Preparation method of p-phenylene-bis-benzene trimellitate dianhydride
By using catalysts such as pyridine and N,N-diisopropylethylamine combined with acetic anhydride purification, the problems of low purity and high cost in the synthesis of p-phenylene-bisphenyltrimethuronic acid dianhydride were solved, achieving the preparation of high-purity and high-yield products suitable for industrial applications.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- 安徽拉瓦锡科技有限公司
- Filing Date
- 2025-12-19
- Publication Date
- 2026-05-01
AI Technical Summary
The existing synthesis process of p-phenylene-bisphenyltriester dianhydride has problems such as expensive catalysts, difficult purification, low product purity, low whiteness and complex process, which makes it difficult to apply on a large scale.
Pyridine and N,N-diisopropylethylamine were used as catalysts, and acetic anhydride was used to purify the crude p-phenylene-bisphenyltriptate dianhydride. The purity and whiteness were improved by recrystallization and reaction with acetic anhydride.
It achieves high purity (over 99.5%) and high yield (over 80%) of p-phenylene bisphenyltriester dianhydride, reducing production costs, simplifying the process, and making it suitable for industrial production.
Smart Images
Figure FT_1 
Figure FT_2 
Figure FT_3
Abstract
Description
A method for preparing p-phenylene-bisphenyltriester dianhydride Technical Field
[0001] This invention relates to the field of organic compound preparation technology, and in particular to a method for preparing p-phenylene-bisphenyltriester dianhydride. Background Technology
[0002] Polyimide, as a high-temperature resistant polymer material, has been widely used in flexible displays, aerospace thermal insulation, chip packaging, fuel cells, high-temperature filtration, and the nuclear industry. Whether used as a high-temperature structural material or a functional membrane material, its application prospects have been highly recognized by the industry. However, polyimide itself has inherent problems such as difficult molding and processing, a high coefficient of thermal expansion, strong hygroscopicity, and a relatively high dielectric constant, which to some extent limit its application expansion in certain scenarios.
[0003] Polyesterimide is a modified polyimide resin whose molecular backbone contains both ester groups and imine rings. The introduction of ester bonds improves the molding and processability of polyimide materials, enhances their strength and modulus, and reduces their coefficient of thermal expansion, hygroscopicity, and dielectric constant, thus enabling them to be used more widely in the electronics field.
[0004] p-Phenylidene-bisphenyltrilate dianhydride is an important monomer for the synthesis of polyester imides. The commonly used synthetic routes for p-Phenylidene-bisphenyltrilate dianhydride are as follows: .
[0005] In this synthesis process, in addition to the main product, p-phenylene bisphenyltriester dianhydride, a third product was also generated. , Multiple byproducts are also produced. This is because the raw materials for the synthesis of p-phenylene-bisphenyltrilate dianhydride contain acid anhydrides and acyl chlorides with similar activities, making the synthesis difficult to control, resulting in purification difficulties and low product purity. Furthermore, current methods for preparing p-phenylene-bisphenyltrilate dianhydride also suffer from low product whiteness, complex processes, and high costs. For example, existing technologies disclose a method for synthesizing p-phenylene-bisphenyltrilate dianhydride using hydroquinone and chlorinated trimellitic anhydride as reactants, with the catalyst prepared from formaldehyde, dialkylamine, and ion exchange resin. In this method, the ion exchange resin is expensive, leading to high process costs and making large-scale application difficult. Additionally, the catalyst recovery process is complex. Summary of the Invention
[0006] The present invention aims to at least solve one of the aforementioned technical problems existing in the prior art. Therefore, the object of the present invention is to provide a method for preparing p-phenylene-bisphenyltrilate dianhydride, by selecting a suitable catalyst and using acetic anhydride to purify the crude p-phenylene-bisphenyltrilate dianhydride, thereby improving the purity and whiteness of the p-phenylene-bisphenyltrilate dianhydride.
[0007] To achieve the above objectives, the technical solution adopted by the present invention is as follows: The first aspect of the present invention provides a method for preparing p-phenylene-bisphenyltrilate dianhydride, comprising the following steps: mixing trimellitic anhydride chloride, hydroquinone, and a catalyst to react and obtain crude p-phenylene-bisphenyltrilate dianhydride; recrystallizing the crude p-phenylene-bisphenyltrilate dianhydride and mixing it with acetic anhydride to react and obtain the p-phenylene-bisphenyltrilate dianhydride; the catalyst comprises at least one selected from pyridine, triethylamine, N,N-diisopropylethylamine, diethylamine, and dimethylamine.
