A method for solvent-free synthesis of aromatic diamide nucleating agent

Abstract

The application relates to the technical field of synthesis of aromatic diamide nucleating agents, and specifically provides a method for synthesizing an aromatic diamide nucleating agent without solvent. The method comprises the following steps: firstly, uniformly mixing a compound of formula (I) and an acyl halide reagent, and then adding a nitrogen atom-containing organic base catalyst; secondly, carrying out an acyl chloride reaction at 50-100 DEG C to obtain a compound of formula (II); and thirdly, grinding the compound of formula (II) and an organic primary amine compound at 20-100 DEG C to make the compound of formula (II) and the organic primary amine compound undergo an amidation reaction, so as to obtain an aromatic diamide nucleating agent as shown in formula (III). The aromatic diamide nucleating agent is synthesized without solvent, the use of a large amount of solvent is avoided, the yield and purity of the final product, the aromatic diamide nucleating agent, are high, the synthesis process flow is simplified, the method is suitable for industrial amplification and production, and has a positive effect on the practical application of the aromatic diamide nucleating agent.

Description

Technical Field

[0001] This application relates to the technical field of synthesizing aromatic diamide nucleating agents, and specifically provides a solventless method for synthesizing aromatic diamide nucleating agents. Background Technology

[0002] Nucleating agents are novel functional additives suitable for incompletely crystalline plastics such as polyethylene and polypropylene. They alter the resin's crystallization behavior, accelerating the crystallization rate, increasing crystal density, and promoting finer grain size. This results in shorter molding cycles and improved physical and mechanical properties of the products, including transparency, surface gloss, tensile strength, rigidity, heat distortion temperature, impact resistance, and creep resistance. For polypropylene, its advantages—low specific gravity, high tensile yield strength, flexural modulus, hardness, and good resistance to environmental stress cracking—along with abundant and inexpensive raw materials, make it ideal for injection molding. However, polypropylene is a crystalline polymer with large spherulites, resulting in low impact strength and significant post-shrinkage in the finished product, hindering its use in injection molding. Adding nucleating agents generates microcrystalline polypropylene, modifying the resin and achieving higher performance. Adding nucleating agents to polypropylene effectively promotes the crystallization process and accelerates the crystallization rate, giving the molecules a microcrystalline structure. This not only improves the product's impact strength and yield strength but also enhances its appearance, shortens the injection cycle, and increases productivity. With the development of new polypropylene products and grades, nucleating agents will be more widely used in various fields of polypropylene product development. Based on different nucleation mechanisms, nucleating agents are mainly classified into two types: α-nucleating agents and β-nucleating agents. In recent research and development, aromatic diamide nucleating agents are considered to be a type of nucleating agent with high nucleation efficiency.

[0003] Currently, the main methods for synthesizing aromatic diamide nucleating agents are: using aromatic dicarboxylic acids and organic amines as raw materials, and triphenylphosphine and pyridine as catalysts, and... N The reaction was carried out at 100°C using methylpyrrolidone as a solvent, followed by treatment with isopropanol-water to obtain the product. The drawbacks of this process are as follows: (1) The cost of the catalyst triphenylphosphine is high, and the amount used is large; the generated triphenylphosphine oxide is difficult to separate and utilize; (2) The raw material aromatic dicarboxylic acid has poor solubility, thus requiring a large amount of expensive catalyst. N (3) The reaction post-processing uses a large amount of isopropanol-water, which is difficult to separate and recover; (4) The reaction operation is complicated and the purity of the product cannot be guaranteed.

