Preparation method of aromatic diether dianhydride

Abstract

The invention discloses a preparation method of aromatic diether dianhydride, which comprises the following steps: S1, feeding: adding a dihydroxyl monomer, an alkaline compound, a transition metal complex catalyst, an organic solvent and a water diversion agent into a reaction container, and continuously introducing inert gas; s2, water separation: raising the temperature to separate out water in a reaction system; s3, etherification reaction: adding a nitrophthalimide derivative, raising the temperature to carry out etherification reaction, filtering after the reaction is finished, and carrying out reduced pressure distillation on filtrate to remove the solvent, so as to obtain an etherified product; and S4, carrying out hydrolysis ring opening, acidification and dehydration ring formation on the etherification product to prepare the aromatic diether dianhydride. According to the preparation method of the aromatic diether dianhydride, the specific catalyst is introduced in the etherification reaction stage, a high-selectivity catalytic system is formed, generation of by-products can be effectively inhibited, the yield and purity of target etherified products are remarkably improved, tedious steps of etherification and purification are avoided, the total preparation process is simplified, and the preparation method is suitable for industrial production.

Description

Technical Field

[0001] This invention relates to the field of chemical technology, specifically to a method for preparing aromatic diether dianhydrides. Background Technology

[0002] Polyetherimide (PEI), as a high-performance specialty engineering plastic, exhibits excellent heat resistance, mechanical properties, and electrical characteristics due to the unique combination of rigid aromatic rings and flexible ether bonds in its molecular structure, and has been widely used in aerospace, automotive manufacturing, and other fields. The core of PEI synthesis lies in the preparation of the monomer aromatic diether dianhydride (represented by bisphenol A diether dianhydride BPADA), but the industrialization process of this monomer has long been limited by the efficiency and cost bottlenecks of the synthesis process.

[0003] Currently, there are two main technical routes: one is the halogenated phthalic anhydride route, such as the synthesis methods using bisphenol A and chlorophthalic anhydride as raw materials disclosed in Chinese patent applications CN104529966A and CN108148029A. Although some optimization has been made in the reaction stage, the yield is still low. Moreover, the chloride ion byproducts generated in this route can cause serious corrosion to the equipment, placing high demands on the reactor material and hindering industrial production. The second is the traditional phthalic anhydride route, which uses phthalic anhydride, an amino protecting agent, and bisphenol A as raw materials. Although this avoids the halogen corrosion problem, it requires multiple steps such as amination, nitration, etherification, hydrolysis, acidification, and dehydration (as shown in the reaction formula below). The process is lengthy, and the numerous byproducts lead to low phase separation efficiency. Especially in the etherification stage, poor reaction selectivity can cause oxidation and ring-opening of the raw materials and non-target coupling side reactions, resulting in low overall yield and low product purity. Post-processing steps are required to remove impurities, significantly increasing production costs.

[0004]

[0005] It is evident that, for the preparation of aromatic diether dianhydrides, although the traditional phthalic anhydride route has advantages in avoiding halogen byproducts, the low selectivity and low yield of its etherification stage remain the core obstacles restricting industrialization. Summary of the Invention

[0006] In order to overcome the shortcomings of the existing technology, the present invention aims to provide a method for preparing aromatic diether dianhydride, which introduces a highly efficient catalyst in the etherification reaction stage to selectively react the etherification reaction raw materials to generate the target etherification product, avoids the complicated post-etherification processing, increases the overall yield of the aromatic diether dianhydride preparation process, and simplifies the overall preparation process.

[0007] This invention is achieved through the following technical solution: A method for preparing an aromatic diether dianhydride includes the following steps: S1. Feeding: Add the dihydroxy monomer, basic compound, transition metal complex catalyst, organic solvent, and dehydrating agent into the reaction vessel, and continuously purge inert gas; S2. Water separation: The water in the reaction system is separated by increasing the temperature; S3. Etherification reaction: Add nitrophthalimide derivative, raise the temperature to carry out etherification reaction, filter after the reaction is completed, remove solvent by vacuum distillation of filtrate to obtain etherified product; S4. The etherified product is subjected to hydrolysis ring-opening, acidification, and dehydration to form a ring, in order to prepare aromatic diether dianhydride.

[0008] Preferably, the dihydroxy monomer is selected from aromatic dihydroxy monomers; the aromatic dihydroxy monomer is selected from any one or more of the following structures: .

[0009] Preferably, the molar ratio of the basic compound to the dihydroxy monomer is (2-2.6):1.

