DE2123349A1 - Alkylphthalic acids by epoxidation of alkyltetrahydroanthraquinones - and hydrolysis and oxidation of epoxides - Google Patents

Abstract

Alkylphthalic acids (II) (where R1 to R4 H or lower, pref. 2 - 5C, alkyl and all constituents together contain is not >10C if iso-alkyl groups are present), are produced by epoxidation of alkyltetrahydroanthraquinones, particularly as obtained in anthraquinone process, to alkyltetrahydroepoxyanthraquinones (I) which are oxidised to (II) under hydrolysis, or in pref. process, (I) is first hydrolysed to an alkyltetrahydrodihydroxyanthraquinone, pref. a cis-(8a,10a)-H-(8a,10a)-dihydroxyketone (III) which is oxidised to (II) in a separate reaction step in an alkaline medium. Process is useful for working up undersired byproducts from anthraquinone process for H2O2 production to produce (II), particularly mono- and dialkylphthalic acids and adipic acid. 4-Alkylphthalic acids are intermediates for alkyl-anthraquinone dyes. (II) can further be molten with urea and a metal salt to form tetra-alkyl phthalocyanines, particularly tetra-t-butyl phthalocyanine, which is soluble in aliphatic and aromatic hydrocarbons, and is useful as oxidation catalyst, for example in fuel cells.

Description

Process for the preparation of alkylphthalic acids The present invention relates to a process for the preparation of alkylphthalic acids by hydrogenation of AlkyltetrahydroanthrachwnonenO The process is characterized in that one Alkyltetrahydroanthraquinones too. Alkyltetrahydroepoxyanthraquinones epoxyd'ert.

The process of the invention also relates to the work-up of undesired by-products which arise in the context of the anthraquinone process for the production of hydrogen peroxide and related processing and their refinement. Alkylphthalic acids are understood as meaning mono- and polyalkylphthalic acids, but preferably mono- and dialkylphthalic acids. These are alkylphthalic acids According to process (a), hydrolysis and oxidation of the epoxide (I) are carried out in one reaction step. In process (b) the epoxide (I) is hydrolyzed to the double ketol (III) and this is oxidized in a separate reaction stage to give alkylphthalic acid (11).

In the formulas given, R1 to R4 are independently of one another Hydrogen or low molecular weight, preferably 2 to 5 carbon atoms containing alkyl, where branched alkyl groups are the number of carbon atoms of all substituents is not more than 10.

The conversion of the alkyltetrahydroanthraquinones into the alkyltetrahydroepoxyanthraquinones (1) is more expedient - «- Ten wise in water-containing organic solvents in the presence of alkaline catalysts by hydrogen peroxide or hydrogen peroxide emitting substances made at elevated temperature, this epoxidation is advantageous in an oxidation-stable, water-miscible solvent, for example in Methanol, acetone or dioxane. As alkaline catalysts for the Epoxidation can be ammonia, aliphatic amines, alkali acetates, alkali carbonates, Alkaline hydroxides, as well as quartz ammonium hydroxides, can be used. The temperature range for epoxidation lies between room temperature and the boiling temperature of the one used Solvent, but preferably between 40 and 800C, The further oxidation the epoxies (I) in process (a) is given off with oxygen Substances, preferably emitting hydrogen peroxide or hydrogen peroxide Fabrics. This procedure leads to solutions of alkyl tetrahydroanthraquinones in a water-miscible solvent, hydrogen peroxide or hydrogen peroxide releasing substances and aqueous alkalis are added at an elevated temperature. As a solvent For example, dioxane, acetone and low molecular weight alcohols are particularly effective Methanol and ethanol. The addition of emulsifiers also proves to be advantageous, e.g. of sulphonated alkylnaphthalenes.

According to method (b), the epoxies (I) are through before oxidation Treatment with alkalis or acids to the xetols (III) hydrolyzed and these im oxidized in an alkaline medium. As oxidizing agents are again advantageous Hydrogen peroxide or substances emitting hydrogen peroxide, oxygen or oxygen emitting substances, e.g. potassium permanganate or lead dioxide are used.

