1, 5-naphthalene diisocyanate and preparation process thereof
By combining 1,5-naphthalene disulfonic acid derivatives with nitrogen sources/carbonyl precursors and phase transfer catalysts, the safety hazards and environmental issues in the preparation of 1,5-naphthalene diisocyanate are resolved, an efficient and stable preparation process is achieved, and product quality is improved.
Patent Information
- Application Number
- CN202510966883.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-07-14
- Publication Date
- 2025-10-17
AI Technical Summary
The existing preparation methods of 1,5-naphthalene diisocyanate have problems such as safety hazards, high environmental protection costs, complicated reaction steps, many side reactions, and low atom economy.
A combination of 1,5-naphthalene disulfonic acid derivatives, nitrogen sources/carbonyl precursors, phase transfer catalysts and reaction solvents was used to introduce sulfonic acid groups through sulfonation reaction, and amino groups and carbon dioxide were produced by decomposition of carbamate. The reaction rate was increased by combining a phase transfer catalyst, and the reaction conditions were optimized to prepare 1,5-naphthalene diisocyanate.
The green, environmentally friendly, highly efficient and high-quality preparation of 1,5-naphthalene diisocyanate is achieved, which reduces safety risks and environmental protection costs and improves reaction efficiency and product purity.
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Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to the technical field of organic synthesis, and in particular to a 1,5-naphthalene diisocyanate and a preparation process thereof. BACKGROUND
[0002] 1,5-naphthalene diisocyanate is an important organic synthesis intermediate, and has a wide application prospect in the field of high-performance materials due to its unique molecular structure and chemical properties. In the preparation of polyurethane elastomers, coatings, adhesives and other products, 1,5-naphthalene diisocyanate as a key raw material can endow the products with excellent mechanical properties, high and low temperature resistance and chemical corrosion resistance, and is an indispensable basic material for preparing high-end polyurethane products. At present, the preparation technology of 1,5-naphthalene diisocyanate mainly includes phosgene method and non-phosgene method. The traditional phosgene method uses 1,5-naphthalene diamine as raw material and reacts with toxic phosgene. Although this method is relatively direct and has relatively high yield, the use of phosgene has great safety hazards. Phosgene has high toxicity and strong corrosion, and once leakage occurs during production, storage and transportation, it will cause serious harm to the health of the operators and the surrounding environment. In addition, a large amount of waste water and waste gas containing chlorine will be generated during the reaction process of the phosgene method, which is difficult to handle and has high environmental protection cost, and does not meet the requirements of green chemistry and sustainable development. The non-phosgene method for preparing 1,5-naphthalene diisocyanate overcomes the safety and environmental problems of the phosgene method to some extent. Some non-phosgene methods use carbonic acid dimethyl ester and other carbonyl reagents to replace phosgene to prepare the target product through reactions such as thermal decomposition of carbamic acid ester. However, these methods still have many deficiencies. For example, in the selection of raw materials, some schemes use 1,5-dimethylnaphthalene and other raw materials, and in the process of converting the target product through oxidation and other reactions, there are problems such as complicated reaction steps, many side reactions and low atom economy. Therefore, it is a technical problem to be solved in the field to develop a green and environmentally friendly, efficient and stable 1,5-naphthalene diisocyanate preparation method. SUMMARY
[0003] In view of the problems in the prior art, the present application provides a 1,5-naphthalene diisocyanate and a preparation process thereof.
[0004] To achieve the above object, the present application is realized by the following technical scheme: The present application discloses a 1,5-naphthalene diisocyanate, and the composition of the 1,5-naphthalene diisocyanate includes the following raw materials by weight: 1,5-naphthalene disulfonic acid derivative 40-60 g, nitrogen source / carbonyl precursor 25-35 g, phase transfer catalyst 3-7 g and reaction solvent 600-900 mL.
[0005] Preferably, the components of 1,5-naphthalene diisocyanate include the following raw materials by weight: 1,5-naphthalene disulfonic acid derivative 50 g, nitrogen source / carbonyl precursor 30 g, phase transfer catalyst 5 g and reaction solvent 750 mL.
[0006] Preferably, the 1,5-naphthalene disulfonic acid derivative is one of 1,5-naphthalene disulfonic acid or 1,5-naphthalene disulfonic acid disodium salt, the nitrogen source / carbonyl precursor is one of ethyl carbamate or butyl carbamate, and the phase transfer catalyst is one of hexadecyl trimethyl ammonium bromide or dodecyl trimethyl ammonium chloride.