[0010] Preferably, the alkaline compound may be selected from any one or more of potassium benzoate, sodium p-toluenesulfinate, sodium carbonate, anhydrous potassium acetate, potassium carbonate, sodium methoxide, sodium bicarbonate, potassium bicarbonate, sodium formate, potassium acetate, tetrabutyldifluorotriphenylsilicate, potassium tert-butoxide, potassium fluoride, potassium trifluoroacetate, cesium fluoride, sodium acetate, sodium hydroxide, potassium hydroxide, potassium tert-valerate, and sodium nitrite; more preferably, it may be any one or more of anhydrous potassium acetate, potassium carbonate, potassium bicarbonate, sodium methoxide, potassium tert-butoxide, sodium bicarbonate, and sodium carbonate.

[0011] This invention has discovered that by introducing a transition metal complex catalyst, a basic compound promotes the reaction of the hydroxyl groups of the monomer into an organic salt active intermediate. This active intermediate coordinates with the transition metal complex catalyst before reacting, enabling the etherification reaction feedstock to selectively react to generate the target etherified product. This avoids the oxidation and ring-opening of the feedstock and coupling side reactions, significantly improving the yield and purity of the target etherified product and eliminating the need for complex post-etherification processing.

[0012] Preferably, the molar ratio of the transition metal complex catalyst to the dihydroxy monomer is (0.01-0.1):1.

[0013] Preferably, the transition metal complex catalyst is selected from any one or more of ruthenium metal complex catalysts, palladium metal complex catalysts, and titanium metal complex catalysts. More preferably, the transition metal complex catalyst is selected from ruthenium metal complex catalysts.

[0014] The preferred ruthenium metal complex catalyst is any one or more of the following: tris(triphenylphosphine)ruthenium dichloride, dodecacarbonyltriruthenium, dichlorobis(4-methylisopropylphenyl)ruthenium, tris(triphenylphosphine)carbonyl ruthenium hydrochloride, tris(triphenylphosphine)carbonyl dihydroruthenium, trichlorotris(triphenylphosphine)ruthenium(II) toluene adduct, hexaammonium trichloride, bis(tricyclohexylphosphine)carbonyl ruthenium hydrochloride, tris(2,2'-bipyridine)ruthenium dichloride, tris(2,2'-bipyridine)ruthenium dichloride hexahydrate, cyclooctadiene ruthenium dichloride, and ruthenium trichloride hydrate.

[0015] The palladium metal complex catalyst is preferably any one or more of palladium on carbon, palladium acetate, palladium chloride, and [1,1-bis(diphenylphosphino)ferrocene]palladium dichloride; The titanium metal complex catalyst is preferably any one or more of bis(pentamethylcyclopentene)titanium chloride and tetrabutyl titanate.

[0016] Preferably, the organic solvent is selected from any one or more of N,N-dimethylformamide (DMF), N,N-dimethylacetamide (DMAc), N-methylpyrrolidone (NMP), dimethyl sulfoxide (DMSO), sulfolane, and ethylene glycol.

[0017] Preferably, the molar ratio of the water-separating agent to the dihydroxy monomer is (1.5-2.0):1.

[0018] Preferably, the dehydrating agent is selected from any one or more of toluene, xylene, chlorobenzene, dichloroethane, carbon tetrachloride, chloroform, cyclohexane, diethyl ether, ethyl acetate, and benzene.

[0019] After the feed is introduced in step S1, an inert gas is continuously introduced to purge the air from the reaction system. Preferably, the inert gas is selected from nitrogen, carbon dioxide, argon, or helium.

[0020] Preferably, the solid content of the reaction system in step S1 is 25-50%.

[0021] Before the etherification reaction, the water in the reaction system must be separated. Preferably, the water separation temperature in step S2 is 90℃-140℃, and the water separation time is 1h-7h.

[0022] Preferably, the amount of nitrophthalimide derivative used in step S3 is: the molar ratio of nitrophthalimide derivative to dihydroxy monomer is (2-2.05):1.

[0023] The nitrophthalimide derivative is preferably N-substituted-4-nitrophthalimide or N-substituted-3-nitrophthalimide.

[0024] The N-substituted-4-nitrophthalimide is selected from any one of the structures of Formula I; the N-substituted-3-nitrophthalimide is selected from any one of the structures of Formula II; Formula I; Formula II; In Equations I and II, R is -C n H 2n+1 or Any one of the following, where n=0-6, m=0-3, and * indicates the replacement position.

[0025] Preferably, the etherification reaction temperature in step S3 is 120℃-170℃, and the reaction time is 2h-6h.

[0026] Preferably, after the etherification reaction in step S3 is completed, the product is filtered while hot, and the filtrate is collected and the solvent is removed by vacuum distillation at 130-140℃ to obtain a molten product. After cooling, the target etherified product is collected. The filter residue is recovered, washed with water and dried to obtain a clean catalyst that can be recycled for the next etherification reaction.