[0008] Preferably, the catalyst comprises pyridine and N,N-diisopropylethylamine.
[0009] More preferably, in the catalyst, the molar ratio of pyridine to N,N-diisopropylethylamine is 1:(1~3).
[0010] More preferably, in the catalyst, the molar ratio of pyridine to N,N-diisopropylethylamine is 1:(1.5~2.5).
[0011] Preferably, the molar ratio of hydroquinone, trimellitic anhydride chloride and the catalyst is 1:(2~5):(2~5).
[0012] More preferably, the molar ratio of hydroquinone, trimellitic anhydride chloride and the catalyst is 1:(2~3):(2~4).
[0013] Preferably, the recrystallized crude p-phenylene bisphenyltriester dianhydride has a mass ratio of 1:(1~4) to the acetic anhydride.
[0014] More preferably, the recrystallized crude p-phenylene bisphenyltriester dianhydride has a mass ratio of 1:(1~3) to the acetic anhydride.
[0015] More preferably, the recrystallized crude p-phenylene bisphenyltriester dianhydride has a mass ratio of 1:(1.5~2.5) to the acetic anhydride.
[0016] Preferably, the preparation method includes the following steps: mixing trimellitic anhydride chloride with a first solvent to form a homogeneous solution, obtaining a bottom liquid phase; mixing hydroquinone and a catalyst with the first solvent to form a homogeneous solution, obtaining a dropwise phase; adding the dropwise phase dropwise to the bottom liquid phase to carry out a first reaction; after the first reaction is completed, performing solid-liquid separation to obtain a crude p-phenylene-bisphenyltriptyl dianhydride; redissolving and crystallizing the crude p-phenylene-bisphenyltriptyl dianhydride to obtain a recrystallized crude product; mixing the recrystallized crude product with acetic anhydride to carry out a second reaction to obtain the p-phenylene-bisphenyltriptyl dianhydride.
[0017] More preferably, the temperature of the first reaction is ≤35°C.
[0018] More preferably, the first reaction process includes the following steps: starting the dropwise addition of the additive phase to the bottom liquid phase at room temperature to carry out the first reaction, and controlling the temperature in the first reaction process to be ≤35℃; or, cooling down to below 20℃, adding the additive phase to the bottom liquid phase to carry out the first reaction.
[0019] More preferably, the reaction time of the first reaction is 6 to 10 hours.
[0020] It should be understood that the reaction occurs while the dropwise phase is being added dropwise to the bottom liquid phase. Therefore, the time of the first reaction includes the time of dropwise addition and the time of heat preservation. After the dropwise addition is completed, the temperature is maintained for 1 to 3 hours.
[0021] More preferably, the temperature of the second reaction is 80~120°C.
[0022] More preferably, the temperature of the second reaction is 90~110°C.
[0023] More preferably, the second reaction takes 7 to 9 hours.
[0024] More preferably, after the solid-liquid separation, the obtained solid is washed and dried with a second solvent to obtain crude p-phenylene-bisphenyltriterpenoid dianhydride.
[0025] More preferably, the resolution and crystallization include the following steps: adding the crude p-phenylene-bisphenyltrilate dianhydride to a third solvent, heating to 30-70°C and holding for 1-5 hours, then cooling to below 10°C, and separating the solid and liquid to obtain the recrystallized crude product; or, adding the crude p-phenylene-bisphenyltrilate dianhydride to a third solvent, cooling to below 10°C and holding for 2-6 hours, and separating the solid and liquid to obtain the recrystallized crude product.
[0026] More preferably, the first solvent includes at least one of dichloromethane and acetonitrile.
[0027] More preferably, the second solvent includes at least one of tetrahydrofuran, toluene, acetonitrile, ethyl acetate, and N,N-dimethylacetamide.
[0028] More preferably, the third solvent includes at least one of water, chloroform, dichloromethane, acetone, and N,N-dimethylacetamide.
[0029] More preferably, the second reaction includes the following steps: mixing the recrystallized crude product with acetic anhydride, heating to 80~120°C to carry out the second reaction; after the second reaction is completed, cooling to below 10°C to carry out solid-liquid separation to obtain the p-phenylene-bisphenyltriester dianhydride.