[0007] By setting the above technical solution, the 1,5-naphthalene disulfonic acid derivative can provide a naphthalene ring skeleton, and the sulfonic acid group thereof can be substituted in the subsequent reaction to provide a basis for constructing the structure of 1,5-naphthalene diisocyanate; the strong electron-withdrawing effect of the sulfonic acid group reduces the electron cloud density of the naphthalene ring, which is conducive to the attack of the nucleophile, and the acidity thereof can play a certain proton transfer role in the reaction system. Ethyl carbamate or butyl carbamate decomposes to produce amino and carbon dioxide, and the amino group acts as a nucleophile to undergo a substitution reaction with the sulfonic acid group in the 1,5-naphthalene disulfonic acid derivative to gradually construct the isocyanate group structure; the generation of carbon dioxide helps to maintain a weakly acidic environment in the reaction system, promoting the reaction to proceed. As a phase transfer catalyst, hexadecyl trimethyl ammonium bromide or dodecyl trimethyl ammonium chloride has lipophilicity with the long-chain alkyl group capable of interacting with the organic phase, while the quaternary ammonium cation part has hydrophilicity and can combine with ions in the aqueous phase. In the reaction system, it can transfer the reactants or catalysts in the aqueous phase to the organic phase, so that the reactants originally in different phases can fully contact, greatly improving the reaction rate. N,N-dimethylformamide or N-methyl pyrrolidone has a high dielectric constant and good solubility for ionic and polar compounds, and in the reaction, it can dissolve 1,5-naphthalene disulfonic acid, ethyl carbamate and various intermediates generated during the reaction to form a uniform reaction system, allowing the reaction molecules to move freely and increasing the probability of effective collision, thereby accelerating the reaction rate.
[0008] Preferably, the preparation method of 1,5-naphthalene disulfonic acid is as follows: a1, take 100 g of naphthalene and add it to a four-necked flask, slowly drop 260 g of 98% concentrated sulfuric acid while stirring at a speed of 150 r / min, after the drop is completed, warm up to 150-160℃, and react for 5-6 h; a2, after the reaction is completed, cool the reaction liquid to room temperature, then slowly pour it into ice water at a volume ratio of 1:3, a large amount of white solid is precipitated, after standing for 2 h, the solid is collected by suction filtration and washed repeatedly with deionized water until the pH of the washing liquid is 6.9-7.0 to remove sulfuric acid, and finally, the solid is dried at 60℃ under vacuum for 10 h to obtain 1,5-naphthalene disulfonic acid.
[0009] By setting the above technical scheme, naphthalene is used as a starting material, a sulfonic acid group is introduced through a sulfonation reaction, concentrated sulfuric acid is used as a sulfonation reagent, and an electrophilic substitution reaction occurs between the concentrated sulfuric acid and naphthalene to introduce a sulfonic acid group at the 1,5 position of the naphthalene ring to generate 1,5-naphthalene disulfonic acid. During the reaction of concentrated sulfuric acid and naphthalene, the temperature needs to be closely monitored to effectively prevent the occurrence of side reactions caused by excessively high temperature.
[0010] Preferably, the preparation method of the urethane is as follows: b1. 150 g of ethanol, 100 g of urea and 5 g of zinc oxide are added to a high-pressure reaction kettle, which is sealed and stirred at a speed of 400 r / min, and then heated to 170 ℃, and maintained at a pressure of 0.7 MPa for 4 h; b2. After the reaction is completed, the reaction liquid is cooled to room temperature, and the zinc oxide is removed by filtration. The filtrate is subjected to vacuum distillation, and the excess ethanol is recovered at 40 ℃ / 15 mmHg. The remaining material is added to a recrystallization solvent in a volume ratio of 1:2 for recrystallization to obtain urethane crystals.
[0011] By setting the above technical scheme, the catalyst is zinc oxide, which can reduce the activation energy of the reaction and promote the reaction. During the reaction, urea decomposes to produce amino and carbon dioxide, and the amino group undergoes a nucleophilic substitution reaction with ethanol to form urethane.
[0012] Preferably, the reaction solvent is N,N-dimethylformamide or N-methylpyrrolidone.
[0013] Preferably, the preparation method of cetyltrimethylammonium bromide is as follows: c1. 120 g of a 30% mass fraction of trimethylamine aqueous solution and 200 mL of deionized water are added to a four-necked flask, which is stirred at a speed of 300 r / min, and 150 g of 1-bromohexadecane is slowly added dropwise while maintaining the system temperature at 20-25 ℃. After the addition is completed, the temperature is raised to 60 ℃, and the reaction is carried out for 8-9 h; c2. After the reaction is completed, the reaction liquid is cooled to room temperature, and white solids are precipitated. The solids are collected by suction filtration, washed with a small amount of anhydrous ethanol to remove impurities, and then dried at 50 ℃ under vacuum for 6 h to obtain cetyltrimethylammonium bromide.