[0004] In view of the poor solubility of raw materials, intermediates and products in solvents in the preparation process of nucleating agents, the existing process often uses a large amount of special solvent to dissolve the materials, and the use amount of reaction solvents and post-processing solvents often reaches dozens to more than one hundred times of the amount of raw materials. After the reaction is completed, long and complicated post-processing operation is needed to remove the solvents, and then the product can be separated and purified to achieve the desired purity. Due to the use of a large amount of solvents in the synthesis process of such nucleating agents, the volume of reaction materials is large, the post-processing is complicated, the post-processing time is long, and other disadvantages, which leads to the need to use more and larger reaction equipment for industrial scale production, the operation time is long, the energy consumption is high, the requirement for solvent recovery equipment is high, and it also has a certain impact on the production environment. Due to the large cost of solvents, equipment, labor and environmental protection, the product cost is high, the yield is limited, which affects the practical application of such nucleating agents. SUMMARY

[0005] In view of this, the present application provides a method for synthesizing aromatic diamide nucleating agent without solvent, which comprises the following steps:

[0006]

[0007] In step S1, the compound of formula (I) and the acyl halide reagent are mixed uniformly, and then the nitrogen-containing organic base catalyst is added. Then, the acyl chloride reaction occurs at 50-100°C to obtain the compound of formula (II). The molar ratio of the compound of formula (I), the acyl halide reagent and the organic base catalyst is 1:(2.0-20.0):(0.05-2.0). The organic base catalyst includes pyridine organic base catalyst and non-pyridine organic base catalyst with a molar ratio of 1:(0.1-0.3).

[0008] In step S2, the compound of formula (II) and the organic primary amine compound are ground at 20-100°C to occur amidation reaction to obtain the aromatic diamide nucleating agent as shown in formula (III).

[0009] wherein R1 is independently selected from unsubstituted or substituted C5-C10 alkyl or unsubstituted or substituted C5-C10 aromatic group; the substituent in the substituted C5-C10 alkyl is selected from C1-C3 alkoxy, C2-C3 alkenyl, C2-C3 alkynyl or halogen; the substituent in the substituted C5-C10 aromatic group is selected from C1-C3 alkyl, C1-C3 alkoxy or halogen; the molar ratio of the compound of formula (II) and the organic primary amine compound is 1:(4.0-10.0).

[0010] wherein the structure of the organic primary amine compound is wherein R1 is defined as above.

[0011] In some alternative embodiments, the molar ratio of the compound of formula (I), the acyl halide reagent, and the organic base catalyst is 1 : (5.0-15.0): (0.1-0.5). The molar ratio of the compound of formula (I) and the acyl halide reagent can be 1 :5.0, 1 :5.5, 1 :6.0, 1 :6.5, 1 :7.0, 1 :7.1, 1 :7.2, 1 :7.3, 1 :7.4, 1 :7.5, 1 :7.6, 1 :7.7, 1 :7.8, 1 :7.9, 1 :8.0, 1 :8.1, 1 :8.2, 1 :8.3, 1 :8.4, 1 :8.5, 1 :8.6, 1 :8.7, 1 :8.8, 1 :8.9, 1 :9.0, 1 :9.1, 1 :9.2, 1 :9.3, 1 :9.4, 1 :9.5, 1 :9.6, 1 :9.7, 1 :9.8, 1 :9.9, 1 :10.0, 1 :10.1, 1 :10.2, 1 :10.3, 1 :10.4, 1 :10.5, 1 :10.6, 1 :10.7, 1 :10.8, 1 :10.9, 1 :11.0, 1 :11.5, 1 :12.0, 1 :12.5, 1 :13.0, 1 :13.5, 1 :14.0, 1 :14.5, or 1 :15.0, etc. The molar ratio of the compound of formula (I) and the organic base catalyst can be 1 :0.1, 1 :0.2, 1 :0.3, 1 :0.4, or 1 :0.5, etc.

[0012] In some alternative embodiments, the molar ratio of the compound of formula (II) and the organic primary amine compound is 1 : (4.0-5.0). The molar ratio of the compound of formula (II) and the organic primary amine compound can be 1 :4.0, 1 :4.1, 1 :4.2, 1 :4.3, 1 :4.4, 1 :4.5, 1 :4.6, 1 :4.7, 1 :4.8, 1 :4.9, or 1 :5.0, etc.

