Compound N 1 -(3-aminopropyl)-N 3 -Cyclohexyl-1,3-propylenediamine and its preparation method and application

Abstract

This invention provides a compound N 1 -(3-aminopropyl)-N 3 1,3-Cyclohexyl-1,3-propanediamine and its preparation method and application. The preparation method includes the following steps: 1) Mixing N-(3-aminopropyl)cyclohexylamine, water and auxiliaries, then adding acrylonitrile to react, and after the reaction, distilling under reduced pressure to obtain an intermediate; 2) Mixing Raney catalyst, basic modifier and solvent, then introducing hydrogen to adjust the system to the reaction pressure, heating to the reaction temperature, and then adding the intermediate obtained in step 1) under a hydrogen atmosphere to carry out a hydrogenation reaction to obtain N as shown in formula (1). 1 -(3-aminopropyl)-N 3 Cyclohexyl-1,3-propanediamine. This method has advantages such as inexpensive and readily available raw materials, long catalyst lifetime, low deactivation, and low production cost, and has good prospects for industrialization. The compounds of this invention can be used as epoxy resin curing agents.

Description

Technical Field

[0001] The present invention relates to a new compound N 1 -(3-aminopropyl)-N 3 -Cyclohexyl-1,3-propylenediamine and preparation method, and use thereof as epoxy curing agent. Background Art

[0002] There are three main types of amines currently used in the field of epoxy curing agents: alicyclic amines, fatty amines and aromatic amines. Common alicyclic amines (such as HMDA, IPDA and 1,3-BAC) have the characteristics of strong yellowing resistance and high hardness of products, but because the fatty chain of the molecule is not long enough, the impact strength of the products is poor; although aliphatic amines have good impact strength, the molecules are highly volatile and toxic, and the hardness of the products is poor; aromatic amines are gradually banned due to their high toxicity and poor yellowing resistance.

[0003] With the rapid development of downstream applications of epoxy curing agents, there is a certain demand for new molecular amines with specific structures. It is necessary to develop an epoxy curing agent that can give the product both impact strength and hardness to meet the needs of downstream customers. Summary of the invention

[0004] Based on the above-mentioned deficiencies in the prior art, the present invention provides a new compound N 1 -(3-aminopropyl)-N 3 -cyclohexyl-1,3-propylenediamine and its preparation method, the invention uses N-(3-aminopropyl)cyclohexylamine, acrylonitrile and hydrogen as raw materials to synthesize N 1 -(3-aminopropyl)-N 3 -cyclohexyl-1,3-propylenediamine. The raw materials of this method are cheap and easy to obtain, the catalyst has a long life, is not easy to deactivate, has a low production cost, and has good industrialization prospects.

[0005] At the same time, the present invention also provides the use of the above compound as an epoxy resin curing agent, and the obtained product not only meets the requirements of both impact strength and hardness, but also has the advantages of strong yellowing resistance and high glass transition temperature.

[0006] In order to achieve the above-mentioned object of the invention, the present invention adopts the following technical solution:

[0007] The present invention provides a compound N 1 -(3-aminopropyl)-N 3 -cyclohexyl-1,3-propanediamine, which has the structure shown in formula (1):

[0008]

[0009] The present invention also provides a N1 -(3-aminopropyl)-N 3 -A method for preparing cyclohexyl-1,3-propylenediamine, comprising the steps of:

[0010] 1) mixing N-(3-aminopropyl)cyclohexylamine, water and an auxiliary agent, then adding acrylonitrile to react, and then performing vacuum distillation to obtain an intermediate after the reaction is completed;

[0011] 2) mixing the Raney catalyst, the alkaline modifier and the solvent, then introducing hydrogen to adjust the system to the reaction pressure, and heating to the reaction temperature, and then adding the intermediate obtained in step 1) under a hydrogen atmosphere to carry out a hydrogenation reaction to obtain N 1 -(3-aminopropyl)-N 3 -cyclohexyl-1,3-propanediamine.

[0012] The main reaction formula involved in the method of the present invention is as follows:

[0013]

[0014] In the present invention, the molar ratio of acrylonitrile to N-(3-aminopropyl)cyclohexylamine in step 1) is 0.8-0.99:1, preferably 0.9-0.95:1; by controlling the molar ratio of acrylonitrile to aminopropylcyclohexylamine to be lower than 1:1, the generation of dinitrile can be effectively reduced.

