DE1420485B1 - Process for the preparation of polyphenylene oxides - Google Patents

Description

Processes for the oxidation of phenols in the presence of amines and copper (II) salts are known. Brackmann et al report in Rec. Trav. Chem. 74, 937/955, pp. 1021 to 1039, 1071 to 1080, 1101 to 1119 (1955), about an experimental work, in which oxygen with monocyclic and bicyclic phenols is reacted in the presence of a copper (II) salt and primary, secondary and tertiary amines. In Both the monocyclic and the bicyclic are present in the presence of primary and secondary amines Phenols oxidize with the formation of chemical compounds in which the amines are a constituent of the formed molecule. In the presence of a tertiary amine, only the bicyclic Phenols, e.g. B. naphthols, oxidize. In this case the products form simple connections, such as Naphthoquinones made from 1 or 2 molecules of naphthol, naphthones made from 2 molecules Naphthol were formed, as well as in the case of / ^ - naphthol (naphthol-2), one of 3 molecules naphthoquinone formed by naphthol. Against it

OH

no reaction occurs when attempting to use monocyclic phenols in the presence of a cupric salt and tertiary amines to oxidize. Brackmann states on p. 939: "With regard to the phenols of the benzene series, tertiary amines are completely inactive".

It has now been found that it is still possible to oxidatively link monocyclic phenols, where with almost quantitative yield higher molecular weight polyphenylene ethers with particularly favorable properties can be obtained. The amine is not part of the reaction product, as is the case with the oxidation processes of Brackmann et al.

The invention relates to a process for the preparation of polyphenylene oxides, which is characterized in that a copper amine complex prepared from a tertiary amine and a copper (I) salt soluble therein is mixed in the presence of oxygen at temperatures not exceeding 100 ^° C. with phenols general formulas

OH

or

II

in which X is a hydrogen, chlorine, bromine or iodine atom, R 'is a halogen atom or R and R are Hydrogen atom, a hydrocarbon, hydrocarbonoxy, halohydrocarbon or a Halohydrocarbonoxy radical, where the aliphatic halogenated substituents at least Have 2 carbon atoms between the halogen atom and the phenol nucleus, all aliphatic substituents at least one hydrogen atom on the carbon atom bonded to the phenol nucleus carry and R and R 'in the general formula II not both a halogen atom or an aryl, hydrocarbonoxy or halocarbon oxy radicals.

Here, the halocarbon oxy radicals should have at least 2 carbon atoms between one Have halogen atom and the phenol nucleus. Halomethyl groups are hydrolytically so reactive that that they form undesirable by-products in the oxidation reaction. They are quite general Except for substituents R or R 'which carry an aliphatic tertiary a-carbon atom. the The reasons for this are set out below.

The hydrogen atom participates in the oxidation reaction in the presence of the copper catalyst system the phenolic group of a phenol molecule, a hydrogen, chlorine, bromine or iodine substituent in the ortho (2) or para (4) position of another phenol molecule and oxygen below the formation of water according to the following reaction scheme, which shows the para position applies:

3 2

In the following, the numbers are used to designate the position of the substituents and the connecting points: η is an integer of at least 10 and is 100 to 1500 and more in the film and fiber-forming range.

The type of copper (I) salt used does not matter if it only exists in the copper (II) state and can form a complex with the tertiary amine which is soluble in the reaction medium. The necessity of being able to exist in the copper (II) state is based on the assumption that the oxidation of the phenol is brought about by an intermediate product of an activated copper (II) amine complex, which reacts with the phenol to regenerate the copper (I) -amine complex reacts. As far as + H ₂ O

can be determined, it is impossible to start this activated complex from a copper (II) salt to build. Typical examples of the copper (I) salts suitable for this process are: copper chloride, Copper (I) bromide, copper (I) sulfate, copper (I) azide, copper (I) tetramine sulfate, copper (I) acetate, copper (I) propionate, Copper (I) palmitate, copper (I) benzoate, etc.

Copper (I) chloride, copper (I) bromide and copper (I) azide provide the polyphenylene ethers with the highest levels Molecular weight. Although no copper (II) sulfite is known, copper (I) sulfite can be used because it is apparently oxidized to copper (I) sulfate. Copper (I) salts, such as copper (I) iodide, copper (I) sulfide, copper (I) cyanide and copper (I) rhodanide are for use

not suitable in this process because they are either insoluble in tertiary amines or they are not can form stable copper (II) salts. For example, copper (II) cyanide and copper (II) rhodanide decompose autogenous to the corresponding copper (I) salts. The existence of copper (I) nitrate and copper (I) fluoride is not known, but the amine complexes can be prepared in situ. A substitute for the copper (I) salts through copper (II) chloride, copper (II) sulfate, copper (II) chlorate and copper (II) nitrate does not provide oxy- ίο dation of monocyclic phenols in the presence of a tertiary amine. Confirm these results the work of B r a c k m a η η et al.

Examples of tertiary amines that can be used in the practice of the invention are aliphatic tertiary amines, such as trimethylamine, triethylamine, tripropylamine, tributylamine, diethylmethylamine, dimethylpropylamine, Allyl diethylamine, dimethyl-n-butylamine, diethylisopropylamine, benzyldimethylamine, Dioctylbenzylamine, dioctylchlorobenzylamine, dimethylcyclohexylamine, dimethylphenethylamine, benzylmethylethylamine, Di- (chlorophenethyl) -brombene-

• zylamine, 1-dimethylamino-2-phenylpropane and 1-dimethylamino-4-pentane.

If aliphatic tertiary amines are used, at least two of the aliphatic groups should be used be straight chain hydrocarbon groups.

Examples of cyclic amines are the pyridines, such as pyridine itself, quinuclidine, the N-alkylpyrroles, the N-alkylpyrrolidines, the N-alkylpiperidines, the Quinolines, isoquinolines, N-alkyltetrahydroquinolines, N-alkyl tetrahydroisoquinolines and N-alkyl morpholines including the ring-substituted products of these cyclic amines in which one or more Hydrogen atoms on the ring-forming carbon atoms can be substituted by the following groups: Alkyl (ζ. B. methyl, ethyl, propyl, butyl, amyl, hexyl, heptyl, octyl and their isomers and Homologues), alkoxyl (e.g. methoxyl, ethoxyl, propoxyl, butoxyl and the isomers and homologues), Aryl (ζ. B. phenyl, tolyl, dimethylphenyl, chlorophenyl, Bromotolyl, naphthyl, chlorobromonaphthyl and their isomers and homologues), oxyaryl (e.g.

