2, 3, 3apos; , 4apos; synthetic method of-biphenyltetracarboxylic dianhydride

Abstract

The invention discloses a synthesis method of 2, 3, 3 ', 4'-biphenyltetracarboxylic dianhydride, which is characterized by comprising the following steps: taking 2, 3-dimethylaniline as an initial raw material, firstly carrying out diazotization reaction to prepare 2, 3-dimethylaniline diazonium salt, then carrying out coupling reaction on the 2, 3-dimethylaniline diazonium salt and o-xylene under the catalysis of cuprous chloride to prepare 2, 3, 3 ', 4'-tetramethyl biphenyl, and finally carrying out oxidation reaction and dehydration to form anhydride to prepare the 2, 3, 3 ', 4'-biphenyltetracarboxylic dianhydride. The invention discloses 4, 4 '-biphenyltetracarboxylic dianhydride. According to the synthesis method, the coupling reaction is good in selectivity, 3, 3, 4 ', 4'-tetramethyl biphenyl difficult to separate is not generated, alpha-BPDA with high purity can be obtained finally, only cuprous chloride low in price needs to be adopted as a catalyst in the coupling reaction in the synthesis method, the cost is low, and the cost is low. Compared with an expensive catalytic system in the prior art, the production cost is greatly reduced, and the method is more suitable for industrial mass production.

Description

Technical Field

[0001] The invention belongs to the technical field of organic synthesis, and particularly relates to a method for synthesizing 2,3,3',4'-biphenyltetracarboxylic dianhydride. Background Art

[0002] 2,3,3',4'-Biphenyltetracarboxylic dianhydride, referred to as a-BPDA, is a white solid with a melting point of 195-205°C and a molecular formula of C 16 H6O6, relative molecular weight is 294.22, CAS number is 36978-41-3, the structural formula is as follows: .

[0003] Polyimide has excellent mechanical properties, heat resistance, radiation resistance, low dielectric constant and hydrolysis resistance, and has been widely used in aerospace, national defense, electronic information and other fields. Among them, biphenyltetracarboxylic acid dianhydride polymers are one of the most widely used products in high-temperature resistant polyimide materials. Among biphenyltetracarboxylic acid dianhydride, asymmetric biphenyltetracarboxylic acid dianhydride (also known as 2,3,3',4'-biphenyltetracarboxylic acid dianhydride) can both increase the glass transition temperature of the material and reduce the melt viscosity of the resin, greatly improving the processing performance of the material.

[0004] At present, the methods for synthesizing 2,3,3',4'-biphenyltetracarboxylic dianhydride mainly include the following: (1) 3- and 4-halogenated phthalic acid diesters are cross-coupled, hydrolyzed, and dehydrated to obtain 2,3,3',4'-biphenyltetracarboxylic acid dianhydride [CN1436780A], or 3- and 4-halogenated phthalimides are cross-coupled, hydrolyzed, and dehydrated to obtain 2,3,3',4'-biphenyltetracarboxylic acid dianhydride [CN101481366A], or 3- and 4-o-xylene are cross-coupled, oxidized, and dehydrated to obtain 2,3,3',4'-biphenyltetracarboxylic acid dianhydride [CN101481366A], 2,3,3',4'-biphenyltetracarboxylic dianhydride [CN102020622A] can be prepared by water-to-anhydride, or 3- and 4-halogenated phthalic anhydride can be directly cross-coupled to obtain 2,3,3',4'-biphenyltetracarboxylic dianhydride [CN108250169A], or 3- and 4-halogenated phthalic acid can be cross-coupled + dehydrated to obtain 2,3,3',4'-biphenyltetracarboxylic dianhydride [CN118666788A].

[0005] The above methods have the following disadvantages: (1) The cross-coupling reaction has poor selectivity, and the three isomers are difficult to separate and purify, resulting in low purity of the target product 2,3,3',4'-biphenyltetracarboxylic dianhydride [the above literature does not have purity data of the target product]. (2) The cross-coupling reaction requires an expensive catalytic system, resulting in high production costs.