[0015] In the present invention, the molar ratio of water to N-(3-aminopropyl)cyclohexylamine in step 1) is 0.25-2:1, preferably 0.5-1:1.

[0016] In the present invention, the auxiliary agent in step 1) is selected from N,N-dimethylethanolamine and / or N,N-diethylethanolamine;

[0017] The dosage of the auxiliary agent is 5-20wt% of the mass of N-(3-aminopropyl)cyclohexylamine, preferably 8-15wt%.

[0018] In the present invention, the intermediate obtained in step 1) is cyanoethylaminopropylcyclohexylamine, which has the structure shown in the following formula (2):

[0019]

[0020] According to the structural characteristics of the compound of formula (1), the intermediate (cyanoethylaminopropylcyclohexylamine) of formula (2) can be obtained by first reacting N-(3-aminopropyl)cyclohexylamine with acrylonitrile, and then the target product can be obtained by hydrogenation. However, the inventors have found in their research that two dinitrile compounds are generated during the reaction of aminopropylcyclohexylamine with acrylonitrile, and the structures are as follows:

[0021]

[0022] During the hydrogenation process, dinitrile 1 and dinitrile 2 are prone to intramolecular cyclization and intermolecular deamination to form macromolecular byproducts. The blocking of the catalyst surface pores and the covering of the active sites by the macromolecular byproducts will cause the catalyst to deactivate quickly. For this reason, the researchers of the present invention have found through further research that the introduction of auxiliary agents N, N-dimethylethanolamine and / or N, N-diethylethanolamine in the reaction system can effectively solve the above problems. The N, N-dimethylethanolamine and / or N, N-diethylethanolamine used in the present invention contain hydroxyl groups and tertiary amine groups at specific positions in their structures. On the one hand, the hydroxyl groups therein can form hydrogen bonds with the secondary nitrogen on the intermediate, thereby generating certain steric hindrances, preventing the intermediate from further reacting with acrylonitrile to obtain dinitrile 1 and dinitrile 2, thereby reducing the poisoning of the two byproducts to the catalyst in the next step of hydrogenation; on the other hand, the tertiary amine has a strong steric hindrance, and is not easy to react with acrylonitrile under the conditions of the present invention, avoiding the generation of new impurities. In addition, the auxiliary agent of the present invention has a low boiling point, and the reuse of raw materials can be achieved by simple distillation.

[0023] In the present invention, the reaction temperature in step 1) is 10-40°C, preferably 20-30°C; the heat preservation reaction time is 0.2-2h, preferably 0.5-1h.

[0024] In the present invention, the acrylonitrile in step 1) is continuously fed, preferably dripped, for 2-6 hours, preferably 3-4 hours; after the feeding is completed, the heat preservation reaction is continued, and the feeding time is not included in the above heat preservation reaction time.

[0025] In the present invention, the vacuum distillation in step 1) has a vacuum degree of 0.5-5 KPa, preferably 1-2 KPa, and a temperature of 88-150° C., preferably 100-112° C.; N-(3-aminopropyl)cyclohexylamine, water and additives in the reaction solution can be removed by vacuum distillation, and the removed N-(3-aminopropyl)cyclohexylamine, water and additives can be recycled and used in the form of a mixture or a pure substance, preferably a mixture, to reduce energy consumption and operation complexity.

[0026] In the present invention, the Raney catalyst in step 2) is selected from one or more of Raney nickel and Raney cobalt, preferably one or more of Grace 2400, Grace 2800, Grace 2724, Xunkai 1200 and Xunkai 3300;

[0027] The amount of the Raney catalyst used is 10-30wt% of the intermediate mass, preferably 15-25wt%.

[0028] In the present invention, the alkaline modifier in step 2) is an alkaline compound selected from lithium hydroxide, sodium hydroxide, potassium hydroxide, ammonia water (such as ammonia water with a concentration of 25wt%), preferably one or more of lithium hydroxide and sodium hydroxide; preferably, the alkaline modifier is prepared as an aqueous solution with a concentration of 5-15wt% before use;

[0029] The amount of the alkaline modifier used is 2-20 wt %, preferably 5-10 wt %, of the mass of the Raney catalyst.

[0030] In the present invention, the solvent in step 2) is selected from one or more of methanol, ethanol, tetrahydrofuran, and dioxane, preferably ethanol and / or tetrahydrofuran;

[0031] The amount of the solvent used is 0.5-2 times the mass of the intermediate, preferably 0.75-1.25 times.

