The invention relates to 3, 3apos; synthetic preparation method of-diaminodipropylamine (DPTA)

Abstract

The invention provides a synthetic preparation method of 3, 3 '-diaminodipropylamine (DPTA), which is efficient, safe, low in cost and easy to industrially amplify. The method is realized through two-step reaction: firstly, preparing 18-22% ammonia water in a water phase system under the conditions that the temperature is controlled to be 40-50 DEG C and the pressure is less than or equal to 0.3 MPa, then dropwise adding acrylonitrile into the ammonia water for reaction under the conditions that the temperature is 60-65 DEG C and the pressure is less than or equal to 0.5 MPa to generate a high-purity DPTAm intermediate, and carrying out rectification dehydration to obtain a dehydrated synthetic liquid containing more than or equal to 95 wt% of DPTAm; then in a hydrogenation reaction, isopropanol is used as a solvent, Raney nickel is used as a catalyst, KOH or NaOH is used as an auxiliary agent, under the guarantee of nitrogen and hydrogen replacement, the DPTAm dehydrated substance is dropwise added at a constant speed for catalytic hydrogenation under the conditions of 80-85 DEG C and 2.2-2.6 MPa, and after the reaction is completed, desolvation, light component removal and rectification purification are performed to obtain the target product DPTA. According to the method, high-selectivity synthesis of DPTAm is achieved, generation of by-products is remarkably reduced, ammonia gas consumption and recovery cost are reduced, meanwhile, the hydrogenation process is optimized, the conversion rate and yield are improved, the DPTA content is larger than or equal to 96%, and the total yield is larger than or equal to 95%. The Raney nickel catalyst can be repeatedly used for more than 50 batches, has stable activity, greatly reduces the production cost, and is suitable for large-scale industrial application.

Description

Technical Field

[0001] This invention relates to a method for synthesizing organic amine compounds, specifically a method for synthesizing 3,3'-diaminodipropylamine (DPTA). Background Technology

[0002] Traditional techniques for preparing diallyltriamine (DPTA) generally employ N-aminopropylation, reduction, and other synthetic methods. These methods suffer from numerous problems, including expensive catalysts, demanding reaction conditions, and low yields, leading to high costs and complex operations. In a previously published paper (MURAHASHIS, YOSHIMURAN, TSUMIYAMAT, et al. Catalytic alkyl group exchange reaction of primary and secondary amines [J]. J Am Chem Soc, 1983, 105(15): 500-5011), MURAHASHIS, YOSHIMURAN, et al. used Pd black as a catalyst to conduct an alkyl exchange reaction of N-heterocyclic butane with three times the amount of 1,3-propanediamine at 170°C under an Ar atmosphere, achieving a DPTA yield of 84%. However, this approach has the following drawbacks: it requires Pd black as a catalyst, which is expensive; and the reaction temperature is very high, reaching 170°C, placing high demands on equipment and energy consumption. The DPTA yield was only 84%, which was low and resulted in low production efficiency.

[0003] Another patent document, application number CN201010141377.0, entitled "A Method for Preparing N-(3-aminopropyl)-1,3-propanediamine," employs a reduction method to prepare DPTA. This method first introduces ammonia and acrylonitrile in a molar ratio of 2:1 into a fixed-bed reactor filled with molecular sieves, reacting at 30°C and 4 MPa for 5 hours to obtain a reactant containing bis(2-cyanoethyl)amine. Then, using KOH or NaOH as the alkali component and Raney Ni as the catalyst, the reactant is catalytically hydrogenated at 70°C and a hydrogen partial pressure of 2 MPa, ultimately yielding DPTA in 88.5% yield. However, this method also has the following drawbacks: 1. The preparation of bis(2-cyanoethyl)amine requires a complex fixed-bed reactor, increasing equipment investment and operational difficulty. 2. The reaction pressure is as high as 4 MPa, which is considered ultra-high reaction pressure, placing extremely high demands on the safety and pressure resistance of the equipment. 3. The reaction time is as long as 5 hours, which is too long and reduces production efficiency. 4. The final yield after hydrogenation is only 88.5%, which, although slightly higher than the N-aminopropylation method, is still low and fails to reach the ideal yield level. 5. In summary, existing DPTA preparation methods generally suffer from high catalyst costs, harsh reaction conditions, and low yields. There is an urgent need to develop new preparation methods to overcome these shortcomings and improve the efficiency and economy of DPTA preparation. Summary of the Invention