»Oxyphenyl, oxytolyl, oxyxylyl, oxychlorphenyl, oxynaphthyl groups and their isomers and homologues). The ring substituents can be identical or different hydrocarbon groups. Piperidines, Pyrroles, pyrrolidines, tetrahydroquinolines or tetrahydroisoquinolines are tertiary in the form Amines used in which a hydrocarbon radical, as defined above, with the amine nitrogen connected is.

The effect of an N-aryl group in tertiary amines, e.g. B. Ν, Ν-dimethylaniline or methyldiphenylamine is to reduce the basicity of the amine so that its ability to form the Copper complex is largely reduced. In addition, the stability of the amine is also reduced largely under oxidizing conditions. Because of these two effects, it is better not to use one tertiary amines bearing an N-aryl substituent.

The preferred inclusion of the ortho or para positions in the oxidation reaction is so pronounced that if one of the three positions is substituted with a halogen (except fluorine, which is not reacts) and the other two are substituted with a hydrocarbon radical that removes halogen will. In this case the halogen atom reacts with 1 molecule of the copper catalyst and is inactivated him. Therefore, it is necessary to use 1 mole of catalyst per atom of removed halogen. This halogen removal does not extend to phenols, which are a halogen in either of the two ortho positions because in this case the electronegativity of the two halogens is the phenolic hydroxyl group inactivated so that the phenol cannot be oxidized by this process. If a hydrocarbon and a halogen occupy the ortho positions and either hydrogen or a halogen except Fluorine, the para position, only the para position seems to take part in the oxidation reaction. Take hydrogen and a hydrocarbon radical in the ortho positions and a halogen, except Fluorine, the para position, then both hydrogen and halogen can take part in the oxidation reaction in the same way as when both positions would be substituted with hydrogen. As a reaction involving the hydrogen atoms in the ortho or para positions does not destroy the catalyst, only a small one has to be catalytic amount applied, on the order of 0.1 to 10 mole percent based on the moles to be oxidized phenol. Therefore, phenols are preferred according to the invention, which at the in the Oxidation reaction involved ring position carry hydrogen.

Halomethyl groups are hydrolytically so reactive that they are undesirable in the oxidation reaction Form by-products. Hence, phenols containing such substituents become major reactants best excluded from the reaction mixture, although in small amounts may be present as modifiers. Other ring substituents, such as nitro, cyano, carboxyl and formyl groups which can react with amines or copper salts should also be used as substituents the phenols used as main reactants are excluded, although phenols, containing these groups, in small amounts as modifiers of the polymer obtained can be used.

It was also found that groups with large space requirements, i.e. H. approximately spherical groups, z. B. the tert-butyl group and higher homologues, aryl groups, oxyalkyl groups, the oxidation reaction not stopping, but only forming diphenylquinones.

This leads to the following observation regarding aliphatic Orthosubstituents on the phenolic starting materials: Substituents that form an aliphatic Carrying tertiary a-carbon atoms, deliver the corresponding diphenylquinones and prevent the formation of Polyphenylene ethers if at least one such ortho-substituent is present. Typical examples for such substituents are:

-QCH ₃ J,

—C

-C (C ₂ H ₅ J ₂ C ₄ H ₉

Substituents that have an aliphatic secondary ίο Have α-C atoms prevent the formation of polyphenylene ethers not, but such an ortho-substituent causes at least a minor one Formation of the corresponding diphenylquinone. Have two such ortho substituents As a result, the main part of the product consists of the corresponding diphenylquinone and only one smaller proportion of the polyphenylene ether is. Orthosubstituents that have an aliphatic primary a-C atom do not prevent the formation of polyphenylene ethers.

It was also found that to obtain polyphenylene ethers with a very high molecular weight only the para position and the phenolic hydrogen take part in the oxidation reaction to be allowed to. In contrast, polyphenylene ethers with low and medium molecular weights can pass through Oxidation of phenols obtained with only one reactive ortho division. Will oxidation performed with phenols, those with both ortho and para positions as well as with the phenolic Group can react, the polyphenylene ethers obtained represent a mixture of polyphenylene ethers with a three-dimensional structure. Such substances are extremely reactive and tend to transform liquids into gels without forming soluble solids that are isolated can. Such substances are available as potting resins, impregnating agents or as thermosetting adhesives useful.

Surprisingly, it is possible by the inventive process to produce polyphenylene ether with a very high molecular weight, extremely high softening points in the range of 250 to 300 ⁰ C or more, as is apparent from the required deformation to its pressing temperatures. Depending on the manufacturing conditions, they ^{either remain thermoplastic with continued heating in vacuo to 250 °} C. or they harden to an infusible state in which they are no longer in the usual organic solvents such as toluene, xylene, chloroform, nitrobenzene, etc. which they were soluble before the heat treatment, are soluble. Low molecular weight materials can be obtained either by controlling the amount of reacting oxygen or by adding to the reaction mixture a liquid which forms a solvent for the starting material but is not a solvent for the reaction products after they have reached a predetermined molecular weight. The rate of oxidation depends on the amount of copper (I) catalyst present. In order to achieve a sufficient reaction rate, it is preferred to use at least 1 mol percent copper (I) catalyst, based on the amount of phenol used. There should be 2 amine nitrogen atoms per copper atom. Polyphenylene ethers with molecular weights of at least 10,000 can be obtained by the process according to the invention.

These high molecular weight substances represent new chemical masses. So far, polyphenylene ethers were z. B. produced by the Ullman reaction between a parabromophenol and a potassium phenolate in the presence of copper powder. However, such a reaction is apparently unable to produce polyphenylene ethers having more than about eight repeating units, so that the molecular weights are limited to about 1,000. Such substances are still crystalline and have sharp melting points. If you brominate z. B. Diphenyloxyd and reacts it with potassium phenolate, brominates the compound obtained again and reacts it again with potassium phenolate, so the extreme product to be obtained seems to be C ₆ H ₅ O (C ₆ H ₄ O) ₆ C ₆ H ₅ , which has a melting point of 199 to 200 ° C.

