has so far mostly been used Difluoroarylketone such as. B. 4,4'-difluorobenzophenone used (see. EP-A 1 879, US 4010147). The analog and more accessible Chloromonomers have so far not been able to achieve a satisfactory result economic production of polyether ketones are used.

According to PM Hergenrother, BJ Jensen, SJ Havens, Polymer, 29, 358 (1988), amorphous and therefore soluble and partly crystalline polyaryl ether ketones can be prepared using bischloro and bisfluoroaromatics. The reaction time was 16 hours at 155 ° C. The polymer obtained in the reaction of bisphenol A with 1,4-bis (chlorobenzoyl) benzene in the presence of K ₂ CO ₃ in dimethylacetamide had only an inherent viscosity (chloroform, 0.1%, 20 ° C.) of 0. 68 dl / g. The glass temperature was 166 ° C. Bisfluoroaromatics led to polymers which have a significantly higher inherent viscosity than the polymers obtained from the analogous bischloroaromatics.

The object was to provide a process which was economical Preparation of aromatic polyether ketones with high space-time yields allowed using easily accessible bischloraryl ketones. In particular, polymers with a high molecular weight should be accessible become.

There has now been a process for the preparation of aromatic polyether ketones, found in which an aromatic dihydroxy compound of general formula I.

HO - Ar - OH (1)

in which Ar is phenylene or a condensed aromatic radical with 10-30 C atoms or Ar consists of two to five phenylene rings which are formed by single bonds, ether bridges, thioether bridges, carbonyl groups, sulfone groups or methylene groups, the H atoms of which are represented by C ₁ -C ₅ Alkyl groups can be replaced, are connected to one another,
the hydrogen atoms bonded to aromatic rings can be replaced in whole or in part by C ₁ -C ₄ alkyl, nitro, chlorine and / or bromine, with the proviso that an aromatic ring is not substituted by halogen and nitro at the same time,
at elevated temperature in an aprotic polar solvent in the presence of alkali metal carbonate, an aromatic dihalo compound of the general formula II

Hal - Ar ² - CO - Ar ³ - Hal (II)

in which Hal represents chlorine and / or fluorine, Ar ² and Ar ^{3 are} aromatic radicals each having 6-24 C atoms, the rest Ar ^{3 can} also consist of several phenylene rings, which are substituted by at least one carbonyl group or sulfonyl group and optionally by Ether groups or thioether groups are connected to one another, and the two Hal radicals are each arranged in the para position or ortho position to a CO and / or SO ₂ group.

This process is characterized in that the reaction in In the presence of a phase transfer catalyst.

The molar ratio I: II is preferably from 0.9: 1 to 1: 0.9.  

The process according to the invention succeeds in amorphous and partially crystalline To produce polyether ketones. The products obtained show high Molecular weight, high stability against chemicals, high temperature stability as well as good mechanical properties.

It has already been observed that in the field of low molecular weight Chemistry the use of a phase transfer catalyst is advantageous.

D.J. Brunelle, D.A. Singleton; Tetrahedron Letters, 25, 3383 (1984) deals in the field of low molecular weight chemistry with etherification reactions of phenols and thiophenols with less activated halogen aromatics such as 4-chloro-nitrobenzene or bis-4-chlorophenyl benzophenone and benzosulfone. they could show that with the addition of N-alkyl-4-N ', N'-dialkylamino-pyridinium salt the yields of ether products is almost quantitative. It will indicated that the catalysts used up to a temperature of 300 ° C are thermally stable and the catalyst slowly from Na phenoxide and also attacked by sodium hydroxide.

However, it is completely surprising that these phase transfer catalyst systems the nucleophilic conversion of dihydric phenols with activated Accelerate bis-halogen aromatics for the production of polymers and above also allow the use of bischlor derivatives.