[0032] In the present invention, the reaction pressure in step 2) is 3-8 MPaG, preferably 4-6 MPaG; the reaction temperature is 70-140°C, preferably 80-120°C.

[0033] In the present invention, the intermediate in step 2) is continuously fed, preferably dropwise, for a feeding time of 2-8 hours, preferably 4-6 hours; after the feeding is completed, the temperature is kept high for hydrogenation reaction.

[0034] In the present invention, the reaction time of the hydrogenation reaction in step 2) after the addition is 0.2-2h, preferably 0.4-0.6h (the above intermediate addition time is not included in the reaction time).

[0035] In the present invention, step 2) after the hydrogenation reaction is completed, further comprises cooling, filtering and other operations to obtain 1 -(3-aminopropyl)-N 3 The mother liquor of -cyclohexyl-1,3-propylenediamine, and the subsequent refined pure product can be obtained by distillation, thin film evaporation and other methods, which are conventional operations in the field and are not specifically limited in the present invention.

[0036] At the same time, the present invention also provides N shown in the above formula (1) 1 -(3-aminopropyl)-N 3 -The application of cyclohexyl-1,3-propylenediamine compounds as epoxy curing agents is particularly suitable for epoxy flooring, seam beautifiers, adhesives, stone glues and other fields. The products take into account the requirements of impact strength and hardness, and also have the advantages of strong yellowing resistance and high glass transition temperature.

[0037] Compared with the prior art, the technical solution of the present invention has the following beneficial effects:

[0038] (1) The present invention develops a N 1-(3-aminopropyl)-N 3 -cyclohexyl-1,3-propylenediamine compound, and proposed a new preparation route with raw materials such as N-(3-aminopropyl)cyclohexylamine, acrylonitrile, hydrogen, etc., which makes up for the shortcomings of this type of epoxy curing agent. The route of the present invention has the advantages of easy availability of raw materials, the use of existing commercial catalysts, mild reaction conditions, high product yield, long catalyst life, low production cost, and good commercial prospects.

[0039] (2) The process of the present invention can significantly reduce the content of dinitrile 1 and dinitrile 2 by introducing an auxiliary agent, so that the total content of dinitrile is ≤0.5%, and the selectivity of the intermediate is ≥99%. After the dinitrile impurities are reduced to this content, the poisoning of the catalyst in the subsequent hydrogenation reaction can be eliminated. The catalyst performance is stable and can be continuously applied for more than 30 batches, and the product yield is ≥98%.

[0040] (3) The unreacted N-(3-aminopropyl)cyclohexylamine, auxiliary agent and water of the present invention can be recycled, and the auxiliary agent does not need to be added again, which can effectively reduce material consumption and the generation of three wastes. It is an economical, green and sustainable development process that conforms to the national development strategy. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 is the mass spectrum of the intermediate prepared by step 1) in Example 1;

[0042] Figure 2 This is the NMR carbon spectrum of the product prepared by step 2) in Example 1. DETAILED DESCRIPTION

[0043] In order to better understand the technical solution of the present invention, the following examples will further illustrate the method provided by the present invention, but the present invention is not limited to the listed examples, and should also include any other known changes within the scope of the claims of the present invention.

[0044] The conditions for gas chromatography analysis in the following examples are: Agilent DB-5 chromatographic column, injection port temperature 280°C, FID detector temperature 300°C, column flow rate 1.3 ml / min, hydrogen flow rate 40 ml / min, air flow rate 400 ml / min, and programmed temperature rise mode: 50°C for 2 min, heating to 80°C at 5°C / min, then heating to 300°C at 15°C / min, and holding for 15 min.

[0045] The GC-MS analysis conditions in the following examples are as follows: Agilent 7890A GC System-5975CMSD, DB-5MS chromatographic column, injection port temperature 280°C, injection volume 0.2 μL, split ratio 30, column temperature 50°C for 2 min, increased to 80°C at 5°C / min, then increased to 280°C at 15°C / min, and maintained for 5 min; connection line temperature 300°C, detector is a quadrupole mass spectrometer, ion source temperature is 230°C, quadrupole temperature is 200°C, and mass number scanning range is 29-800.