The preferred class of phenols for making high molecular weight resins is equivalent to formula

OH

in which R and R "correspond to the definition of formula 2 and the three positions without substituents are shown to carry a hydrogen atom attached to the ring carbon.

Typical examples of monovalent hydrocarbon radicals, which in all of the above formulas R and R " are: alkyl, including cycloalkyl, ζ. B. methyl, ethyl, propyl, isopropyl, butyl, sec. Butyl, tert. Butyl, isobutyl, cyclobutyl, amyl, cyclopentyl, hexyl, cyclohexyl, methylcyclohexyl, Ethylcyclohexyl, octyl, decyl, octadecyl; Alkenyl, including cycloalkenyl, ζ. B. vinyl, allyl. Butenyl, Cyclobutenyl, isopentenyl, cyclopentenyl, linolyl; Alkynyl e.g. B. propargyl; Aryl, including alkylaryl, z. B. phenyl, tolyl, ethylphenyl, xylyl, naphthyl, methylnaphthyl; Arylalkyl, e.g. B. benzyl, phenylethyl, Phenylpropyl, tolylethyl. The monovalent halocarbon radicals can be the same as that hydrocarbon radicals indicated above, except methyl, in which one or more hydrogen atoms are replaced by halogen. Examples are: chloroethyl, bromoethyl, fluoroethyl, dichloroethyl, Bromopropyl, difluoroiodoethyl, bromobutyl, fluoramyl, chlorovinyl, bromallyl, fluoropropyl, mono-, di-, Tri-, tetra- and pentachlorophenyl, mono-, di-, tri- and tetrabromotolyl, chloroethylphenyl, ethylchlorophenyl, Fluoroxylyl, chloronaphthyl, bromobenzyl, iodophenylethyl, phenylchloroethyl and bromotolylethyl.

Typical examples of monovalent hydrocarbonoxy radicals are: methyloxy, ethoxy, propyloxy, Isopropyloxy, butyloxy, sec-butyloxy, tert. Butyloxy, amyloxy, hexyloxy, octyloxy, decyloxy, vinyloxy, Allyloxy and butenyloxy. The monovalent halohydrocarbonoxy groups can be the same as the above oxyhydrocarbons with the exception of the methyloxy radical, in which one or more hydrogens by halogen, e.g. B. fluorine, chlorine, bromine or iodine are replaced.

As already mentioned, phenols with two reactive positions provide three-dimensional ones

Polymers that are and tend to be extremely reactive. Polymers of complex structure too form, surprisingly it was found that phenols containing two or three unsubstituted ortho- or have parallels, d. H. two or three reactive positions, forming more solid fusible polyphenylene ethers similar to those obtained from phenols, the have only one reactive ortho or para position. This is done through the Using a tertiary amine in the catalyst system achieved the one or two large bulky Bears substituents or spatially immobile groups that effectively have one or both ortho positions To block.

The amine copper complex apparently attaches itself to the phenolic hydroxyl group when it is used as Oxidation catalyst works. Therefore, when the amine carries large bulky organic groups that Shielding or sterically hindering ortho positions, this has the effect that the reaction with the para position, if it is reactive, expires. If the para position is not reactive, then the reaction takes place still beyond one of the ortho positions, but the products have a much lower molecular weight, than was the case with phenols, which have only one reactive ortho division. It was found that the cyclic amines are particularly well suited for use in this catalyst system are when one or both ortho positions of the phenol are to be blocked. With the cyclic Amines, such as the pyridines and quinolines, the rings are spatially arranged so that each substituent blocks an unsubstituted ortho position of the phenol either in the 2- or 6-position, while Substituents in both the 2- and 6-positions, both unsubstituted ortho positions of a phenol To block. Therefore, if a phenol only has one unsubstituted ortho position, the cyclic amine is required only one substituent in the 2-position, e.g. B. α-Picoline- (2-methylpyridine). If both ortho positions of the phenol are unsubstituted, the cyclic amine would be Require substituents in both the 2- and 6-positions, e.g. B. 2,6-lutidine.

In general, amines, including tertiary amines, tend to break up in the presence of oxygen discolor, even if left in the presence of a limited amount of air. This tendency to Discoloration with simultaneous formation of complex products appears with pyridine and its ring-substituted derivatives not to be as pronounced as e.g. B. in the closely related quinolines. It was found that when using tertiary amines, which tend to discolour, in the absence a nitroaromatic compound, the products of the invention are not as pure and the physical ones Properties are not as favorable as when a tertiary amine is used, which in Presence of oxygen is stable. Therefore, under such conditions, the use of Pyridine is preferred as the tertiary amine in the catalyst mixture.

It is assumed that 1 mole of cuprous salt forms a complex with 2 moles of amine. This complex can react with oxygen to form an oxidized intermediate that reacts to various Way can form a complex with the phenol. The latter complex activates the aryl core so that the polymer chains are formed while the catalyst is restored to its original state will. This assumption is based on the fact that when oxygen is introduced into the Catalyst system up to saturation with subsequent addition of phenol without further addition of oxygen 1 mole of phenol is oxidized per 2 moles of catalyst present. The following equations show these reactions, where an 0 represents the aryl nucleus of the phenolic reactant, (A) the is tertiary amine and CuCl stands for a typical copper (I) salt.

2 (A) + CuCl H ₂ O: Cu: Cl ° ²

(A) HO: Cu: Cl + H ₂ O

(A)

(A) ^ ° M> ₀ O: Cu: Cl

(A)

Herein, b can be two or more. The above equations also show the contribution of the water.

Although mixtures of tertiary amines and mixtures of copper (I) salts can be used, there is no benefit therefrom. Preferably, the copper (I) salt is dissolved in the tertiary amine prior to the addition of the phenolic reactant. In some cases, the dissolution of the copper salt can be accelerated by heating the mixture, bubbling in air or oxygen, or a combination of both. To fully utilize the copper, enough amine should be added to dissolve all of the added copper salt through complex formation. Bigger (A)
'■ £ L (0O) _b + H ₂ O: CuCl

(A)

Excesses of amine do not favorably influence the reaction, but they can in some cases be desirable to completely dissolve all phenolic reactants and as a solvent for the To serve reaction products. Other solvents such as alcohols, ketones, hydrocarbons, chlorinated hydrocarbons, Nitro hydrocarbons, ethers, esters, amides, mixed ether-esters or sulfoxides can be present in the reaction system as long as they do not interfere with the oxidation reaction or because of it take part. Then oxygen or an oxygen-containing gas is introduced into the reaction mixture and causes an exothermic reaction to occur there with the formation of water as a by-product.