[0006] (2) Using 2,3-methylaniline as the starting material, 2,3-methylbromobenzene is first reacted to obtain 2,3-methylbenzene, which is then subjected to a Grignard reaction to obtain 2,3-dimethylphenylboronic acid, which is then reacted with N-methyl-4-chlorophthalimide in the presence of a palladium catalyst to obtain 5-(2,3-dimethylphenyl)-2-methylisoindole-1,3-dione, which is finally oxidized and dehydrated to obtain 2,3,3',4'-biphenyltetracarboxylic dianhydride [CN114230540A].

[0007] Although this method has high coupling reaction selectivity and high purity of the target product, it still has the following shortcomings: (1) It still needs to use an expensive catalytic system, resulting in high production costs; (2) The synthetic route is long and the overall yield is low, especially the format reaction has low safety, which is not suitable for large-scale industrial production.

[0008] (3) 4-Chlorophthalic acid diester is first reacted with diboric acid / diboric acid ester in the presence of a palladium catalyst to obtain an intermediate aryl boronic acid / boric acid ester, which is then coupled with 3-chlorophthalic acid ester to obtain 2,3,3',4'-biphenyltetracarboxylic acid tetraester, and finally hydrolyzed and dehydrated to anhydride to obtain 2,3,3',4'-biphenyltetracarboxylic acid dianhydride [CN115894416A].

[0009] Although this method has high coupling reaction selectivity and high purity of the target product, it still has the following shortcomings: (1) It still needs to use an expensive catalytic system, resulting in high production costs; (2) The coupling reaction temperature is high, resulting in high energy consumption, which is not suitable for large-scale industrial production.

[0010] (4) 3-Halogenated o-xylene is first reacted with a lithiation reagent to obtain 3-lithioated o-xylene, which is then coupled with 4-halogenated o-xylene to obtain 2,3,3',4'-tetramethylbiphenyl, which is finally oxidized and dehydrated to anhydride to obtain 2,3,3',4'-biphenyltetracarboxylic dianhydride [CN116478114A].

[0011] Although this method has high coupling reaction selectivity and high purity of the target product, it still has the following shortcomings: (1) It still needs to use an expensive catalytic system, resulting in high production costs; (2) The lithiation reaction conditions are harsh and the safety is low, which is not suitable for large-scale industrial production. Summary of the invention

[0012] The object of the present invention is to solve the above problems and provide a method for synthesizing 2,3,3',4'-biphenyltetracarboxylic dianhydride which has high coupling reaction selectivity and thus high purity of the target product and low catalytic system price and thus low production cost.

[0013] The technical scheme for achieving the purpose of the present invention is: a method for synthesizing 2,3,3',4'-biphenyltetracarboxylic dianhydride, characterized in that: 2,3-dimethylaniline is used as a starting material, 2,3-dimethylaniline diazonium salt is firstly prepared by diazotization reaction, then 2,3,3',4'-tetramethylbiphenyl is prepared by coupling reaction with o-xylene under the catalysis of cuprous chloride, and finally 2,3,3',4'-biphenyltetracarboxylic dianhydride is prepared by oxidation reaction and dehydration to anhydride.

[0014] The synthetic route is as follows: .

[0015] The 2,3-dimethylaniline diazonium salt is preferably a hydrochloride.

[0016] The diazotization reaction is carried out at a temperature of -10 to 10°C.

[0017] The coupling reaction is carried out in the presence of an organic solvent; the organic solvent is acetone or butanone.

[0018] The starting temperature of the coupling reaction is 45-56°C, and the reaction temperature after starting is 15-35°C.

[0019] The oxidation reaction is a conventional method in the art, such as pyridine-potassium permanganate method, catalyst-oxygen method, nitric acid method, etc.

[0020] The dehydration to anhydride is a conventional method in the art, such as heating dehydration of acetic anhydride to anhydride, solvent-free high-temperature dehydration to anhydride, and reflux dehydration of xylene to anhydride.

