阅读说明：本技术 一种n,n’-二氰乙基-二氨基二苯基甲烷的制备方法 (Preparation method of N, N' -dicyanoethyl-diaminodiphenylmethane ) 是由 于波 张聪颖 李鑫 周萌 张文清 姜博 顾志广 智丁未 尚永华 于 2021-08-13 设计创作，主要内容包括：本发明公开了一种N,N’-二氰乙基-二氨基二苯基甲烷的制备方法,将丙烯腈与复合酸催化剂加入到反应釜中反应,生成中间体后,通过与二氨基二苯基甲烷的Michael加成反应制备得到性状稳定的氰乙基胺类化合物。本发明提供的N,N’-二氰乙基-二氨基二苯基甲烷的生产方法,具有操作控制平稳、收率高、产品质量高等优点,填补了国内N,N’-二氰乙基-二氨基二苯基甲烷的生产技术空白；而且本发明得到的N,N’-二氰乙基-二氨基二苯基甲烷同样具有与环氧树脂、异氰酸酯等的良好反应性,相较现有的二氨基二苯基甲烷,它的毒性更小、试用期缩短、韧性更强。(The invention discloses a preparation method of N, N' -dicyanoethyl-diaminodiphenylmethane, which comprises the steps of adding acrylonitrile and a composite acid catalyst into a reaction kettle for reaction, generating an intermediate, and carrying out Michael addition reaction with diaminodiphenylmethane to prepare a cyanoethylamine compound with stable properties. The production method of the N, N '-dicyanoethyl-diaminodiphenylmethane provided by the invention has the advantages of stable operation and control, high yield, high product quality and the like, and fills up the domestic blank of the production technology of the N, N' -dicyanoethyl-diaminodiphenylmethane; the N, N' -dicyanoethyl-diaminodiphenylmethane obtained by the method also has good reactivity with epoxy resin, isocyanate and the like, and has lower toxicity, shorter trial period and stronger toughness compared with the prior diaminodiphenylmethane.)

1. A preparation method of N, N' -dicyanoethyl-diaminodiphenylmethane is characterized by comprising the following steps: obtained by reacting diaminodiphenylmethane and acrylonitrile in the presence of a complex acid catalyst, preferably comprising the steps of:

(1) adding acrylonitrile, hydroquinone and a composite acid catalyst into a reaction kettle in proportion to pre-react the acrylonitrile and the catalyst to obtain a reaction mixture containing an intermediate;

(2) and (2) continuously dripping the diaminodiphenylmethane organic solution with the corresponding proportion into the reaction mixture in the step (1) for addition reaction for a period of time to prepare the crude product of the N, N' -dicyanoethyl-diaminodiphenylmethane.

2. The method according to claim 1, wherein the diaminodiphenylmethane is one or both of 4,4 '-diaminodiphenylmethane and 2, 4' -diaminodiphenylmethane.

3. The method according to claim 1 or 2, characterized in that: in the step (1), the molar ratio of the acrylonitrile to the composite acid catalyst is 1: 0.005-0.1, preferably 1: 0.025-0.05.

4. The method according to any one of claims 1-3, wherein: in the step (1), the molar ratio of the acrylonitrile to the hydroquinone is 1: 0.005-0.02, preferably 1: 0.075-0.01.

5. The method according to any one of claims 1-4, wherein: in the step (1), the composite acid catalyst is selected from ZnCl₂/HAc、CuCl/HAc、Zn(AcO)₂/HAc、Al(AcO)₃/HAc、Cu(AcO)₂/HAc、ZnCl₂Benzoic acid, ZnCl₂/HCl、FeCl₃/HCl、AlCl₃/ZnCl₂、AlCl₃/CuCl₂、AlCl₃/CuSO₄、AlCl₃/FeCl₃、AlCl₃/Cu(AcO)₂·3H₂At least one kind of O, preferably Zn (AcO)₂/HAc。

6. The method of claim 5, wherein: in the step (1), the molar ratio of the two components in the composite acid catalyst is 1: 0.25-1.5, preferably 1: 0.75-1.25.

7. The method according to any one of claims 1-6, wherein: in the step (1), the pre-reaction is carried out at the reaction temperature of 30-50 ℃ for 30-60 min.