009 542/373

To prepare the polyphenylene oxides by the process according to the invention one prevents z. B. in the case of batch operation, it is best for this water of reaction to escape from the reaction vessel, or the escape of the water is controlled in a manner known to the person skilled in the art so that there is always 1 mole of water per mole of copper catalyst. When carrying out the invention, the oxygen can be diluted with an inert gas such as nitrogen, helium or argon, or air is used Temperature, which is indicated by the release of heat during the reaction. Typically, the oxidation reaction is controlled by removal of heat so that the maximum temperature does not exceed 100 ⁰ C and preferably not higher than 8O ⁰ C.

Usually the introduction of oxygen into the reaction mixture is continued until no heat more is released or the intended amount of oxygen is absorbed. But you can also during the oxidation reaction continuously or intermittently the same or a different phenol as the starting material add to produce a mixed polyphenylene ether having a different structure, as if one had used the mixed phenols as starting material. To stop the reaction, if the catalyst system is destroyed by adding an acid, preferably a mineral acid, such as hydrochloric acid or sulfuric acid, which reacts with the tertiary amine and with the copper (I) salt. Or the reaction product is separated from the catalyst, either by filtering off, if it has precipitated is, or by pouring the reaction mixture into a material suitable for the catalyst system Is solvent, but is not a solvent for the reaction product. For a change you can also precipitate the copper as an insoluble compound and before isolating the reaction product from filter off the solution, or a gelling agent is added which inactivates the copper. After this if the reaction product has precipitated, it can be overturned any number of times for purification. Last will it is filtered and washed free of any remaining impurities. After drying the resin can be processed by compression molding, extrusion molding, or melt spinning, or one can Dissolve it in solvents to produce solutions that are useful in the production of coatings, Find fibers or adhesives use.

Modifiers for the reaction can be added to the reaction mixture in order to produce products with to obtain improved properties over those made without modifying agents.

Particularly suitable modifiers are: anion exchange resins, especially those that contain tertiary amine groups as an active ingredient, nitroaromatics, such as mono-, di- and trinitrobenzenes, mono-, di- and trinitrophenols; Peroxide deactivators, like heavy metals and their oxides; Adsorbents such as activated charcoal, Kresel gel or clay.

Although the anion exchange resins are insoluble in the reaction mixture, they are apparently somehow effective with the copper amine complex, likely as promoters or cocatalysts. The use of an anion exchange resin as a modifier is particularly useful when that is the case oxidizing phenol either in one or both ortho positions to the phenolic hydroxyl group is unsubstituted. As stated above, this reaction would usually be more specific using run tertiary amines. But it was found that anion exchange resins, which are insoluble Carrier-bound dialkylamino groups contain, in some respects, a beneficial effect on exercise the course of the reaction similar to those obtained with the specific amines. If z. B. Orthocresol in pyridine solution with a copper (I) chloride catalyst in the presence of an anion exchange resin is oxidized, which contains dimethylamino groups on a styrene divinylbenzene carrier, so will a soluble polymer is formed. If the same reaction is carried out in the absence of the anion exchange resin or the special amine catalysts, complex products are formed that are not so are useful. As far as is known, these resins do not have to meet any requirement other than that they contain anions can absorb, which is a characteristic of all anion exchange resins. Typical examples of such Anion exchange resins that can be used are amine modified or quaternized Polymers, e.g. B. crosslinked styrene divinylbenzene polymers, styrene glycol dimethylacrylate polymers, aniline formaldehyde resins, Aryl polyamine formaldehyde resins, phenol formaldehyde resins, urea formaldehyde resins, and Melamine-formaldehyde resins modified with amines. Those compounds that are reaction products from formaldehyde can be modified with amines as long as they are in the methylol state are. All compounds can be chloromethylated and then reacted with amines. Such Fabrics are quickly available and commercially available. Because primary and secondary amine groups with oxygen react, the amine group should be tertiary or quaternized, so that the effectiveness of the resin during the oxidation reaction is not impaired.

The effect of adding nitroaromatics, such as picric acid and nitrobenzenes, to the reaction mixture appears to lie in the destruction of by-products or the prevention of their formation. These would react with the main product to form impure material with less desirable ones Properties. The use of nitroaromatics is particularly advantageous in the manufacture of resins with a much lighter color than this is possible under the same reaction conditions without them is. Their use is particularly desirable when using tertiary amines as a catalyst, which are not resistant to oxidation, d. H. discolor easily in the presence of oxygen, e.g. B. aliphatic tertiary amines. Since the nitrophenols can form complexes with the copper amine catalyst, Sufficient catalyst should be used to allow an excess over that of the nitrophenol present responsive is guaranteed.

To prevent the accumulation of peroxides that attack the phenol at an undesirable Position of the aromatic ring, one can use peroxide deactivators, z. B. selenium, silicon, lead, mercury, copper, silver, gold, nickel, palladium, platinum, cobalt, rhodium,

Iridium, iron, ruthenium, osmium, manganese, chromium, molybdenum, tungsten, vanadium, niobium, cerium, thorium, as well as their oxides or salts. Other peroxide deactivators are on pages 467 to 501 of »Hydrogen Peroxides ”by Schumb, Satterfield & Wentworth, Rheinhold Pub. Corp., New York, N.Y., 1955, described.

The reaction can also be carried out in the presence of adsorbents, which tend to produce by-products to remove which are present in a small amount and adversely affect the reaction can. Examples of these adsorbents are: activated carbon, silica gel (including xerogels, aerogels, Silica, etc.), clay and magnesium silicate.

It has also been found that the quality of the polyphenylene ethers can be improved if a organic, sulfur-containing compound is added, which leads to a solution of the product at the end of the oxy-

The following examples illustrate the oxidation of 2,6-disubstituted phenols.

example 1

In a reaction mixture containing 5 g of 2,6-methylphenol

Containing 1 g of Cu ₂ Cl ₂ and 100 ml of pyridine, oxygen was passed in for 10 minutes. During the reaction time, the temperature rose to a maximum of 70 ^° C. No water was removed during this process. The product was obtained by pouring the reaction

dation reaction also has reducing properties when mixed in about 500 ml of dilute hydrochloric acid. Typical compounds of this type are thio-precipitated and separated off by filtration.