[0027] In this invention, the hydrolysis ring-opening, acidification, and dehydration cyclization reactions in step S4 can all be carried out using known conventional methods to prepare aromatic diether dianhydrides.

[0028] This invention provides a method for obtaining aromatic diether dianhydride by hydrolysis, ring-opening, acidification, and dehydration of an etherified product, comprising the following steps: placing the etherified product in a high-pressure reactor, adding an aqueous sodium hydroxide solution, and reacting at 140-160°C for 3-5 hours under high pressure to obtain a ring-opening product, followed by acidification with a 50-70% hydrochloric acid solution, filtration, and then heating the filter residue to 190-210°C and stirring for dehydration for 2-5 hours to prepare the aromatic diether dianhydride; preferably, the mass concentration of the aqueous sodium hydroxide solution is 40%-65%; and the reaction pressure is 0.4-1.2 MPa.

[0029] Compared with the prior art, the present invention has the following beneficial effects: The method for preparing aromatic diether dianhydrides of the present invention introduces a specific catalyst in the etherification reaction stage to form a highly selective catalytic system, which can effectively suppress the generation of by-products, significantly improve the yield and purity of the target etherified product, and can be applied to subsequent reactions without further purification treatment. This avoids the cumbersome steps of etherification purification, simplifies the overall preparation process, reduces the preparation cost of aromatic diether dianhydrides, and is suitable for industrial production. Attached Figure Description

[0030] Figure 1 The liquid chromatogram of the etherified product obtained in Example 1; Figure 2The liquid chromatogram of BPADA prepared in Example 1; Figure 3 The 1H NMR spectrum of BPADA obtained in Example 1; Figure 4 The liquid chromatogram of the etherified product obtained in Comparative Example 1 is shown. Figure 5 The image shows the liquid chromatogram of the etherified product obtained in Comparative Example 2. Detailed Implementation

[0031] The present invention will be described in detail below with reference to specific embodiments. These embodiments will help those skilled in the art to further understand the present invention, but do not limit the invention in any way. It should be noted that those skilled in the art can make several modifications and improvements without departing from the concept of the present invention, and these all fall within the scope of protection of the present invention. It should be noted that any processes not specifically described in detail below are those that can be implemented or understood by those skilled in the art with reference to existing technology. Reagents or instruments whose manufacturers are not specified are considered to be conventional products that can be purchased commercially.

[0032] The reagents used in the embodiments and comparative examples of this invention are all commercially available, but are not limited to these materials.

[0033] Product purity was tested using liquid chromatography. Instrument: Wufeng liquid chromatograph; Column: Arcus EP-C18 5μm; Flow rate: 1 mL / min; Detection wavelength: 254nm; Mobile phase: 90% methanol solution. Example 1

[0034] 1141.4 g (5 mol) of bisphenol A, 567.2 g (2.1 equivalents) of sodium methoxide, 95.14 g (0.1 mol) of tris(triphenylphosphine)carbonyl ruthenium hydrochloride, 1 L of xylene, and 6171.6 g of N,N-dimethylformamide (DMF) were added to a reaction flask equipped with a mechanical stirrer, condenser, and water separator. Nitrogen gas was continuously introduced, and the solid content of the reaction system was 34%. The temperature was raised to 130 °C and water was separated for 3 hours. After water separation, 2061.5 g (2 equivalents) of 4-nitro-N-methylphthalimide was added, and the temperature was raised to 150 °C and reacted for 5 hours. After the reaction, the mixture was hot-filtered, and the filtrate was distilled under reduced pressure at 130 °C to remove the solvent, yielding 2727.4 g of etherified product solid, with an etherification yield of 99.8% and a purity of 99.9% as determined by liquid chromatography. The filter residue was washed with water and dried to obtain a clean catalyst, which was recycled for the next etherification reaction.

[0035] The etherified product was placed in an autoclave and reacted at 1.2 MPa and 160°C for 3 hours using 4 equivalents of 50% sodium hydroxide aqueous solution (1600 g) to obtain the ring-opening product. The product was then acidified with 4 equivalents of 70% hydrochloric acid solution (1042.9 g), filtered, and the filter residue was heated to 190°C and stirred for 2 hours to dehydrate, yielding 2573.8 g of bisphenol A diether dianhydride (BPADA) solid, with a yield of 98.9%. Example 2

