Preparation method of alicyclic aromatic diamine-containing monomer
Through the nucleophilic substitution reaction and hydrogenation reduction method of 4,4'-dinitroblasted phenylmethane and aliphatic dihalogenate, the problems of high temperature, long-term, high energy consumption, high cost and low yield of synthesis of alicyclic aromatic diamine monomers in the prior art are solved, and a simple and efficient preparation process is achieved.
Patent Information
- Application Number
- CN202510501766.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-04-21
- Publication Date
- 2025-08-15
AI Technical Summary
The prior art methods for synthesizing alicyclic aromatic diamine monomers have problems such as high reaction temperature, long time, large energy consumption, high cost, low yield and poor universality.
The nucleophilic substitution reaction was carried out with 4,4'-dinitroblastomer and aliphatic dihalogenate under alkaline conditions to form the intermediate di(4-nitrophenyl)-substituted cycloalkanes, and then alicycloaliphatic aromatic diamine monomer was obtained by hydrogenation reduction.
It has achieved a great shortening of reaction time, reduced temperature, simple post-treatment, improved yield, wide applicability, and suitable for industrial production.
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Abstract
Description
Technical Field
[0001] The invention relates to a method for preparing a material intermediate, in particular to a method for preparing an alicyclic aromatic diamine monomer, and belongs to the field of organic synthesis. Background Art
[0002] Polyimide (PI) is a polymer material with excellent comprehensive properties. Due to its excellent thermal stability, chemical resistance, dimensional stability, low dielectric constant, and low water absorption, it is widely used in a wide range of fields, including aerospace, medical devices, and semiconductors. However, due to its conjugated aromatic backbone and charge transfer effect, traditional PIs are mostly yellow to dark brown in color and have low transmittance in the visible light range, which seriously limits their application in optical materials such as liquid crystal alignment films and semiconductor materials. Current solutions to this problem include the introduction of alicyclic monomers, fluorinated monomers, bulky steric substituents, and rigid non-coplanar structures. Among these, the introduction of alicyclic monomers has attracted considerable attention due to the low cost and availability of raw materials.
[0003] The method for synthesizing alicyclic diamine monomers represented by 1,1-bis(4-aminophenyl)cyclohexane (BACH) mainly involves reacting an excess of aromatic amine with a cycloalkyl ketone under the catalysis of an acid such as hydrochloric acid, or directly reacting the hydrochloride of the amine with the cycloalkyl ketone to produce an alicyclic aromatic diamine hydrochloride, which is then alkalized and purified to obtain the diamine monomer.
[0004]
[0005] Although this method has been widely used to synthesize a variety of such monomers, the following problems still exist:
[0006] 1) The reaction temperature is high (120-150°C), and the reaction needs to be carried out in a pressure autoclave. The reaction time is very long (generally 20-40 hours), and the energy consumption is huge.
[0007] 2) Aromatic amines need to be used in large excess (3 to 5 equivalents), otherwise the reaction will be incomplete or polymerize, which is not in line with atom economy.
[0008] 3) Post-treatment requires operations such as activated carbon decolorization, benzene recrystallization or column chromatography, which are costly and inconvenient to operate in production.
[0009] 4) Low yields and poor universality. Reported yields for 1,1-bis(4-aminophenyl)cyclohexane (BACH) containing six-membered rings are generally between 32% and 60%, while those containing five-membered and seven-membered rings are only 4% and 2% (ChemPlusChem 2019, 84, 1145-1148). Furthermore, there are no reports of syntheses containing larger or smaller alicyclic rings. Summary of the Invention
[0010] The present invention aims to provide a method for preparing an alicyclic aromatic diamine monomer, which has the advantages of simple operation, mild conditions, high yield and universal applicability.