The product, poly (2,6-dimethyl-1,4-phenyl) -ether, is characterized by repeating structural units the formula

urea and its derivatives. Remove these substances
not just all of the copper in the product, but them
also destroy any color-forming by-products that
may be undesirable in the end product. This 25
Color formers appear to be diphenylquinones. These
colored fabrics are chemical by-products and
no parts of the polymeric molecule as you can make them out
the polymer can remove. However, if a
colored end product is desired, so one must 3 °
intentionally added hydroquinones to the reaction mixture
or add quinones to achieve a controlled, desired color in the end product, as part of
of the polymer molecule cannot be removed. It was in virtually quantitative yield

Typical hydroquinones which can be used for this purpose are: 35 obtained.

Hydroquinones, catechol, substituted hydroquinones, The molecular weight of the product was after

Light scattering method is in the range from 300,000 to 700,000, and it did not melt at 300 ⁰ C. The powder obtained by precipitation could be compression molding, calendering or extrusion into a unitary piece at pressures of 140 kg / cm ² at 240 ⁰ C. From 10% solutions of the polymer in each of the following solvents, 1. benzene, 2. toluene, 3.XyIoI, 4. tetrahydrofuran, 5. pyridine, could be painted on

Vigorously stirred solution containing the phenol and a 45 on a glass surface and peeling off after the ver-cupric salt contains, is initiated so quickly that vapors of the solvent produce tough films.

These films were oriented by stretching and cold drawing. By extruding a saturated solution of the polymer in xylene in air, fibers were additional suitable solvents. The oxygen produced 5 °. This could also be done by stretching is introduced into the reaction mixture for so long, and cold drawing orientates, until no more heat is developed. The tem-. .

temperature rises first and then begins to fall, e 1 s ρ 1 e I

until the reaction is complete. If air is used instead of oxygen, then the reaction

product either soluble in the reaction mixture, the reaction proceeds more slowly, and the resulting or partially soluble, the latter will be lower at about the maximum temperature as the heat passes through 5 times the volume of a nonsolvent for which the inert nitrogen is removed. If z. B. Polymers added. So much for the non-solvent air in a well-stirred mixture of 5 g of 2,6-dimeter dilute hydrochloric acid is present, use methylphenol, 1 g of copper (I) chloride and 125 ml of pyman if enough acid is passed in to feed everything in the reaction mixture, the temperature within the mixture rises to neutralize any amine present. When half past fourteen minutes from 30 to 43 ° C and then falls aqueous hydrochloric acid represents the nonsolvent, so over the next 9 minutes to 36 ° C. After it is about 6normal, although more dilute or by this time the reaction mixture has been in Concentrated solutions can also be used- methanol is poured and then thoroughly mixed with menene. The precipitated reaction product is then washed off, which is a sufficient amount filtered. As far as the original reaction product contains 12 molar hydrochloric acid, the methanol becomes acidic borrowed reaction mixture is insoluble, it will hold out. The yield was 4.9 g versus 4.92 g Filter removed. according to the theory, poly (2,6-dimethylphenyl-1,4) ether,

such as toluhydroquinones (methylhydroquinone), halogen-substituted hydroquinones, such as tetrachlorohydroquinone, the naphthohydroquinones, the dihydroxyanthracenes or the dihydroxyphenanthrenes.

The following basic procedure is used in the examples below:

In general, the oxidations are carried out at room temperature by adding oxygen to a

not everything can be absorbed. The latter are dissolved in a suitable solvent, which is common the amine or the amine with an additional

which has the same repeating unit as above. It had a true viscosity of 0.625.

Example 3

The true viscosity and physical properties can be varied by regulating the amount of oxygen absorbed in the reaction mixture. In order to measure the amount of oxygen actually absorbed, it was necessary to have a closed Use a system that has a suitable storage vessel for the oxygen and a suitable leveling device, to keep the whole system at atmospheric pressure. Two gas burettes through one Series of stopcocks were connected to a leveling ball, a source of oxygen, a pressure gauge and the reaction vessel provided a suitable closed system in which a gas burette was included Oxygen could be recharged while the oxygen from the other burette was approaching was fed. Using this system, two 50 g lots of 2,6-dimethylphenol were made oxidized in the presence of 1 g of copper (I) chloride and 500 ml of pyridine. The phenol was not added, before the other substances were saturated with oxygen. The reaction temperature rose to 30 ° C held by the reaction vessel was partially immersed in a constant temperature bath. To In 60 minutes, 102% of the theoretical amount of oxygen needed to oxidize all phenols had been absorbed to polyaryl ether is required. At this point the reaction mixture was poured into water, to fail the product. It was washed out with dilute aqueous hydrochloric acid for so long until no more odor of pyridine could be detected, then it was washed with water. The polymer was digested six times in acetone, followed by dissolving in chloroform and precipitating in methanol. Both lots were combined by dissolving in chloroform, mixed, and soaked in methanol failed. This product is listed as Product A in Table I. Product B was in the same Made like product A, but the reaction was carried out in the case of the 1st batch containing only 40 g of phenol was continued for 70 minutes and in the case of the 2nd batch, which contained 50 g of phenol, for 90 minutes. In both cases 107% of the theoretical amount of oxygen was required for the oxidation of the phenols is absorbed. Products is a polymer that is manufactured using a two-step process became. The procedure was the same as for product A, only 2.5 g of cuprous chloride was used. After 3.5 minutes, about 50% of the theoretical amount of oxygen had been absorbed. The reaction was terminated by adding so much hydrochloric acid that the solution became acidic. That Polymers were extracted from the aqueous solution with benzene and washed with 5% aqueous sodium hydroxide solution, to remove any unreacted phenol. The benzene solution was washed with water and dried with a desiccant. The benzene was withdrawn and a brittle polymer of low molecular weight isolated. 29 g of this low molecular weight polymer were dissolved in 620 ml of pyridine containing 3.1 g of copper (I) chloride and followed for 1 hour by the same procedure as oxidized in the first step. Products were made from the reaction mass by the same procedure like product A isolated.