The amount of alkali metal carbonate added is not critical. 1 to 2 moles of alkali metal carbonate per mole of the aromatic dihydroxy compound of the general formula (I) are preferred. The alkali metal carbonates of lithium, sodium, potassium, cesium and rubidium are suitable. Sodium or potassium carbonate are particularly preferred. In addition, there are also base combinations consisting of at least one alkali metal carbonate (e.g. Li ₂ CO ₃ , Na ₂ CO ₃ , K ₂ CO ₃ ) and at least one further alkali compound (e.g. Li salt, Na salt, K Salt) from the group of alkali metal hydroxides and bicarbonates.

Preferred solvents in the process according to the invention Dimethylacetamide, dimethyl sulfoxide, N-methyl-2-pyrrolidone and diphenyl sulfone used and particularly preferably dimethylacetamide and diphenyl sulfone.

Phase transfer catalysts can be used in the process according to the invention for example, quaternary ammonium salts of the general formula III are used will,

in which A⁻ for the counterion, e.g. B. fluoride, chloride, methyl sulfate, methyl sulfonate, mesilate, tosylate and the radicals R ¹ , R ² , R ⁹ and R ^{10 are} phenyl substituents or alkyl substituents, in particular C ₁ -C ₁₆ alkyl substituents.

The amount of phase transfer catalyst to be added is not critical. Is preferred per mole of the aromatic dichloro compound of the general Formula (II) 0.01 to 0.1 mol of the phase transfer catalyst added.

The dichloroaryl ketones are easier and cheaper to produce than the others used difluoro analogs and prove to be among those according to the invention Reaction conditions as sufficiently reactive. The corresponding Bisfluoro compounds of the general formula (II) are more reactive, however more difficult to manufacture than the corresponding dichloro compound general formula (II). However, it is possible to use aromatic dichloro compounds of the general formula (I) at elevated temperature in the presence of a dipolar organic solvent in the presence of finely divided Alkali fluoride and phase transfer catalyst at least partially below  Implement halogen exchange to fluorinated compounds. In one variant the process of the invention is therefore the aromatic Dichloro compound of the general formula (II) in the presence of Alkali metal fluoride (and phase transfer catalyst) with the dihydroxy compound (I) implemented. In this variant, fluoride acts as a catalyst. The addition to Alkali metal fluoride can therefore be very low. It is preferably 0.01 to 0.1 mole per mole of dichloro compound of the general formula II.

According to a further embodiment of the method according to the invention first the aromatic dichloro compound of the general formula II with the at least equivalent amount of an alkali metal fluoride for at least 5 hours at elevated temperature in the presence of a phase transfer catalyst in one aprotic polar solvents react and only then sets the aromatic Dihydroxy compound of the general formula (I) and the alkali metal carbonate added. The aromatic dihydroxy compound is preferably added to the General formula (I) successively added and heated the batch to one a viscous solution has formed, d. H. the desired polymer has arisen. The phase transfer catalyst favors the implementation of the Dichloro compound with alkali metal fluoride as well as the later implementation of Dihydroxy compound.

For the process according to the invention can be used as dihydroxy compounds preferably the following dihydroxy compounds of the general formula I. can be used:

Mononuclear compounds such as hydroquinone, multinuclear dihydroxy compounds such as 4,4'-dihydroxybiphenyl, 4,4'-dihydroxydiphenyl ether, 2,2-bis-4- (hydroxyphenyl) propane, 2,2-bis-4- (hydroxyphenyl) methane, 4,4'-dihydroxybenzophenone, 4,4'-dihydroxydiphenyl sulfide, 4,4'-dihydroxydiphenyl sulfone, 1,4-bis (4-hydroxybenzoyl) benzene, 1,3-bis (4-hydroxybenzoyl) benzene, and each their core-substituted derivatives, in which the H atoms of the core are replaced by C ₁ -C ₄ alkyl groups, chlorine and / or bromine atoms or nitro groups. Simultaneous substitution of a nucleus by nitro and halogen groups, which could lead to activation of the halogen group, is not desirable.

2,2-bis (4-hydroxyphenyl) pentane, 2,2-bis (4-hydroxyphenyl) are preferred heptane, 2,2-bis (4-hydroxyphenyl) pentane and hydroquinone.