Adipic acid is used as a by-product in the process according to the invention However, easily obtained from the Alkylphthalic acid can be modified is. The separation can, for example, after anhydridization of the alkylphthalic acid at elevated temperature by extraction of the allrylphthalic anhydride or by Treating the mixture with alkali carbonates, leaving only the adipic acid in solution or by esterification and separation of the esters by distillation. The severed one Aidpic acid is used as a starting material for polymers or as a filler in the tannery usable.

In detail, the process of the invention is particularly advantageous in such a way that the alkyltetrahydroanthraquinones are in the oxidation-resistant solvent, E.g. acetone suspended and with vigorous stirring at the boiling point of the solvent slowly diluted alkyl hydroxide and 30 to 40 percent hydrogen peroxide in the stoichiometrically required amounts are added dropwise. To the same extent as epoxidation As the alkyltetrahydroanthraquinone progresses, it goes into solution. After complete Epoxidation, the solvent is distilled off, a higher-boiling solvent mediator is added, e.g. dioxane and those used to form the disodium salt of alkylphthalic acid and the Adipic acid theoretically required amount of 35 to 70 percent Alkali hydroxide to and heated with vigorous stirring to the boiling point of the mixture, whereby one 35 to 70 percent hydrogen peroxide is slowly added dropwise. Then it is distilled the solubilizer, e.g. dioxane, filtered from small fractions if necessary Epoxy that has not been degraded, mixed with the amount required for acid formation of acid and evaporates to dryness. Remove the organic from the dry residue Acid in a solvent, e.g. acetone, evaporates this off and a mixture is obtained from alkylphthalic acid and adipic acid. The separation of the alkylphthalic acid from the Adipic acid is made by heating to at least 1100C, which dag the anhydride Alkylphthalic acid is formed.

The water of reaction is distilled off, the alkylphthalic anhydride dissolved out of the melt with a solvent, e.g. benzene, while the Adipic acid remains undissolved. The crude alkylphthalic anhydride is then used distilled and can be converted directly into the diester.

However, the epoxides (I) are hydrolyzed to the double ketols (III) and oxidized to alkylphthalic acids (II) in a separate reaction stage, then takes place taking the hydrolysis in either dilute acids or alkalis Pressure. The hydrolysis can also be carried out in 75 to 90 percent sulfuric acid, with drive until the epoxy has dissolved. The ketols are precipitated from this solution by adding a little hydrogen peroxide and water. You will then be in the alkaline Medium with the theoretically required amount of potassium permanganate or lead dioxide or hydrogen peroxide or by introducing oxygen at elevated temperatures oxidized to alkylphthalic acids, which by one of the processes given above by the adipic acid can be separated.

The alkyltetrahydroanthraquinones required for the proposed process are very easily alkylated anthraquinones by hydrogenation of the nucleus obtained, since the hydrogenation of alkylated anthraquinones specifically on the non-alkylated Core starts. 2-Alkyl-5,6,7,8-tetrahydroanthraquinones are particularly easily accessible, e.g. 2-ethyl- or 2-tert-butyl-5,6,7,8-tetrahydroanthraquinone, as these substances as part of the "anthraquinone process" for the production of hydrogen peroxide 2-alkylanthraquinones (2-ethyl- or butylanthraquinone) are formed and themselves enrich in the working solutions. From these 2-alkyltetrahydroanthraquinones develop again in the presence of hydrogen peroxide the epoxies (I) as for the arthraquinone process unwanted by-products. Thus, the residues of old working solutions particularly advantageous by the process according to the invention to give 4-alkylphthalic acids and adipic acid are worked up.

For example, one obtains from 2-ethyl-5,6,7,8-tetrahydroanthraquinone containing working solutions 4-Aethylphthalsåure, from -2-tert. -Butyl-5, 6,7, 8-tetrahydroanthraquinone containing working solutions 4-tert. -Butylphthalic acid in pure form and high Yield in addition to adipic acid. Alkyl anthraquinone dyes can be obtained from 4-alkylphthalic acids produce. Furthermore, by fusing the manufactured according to the invention Alkylphthalic acids produced with urea and a metal salt tetraalkylphthalocyanines will. These TetraalkylphthalGcyanine but especially Tetra-tert. -butylphthalocyanine, prove themselves because of their good solubility in aliphatic and aromatic hydrocarbons as western; -full oxidation catalysts-e.g. for fuel cells.