[0011] In order to achieve the above object, the technical solution of the present invention is as follows:
[0012] The present invention provides a method for synthesizing an alicyclic aromatic diamine monomer, comprising the following steps:
[0013] (1) Using 4,4'-dinitrodiphenylmethane as a raw material, a nucleophilic substitution reaction is carried out with an aliphatic dihalide under alkaline conditions to form an intermediate di(4-nitrophenyl)-substituted cycloalkane;
[0014] (2) The di(4-nitrophenyl)-substituted cycloalkane obtained in step (1) is subjected to catalytic hydrogenation reduction to obtain a finished alicyclic aromatic diamine monomer.
[0015] In the above technical solution, further, in step (1), the aliphatic dihalide is one of 1,3-dihalopropane, 1,4-dihalobutane, 1,5-dihalopentane, 1,6-dihalohexane, and 1,7-dihaloheptane, wherein the halogen is one or two of chlorine, bromine, and iodine;
[0016] The di(4-nitrophenyl)-substituted cycloalkane is shown in formula (I);
[0017]
[0018] In step (2), the finished product contains an alicyclic aromatic diamine monomer as shown in formula (II).
[0019]
[0020] In the above technical solution, further, in step (1), the aliphatic dihalide is one of 1,4-bis-halomethyl-cyclohexane and 1,3-bis-halomethyl-cyclopentane, wherein the halogen is one or two of chlorine, bromine, and iodine;
[0021] The di(4-nitrophenyl) substituted cycloalkane is as shown in formula (I');
[0022]
[0023] In step (2), the finished product contains an alicyclic aromatic diamine monomer as shown in formula (II').
[0024]
[0025] In the above technical solution, further, in step (1), the molar ratio of the 4,4'-dinitrodiphenylmethane to the aliphatic dihalide is 1:0.9 to 1:1.5.
[0026] In the above technical solution, further, in step (1), the base used in the alkaline condition is one of potassium hydroxide, sodium hydroxide, potassium carbonate, cesium carbonate, sodium methoxide, potassium methoxide, sodium ethoxide, potassium ethoxide, potassium tert-butoxide, sodium tert-butoxide, sodium hydrogen, n-butyl lithium, tert-butyl lithium, sodium amide, lithium bistrimethylsilylamide, sodium bistrimethylsilylamide, and potassium bistrimethylsilylamide, and the molar ratio of the base to the raw material 4,4'-dinitrodiphenylmethane is 2:1 to 3:1.
[0027] In the above technical solution, further, in step (1), the reaction temperature is 20-120°C, preferably 30-60°C.
[0028] In the above technical solution, further, in step (1), the solvent is one or a mixed solvent of two selected from the group consisting of DMF, DMA, DMSO, NMP, HMDA, tetrahydrofuran, acetonitrile, acetone, sulfolane, and water, preferably DMF or DMSO.
[0029] In the above technical solution, further, in step (2), the solvent used in the hydrogenation reduction reaction is one or a mixture of two of toluene, ethyl acetate, methanol, ethanol, isopropanol, and n-butanol.
[0030] In the above technical solution, further, in step (2), the catalyst used in the hydrogenation reduction reaction is one of palladium carbon, platinum carbon, and Raney nickel, and the weight ratio of the catalyst to the di(4-nitrophenyl)-substituted cycloalkane is 0.5% to 5%.
[0031] In the above technical solution, further, in step (2), the temperature of the hydrogenation reduction reaction is 20 to 120°C, preferably 60 to 80°C.
[0032] The present invention adopts a novel synthesis method to synthesize alicyclic aromatic diamines. The method uses 4,4'-dinitrodiphenylmethane as a raw material, undergoes a nucleophilic substitution reaction with an aliphatic dihalide under alkaline conditions to form an intermediate di(4-nitrophenyl)-substituted cycloalkane, and then undergoes hydrogenation reduction to obtain the alicyclic aromatic diamines. The present invention has simpler operation steps, mild conditions, higher yields, and good universality. It also avoids the problems of high temperature, long time, and complex post-processing in existing processes. It is more environmentally friendly and easy to implement industrial production.