[0014] By setting the above technical scheme, the nitrogen atom in trimethylamine has a lone pair of electrons, which attacks the carbon atom in 1-bromohexadecane to form cetyltrimethylammonium bromide.
[0015] The application also discloses a preparation process of 1,5-naphthalene diisocyanate, which comprises the following steps: S1, in a four-port flask with a stirrer, a thermometer, a reflux condenser, 1,5-naphthalene disulfonic acid derivative, nitrogen source / carbonyl precursor, phase transfer catalyst and reaction solvent are added, the oil bath temperature is controlled at 115-117 DEG C, and the reaction is stirred at a speed of 400 r / min for 5h; S2, the reaction liquid is transferred to a vacuum distillation device, the oil pump is used to evacuate to a vacuum degree of 4Pa, the pressure is controlled at 3mmHg, and the temperature is slowly raised to 160 DEG C, and the fraction of 140-150 DEG C is collected, which is 1,5-naphthalene diisocyanate crude product; S3, the collected 1,5-naphthalene diisocyanate crude product is recrystallized with ethyl acetate-n-hexane as the recrystallization solvent, the recrystallization solvent and the 1,5-naphthalene diisocyanate crude product are mixed at a volume ratio of 6:1, heated to boiling to completely dissolve the solid, and then slowly cooled to 5 DEG C at a rate of 5 DEG C / h, and 1,5-naphthalene diisocyanate crystals are gradually precipitated; S4, the 1,5-naphthalene diisocyanate crystals are transferred to a vacuum drying oven and dried at 60 DEG C and 10Pa for 4h to obtain 1,5-naphthalene diisocyanate crystals.
[0016] By setting the above technical scheme, the oil bath temperature in S1 is controlled at 115-117 DEG C, which can ensure that the decomposition rate of ethyl carbamate is moderate and the amidation reaction can proceed smoothly, and avoid the occurrence of side reactions caused by high temperature. The stirring speed is 400 r / min, which can ensure that the gas-liquid-solid three-phase (phase transfer catalyst not dissolved) in the reaction system can be fully mixed and uniform, effectively preventing local overheating or uneven concentration of reactants, so that the reaction can be carried out efficiently in a uniform environment. In S2, the reaction liquid is transferred to a vacuum distillation device, the oil pump is used to evacuate to a vacuum degree of 4Pa, the pressure is controlled at 3mmHg, and the temperature is slowly raised to 160 DEG C, and the fraction of 140-150 DEG C is collected, which is 1,5-naphthalene diisocyanate crude product;
[0017] Preferably, in step S2, after the reaction liquid is transferred to the vacuum distillation device, high-purity nitrogen gas is introduced at a flow rate of 50mL / min.
[0018] By setting the above technical scheme, during the reaction process, high-purity nitrogen gas is introduced at a flow rate of 50mL / min. Nitrogen gas, as an inert gas, can remove oxygen in the reaction system, prevent 1,5-naphthalene diisocyanate from being oxidized, and thus ensure the color and purity of the product.
[0019] Preferably, in step S3, the recrystallization solvent is composed of ethyl acetate and n-hexane at a volume ratio of 1:3.
[0020] The beneficial effects of the present application are: 1,5-naphthalene disulfonic acid derivatives can provide naphthalene ring skeleton, and the sulfonic acid groups thereof can be substituted in subsequent reactions to provide the basis for constructing the structure of 1,5-naphthalene diisocyanate; the strong electron-withdrawing effect of the sulfonic acid groups reduces the electron cloud density of the naphthalene ring, which is conducive to the attack of nucleophiles, and the acidity thereof can play a certain proton transfer role in the reaction system. The decomposition of ethyl carbamate or butyl carbamate produces amino and carbon dioxide, and the amino as a nucleophile reacts with the sulfonic acid groups in the 1,5-naphthalene disulfonic acid derivatives to gradually construct the isocyanate group structure; the production of carbon dioxide helps to maintain the weak acidic environment of the reaction system, promoting the reaction to proceed. Cetyltrimethylammonium bromide or dodecyltrimethylammonium chloride as a phase transfer catalyst, the long-chain alkyl group thereof has lipophilicity and can interact with the organic phase, while the quaternary ammonium cation part has hydrophilicity and can combine with ions in the aqueous phase. In the reaction system, it can transfer the reactants or catalysts in the aqueous phase to the organic phase, so that the reactants originally in different phases can fully contact, greatly improving the reaction rate. N,N-dimethylformamide or N-methyl pyrrolidone has a high dielectric constant and good solubility for ionic and polar compounds. In the reaction, it can dissolve 1,5-naphthalene disulfonic acid, ethyl carbamate and various intermediates generated during the reaction, forming a uniform reaction system, so that the molecules of the reactants can move freely, increasing the probability of effective collision and thus speeding up the reaction rate; at the same time, the boiling point of the reaction solvent is moderate, which is convenient for subsequent solvent recovery and product separation by distillation.