[0013] In some alternative embodiments, the organic base catalyst comprises a pyridine organic base catalyst and a non-pyridine organic base catalyst in a molar ratio of 1 : (0.15-0.25); for example, 1 :0.15, 1 :0.16, 1 :0.17, 1 :0.18, 1 :0.19, 1 :0.2, 1 :0.21, 1 :0.22, 1 :0.23, 1 :0.23, or 1 :0.25, etc.

[0014] In some alternative embodiments, the pyridine-based organic base catalyst includes at least one of pyridine (abbreviated as Py, CAS No. 110-86-1), 2,3-dimethylpyridine (CAS No. 1122-58-3), 2,3-dimethylpyridine (CAS No. 583-61-9), 2,4-dimethylpyridine (CAS No. 108-47-4), 2,5-dimethylpyridine (CAS No. 589-93-5), 2,6-dimethylpyridine (CAS No. 108-48-5), 3,4-dimethylpyridine (CAS No. 583-58-4), or 3,5-dimethylpyridine (CAS No. 591-22-0).

[0015] In some specific embodiments, the pyridine-based organic base catalyst is selected from pyridine.

[0016] In some alternative embodiments, the non-pyridine organic base catalyst includes at least one of triethylamine (CAS No. 121-44-8), tripropylamine (CAS No. 102-69-2), N,N-dimethylformamide (CAS No. 68-12-2), or N,N-dimethylacetamide (CAS No. 127-19-5).

[0017] In some alternative embodiments, the non-pyridine organic base catalyst comprises triethylamine and N,N-dimethylacetamide. In other alternative embodiments, the non-pyridine organic base catalyst comprises triethylamine and N,N-dimethylacetamide in a molar ratio of 1:(0.3–0.5); for example, 1:0.3, 1:0.31, 1:0.32, 1:0.33, 1:0.34, 1:0.35, 1:0.36, 1:0.37, 1:0.38, 1:0.39, 1:0.4, 1:0.41, 1:0.42, 1:0.43, 1:0.44, 1:0.45, 1:0.46, 1:0.47, 1:0.48, 1:0.49, or 1:0.5, etc. In some specific embodiments, the non-pyridine organic base catalyst comprises triethylamine and N,N-dimethylacetamide in a molar ratio of 1:0.4.

[0018] In some alternative embodiments, the compound of formula (I) is selected from 1,5-naphthalenedicarboxylic acid (Naphthalenedicarboxylic acid). CAS number 7315-96-0), 1,6-naphthalenedicarboxylic acid ( ), 1,7-naphthalenedicarboxylic acid ( ), 1,8-naphthalenedicarboxylic acid ( CAS number 518-05-8), 2,6-naphthalenedicarboxylic acid ( CAS number 1141-38-4), 2,7-naphthalenedicarboxylic acid ( at least one of 1,5-naphthalene dicarboxylic acid, 1,8-naphthalene dicarboxylic acid, 2,6-naphthalene dicarboxylic acid, or 2,7-naphthalene dicarboxylic acid.

[0019] In other optional embodiments, the compound of Formula (I) comprises at least one of 1,5-naphthalene dicarboxylic acid, 1,8-naphthalene dicarboxylic acid, 2,6-naphthalene dicarboxylic acid, or 2,7-naphthalene dicarboxylic acid. In some specific embodiments, the compound of Formula (I) is selected from 1,5-naphthalene dicarboxylic acid. In some specific embodiments, the compound of Formula (I) is selected from 2,6-naphthalene dicarboxylic acid. In some specific embodiments, the compound of Formula (I) is selected from 2,7-naphthalene dicarboxylic acid.

[0020] In some optional embodiments, the acyl halogenating reagent comprises at least one of a halogenated sulfoxide (e.g., sulfurous acid chloride, etc.) or a phosphorus trihalide (e.g., phosphorus trichloride). In other optional embodiments, the acyl halogenating reagent comprises at least one of dichlorosulfoxide or dibromosulfoxide. In some specific embodiments, the acyl halogenating reagent is selected from dichlorosulfoxide.

[0021] In some optional embodiments, R1is independently selected from .