[0046] The conditions for the NMR carbon spectroscopy analysis in the following examples are: Bruker AVANCE NEO 600 MHz, 13C frequency: 150.93 MHz, pulse sequence: zgig30, solvent: CDCl3, sampling point number TD: 64K, pre-pulse recovery time D1: 3 s, scan number NS: 1024.

[0047] The main raw materials used in the following examples or comparative examples are from the following sources. Other raw materials are common commercially available unless otherwise specified:

[0048] N-(3-aminopropyl)cyclohexylamine: technical grade, purchased from Solvay Fine Chemicals Co., Ltd.;

[0049] Raney nickel catalyst: Grace 2400 / 2800, purchased from Grace Catalyst Company; Xunkai 1200, purchased from Shanghai Xunkai New Material Technology Co., Ltd.

[0050] Raney cobalt catalyst: Grace 2724, purchased from Grace Catalyst Company; Xunkai 3300, purchased from Shanghai Xunkai New Materials Technology Co., Ltd.

[0051] The main equipment information is as follows:

[0052] High-pressure reactor: specification 1L, manufactured by Yantai Keli Equipment;

[0053] Horizontal flow pump: Model 2PB00C, manufacturer is Beijing Satellite.

[0054] Example 1

[0055] Preparation of Compound N 1 -(3-aminopropyl)-N 3 -cyclohexyl-1,3-propanediamine, the steps are:

[0056] 1) 156 g (1 mol) of N-(3-aminopropyl)cyclohexylamine, 18 g (1 mol) of water, and 15.6 g of N, N-dimethylethanolamine were added to a reaction kettle, and the temperature was raised to 30°C. Acrylonitrile was added dropwise to the reaction kettle for 4 hours, and the amount of acrylonitrile added was 47.7 g (0.9 mol). The reaction was then stopped by keeping the temperature at 30°C for 0.5 hours to obtain an intermediate reaction solution, which was cyanoethylaminopropylcyclohexylamine. The mass spectrometry was used to characterize the reaction solution. The results were as follows: Figure 1 Sampling was performed for gas chromatography analysis, and the conversion of acrylonitrile was 100%, the selectivity of intermediate was 99.5%, the selectivity of dinitrile 1 was 0.12%, and the selectivity of dinitrile 2 was 0.16%.

[0057] The reaction liquid was subjected to vacuum distillation at a vacuum degree of 3 KPa, and the fraction with a top temperature of ≤126° C. was collected. Chromatographic analysis showed that all of the fractions were N-(3-aminopropyl)cyclohexylamine, water and N,N-dimethylethanolamine, which could be reused next time. An intermediate (with a total content of dinitrile 1 and dinitrile 2 of 0.28 wt%) was obtained at the bottom of the tower for the next hydrogenation reaction.

[0058] 2) 10 g of Raney nickel catalyst (Grace 2800), 0.5 g of potassium hydroxide (dissolved in water to form a 10 wt% aqueous solution) and 100 g of ethanol were added to the autoclave, and the autoclave was replaced with nitrogen and hydrogen three times in sequence, and then the hydrogen was charged to 2 MPaG, and the temperature was raised. When the reaction temperature rose to 90° C., the hydrogen pressure was increased to 5 MPaG and maintained at this pressure. The intermediate was uniformly added to the reaction system with a horizontal flow pump. When the feed reached 50 g, the total dropwise addition time was 3 h, the feed was stopped, the reaction was continued for 0.4 h, the temperature was lowered, and the product containing N was obtained by filtration. 1 -(3-aminopropyl)-N 3 The reaction solution of -cyclohexyl-1,3-propylenediamine was characterized by NMR carbon spectroscopy. The results are as follows Figure 2 The sample was taken for gas chromatography analysis, and the catalyst was left in the reactor for further use. The conversion rate of the intermediate was 100%, N 1 -(3-aminopropyl)-N 3 -The yield of cyclohexyl-1,3-propanediamine was 98.5%.