[0021] Cetyltrimethylammonium bromide can better play a phase transfer role in N,N-dimethylformamide, so that ionic intermediates and reactants in the reaction system can be quickly transferred between different phases. At the same time, the solvation of N,N-dimethylformamide enhances the catalytic activity of the quaternary ammonium salt, accelerates the decomposition rate of ethyl carbamate, and greatly promotes the entire reaction process.
[0022] The long-chain alkyl group of cetyltrimethylammonium bromide has a hydrophobic interaction with the naphthalene ring of 1,5-naphthalene disulfonic acid, which enables the catalyst to be close to the reaction site, increases the local concentration of the catalyst in the reaction area, increases the effective collision frequency, and thus improves the reaction efficiency. DETAILED DESCRIPTION
[0023] To make the purposes, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be described clearly and completely below in conjunction with the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative labor fall within the scope of protection of the present application.
[0024] Example 1: This example discloses a 1,5-naphthalene diisocyanate, the constituent components of the 1,5-naphthalene diisocyanate include the following weights of raw materials: 1,5-naphthalene disulfonic acid derivative 40 g, nitrogen source / carbonyl precursor 25 g, phase transfer catalyst 3 g, and reaction solvent 600 mL.
[0025] The 1,5-naphthalene disulfonic acid derivative is one of 1,5-naphthalene disulfonic acid or 1,5-naphthalene disulfonic acid disodium salt, the nitrogen source / carbonyl precursor is one of ethyl carbamate or butyl carbamate, the phase transfer catalyst is one of cetyltrimethylammonium bromide or dodecyltrimethylammonium chloride, and the reaction solvent is N,N-dimethylformamide.
[0026] The 1,5-naphthalene disulfonic acid derivative is taken as an example of 1,5-naphthalene disulfonic acid, and the preparation method is as follows: a1, take 100 g of naphthalene and add it to a four-necked flask, slowly drop 260 g of 98% concentrated sulfuric acid while stirring at a speed of 150 r / min, after the drop is completed, increase the temperature to 150°C, and react for 5 h; a2, after the reaction is completed, cool the reaction liquid to room temperature, then slowly pour it into ice water at a volume ratio of 1:3, a large amount of white solid is precipitated, after standing for 2 h, the solid is collected by suction filtration, and the solid is repeatedly washed with deionized water until the pH of the washing liquid is 6.9-7.0 to remove sulfuric acid, finally, the solid is dried at 60°C under vacuum for 10 h to obtain 1,5-naphthalene disulfonic acid.
[0027] The nitrogen source / carbonyl precursor is taken as an example of ethyl carbamate, and the preparation method is as follows: b1, take 150 g of ethanol, 100 g of urea, and 5 g of zinc oxide into a high-pressure reaction kettle, seal it, stir at a speed of 400 r / min, increase the temperature to 170°C, maintain a pressure of 0.7 MPa, and react for 4 h; b2, after the reaction is completed, cool the reaction liquid to room temperature, remove the zinc oxide by filtration, and distill the filtrate under reduced pressure, recover the excess ethanol at 40°C / 15 mmHg, and add the remaining material to a recrystallization solvent at a volume ratio of 1:2 to recrystallize to obtain ethyl carbamate crystals.
[0028] The phase transfer catalyst is taken as an example of cetyltrimethylammonium bromide, and the preparation method is as follows: c1, take 120 g of 30% mass fraction trimethylamine aqueous solution and 200 mL of deionized water into a four-necked flask, stir at a speed of 300 r / min, slowly drop 150 g of 1-bromohexadecane while keeping the system temperature at 20°C, after the drop is completed, increase the temperature to 60°C and react for 8 h; C2, after the reaction, the reaction liquid is cooled to room temperature, precipitate white solid, suction filtration, collection of solids, washed with a small amount of anhydrous ethanol to remove impurities, then washed with the solid at 50 DEG C under vacuum drying 6h, get hexadecyl trimethyl ammonium bromide.