[0033] The reaction formula is as follows:
[0034]
[0035] Compared with the prior art, the beneficial effects of the present invention are embodied in:
[0036] (1) The reaction time is greatly shortened. Although it is a two-step reaction, it can be completed within a few hours.
[0037] (2) The reaction temperature is lower. Compared with the existing process which requires a reaction temperature of at least 120°C, the present invention can complete the reaction at a temperature lower than 80°C.
[0038] (3) The post-processing of the present invention is relatively simple, and a white solid product can be obtained without the need for activated carbon decolorization, column chromatography and other operations.
[0039] (4) The present invention has wide applicability and can be used to synthesize alicyclic aromatic diamines containing cyclobutane, cyclopentane, cycloheptane and bridged rings, and the yield is much higher than that of the prior art. BRIEF DESCRIPTION OF THE DRAWINGS
[0040] Figure 1 This is the ESI-MS spectrum of the intermediate 1,1-di(4-nitrophenyl)cyclobutane prepared in Example 1;
[0041] Figure 2 This is the ESI-MS spectrum of the finished product 1,1-bis(4-aminophenyl)cyclobutane obtained in Example 1;
[0042] Figure 3 This is the ESI-MS spectrum of the intermediate 1,1-di(4-nitrophenyl)cyclopentane prepared in Example 2;
[0043] Figure 4 This is the ESI-MS spectrum of the finished product 1,1-bis(4-aminophenyl)cyclopentane obtained in Example 2;
[0044] Figure 5 This is the ESI-MS spectrum of the intermediate 1,1-di(4-nitrophenyl)cyclohexane prepared in Example 3;
[0045] Figure 6 This is the ESI-MS spectrum of the finished product 1,1-bis(4-aminophenyl)cyclohexane obtained in Example 3;
[0046] Figure 7 This is the ESI-MS spectrum of the intermediate 1,1-di(4-nitrophenyl)cycloheptane prepared in Example 4;
[0047] Figure 8 This is the ESI-MS spectrum of the finished product 1,1-bis(4-aminophenyl)cycloheptane obtained in Example 4;
[0048] Figure 9 This is the ESI-MS spectrum of the intermediate 1,1-bis(4-nitrophenyl)cyclooctane prepared in Example 5;
[0049] Figure 10 This is the ESI-MS spectrum of the finished product 1,1-bis(4-aminophenyl)cyclooctane obtained in Example 5;
[0050] Figure 11 This is the ESI-MS spectrum of the intermediate 3,3-bis(4-nitrophenyl)bicyclo[3.2.2]nonane prepared in Example 6;
[0051] Figure 12 This is the ESI-MS spectrum of the finished product 3,3-bis(4-aminophenyl)bicyclo[3.2.2]nonane obtained in Example 6. DETAILED DESCRIPTION
[0052] The following examples may enable those skilled in the art to more fully understand the present invention, but are not intended to limit the present invention in any way.
[0053] Unless otherwise specified, the materials used in the examples of the present invention can be obtained from commercial sources or prepared according to conventional methods well known to those skilled in the art.
[0054] Example 1
[0055]
[0056] Step (1): Under nitrogen protection, 10.22 g of sodium hydroxide (60%, dispersed in mineral oil) was added in batches to 240 mL of DMF. Under ice bath, 4,4'-dinitrodiphenylmethane (30.0 g, 116.2 mmol), 1,3-dibromopropane (24.6 g, 122.0 mmol) and 65 mL of The DMF mixed solution was slowly added dropwise to the mixture of sodium hydrogen and DMF, controlling the temperature not to exceed 20° C. The addition was completed over about 30 minutes, the ice bath was removed, and the mixture was stirred at room temperature for 3 hours. The reaction was controlled to be complete by HPLC, 240 mL of purified water was added to quench the residual sodium hydrogen, and 180 mL of ethyl acetate was added and extracted three times. The organic phases were combined, washed with saturated brine, and distilled under reduced pressure at 50° C. to about 100 mL. During this period, solids precipitated, crystallized in an ice bath, filtered, and the filter cake was rinsed with a small amount of petroleum ether and then dried in vacuo at 60° C. to give 30.4 g of a light yellow solid intermediate 1,1-bis(4-nitrophenyl)cyclobutane with a purity of 99.0% (HPLC) and a molar yield of 87.7%.