[0030] More preferably, the solid-liquid separation process further includes a drying step.
[0031] Compared with existing technologies, the beneficial effects of this invention are as follows: This invention provides a method for preparing p-phenylene-bisphenyltrilate dianhydride. By selecting a suitable catalyst and using acetic anhydride to purify the crude p-phenylene-bisphenyltrilate dianhydride, the purity and whiteness of the p-phenylene-bisphenyltrilate dianhydride are improved. This preparation method has advantages such as short reaction steps, mild conditions, simple post-processing, high yield, simple purification steps, and high product purity. The yield of the p-phenylene-bisphenyltrilate dianhydride product synthesized by this method can reach 80%, while the purity can reach over 99.5%, the metal ion content is less than 500 ppb, the total chlorine is less than 5 ppm, and the yellowness is less than 2, making it suitable for industrial production. Attached Figure Description
[0032] Figure 1 is the 1H NMR spectrum of the p-phenylene-bisphenyltriester dianhydride prepared in Example 1 of this invention.
[0033] Figure 2 is a high-performance liquid chromatogram of the p-phenylene-bisphenyltriester dianhydride prepared in Example 1 of the present invention.
[0034] Figure 3 is a differential scanning calorimeter of the p-phenylene-bisphenyltriester dianhydride prepared in Example 1 of the present invention. Detailed Implementation
[0035] The present invention will be further described in detail below through specific embodiments. Unless otherwise specified, the raw materials, reagents, or apparatus used in the embodiments and comparative examples are all available from conventional commercial sources or can be obtained by existing technical methods. Unless otherwise specified, the test or experimental methods are conventional methods in the art.
[0036] The following detailed description is provided in conjunction with specific embodiments and comparative examples.
[0037] In the following examples and comparative examples, yellowness was detected by a whiteness meter, metal ions were detected by ICP-MS (inductively coupled plasma mass spectrometry), total chlorine was detected by CIC (ion chromatography), and purity was detected by HPLC (high performance liquid chromatography).
[0038] Example 1: A method for preparing p-phenylene-bis(phenyltripterygium ester) dianhydride, comprising the following steps: Under nitrogen protection, 165.1 g (0.784 mol) of trimellitic anhydride chloride dissolved in 600 g of dichloromethane is added to a reaction flask as the bottom liquid phase; 40 g (0.363 mol) of hydroquinone, 93.8 g (0.726 mol) of N,N-diisopropylethylamine, and 28.7 g (0.363 mmol) of pyridine are dissolved in 600 g of dichloromethane as the dropping phase; the bottom liquid phase is cooled to between 10 and 20 °C, and the temperature inside the reactor is maintained. The dropping phase is then added dropwise to the bottom liquid phase, with the internal reaction temperature ≤ 35 °C. The dropping time is controlled at 6 h, and the temperature is maintained for 2 h after the dropping. After the reaction is complete, the mixture is filtered, and the filter cake is treated with 60 g of dichloromethane solution. 0 g of tetrahydrofuran was washed and dried under vacuum to obtain 195.74 g of crude p-phenylene-bisphenyltrilate dianhydride. 1.5 kg of water was added to a reactor and stirred. The crude p-phenylene-bisphenyltrilate dianhydride was added to the 1.5 kg of water, cooled to 5-10 °C and kept at that temperature for 4 h. After filtration and drying, 166.38 g of crude p-phenylene-bisphenyltrilate dianhydride recrystallized was obtained. This crude p-phenylene-bisphenyltrilate dianhydride was added to 332.76 g of acetic anhydride and refluxed at 100 °C ± 3 °C for 8 h. The resulting reaction solution was cooled to below 10 °C, filtered, and dried under vacuum to obtain 134.9 g of p-phenylene-bisphenyltrilate dianhydride.
[0039] As shown in Figures 1 to 3, p-phenylene-bisphenyltriester dianhydride was successfully prepared in Example 1 of the present invention.
[0040] Upon testing, the p-phenylene-bisphenyltrilate dianhydride obtained in this embodiment was a white powder with a yellowness of less than 2, containing 308.7 ppb of metal ions and 3.27 ppm of total chlorine, with a yield of 81.1% and a content of 99.72%.