8. The method according to any one of claims 1-7, wherein: in the step (2), the molar ratio of the diaminodiphenylmethane to the acrylonitrile is 1: 1.5-2.5, preferably 1: 2.0-2.2.

9. The method according to any one of claims 1-8, wherein: in the step (2), the solvent in the diaminodiphenylmethane organic solution is at least one selected from methanol, ethanol, isopropanol, tetrahydrofuran, cyclohexane and ethyl acetate, preferably tetrahydrofuran; the mass ratio of the diaminodiphenylmethane to the organic solvent is 1: 0.5-5, preferably 1: 1-3.

10. The method according to any one of claims 1-9, wherein: in the step (2), the addition reaction is carried out at the reaction temperature of 50-120 ℃, preferably 80-100 ℃; the reaction time is 6-18 h, preferably 10-12 h.

Technical Field

The invention belongs to the field of organic synthesis, and particularly relates to a preparation method of N, N' -dicyanoethyl-diaminodiphenylmethane.

Background

The epoxy resin is a linear thermoplastic resin, and has excellent physical properties, electrical insulation properties and cohesiveness, so that the epoxy resin is widely applied to various fields such as coatings, composite materials, adhesives and the like; however, since the epoxy resin cannot be cured and does not have any use performance, the curing agent has excellent practical value only by being compounded with the curing agent to generate a cured product with a three-dimensional network structure, and therefore, the curing agent is an essential important component in the use process of the epoxy resin.

Epoxy resin curing agents are various in types, common aliphatic amine, alicyclic amine, aromatic amine, polyamide, tertiary amine, modified amine and the like, and different structures of the curing agents directly affect the technical process and the physical and chemical properties of products, so that the corresponding types of epoxy resin curing agents need to be selected according to different application scenes. As for the aromatic amine curing agent, the curing product of the aromatic amine curing agent and the epoxy resin has stronger impact resistance, compression resistance and tensile resistance to a certain extent due to a rigid benzene ring structure of the curing product, so that the aromatic amine curing agent is widely applied to potting or casting materials. The aromatic amine curing agent generally has the characteristics of long service life and better heat resistance, chemical resistance, aging resistance, electrical property and mechanical property of a cured product, but also has some defects: firstly, most of aromatic amine curing agents are solid, can be cured with epoxy resin only in a high-temperature molten state, and have weaker alkalinity than aliphatic amine and much slower reactivity with the epoxy resin due to the steric hindrance of aromatic rings, so that the curing by heating is necessary, the trial period of the compound is shortened, and the technical performance of products is possibly adversely affected; secondly, the aromatic amine has higher toxicity, and can release amine vapor under the high-temperature curing condition, which is harmful to human health, so that the chemical modification is essential for reducing the toxicity; thirdly, the toughness of the epoxy resin product cured by the aromatic amine is not enough, so that a flexible chain is connected to an amino end when necessary, and the toughness and the strength of the product can be improved.

The modification technique of the aromatic amine curing agent comprises addition modification with epoxy resin, addition modification with ethylene oxide or propylene oxide, Michael addition modification, Mannich reaction modification, ketimine modification and the like. Among these, Michael addition modification techniques include Michael addition modification of aromatic amines with acrylonitrile. Such a modification method has the following advantages: firstly, the added beta-cyanoethylated aromatic amine can be used as an important intermediate of fine chemicals such as pesticides, dyes, medicines, pigments, resin curing agents and the like; and secondly, the aminopropyl aromatic amine obtained by hydrogenating the beta-cyanoethylated aromatic amine has the advantages of low curing temperature of the epoxy resin, prolonged working life, reduced toxicity and enhanced toughness.

Patent CN 107235844A discloses a method for synthesizing a normal temperature curing high temperature resistant epoxy resin curing agent, which takes diaminodiphenylmethane and acrylonitrile as raw materials, the diaminodiphenylmethane and the acrylonitrile are mixed according to a certain mass ratio to obtain a mixed solution, and the mixed solution is added into a reaction kettle and stirred and heated; when the mixed solution reaches a certain temperature, the pressure in the kettle is equivalent to the critical vapor pressure of acrylonitrile, when the pressure is reduced to normal pressure, the reaction is finished, the reaction temperature is 130-160 ℃, and the reaction pressure is not more than 1.5 MPa. The method simplifies the preparation process to a certain extent, but the reaction temperature is too high, and the method is not suitable for industrial production considering the risk that acrylonitrile is easy to ignite and explode under high temperature.