[0022] In other optional embodiments, R1is independently selected from , or . In some specific embodiments, R1is selected from . In some specific embodiments, R1is selected from . In some specific embodiments, R1is selected from .

[0023] In some alternative embodiments, the organic tertiary amine compound includes 1,1,1-trimethylamine (CAS No. 121-60-8), 1,1,2-trimethylamine (CAS No. 109-55-7), 1,1,3-trimethylamine (CAS No. 676-55-7), 1,2,2-trimethylamine (CAS No. 676-55-7), 1,2,3-trimethylamine (CAS No. 676-55-7), 1,3,3-trimethylamine (CAS No. 676-55-7), 2,2,2-trimethylamine (CAS No. 16591-71-2), 2,2,3-trimethylamine (CAS No. 676-55-7), 2,3,3-trimethylamine (CAS No. 676-55-7), 3,3,3-trimethylamine (CAS No. 676-55-7), 1,1,1,2-trimethylamine (CAS No. 676-55-7), 1,1,1,3-trimethylamine (CAS No. 676-55-7), 1,1,2,2-trimethylamine (CAS No. 676-55-7), 1,1,2,3-trimethylamine (CAS No. 676-55-7), 1,1,3,3-trimethylamine (CAS No. 676-55-7), 1,2,2,2-trimethylamine (CAS No. 676-55-7), 1,2,2,3-trimethylamine (CAS No. 676-55-7), 1,2,3,3-trimethylamine (CAS No. 676-55-7), 1,3,3,3-trimethylamine (CAS No. 676-55-7), 2,2,2,2-trimethylamine (CAS No. 676-55-7), 2,2,2,3-trimethylamine (CAS No. 676-55-7), 2,2,3,3-trimethylamine (CAS No. 676-55-7), 2,3,3,3-trimethylamine (CAS No. 676-55-7), 3,3,3,3-trimethylamine (CAS No. 676-55-7), 1,1,1,2,2-trimethylamine (CAS No. 676-55-7), 1,1,1,2,3-trimethylamine (CAS No. 676-55-7), 1,1,1,3,3-trimethylamine (CAS No. 676-55-7), 1,1,2,2,2-trimethylamine (CAS No. 676-55-7), 1,1,2,2,3-trimethylamine (CAS No. 676-55-7), 1,1,2,3,3-trimethylamine (CAS No. 676-55-7), 1,1,3,3,3-trimethylamine (CAS No. 676-55-7), 1,2,2,2,2-trimethylamine (CAS No. 676-55-7), 1,2,2,2,3-trimethylamine (CAS No. 676-55-7), 1,2,2,3,3-trimethylamine (CAS No. 676-55-7), 1,2,3,3,3-trimethylamine (CAS No. 676-55-7), 2,2,2,2,2-trimethylamine (CAS No. 676-55-7), 2,2,2,2,3-trimethylamine (CAS No. 676-55-7), 2,2,2,3,3-trimethylamine (CAS No. 676-55-7), 2,2,3,3,3-trimethylamine (CAS No. 676-55-7), 2,3,3,3,3-trimethylamine (CAS No. 676-55-7), 3,3,3,3,3-trimethylamine (CAS No. 676-55-7), 1,1,1,2,2,2-trimethylamine (CAS No. 676-55-7), 1,1,1,2,2,3-trimethylamine (CAS No. 676-55-7), 1,1,1,2,3,3-trimethylamine (CAS No. 676-55-7), 1,1,1,3,3,3-trimethylamine (CAS No. 676-55-7), 1,1,2,2,2,2-trimethylamine (CAS No. 676-55-7), 1,1,2,2,2,3-trimethylamine (CAS No. 676-55-7), 1,1,2,2,3,3-trimethylamine (CAS No. 676-55-7), 1,1,2,3,3,3-trimethylamine (CAS No. 676-55-7), 1,2,2,2,2,2-trimethylamine (CAS No. 676-55-7), 1,2,2,2,2,3-trimethylamine (CAS No. 676-55-7), 1,2,2,2,3,3-trimethylamine (CAS No. 676-55-7), 1,2,2,3,3,3-trimethylamine (CAS No. 676-55-7), 1,2,3,3,3,3-trimethylamine (CAS No. 676-55-7), 2,2,2,2,2,2-trimethylamine (CAS No. 676-55-7), 2,2,2,2,2,3-trimethylamine (CAS No. 676-55-7), 2,2,2,2,3,3-trimethylamine (CAS No. 676-55-7), 2,2,2,3,3,3-trimethylamine (CAS No. 676-55-7), 2,2,3,3,3,3-trimethylamine (CAS No. 676-55-7), 2,3,3,3,3,3-trimethylamine (CAS No. 676-55-7), 3,3,3,3,3,3-trimethylamine (CAS No. 676-55-7),4-Difluorocycloheptane-1-amine (CAS No. 1461708-43-9), cyclooctylamine (CAS No. 5452-37-9), aniline (CAS No. 62-53-3), 2-methylaniline (CAS No. 95-53-4), 3-methylaniline (CAS No. 108-44-1), 4-methylaniline (CAS No. 106-49-0), 2-fluoroaniline (CAS No. 348-54-9), 3-fluoroaniline (CAS No. 372-19-0), 4-fluoroaniline ...1461708-43-9), cyclooctylamine (CAS No. 5452-37-9), aniline (CAS No. 1461708-43-9), cyclooctylamine (CAS No. 5452-37-9), aniline (CAS No. 1461708-43-9), cyclooctylamine (CAS No. 5452-37-9), aniline (CAS No. 14617 It is at least one of the following: 371-40-4), 2-chloroaniline (CAS No. 95-51-2), 2-bromoaniline (CAS No. 615-36-1), 3-bromoaniline (CAS No. 591-19-5), 2-iodoaniline (CAS No. 615-43-0), 2-bromo-3-chloroaniline (CAS No. 96558-73-5), 4-tert-butyl-3-chloroaniline (CAS No. 52756-36-2), or 2,4-dibromo-3-chloroaniline (CAS No. 80026-15-9).