[0021] The present invention has the following positive effects: (1) The coupling reaction in the synthesis method of the present invention has good selectivity and only generates 2,3,3',4'-tetramethylbiphenyl and 2,2,3',3'-tetramethylbiphenyl, which are scarce and expensive intermediates of a-BPDA and i-BPDA in the market, but does not generate 3,3,4',4'-tetramethylbiphenyl, which is an intermediate of s-BPDA with relatively low added value. In particular, 2,3,3',4'-tetramethylbiphenyl and 2,2,3',3'-tetramethylbiphenyl can be effectively separated by distillation, while 3,3,4',4'-tetramethylbiphenyl is difficult to be separated from 2,3,3',4'-tetramethylbiphenyl by distillation, thereby obtaining 2,3,3',4'-tetramethylbiphenyl with higher purity, and finally obtaining a-BPDA with higher purity. (2) The coupling reaction in the synthesis method of the present invention only requires the use of inexpensive cuprous chloride as a catalyst, which greatly reduces the production cost compared to the expensive catalytic system in the prior art and is more suitable for large-scale industrial production. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1This is the HPLC spectrum of 2,3,3',4'-tetramethylbiphenyl prepared in Example 1.

[0023] Figure 2 This is the EI-MS spectrum of 2,3,3',4'-biphenyltetracarboxylic acid prepared in Example 1.

[0024] Figure 3 This is the ESI-MS spectrum of 2,3,3',4'-biphenyltetracarboxylic dianhydride prepared in Example 1 after using methanol for sample preparation. DETAILED DESCRIPTION

[0025] (Example 1) The synthesis method of 2,3,3',4'-biphenyltetracarboxylic dianhydride of the present embodiment comprises the following steps: S1. Diazotization reaction.

[0026] S11. Add 40.7 g of sodium nitrite (0.59 mol) into 72 g of water, stir to dissolve, and obtain a sodium nitrite aqueous solution for later use.

[0027] S12. Add 69.1 g of 2,3-dimethylaniline (0.57 mol) and 200 g of water into a reaction bottle, control the temperature at 0-30°C, add 130.5 g of 36 wt% concentrated hydrochloric acid, stir and dissolve after adding, to obtain 2,3-dimethylaniline hydrochloride.

[0028] S13, cool to -5 to 0°C, add the sodium nitrite aqueous solution obtained in step S11 dropwise (30 to 60 minutes to complete the addition), stir and react for 30 minutes, then slowly add 120 mL of acetone, stir and crystallize, filter, wash the filter cake with a small amount of acetone, and obtain 103 g of wet 2,3-dimethylaniline diazonium hydrochloride, which is directly used for the next step reaction.

[0029] S2. Coupling reaction.

[0030] S21. Add 200 mL of o-xylene (1.66 mol), 100 mL of acetone and 3 g of cuprous chloride into the reaction bottle, heat to 50°C, then add 10 g of the wet product of 2,3-dimethylaniline diazonium hydrochloride obtained in step ①, stir until a large amount of bubbles overflow, and the reaction starts.

[0031] S22, cool down to 20-30℃, add the remaining 93g of 2,3-dimethylaniline diazonium hydrochloride wet product in batches (add in 4 times, about 40 minutes), keep warm and stir until the reaction is complete.

[0032] S23, raising the temperature to 30-40°C, concentrating under reduced pressure to recover acetone, adding 100 mL of water to the residue, stirring, separating the layers, and washing the organic layer once more with 50 mL of water.

[0033] S24. The organic layer was first distilled under reduced pressure (bottom temperature 80°C, vacuum degree -0.95MPa) to remove the organic solvent, and the distillation residue was then rectified (bottom temperature 230°C, vacuum degree -0.98MPa) to obtain 25.8g of 2,2,3',3'-tetramethylbiphenyl at 265-270°C and 77.3g of 2,3,3',4'-tetramethylbiphenyl at 285-290°C.

[0034] The HPLC spectrum of 2,3,3',4'-tetramethylbiphenyl prepared in this example is shown in Figure 1 ,Depend on Figure 1 It can be seen that its purity is as high as 99.2%.

[0035] S3. Oxidation reaction.

[0036] S31. Add 300 mL of glacial acetic acid into a reaction bottle, add 60 g of 2,3,3',4'-tetramethylbiphenyl obtained in step S2, 1.6 g of cobalt acetate tetrahydrate, 1.1 g of manganese acetate and 3.2 g of sodium bromide in sequence under stirring, raise the temperature to 100-120° C., and introduce oxygen to react.