Disclosure of Invention

The invention aims to provide a preparation method of N, N' -dicyanoethyl-diaminodiphenylmethane aiming at the shortage and existing problems of the prior domestic production technology, and the preparation method has the advantages of stable operation and control, high yield, high product quality and the like. In order to achieve the above purpose, the invention adopts the following technical scheme to achieve the purpose:

a process for preparing N, N' -dicyanoethyl-diaminodiphenyl methane includes reaction between diaminodiphenyl methane and acrylonitrile in the presence of composite acid catalyst. As a preferred scheme, the method comprises the following steps:

(1) adding acrylonitrile, hydroquinone and a composite acid catalyst into a reaction kettle in proportion at room temperature to pre-react the acrylonitrile and the catalyst to obtain a reaction mixture containing an intermediate;

(2) heating to reaction temperature, continuously dripping the diaminodiphenylmethane organic solution with the corresponding proportion into the reaction mixture in the step (1), keeping the reaction temperature constant, and continuously carrying out addition reaction for a period of time to obtain the crude product of the N, N' -dicyanoethyl-diaminodiphenylmethane.

The reaction of the present invention is shown in formula I below.

The inventor researches and discovers that in the addition reaction of diaminodiphenylmethane and acrylonitrile, acrylonitrile is firstly pre-reacted with a composite acid catalyst to generate a reaction mixture containing an intermediate, and after the pre-reaction is carried out to a certain degree, diaminodiphenylmethane is added for the addition reaction, so that the reaction temperature can be effectively reduced, the high yield of N, N' -dicyanoethyl-diaminodiphenylmethane is realized, the process safety coefficient is high, and the industrialization is easy to realize.

Preferably, the method also comprises the step (3), the acrylonitrile and the organic solvent with low boiling point are removed from the crude product through atmospheric distillation, then the crude product is transferred into a beaker filled with warm water, is stirred continuously and is cooled to room temperature naturally, and then the crude product is filtered, washed and dried to obtain the N, N' -dicyanoethyl-diaminodiphenylmethane.

Preferably, the diaminodiphenylmethane is one or both of 4,4 '-diaminodiphenylmethane and 2, 4' -diaminodiphenylmethane.

Preferably, in the step (1), the molar ratio of the acrylonitrile to the composite acid catalyst is 1:0.005 to 0.1, preferably 1:0.025 to 0.05.

Preferably, in the step (1), the molar ratio of acrylonitrile to hydroquinone is 1: 0.005-0.02, preferably 1: 0.075-0.01.

Preferably, in step (1), the complex acid catalyst is selected from ZnCl₂/HAc、CuCl/HAc、Zn(AcO)₂/HAc、Al(AcO)₃/HAc、Cu(AcO)₂/HAc、ZnCl₂Benzoic acid, ZnCl₂/HCl、FeCl₃/HCl、AlCl₃/ZnCl₂、AlCl₃/CuCl₂、AlCl₃/CuSO₄、AlCl₃/FeCl₃、AlCl₃/Cu(AcO)₂·3H₂At least one kind of O, preferably Zn (AcO)₂/HAc。

In the step (1), the molar ratio of the two components in the composite acid catalyst is 1: 0.25-1.5, preferably 1: 0.75-1.25.

Preferably, in the step (1), the pre-reaction is carried out at a reaction temperature of 30-50 ℃ for 30-60 min.

Preferably, in the step (2), the molar ratio of diaminodiphenylmethane to acrylonitrile is 1: 1.5-2.5, preferably 1:2.0 to 2.2.

Preferably, in the step (2), the organic solvent is at least one selected from methanol, ethanol, isopropanol, tetrahydrofuran, cyclohexane and ethyl acetate, preferably tetrahydrofuran; the mass ratio of the diaminodiphenylmethane to the organic solvent is 1: 0.5-5, preferably 1: 1-3.

Preferably, in the step (2), the reaction temperature of the addition reaction is 50-120 ℃, and preferably 80-100 ℃. The reaction time is 6-18 h, preferably 10-12 h.