[0004] This invention aims to overcome the aforementioned shortcomings of the prior art and provide a highly efficient, safe, low-cost, and easily industrially scalable method for the synthesis and preparation of 3,3'-diaminodipropylamine (DPTA). To solve the above technical problems, the technical solution adopted by this invention is as follows: A method for synthesizing 3,3'-diaminodipropylamine (DPTA) includes the following steps: Step 1: In a system using water as a solvent, after nitrogen purging, 100 parts by weight of ammonia gas are introduced. Ammonia gas is introduced into the water solvent system and the temperature is controlled at 40-50℃ and the pressure is ≤0.3MPa to prepare ammonia water with a concentration of 18-22%. The amount of water is adjusted according to the required concentration, usually 345-555 parts by weight, to ensure that the ammonia water concentration is stable and conducive to the selectivity of subsequent reactions. Step two: Acrylonitrile is added at a rate of 625–640 parts by weight over a dropping time of 2–4 hours. The reaction temperature is maintained at 60–65°C, and the pressure is ≤0.5 MPa. After the dropping is complete, the reaction is maintained at this temperature for 1–1.5 hours until GC analysis shows a DPTAM content ≥97% and a DAPm byproduct ≤0.5%, meeting the discharge standard. The DPTAM synthesis solution is then distilled to remove water, yielding a dehydrated synthesis solution. This dehydrated solution is used in subsequent hydrogenation reactions and contains at least 97 wt% effective DPTAM. Step 3: Weigh 700–900 parts by weight of isopropanol, 60–75 parts by weight of Raney nickel, and 4.0–4.8 parts by weight of additive KOH or NaOH, turn on the stirrer, and add all of them into the hydrogenation autoclave. Step 4: Before adding hydrogen, nitrogen purging must be performed at least 3 times, followed by hydrogen purging 3–5 times to ensure that the oxygen content in the system is below the safety limit; during the preheating stage, hydrogen is charged to 1.0–1.2 MPa, the stirring frequency is increased to 20–25 Hz, and the temperature is heated to 70–75°C; after the system stabilizes, the stirring frequency is increased to 38 Hz, the pressure is increased to 2.0–2.6 MPa, and 700–720 parts by weight of DPTAM dehydration product are added dropwise. During the dropwise addition, the reaction temperature is strictly controlled within the range of 80–85°C. Step 5: After DPTAm is added, take a sample for GC analysis. The synthesis solution must be completely converted to obtain the DPTA product.

[0005] Preferably, the amount of isopropanol used is 780–880 parts by weight.

[0006] Preferably, the DPTAm dehydrated material is added to the reaction system at a constant rate over 2 hours using a metering pump. The dropping rate is controllable to avoid violent exothermic reactions. If necessary, external cooling is used to maintain a constant temperature.

[0007] Preferably, in step five, after DPTAm is added, the system is allowed to cool naturally or the temperature is finely adjusted, and the reaction is continued with stirring for more than 1 hour. Samples are then taken for GC detection, requiring complete conversion of DPTAm and a DPTA content of ≥96% in the target product. If the standard is not met, the reaction time is extended or the temperature is finely adjusted until it meets the standard.

[0008] Preferably, after the hydrogenation is completed, the reaction solution is subjected to vacuum distillation to remove isopropanol and light components, and then purified by molecular distillation or vacuum distillation to obtain a high-purity DPTA product with a yield ≥96% (based on DPTAm), meeting the requirements for electronic or polymeric applications.

[0009] Preferably, the Raney nickel catalyst can be reused after filtration and recovery, with a reuse count of more than 50 batches and an activity decrease of no more than 3% per batch. The reaction efficiency can be maintained by adding a small amount of new catalyst.

[0010] The beneficial effects of this invention are as follows: 1. This invention provides a highly efficient, safe, low-cost, and easily scalable method for the synthesis of 3,3'-diaminodipropylamine (DPTA). This method achieves highly selective synthesis of DPTAm, significantly reduces byproduct formation, lowers ammonia consumption and recovery costs, and optimizes the hydrogenation process, improving conversion and yield (≥95%). The Raney nickel catalyst can be reused more than 50 times, exhibits stable activity, and significantly reduces production costs, making it suitable for large-scale industrial applications.

[0011] 2. DPTAm Synthesis: This method efficiently and selectively directs the reaction of ammonia and acrylonitrile to produce DPTAm, significantly reducing the 1:1 and 1:3 reaction products between ammonia and acrylonitrile. Excess ammonia is virtually eliminated, greatly reducing ammonia recovery and waste. It also lowers reaction conditions (reaction temperature and pressure), making the reaction more controllable and safer, and shortening the reaction time.