[0041] Example 2: A method for preparing p-phenylene-bis(phenyltrilate) dianhydride, comprising the following steps: Under nitrogen protection, 165.1 g (0.784 mol) of trimellitic anhydride chloride dissolved in 600 g of dichloromethane is added to a reaction flask as the bottom liquid phase; 40 g (0.363 mol) of hydroquinone, 93.8 g (0.726 mol) of N,N-diisopropylethylamine, and 28.7 g (0.363 mmol) of pyridine are dissolved in 600 g of dichloromethane as the dropping phase; the dropping phase is added dropwise to the bottom liquid phase at room temperature, the temperature is controlled at 25-35°C, the dropping time is controlled at 6 h, and the temperature is maintained for 2 h after the addition. After the reaction is complete, the mixture is filtered, the filter cake is washed with 600 g of tetrahydrofuran, and then vacuum dried. 193.1 g of crude p-phenylene-bisphenyltriptyl dianhydride was obtained by drying. 1.5 kg of water was added to a reactor and stirring was started. The crude p-phenylene-bisphenyltriptyl dianhydride was added to the 1.5 kg of water, and the mixture was heated to 60 °C and held for 4 h. The resulting reaction solution was cooled to below 10 °C, filtered, and dried to obtain 177.4 g of crude p-phenylene-bisphenyltriptyl dianhydride by recrystallization. 177.4 g of crude p-phenylene-bisphenyltriptyl dianhydride by recrystallization was added to 361.8 g of acetic anhydride, and the mixture was refluxed at 100 °C ± 3 °C for 8 h. The resulting reaction solution was cooled to below 10 °C, filtered, and vacuum dried to obtain 132.5 g of p-phenylene-bisphenyltriptyl dianhydride.
[0042] Upon testing, the p-phenylene-bisphenyltrilate dianhydride obtained in this embodiment was a white powder with a yellowness of less than 1, containing 274.95 ppb of metal ions, a total chlorine yield of 3.62 ppm, a yield of 79.8%, and a content of 99.53%.
[0043] Example 3: A method for preparing p-phenylene-bis(phenyltripterygium ester) dianhydride, comprising the following steps: Under nitrogen protection, 165.1 g (0.784 mol) of trimellitic anhydride chloride dissolved in 600 g of acetonitrile was added to a reaction flask as the bottom liquid phase; 40 g (0.363 mol) of hydroquinone, 93.8 g (0.726 mol) of N,N-diisopropylethylamine, and 28.7 g (0.363 mmol) of pyridine were dissolved in 600 g of acetonitrile as the dropping phase; the dropping phase was added dropwise to the bottom liquid phase at room temperature, the reaction temperature was controlled between 25 and 35 °C, the dropping time was controlled at 6 h, and the temperature was maintained for 2 h after the dropping was completed. After the reaction was complete, the mixture was filtered, the filter cake was washed with 600 g of tetrahydrofuran, and dried under vacuum to obtain the desired product. 197.07 g of crude p-phenylene-bisphenyltriptyl dianhydride was obtained. 1.5 kg of water was added to a reactor and stirring was started. The mixture was heated to 40 ± 2 °C and kept at that temperature for 4 h. The resulting reaction solution was cooled to below 10 °C, filtered, and dried to obtain 175.4 g of crude p-phenylene-bisphenyltriptyl dianhydride recrystallized from acetic anhydride. This 175.4 g of crude p-phenylene-bisphenyltriptyl dianhydride recrystallized from acetic anhydride was added to 350.8 g of acetic anhydride and refluxed at 100 °C ± 3 °C for 8 h. The resulting reaction solution was cooled to below 10 °C, filtered, and dried under vacuum to obtain 128.7 g of p-phenylene-bisphenyltriptyl dianhydride.
[0044] Upon testing, the p-phenylene-bisphenyltriterpenoid dianhydride obtained in this embodiment was found to be a white powder with a yellowness of less than 2, containing 347.69 ppb of metal ions, a total chlorine yield of 3.77 ppm, a yield of 77.35%, and a content of 99.50%.