As examples of dihydroxy compounds with a condensed aromatic The rest are 1,4-dihydroxynaphthalene, 1,5-dihydroxynaphthalene and 1,5- Dihydroxyanthracene listed.

A pyridinium salt is preferably used as the phase transfer catalyst general formula IV uses

in which
Z is hydrogen, R ³ , R ³ R ⁴ N or R ⁵ R ⁶ N
R ³ and R ^{4 are} independently C ₁ -C ₆ alkyl or
R ³ and R ⁴ together form an alkylene group with 4 to 10 C atoms, which forms a saturated 5 or 6 ring with the N atom,
R ⁵ and R ^{6 are} phenyl rings' which can be substituted independently of one another by C ₁ -C ₄ alkyl, halogen or nitro groups, RC ₁ -C ₅ alkyl or a phenyl ring which is substituted by C ₁ -C ₄ alkyl, halogen or nitro groups can be,
X and Y independently of one another hydrogen, C ₁ -C ₄ alkyl or R ⁷ R ⁸ N
R ⁷ and R ^{8 are} phenyl rings which can be substituted independently of one another by C ₁ -C ₄ alkyl, halogen or nitro groups, and
A is a preferably monovalent anion, e.g. B. chloride, iodide or methyl sulfonate mean.

The compounds are very particularly suitable as phase transfer catalysts N-neopentyl-4- (dibutylamino) pyridinium chloride, N-neopentyl-4- (dihexylamino) pyridinium chloride and N-NeopentyI-4- (4'-methylpiperidinyl) pyridinium chloride.

Preferred dihalogen compounds are represented by the formulas (V), (VI), (VII) shown

in which Hal means chlorine and / or fluorine
Z represents an ether group, a thioether, a carbonyl group or a sulfonyl group, and
m and n independently of one another represent the numbers 1, 2 or 3.

Suitable aromatic dihalo-keto compounds are e.g. B. 4'4-dichlorobenzophenone, 2,4'-dichlorobenzophenone, 1,4-bis- (4-chlorobenzoyl) benzene, 1,3-bis (4-chlorobenzoyl) benzene, 4'4'-bis (4-chlorobenzoyl) biphenyl and 4,4'-bis (4-chlorobenzoyl) diphenyl ether.

Dichloraryl ketones of the formula (II) preferably have the chlorine substituent in para position at the terminal aromatic nucleus.

Particularly preferred dihaloaryl ketones are 4,4'-dichlorobenzophenone and 1,4-bis (4-chlorobenzoyl) benzene.

The reaction of bis- (chlorobenzoyl) benzene with bis- (4-hydroxyphenyl) pentane leads to a product with a molecular weight M _w = 124,200 in the absence of a phase transfer catalyst. However, the reaction requires a reaction time of 17 h. With the addition of 5 mol% (based on the chlorine compound) of a phase transfer catalyst (PTC 1), the molecular weight increases to 179 200 and it takes only 7 hours. If the addition of phase transfer catalyst is increased to 10 mol%, the required reaction time drops to 4.5 h and the molecular weight of the polymer obtained increases further to 195,300. If the chlorine compound is replaced by the analog bis-fluorine compound, Catalysis is no longer necessary (but possible): after only 2 h, a polymer with a molecular weight of 222,450 is available.

The process of the invention is first preferably at 155-230 ° C. carried out. The water of reaction formed from the alkali carbonate can be distill off with an entrainer. After the elimination of water the reaction mixture for a further 1-24 hours, preferably 2-10 hours Maintained 155-350 ° C. To achieve high molecular weights, the aromatic dihydroxy compounds with the dihaloaryl ketones in about equimolar amounts reacted with each other.

As an azeotropic entrainer, compounds can be used with Form an azeotrope and have a lower boiling point than that solvents used, for example benzene, toluene, xylene, etc., preferably have toluene.

The amorphous polymers obtained are soluble in THF, chloroform and Methylene chloride.

The invention is illustrated by the examples.