The present invention also relates to the Ci- 8a - loa - H - 8a - loa - dihydroxydiketones of the formula where R1 to R4, independently of one another, denote hydrogen or low molecular weight alkyl, preferably containing 2 to 5 carbon atoms, and if branched alkyl groups are present, the number of carbon atoms of all substituents is not more than 10.

These compounds have as directly tangible intermediates for the production of alkylphthalic acids on the synthetic route outlined (b) Significance.

They are solid bodies with the characteristic of the hydroxyl group IR band that can be extracted from solvents such as petroleum ether or from mixed solvents 2-Ethyl-5,6,7,8-tetrahydro- (cis-) 8a-loa-H-8a-loa-d-hydroxyanthraquinone can be recrystallized FP 1070C (acetone / cyclohexane prisms) 2-tert-butyl-5,6,7,8-.tetl-ahydro (cis) 8a-loa-H-8a-loadihydroxyanthraquinone ' FP 1220C (needles made of petroleum ether).

With alkalis or acids, the epoxides (I) become the cis-diketols split. Only these can be converted into alkylphthalic acids with oxygen-releasing substances oxidize.

The parts given in the examples are parts by weight. The temperatures are given in degrees Celsius.

Example 1: Production of 4-ethylphthalic acid a) Production of 2-ethyl-5,6,7,8-tetrahydro-8a-10a-H-8a-10a-epoxyanthraquinone: 240 parts of 2-ethyl-5,6,7, 8-tetrahydroanthra quinone are suspended in 1000 parts of acetone and placed in a water bath (Badtem. 560) initially 10 parts of aqueous hydrogen peroxide with intensive stirring (35 parts of hydrogen peroxide per 100 parts) and then at the same time 120 Parts of aqueous sodium hydroxide solution (12 parts of NaOH to 100 parts) and 240 parts of aqueous Hydrogen peroxide (35 parts of hydrogen peroxide to 100 parts) was added dropwise. The speed the Addition for caustic soda should be 0.5 parts / minute, for hydrogen peroxide 1 part per minute is Na2h after the hydrogen peroxide has been added, the mixture is stirred intensively for two hours and then the acetone is distilled off. The residue, consisting of dilute sodium hydroxide solution and the epoxy is further processed under b).

b) The residue from a) is mixed with 320 parts of aqueous sodium hydroxide solution (50 parts of NaOH to 100 parts) and 150 ml of dioxane were added. One then heats under Reflux to the boil and drop 260 parts of aqueous hydrogen peroxide with vigorous stirring (65 parts hydrogen peroxide to 100 parts). The addition of the hydrogen peroxide should be done at a speed of 2 parts / minute. Then distilled if the dioxane is removed, any insoluble organic residues are separated off and add 4.5 moles of hydrochloric acid or the corresponding amount of another mineral acid and evaporates to dryness. To convert 4-ethylphthalic acid into its anhydride, the residue is heated to 1500 in vacuo and the water of reaction is drawn off. Thereafter it is extracted with benzene and the crude 4-AethylphthalsSureanhydrid is distilled in Vacuum. (Yield 86%). Adipic acid can be made from the salt residue be won. 4-Ethyl pnthalic acid is obtained from the anhydride by saponification.

Example 2: Production of 4-tert. -Butylphthalic acid 268 parts of 2-tert, -Butyl-5,6,7,8-tetrahydroanthraquinone are suspended in 800 parts of acetone and on a water bath (Badtem. 560) with intensive First stir 10 parts of aqueous hydrogen peroxide (35 parts of hydrogen peroxide to 100 parts) and then at the same time 120 parts of aqueous sodium hydroxide solution (12 parts of NaOH to 100 parts) and 240 parts of aqueous hydrogen peroxide (35 parts Hydrogen peroxide to 100 parts) was added dropwise. The speed of addition for the sodium hydroxide solution should be 0.5 parts / minute, for the hydrogen peroxide 1 part / minute be. After the hydrogen peroxide has been added, the mixture is stirred vigorously for two hours further and then the acetone is distilled off. The residue consisting of dilute sodium hydroxide solution and the epoxy is mixed with 320 parts of aqueous sodium hydroxide solution (50 parts of NaOH to 100 parts) and 150 ml of dioxane were added.

The mixture is then heated to boiling under reflux and dripped under vigorous Stir 260 parts of aqueous hydrogen peroxide (65 parts hydrogen peroxide to 100 parts).