[0045] Example 4: A method for preparing p-phenylene-bis(phenyltripterygium dianhydride), comprising the following steps: Under nitrogen protection, 165.1 g (0.784 mol) of trimellitic anhydride chloride dissolved in 600 g of acetonitrile is added to a reaction flask as the bottom liquid phase; 40 g (0.363 mol) of hydroquinone, 93.8 g (0.726 mol) of N,N-diisopropylethylamine, and 28.7 g (0.363 mmol) of pyridine are dissolved in 600 g of acetonitrile as the dropping phase; the dropping phase is added dropwise to the bottom liquid phase at room temperature, the temperature is controlled below 35°C, the dropping time is controlled at 6 h, and the temperature is maintained for 2 h after the addition. After the reaction is complete, the mixture is filtered, and the filter cake is treated with 600 g of acetonitrile solution. Washed with N,N-dimethylacetamide and dried under vacuum, 182.25 g of crude p-phenylene-bisphenyltriptyl dianhydride was obtained. 185.25 g of crude p-phenylene-bisphenyltriptyl dianhydride was added to 2 kg of water, heated to 60 °C and held at that temperature for 4 h. The resulting reaction solution was cooled to below 10 °C, filtered, and dried to obtain 145.8 g of crude p-phenylene-bisphenyltriptyl dianhydride recrystallized from water. 145.8 g of crude p-phenylene-bisphenyltriptyl dianhydride recrystallized from water was added to 309.6 g of acetic anhydride, heated to 100 °C ± 3 °C and refluxed for 8 h. The resulting reaction solution was cooled to below 10 °C, filtered, and dried under vacuum to obtain 104.6 g of p-phenylene-bisphenyltriptyl dianhydride.
[0046] Upon testing, the p-phenylene-bisphenyltrilate dianhydride obtained in this embodiment was found to be a white powder with a yellowness of less than 1, containing 450.6 ppb of metal ions, a total chlorine yield of 4.66 ppm, a yield of 62.87%, and a content of 99.74%.
[0047] Example 5: A method for preparing p-phenylene-bis(phenyltripterygium dianhydride), comprising the following steps: Under nitrogen protection, 165.1 g (0.784 mol) of trimellitic anhydride chloride dissolved in 600 g of acetonitrile is added to a reaction flask as the bottom liquid phase; 40 g (0.363 mol) of hydroquinone, 93.8 g (0.726 mol) of N,N-diisopropylethylamine, and 28.7 g (0.363 mmol) of pyridine are dissolved in 600 g of acetonitrile as the dropping phase; the dropping phase is added dropwise to the bottom liquid phase at room temperature, the temperature is controlled below 35°C, the dropping time is controlled at 6 h, and the temperature is maintained for 2 h after the addition. After the reaction is complete, the mixture is filtered, and the filter cake is treated with 600 g of acetonitrile solution. Washed with N,N-dimethylacetamide and dried under vacuum, 180 g of crude p-phenylene-bisphenyltriptyl dianhydride was obtained. The crude p-phenylene-bisphenyltriptyl dianhydride was added to 1.5 kg of dichloromethane, heated to 40 °C and held at that temperature for 2 h. The resulting reaction solution was cooled to below 10 °C, filtered, and dried to obtain 150.1 g of crude p-phenylene-bisphenyltriptyl dianhydride recrystallized from acetic anhydride. The crude p-phenylene-bisphenyltriptyl dianhydride recrystallized from 150.1 g was added to 309.6 g of acetic anhydride, heated to 100 °C ± 3 °C and refluxed for 8 h. The resulting reaction solution was cooled to below 10 °C, filtered, and dried under vacuum to obtain 108.07 g of p-phenylene-bisphenyltriptyl dianhydride.
[0048] Upon testing, the p-phenylene-bisphenyltrilate dianhydride obtained in this embodiment was found to be a white powder with a yellowness of less than 1, containing 428.2 ppb of metal ions, a total chlorine yield of 3.76 ppm, a yield of 64.96%, and a content of 99.54%.