[0059] Repeat the above steps to prepare compound N 1 -(3-aminopropyl)-N 3 -cyclohexyl-1,3-propylenediamine, step 1) using N-(3-aminopropyl)cyclohexylamine, water and N,N-dimethylethanolamine, 2) using a catalyst, the results are shown in Table 1:

[0060] Table 1

[0061]

[0062] Example 2

[0063] Preparation of Compound N 1 -(3-aminopropyl)-N 3 -cyclohexyl-1,3-propanediamine, the steps are:

[0064] 1) 156 g (1 mol) of N-(3-aminopropyl)cyclohexylamine, 9 g (0.5 mol) of water and 23.4 g of N,N-diethylethanolamine were added to a reactor, the temperature was raised to 40° C., acrylonitrile was added dropwise to the reactor for 2 h, the amount of acrylonitrile added was 42.4 g (0.8 mol), and the reaction was stopped by keeping the temperature at 40° C. for 2 h to obtain an intermediate reaction liquid, which was sampled for gas chromatography analysis. The conversion of acrylonitrile was 100%, the selectivity of the intermediate was 99.62%, the selectivity of dinitrile 1 was 0.08%, and the selectivity of dinitrile 2 was 0.13%.

[0065] The reaction liquid was subjected to vacuum distillation at a vacuum degree of 1 KPa, and the fractions with a top temperature of ≤100° C. were collected. Chromatographic analysis showed that they were all N-(3-aminopropyl)cyclohexylamine, water and N,N-diethylethanolamine, which could be reused next time. An intermediate (with a total content of dinitrile 1 and dinitrile 2 of 0.21 wt%) was obtained at the bottom of the tower for the next hydrogenation reaction.

[0066] 2) 7.5 g of Raney cobalt catalyst (Grace 2724), 0.15 g of lithium hydroxide (dissolved in water to form a 10 wt% aqueous solution) and 62.5 g of tetrahydrofuran were added to the autoclave, and the autoclave was replaced with nitrogen and hydrogen three times in sequence, and then the hydrogen was charged to 1 MPaG, and the temperature was raised. When the reaction temperature rose to 140° C., the hydrogen pressure was increased to 3 MPaG and maintained at this pressure. The intermediate was uniformly added dropwise to the reaction system using a horizontal flow pump. When the feed reached 50 g, the total dropwise addition time was 2 h, the feed was stopped, the reaction was continued for 0.6 h, the temperature was lowered, and the product containing N was obtained by filtration. 1 -(3-aminopropyl)-N 3 The reaction liquid of -cyclohexyl-1,3-propylenediamine was sampled for gas chromatography analysis, and the catalyst was left in the reactor for further use. The conversion rate of the intermediate was 100%, N 1 -(3-aminopropyl)-N 3 -The yield of cyclohexyl-1,3-propanediamine was 99.4%.

[0067] Repeat the above steps to prepare compound N 1 -(3-aminopropyl)-N 3 -cyclohexyl-1,3-propylenediamine, step 1) using N-(3-aminopropyl)cyclohexylamine, water and N,N-diethylethanolamine, 2) using a catalyst, the results are shown in Table 2:

[0068] Table 2

[0069]

[0070]

[0071] Example 3

[0072] Preparation of Compound N 1 -(3-aminopropyl)-N 3 -cyclohexyl-1,3-propanediamine, the steps are:

[0073] 1) 156 g (1 mol) of N-(3-aminopropyl)cyclohexylamine, 36 g (2 mol) of water and 7.8 g of N,N-dimethylethanolamine were added to a reaction kettle, the temperature was raised to 20° C., acrylonitrile was added dropwise to the reaction kettle for 3 h, the amount of acrylonitrile added was 50.35 g (0.95 mol), and the reaction was stopped by keeping the temperature at 20° C. for 1 h to obtain an intermediate reaction liquid, which was sampled for gas chromatography analysis. The conversion of acrylonitrile was 100%, the selectivity of the intermediate was 99.45%, the selectivity of dinitrile 1 was 0.18%, and the selectivity of dinitrile 2 was 0.20%.

[0074] The reaction liquid was subjected to vacuum distillation at a vacuum degree of 0.5 KPa, and the fractions with a top temperature of ≤88° C. were collected. Chromatographic analysis showed that they were all N-(3-aminopropyl)cyclohexylamine, water and N,N-dimethylethanolamine, which could be reused next time. An intermediate (with a total content of dinitrile 1 and dinitrile 2 of 0.38 wt%) was obtained at the bottom of the tower for the next hydrogenation reaction.