[0037] S32. After the reaction is completed, cool, filter, and concentrate under reduced pressure to recover the solvent. First, add 56 mL of water, then add 30 wt% sodium hydroxide aqueous solution to adjust the pH to 9, add 2.5 g of activated carbon, heat to 80-90°C, stir to decolorize for 30 minutes, filter, adjust the pH to 1-1.5 with 30 wt% hydrochloric acid, cool to crystallize, filter, and dry to obtain 85.5 g of white solid 2,3,3',4'-biphenyltetracarboxylic acid with a yield of 90.8% and a purity of 99.2%.

[0038] The EI-MS spectrum of the intermediate obtained in this example is shown in Figure 2 ,Depend on Figure 2 It can be seen that the molecular weight of the intermediate is 330 (M-1), which is consistent with 2,3,3',4'-biphenyltetracarboxylic acid.

[0039] S4, anhydride formation reaction.

[0040] Add 160 mL of toluene, 180 mL of acetic anhydride and 80 g of 2,3,3',4'-biphenyltetracarboxylic acid obtained in step S3 to the reaction bottle, heat to 105-110° C. to react until complete, cool, filter and dry to obtain 67.8 g of off-white solid 2,3,3',4'-biphenyltetracarboxylic dianhydride with a yield of 95.2%, a purity of 99.6% and a melting point of 196.5-197.5° C.

[0041] The ESI-MS spectrum of the target product obtained in this example after using methanol for sample preparation is shown in Figure 3 ,Depend on Figure 3It can be seen that the molecular weight of the target product is 294 (M-1), which is consistent with 2,3,3',4'-biphenyltetracarboxylic dianhydride.

[0042] (Example 2) The synthesis method of 2,3,3',4'-biphenyltetracarboxylic dianhydride of the present embodiment comprises the following steps: S1. Diazotization reaction.

[0043] S11. Add 203.5 g of sodium nitrite (2.95 mol) into 360 g of water, stir to dissolve, and obtain a sodium nitrite aqueous solution for later use.

[0044] S12. Add 345.5 g of 2,3-dimethylaniline (2.85 mol) and 1000 g of water into a reaction bottle, control the temperature at 0-30°C, add 652.5 g of 36 wt% concentrated hydrochloric acid, stir and dissolve after adding, to obtain 2,3-dimethylaniline hydrochloride.

[0045] S13, cool to -5-0°C, add the sodium nitrite aqueous solution obtained in step S11 dropwise (30-60 min to complete the addition), stir and react for 30 min, then slowly add 580 mL of acetone, stir and crystallize, filter, wash the filter cake with a small amount of acetone, and obtain 515 g of wet 2,3-dimethylaniline diazonium hydrochloride, which is directly used for the next step reaction.

[0046] S2. Coupling reaction.

[0047] S21. Add 1000 mL of o-xylene (8.3 mol), 500 mL of acetone and 15 g of cuprous chloride into the reaction bottle, heat to 50°C, then add 50 g of the wet product of 2,3-dimethylaniline diazonium salt obtained in step ①, stir until a large amount of bubbles overflow, and the reaction starts.

[0048] S22, cool down to 20-30°C, add the remaining 565g of 2,3-dimethylaniline diazonium hydrochloride wet product in batches (add in 6 portions, about 60 minutes), keep warm and stir until the reaction is complete.

[0049] S23, raising the temperature to 30-40°C, concentrating under reduced pressure to recover acetone, adding 500 mL of water to the residue, stirring, separating the layers, and washing the organic layer once with 250 mL of water.

[0050] S24. The organic layer was first distilled under reduced pressure (bottom temperature 80°C, vacuum degree -0.95MPa) to remove the organic solvent, and the distillation residue was then rectified (bottom temperature 230°C, vacuum degree -0.98MPa). 130.2 g (purity 98.9%) of 2,2,3',3'-tetramethylbiphenyl was obtained at 265-270°C, and 387.3 g (purity 99.3%) of 2,3,3',4'-tetramethylbiphenyl was obtained at 285-290°C.

[0051] S3. Oxidation reaction.