Preferably, in the step (3), the atmospheric distillation temperature is 80-120 ℃, and preferably 90-110 ℃; the treatment time is 0.5-5 h, preferably 1-3 h.

The invention has the beneficial effects that:

(1) the amino group on the aromatic amine is weak in alkalinity, the cyanoethylation reaction is difficult to carry out, and the cyanoethylation technology is difficult to realize due to the electronic conjugation effect of the bicyclic aromatic amine. The invention provides an improved method for preparing N, N' -dicyanoethyl-diaminodiphenylmethane. The method adopts a composite acid catalyst, has high product yield and high safety factor, and fills up the blank of the domestic N, N' -dicyanoethyl-diaminodiphenylmethane production technology.

(2) Firstly, pre-reacting acrylonitrile with a composite acid catalyst to generate an intermediate, fully improving the reaction activity of the acrylonitrile, and then adding diaminodiphenylmethane into a reaction mixture to promote the addition reaction to be smoothly carried out; especially, under the condition of excessive acrylonitrile, the diaminodiphenylmethane is added in a continuous dropwise feeding mode, so that the reaction process can be accelerated.

(3) The composite acid catalyst used in the invention is compounded by Lewis acid/organic acid, Lewis acid/Lewis acid and the like, and the polarity of the catalyst is very small, so that the catalyst can be well dissolved in acrylonitrile; and the metal cations have strong coordination capacity with nitrogen atoms on acrylonitrile, and the catalytic efficiency is higher under the action of acid.

Detailed Description

The present invention will be further described with reference to the following examples, but the present invention is not limited to the examples.

Gas chromatograph: agilent 7890 and DB-5(30 m.times.0.25 mmID.times.0.25 μm) were used, with a sample injector temperature of 280 ℃ and a detector temperature of 300 ℃. The temperature-raising program is as follows: the initial column temperature was 50 ℃ and held for 2 min; heating to 80 deg.C at 5 deg.C/min, and maintaining for 0 min; the temperature is raised to 300 ℃ at a speed of 15 ℃/min and kept for 15 min. The content of each component is determined by a normalization method.

Example 1

(1) 2.0mol of acrylonitrile, 0.15mol of hydroquinone and 0.04mol of Zn (AcO) are added into a 2L reaction kettle₂And 0.04mol of HAc, and stirring is continuously carried out at 30 ℃ for 60min under a nitrogen atmosphere until the catalyst is completely dissolved.

(2) The reaction temperature was raised to 80 ℃ within half an hour, at which time a THF solution containing 1.0mol of diaminodiphenylmethane (mass ratio of diaminodiphenylmethane to THF 1:1) was continuously added dropwise to the reaction mixture over a period of not more than 1 hour, and after the addition was completed, the reaction was carried out at 80-85 ℃ for 12 hours until the diaminodiphenylmethane reaction was complete, and 3 drops of the reaction solution were diluted to 1ml with ethanol for chromatographic analysis, and as a result, 20ppm of acrylonitrile remained and the conversion of diaminodiphenylmethane was 98.9%.

(3) Transferring the material into a 1L flask, heating the material to 110 ℃ in an oil bath, treating the material for 1h, removing acrylonitrile and tetrahydrofuran with low boiling point, transferring the material into a beaker filled with 500ml of 70 ℃ water, continuously stirring, naturally cooling to room temperature, filtering, washing with water to be neutral, and drying to obtain an off-white flaky crystal, namely the N, N' -dicyanoethyl-diaminodiphenylmethane.

The chromatographic analysis product composition is as follows: 2.4 wt% of one-molecular adduct, 96.3 wt% of two-molecular adduct, 1.0 wt% of three-molecular adduct and 0.3 wt% of four-molecular adduct.

Example 2

(1) 2.0mol of acrylonitrile, 0.15mol of hydroquinone and 0.04mol of Cu (AcO) are added into a 2L reaction kettle₂And 0.04mol of HAc, and stirring is continuously carried out at 30 ℃ for 60min under a nitrogen atmosphere until the catalyst is completely dissolved.