[0049] Example 6: A method for preparing p-phenylene-bis(phenyltripterygium ester) dianhydride, comprising the following steps: Under nitrogen protection, 165.1 g (0.784 mol) of trimellitic anhydride chloride dissolved in 600 g of acetonitrile is added to a reaction flask as the bottom liquid phase; 40 g (0.363 mol) of hydroquinone and 86.1 g (1.089 mmol) of pyridine are dissolved in 600 g of acetonitrile as the dropping phase; the dropping phase is added dropwise to the bottom liquid phase at room temperature, the temperature is controlled below 35°C, the dropping time is controlled at 6 h, and the temperature is maintained for 2 h after the addition. After the reaction is complete, the mixture is filtered, and the filter cake is treated with 600 g of acetonitrile solution. Washed with N,N-dimethylacetamide and dried under vacuum, 184.1 g of crude p-phenylene-bisphenyltriptyl dianhydride was obtained. This crude p-phenylene-bisphenyltriptyl dianhydride was added to 1.5 kg of tetrahydrofuran, heated to 40 °C and held at that temperature for 2 h. The resulting reaction solution was cooled to below 10 °C, filtered, and dried to obtain 144.4 g of crude p-phenylene-bisphenyltriptyl dianhydride recrystallized from acetic anhydride. This crude p-phenylene-bisphenyltriptyl dianhydride recrystallized from acetic anhydride was added to 309.6 g of acetic anhydride, heated to 100 °C ± 3 °C and refluxed for 8 h. The reaction solution was cooled to below 10 °C, filtered, and dried under vacuum to obtain 83.18 g of p-phenylene-bisphenyltriptyl dianhydride.
[0050] According to the test results, the p-phenylene-bisphenyltrilate dianhydride obtained in this example is a white powder with a yellowness of less than 1, containing 428.2 ppb of metal ions, a total chlorine yield of 3.76 ppm, a yield of 50%, and a content of 99.05%.
[0051] In Example 7, under nitrogen protection, 165.1 g (0.784 mol) of trimellitic anhydride chloride dissolved in 600 g of acetonitrile was added to the reaction flask as the bottom liquid phase; 40 g (0.363 mol) of hydroquinone, 93.8 g (0.726 mol) of N,N-diisopropylethylamine, and 28.7 g (0.363 mmol) of pyridine were dissolved in 600 g of acetonitrile as the dropping phase; the dropping phase was added dropwise to the bottom liquid phase at room temperature, controlled below 35°C, for 6 h; after the addition, the temperature was maintained for 2 h; after the reaction was complete, the mixture was filtered, and the filter cake was collected using 600 g of acetonitrile solution. Washed with N,N-dimethylacetamide and dried under vacuum, 191.5 g of crude p-phenylene-bisphenyltriptyl dianhydride was obtained. The crude p-phenylene-bisphenyltriptyl dianhydride was added to 1.5 kg of tetrahydrofuran, heated to 40 °C and held for 2 h. The resulting reaction solution was cooled to below 10 °C, filtered, and dried to obtain 145.8 g of crude p-phenylene-bisphenyltriptyl dianhydride recrystallized from acetic anhydride. The crude p-phenylene-bisphenyltriptyl dianhydride recrystallized from acetic anhydride was added to 309.6 g of acetic anhydride, heated to 100 °C and reacted for 8 h. The reaction solution was cooled to below 10 °C, filtered, and dried under vacuum to obtain 133.1 g of p-phenylene-bisphenyltriptyl dianhydride.
[0052] Upon testing, the p-phenylene-bisphenyltrilate dianhydride obtained in this embodiment was found to be a white powder with a yellowness of less than 1, containing 428.2 ppb of metal ions, a total chlorine yield of 4.43 ppm, a yield of 80%, and a content of 99.52%.
[0053] Comparative Example 1: A method for preparing p-phenylene-bis(phenyltripterygium dianhydride) comprising the following steps: Under nitrogen protection, 165.1 g (0.784 mol) of trimellitic anhydride chloride dissolved in 600 g of acetonitrile is added to a reaction flask as the bottom liquid phase; 40 g (0.363 mol) of hydroquinone, 93.8 g (0.726 mol) of N,N-diisopropylethylamine, and 28.7 g (0.363 mmol) of pyridine are dissolved in 600 g of acetonitrile as the dropping phase; the dropping phase is added dropwise to the bottom liquid phase at room temperature, and the temperature is controlled below 35°C. After the reaction is complete, the mixture is filtered, and the filter cake is treated with 600 g of acetonitrile solution. Washed with N,N-dimethylacetamide and dried under vacuum, crude p-phenylene-bisphenyltriptate dianhydride was obtained. The crude p-phenylene-bisphenyltriptate dianhydride was added to 1.5 kg of tetrahydrofuran, heated to 40 °C and kept at that temperature for 2 h. The resulting reaction solution was cooled to below 10 °C, filtered, and dried to obtain 145.8 g of p-phenylene-bisphenyltriptate dianhydride.