[0012] 3. DPTA hydrogenation: DPTA is prepared by hydrogenation reaction, which reduces the amount of solvent used, reduces the amount of catalyst used, and increases the number of catalyst reuse batches; 4. The use of the dropwise addition method for hydrogenation reaction greatly improves the hydrogenation yield and the stability of the hydrogenation reaction. Attached Figure Description

[0013] Figure 1 This is the DPTAm synthesis-GC spectrum; Figure 2 This is the GC spectrum of a DPTA product. Detailed Implementation

[0014] The specific embodiments of the present invention are as follows.

[0015] I. Example 1 Step 1: In a system with water as the solvent, after nitrogen purging, 100 parts by weight of ammonia gas are introduced. Ammonia gas is introduced into the water solvent system and the temperature is controlled at 40℃ and the pressure is ≤0.3MPa to prepare ammonia water with a concentration of 18%; the amount of water is 555 parts by weight to ensure that the ammonia water concentration is stable and conducive to the selectivity of subsequent reactions.

[0016] Step 2: The amount of acrylonitrile added is 625 parts by weight, the dropping time is 2 hours, the reaction temperature is maintained at 60℃, the pressure is ≤0.5MPa, and the reaction is kept at this temperature for 1 hour after the dropping is completed, until GC detection shows that the DPTAm content is ≥97% and the by-product DAPm is ≤0.5%; the DPTAm synthesis liquid is purified by distillation to remove water to obtain a dehydrated synthesis liquid containing no less than 97wt% effective DPTAm component.

[0017] Step 3: Weigh 700 parts by weight of isopropanol, 60 parts by weight of Raney nickel, and 4.0 parts by weight of KOH, turn on the stirrer, and add all of them into the hydrogenation autoclave.

[0018] Step 4: Before adding hydrogen, purge with nitrogen three times, then purge with hydrogen three times; during the preheating stage, purge with hydrogen to 1.0 MPa, increase the stirring frequency to 20 Hz, and heat to 70°C; after the system stabilizes, increase the stirring frequency to 38 Hz and the pressure to 2.0 MPa, and add 700 parts by weight of DPTAm dehydrated product dropwise at a uniform rate over 2 hours using a metering pump, strictly controlling the reaction temperature at 80°C during the dropwise addition process.

[0019] Step 5: After the DPTAm was added, the system was allowed to cool naturally, and the reaction was continued with stirring for 1.5 hours. GC analysis of the sample showed that the DPTAm was completely converted and the DPTA content was ≥96%. The reaction solution was subjected to vacuum distillation to remove isopropanol and light components, and then purified by molecular distillation to obtain a high-purity DPTA product with a yield of 96.2% (based on DPTAm). The Raney nickel catalyst was filtered and recovered for reuse. After 50 batches, the activity still maintained 97.1% of the initial value.

[0020] II. Example 2 Step 1: In a system with water as the solvent, after nitrogen purging, 100 parts by weight of ammonia gas are introduced. Ammonia gas is introduced into the water solvent system and the temperature is controlled at 45℃ and the pressure is ≤0.3MPa to prepare ammonia water with a concentration of 20%; the amount of water is 450 parts by weight to ensure that the ammonia water concentration is stable and conducive to the selectivity of subsequent reactions.

[0021] Step 2: The amount of acrylonitrile added is 632.5 parts by weight, the dropping time is 3 hours, the reaction temperature is maintained at 62.5℃, the pressure is ≤0.5MPa, and after the dropping is completed, the reaction is kept at this temperature for 1.25 hours until GC detection shows that the DPTAm content is ≥97% and the byproduct DAPm is ≤0.5%; the DPTAm synthesis solution is purified by distillation to remove water to obtain a dehydrated synthesis solution containing no less than 97wt% effective DPTAm component.

[0022] Step 3: Weigh 780 parts by weight of isopropanol, 67.5 parts by weight of Raney nickel, and 4.4 parts by weight of NaOH, turn on the stirrer, and add all of them into the hydrogenation autoclave.

[0023] Step 4: Before adding hydrogen, purge with nitrogen three times, then purge with hydrogen four times; during the preheating stage, purge with hydrogen to 1.1 MPa, increase the stirring frequency to 22.5 Hz, and heat to 72.5 °C; after the system stabilizes, increase the stirring frequency to 38 Hz and the pressure to 2.3 MPa, and add 710 parts by weight of DPTAM dehydrated product dropwise at a uniform rate over 2 hours using a metering pump, strictly controlling the reaction temperature at 82.5 °C during the dropwise addition process.