(2) The reaction temperature is raised to 80 ℃ within half an hour, at the moment, 1.0mol of THF solution of diaminodiphenylmethane (the mass ratio of diaminodiphenylmethane to THF is 1:1) is continuously dripped into the reaction mixture, the dripping time is not more than 1 hour, after the dripping is finished, the reaction is carried out for 12 hours at the temperature of 80-85 ℃ until the diaminodiphenylmethane is completely reacted, 3 drops of reaction liquid are diluted to 1ml by ethanol for chromatographic analysis, and the result shows that 45ppm of acrylonitrile remains and the conversion rate of diaminodiphenylmethane is 97.2%.

(3) Transferring the material into a 1L flask, heating the material to 110 ℃ in an oil bath, treating the material for 1h, removing acrylonitrile and tetrahydrofuran with low boiling point, transferring the material into a beaker filled with 500ml of 70 ℃ water, continuously stirring, naturally cooling to room temperature, filtering, washing with water to be neutral, and drying to obtain an off-white flaky crystal, namely the N, N' -dicyanoethyl-diaminodiphenylmethane.

The chromatographic analysis product composition is as follows: the content of one-molecular adduct was 3.8 wt%, the content of two-molecular adduct was 95.2 wt%, the content of three-molecular adduct was 0.8 wt%, and the content of four-molecular adduct was 0.2 wt%.

Example 3

(1) 2.0mol of acrylonitrile, 0.15mol of hydroquinone and 0.04mol of Al (AcO) are added into a 2L reaction kettle₃And 0.04mol of HAc, and stirring is continuously carried out at 30 ℃ for 60min under a nitrogen atmosphere until the catalyst is completely dissolved.

(2) The reaction temperature is raised to 80 ℃ within half an hour, at the moment, 1.0mol of THF solution of diaminodiphenylmethane (the mass ratio of diaminodiphenylmethane to THF is 1:1) is continuously dripped into the reaction mixture, the dripping time is not more than 1 hour, after the dripping is finished, the reaction is carried out for 12 hours at the temperature of 80-85 ℃ until the diaminodiphenylmethane is completely reacted, 3 drops of reaction liquid are diluted to 1ml by ethanol for chromatographic analysis, and the result shows that 32ppm of acrylonitrile remains and the conversion rate of diaminodiphenylmethane is 98.0%.

(3) Transferring the material into a 1L flask, heating the material to 110 ℃ in an oil bath, treating the material for 1h, removing acrylonitrile and tetrahydrofuran with low boiling point, transferring the material into a beaker filled with 500ml of 70 ℃ water, continuously stirring, naturally cooling to room temperature, filtering, washing with water to be neutral, and drying to obtain an off-white flaky crystal, namely the N, N' -dicyanoethyl-diaminodiphenylmethane.

The chromatographic analysis product composition is as follows: the content of one-molecular adduct was 3.0 wt%, the content of two-molecular adduct was 95.8 wt%, the content of three-molecular adduct was 0.9 wt%, and the content of four-molecular adduct was 0.3 wt%.

Example 4

(1) 2.2mol of acrylonitrile, 0.16mol of hydroquinone and 0.04mol of Zn (AcO) are added into a 2L reaction kettle₂And 0.04mol of HAc, and stirring is continued at 50 ℃ for 30min under a nitrogen atmosphere until the catalyst is completely dissolved.

(2) The reaction temperature is raised to 100 ℃ within half an hour, at the moment, 1.0mol of THF solution of diaminodiphenylmethane (the mass ratio of diaminodiphenylmethane to THF is 1:3) is continuously dripped into the reaction mixture, the dripping time is not more than 1 hour, after the dripping is finished, the reaction is carried out for 12 hours at the temperature of 100 ℃ to 105 ℃ until the diaminodiphenylmethane is completely reacted, 3 drops of reaction liquid are diluted to 1ml by ethanol for chromatographic analysis, and the result shows that 50ppm of acrylonitrile remains and the conversion rate of diaminodiphenylmethane is 99.4%.

(3) Transferring the material into a 1L flask, heating the material to 90 ℃ in an oil bath, treating the material for 3h, removing acrylonitrile and tetrahydrofuran with low boiling point, transferring the material into a beaker filled with 500ml of 70 ℃ water, continuously stirring, naturally cooling to room temperature, filtering, washing with water to be neutral, and drying to obtain an off-white flaky crystal, namely the N, N' -dicyanoethyl-diaminodiphenylmethane.