[0054] The p-phenylene-bisphenyltriterpenoid dianhydride obtained in this comparative example is a white powder with a yellowness of less than 1, containing 821.9 ppb of metal ions, a total chlorine yield of 7.87 ppm, a yield of 87%, and a content of 85%.
[0055] The main difference between Example 7 and Comparative Example 1 is that Example 7 adds acetic anhydride treatment, which can improve product purity and better remove metal ions.
[0056] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention shall be considered equivalent substitutions and shall be included within the protection scope of the present invention.
Claims
1. A method for preparing p-phenylene-bisphenyltriester dianhydride, characterized in that, Includes the following steps: Trimeric trichlorohydrin, hydroquinone, and a catalyst are mixed and reacted to obtain crude p-phenylene-bisphenyltrimeric dianhydride; the crude p-phenylene-bisphenyltrimeric dianhydride is recrystallized and then mixed with acetic anhydride to obtain the p-phenylene-bisphenyltrimeric dianhydride; the catalyst includes at least one selected from pyridine, triethylamine, N,N-diisopropylethylamine, diethylamine, and dimethylamine.
2. The preparation method according to claim 1, characterized in that, The catalyst comprises pyridine and N,N-diisopropylethylamine; wherein the mass ratio of pyridine to N,N-diisopropylethylamine in the catalyst is 1:(1~3).
3. The preparation method according to claim 1, characterized in that, The molar ratio of hydroquinone, trimellitic anhydride chloride and catalyst is 1:(2~5):(2~5).
4. The preparation method according to claim 1, characterized in that, The recrystallized crude p-phenylene bisphenyltriterpenoid dianhydride has a mass ratio of 1:(1~4) to the acetic anhydride.
5. The preparation method according to claim 1, characterized in that, The preparation method includes the following steps: mixing trimellitic anhydride chloride with a first solvent to form a homogeneous solution, obtaining a bottom liquid phase; mixing hydroquinone and a catalyst with the first solvent to form a homogeneous solution, obtaining a dropwise phase; adding the dropwise phase dropwise to the bottom liquid phase to carry out a first reaction; after the first reaction is completed, performing solid-liquid separation to obtain a crude p-phenylene-bisphenyltriptyl dianhydride; redissolving and crystallizing the crude p-phenylene-bisphenyltriptyl dianhydride to obtain a recrystallized crude product; mixing the recrystallized crude product with acetic anhydride to carry out a second reaction to obtain the p-phenylene-bisphenyltriptyl dianhydride.
6. The preparation method according to claim 5, characterized in that, The temperature of the first reaction is ≤35℃; and / or the temperature of the second reaction is 80~120℃.
7. The preparation method according to claim 5, characterized in that, After solid-liquid separation, the obtained solid is washed and dried with a second solvent to obtain crude p-phenylene bisphenyltriterpenoid dianhydride.
8. The preparation method according to claim 5, characterized in that, The resolution and crystallization process includes the following steps: adding the crude p-phenylene-bisphenyltrilate dianhydride to a third solvent, heating to 30-70°C and holding for 1-5 hours, then cooling to below 10°C, and separating the solid and liquid phases to obtain the recrystallized crude product; or, adding the crude p-phenylene-bisphenyltrilate dianhydride to a third solvent, cooling to below 10°C and holding for 2-6 hours, and separating the solid and liquid phases to obtain the recrystallized crude product.
9. The preparation method according to claim 5 or any one of claims 7-8, characterized in that, The first solvent includes at least one of dichloromethane and acetonitrile; and / or the second solvent includes at least one of tetrahydrofuran, toluene, acetonitrile, ethyl acetate, and N,N-dimethylacetamide; and / or the third solvent includes at least one of water, chloroform, dichloromethane, acetone, and N,N-dimethylacetamide.
10. The preparation method according to claim 5 or 6, characterized in that, The second reaction includes the following steps: mixing the recrystallized crude product with acetic anhydride, heating to 80~120℃ to carry out the second reaction; after the second reaction is completed, cooling to below 10℃ to carry out solid-liquid separation to obtain the p-phenylene-bisphenyltriester dianhydride.