[0057] The ESI-MS spectrum of this intermediate is shown in Figure 1 ,Depend on Figure 1 It can be seen that its molecular weight is 298 (MH);
[0058] Step (2): The intermediate (30.4 g, 101.9 mmol) obtained in step (1), 160 mL of ethanol and 304 mg of palladium carbon with a palladium loading of 3% were added to a 250 mL pressure reactor, and nitrogen and hydrogen were replaced 3 times each. The reaction was carried out at 0.8 MPa and 70° C. for about 2 hours until no hydrogen was absorbed. The temperature and pressure were kept for about 30 minutes, the pressure was released, the reactor was opened, and the catalyst was filtered out. The filtrate was cooled to room temperature, and a large amount of white solid precipitated. The solid was filtered, and the filter cake was rinsed with a small amount of ethanol. The wet product was vacuum dried at 60° C. to obtain 22.8 g of a white final product 1,1-bis(4-aminophenyl)cyclobutane with a purity of 99.5%. The molar yield of step (2) was 93.9%.
[0059] The total molar yield of the two steps is: 82.3%;
[0060] The ESI-MS spectrum of the target product is shown in Figure 2 ,Depend on Figure 2 It can be seen that its molecular weight is 238 (M+H).
[0061] Example 2
[0062]
[0063] Step (1): 4,4'-dinitrodiphenylmethane (30.0 g, 116.2 mmol), 1,4-dibromobutane (27.6 g, 127.8 mmol) and 350 mL of DMF were added to a 1 L three-necked flask. Under an ice bath, 10.22 g of sodium hydroxide (60%, dispersed in mineral oil) was added in batches, and the temperature was controlled not to exceed 20°C. The addition was completed over about 20 minutes, and the mixture was raised to 40°C and stirred for 4 hours. The reaction was controlled to be complete by HPLC. 100 mL of saturated aqueous ammonium chloride solution was added to quench the reaction. The reaction solution was extracted three times with 120 mL of ethyl acetate and washed once with water. Most of the ethyl acetate was removed from the organic phase by vacuum distillation. The remaining about 100 mL of solution was cooled to 0°C for crystallization, filtered, and the filter cake was dried in vacuo at 60°C to obtain 31.0 g of a light yellow solid intermediate 1,1-di(4-nitrophenyl)cyclopentane with a purity of 98.9% (HPLC) and a molar yield of 85.4%.
[0064] The ESI-MS spectrum of this intermediate is shown in Figure 3 ,Depend on Figure 3 It can be seen that its molecular weight is 312 (MH);
[0065] Step (2): The intermediate (31.0 g, 99.3 mmol) obtained in step (1), 130 mL of methanol and 300 mg of palladium carbon with a palladium loading of 3% were added to a 250 mL pressure reactor, and nitrogen and hydrogen were replaced 3 times each. The reaction was carried out at 0.8 MPa and 60° C. for about 2 hours until no hydrogen was absorbed. The temperature and pressure were kept for about 30 minutes, the pressure was released, the reactor was opened, and the catalyst was filtered out. The filtrate was cooled to room temperature, and a large amount of white solid precipitated. The solid was filtered, and the filter cake was rinsed with a small amount of methanol. The wet product was vacuum dried at 60° C. to obtain 24.1 g of a white final product 1,1-bis(4-aminophenyl)cyclopentane with a purity of 99.6% (HPLC). The molar yield of step (2) was 96.2%.
[0066] The total molar yield of the two steps is: 82.2%;
[0067] The ESI-MS spectrum of the target product is shown in Figure 4 ,Depend on Figure 4 It can be seen that its molecular weight is 252 (M+H).