The chromatographic analysis product composition is as follows: 1.5 wt% of one-molecular adduct, 97.0 wt% of two-molecular adduct, 1.2 wt% of three-molecular adduct and 0.3 wt% of four-molecular adduct.

Example 5

(1) 2.0mol of acrylonitrile, 0.15mol of hydroquinone and 0.05mol of Zn (AcO) are added into a 2L reaction kettle₂And 0.05mol of HAc, and stirring is continued at 40 ℃ for 45min under a nitrogen atmosphere until the catalyst is completely dissolved.

(2) The reaction temperature is raised to 90 ℃ within half an hour, at the moment, 1.0mol of THF solution of diaminodiphenylmethane (the mass ratio of diaminodiphenylmethane to THF is 1:2) is continuously dripped into the reaction mixture, the dripping time is not more than 1 hour, after the dripping is finished, the reaction is carried out for 12 hours at the temperature of 90-95 ℃ until the diaminodiphenylmethane is completely reacted, 3 drops of reaction liquid are diluted to 1ml by ethanol for chromatographic analysis, and the result shows that 15ppm of acrylonitrile remains and the conversion rate of diaminodiphenylmethane is 99.2%.

(3) Transferring the material into a 1L flask, heating the material to 100 ℃ in an oil bath, treating the material for 2 hours, removing acrylonitrile and tetrahydrofuran with low boiling point, transferring the material into a beaker filled with 500ml of 70 ℃ water, continuously stirring, naturally cooling the material to room temperature, filtering the material, washing the material to be neutral, and drying the material to obtain an off-white flaky crystal, namely the N, N' -dicyanoethyl-diaminodiphenylmethane.

The chromatographic analysis product composition is as follows: 1.3 wt% of one-molecular adduct, 97.1 wt% of two-molecular adduct, 1.2 wt% of three-molecular adduct and 0.4 wt% of four-molecular adduct.

Comparative example 1

The operation was carried out without addition of catalyst and with mixed feeds, with reference to patent CN 107235844 a, example 1.

2.0mol of acrylonitrile, 0.15mol of hydroquinone and 1mol of tetrahydrofuran solution of diaminodiphenylmethane are added into a 2L reaction kettle; sealing the reaction kettle, heating to 140 ℃, raising the highest pressure of the reaction kettle to 0.5MPa, then preserving the temperature, gradually reducing the pressure along with the reaction, finding that the pressure is reduced to 0.1MPa after 16h, and reducing the temperature to the normal temperature. After 3 drops of the reaction mixture were diluted with ethanol to 1ml, the resulting mixture was analyzed by chromatography, which revealed that 200ppm of acrylonitrile remained and the conversion of diaminodiphenylmethane was 95.6%.

The chromatographic analysis product composition is as follows: 10.6 wt% of one-molecular adduct, 87.2 wt% of two-molecular adduct, 1.8 wt% of three-molecular adduct and 0.4 wt% of four-molecular adduct.

Comparative example 2

The operation was carried out without addition of catalyst and with mixed feeds, with reference to patent CN 107235844 a, example 1.

2.0mol of acrylonitrile, 0.15mol of hydroquinone and 1mol of tetrahydrofuran solution of diaminodiphenylmethane are added into a 2L reaction kettle; sealing the reaction kettle, heating to 160 ℃, raising the highest pressure of the reaction kettle to 0.6MPa, then preserving the temperature, gradually reducing the pressure along with the reaction, finding that the pressure is reduced to 0.1MPa after 16h, and reducing the temperature to the normal temperature. After 3 drops of the reaction solution were diluted with ethanol to 1ml, the resulting mixture was analyzed by chromatography, which revealed that 300ppm of acrylonitrile remained and that the conversion of diaminodiphenylmethane was 94.2%.

The chromatographic analysis product composition is as follows: 11.2 wt% of one-molecular adduct, 86.4 wt% of two-molecular adduct, 1.6 wt% of three-molecular adduct and 0.8 wt% of four-molecular adduct.

The above examples are merely illustrative of the present invention and are not intended to limit the embodiments of the present invention. Variations or modifications may occur to those skilled in the art based on the foregoing description, and it is not intended to recite all embodiments herein. All the changes or variations extending on the basis of the technical scheme of the invention are in the invention.