[0024] In some alternative embodiments, the organic primary amine compound includes at least one selected from cyclopentylamine, cyclohexylamine, or aniline. In some specific embodiments, the organic primary amine compound is selected from cyclopentylamine. In some specific embodiments, the organic primary amine compound is selected from cyclohexylamine. In some specific embodiments, the organic primary amine compound is selected from aniline.

[0025] In some alternative embodiments, the aromatic diamide nucleating agent includes N,N'-dicyclopentyl-1,5-naphthalenediamide (N,N'-dicyclopentyl-1,5-naphthalenediamide). N,N'-Dicyclohexyl-1,5-naphthalenedicarboxamide ( ), N,N'-diphenyl-1,5-naphthalenedicarboxamide ( N,N'-Dicyclopentyl-2,6-naphthalenedicarboxamide ( N,N'-Dicyclohexyl-2,6-naphthalenedicarboxamide ( (CAS number 153250-52-3) or N,N'-diphenyl-2,6-naphthalenedicarboxamide ( At least one of the following. In some specific embodiments, the aromatic diamide nucleating agent is selected from N,N'-dicyclohexyl-2,6-naphthalenediamide.

[0026] In some optional embodiments, in step S1, the reaction temperature of the acyl chloride reaction is 50-80°C; for example, 50°C, 55°C, 60°C, 65°C, 70°C, 75°C, or 80°C.

[0027] In some alternative embodiments, in step S1, the reaction time of the acyl chloride reaction is 2-10 hours; for example, 2 hours, 2.5 hours, 3 hours, 3.5 hours, 4 hours, 4.5 hours, 5 hours, 5.5 hours, 6 hours, 6.5 hours, 7 hours, 7.5 hours, 8 hours, 8.5 hours, 9 hours, 9.5 hours, or 10 hours, etc.

[0028] In some alternative embodiments, in step S2, the reaction temperature of the amidation reaction is 20-70℃; for example, 20℃, 25℃, 30℃, 35℃, 40℃, 45℃, 50℃, 55℃, 60℃, 65℃, or 70℃, etc.