[0029] The embodiment also discloses a preparation process of 1,5-naphthalene diisocyanate, which comprises the following steps: S1, in a four-necked flask with stirrer, thermometer, reflux condenser, 1,5-naphthalene disulfonic acid derivative, nitrogen source / carbonyl precursor, phase transfer catalyst and reaction solvent are added, the temperature of oil bath is controlled at 115 DEG C, and the reaction is stirred at a speed of 400 r / min for 5h; S2, the reaction liquid is transferred to a vacuum distillation device, high-purity nitrogen is introduced at a flow rate of 50mL / min, and an oil pump is used to evacuate to a vacuum degree of 4Pa, the pressure is controlled at 3mmHg, and the temperature is slowly increased to 160 DEG C, and the fraction collected at 140 DEG C is 1,5-naphthalene diisocyanate crude product; S3, the collected 1,5-naphthalene diisocyanate crude product is mixed with ethyl acetate-n-hexane as recrystallization solvent, the recrystallization solvent and 1,5-naphthalene diisocyanate crude product are mixed at a volume ratio of 6:1, heated to boiling to make the solid completely dissolved, then slowly cooled to 5 DEG C at a rate of 5 DEG C / h, and 1,5-naphthalene diisocyanate crystals are gradually precipitated; The recrystallization solvent is composed of ethyl acetate and n-hexane at a volume ratio of 1:3; S4, the 1,5-naphthalene diisocyanate crystals are transferred to a vacuum drying oven, and dried at 60 DEG C and 10Pa for 4h to obtain 1,5-naphthalene diisocyanate crystals.
[0030] Embodiment 2: The embodiment discloses 1,5-naphthalene diisocyanate, and the composition of 1,5-naphthalene diisocyanate comprises the following raw materials in the following weight: 1,5-naphthalene disulfonic acid derivative 60g, nitrogen source / carbonyl precursor 35g, phase transfer catalyst 7g and reaction solvent 900mL.
[0031] The 1,5-naphthalene disulfonic acid derivative is one of 1,5-naphthalene disulfonic acid or 1,5-naphthalene disulfonic acid disodium salt, the nitrogen source / carbonyl precursor is one of ethyl carbamate or butyl carbamate, the phase transfer catalyst is one of hexadecyl trimethyl ammonium bromide or dodecyl trimethyl ammonium chloride, and the reaction solvent is N-methyl pyrrolidone.
[0032] The 1,5-naphthalene disulfonic acid derivative is taken as an example, and the preparation method is as follows: a1, take 100 g of naphthalene into a four-necked flask, slowly add 260 g of 98% concentrated sulfuric acid while stirring at 150 r / min, after the addition, raise the temperature to 160 °C and react for 6 h; a2, after the reaction, cool the reaction liquid to room temperature, then slowly pour it into ice water at a volume ratio of 1:3, a large amount of white solid is precipitated, after standing for 2 h, filter and collect the solid, wash the solid with deionized water repeatedly until the pH of the washing liquid is 7.0 to remove sulfuric acid, finally, dry the solid at 60 °C under vacuum for 10 h to obtain 1,5-naphthalene disulfonic acid.
[0033] The nitrogen source / carbonyl precursor is taken as an example of ethyl carbamate, and the preparation method is as follows: b1, take 150 g of ethanol, 100 g of urea and 5 g of zinc oxide into a high-pressure reaction kettle, seal and stir at 400 r / min, raise the temperature to 170 °C and maintain a pressure of 0.7 MPa for 4 h; b2, after the reaction, cool the reaction liquid to room temperature, remove the zinc oxide by filtration, distill the filtrate under reduced pressure, recover the excess ethanol at 40 °C / 15 mmHg, and recrystallize the remaining material in a recrystallization solvent at a volume ratio of 1:2 to obtain ethyl carbamate crystals.
[0034] The phase transfer catalyst is taken as an example of cetyltrimethylammonium bromide, and the preparation method is as follows: c1, take 120 g of 30% trimethylamine aqueous solution and 200 mL of deionized water into a four-necked flask, stir at 300 r / min, slowly add 150 g of 1-bromohexadecane, keep the system temperature at 25 °C, after the addition, raise the temperature to 60 °C and react for 9 h; c2, after the reaction, cool the reaction liquid to room temperature, precipitate white solid, filter and collect the solid, wash the solid with a small amount of anhydrous ethanol to remove impurities, then dry the washed solid under vacuum at 50 °C for 6 h to obtain cetyltrimethylammonium bromide.