[0075] 2) 15 g of Raney nickel catalyst (Xunkai 1200), 1.5 g of sodium hydroxide (dissolved in water to form a 10 wt% aqueous solution) and 37.5 g of methanol were added to the autoclave, and the gas was replaced with nitrogen and hydrogen three times in sequence, and then the hydrogen was charged to 2 MPaG, and the temperature was raised. When the reaction temperature rose to 80°C, the hydrogen pressure was increased to 4 MPaG and maintained at this pressure. The intermediate was uniformly added to the reaction system with a horizontal flow pump. When the feed reached 50 g, the total dropwise addition time was 4 h, the feed was stopped, the reaction was continued for 0.2 h, the temperature was lowered, and the mixture containing N 1 -(3-aminopropyl)-N 3 The reaction liquid of -cyclohexyl-1,3-propylenediamine was sampled for gas chromatography analysis, and the catalyst was left in the reactor for further use. The conversion rate of the intermediate was 100%, N 1 -(3-aminopropyl)-N 3 -The yield of cyclohexyl-1,3-propanediamine was 98.35%.

[0076] Repeat the above steps to prepare compound N 1-(3-aminopropyl)-N 3 -cyclohexyl-1,3-propylenediamine, step 1) using N-(3-aminopropyl)cyclohexylamine, water and N,N-dimethylethanolamine, 2) using a catalyst, the results are shown in Table 3:

[0077] Table 3

[0078]

[0079]

[0080] Example 4

[0081] Preparation of Compound N 1 -(3-aminopropyl)-N 3 -cyclohexyl-1,3-propanediamine, the steps are:

[0082] 1) 156 g (1 mol) of N-(3-aminopropyl)cyclohexylamine, 4.5 g (0.25 mol) of water and 31.2 g of N,N-diethylethanolamine were added to a reaction kettle, the temperature was raised to 10° C., acrylonitrile was added dropwise to the reaction kettle for 6 h, the amount of acrylonitrile added was 52.47 g (0.99 mol), and the reaction was stopped by keeping the temperature at 10° C. for 0.2 h to obtain an intermediate reaction liquid, which was sampled for gas chromatography analysis. The conversion of acrylonitrile was 100%, the selectivity of the intermediate was 99.21%, the selectivity of dinitrile 1 was 0.24%, and the selectivity of dinitrile 2 was 0.23%.

[0083] The reaction liquid was subjected to vacuum distillation at a vacuum degree of 2 KPa, and the fraction with a top temperature of ≤112° C. was collected. Chromatographic analysis showed that all of the fractions were N-(3-aminopropyl)cyclohexylamine, water and N,N-diethylethanolamine, which could be reused next time. An intermediate (with a total content of dinitrile 1 and dinitrile 2 of 0.47 wt%) was obtained at the bottom of the tower for the next hydrogenation reaction.

[0084] 2) Add 5g of Raney cobalt catalyst (Xunkai 3300), 1g of ammonia water (mass concentration of 25%) and 50g of dioxane into the autoclave, replace with nitrogen and hydrogen three times in sequence, fill with hydrogen to 4MPaG, start heating, when the reaction temperature rises to 120°C, pressurize the hydrogen pressure to 8MPaG and maintain this pressure, use a horizontal flow pump to uniformly add the intermediate to the reaction system, when the feed reaches 50g, the total dropwise addition time is 6h, stop feeding, continue the reaction for 0.5h, cool down, filter to obtain N 1 -(3-aminopropyl)-N 3 The reaction liquid of -cyclohexyl-1,3-propylenediamine was sampled for gas chromatography analysis, and the catalyst was left in the reactor for further use. The conversion rate of the intermediate was 100%, N 1-(3-aminopropyl)-N 3 -The yield of cyclohexyl-1,3-propanediamine was 98.13%.

[0085] Repeat the above steps to prepare compound N 1 -(3-aminopropyl)-N 3 -cyclohexyl-1,3-propylenediamine, step 1) using N-(3-aminopropyl)cyclohexylamine, water and N,N-diethylethanolamine, 2) using a catalyst, the results are shown in Table 4:

[0086] Table 4

[0087]

[0088] Example 5

[0089] Preparation of Compound N 1 -(3-aminopropyl)-N 3 -Pure cyclohexyl-1,3-propanediamine:

[0090] The reaction liquid of Example 1 was subjected to vacuum distillation at a vacuum degree of 1 KPa. The fraction with a top temperature of 125° C. was collected. Chromatographic analysis showed that the conversion of acrylonitrile was 100% and the purity of the intermediate was 99.85% (wherein the total content of dinitrile 1 and dinitrile 2 was 0.04 wt%), which was used for the next hydrogenation reaction.