[0029] In some alternative embodiments, in step S2, the reaction time of the amidation reaction is 5-20 hours; for example, 5 hours, 5.5 hours, 6 hours, 6.5 hours, 7 hours, 7.5 hours, 8 hours, 8.5 hours, 9 hours, 9.5 hours, 10 hours, 10.5 hours, 11 hours, 11.5 hours, 12 hours, 12.5 hours, 13 hours, 13.5 hours, 14 hours, 14.5 hours, 15 hours, 15.5 hours, 16 hours, 16.5 hours, 17 hours, 17.5 hours, 18 hours, 18.5 hours, 19 hours, 19.5 hours, or 20 hours, etc.

[0030] The present application has the following beneficial effects:

[0031] First, the present application synthesizes aromatic diamide nucleating agents under solvent-free conditions, avoiding the use of a large amount of solvent, not only making the intermediate compound (II) not need to be separated and purified directly for the next step preparation, but also simplifying the post-treatment of the final product aromatic diamide nucleating agent, and the yield and purity of the final product aromatic diamide nucleating agent are high. Thus, the synthesis process flow is simplified, which is suitable for industrialization and production, and has a positive effect on the practical application of aromatic diamide nucleating agents.

[0032] Second, the method of the present application can effectively reduce the equipment size and the number of equipment, thereby reducing the preparation cost.

[0033] Third, the process operation is green and environmentally friendly, does not use organic solvents, and is friendly to the environment. DETAILED DESCRIPTION

[0034] The present application discloses a method for solvent-free synthesis of aromatic diamide nucleating agent. Those skilled in the art can refer to the content herein and appropriately improve the process parameters to achieve. It is particularly pointed out that all similar substitutions and changes are obvious to those skilled in the art, and they are considered to be included in the present application. The method and application of the present application have been described by preferred embodiments, and the relevant personnel can obviously make changes or appropriate changes and combinations to the methods and applications described herein without departing from the content, spirit and scope of the present application, to realize and apply the technology of the present application.

[0035] In order to make the purpose, technical scheme and advantages of the present application more clear, the present application will be further described in detail below with examples.

[0036] Examples of aromatic diamide nucleating agent:

[0037] In this embodiment, aromatic diamide nucleating agent is taken as N,N'-dicyclohexyl terephthalamide as an example. Specifically, the synthesis route of N,N'-dicyclohexyl terephthalamide is as follows:

[0038]

[0039] Step S1, synthesis of terephthaloyl chloride:

[0040] At room temperature, terephthalic acid and thionyl chloride were added into a 250 mL reaction bottle and stirred uniformly, 1.0 g of organic base catalyst was added dropwise, the temperature was raised to 65°C and stirred at 65°C for 4 hours, and the white solid in the reaction mixture was uniformly dispersed; the excess thionyl chloride was recovered by reduced pressure distillation using a rotary evaporator, and the reduced pressure distillation conditions were 50-65°C / 20 mmHg (36°C when a fraction was distilled out), to obtain a white solid.

[0041] Step S2, synthesis of N,N'-dicyclohexyl terephthalamide:

[0042] At room temperature, the terephthaloyl chloride obtained in step S1 and cyclohexylamine (wherein the molar ratio of terephthaloyl chloride to cyclohexylamine was 1:5.0) were sequentially added into a grinder, the grinder was started, and the reaction was completed after grinding at room temperature for 6 hours. The reaction mixture in the grinder was transferred into a beaker, 50 mL of water was added, and the mixture was stirred and pulped. After filtration, the filter cake was washed with water for pulping 4 times (50 mL each time) and filtration; the filter cake was dried by blowing air at 70 °C for 4 hours, and was crushed to obtain N,N'-dicyclohexyl terephthalamide in the form of white powder.

[0043] The purity of N,N'-dicyclohexylterephthalamide was detected by high performance liquid chromatography (HPLC).