The physical and electrical properties of these three polymers are compared in Table I.

Table I.
Physical properties of poly (2,6-dimethylphenylene-1,4) ether

A. B. C. True viscosity 0.50
20,000
230 to 250
1.07
1 099 0.97
45,000
250 to 270
1.07
1225 1.45
70,000
270 to 290
1.06
1064 Approximate molecular weight
(after osmotic pressure)
Optimal pressing temperature, ° C
Density (pressed film) ... 469 875 1 113 Ultimate tensile strength (kg / cm ² ) at
25 ° C 203 770 1 064 150 ^c C 72 357
81 686
64 175 ° C 71
53 133
167 170
230 200 ° C 2.6
0.0006
1 · 10 ¹⁸ 140
2.60
0.0007
6 · 10 ¹⁷ 200
2.60
0, '0008
1 · 10 ¹⁸ Elongation,%, at
25 ° C 150 ° C 175 ° C 200 ° C Electrical Properties
Dielectric constant 25 ° C
(60 Hz) tang δ (60 Hz) Specific DC resistance
(Ohm cm)

continuation

Specific AC resistance (ohm cm)

Dielectric constant 175 ° C (60 Hz)

tang δ (60 Hz)

Specific DC resistance (ohm cm)

Specific AC resistance (ohm cm)

1 · 10 ¹³

2.60 0.0034

9-1O ¹³ 5 · 10 ¹²

If these three polymers are ^{exposed to saturated steam at 150 °} C. (4.7 atm pressure) for 3 weeks, the true viscosity is the same as before the test, from which it can be seen that the polymers are not subject to hydrolysis. This resistance is also found when the polymers are heated to 175 ° C for 3 weeks in a nitrogen atmosphere. Heating to this temperature in oxygen causes crosslinking of the polymer and some oxidation of the alkyl side chains.

Example 4

Other tertiary amines can be used both as part of the catalyst and as solvents for the reaction be used. The procedure of Example 1 was repeated, only quinolines, N-methylmorpholine, a-picoline, 2,6-lutidine, tri-n-propylamine, Triethylamine and N, N-dimethylbenzylamine are used in place of pyridine. In each case changed the molecular weight and color of the end product with the amine used. The brightest colored Products were made with the monoarylcyclic amines, e.g. B. pyridine, α-picoline and 2,6-lutidine. Aliphatic amines are poor solvents for the reaction, and so they are in theirs Use obtained products lower than with other amines.

Example5

45

The reaction product can be derived from the reaction mixture from Example 1 except for that used there also precipitate dilute hydrochloric acid with other means. The procedure of Example 1 was repeated, only methanol, ethanol, isopropanol and acetone were used as precipitants instead of the diluted hydrochloric acid is used. In either case, the product failed just as quickly and exactly like that easily filtered off like the product from Example 1. The special precipitating agent had no noticeable influence on the physical or chemical properties of the product. Although it is not necessary it is usually desirable to add enough abnormal aqueous hydrochloric acid to precipitate to neutralize the amine and inactivate the cuprous salt. This step supports education of a purer product.

2 · 10 ¹³

2.55
0.002

2 · 10 ¹³
4 · 10 ¹²

1 · 10 ¹³

2.60
0.002

9 · 10 ¹⁴
5 · 10 ¹²

Example 6

Pyridine can be combined with other solvents to make a polymer. In the Results shown in Table II show that the molecular weight of the polymer formed depends on the depends on the specific solvent system used. Propanol is a solvent for the starting materials but not for the reaction products. The molecular weight is the softening point and directly proportional to the true viscosity of the polymer.

Oxygen was passed in for about 10 minutes into reaction mixtures which contained 10 parts of 2,6-dimethylphenol, 1 part of Cu ₂ Cl ₂ and the stated amounts of pyridine and n-propanol. During the duration of the reaction, the temperature of the solutions rose from 30 ^° C. to maximum values in the range from 60 to 70 ^° C. During the reaction, in which some precipitate was formed, no water was removed. The reaction products were completely precipitated by pouring into ethanol containing hydrochloric acid and separated off by filtration. The products had the same repeating unit as in Example 1, but the molecular weight decreased with increasing amounts of propanol, as the results of Table II show.

The true viscosity is determined by dissolving the polyaryl ether in a suitable solvent and measuring the relative viscosities over a certain one Concentration range determined. If a suitable solvent has been used, it gives a straight line plotting the viscosity-concentration values. By extrapolating this line the value of the true viscosity is obtained from the concentration.

Table II

Parts by weight
solvent used n-propanol Softening
Point Real
viscosity Pyridine 93.8 of the product 6.2 87.8 219 ° C 0.21 12.2 54.5 235 ⁰ C 0.23 45.5 melts 0.64 at 300 ° C not

Example 7

Molecular weight is not only influenced by the ratio of solvent to pyridine, but also the specific solvent catalyst concentration and the reaction time. Table III shows the Results obtained with different solvents as well as with different amines. In in all cases the oxidized phenol was 2,6-dimethylphenol.

009 542/373

Table III

phenol CuCl 1 Amine Pyridine solvent toluene Temperature ⁰ C
Start-max. 70 reaction time Real
viscosity (G) (G) (ml) (300) (ml) (Minutes) 50 2 1 Pyridine o-dichlorobenzene 50 73 about 10 0.90 (50) (50) 10 1 1 Pyridine / 3-methoxyethanol 30th 75 5 0.87 (50) (50) 10 1 1 Pyridine t-amyl alcohol 30th 72 4th 0.67 (50) (50) 10 1 Pyridine ß-acetoxyethanol 30th 74 5 0.97 (50) (50) 10 1 Pyridine Benzonitrile 30th 80 12th 0.43 (50) (50) 10 1 Pyridine Dimethylformamide 30th 44 4th 0.48 (20) (120) 10 1 Triethylamine ß-phenoxyethanol 30th 50 4.5 0.49 (100) (100) 5 1 Dimethylstearylamine Dichlorobenzene # 39 27 0.35 (0.1) (100) 5 0.1 Dimethylstearylamine Dichlorobenzene 24 37 41 0.12 (1.0) (100) + 10 ml 5 0.1 Dimethyl sulfoxide 26th 240 0.78 Dimethylstearylamine o-dichlorobenzene 40 (D (100) 5 0.1 t-amyl alcohol 26th 104 0.44 (10) Dimethylstearylamine Tetrachlorethylene 38 (1) (100) 5 0.1 t-amyl alcohol 25th 142 0.36 Dimethylstearylamine Xylene 50 (D (100) 5 0.1 t-amyl alcohol 25th 158 0.47 (10) Pyridine t-amyl alcohol 62 (50) (80) 10 1 Pyridine t-amyl alcohol 26th 61 7th 0.75 (30) (50) 10 1 Dimethyl sulfoxide 26th 7th 0.52 (50) Dimethylbenzylamine Nitrobenzene 50 (30) (100) 5 Tributylamine Nitrobenzene 31 48 32 0.59 (30) (100) 5 Pyridine t-amyl alcohol 32 66 31 0.36 (50) (80) 10 Pyridine CH ₂ Cl ₂ 27 51 8th 0.69 (75) (50) 5 31 27 0.88