[0091] 2) 12.5 g of Raney nickel catalyst (Grace 2400), 1.25 g of sodium hydroxide (dissolved in water to form a 10 wt% aqueous solution) and 25 g of ethanol were added to the autoclave, and the autoclave was replaced with nitrogen and hydrogen three times in sequence, and then the hydrogen was charged to 3 MPaG, and the temperature was raised. When the reaction temperature rose to 70°C, the hydrogen pressure was increased to 6 MPaG and maintained at this pressure. The intermediate was uniformly added dropwise to the reaction system using a horizontal flow pump. When the feed reached 50 g, the total dropwise addition time was 4 h, the feed was stopped, the reaction was continued for 2 h, the temperature was lowered, and the product containing N 1 -(3-aminopropyl)-N 3 The reaction liquid of -cyclohexyl-1,3-propylenediamine was sampled for gas chromatography analysis, and the catalyst was left in the reactor for further use. The conversion rate of the intermediate was 100%, N 1 -(3-aminopropyl)-N 3 -The yield of cyclohexyl-1,3-propanediamine was 99.61%.

[0092] Comparative Example 1

[0093] Referring to the method in Example 1, the only difference is that: N, N-dimethylethanolamine is not added in step 1), and other parameters and operations remain unchanged to obtain an intermediate, which is sampled for gas chromatography analysis: acrylonitrile conversion is 100%, intermediate selectivity is 97.82%, selectivity of dinitrile 1 is 1.08%, and selectivity of dinitrile 2 is 0.94%.

[0094] The above intermediate was used for hydrogenation reaction according to the method of step 2) of Example 1, and a sample was taken for gas chromatography analysis. The conversion rate of the intermediate was 95.78%, N 1 -(3-aminopropyl)-N 3 -The yield of cyclohexyl-1,3-propanediamine was 90.37%.

[0095] Comparative Example 2

[0096] Referring to the method in Example 1, the only difference is that in step 2), no alkaline modifier potassium hydroxide is added, and other parameters and operations remain unchanged to obtain a product containing N 1 -(3-aminopropyl)-N 3 -cyclohexyl-1,3-propylenediamine reaction solution, sampled for gas chromatography analysis, the conversion rate of the intermediate was 90.45%, N 1 -(3-aminopropyl)-N 3 -The yield of cyclohexyl-1,3-propanediamine was 60.48%.

[0097] Compound N prepared by the present invention 1 -(3-aminopropyl)-N 3 - Cyclohexyl-1,3-propylenediamine performance test, as epoxy resin curing agent, prepared into resin products according to the following formula:

[0098] N 1 -(3-aminopropyl)-N 3 -Cyclohexyl-1,3-propylenediamine and E51 resin were mixed evenly according to the molar number of active hydrogen and epoxy groups, placed in a centrifuge for degassing for 3min@5000r / min, and then poured into a PTFE mold, cured at 80℃ for 2h, and taken out for performance testing.

[0099] The above-prepared resin product was tested for various properties according to the following methods, and the results are shown in Table 5:

[0100] Impact strength: refer to GB / T 1843-2008 Determination of cantilever beam impact strength of plastics;

[0101] Hardness: The product is cured for 24 hours, refer to GB / T 2411-1980 Plastic Shore Hardness Test Method, HTS-800D, Shanghai Yizong Precision Instrument Co., Ltd.

[0102] Yellowing resistance: Use QUV test machine, treat at irradiance of 0.35w / m2@340nm for 24h, and test the color difference change ΔE;

[0103] Glass transition temperature (Tg): DSC test, 10-150°C, heating rate, 5°C / min.

[0104] Table 5

[0105]

[0106] Although the content of the present invention has been described in detail through the above preferred embodiments, it should be appreciated that the above description should not be considered as limiting the present invention. Those skilled in the art will appreciate that, under the guidance of this specification, some modifications or adjustments may be made to the present invention. These modifications or adjustments should also be within the scope defined by the claims of the present invention.

