DE2336090A1 - PROCESS FOR THE PRODUCTION OF DIPHENYLAETHERS - Google Patents

Description

YEB CHEMIEKOMBIMÄI BIT'IERFBuD Bitteri'eld, 10, 4. 1973

1674

Inventor: Dr "Günther Eßbach, Dessau ■ 'Dr ♦ I''alko Fahrigen, Halle

Dr ₀ Werner. Kochmann, Wolfen Dr ₀ Hans-Peter ^ orthals, Dessau Diplo-Chem, Hans-Günter Kratochvil, Halle Dr ₀ Hans Schilling, Sandersdorf Dr ₀ Siegfried Schumann, Holzweißig Diple-Ghenio -Surt 'Trautner, Bitterfeld Diplo-Ghenio Günter "Volt, Bitterfeld.

Process for the production of diphenyl ethers

The invention relates to a method of manufacture of substituted diphenyl ethers of the general formula '

in which X denotes a halogen or an alkyl, alkoxy or alkylamino group containing 1 to 3 carbon atoms, where the substituents X present in the molecule can be identical or different, and where η is an integer from 0 to "2, m 1 or 2 and ρ and q, which can be οάνι- var ;; chleden,

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represent an integer from 0 to 3. These connections are optionally substituted Phenols, substituted chlorobenzenes and 'potassium hydroxide represented they can be used for Example as intermediate products · for dyes and textile protection agents | as a pesticide as well for various other areas of application.

The previously known method for. Production of Diphenyl ethers are based on the Ullmann reaction. The starting materials are left in the molten state React state in the presence of copper powder. Iron powder or aluminum oxide are also used as a catalyst recommended. ■

One of the major drawbacks of such procedures is there in the fact that the condensation of the reactants leads to a sudden, strongly exothermic deflagration the entire reaction mixture can come. Pressure rise rates of 10 to 100 at / s and temperatures of 350 ° 0 and above appear.

In addition, about 10% of the resinous products, which are natural, are formed in the reaction by such methods reduce the yield and make reuse of the catalyst practically impossible.

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- 3 -'- 'There are too. Known what the Reaction in miscible with water mostly also strong Polai "en solvents run off. As a solvent · are mainly dimethyl sulfoxide or dimethyl formamide uses me iac with the same cata- · analyzers as before * Also known is the through., conduct of the reaction in giols or their ethers. > ■

The work-up is usually carried out in such a way that the reaction mixture is pressed into water or dilute aqueous alkali, with the desired .Product and a large part of the unwanted by-products are firmly deposited * It arises at the same time. a wastewater containing the inorganic reaction products, contains the unreacted, optionally substituted phenols and, in spring cases, the solvent. · Recovery of the solvents is technically extremely complex and expensive, for example possible through a multi-stage Koloühendestiliation. If there is no recovery, - the relatively expensive solvents are lost. Wear at the same time these often poisonous substances, 'such as Dimethylformamide, for environmental pollution and poisoning of the rivers. ·.

It is also known that the above solvents are not absolutely inert in the implementation

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y get _o So is. For example, dimethyl sulfoxide at the reaction temperatures used is partly thermal, unstable "Glycol can react with the reactants used to form undesirable mixed ethers", · '

The purpose and purpose of the invention was therefore, Process for the preparation of substituted diphenyl ethers to find one that runs completely safely once, that when working with solvents, such that can be recovered as completely as possible, and that as few losses as possible due to undesired « By-products brings

It has now been found that substituted diphenyl ethers can be used the general formula

where X is a halogen or an alkyl, alkoxy or alkylamino group containing 1 to 3 carbon atoms, where the substituents X present in the molecule can be identical or different, and where η is an integer from 0 to 2, m 1 or 2 and ρ and q, which may be the same or different, represent an integer from 0 to 3, selected from substituted halobenzenes

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the more general! formula

II

with phenols of the general formula

III

where Hai means halogen "and X, n, m, ρ and q have the meaning given above, can be produced with the addition of aqueous potassium hydroxide solution if the reaction of the 3 components phenol, substituted halobenzene and aqueous potassium hydroxide solution in the presence of chlorinated aromatic compounds so carries out that the component to be added last, the substituted halobenzene, aqueous potassium hydroxide solution or the potassium phenolate solution obtained from aqueous potassium hydroxide solution and phenol can be, at a temperature between the boiling point of the azeotropic mixture of the chlorinated aromatic compound and water and 1BO ° 0 in portions or continuously added distributed over a period of 2 to 6 hours, with any water present being largely removed azeotropically,

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after which by separating the inorganic constituents ■ The diphenyl ether obtained and distilled under vacuum will·

The process are called chlorinated aromatic compounds the monochlorobenzene as well as 1,2-dichlorobenzene, Isomer mixtures of dichlorobenzenes or mixtures of monochlorobenzene with dichlorobenzenes, 1,2, ^ - trichlorobenzene, mixtures of trichlorobenzenes, Mixtures of different highly chlorinated benzenes, 1- or 2-chloronaphthalene, mixtures thereof or mixtures of ChlorneBithalinen with different levels of chlorination Suitable for benzenes »

For the leadership of the Heaktion turned out to be special favorable the use of o-dichlorobenzene containing Mixtures, the use of technical grade o-dichlorobenzene or the use of pure o-dichlorobenzene.