[0036] 1141.4 g (5 mol) of bisphenol A, 567.2 g (2.1 equivalents) of sodium methoxide, 95.14 g (0.1 mol) of tris(triphenylphosphine)carbonyl ruthenium hydrochloride catalyst (recycled 12 times), 1 L of xylene, and 6176.6 g of N,N-dimethylformamide (DMF) were added to a reaction flask equipped with a mechanical stirrer, condenser, and water separator. Nitrogen gas was continuously introduced, and the solid content of the reaction system was 34%. The temperature was raised to 130 °C and water was separated for 3 hours. After water separation, 2061.5 g (2 equivalents) of 4-nitro-N-methylphthalimide was added, and the temperature was raised to 150 °C and reacted for 5 hours. After the reaction, the mixture was hot-filtered, and the solvent was removed by vacuum distillation at 130 °C to obtain 2705.6 g of etherified product solid, with an etherification yield of 99.0% and a purity of 98.3% as determined by liquid chromatography.

[0037] The etherified product was placed in an autoclave and reacted at 1.2 MPa and 160°C for 3 hours using 4 equivalents of 50% sodium hydroxide aqueous solution (1600 g) to obtain the ring-opening product. The product was then acidified with 4 equivalents of 70% hydrochloric acid solution (1042.9 g). After filtration, the filter residue was heated to 190°C and stirred for 2 hours to dehydrate, yielding 2537.4 g of bisphenol A diether dianhydride (BPADA) solid, with a yield of 97.5%. Example 3

[0038] 1001.1 g (5 mol) of 4,4'-dihydroxydiphenylmethane, 567.2 g (2.1 equivalents) of sodium methoxide, 95.14 g (0.1 mol) of tris(triphenylphosphine)carbonyl ruthenium hydrochloride, 1 L of xylene, and 6171.6 g of N,N-dimethylformamide (DMF) were added to a reaction flask equipped with a mechanical stirrer, condenser, and water separator. Nitrogen gas was continuously introduced, and the solid content of the reaction system was 33%. The temperature was raised to 130°C and water was separated for 3 hours. After water separation, 2061.5 g (2 equivalents) of 4-nitro-N-methylphthalimide was added, and the temperature was raised to 150°C and the reaction was carried out for 5 hours. After the reaction, the mixture was hot-filtered, and the filtrate was distilled under reduced pressure at 130°C to remove the solvent, yielding 2575.2 g of etherified product solid, with an etherification yield of 99.4% and a purity of 99.2% as determined by liquid chromatography. The filter residue was washed with water and dried to obtain a clean catalyst, which was recycled for the next etherification reaction.

[0039] The etherified product was placed in an autoclave and reacted at 160°C for 3 hours with 4 equivalents of 50% sodium hydroxide aqueous solution (1600 g) under high pressure to obtain the ring-opening product. Then, it was acidified with 4 equivalents of 70% hydrochloric acid solution (1042.9 g), filtered, and the filter residue was heated to 190°C and stirred to dehydrate for 2 hours to prepare 2435.80 g of bisphenol A diether dianhydride (BPADA) solid, with a preparation yield of 99.0%. Example 4

[0040] 931.1 g (5 mol) of biphenyl hydroquinone, 567.2 g (2.1 equivalents) of sodium methoxide, 95.14 g (0.1 mol) of tris(triphenylphosphine)carbonyl ruthenium hydrochloride, 1 L of xylene, and 6171.6 g of N,N-dimethylformamide (DMF) were added to a reaction flask equipped with a mechanical stirrer, condenser, and water separator. Nitrogen gas was continuously introduced, and the solid content of the reaction system was 33%. The temperature was raised to 130 °C and water was separated for 3 hours. After water separation, 2061.5 g (2 equivalents) of 4-nitro-N-methylphthalimide was added, and the temperature was raised to 150 °C and reacted for 5 hours. After the reaction, the mixture was hot-filtered, and the filtrate was distilled under reduced pressure at 130 °C to remove the solvent, yielding 2500.5 g of etherified product solid, with an etherification yield of 99.2% and a purity of 99.7% as determined by liquid chromatography. The filter residue was washed with water and dried to obtain a clean catalyst, which was recycled for the next etherification reaction.

[0041] The etherified product was placed in an autoclave and reacted at 1.2 MPa and 160°C for 3 hours using 4 equivalents of 50% sodium hydroxide aqueous solution (1600 g) to obtain the ring-opening product. The product was then acidified with 4 equivalents of 70% hydrochloric acid solution (1042.9 g), filtered, and the filter residue was heated to 190°C and stirred for 2 hours to dehydrate, yielding 2356.9 g of bisphenol A diether dianhydride (BPADA) solid, with a yield of 98.6%. Example 5