[0024] Step 5: After the DPTAm was added, the system was allowed to cool naturally, and the reaction was continued with stirring for 1 hour. GC testing of the sample showed that DPTAm was completely converted and the DPTA content was ≥96%. The reaction solution was subjected to vacuum distillation to remove isopropanol and light components, and then purified by vacuum distillation to obtain a high-purity DPTA product with a yield of 96.8% (based on DPTAm). The Raney nickel catalyst was filtered and recovered for reuse. After 50 batches, the activity still maintained 97.4% of the initial value.

[0025] III. Example 3 Step 1: In a system with water as the solvent, after nitrogen purging, 100 parts by weight of ammonia gas are introduced. Ammonia gas is introduced into the water solvent system and the temperature is controlled at 50℃ and the pressure is ≤0.3MPa to prepare ammonia water with a concentration of 22%; the amount of water is 345 parts by weight to ensure that the ammonia water concentration is stable and conducive to the selectivity of subsequent reactions.

[0026] Step 2: The amount of acrylonitrile added is 640 parts by weight, the dripping time is 4 hours, the reaction temperature is maintained at 65℃, the pressure is ≤0.5MPa, and the reaction is kept at this temperature for 1.5 hours after the dripping is completed, until GC detection shows that the DPTAm content is ≥97% and the by-product DAPm is ≤0.5%; the DPTAm synthesis solution is purified by distillation to remove water to obtain a dehydrated synthesis solution containing no less than 97wt% effective DPTAm component.

[0027] Step 3: Weigh 900 parts by weight of isopropanol, 75 parts by weight of Raney nickel, and 4.8 parts by weight of KOH, turn on the stirrer, and add all of them into the hydrogenation autoclave.

[0028] Step 4: Before adding hydrogen, purge with nitrogen 3 times, then purge with hydrogen 5 times; during the preheating stage, purge with hydrogen to 1.2 MPa, increase the stirring frequency to 25 Hz, and heat to 75 ℃; after the system stabilizes, increase the stirring frequency to 38 Hz and the pressure to 2.6 MPa, and add 720 parts by weight of DPTAm dehydrated product dropwise at a uniform rate over 2 hours using a metering pump, strictly controlling the reaction temperature at 85 ℃ during the dropwise addition process.

[0029] Step 5: After the DPTAm was added, the system was allowed to cool naturally, and the reaction was continued with stirring for 1 hour. GC analysis of the sample showed that DPTAm was completely converted and the DPTA content was ≥96%. The reaction solution was subjected to vacuum distillation to remove isopropanol and light components, and then purified by molecular distillation to obtain a high-purity DPTA product with a yield of 97.1% (based on DPTAm). The Raney nickel catalyst was filtered and recovered for reuse. After 50 batches, the activity still maintained 97.0% of the initial value.

[0030] Comparative Example 1: This comparative example provides a method for synthesizing 3,3'-diaminodipropylamine (DPTA), characterized by the following parameters exceeding the range of the examples: Step 1, in a system with water as the solvent, 100 parts by weight of ammonia gas are introduced, but the reaction temperature is 55°C (below 60°C), the pressure is 0.6 MPa (above 0.5 MPa), and the amount of water is 600 parts by weight, resulting in an ammonia concentration of 15% (below 18%); Step 2, the amount of acrylonitrile added is 650 parts by weight (above 640), the dropping time is 1.5 hours (less than 2 hours), the reaction temperature is 70°C (above 65°C), the pressure is 0.9 MPa (above 0.8 MPa), and the reaction time is maintained at this temperature for 0.8 hours (less than 1 hour). GC analysis showed that the DPTAM content was 94.1% and the DAPm content of the byproduct was 1.2%. In step three, 950 parts by weight of isopropanol (above 900), 50 parts by weight of Raney nickel (below 60), and 3.5 parts by weight of KOH or NaOH (below 4.0) were weighed and added to the hydrogenation reactor. In step four, nitrogen purging was performed only twice, and hydrogen purging was performed twice, resulting in insufficient removal of oxygen from the system. The system was preheated and charged with hydrogen to 0.8 MPa (below 1.0 MPa), with a stirring frequency of 18 Hz (below 20 Hz) and heated to 65°C (below 70°C). When adding the DPTAM dehydrated product, the stirring frequency was 30 Hz (below 38 Hz), the pressure was 2.0 MPa (below 2.2 MPa), and the reaction temperature was controlled at 88°C (above 85°C), leading to localized and intense exothermic reactions. In step five, after the addition was completed, the reaction was kept at the temperature for only 30 minutes. GC analysis of the sample showed that the DPTAM conversion rate was 90.3% and the DPTA content was 91.5%, which did not meet the standards. The final product yield was 88.7% after purification. Table 1: Comparison of key parameters and results between Example 2 and Comparative Example 1