Claims

1. A N 1 -(3-aminopropyl)-N 3 -A method for preparing cyclohexyl-1,3-propylenediamine, characterized in that the steps include: 1) mixing N-(3-aminopropyl)cyclohexylamine, water and an auxiliary agent, then adding acrylonitrile to react, and then subjecting the reaction to vacuum distillation to obtain an intermediate cyanoethylaminopropylcyclohexylamine; 2) mixing the Raney catalyst, the alkaline modifier and the solvent, then introducing hydrogen to adjust the system to the reaction pressure, and heating to the reaction temperature, and then adding the intermediate cyanoethylaminopropylcyclohexylamine obtained in step 1) under a hydrogen atmosphere to carry out a hydrogenation reaction to obtain N 1 -(3-aminopropyl)-N 3 -cyclohexyl-1,3-propanediamine; The auxiliary agent in step 1) is selected from N,N-dimethylethanolamine and / or N,N-diethylethanolamine; the alkaline modifier in step 2) is one or more of lithium hydroxide, sodium hydroxide, potassium hydroxide and ammonia water; the molar ratio of acrylonitrile to N-(3-aminopropyl)cyclohexylamine is 0.8-0.99:

1.

2. The preparation method according to claim 1, characterized in that: The molar ratio of water to N-(3-aminopropyl)cyclohexylamine in step 1) is 0.25-2:

1.

3. The preparation method according to claim 2, characterized in that: The molar ratio of acrylonitrile to N-(3-aminopropyl)cyclohexylamine is 0.9-0.95:

1.

4. The preparation method according to claim 2, characterized in that: The molar ratio of water to N-(3-aminopropyl)cyclohexylamine is 0.5-1:

1.

5. The preparation method according to claim 1, characterized in that: The dosage of the auxiliary agent in step 1) is 5-20wt% of the mass of N-(3-aminopropyl)cyclohexylamine.

6. The preparation method according to claim 5, characterized in that: The dosage of the auxiliary agent is 8-15wt% of the mass of N-(3-aminopropyl)cyclohexylamine.

7. The preparation method according to claim 1, characterized in that: Step 1) The reaction temperature is 10-40°C; the reaction time is 0.2-2h; Step 1) The acrylonitrile is added continuously or dropwise for 2-6 hours, which is not included in the above reaction time; Step 1) The vacuum degree of the vacuum distillation is 0.5-5KPa, and the temperature is 88-150°C.

8. The preparation method according to claim 7, characterized in that: The reaction temperature is 20-30°C; the reaction time is 0.5-1h.

9. The preparation method according to claim 7, characterized in that: The acrylonitrile addition time is 3-4h.

10. The preparation method according to claim 7, characterized in that: The vacuum degree of the reduced pressure distillation is 1-2 KPa, and the temperature is 100-112°C.

11. The preparation method according to claim 1, characterized in that: Step 2) the Raney catalyst is selected from one or more of Raney nickel and Raney cobalt; The amount of the Raney catalyst used is 10-30wt% of the intermediate mass.

12. The preparation method according to claim 11, characterized in that: The Raney catalyst is selected from one or more of Grace 2400, Grace 2800, Grace 2724, Xunkai 1200, and Xunkai 3300.

13. The preparation method according to claim 11, characterized in that: The amount of the Raney catalyst used is 15-25wt% of the intermediate mass.

14. The preparation method according to claim 1, characterized in that: Step 2) the alkaline modifier is selected from one or more of lithium hydroxide and sodium hydroxide; The amount of the alkaline modifier used is 2-20 wt% of the mass of the Raney catalyst.

15. The preparation method according to claim 14, characterized in that: The amount of the alkaline modifier used is 5-10 wt% of the mass of the Raney catalyst.

16. The preparation method according to claim 1, characterized in that: Step 2) the solvent is selected from one or more of methanol, ethanol, tetrahydrofuran, and dioxane; The amount of the solvent used is 0.5-2 times the mass of the intermediate.

17. The preparation method according to claim 16, characterized in that: The amount of the solvent used is 0.75-1.25 times the mass of the intermediate.

18. The preparation method according to claim 1, characterized in that: Step 2) The reaction pressure is 3-8 MPaG; the reaction temperature is 70-140°C; Step 2) the intermediate is continuously added or added dropwise for 2-8 hours; after the addition is completed, the temperature is kept constant for hydrogenation reaction; The reaction time of the hydrogenation reaction in step 2) after the addition of materials is 0.2-2h.

19. The preparation method according to claim 18, characterized in that: The reaction pressure is 4-6 MPaG; the reaction temperature is 80-120°C.

20. The preparation method according to claim 18, characterized in that: The intermediate addition time is 4-6h.

21. The preparation method according to claim 18, characterized in that: The reaction time of the hydrogenation reaction after the addition of materials is 0.4-0.6h.

Images