In Examples 1 to 4, no fluoride is added.

example 1

0.05 mol of 1,4-bis (chlorobenzoyl) benzene, 0.05 mol of 2,2-bis (4-hydroxyphenyl) pentane, 0.12 mol of K ₂ CO ₃ and 2.5 mmol of N-neopentyl 4- (dibutylamino) pyridinium chloride (= PTC I) are placed in a 250 ml reaction vessel with mechanical stirrer and gas inlet and outlet device in 100 ml of dimethylacetamide and 35 ml of toluene. The reaction mixture is then heated in a stream of argon to the reaction temperature of 155 ° C., whereupon the toluene-water azeotrope is distilled off. After a reaction time of 7 hours, the mixture is highly viscous. The polymer is precipitated by pouring the still hot mixture into methanol and the polymer is purified by reprecipitation from chloroform solutions. The polymer thus obtained has an inherent viscosity of 0.94 dl / g (chloroform, 0.1% solution, 25 ° C) and has a glass transition temperature of 158 ° C.

Example 2

The procedure is as in Example 1, but 0.05 mol of 2,2-bis- (4- hydroxyphenyl) propane, 0.1 mol potassium carbonate and 2.5 mol N-neopentyl-4- (dihexylamino) pyridinium chloride (= PTC II) used. After 7.2 hours the mixture is highly viscous. Pour into an acetic acid / water Mix and then washes the polymer in methanol. That so The polymer obtained has a glass transition temperature of 166 ° C.

The inherent viscosity determined in chloroform (0.1% solution) is 0.88 dl / g.

Example 3

The procedure is analogous to Example 1, but 0.05 mol of 2,2-bis- (4- hydroxyphenyl) heptane and 5 mmol N-neopentyl-4- (4′methylpiperidinyl) pyridinium chloride (= PTC III) used. The inherent viscosity was 1.23 dl / g (chloroform, 0.1% solution, 25 ° C), the reaction time 4.5 hours.

Example 4

0.05 mol 1,4-bis (chlorobenzoyl) benzene, 0.05 mol 4,4′- Bishydroxydiphenyl ether, 0.06 mol sodium carbonate, 2.5 mmol PTC 1 and 40 g Diphenyl sulfone as solvent are in a 250 ml reaction vessel submitted. After multiple evacuation and venting of the equipment with argon the reaction mixture is heated to 200 ° C and three to eight hours kept at this temperature. Then heated to 270 ° C to 300 ° C. To  The mixture becomes very viscous for about 60 to 180 minutes. You give as Stop reagent 4-fluorobenzophenone and let cool. That froze The mixture is ground and then alternately with acetone and water washed and finally dried at 100 ° C. The inherent viscosity of 0.80 dl / g was determined on 0.1% sulfuric acid solution. That so produced polymer is semi-crystalline with a glass transition temperature of 156 ° C and a melting temperature of 347 ° C.

In Examples 5 to 9 the reaction takes place in the presence of alkali fluoride

Example 5

The polycondensation is the same as in Example 1, but with a Catalyst mixture of 2.5 mmol PTC I and 0.125 mmol KF. The reaction was complete after a reaction time of 5 hours. The measurement the inherent viscosity in chloroform (0.1% solution) gave a value of 0.97 dl / g. The glass transition temperature Tg was 160 ° C.

Example 6

The procedure is analogous to Example 2, but with a catalyst mixture 2.5 mmol of PTC II and 0.15 mmol of KF are used to obtain one Reaction time of 5.2 hours for a polymer with an inherent viscosity of 0.88 dl / g (chloroform, 0.1% solution, 25 ° C). Tg = 165 ° C.

Example 7

The procedure of Example 3 is followed, but a catalyst mixture is used 2.5 mmol PTC I and 0.125 mmol KF are used after 5 hours  Response time of a polymer with an inherent viscosity of 0.92 dl / g (0.1% Chloroform solution).