[0035] The embodiment also discloses a preparation process of 1,5-naphthalene diisocyanate, which comprises the following steps: S1, add 1,5-naphthalene disulfonic acid derivative, nitrogen source / carbonyl precursor, phase transfer catalyst and reaction solvent into a four-necked flask with a stirrer, thermometer and reflux condenser, control the temperature of the oil bath at 117 °C, and stir at 400 r / min for 5 h; S2, transfer the reaction liquid to a vacuum distillation device, pass high-purity nitrogen gas at 50 mL / min, and use an oil pump to evacuate to a vacuum degree of 4 Pa, control the pressure at 3 mmHg, slowly raise the temperature to 160 °C, and collect the fraction at 150 °C, which is a crude product of 1,5-naphthalene diisocyanate. S3, the collected 1,5-naphthalene diisocyanate crude product, using ethyl acetate-n-hexane as recrystallization solvent, the recrystallization solvent and 1,5-naphthalene diisocyanate crude product is mixed according to the volume ratio 6:1, heated to boiling to make the solid completely dissolved, then slowly cooled to 5℃ at a rate of 5℃ / h, gradually precipitated 1,5-naphthalene diisocyanate crystals; Wherein, the recrystallization solvent is composed of ethyl acetate and n-hexane according to the volume ratio 1:3; S4, the 1,5-naphthalene diisocyanate crystals were transferred to the vacuum drying oven, dried at 60℃, 10Pa for 4h, 1,5-naphthalene diisocyanate crystals were obtained.
[0036] Example 3: this embodiment discloses a kind of 1,5-naphthalene diisocyanate, the composition of 1,5-naphthalene diisocyanate includes the following weight of raw materials: 1,5-naphthalene disulfonic acid derivative 50g, nitrogen source / carbonyl precursor 30g, phase transfer catalyst 5g and reaction solvent 750mL.
[0037] 1,5-naphthalene disulfonic acid derivative is one of 1,5-naphthalene disulfonic acid or 1,5-naphthalene disulfonic acid disodium salt, nitrogen source / carbonyl precursor is one of ethyl carbamate or butyl carbamate, phase transfer catalyst is one of cetyltrimethylammonium bromide or dodecyltrimethylammonium chloride, and reaction solvent is N,N-dimethylformamide.
[0038] 1,5-naphthalene disulfonic acid derivative is taken as an example, and its preparation method is as follows: a1, take 100g naphthalene and add it into four-necked flask, slowly drop 260g of 98% sulfuric acid, while stirring at 150r / min, after dropping, heat to 155℃, and react for 5.5h; a2, after reaction, the reaction liquid is cooled to room temperature, then slowly pour into ice water according to the volume ratio 1:3, a large amount of white solid is precipitated, after standing for 2h, the solid is collected by suction filtration, and the solid is washed repeatedly with deionized water until the pH of the washing liquid is 6.9-7.0 to remove sulfuric acid, finally, the solid is dried at 60℃ under vacuum for 10h to obtain 1,5-naphthalene disulfonic acid.
[0039] Nitrogen source / carbonyl precursor is taken as an example, and its preparation method is as follows: b1, take 150g ethanol, 100g urea and 5g zinc oxide into high-pressure reaction kettle, seal, stir at 400r / min, heat to 170℃, maintain 0.7MPa pressure for 4h; b2、After the reaction is completed, the reaction solution is cooled to room temperature, and zinc oxide is removed by filtration. The filtrate is distilled under reduced pressure, and the excess ethanol is recovered at 40℃ / 15mmHg. The remaining material is added to a recrystallization solvent in a volume ratio of 1:2 for recrystallization to obtain ethyl carbamate crystals.
[0040] The phase transfer catalyst is cetyltrimethylammonium bromide, and its preparation method is as follows: c1、120g of 30% trimethylamine aqueous solution and 200mL of deionized water are added to a four-necked flask, stirred at a speed of 300r / min, and 150g of 1-bromohexadecane is slowly added while keeping the system temperature at 22℃. After the addition is completed, the temperature is raised to 60℃ and reacted for 8.5h; c2、After the reaction is completed, the reaction solution is cooled to room temperature, and white solids are precipitated. The solids are collected by suction filtration, washed with a small amount of anhydrous ethanol to remove impurities, and then the washed solids are dried at 50℃ under vacuum for 6h to obtain cetyltrimethylammonium bromide.