[0044] Table 1, reaction condition selection in step S1 during synthesis of N,N'-dicyclohexylterephthalamide:

[0045]

[0046] Unless otherwise specified, the molecular weight of "terephthalic acid" used in the present application is 203.02; the molecular weight 2 of "thionyl chloride" used in the present application is 118.97; the molecular weight of "pyridine" used in the present application is 79.10; the molecular weight of "triethylamine" used in the present application is 101.19; the molecular weight of "N,N-dimethylacetamide" used in the present application is 87.12; the molecular weight of "terephthaloyl chloride" used in the present application is 203.02; the molecular weight of "N,N'-dicyclohexylterephthalamide" used in the present application is 328.46.

[0047] As can be seen from Table 1, the aromatic diamide nucleating agent is synthesized in the present application under solvent-free conditions, avoiding the use of a large amount of solvent, not only making the intermediate compound (II) not need to be separated and purified directly for use in the next step of preparation, but also simplifying the post-treatment of the final product aromatic diamide nucleating agent, and the final product aromatic diamide nucleating agent has high yield and high purity. Thus, the synthesis process flow is simplified, suitable for industrialization and production, and has a positive effect on the practical application of the aromatic diamide nucleating agent.

[0048] As can be seen by comparing experiments 1-2 and 5, the organic base catalyst in the present application uses a combination of pyridine-based organic bases and non-pyridine-based organic bases, which significantly improves the purity of the aromatic diamide nucleating agent. Further, as can be seen by comparing experiments 1 and 3-4, the non-pyridine-based organic base uses a combination of triethylamine and N,N-dimethylacetamide, which slightly improves the final yield of the aromatic diamide nucleating agent.

[0049] The above describes in detail the method for synthesizing an aromatic diamide nucleating agent under solvent-free conditions provided by the present application. The principles and implementation modes of the present application are described by applying specific examples, and the above description of the examples is only used to help understand the method of the present application and its core idea. It should be noted that those skilled in the art can make some improvements and modifications to the present application without departing from the principles of the present application, and these improvements and modifications also fall within the protection scope of the claims of the present application.

Claims

1. A method for synthesizing an aromatic diamide-based nucleating agent without a solvent, characterized by, The method comprises the following steps: ； Step S1, synthesis of terephthaloyl chloride: At room temperature, a 250 mL reaction bottle is added with terephthalic acid 15.28 g and dichloro sulfoxide 73.60 g and stirred uniformly, an organic base catalyst is added dropwise, heated to 65°C and stirred at 65°C for 4 hours, the white solid in the reaction mixture is uniformly dispersed; the excess dichloro sulfoxide is recovered by distillation under reduced pressure using a rotary evaporator, the distillation under reduced pressure is at 50-65°C / 20 mmHg, and a fraction is distilled out at 36°C, obtaining white solid terephthaloyl chloride; The molar ratio of terephthalic acid, dichloro sulfoxide and the organic base catalyst is 1:6.7:0.2; the organic base catalyst comprises pyridine organic base catalyst and non-pyridine organic base catalyst, and the molar ratio of the pyridine organic base catalyst and the non-pyridine organic base catalyst is 1:0.20; The non-pyridine organic base catalyst is triethylamine; or the non-pyridine organic base catalyst is N,N-dimethylacetamide; or the non-pyridine organic base catalyst comprises triethylamine and N,N-dimethylacetamide, and the molar ratio of triethylamine and N,N-dimethylacetamide is 1:0.42; Step S2, synthesis of N,N'-dicyclohexyl terephthalamide: At room temperature, the terephthaloyl chloride obtained in step S1 and cyclohexylamine are sequentially added to a grinder, the grinder is started, and grinding is performed at room temperature for 6 hours, and the reaction is completed; the reaction mixture in the grinder is transferred into a beaker, 50 mL of water is added, and the mixture is stirred and pulped, filtered, and washed with water for 4 times, each time with 50 mL, and filtered; the filter cake is air-dried at 70°C for 4 hours, crushed, and N,N'-dicyclohexyl terephthalamide in white powder form is obtained; The molar ratio of terephthaloyl chloride and cyclohexylamine is 1:5.0.

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