[0031]

[0032] A comparison between Comparative Example 1 and Example 2 shows that when reaction parameters deviate from the limits defined in this invention, factors such as insufficient ammonia concentration, excessively rapid dropping acceleration, excessively high hydrogenation temperature, or insufficient pressure can all lead to incomplete synthesis of the intermediate DPTAm, increased byproducts, decreased hydrogenation reaction conversion rate, and a significant reduction in the purity and yield of the final product. This invention ensures the high efficiency and stability of the reaction by precisely controlling the parameter ranges of each step.

[0033] Comparative Example 2: This comparative example provides a method for synthesizing DPTA, in which some raw materials are replaced: Steps one and two are the same as in Example 1, yielding 710 parts by weight of DPTAM dehydrated liquid containing 96.0 wt% DPTAM; Step three, isopropanol is replaced with 900 parts by weight of ethanol, and the auxiliary agent KOH is maintained at 4.0 parts by weight, and added to a hydrogenation autoclave; Step four, nitrogen is purged three times and hydrogen is purged four times, ensuring the system oxygen content is within acceptable limits; preheating and hydrogen charging to 1.1 MPa, stirring frequency 22.5 Hz, heating to 72.5 °C; after stabilization, stirring frequency is increased to 38 Hz, pressure is increased to 2.4 MPa, and DPTAM dehydrated product is added dropwise, controlling the temperature at 82.5 °C; Step five, after the dropwise addition is completed, the reaction is maintained at this temperature for 1.2 hours. GC analysis of the sample shows that the DPTAM conversion rate is 90.2%, the DPTA content is 89.7%, and there are many intermediate residues. The final product yield is 83.3%, and the palladium-on-carbon catalyst is expensive, difficult to recycle and reuse, and exhibits large batch-to-batch activity fluctuations. Table 2: Comparison of material substitutions between Example 1 and Comparative Example 2:

[0034]

[0035] Comparison Example 2 with Example 1 shows that although the basic reaction pathway is feasible after replacing isopropanol with ethanol, the difference in solvent polarity and catalyst activity leads to a decrease in reaction efficiency, a reduction in product purity, and difficulty in catalyst recovery, significantly increasing production costs. This invention uses an isopropanol / Raney nickel / KOH or NaOH combination system, which has good compatibility, high catalytic activity, and excellent recyclability, making it suitable for continuous industrial production.

[0036] Comparative Example 3: This comparative example provides a method for synthesizing DPTA, in which some raw materials are replaced: Steps one to five are the same as in Example 2, yielding 710 parts by weight of dehydrated DPTAm containing 96.0 wt% DPTAm. Replacing Raney nickel with 50 parts by weight of palladium on carbon catalyst (Pd / C, 5% loading), GC analysis showed a DPTAm conversion rate of 92.6% and a DPTA content of 93.1%, with significant intermediate residues. The final product yield was 90.2%, and the palladium on carbon catalyst is costly, difficult to recycle and reuse, and exhibits large batch-to-batch activity fluctuations. Table 3: Comparison of material substitutions between Example 2 and Comparative Example 3:

[0037]

[0038] Comparison Example 3 with Example 2 shows that although the basic reaction pathway is feasible after replacing Raney nickel with palladium on carbon, the difference in solvent polarity and catalyst activity leads to a decrease in reaction efficiency, a reduction in product purity, and difficulty in catalyst recovery, significantly increasing production costs. This invention uses an isopropanol / Raney nickel / KOH or NaOH combination system, which has good compatibility, high catalytic activity, and excellent recyclability, making it suitable for continuous industrial production.