[0042] 1141.4 g (5 mol) of bisphenol A, 567.2 g (2.1 equivalents) of sodium methoxide, 95.14 g (0.1 mol) of tris(triphenylphosphine)carbonyl ruthenium hydrochloride, 1 L of xylene, and 6171.6 g of N,N-dimethylformamide (DMF) were added to a reaction flask equipped with a mechanical stirrer, condenser, and water separator. Nitrogen gas was continuously introduced, and the solid content of the reaction system was 34%. The temperature was raised to 130 °C and water was separated for 3 hours. After water separation, 2061.5 g (2 equivalents) of 3-nitro-N-methylphthalimide was added, and the temperature was raised to 150 °C and reacted for 5 hours. After the reaction, the mixture was hot-filtered, and the solvent was removed by vacuum distillation at 130 °C to obtain 2703.59 g of etherified product solid, with an etherification yield of 99.0% and a purity of 99.8% as determined by liquid chromatography (test results are shown in the figure). Figure 1 (As shown). The filter residue was washed with water and dried to obtain a clean catalyst, which was then recycled for the next etherification reaction.

[0043] The etherified product was placed in an autoclave and reacted at 1.2 MPa and 160°C for 3 hours using 4 equivalents of 50% sodium hydroxide aqueous solution (1600 g) to obtain the ring-opening product. The product was then acidified with 4 equivalents of 70% hydrochloric acid solution (1042.9 g), filtered, and the filter residue was heated to 190°C and stirred for 2 hours to dehydrate, yielding 2551.19 g of bisphenol A diether dianhydride (BPADA) solid, with a yield of 98.1%. Example 6

[0044] 1141.4 g (5 mol) of bisphenol A, 567.2 g (2.1 equivalents) of sodium methoxide, 228.98 g (0.25 mol) of tris(triphenylphosphine)carbonyl dihydroruthenium(II), 1 L of xylene, and 6171.6 g of N,N-dimethylformamide (DMF) were added to a reaction flask equipped with a mechanical stirrer, condenser, and water separator. Nitrogen gas was continuously introduced, and the solid content of the reaction system was 34%. The temperature was raised to 130 °C and water was separated for 3 hours. After water separation, 2061.5 g (2 equivalents) of 4-nitro-N-methylphthalimide was added, and the temperature was raised to 150 °C and reacted for 5 hours. After the reaction, the mixture was hot-filtered, and the filtrate was distilled under reduced pressure at 130 °C to remove the solvent, yielding 2679.01 g of etherified product solid, with an etherification yield of 98.1% and a purity of 99.2% as determined by liquid chromatography (test results are shown in the figure). Figure 1 (As shown). The filter residue was washed with water and dried to obtain a clean catalyst, which was then recycled for the next etherification reaction.

[0045] The etherified product was placed in an autoclave and reacted at 1.2 MPa and 160°C for 3 hours using 4 equivalents of 50% sodium hydroxide aqueous solution (1600 g) to obtain the ring-opening product. The product was then acidified with 4 equivalents of 70% hydrochloric acid solution (1042.9 g), filtered, and the filter residue was heated to 190°C and stirred for 2 hours to dehydrate, yielding 2527.78 g of bisphenol A diether dianhydride (BPADA) solid, with a yield of 97.2%. Example 7

[0046] 1141.4 g (5 mol) of bisphenol A, 567.2 g (2.1 equivalents) of sodium methoxide, 127.87 g (0.2 mol) of dodecacarbonyltriruthenium, 1 L of xylene, and 6171.6 g of N,N-dimethylformamide (DMF) were added to a reaction flask equipped with a mechanical stirrer, condenser, and water separator. Nitrogen gas was continuously introduced, and the solid content of the reaction system was 34%. The temperature was raised to 130 °C and water was separated for 3 hours. After water separation, 2061.5 g (2 equivalents) of 4-nitro-N-methylphthalimide was added, and the temperature was raised to 150 °C and reacted for 5 hours. After the reaction, the mixture was hot-filtered, and the solvent was removed by vacuum distillation at 130 °C to obtain 2703.59 g of etherified product solid, with an etherification yield of 99.0% and a purity of 98.9% as determined by liquid chromatography (test results are shown in the figure). Figure 1(As shown). The filter residue was washed with water and dried to obtain a clean catalyst, which was then recycled for the next etherification reaction.