[0068] Example 3
[0069]
[0070] Step (1): 4,4'-dinitrodiphenylmethane (40.0 g, 154.9 mmol), 1,5-dichloropentane (24.0 g, 170.4 mmol), sodium iodide (1.16 g, 7.74 mmol) and DMSO 300mL was added to a 1L three-necked flask, and 14.25g of sodium hydroxide (60%, dispersed in mineral oil) was added in batches under an ice bath. The temperature was controlled not to exceed 20°C and the addition was completed over about 20 minutes. The mixture was raised to 50°C and stirred for 3 hours. The reaction was controlled to be complete by HPLC. 120mL of saturated aqueous ammonium chloride solution was added to quench the reaction. The reaction solution was extracted three times with 150mL of ethyl acetate and washed twice with saturated brine. Most of the ethyl acetate was removed from the organic phase by distillation under reduced pressure. The remaining about 120mL of solution was cooled to 0°C for crystallization, filtered, and the filter cake was dried in vacuo at 60°C to obtain 45.8g of a light yellow solid intermediate 1,1-di(4-nitrophenyl)cyclohexane with a purity of 98.8% (HPLC) and a molar yield of 90.6%.
[0071] The ESI-MS spectrum of this intermediate is shown in Figure 5 ,Depend on Figure 5 It can be seen that its molecular weight is 326 (MH);
[0072] Step (2): The intermediate (45.8 g, 140.3 mmol) obtained in step (1), 130 mL of toluene and 400 mg of palladium carbon with a palladium loading of 3% were added to a 250 mL pressure reactor, and nitrogen and hydrogen were replaced 3 times each. The reaction was carried out at 0.8 MPa and 80° C. for about 2 hours until no hydrogen was absorbed. The temperature and pressure were kept for about 30 minutes, the pressure was released, the reactor was opened, and the catalyst was filtered out. The filtrate was cooled to room temperature, and a large amount of white solid precipitated. The solid was filtered, and the filter cake was rinsed with a small amount of petroleum ether. The wet product was vacuum dried at 60° C. to obtain 33.9 g of a white final product, 1,1-bis(4-aminophenyl)cyclohexane, with a purity of 99.8% (HPLC). The molar yield of step (2) was 90.7%.
[0073] The total molar yield of the two steps is: 82.2%;
[0074] The ESI-MS spectrum of the target product is shown in Figure 6 ,Depend on Figure 6 It can be seen that its molecular weight is 266 (M+H).
[0075] Example 4
[0076]
[0077] Step (1): 4,4'-dinitrodiphenylmethane (40.0 g, 154.9 mmol), 1,6-dichlorohexane (26.4 g, 170.4 mmol), sodium iodide (0.464 g, 3.10 mmol) and DMSO 320mL was added to a 1L three-necked flask, and 13.6g of sodium hydroxide (60%, dispersed in mineral oil) was added in batches under an ice bath. The temperature was controlled not to exceed 20°C and the addition was completed over about 20 minutes. The mixture was raised to 40°C and stirred for 5 hours. The reaction was controlled to be complete by HPLC. 150mL of saturated aqueous ammonium chloride was added to quench the reaction. The reaction solution was extracted three times with 160mL of ethyl acetate and washed twice with saturated brine. Most of the ethyl acetate was removed from the organic phase by distillation under reduced pressure. The remaining about 120mL solution was cooled to 0°C for crystallization, filtered, and the filter cake was dried in vacuo at 60°C to obtain 44.3g of a light yellow solid intermediate 1,1-bis(4-nitrophenyl)cycloheptane with a purity of 99.1% (HPLC) and a molar yield of 84.0%.