[0039] Comparative Example 4: This comparative example provides a method for synthesizing DPTA, with process steps different from Example 2: Steps one and two are the same as in Example 2, yielding 710 parts by weight of DPTAm dehydrated liquid; Step three, weighing 830 parts by weight of isopropanol, 67.5 parts by weight of Raney nickel, and 4.4 parts by weight of KOH or NaOH, and adding them to a hydrogenation reactor; Step four, omitting the nitrogen and hydrogen replacement steps, directly charging with hydrogen to 2.4 MPa, heating to 72.5°C, increasing the stirring frequency to 38 Hz, and starting the dropwise addition of DPTAm dehydrated product; Step five, during the dropwise addition process, a local oxidation reaction was triggered by residual air in the system, causing the temperature to rise sharply to 95°C, posing a risk of material overflow, and emergency cooling was performed. After the reaction, samples were taken for testing, showing a DPTAm conversion rate of 89.7%, a DPTA content of 90.8%, and an increase in by-products. The final product yield was 87.5%, and the catalyst was partially deactivated and could not be recycled.

[0040] In summary, the technical solution provided by this invention has significant advantages in reaction condition control, raw material selection, and process design, and can stably obtain high-purity, high-yield DPTA products to meet the requirements of electronic or polymeric applications.

Claims

1. A method for the synthetic preparation of 3,3'-diaminodipropylamine (DPTA) characterized by: The method comprises the following steps: Step 1: in a system with water as a solvent, after nitrogen replacement, 100 parts by weight of ammonia gas is introduced into the water solvent system, and the temperature is controlled at 40-50 DEG C, and the pressure is less than or equal to 0.3 MPa, to prepare ammonia water with a concentration of 18-22%; the amount of water is 345-555 parts by weight; Step 2: the amount of acrylonitrile is 625-640 parts by weight, the dropping time is 2-4 hours, the reaction temperature is maintained at 60-65 DEG C, the pressure is less than or equal to 0.5 MPa, and after the dropping is completed, the reaction is maintained for 1-1.5 hours, until the GC detection shows that the content of DPTAm is greater than or equal to 97%, and the by-product DAPm is less than or equal to 0.5%; the DPTAm synthesis solution is subjected to rectification to remove water to obtain a dehydrated synthesis solution, and the dehydrated substance contains DPTAm effective ingredient in an amount of not less than 97 wt%; Step 3: 700-900 parts by weight of isopropyl alcohol, 60-75 parts by weight of Raney nickel, and 4.0-4.8 parts by weight of an auxiliary agent KOH or NaOH are weighed, and stirring is started, and all are added into a hydrogenation autoclave; Step 4: before hydrogenation, nitrogen is replaced more than 3 times, and then hydrogen is replaced 3-5 times; in the preheating stage, hydrogen is filled to 1.0-1.2 MPa, the stirring frequency is increased to 20-25 Hz, and heating is started to 70-75 DEG C; after the system is stabilized, the stirring is increased to 38 Hz, the pressure is increased to 2.0-2.6 MPa, and 700-720 parts by weight of DPTAm dehydrated substance is started to be added dropwise, and the reaction temperature is strictly controlled in the range of 80-85 DEG C during the dropping process; Step 5: after the DPTAm is added dropwise, sampling is performed for GC detection, and it is required that DPTAm is completely converted to obtain DPTA product.

2. The process for the synthesis of 3,3'-diaminodipropylamine (DPTA) according to claim 1, characterized by the fact that: The amount of isopropyl alcohol is 780-880 parts by weight.

3. The process for the synthesis of 3,3'-diaminodipropylamine (DPTA) according to claim 1, characterized by the fact that: The DPTAm dehydrated substance is added into the reaction system at a uniform speed by a metering pump within 2 hours.

4. The process for the synthesis of 3,3'-diaminodipropylamine (DPTA) according to claim 1, characterized by the fact that: In step 5, after the DPTAm is added dropwise, the stirring reaction is continued for more than 1 hour, sampling is performed for GC detection, and it is required that DPTAm is completely converted, and the content of target product DPTA is greater than or equal to 96%; if it does not meet the standard, the reaction time is extended or the temperature is adjusted to the qualified standard.

5. The process for the synthesis of 3,3'-diaminodipropylamine (DPTA) according to claim 1, characterized by the fact that: After the hydrogenation is completed, the reaction liquid is subjected to reduced pressure distillation to remove isopropyl alcohol and light components, and then purified by molecular distillation or vacuum rectification to obtain high-purity DPTA product, and the yield is greater than or equal to 96% (based on DPTAm).

6. The process for the synthesis of 3,3'-diaminodipropylamine (DPTA) according to claim 1, characterized by the fact that: The Raney nickel catalyst can be reused after filtration and recovery, and the reuse number is more than 50 batches, and the activity is decreased by not more than 3% per batch, and the reaction efficiency is maintained by adding a small amount of new catalyst.

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