Example 8

This example shows that polymers of different molecular weights differ based on solubility of the special polymer in the system.

The procedure of Example 6 was repeated with the highest ratio of propanol to pyridine, only the portion of the polymer which precipitated out during the reaction was filtered off (precipitate I). Thereon

the mother solution was poured into dilute hydrochloric acid as in Example 6 and the precipitate was separated off (precipitate II). The mother solution separated from the precipitate II was left to stand overnight and the precipitate which had separated out was filtered off. Precipitation I had a softening point of 200 ° C, precipitate II of 145 ° C and 120 ⁰ C. Niederschlaglll of

Example 9

Was the procedure described in Example 1 using other 2,6- or 2,4-substituted Phenols, other copper (I) salts or other tertiary amines were repeated to give the starting phenol corresponding polyphenylene ethers obtained.

The results are summarized in Table IV.

Table IV

Oxidized starting material
(S) Copper (I) salt
(G) Pyridine
(ml) Temperature ⁰ C
Start-max. 75 40 Reaction time
(Minutes) True viscosity 2,6-dimethylphenol Cu ₂ SO ₃ 100 90 30th 0.25 (10) (D 85 64 2,6-dimethylphenol CuOH 125 30th 100 0.19 (10) (1.6)
O 59 64 2,6-dimethylphenol Il
CuOCCH ₃ 100 30th 8th 0.35 (10) (1.2) 41 2,6-dimethylphenol CuClO ₄ 100 30th 12th - (1.6) 56 2,6-dimethylphenol CuBR 125 30th 81 0.91 (10) (2) 56 2,6-dimethylphenol CuN ₃ *) 150 30th 7th 1.13 (5) (D 56 2-methyl-6-ethylphenol CuCI 100 30th 8th 0.29 (5) (D 42 2,6-diethylphenol CuCl 100 30th 8th - (5) (D heated to 90 ° C 2-methyl-6-isopropylphenol CuCl 100 27 20th 0.24 (5) (D heated to 80 ° C 2-chloro-6-phenylphenol CuCl 40 153 - (10) (D 29 2-chloro-6-methylphenol CuCl 125 31 - (5) (1) 25th 2-methyl-6-methoxyphenol CuCl 130 12th 0.27 (3) (1) around 2-allyl-6-methylphenol CuCl 125 giving 12th - (5) (D 2,4-dimethylphenol CuCl 100 9 - (10) (1)

*) The amount was calculated on the basis of the raw material, is explosive.

The first six phenols form poly (2,6-dimethylphenyl-1,4) -ether with the following repeating unit:

The connection cannot be isolated because it is dry

ethylphenyl-1,6) ether. The latter connection would have the following repeating unit:

while the other phenols form depending on the: poly-2- (methyl-6-ethylphenyl-1,4) -ether, poly-2,6-diethylphenyl-1,4) -ether, Poly (2-methyl-6-isopropylphenyl -1,4) - ether, poly - (2 - chloro - 6 - phenylphenyl, 4) ether, Poly (2-chloro-6-methylphenyl-1,4) ether, poly (2-methyl-6-methoxyphenyl-1,4) -ether, poly (2-allyl-6-methylphenyl-1,4 )-ether and poly (2,4-dimewhile the other substances all have repeating units, similar to poly (2,6-dimethylphenyl-1,4) ether, however, their substituents correspond to the name.

In some cases it may be desirable to make a polyphenylene ether of a particular color. This can be done by adding quinones or hydroquinones to the reaction mixture before the oxy-

dation, creating a product that has a built-in color that is made by solvents cannot be removed. This color reaction can be modified to give different shades receives or prevents it entirely. Just like phenols with large voluminous groups in the Ortho position of the ring no polyphenylene ether

can form, so can quinones and hydroquinones, the large voluminous substituents on the ring wear, do not form colored products. Quinones and hydroquinones in which all ring positions are substituted are also unable to form colored compounds if the substituent is not halogen is.

example

The following examples explain the possibilities of preparing polyphenylene ethers from phenols, who have more than one reactive position. The general procedure was as in the example 1 with respect to the preparation of the reaction mixture, the introduction of oxygen and the isolation of the reaction product. In some cases the reaction had to be heated to initiate it. In cases where a solid modifier was present, this was prior to the precipitation of the Polyphenylene ether filtered from the solution. The results are summarized in Table V.