[0041] The embodiment also discloses a preparation process of 1,5-naphthalene diisocyanate, which comprises the following steps: S1、A four-necked flask with a stirrer, a thermometer, and a reflux condenser is added with 1,5-naphthalene disulfonic acid derivative, nitrogen source / carbonyl precursor, phase transfer catalyst, and reaction solvent. The temperature is controlled by an oil bath at 116℃, and the reaction is stirred at a speed of 400r / min for 5h; S2、The reaction solution is transferred to a vacuum distillation device, high-purity nitrogen gas is introduced at a flow rate of 50mL / min, and an oil pump is used to evacuate to a vacuum degree of 4Pa. The pressure is controlled at 3mmHg, and the temperature is slowly raised to 160℃. The fraction collected at 145℃ is the crude 1,5-naphthalene diisocyanate; S3、The collected crude 1,5-naphthalene diisocyanate is mixed with ethyl acetate-n-hexane as a recrystallization solvent in a volume ratio of 6:1. The recrystallization solvent and the crude 1,5-naphthalene diisocyanate are heated to boiling to completely dissolve the solids. Then, the temperature is slowly cooled to 5℃ at a rate of 5℃ / h, and 1,5-naphthalene diisocyanate crystals are gradually precipitated; The recrystallization solvent is composed of ethyl acetate and n-hexane in a volume ratio of 1:3; S4、The 1,5-naphthalene diisocyanate crystals are transferred to a vacuum drying oven and dried at 60℃ and 10Pa for 4h to obtain 1,5-naphthalene diisocyanate crystals.
[0042] Comparative Example 1: A 1,5-naphthalene diisocyanate is prepared, which is different from the embodiment 3 only in that cetyltrimethylammonium bromide is not added, but an equal proportion of tetrabutylammonium hydrogen sulfate is added (to compare the influence of different quaternary ammonium salt structures).
[0043] Comparative Example 2: A 1,5-naphthalene diisocyanate, the difference between which and Example 3 is only that N,N-dimethylformamide is not added, and is replaced by an equal proportion of dimethyl sulfoxide (comparing the effects of different aprotic polar solvents).
[0044] Comparative Example 3: A 1,5-naphthalene diisocyanate, the difference between which and Example 3 is only that ethyl carbamate is not added, and is replaced by an equal proportion of urea (comparing the differences in nitrogen source form and carbonyl precursors).
[0045] Comparative Example 4: A 1,5-naphthalene diisocyanate, the difference between which and Example 3 is only that 1,5-naphthalene disulfonic acid is not added, and is replaced by an equal proportion of 1,8-naphthalene disulfonic acid (comparing the effects of spatial steric hindrance of sulfonic acid groups).
[0046] Comparative Example 5: A 1,5-naphthalene diisocyanate, the difference between which and Example 3 is only that nitrogen is not passed in S2 for the preparation of 1,5-naphthalene diisocyanate, and is replaced by reaction under an air atmosphere (comparing the effects of oxidation on the product).
[0047] The products obtained in Examples 1-3 and Comparative Examples 1-5 above were subjected to performance testing, and the comprehensive performance of the final product was measured, and the results are shown in Table 1.
[0048] Table 1 Performance parameters of YY obtained in Examples 1-3 and Comparative Examples 1-5
[0049] Among them, the qualified standards for the target product 1,5-naphthalene diisocyanate are as follows: hydrolyzable chlorine <100 PPM, NCO content 40.0-40.5%, melting point 127.0-130.0°C, appearance: white flaky solid. It can be seen from Table 1 that the various indicators of the 1,5-naphthalene diisocyanate obtained by the present application all meet the requirements.
[0050] The above examples are only used to illustrate the technical solutions of the present application, and not to limit them; although the present application has been described in detail with reference to the foregoing examples, those skilled in the art should understand that they can still modify the technical solutions described in the foregoing examples, or make equivalent substitutions for part of the technical features; and these modifications or substitutions do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application.
Claims
1. A 1,5-naphthalene diisocyanate, characterized in that The composition of 1,5-naphthalene diisocyanate includes the following raw materials by weight: 40-60 g of a 1,5-naphthalene disulfonic acid derivative, 25-35 g of a nitrogen source / carbonyl precursor, 3-7 g of a phase transfer catalyst and 600-900 mL of a reaction solvent.
2. 1,5-naphthalene diisocyanate according to claim 1, characterized in that The composition of 1,5-naphthalene diisocyanate includes the following raw materials by weight: 50 g of a 1,5-naphthalene disulfonic acid derivative, 30 g of a nitrogen source / carbonyl precursor, 5 g of a phase transfer catalyst, and 750 mL of a reaction solvent.