[0047] The etherified product was placed in an autoclave and reacted at 1.2 MPa and 160°C for 3 hours using 4 equivalents of 50% sodium hydroxide aqueous solution (1600 g) to obtain the ring-opening product. The product was then acidified with 4 equivalents of 70% hydrochloric acid solution (1042.9 g), filtered, and the filter residue was heated to 190°C and stirred for 2 hours to dehydrate, yielding 2553.79 g of bisphenol A diether dianhydride (BPADA) solid, with a yield of 98.2%. Example 8

[0048] 1141.4 g (5 mol) of bisphenol A, 1178.2 g (2.1 equivalents) of potassium tert-butoxide, 95.14 g (0.1 mol) of tris(triphenylphosphine)carbonyl ruthenium hydrochloride, 1 L of xylene, and 6171.6 g of N,N-dimethylformamide (DMF) were added to a reaction flask equipped with a mechanical stirrer, condenser, and water separator. Nitrogen gas was continuously introduced, and the solid content of the reaction system was 34%. The temperature was raised to 130 °C and water was separated for 3 hours. After water separation, 2061.5 g (2 equivalents) of 4-nitro-N-methylphthalimide was added, and the temperature was raised to 150 °C and reacted for 5 hours. After the reaction, the mixture was hot-filtered, and the solvent was removed by vacuum distillation at 130 °C to obtain 2703.6 g of etherified product solid, with an etherification yield of 99.0% and a purity of 99.5% as determined by liquid chromatography (test results are shown in the figure). Figure 1 (As shown). The filter residue was washed with water and dried to obtain a clean catalyst, which was then recycled for the next etherification reaction.

[0049] The etherified product was placed in an autoclave and reacted at 1.2 MPa and 160°C for 3 hours using 4 equivalents of 50% sodium hydroxide aqueous solution (1600 g) to obtain the ring-opening product. The product was then acidified with 4 equivalents of 70% hydrochloric acid solution (1042.9 g), filtered, and the filter residue was heated to 190°C and stirred for 2 hours to dehydrate, yielding 2553.8 g of bisphenol A diether dianhydride (BPADA) solid, with a yield of 98.2%. Example 9

[0050] 1141.4 g (5 mol) of bisphenol A, 567.2 g (2.1 equivalents) of sodium methoxide, 95.14 g (0.1 mol) of tris(triphenylphosphine)carbonyl ruthenium hydrochloride, 1 L of xylene, and 6171.6 g of N-methylpyrrolidone were added to a reaction flask equipped with a mechanical stirrer, condenser, and water separator. Nitrogen gas was continuously introduced, and the solid content of the reaction system was 34%. The temperature was raised to 130 °C and water was separated for 3 hours. After water separation, 2061.5 g (2 equivalents) of 4-nitro-N-methylphthalimide was added, and the temperature was raised to 150 °C and reacted for 5 hours. After the reaction, the mixture was hot-filtered, and the solvent was removed by vacuum distillation at 130 °C to obtain 2651.7 g of etherified product solid, with an etherification yield of 97.1% and a purity of 99.0% as determined by liquid chromatography (test results are shown in the figure). Figure 1 (As shown). The filter residue was washed with water and dried to obtain a clean catalyst, which was then recycled for the next etherification reaction.

[0051] The etherified product was placed in an autoclave and reacted at 1.2 MPa and 160°C for 3 hours using 4 equivalents of 50% sodium hydroxide aqueous solution (1600 g) to obtain the ring-opening product. The product was then acidified with 4 equivalents of 70% hydrochloric acid solution (1042.9 g), filtered, and the filter residue was heated to 190°C and stirred for 2 hours to dehydrate, yielding 2514.8 g of bisphenol A diether dianhydride (BPADA) solid, with a yield of 96.7%. Example 10

[0052] 1141.4 g (5 mol) of bisphenol A, 567.2 g (2.1 equivalents) of sodium methoxide, 95.14 g (0.1 mol) of tris(triphenylphosphine)carbonyl ruthenium hydrochloride, 1 L of toluene, and 6171.6 g of N,N-dimethylformamide (DMF) were added to a reaction flask equipped with a mechanical stirrer, condenser, and water separator. Nitrogen gas was continuously introduced, and the solid content of the reaction system was 34%. The temperature was raised to 130 °C and water was separated for 3 hours. After water separation, 2061.5 g (2 equivalents) of 4-nitro-N-methylphthalimide was added, and the temperature was raised to 150 °C and reacted for 5 hours. After the reaction, the mixture was hot-filtered, and the solvent was removed by vacuum distillation at 130 °C to obtain 2722.7 g of etherified product solid, with an etherification yield of 99.7% and a purity of 99.5% as determined by liquid chromatography (test results are shown in the figure). Figure 1 (As shown). The filter residue was washed with water and dried to obtain a clean catalyst, which was then recycled for the next etherification reaction.

[0053] The etherified product was placed in an autoclave and reacted at 1.2 MPa and 160°C for 3 hours using 4 equivalents of 50% sodium hydroxide aqueous solution (1600 g) to obtain the ring-opening product. The product was then acidified with 4 equivalents of 70% hydrochloric acid solution (1042.9 g), filtered, and the filter residue was heated to 190°C and stirred for 2 hours to dehydrate, yielding 2569.4 g of bisphenol A diether dianhydride (BPADA) solid, with a yield of 98.8%.