Table V

phenol CuCl Amine solvent Modifiers Temperature C Max. duration Real
viscosity (G) (G) (G) (ml) begin 45 Guiacol 1 2-benzyl pyridine Trichlorethylene 0.1g 30th 91 0.1 (10) (5.2) (40) Picric acid - phenol 1 2-methyl s-tetrachloroethane 0.1g 70 310 0.2 (75) 6-undecyl pyridine (150) Picric acid (5) 50 o-cresol 1 2- (5th-nonyl) - Nitrobenzene - 26th 180 0.39 (5) pyridine (100) (6.2) t-amyl alcohol (10) - o-phenylphenol 1 2-benzyl pyridine Nitrobenzene - 150 155 0.11 (10) (5.1) (125) - m-phenyl 1 s-collidine Tetrachloroethane - 91 111 0.06 phenol (25 ml) (250) (50) 47 o-cresol 1 2-amyl pyridine Tetrachloroethane 4.2 MgSO ₄ 29 86 0.26 (75) (3) (15) (anh) 46 o-cresol 1 2-amyl pyridine Tetrachloroethane 4.29 MgSO ₄ 29 107 0.42 (75) (3) (125) + ig 5% platinum on coals material 32 o-cresol 1 2- (5-nonyl) pyridine Tetrachloroethane 5% Pt 28 1240 0.42 (5) (6.2) (125) carbon (D 50 o-cresol 1 2-amyl pyridine Tetrachloroethane 5% Pt 30th 83 0.48 (7.5) (3) (125) carbon (D 98 o-cresol 2 2-ethyl pyridine - - 30th 9 0.14 (15) 100 ml - o-cresol 3 2- (5-nonyl) - Phenylcellosolv - 50 94 0.3 (15) pyridine (70) (18.5) Benzonitrile (30) - o-chlorophenol 1 2-amyl pyridine Tetrachloroethane 5% Pt 50 145 0.24 (15) (3) (125) carbon Phenylcellosolv (D (65) - o-chlorophenol 1 2-amyl pyridine Tetrachloroethane 5 ml (2% iso- 95 135 0.25 (15) (3) (125) propyl vanadate in Phenylcellosolv Isopropyl (65) nol)

continuation

phenol
(G) CuCl Amine
(G) solvent
(ml) Modifiers Temperature C
Start ■ Max. 40 duration Real
viscosity o-cresol 1 2-amyl pyridine s-tetrachloroethane 4.2 g MgSO ₄ 29 114 0.44 (75) 13) (125) + Ig 5% palla dium on carbon - o-chlorophenol 1 2-amyl pyridine Tetrachloroethane - 98 60 0.12 (15) 13) (125) Phenylcellosolv (65) - o-chlorophenol 3 2- | 5-Nonyi> - Phenylcellosolv - 90 137 0.21 (15) pyrfdin (70) (18.5) Benzonitrile (30)

The reaction product of guiacol (o-methoxyphenol) was poly (2-methoxyphenyl-l, 4) ether, phenol polyphenyl = l _T 4 _T ether of o-cresol = poly (2-methylphenyl-l, 4 ) -ether, from o-phenylphenol = poly ^ -phenylphenyl-1 ^ ätlier, from m-phenylphenol = poly- (3-phenyIphenyJ ~ 1, 4) -ether and from ο - chlorophenol-poly- (2-cMorphenyI -1 , 4) ether. All of these substances consist of recurring units of the same general structure:

in which the numbers indicate the position of the substituents.

* As mentioned earlier, true viscosity is a measure of molecular weight. However, it provides more relative as well as specific measured values. In Table VI some of the ratios measured are given:

Table VI

Polyaryl Ether True Viscosity

Molecular weight according to osmotic

pressure
(Chloroform -25 ° C)

Light scattering

Poly (2,6-dimethyl-1,4-phenyl) ether
Poly (2-methyl-1,4-phenyI) -ether ...
Poly (1,4-phenyl) ether

Poly (2-phenyl-1,4-phenyl) ether
Poly (2-chloro-1,4-phenyl) -ether ..

0.185

2.04

0.19

0.45

0.20

0.15

0.24

16 500
165,000
44,000
63,000
80,000
58,000
41,000
28,000
18 500
47 700
82,000

114,000

678,000

382,000

2,150,000

6,100,000

710,000

66,000 1,220,000 5,400,000

Because of their excellent physical, mechanical, chemical, electrical and thermal Properties There are many and varied uses for the polymers of this invention. So you can z. B. can be used in powder molding compositions, either alone or with various fillers mixed, such as sawdust, diatomaceous earth, carbon black or silica, for the production of pressed parts, such as Spur gears, helical gears, worm or bevel gears, locking devices, bearings, cams, Butt parts, sealing rings, valve seats for high pressure oil and gas systems or other flowable Chemicals that must be resistant to chemicals. They can be used for the production of pressed, calendered or extruded articles, films, coatings, threads, fibers and tapes use. They have a wide range of application as plates, rods or tapes and are Can also be used for electrical purposes, such as cable clamps, terminal blocks, supports for electrical purposes Circuits or as components of dynamo-electric machines that work at high temperatures.

By suitable means such as dissolving or suspending in a suitable solvent and the following Applying to a surface from which the polymer is after evaporation of the solvent removed, by calendering or extrusion, films can be made from these materials. These Films (oriented or not) can be used as linings for metal and plastics, containers, Covers, closures, electrical insulating tapes,

009 542/373

Tapes, pipe and wire wraps. Where a surface is desired that is excellent If the polymer possesses properties, these can be applied to any suitable substrate as a coating material apply in the form of a solution or suspension. They can be used as an encapsulation material, for electrical purposes Insulation, e.g. B. use as wire enamel. They can be put in a precipitation bath as a melt, solution or suspension or evaporation medium extrusion. Leave the fibers so produced (oriented or not) process into fabrics that can be used in many ways, e.g. B. as filter cloths where high chemical and heat resistance is desired. Make their excellent electrical properties Laminates made from this material for electrical purposes. Components usable, such as slot wedges in the armature of a Electric motor, documents for printed circuits, switchboards for electrical devices, radio and television sets, small stamped electrical parts, transformer end plates, spacers for transformer end plates or spacers for transformer coils. The polymers can also be made with different Fillers or modifiers are mixed, such as dyes, pigments, stabilizers and plasticizers.

Claims (2)

Patent claims: 1. A process for the preparation of polyphenylene oxides, characterized in that a copper amine com is produced from a tertiary amine and a copper (I) salt which is soluble in it for 30 ' ilex in the presence of oxygen Temperatures of not more than 100 ^° C. with phenols of the general formulas or OH converts, in which X is a hydrogen, chlorine, bromine or iodine atom, R 'is a halogen atom or R and R represent a hydrogen atom, a hydrocarbon, hydrocarbonoxy, halocarbon or a halohydrocarbonoxy radical, the aliphatic halogenated substituents at least 2 carbon atoms between the halogen atom and the phenol nucleus have all aliphatic substituents at least one hydrogen atom on the carbon atom bonded to the phenol nucleus carry and R and R 'in the general formula II not both a halogen atom or an aryl, May be hydrocarbyl oxy or halocarbon oxy radical. 2. The method according to claim 1, characterized in that there is used phenols in which R denotes a methyl or phenyl radical.