3. 1,5-naphthalene diisocyanate according to claim 1 or 2, characterized in that The 1,5-naphthalene disulfonic acid derivative is one of 1,5-naphthalene disulfonic acid or 1,5-naphthalene disulfonic acid disodium salt, the nitrogen source / carbonyl precursor is one of ethyl carbamate or butyl carbamate, and the phase transfer catalyst is one of hexadecyltrimethylammonium bromide or dodecyltrimethylammonium chloride.
4. 1,5-naphthalene diisocyanate according to claim 3, characterized in that The preparation method of 1,5-naphthalene disulfonic acid is as follows: a1. Take 100g of naphthalene and add it to a four-necked flask. Slowly add 260g of 98% concentrated sulfuric acid dropwise while stirring at a speed of 150r / min. After the addition is complete, heat to 150-160℃ and react for 5-6h. a2. After the reaction is completed, the reaction solution is cooled to room temperature and then slowly poured into ice water at a volume ratio of 1:3 to precipitate a large amount of white solid. After standing for 2 hours, the solid is filtered and collected. The solid is repeatedly washed with deionized water to a pH of 6.9-7.0 to remove sulfuric acid. Finally, the solid is vacuum dried at 60°C for 10 hours to obtain 1,5-naphthalene disulfonic acid.
5. 1,5-naphthalene diisocyanate according to claim 3, characterized in that The preparation method of ethyl carbamate is as follows: b1. Add 150g of ethanol, 100g of urea and 5g of zinc oxide into an autoclave, seal it, stir at 400r / min, heat to 170°C, maintain the pressure at 0.7MPa and react for 4h. b2. After the reaction is completed, the reaction solution is cooled to room temperature, zinc oxide is removed by filtration, and the filtrate is subjected to reduced pressure distillation. Excess ethanol is recovered under the conditions of 40°C / 15 mmHg, and the remaining material is added with a recrystallization solvent at a volume ratio of 1:2 for recrystallization to obtain ethyl carbamate crystals.
6. 1,5-naphthalene diisocyanate according to claim 5, characterized in that The reaction solvent is N,N-dimethylformamide or N-methylpyrrolidone.
7. 1,5-naphthalene diisocyanate according to claim 3, characterized in that The preparation method of hexadecyltrimethylammonium bromide is as follows: c1. Add 120 g of a 30% trimethylamine aqueous solution and 200 mL of deionized water to a four-necked flask, stir at 300 r / min, and slowly add 150 g of 1-bromohexadecane dropwise. Maintain the system temperature at 20-25°C. After the addition is complete, heat to 60°C and react for 8-9 hours. c2. After the reaction is completed, the reaction solution is cooled to room temperature to precipitate a white solid, which is filtered and collected. The solid is washed with a small amount of anhydrous ethanol to remove impurities, and then the washed solid is vacuum-dried at 50°C for 6 hours to obtain hexadecyltrimethylammonium bromide.
8. A process for preparing 1,5-naphthalene diisocyanate according to any one of claims 1 to 7, characterized in that: The preparation process includes the following steps: S1. Add 1,5-naphthalene disulfonic acid derivative, nitrogen source / carbonyl precursor, phase transfer catalyst and reaction solvent to a four-necked flask equipped with a stirrer, thermometer and reflux condenser. Control the temperature of the oil bath at 115-117°C and stir at 400 r / min for 5 h. S2. Transfer the reaction solution to a vacuum distillation apparatus, evacuate to a vacuum degree of 4 Pa using an oil pump, control the pressure to 3 mmHg, slowly raise the temperature to 160°C, and collect the fraction at 140-150°C, which is the crude 1,5-naphthalene diisocyanate; S3. The collected crude 1,5-naphthalene diisocyanate was recrystallized using ethyl acetate-n-hexane as a solvent. The recrystallization solvent and the crude 1,5-naphthalene diisocyanate were mixed in a volume ratio of 6:1, and the mixture was heated until the solvent boiled to completely dissolve the solid. The mixture was then slowly cooled to 5°C at a rate of 5°C / h to gradually precipitate 1,5-naphthalene diisocyanate crystals. S4. Transfer the 1,5-naphthalene diisocyanate crystals to a vacuum drying oven and dry them at 60° C. and 10 Pa for 4 h to obtain 1,5-naphthalene diisocyanate crystals.
9. The process for preparing 1,5-naphthalene diisocyanate according to claim 8, wherein: In step S2, the reaction solution was transferred to a vacuum distillation apparatus and high-purity nitrogen was introduced at 50 mL / min.
10. The process for preparing 1,5-naphthalene diisocyanate according to claim 8, wherein: In step S3, the recrystallization solvent consists of ethyl acetate and n-hexane in a volume ratio of 1:3.