[0078] The ESI-MS spectrum of this intermediate is shown in Figure 7 ,Depend on Figure 7 It can be seen that its molecular weight is 340 (MH);
[0079] Step (2): The intermediate (44.3 g, 130.2 mmol) obtained in step (1), 90 mL of toluene and 400 mg of palladium carbon with a palladium loading of 3% were added to a 250 mL pressure reactor, and nitrogen and hydrogen were replaced 3 times each. The reaction was carried out at 0.8 MPa and 80° C. for about 2 hours until no hydrogen was absorbed. The temperature and pressure were kept for about 30 minutes, the pressure was released, the reactor was opened, and the catalyst was filtered out. The filtrate was cooled to room temperature, and a large amount of white solid precipitated. The solid was filtered, and the filter cake was rinsed with a small amount of petroleum ether. The wet product was vacuum dried at 60° C. to obtain 34.7 g of a white final product 1,1-bis(4-aminophenyl)cycloheptane with a purity of 99.7% (HPLC). The molar yield of step (2) was 95.1%.
[0080] The total molar yield of the two steps is: 79.9%;
[0081] The ESI-MS spectrum of the target product is shown in Figure 8 ,Depend on Figure 8 It can be seen that its molecular weight is 280 (M+H).
[0082] Example 5
[0083]
[0084] Step (1): 4,4'-dinitrodiphenylmethane (35.0 g, 135.5 mmol), 1,7-dibromoheptane (35.7 g, 138.3 mmol), potassium tert-butoxide (31.9 g, 284.6 mmol) and THF 500 mL were added to a 1 L three-necked flask, heated to 67 ° C and refluxed with stirring for 6 hours. The reaction was completed by HPLC control, and 250 mL of purified water was added to quench the reaction. The reaction solution was extracted three times with 200 mL of ethyl acetate and washed twice with saturated brine. Most of the ethyl acetate was removed by distillation under reduced pressure from the organic phase. 60 mL of petroleum ether was added to the remaining 120 mL of solution, and the temperature was lowered to 0 ° C to precipitate a solid. The solid was filtered and the filter cake was dried under vacuum at 60 ° C to obtain 43.4 g of a light yellow solid intermediate 1,1-di(4-nitrophenyl)cyclooctane with a purity of 98.6% (HPLC) and a molar yield of 90.4%.
[0085] The ESI-MS spectrum of this intermediate is shown in Figure 9 ,Depend on Figure 9 It can be seen that its molecular weight is 354 (MH);
[0086] Step (2): The intermediate (43.4 g, 122.5 mmol) obtained in step (1), 120 mL of toluene and 400 mg of palladium carbon with a palladium loading of 3% were added to a 250 mL pressure reactor, and nitrogen and hydrogen were replaced 3 times each. The reaction was carried out at 0.8 MPa and 80° C. for about 2 hours until no hydrogen was absorbed. The temperature and pressure were kept for about 30 minutes, the pressure was released, the reactor was opened, and the catalyst was filtered out. The filtrate was cooled to room temperature, and a large amount of white solid precipitated. The solid was filtered, and the filter cake was rinsed with a small amount of petroleum ether. The wet product was vacuum dried at 60° C. to obtain 32.9 g of a white final product 1,1-bis(4-aminophenyl)cyclooctane with a purity of 99.2% (HPLC). The molar yield of step (2) was 91.2%.
[0087] The total molar yield of the two steps is: 82.4%;
[0088] The ESI-MS spectrum of the target product is shown in Figure 10 ,Depend on Figure 10 It can be seen that its molecular weight is 294 (M+H).
[0089] Example 6
[0090]
[0091] Step (1): Under nitrogen protection, sodium hydroxide (7.43 g, 60%, dispersed in mineral oil, 185.9 mmol) was added to 320 mL of DMF. Under ice bath, 4,4'-dinitrodiphenylmethane (20.0 g, 77.5 mmol), 1,4-(dibromomethyl)cyclohexane (22.0 g, 81.3 mmol) and 80 mL of The DMF mixed solution was slowly added dropwise to the mixture of sodium hydrogen and DMF, controlling the temperature not to exceed 20°C. The addition was completed over about 30 minutes, the ice bath was removed, the temperature was raised to 60°C and stirred for 3 hours. The reaction was controlled complete by HPLC, 250 mL of purified water was added to quench the residual sodium hydrogen, 200 mL of ethyl acetate was added and extracted three times, the organic phases were combined, the organic phases were washed with purified water, and the mixture was distilled under reduced pressure at 50°C to about 80 mL. During this period, solids precipitated, crystallized in an ice bath, filtered, and the filter cake was rinsed with a small amount of petroleum ether and then dried in vacuo at 60°C to obtain 18.1 g of a light yellow solid intermediate 3,3-bis(4-nitrophenyl)bicyclo[3.2.2]nonane with a purity of 98.0% (HPLC) and a molar yield of 63.8%.