The amount of chlorinated aromatic compounds to be added can be varied within wide limits For a batch to produce 1 mole of diphenyl ether, an amount of preferably about -150 ecm can be chlorinated aromatic compounds are used · Too large amounts are uneconomical. For quantities significantly below 75 ecm one approaches the known processes in the melt,

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which bring with them the risk of a deflagration. It was found that when working "in chlorinated aromatic compounds the addition of catalysts such as copper powder »iron powder or Alumina is not necessary. '_.'_ ".

In detail, the procedure is that in chlorinated ■ aromatic. Compounds 0.8 to 1.4-mol, preferably 1.2 mol, substituted halobenzene solves at 100 to 180 ⁰ O and heated to an optionally from 20 to 100 ⁰ g of aqueous solution of 1.02 to preheated - "!, 2 mol, preferably 1.05 mol, optionally substituted phenol and 1 mol KOH are metered in within 1 to 6 hours and stirred for a short time. During the reaction, the water distills azeotropically with the chlorinated aromatic compounds and is removed with the aid of a water separator it is also possible to introduce the optionally substituted potassium phenolate in the chlorinated aromatic compounds and to meter in the substituted halobenzene.

Another possibility is to use the optionally sub- substituted phenol and the substituted chlorobenzene and add aqueous potassium hydroxide solution.

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The reaction mixture is worked up by Neutral spots with mineral acids and filter off the Salts. The filtrate is partially distilled or distilled in vacuo. With this method, no saline wastewater falls at.

Another possibility is to cool the reaction mixture to about 100 ⁰ G in dilute alkali, preferably 1%. Sodium hydroxide solution, to be pressed in, the organic phase to be separated off and to be distilled or distilled in vacuo. Unreacted, optionally substituted phenol can be recovered from the aqueous phase by steam treatment.

The inventive method has the advantage that to avoid possible exothermic explosive decomposition in the previously known method.

This behavior of the reaction mixture is due to * justifies that local overheating is excluded by the solvent. In the event of an exothermic The breakdown of traces of by-products is the amount of energy released by the heat capacity of the chlorinated aromatic compounds captured; optionally the solvent distills, Ein Temperature rise to values at which the exothermic decomposition of the entire reaction mixture takes place

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could, is therefore excluded «Even if they differ significantly from those in the following examples Conditions (higher reaction temperature, overdosing of the individual reactants, long thermal stress the reaction mixture ('addition of metals' and metal salts) undergoes exothermic decomposition not on β ■ '.

The use of catalysts is not necessary. »The chlorinated aromatic compounds used as solvents can be completely recovered and reused. This is mainly due to the fact that they are not soluble in water. During the reaction itself they behave inertly · The unreacted reaction components can also be · recovered during work-up . ■ ■ '"■

It was also found that in the reaction the usual amount of resin to a quarter, however, at least be reduced by half, which leads to a noticeable increase in yield.

The invention is further explained using the following exemplary embodiments,

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Example 1: ·

112 g (2 mol) of potassium hydroxide and 291.9 g (2.1 mol) of o-nitrophenol are added in portions to 150 ml of water while stirring. This solution of o-nitrophenolkaliuin thus obtained. in water is kept at a temperature of 85 ⁰ O and continuously added dropwise over 4 hours with stirring to a ^{heated to 130 0} C solution of 34-6.5 S (2.2 mol) of o-nitrochlorobenzene in 300 ml of chlorobenzene. During the reaction, the ^{water which is azeotropically distilling 1} with the solvent is removed with the aid of a water * separator. After the addition is complete, the mixture is stirred for a further 10 minutes, cooled and neutralized with 7 parts of concentrated sulfuric acid. The precipitated salt mixture (KCl / iUSO.) Is filtered off with suction and the filtrate is distilled off in vacuo. The solvent is obtained as the forerun and a mixture of o-prophenol and o-nitrochlorobenzene as the second fraction. The residue obtained is 416.2 g crude 2.2 ^f -dinitra- ■ diphenyl ether

Example 2:. .