[0054] Comparative Example 1 1141.4 g (5 mol) of bisphenol A, 567.2 g (2.1 equivalents) of sodium methoxide, 1 L of xylene, and 6171.6 g (34% solid content) of N,N-dimethylformamide (DMF) were added to a reaction flask equipped with a mechanical stirrer, condenser, and water separator. The mixture was heated to 130 °C and water was separated for 3 hours. After water separation, 2061.5 g (2 equivalents) of 4-nitro-N-methylphthalimide was added, and the mixture was heated to 150 °C and reacted for 5 hours. After the reaction, the mixture was hot-filtered, and the solvent was removed by vacuum distillation at 130 °C to obtain 2135.6 g of etherified product solid, with an etherification yield of 78.2%. Liquid chromatography analysis showed that the purity of the target product was 48.8%, byproduct A was 15.1%, and byproduct B was 4.5%.

[0055] The etherified product was placed in an autoclave and reacted at 1.2 MPa and 160°C for 3 hours using 4 equivalents of 50% sodium hydroxide aqueous solution to obtain the ring-opening product. After acidification with 4 equivalents of 70% hydrochloric acid solution and filtration, the filter residue was heated to 190°C and stirred for 2 hours to dehydrate, yielding 1626.5 g of bisphenol A diether dianhydride (BPADA) solid, with a yield of 62.5%.

[0056] Comparative Example 2 1141.46 g (5 mol) of bisphenol A, 567.21 g (2.1 equivalents) of sodium methoxide, 181.63 g (0.1 mol) of copper acetate, 1 L of xylene, and 6171.6 g (34% solid content) of N,N-dimethylformamide (DMF) were added to a reaction flask equipped with a mechanical stirrer, condenser, and water separator. The mixture was heated to 130 °C and water was separated for 3 hours. After water separation, 2061.5 g (2 equivalents) of 4-nitro-N-methylphthalimide was added, and the mixture was heated to 150 °C and reacted for 5 hours. After the reaction, the mixture was hot-filtered, and the solvent was removed by vacuum distillation at 130 °C, yielding 2184.72 g of etherified solid product with an etherification yield of 80.0%. Liquid chromatography analysis showed that the purity of the target product was 78.6%, byproduct A was 4.0%, and byproduct B was 7.1% (test results are shown in the figure). Figure 5 (As shown).

[0057] The etherified product was placed in an autoclave and reacted at 1.2 MPa and 160°C for 3 hours using 4 equivalents of 50% sodium hydroxide aqueous solution to obtain the ring-opening product. After acidification with 4 equivalents of 70% hydrochloric acid solution and filtration, the filter residue was heated to 190°C and stirred for 2 hours to dehydrate, yielding 1651.38 g of bisphenol A diether dianhydride (BPADA) solid, with a yield of 63.5%.

[0058] As can be seen from the above embodiments, the method for preparing aromatic diether dianhydrides of the present invention, by introducing a transition metal complex catalyst in the etherification reaction stage to form a highly selective catalytic system, can effectively suppress the generation of by-products, significantly improve the yield and purity of the target etherified product, avoid the cumbersome steps of etherification purification, simplify the overall preparation process, and is suitable for industrial production.

[0059] In Comparative Example 1, the transition metal complex catalyst described in this invention was not added during the etherification reaction stage, and the yield of the target etherified product was only 78.2%, with a purity of 48.8%. The product was directly used for the subsequent preparation of BPADA without purification, resulting in a low yield of the target product.

[0060] In Comparative Example 2, copper acetate was added as a catalyst in the etherification reaction stage, and the yield of the target etherified product was only 80.0%, with a purity of 78.6%. The product was directly used in the subsequent preparation of BPADA without purification, resulting in a low yield of the target product.

Claims

1. A method for preparing an aromatic diether dianhydride, characterized by, The method comprises the following steps: S1. Feeding: adding a dihydroxy monomer, a basic compound, a transition metal complex catalyst, an organic solvent, and a water-removing agent into a reaction container, and continuously feeding inert gas; S2. Water removal: separating water in the reaction system by increasing temperature; S3. Etherification reaction: adding a nitrophthalimide derivative, and increasing temperature to perform etherification reaction; after the reaction is completed, filtering, and removing the solvent from the filtrate by reduced pressure distillation to obtain an etherification product; S4. The etherification product is subjected to hydrolysis ring-opening, acidification, and dehydration to form a ring to obtain an aromatic diether dianhydride.