The addition of the hydrogen peroxide should be carried out at one speed of 2 parts / minutes follow. The dioxane is then distilled off and, if necessary, separated insoluble organic residues and gives 4.5 mol hydrochloric acid or the equivalent Amount of another mineral acid and evaporate to dryness. The residue will heated to 1500 for anhydride in vacuo and the water of reaction was distilled off. It is then extracted with benzene and the crude 4-tert-butylphthalic anhydride is distilled in vacuo (yield 83%). By saponifying the anhydride with water, 4th-tert-butylphthalic acid is obtained. Adipic acid can be obtained from the salt residue.

Example 3: Preparation of 4-amylphthalic acid, 278 parts of 2-amyl-5, 6,7,8-tetrahydroanthraquinone are suspended in 800 parts of acetone and placed in a water bath (Bath temp. 560) with intensive stirring initially 10 parts of aqueous hydrogen peroxide (35 parts of hydrogen peroxide to 100 parts) and then at the same time 120 Parts of aqueous sodium hydroxide solution (12 parts of NaOH to 100 parts) and 240 parts of aqueous Hydrogen peroxide (35 parts hydrogen peroxide to 100 parts) added dropwise.

The rate of addition for the caustic soda should be 0.5 parts / minute, for the hydrogen peroxide be 1 part / minute. After the hydrogen peroxide has been added The mixture is stirred intensively for a further two hours and then the acetone is distilled away. The residue consisting of dilute sodium hydroxide solution and the epoxy is mixed with 320 Parts of aqueous sodium hydroxide solution (50 parts of NaOH to 100 parts) and 150 ml of dioxane are added. The mixture is then heated to boiling under reflux and 260 is added dropwise with vigorous stirring Parts aqueous hydrogen peroxide (65 parts hydrogen peroxide to 100 parts) to. The addition of the hydrogen peroxide should be at a rate of 2 parts / minute take place. The dioxane is then distilled off and any insoluble ones are separated off organic residues and gives 4.5 mol of hydrochloric acid or the corresponding amount Mineral acid and evaporated to dryness. The anhydride is heated The residue is reduced to 1600 in vacuo and the water of reaction is drawn off. Then extract with benzene and the crude 4-amyiphthalic anhydride is distilled in vacuo. (Yield 85%).

By saponifying the anhydride with water, 4-amylphthalic acid is obtained. Adipic acid can be obtained from the salt residue be won.

Example 4: Degradation of the 2-ethyltetrahydroanthraquinone epoxide via 2-Ethyl-5> 6.7, 8-tetrahydro-8a-10a-H-8a-i0adihydroxyanthraquinone to 4-ethylphthal acidic 25 parts of 2-ethyltetrahydroanthraquinone epoxide are diluted 2n = O parts Sulfuric acid (85 parts of sulfuric acid to 100 parts) entered and stirred at 400, until everything is resolved. Then one drips to this solution under good Slowly stir 4 parts aqueous hydrogen peroxide (35 parts hydrogen peroxide to 100 parts) and then diluted with 100 parts of water, the 2-ethyltetrahydro-8a-10a-dihydroxyanthraquinone fails. This is filtered off and 100 parts of dilute sodium hydroxide solution are added (20 parts of NaOH to 100 parts) and 25 ml of hydrogen peroxide are added dropwise at the boiling point (65 parts to 100 parts). Then one sets with the equivalent amounts Hydrochloric acid or another mineral acid releases the 4-ethylphthalic acid and evaporates Dry and anhydrate the residue by heating in vacuo to 1500. Man extracted with benzene and distilled the 4-ethylphthalic anhydride in the Vacuum. 4-Ethylphthalic acid can be obtained from the anhydride by saponification will.

Example 5: Preparation of), 5-diethylphthalic acid 268 g of 1,3-diethyl-5,6,7,8-tetrahydroanthraquinone are suspended in 1000 parts of acetone and treated with 120 parts of aqueous sodium hydroxide solution (12 parts of NaOH to 100 parts) and 240 parts of aqueous hydrogen peroxide (35 parts Hydrogen peroxide per 100 parts) treated as in Example 1 a). The further dismantling to 3,5-diethylphthalic acid is carried out analogously to Example Ib).