[0052] S31. Add 1500 mL of glacial acetic acid into a reaction bottle, add 300 g of 2,3,3',4'-tetramethylbiphenyl obtained in step S2, 8 g of cobalt acetate tetrahydrate, 5.5 g of manganese acetate and 16 g of sodium bromide in sequence under stirring, raise the temperature to 100-120° C., and introduce oxygen for reaction.

[0053] S32. After the reaction is completed, cool down, filter, and concentrate under reduced pressure to recover the solvent. First, add 280 mL of water, then add 30 wt% sodium hydroxide aqueous solution to adjust the pH to 9, add 12.5 g of activated carbon, heat to 80-90°C, stir and decolorize for 30 minutes, filter, adjust the pH to 1-1.5 with 30 wt% hydrochloric acid, cool and crystallize, filter, and dry to obtain 428.2 g of white solid 2,3,3',4'-biphenyltetracarboxylic acid with a yield of 90.9% and a purity of 99.3%.

[0054] ④Anhydride reaction.

[0055] Add 400 g of 2,3,3',4'-biphenyltetracarboxylic acid obtained in step S3 into the reaction bottle, heat to 210-220° C. under nitrogen purge and react for 2 h, cool and discharge to obtain 340.8 g of off-white solid 2,3,3',4'-biphenyltetracarboxylic dianhydride with a yield of 95.6%, a purity of 99.0%, and a melting point of 196.2-197.2° C.

[0056] (Example 3) The synthesis method of 2,3,3',4'-biphenyltetracarboxylic dianhydride of the present embodiment comprises the following steps: S1. Diazotization reaction.

[0057] S11. Add 42.6 g of sodium nitrite (0.62 mol) and 135 mL of water into a reaction bottle, stir to dissolve, then cool to 0°C, control the temperature at 0-5°C, and add a mixture of 14.9 mL of concentrated sulfuric acid, 59.8 mL of isoamyl alcohol and 37.5 mL of water (about 90 minutes to complete), and keep warm for 45 minutes. After the reaction is completed, separate the layers, wash the organic layer with ice water (50 mL × 2) to obtain an isoamyl nitrite solution, and refrigerate for later use.

[0058] S12. Add 69.1 g of 2,3-dimethylaniline (0.57 mol) and 200 mL of ethanol into a reaction bottle, control the temperature at 0-30°C, add 145 mL of 4 mol / L hydrogen chloride ethanol solution, stir and dissolve after addition, and obtain 2,3-dimethylaniline hydrochloride.

[0059] S13, cool to -5-0°C, add the isoamyl nitrite solution obtained in step S11 dropwise (30-60 min to complete the addition), stir and react for 30 min, then slowly add 100 mL of petroleum ether, stir and crystallize, filter, wash the filter cake with a small amount of petroleum ether, and obtain 105 g of wet 2,3-dimethylaniline diazonium hydrochloride, which is directly used for the next step reaction.

[0060] S2. Coupling reaction.

[0061] S21. Add 210 mL of o-xylene (1.74 mol), 100 mL of acetone and 3.1 g of cuprous chloride into the reaction bottle, heat to 50°C, then add 10 g of the wet product of 2,3-dimethylaniline diazonium hydrochloride obtained in step ①, stir until a large amount of bubbles overflow, and the reaction starts.

[0062] S22, cool down to 20-30℃, add the remaining 95g of 2,3-dimethylaniline diazonium hydrochloride wet product in batches (add in 4 times, about 40 minutes), keep warm and stir until the reaction is complete.

[0063] S23, raising the temperature to 30-40°C, concentrating under reduced pressure to recover acetone, adding 100 mL of water to the residue, stirring, separating the layers, and washing the organic layer once more with 50 mL of water.

[0064] S24. The organic layer was first distilled under reduced pressure (bottom temperature 80°C, vacuum degree -0.95MPa) to remove the organic solvent, and the distillation residue was then rectified (bottom temperature 230°C, vacuum degree -0.98MPa). 26.2 g (purity 98.6%) of 2,2,3',3'-tetramethylbiphenyl was obtained at 265-270°C, and 78.3 g (purity 99.3%) of 2,3,3',4'-tetramethylbiphenyl was obtained at 285-290°C.

[0065] S3. Oxidation reaction.