[0092] The ESI-MS spectrum of this intermediate is shown in Figure 11 ,Depend on Figure 11 It can be seen that its molecular weight is 366 (MH);
[0093] Step (2): The intermediate (18.1 g, 49.4 mmol) obtained in step (1), 100 mL of toluene and 180 mg of palladium carbon with a palladium loading of 3% were added to a 250 mL pressure reactor, and nitrogen and hydrogen were replaced 3 times each. The reaction was carried out at 0.8 MPa and 80° C. for about 2 hours until no hydrogen was absorbed. The temperature and pressure were kept for about 30 minutes, and the pressure was released. The reactor was opened and filtered to remove the catalyst. The filtrate was cooled to room temperature. A large amount of white solid precipitated, and the solid was filtered. The filter cake was rinsed with a small amount of petroleum ether, and the wet product was dried in vacuo at 60° C. to obtain 13.9 g of a white final product 3,3-bis(4-aminophenyl)bicyclo[3.2.2]nonane with a purity of 99.1% (HPLC). The molar yield of step (2) was 91.8%.
[0094] The total molar yield of the two steps is: 58.6%;
[0095] The ESI-MS spectrum of the target product is shown in Figure 12 ,Depend on Figure 12 It can be seen that its molecular weight is 306 (M+H).
[0096] Example 7
[0097]
[0098] Step (1): Under nitrogen protection, 4,4'-dinitrodiphenylmethane (20.0 g, 77.5 mmol) was added to 380 mL of THF. Under ice bath, sodium methoxide (10.04 g, 185.9 mmol) was added in batches. The temperature was controlled not to exceed 5 ° C. After stirring for 30 min, 1,4-(dibromomethyl)cyclohexane (22.0 g, 81.3 mmol) and 88 mL of The THF mixed solution was slowly added dropwise to the above reaction solution, controlling the temperature not to exceed 20°C. The addition was completed over about 30 minutes, the ice bath was removed, the temperature was raised to 67°C, and refluxed with stirring for 5 hours. The reaction was controlled complete by HPLC, 250 mL of purified water was added to quench the residual sodium methoxide, and 200 mL of ethyl acetate was added for extraction three times. The organic phases were combined, washed with purified water, and distilled under reduced pressure at 50°C to about 70 mL. During this period, solids precipitated. The mixture was crystallized in an ice bath and filtered. The filter cake was rinsed with a small amount of petroleum ether and then dried in vacuo at 60°C to obtain 19.1 g of a light yellow solid intermediate 3,3-bis(4-nitrophenyl)bicyclo[3.2.2]nonane with a purity of 98.0% (HPLC) and a molar yield of 70.2%.
[0099] Step (2): The intermediate (18.1 g, 49.4 mmol) obtained in step (1), 80 mL of toluene and 160 mg of platinum carbon with a platinum loading of 5% were added to a 250 mL pressure reactor, and nitrogen and hydrogen were replaced 3 times each. The reaction was carried out at 0.8 MPa and 80° C. for about 2 hours until no hydrogen was absorbed. The temperature and pressure were kept for about 30 minutes, and the pressure was released. The reactor was opened and filtered to remove the catalyst. The filtrate was cooled to room temperature. A large amount of white solid precipitated, which was filtered. The filter cake was rinsed with a small amount of petroleum ether. The wet product was vacuum dried at 60° C. to obtain 14.1 g of a white final product 3,3-bis(4-aminophenyl)bicyclo[3.2.2]nonane with a purity of 99.1% (HPLC). The molar yield of step (2) was 93.3%.