From 56 ml of water, 112 g (2 mol) of potassium hydroxide and 226.8 g (2.1 mol) of "o-cresol are obtained according to Example 1 a dark, clear solution of o-cresol potassium in water. This solution, cooled to room temperature, drips

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with stirring to a ^{heated to 145-150 0} O solution of 346.5 g (2.2 mol) of o-Uitrochlorbenz.ol in 300 ml of technical grade 1,2 dichlorobenzene continuously over 4 hours. After working up as in Example 1 are obtained in the vacuum distillation at a boiling point of Kp ₀ "= 140 ° 0, 352 g.reinen 2-M.tro-2 ^f _o -methyldiphenylather

Example 3 .:. · '

At 175-180 ⁰ C is added dropwise with stirring to a solution of 346.5 g (2.2 moles) of p-Nitr.ochlorbenzol _ in 300 ml technischem'1,2-dichlorobenzene GemiBch (contains about 80% _e 1, 2-dichlorobenzene, about 20% 1,4-dichlorobenzene) from a previously ml 56 of water, 112g (2 mol.) of potassium hydroxide and 342,3g (2.1 mol prepared) 2,4-dichlorophenol and heated to 95 ⁰ G Solution of 2,4-dichlorophenol potassium continuously within 4 hours. Working up is carried out as in Example 1. The vacuum distillation gives 420 g of 4-nitro-2 », 4 ^f -dichlorodiphenyl ether _{at a boiling point of bp n} ~ _c = 151 ^{0 O,} .

Example 4: ■

300 ml of a 1,2-dichlorobenzene mixture, 346.5 g (2.2 moles) of p-hydrochlorobenzene and 342.3 g (2.1 moles) 2,4-dichlorophenol to 175-180 heated and a solution within 4 hours

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of 112 g (2 mol) of potassium hydroxide in 120 ml of water are added dropwise; · During the reaction, the azeotropically distilling water is continuously removed · It is worked up as in Example 1 and distilled under vacuum »At a boiling point of bp _n ; = 168 ⁰ C, 418 g of 4-.lTitro-2 ^I _f 4 ^t -dichlorodiphenyl ether are obtained »22 g of resinous residue remain in the still

Example 5 ί

From 112 g of water, 112 g (2 mol) of potassium hydroxide and 197 »4- g (2.1 mol) of phenol, according to Example 1, a dark, clear solution of phenol potassium in water is obtained. This cooled to room temperature solution was continuously added dropwise to a stirred heated to I30 ⁰ O solution of 445.5 g (2.2 mol) of 2,4-dinitrochlorobenzene in 300 ml Ghlorbenzol within 3 hours and stirred for 30 minutes after "After Working up as in Example 1 gives 39Ο g of 2,4-dinitrodiphenyl ether in vacuum distillation at a boiling point of Ep _no = 173-174 ^{0 G.}

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Claims (2)

.Patent claims: 1 _#v ) Process for the preparation of substituted diph.enylath.ern- of the general formula wherein X is a halogen or 1 to 3 carbon atoms denotes containing alkyl, alkoxy or alkylamino groups, where the substituents present in the molecule X can be the same or different, and where η is an integer from 0 to 2, i1 or and ρ and q, which can be the same or different, represent an integer from 0 to 3, from substituted halobenzenes of the general formula - (II) with phenols of the general formula ^ Γ ~ ^ ν_0Η _t - (HI) 409844/0970 where Hal is halogen and X, η, m, ρ and q have the meaning given above, with the addition • of aqueous potassium hydroxide solution, characterized in that the reaction of the 3 components phenol, substituted halobenzene and aqueous potassium hydroxide solution in the presence of chlorinated aromatic compounds is carried out in this way. carries out that the component to be added last, the substituted halobenzene, aqueous potassium hydroxide solution or the ^; Potassium phenolate solution obtained from aqueous potassium hydroxide solution and phenol can be added at a temperature between the boiling point of the azeotropic mixture of the chlorinated aromatic compounds and water and 180 ⁰ C in portions or continuously .. over a period of 2 to 6 hours, where appropriate if present Water for the most part azeotrope is removed, after which through. Separation of the inorganic constituents and distillation under vacuum ■ Diphenyl ether is obtained. 2. The method according to claim 1, characterized in that the chlorinated aromatic compounds monochlorobenzene, 1,2-dichlorobenzene, isomer mixtures of dichlorobenzenes, 1,2,4-trichlorobenzene, mixtures of trichlorobenzenes, mixtures of different high 'chlorinated benzenes, 1- or 2 -Ohlornaphthalene, • Mixtures of the same or mixtures '4 0-9 844/0970 -. of chloronaphthalenes with different levels chlorinated benzenes, preferably 1,2 dichlorobenzene or mixtures with 1,2-pichlorobenzene, in 'amounts of preferably about 150 ecm per • Approach to the production of 1 mole of diphenyl ether be used,, ' . . Process according to claims Λ and 2, characterized in that the inorganic constituents are separated off by neutralization with concentrated mineral acids and the amounts of salt formed are removed from the reaction mixture, 4-, Process according to Claims 1 and 2, characterized in that the inorganic constituents are separated off by pouring the reaction mixture into dilute lye and separating off the aqueous phase. Rbg / E 409844/0970