[0066] S31. Add 320 mL of glacial acetic acid into a reaction bottle, add 60 g of 2,3,3',4'-tetramethylbiphenyl obtained in step S2, 1.5 g of cobalt acetate tetrahydrate, 1.0 g of manganese acetate and 3.2 g of sodium bromide in sequence under stirring, raise the temperature to 100-120° C., and introduce oxygen to react.

[0067] S32. After the reaction is completed, cool down, filter, and concentrate under reduced pressure to recover the solvent. First, add 58 mL of water, then add 30 wt% sodium hydroxide aqueous solution to adjust the pH to 9, add 2.5 g of activated carbon, heat to 80-90°C, stir to decolorize for 30 minutes, filter, adjust the pH to 1-1.5 with 30 wt% hydrochloric acid, cool and crystallize, filter, and dry to obtain 85.8 g of white solid 2,3,3',4'-biphenyltetracarboxylic acid with a yield of 91.1% and a purity of 99.3%.

[0068] ④Anhydride reaction.

[0069] Add 150 mL of toluene, 170 mL of acetic anhydride and 80 g of 2,3,3',4'-biphenyltetracarboxylic acid obtained in step S3 to the reaction bottle, heat to 105-110° C. to react until complete, cool, filter and dry to obtain 68.0 g of off-white solid 2,3,3',4'-biphenyltetracarboxylic dianhydride with a yield of 95.4%, a purity of 99.5% and a melting point of 196.4-197.5° C.

[0070] (Example 4) The synthesis method of 2,3,3',4'-biphenyltetracarboxylic dianhydride of the present embodiment comprises the following steps: S1. Diazotization reaction, same as in Example 1.

[0071] S2, coupling reaction, same as in Example 1.

[0072] S3. Oxidation reaction.

[0073] Add 436 g of potassium permanganate (2.8 mol) and 500 mL of pyridine to the reaction bottle, then add 60 g (0.285 mol) of 2,3,3',4'-tetramethylbiphenyl obtained in step S2, heat to reflux and react for 20 h, filter and concentrate, add the concentrated residue to 150 g of water, adjust the pH to 2-3 with 2 mol / L hydrochloric acid, filter, wash with water and dry to obtain 83.7 g of white solid 2,3,3',4'-biphenyltetracarboxylic acid with a yield of 88.9% and a purity of 99.1%.

[0074] ④Anhydride reaction.

[0075] Add 170 mL of toluene, 180 mL of acetic anhydride and 80 g of 2,3,3',4'-biphenyltetracarboxylic acid obtained in step S3 to the reaction bottle, heat to 100-110°C for complete reaction, cool, filter and dry to obtain 67.8 g of off-white solid 2,3,3',4'-biphenyltetracarboxylic dianhydride with a yield of 95.1%, a purity of 99.7% and a melting point of 196.5-197.6°C.

Claims

1. A method for synthesizing 2,3,3',4'-biphenyltetracarboxylic dianhydride, characterized in that: Taking 2,3-dimethylaniline as the starting material, 2,3-dimethylaniline diazonium salt is firstly prepared by diazotization reaction, and then 2,3,3',4'-tetramethylbiphenyl is prepared by coupling reaction with o-xylene under the catalysis of cuprous chloride, and finally 2,3,3',4'-biphenyltetracarboxylic dianhydride is prepared by oxidation reaction and dehydration to anhydride.

2. The method for synthesizing 2,3,3',4'-biphenyltetracarboxylic dianhydride according to claim 1, characterized in that: The 2,3-dimethylaniline diazonium salt is 2,3-dimethylaniline diazonium hydrochloride.

3. The method for synthesizing 2,3,3',4'-biphenyltetracarboxylic dianhydride according to claim 1, characterized in that: The diazotization reaction is carried out at a temperature of -10 to 10°C.

4. The method for synthesizing 2,3,3',4'-biphenyltetracarboxylic dianhydride according to claim 1, characterized in that: The coupling reaction is carried out in the presence of an organic solvent; the organic solvent is acetone or butanone.

5. The method for synthesizing 2,3,3',4'-biphenyltetracarboxylic dianhydride according to claim 1, characterized in that: The starting temperature of the coupling reaction is 45-56°C, and the reaction temperature after starting is 15-35°C.

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