Example 8

0.05 mol of 1,4-bis (4-chlorobenzoyl) benzene, 0.06 mol of potassium carbonate, 5 mmol PTC I, 4 mmol KF and 40 g diphenyl sulfone are in a 250 ml Face grinding reaction vessel with mechanical stirrer, gas inlet and outlet device and heatable dropping funnel presented. They are evacuated Equipment and aerated with argon. The reaction mixture is at 200 ° C in Argon flow heated. Then 0.049 mol of hydroquinone, which is in 20 g Diphenyl sulfone was dissolved, added dropwise. The reaction temperature will then increased to 250 ° C. After 2-4 hours the temperature will rise 280 ° C-320 ° C increased. Allow the viscous solution to cool, grind that solidified mixture in an analytical mill and washed alternately with acetone and water. The inherent viscosity of the polymer thus purified, in Measured sulfuric acid is 0.9 dl / g. The polymer has one Glass temperature of 160 ° C and a melting temperature of 358 ° C.

In Examples 9 and 10 there was a two-step reaction.

Example 9 Level A

0.05 mol of 1,4-bis (chlorobenzoyl) benzene, 0.05 mol of KF and 2.5 mmol of PTC I are placed in 100 ml of dimethylacetamide and about 10 hours at 165 ° C. touched.

The halogen exchange of chlorine for fluorine, which NMR spectroscopic has been demonstrated, provides fluorinated substitution products of  1,4-bis (chlorobenzoyl) benzene. In the 1,4-bis (chlorobenzoyl) benzene used 30% of the chlorobenzoyl groups were replaced by fluorobenzoyl groups.

Level B

A reaction product prepared according to stage A is 0.05 mol 2,2-bis (4-hydroxyphenyl) heptane, which was dissolved in 30 ml of toluene, dripped. The reaction mixture is heated to 155 ° C. in a stream of argon. After 4 hours of reaction time, a polymer with an inherent Viscosity of 0.83 dl / g obtained (determined from 0.1% chloroform solution 25 ° C).

Example 10 Level A

The procedure is analogous to Example 9 (stage A), but 0.05 mol 4,4'-dichlorobenzophenone used, the content of fluorinated Substitution products by the halogen exchange reaction about 35%.

Level B

The reaction mixture obtained after step A of this example is analogous Example 10 (step B), but using 0.05 mol 2,2-bis (4-hydroxyphenyl) propane. It becomes a polymer with a inherent viscosity of 0.95 dl / g obtained. The response time is 4 Hours. The glass temperature is 155 ° C.

Comparative Examples 1-3 One-step reactions Comparative Example 1

If the procedure is analogous to Example 1, but without the presence of PTC I, the procedure is as follows a polymer with an inherent viscosity of 0.72 dl / g (chloroform, 25 ° C) obtained after a reaction time of over 17 hours.

Comparative Example 2

The procedure is analogous to Example 2, but without the addition of PTC II Polymer with an inherent viscosity of 0.62 dl / g (measured in Chloroform at 25 ° C) only forms after a reaction time of 18 hours.

Comparative Example 3

The analogous procedure as in Example 3, but without PTC III, delivers polymeric material with an inherent viscosity of 0.94 dl / g (in chloroform measured) after a reaction time of 19 hours.

Comparative Example 4 (Halogen Exchanger in the Starting Product)

If step A is carried out as in Example 9, but no PTC I is added, then no halogen exchange reaction on 1,4-bis (chloropbenzoyl) benzene to prove.

Example 11 (Preparation of a starting product) 2,2-bis (4-hydroxyphenyl) pentane (= BPP)

A mixture of 0.05 mol 2-pentanone, 2 mol phenol and 0.005 mol Mercaptoacetic acid was saturated with HCl gas. The red mixture was Stirred for 24 h at room temperature in an argon atmosphere. Then the  Reaction mixture poured into hot water and the unused Starting components removed by steam distillation. Recrystallize from toluene gave a colorless solid product with mp in 90% yield. 147 ° C.

¹ H-NMR (200 MHz, DMSO-d ₆ , δ / ppm): 9.11 (s, 2H, -OH), 6.82 (AB system, 8H), 1.92 (m, 2H, methylene) , 1.45 (s, 3H, methyl), 1.05 (m, 2H, methylene), 0.85 (t, 3H, methyl)

Example 12 (Preparation of a starting product) 2,2-bis (4-hydroxyphenyl) heptane (= BPH)

The synthesis is carried out analogously to Example 11 (BPP). The yield of colorless purified product was 85%. The mp was 136 ° C.