2. The method of claim 1, wherein the aromatic diether dianhydride is prepared by the reaction of the aromatic diether diol with a dehydrating agent. The molar ratio of the basic compound to the dihydroxy monomer is (2-2.6):1; the molar ratio of the transition metal complex catalyst to the dihydroxy monomer is (0.01-0.1):1; the molar ratio of the water-removing agent to the dihydroxy monomer is (1.5-2.0):1; and the molar ratio of the nitrophthalimide derivative to the dihydroxy monomer is (2-2.05):

1.

3. The method of claim 1, wherein the aromatic diether dianhydride is prepared by the reaction of the aromatic diether diacid with acetic anhydride. The solid content of the reaction system in step S1 is 25-50%.

4. The method of claim 1, wherein the aromatic diether dianhydride is prepared by the reaction of the aromatic diether diacid with acetic anhydride. The water removal temperature in step S2 is 90-140°C, and the water removal time is 1-7h.

5. The method of claim 1, wherein the aromatic diether dianhydride is prepared by the reaction of the aromatic diether diacid with acetic anhydride. The etherification reaction temperature in step S3 is 120-170°C, and the reaction time is 2-6h.

6. The method of claim 1, wherein the aromatic diether dianhydride is prepared by the reaction of a diol and a diacid chloride. The dihydroxy monomer is selected from aromatic dihydroxy monomers; the aromatic dihydroxy monomer is selected from any one or more of the following structures: 。 7. The method of claim 1, wherein the aromatic diether dianhydride is prepared by the reaction of a diol and a diacid chloride in the presence of a base. The basic compound is selected from any one or more of potassium benzoate, sodium p-toluenesulfinate, sodium carbonate, anhydrous potassium acetate, potassium carbonate, sodium methoxide, sodium bicarbonate, potassium bicarbonate, sodium formate, potassium acetate, tetrabutylammonium difluorotriphenylsilicate, potassium tert-butoxide, potassium fluoride, potassium trifluoroacetate, cesium fluoride, sodium acetate, sodium hydroxide, potassium hydroxide, potassium pivalate, and sodium nitrite, preferably any one or more of anhydrous potassium acetate, potassium carbonate, potassium bicarbonate, sodium methoxide, potassium tert-butoxide, sodium bicarbonate, and sodium carbonate.

8. The method for preparing aromatic diether dianhydride according to claim 1, characterized in that, The transition metal complex catalyst is selected from any one or more of a ruthenium metal complex catalyst, a palladium metal complex catalyst, and a titanium metal complex catalyst; the ruthenium metal complex catalyst is selected from any one or more of tris(triphenylphosphine)ruthenium dichloride, triruthenium dodecacarbonyl, dichlorobis(4-methylisopropylphenyl)ruthenium, tris(triphenylphosphine)carbonylhydridoruthenium, tris(triphenylphosphine)carbonyldihydridoruthenium, chlorohydridotris(triphenylphosphine)ruthenium(II)toluene adduct, hexaammoniumruthenium dichloride, dichlorobis(tricyclohexylphosphine)carbonylhydridoruthenium, tris(2,2'-bipyridyl)ruthenium dichloride, tris(2,2'-bipyridyl)ruthenium dichloride hexahydrate, and cyclooctadiene ruthenium dichloride; the palladium metal complex catalyst is selected from any one or more of palladium on carbon, palladium acetate, palladium chloride, and [1,1-bis(diphenylphosphino)ferrocene]palladium dichloride; the titanium metal complex catalyst is selected from any one or more of bis(pentamethylcyclopentadienyl)titanium dichloride and tetrabutyl titanate; preferably, the transition metal complex catalyst is selected from a ruthenium metal complex catalyst.

9. The method for preparing aromatic diether dianhydride according to claim 1, characterized in that, The organic solvent is selected from any one or more of N,N-dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidone, dimethyl sulfoxide, sulfolane, ethylene glycol; the water-removing agent is selected from any one or more of toluene, xylene, chlorobenzene, dichloroethane, carbon tetrachloride, chloroform, cyclohexane, diethyl ether, ethyl acetate, benzene; the inert gas is selected from nitrogen, carbon dioxide, argon or helium.

10. The method for preparing aromatic diether dianhydrides according to claim 1, characterized in that, The nitrophthalimide derivative is selected from N-substituted-4-nitrophthalimide or N-substituted-3-nitrophthalimide; the N-substituted-4-nitrophthalimide is selected from any one of the structures in formula I; the N-substituted-3-nitrophthalimide is selected from any one of the structures in formula II; Formula I; Formula II; R in formula I, formula II is -C n H 2n+1 or any of the following: wherein n = 0-6, m = 0-3, * indicates a position of substitution.

Images