[0100] The total molar yield of the two steps is: 65.5%.
[0101] The above embodiments are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. The scope of protection of the present invention shall be determined by the scope defined in the claims. Other variations or modifications may be made based on the above description. Obvious variations or modifications derived therefrom shall remain within the scope of protection of the present invention.
Claims
1. A method for synthesizing a monomer containing alicyclic aromatic diamine, characterized in that: The steps include: (1) Using 4,4'-dinitrodiphenylmethane as a raw material, a nucleophilic substitution reaction is carried out with an aliphatic dihalide under alkaline conditions to form an intermediate di(4-nitrophenyl)-substituted cycloalkane; (2) The di(4-nitrophenyl)-substituted cycloalkane obtained in step (1) is subjected to catalytic hydrogenation reduction to obtain a finished alicyclic aromatic diamine monomer.
2. The method for preparing an alicyclic aromatic diamine monomer according to claim 1, wherein: In step (1), the aliphatic dihalide is one of 1,3-dihalopropane, 1,4-dihalobutane, 1,5-dihalopentane, 1,6-dihalohexane, and 1,7-dihaloheptane, wherein the halogen is one or two of chlorine, bromine, and iodine; The di(4-nitrophenyl)-substituted cycloalkane is shown in formula (I); In step (2), the finished product contains an alicyclic aromatic diamine monomer as shown in formula (II).
3. The method for preparing an alicyclic aromatic diamine monomer according to claim 1, wherein: In step (1), the aliphatic dihalide is one of 1,4-bis-halomethyl-cyclohexane and 1,3-bis-halomethyl-cyclopentane, wherein the halogen is one or two of chlorine, bromine and iodine; The di(4-nitrophenyl) substituted cycloalkane is as shown in formula (I'); In step (2), the finished product contains an alicyclic aromatic diamine monomer as shown in formula (II').
4. The method for preparing an alicyclic aromatic diamine monomer according to claim 1, wherein: In step (1), the molar ratio of 4,4'-dinitrodiphenylmethane to aliphatic dihalide is 1:0.9 to 1:1.
5.
5. The method for preparing an alicyclic aromatic diamine monomer according to claim 1, wherein: In step (1), the base used in the alkaline condition is one of potassium hydroxide, sodium hydroxide, potassium carbonate, cesium carbonate, sodium methoxide, potassium methoxide, sodium ethoxide, potassium ethoxide, potassium tert-butoxide, sodium tert-butoxide, sodium hydrogen, n-butyl lithium, tert-butyl lithium, sodium amide, lithium bistrimethylsilylamide, sodium bistrimethylsilylamide, and potassium bistrimethylsilylamide, and the molar ratio of the base to the raw material 4,4'-dinitrodiphenylmethane is 2:1 to 3:
1.
6. The method for preparing alicyclic aromatic diamine monomers according to claim 1, wherein: In step (1), the reaction temperature is 20-120°C, preferably 30-60°C.
7. The method for preparing an alicyclic aromatic diamine monomer according to claim 1, wherein: In step (2), the solvent used in the hydrogenation reduction reaction is one of toluene, ethyl acetate, methanol, ethanol, isopropanol, and n-butanol.
8. The method for preparing alicyclic aromatic diamine monomers according to claim 1, wherein: In step (2), the catalyst used in the hydrogenation reduction reaction is one of palladium carbon, platinum carbon, and Raney nickel, and the weight ratio of the catalyst to the di(4-nitrophenyl)-substituted cycloalkane is 0.5% to 5%.
9. The method for preparing alicyclic aromatic diamine monomers according to claim 1, wherein: In step (2), the temperature of the hydrogenation reduction reaction is 20 to 120°C, preferably 60 to 80°C.