¹ H-NMR (200 MHz, DMSO-d ₆ , δ / ppm): 9.08 (s, 2H, -OH), 6.81 (AB system, 8H), 1.92 (m, 2H, methylene) , 1.45 (s, 3H, methyl), 1.25 (m, 2H, methylene), 1.05 (in, 2H, methylene), 0.84 (t, 3H, methyl).

Claims (8)

1. A process for the preparation of polyether ketones by reacting an aromatic dihydroxy compound of the general formula I HO - Ar - OH (1) in which Ar is phenylene or a condensed aromatic radical having 10-30 C atoms or Ar from two to five phenylene rings consists of single bonds, ether bridges, thioether bridges, carbonyl groups, sulfone groups or methylene groups, the H atoms of which can be replaced by C ₁ -C ₅ alkyl groups,
where the hydrogen atoms bonded to aromatic rings can be replaced in whole or in part by C ₁ -C ₄ alkyl ₁ nitro, chlorine and / or bromine, with the proviso that an aromatic ring is not simultaneously substituted by halogen and nitro,
with an aromatic dihalogen compound of the general formula IIHal - Ar ² - CO - Ar ³ - Hal (II) in which Hal represents chlorine and / or fluorine, Ar ² and Ar ^{3 are} aromatic radicals each having 6-24 C atoms, the Ar ³ radical can also consist of several phenylene rings which are connected to one another by at least one carbonyl group or sulfonyl group and optionally by ether groups or thioether groups, and the two Hal radicals are each in the para position or ortho position to a CO and / or SO ₂ group are arranged, at elevated temperature in an aprotic polar solvent in the presence of alkali metal carbonate, characterized in that the reaction is carried out in the presence of a phase transfer catalyst. 2. The method according to claim I, characterized in that one in Presence of alkali metal fluoride works. 3. The method according to claim 2, characterized in that one in Presence of 0.1 to 1 mole of alkali metal fluoride per mole Dihalogen compound of formula II works. 4. The method according to claim 1, characterized in that first an aromatic dihalogen compound of the general formula II in which Hal stands for chlorine, in the absence of an aromatic Dihydroxy compound of the general formula I with the equivalent Amount of an alkali metal fluoride in the presence of a Phase transfer catalyst heated at least 5 hours and then to the Reaction mixture the aromatic dihydroxy compound of the general Formula I and the alkali metal carbonate are added. 5. The method according to claim 1, characterized in that the phase transfer catalyst is a pyridinium salt of the general formula IV in which
Z is hydrogen, R ³ , R ³ R ⁴ N or R ⁵ R ⁶ N
R ³ and R ^{4 are} independently C ₁ -C ₆ alkyl or
R ³ and R ⁴ together form an alkylene group with 4 to 10 C atoms, which forms a saturated 5 or 6 ring with N atom,
R ⁵ and R ^{6 are} phenyl rings which can be substituted independently of one another by C ₁ -C ₄ alkyl, halogen or nitro groups,
RC ₁ -C ₅ alkyl or a phenyl ring which can be substituted by C ₁ -C ₄ alkyl, halogen or nitro groups,
X and Y independently of one another hydrogen, C ₁ -C ₄ alkyl or R ⁷ R ⁸ N
R ⁷ and R ^{8 are} phenyl rings which can be substituted independently of one another by C ₁ -C ₄ alkyl, halogen or nitro groups, and
A is an anion. 6. The method according to claim 5, characterized in that as Phase transfer catalyst a pyridinium salt of the general formula IV where X and Y are hydrogen and R is the neopentyl radical mean. 7. The method according to claim 5 or 6, characterized in that as Phase transfer catalyst a pyridinium salt of the general formula IV used, in which Z represents a dialkylamino radical. 8. The method according to claim 5 or 6, characterized in that uses a compound, the Z is the 4'-methylpiperidinyl radical.