Example 6: Degradation of 2-ethyltetrahydroepoxyanthraquinone in the presence of isopropanol as a solubilizer to 4-ethylphthalic acid 240 parts of 2-ethyl-5,6,7, 8-tetrahydroanthraquinone are converted into 2-ethyltetrahydroepoxyanthraquinine analogously to Example la) convicted. After evaporation of the acetone, the residue, consisting of dilute Sodium hydroxide solution and the epoxy mixed with 360 parts of isopropanol and refluxed heated to the boil, at the same time dripping into the boiling solution while stirring vigorously 320 Tel le aqueous sodium hydroxide solution (50 parts NaOH to 100 parts) and 320 parts of aqueous hydrogen peroxide (65 parts of H202 to 100 parts). The duration the addition should take about 2 hours. The isopropanol is then distilled off, filtered with the addition of 1 g of animal charcoal and acidified the filtrate with 4> 5 mol Hydrochloric acid. It is evaporated to dryness and the residue on in vacuo 1500 heated and the resulting water of reaction run3 drawn off to the 4-ethylphthalic acid to convert anhydride into it. The 4-ethylphthalic anhydride is extracted from the residue with benzene and purify it by distillation (yield 95%). From the salt residue adipic acid can be obtained.

Example 7 Degradation of a residue from circulatory solutions of the anthraquinone process to 4-ethylphthalic acid.

The residue used for degradation consisted of 42 parts of 2-ethyltetrahydroanthraquinone, 45 parts of 2-ethylanthraquinone, 10 parts of 2-ethyltetrahydroepoxyanthraquinone and 11 Parts of unidentified components.

108 parts of this residue were added to 450 parts acetone and 10 parts of hydrogen peroxide (35 parts of H 2 O 2 to 100 parts) were then added while stirring vigorously on a water bath (bath temperature 560) at the same time 31 parts of aqueous Sodium hydroxide solution (12 parts of NaOH to 100 parts) and 60 parts of hydrogen peroxide (35 parts H202 per 100 parts) was added dropwise within one hour.

After the addition of hydrogen peroxide and alkali, the batch was started stirred intensively for a further 3 hours at 56 ° water bath temperature. After that, the acetone distilled off, the residue is mixed with 120 ml of isopropanol and refluxed heated to boiling. In the boiling solution were simultaneously with vigorous stirring 75 parts of aqueous hydrogen peroxide (70 parts of H202 to 100 parts) and 75 parts aqueous sodium hydroxide solution (50 parts of NaOH to 100 parts) was added dropwise over the course of 40 minutes. The isopropanol was then distilled off and, after cooling, the solid precipitate, consisting of 2-ethylanthraquinone separated. The filtrate was treated with 1.1 mol of hydrochloric acid added, evaporated to dryness and the residue anhydridized at 1500 in vacuo.

The 4-ethylphthalic anhydride was dissolved out with benzene and purified by distillation.

There were 42 parts of 2-ethylanthraquinone and 34 parts of 2-ethylphthalic anhydride obtain.

Claims (6)

Claims Process for the production of alkylphthalic acid, characterized in, that one can alkyltetrahydroanthraquinones, especially as they are in the anthraquinone process incurred, epoxidized to alkyltetrahydroepoxyathraquinones and these under hydrolysis oxidized to alkylphthalic acids. 2. The method according to claim 1, characterized in that the Epoxides hydrolyzed to alkyltetrahydrodihydroxyanthraquinones and these in one oxidized to alkylphthalic acids in a separate reaction stage in an alkaline medium. 3. The method according to claim 1, characterized in that the Epoxy oxidized with alkaline hydrogen peroxide to form alkylphthalic acids. 4. The method according to any one of claims 1 to 3, characterized in that that the hlkyltetrahydroepoxyanthraquinones in the presence of a Ljungsvermittlers oxidized with hydrolysis to alkylphthalic acids. 5. The method according to claim 4, characterized in that as LUsungsmittler one or more secondary or tertiary alcohols can be used. 6. A cis- (8a> 10a) -H- (8a, loa) -dihydroxydiketone of the formula where R1 to R4, independently of one another, denote hydrogen or low molecular weight alkyl, preferably containing 2 to 5 carbon atoms, and if branched alkyl groups are present, the number of carbon atoms of all substituents is not more than 10.