Method for preparing dipropylenetriamine from VB1 process aminopropionitrile rectified high-boiling oil through catalytic hydrogenation

Abstract

Aminopropionitrile rectified high-boiling oil generated in an aminopropionitrile preparation section when acrylonitrile is used as a raw material to produce VB1 is subjected to reduced pressure rectification or in-situ catalytic cracking reduced pressure reaction rectification, so that dicyanoethylamine distillate with the mass percentage content of dicyanoethylamine greater than 97% is obtained at the yield of 75% or more relative to the mass of the aminopropionitrile rectified high-boiling oil. The method comprises the following steps: dissolving dicyanoethylamine distillate with an organic solvent, and carrying out catalytic hydrogenation under an alkaline condition in the presence of a catalyst to obtain a hydride material containing dipropylenetriamine. The method comprises the following steps: separating a catalyst from a hydride material containing dipropylenetriamine through centrifugation or filtration, recovering an organic solvent in the hydride material through distillation, carrying out reduced pressure rectification, and carrying out rectification fraction collection according to a relational expression t = 92.42 + 9.645 / (1.573-lgP) between a boiling point t (DEG C) of the material and a corresponding external pressure P (mmHg) so as to obtain a dipropylenetriamine product with a mass percentage of more than 97%.

Description

Technical Field

[0001] This invention belongs to the field of environmental protection and comprehensive resource utilization technology, and relates to a method for preparing dipropylenetriamine by distilling high-boiling oil of aminopropionitrile produced in the chemical production process of VB1 using acrylonitrile as the starting material. Background Technology

[0002] Vitamin B1, chemically named 3-[(4-amino-2-methyl-5-pyrimidinyl)-methyl]-5-(2-hydroxyethyl)-4-methylthiazolyl hydrochloride, also known as vitamin B1, thiamine, anti-neuritis factor, and anti-beriberi factor, is a water-soluble white crystalline or crystalline powder found naturally in foods such as rice bran, wheat bran, lean meat, and nuts. As a feed additive, vitamin B1 plays an important role in maintaining normal nerve conduction and the normal functioning of the heart and digestive system in livestock and poultry. As a medicine, vitamin B1 maintains normal glucose metabolism and nerve conduction, and inhibits cholinesterase activity, making it useful as an adjunct treatment for indigestion, neuritis, and beriberi.

[0003] The large-scale industrial production of VB1 mainly relies on chemical methods, involving both convergent and linear routes, with the linear route being the primary method for industrial VB1 production. In the linear route for VB1 production, 2-methyl-4-amino-5-(aminomethyl)pyrimidine is the core intermediate. Depending on the starting materials used, the preparation of 2-methyl-4-amino-5-(aminomethyl)pyrimidine can be achieved via acrylonitrile, malononitrile, or cyanoacetamide routes, with the acrylonitrile route being the most widely used in industrial production. In the acrylonitrile route for preparing 2-methyl-4-amino-5-(aminomethyl)pyrimidine, the initial step involves the reaction of acrylonitrile with ammonia to produce a material containing 3-aminopropionitrile (abbreviated as aminopropionitrile). This material is then distilled to obtain high-purity aminopropionitrile with a relatively low boiling point. The high-boiling-point residue produced during this distillation process is the aminopropionitrile distillate high-boiling oil. In the existing process for producing VB1 based on acrylonitrile as the starting material, the resulting high-boiling oil from aminopropionitrile distillation is classified as hazardous waste and mainly relies on high-temperature incineration to achieve its harmlessness. Although this treatment method can reduce the environmental harm caused by the direct emission of high-boiling oil from aminopropionitrile distillation, it does not achieve the full and effective utilization of resources.

[0004] Dipropylenetriamine, also known as bis(3-aminopropyl)amine, 3,3′-diaminodipropylamine, or dipropylenetriamine, is an organic polyamine. It can be used directly as a curing agent for epoxy resins, or as a basic raw material in the preparation of other types of epoxy resin curing agents. Furthermore, it can serve as an intermediate in the synthesis of surfactants, adsorption and separation materials, corrosion inhibitors, antistatic agents, fiber softeners, functional polymers, agrochemicals, and pharmaceuticals.

[0005] As an organic nitrogen-containing compound possessing both primary and secondary amine structures, diallyltriamine is mainly prepared through two methods: the N-aminopropylation method based on 1,3-propanediamine and the reduction method based on bis(2-cyanoethyl)amine (abbreviated as dicyanethylamine). Additionally, diallyltriamine can also be partially obtained by reducing 3,3′,3′-nitrotripropamide, the addition product of ammonia and acrylamide, with LiAlH4, and by reacting 1,3-propanediol with ammonia in the presence of a catalyst. Among these methods for preparing diallyltriamine, the reduction method based on dicyanethylamine is more widely used in actual production.

[0006] This invention relates to a method for preparing dipropylenetriamine using high-boiling oil from the distillation of aminopropionitrile produced in the VB1 production process. This method belongs to a technical approach for preparing fine organic chemicals from pharmaceutical industrial waste. During the research and development of this technology, numerous technical documents related to the preparation and application of VB1, dicyandiethylamine, and dipropylenetriamine were consulted. Among these, the following documents are of significant reference value: "Synthesis of 2-Methyl-4-amino-5-carboxamide methylpyrimidine" (Applied Chemical Industry, 2005, Vol. 34, No. 3), "An Eight-Step Continuous-Flow Total Synthesis of Vitamin B1" (Engineering, 2024, Vol. 32), "Research Progress in Vitamin B1 Synthesis" (Zhejiang Chemical Industry, 2015, Vol. 46, No. 6), and "Method for producing bis[3-(dimethylamino)propyl]amine (dipropylenetriamine, DPTA)" (US 20080132725). A1, 2008-06-05), "A Method for Preparing N-(3-aminopropyl)-1,3-propanediamine" (CN101817753A, 2010-09-01), "Cobalt-Catalyzed Amination of 1,3-Propanediol: Effects of Catalyst Promotion and Use of Supereritical Ammonia as Solvent and Reactant" (Journal of Catalysis, 1999, Vol.183, No.).2) "Multifunctional primary amine, process for its preparation, and use in curing coatings" (WO2012150312 A1, 2012-11-08); "Ethoxylated fatty amines and similar nitrogen-containing compounds as corrosion inhibitors for petroleum-field applications" (WO2003054251A2, 2003-07-03); "Development of a production process for tallow-based dipropylenetriamine" (East China University of Science and Technology, 2011); "Catalytic alkyl group exchange reaction of primary and secondary amines" (Journal of the American Chemical Society, 1983, Vol.105, No.15); "A facile synthesis of intermediate of the bicyclic organic bases DBU and TBD" (Synthetic Communications, 1993, Vol.23, No.22). Summary of the Invention

[0007] Technical Problems Solved: This application discloses a method for preparing diallyltriamine from aminopropionitrile distillation high-boiling oil produced in the VB1 process via catalytic hydrogenation. The main technical problems solved are threefold: first, to achieve the scientific disposal and high-value utilization of the aminopropionitrile distillation high-boiling oil generated in existing chemical processes for producing VB1 using acrylonitrile as a raw material; second, to reduce the dependence on 1,3-propanediamine or acrylonitrile in existing large-scale industrial production of diallyltriamine; and third, to reduce the raw material costs for producing diallyltriamine. This invention, utilizing aminopropionitrile distillation high-boiling oil generated in the VB1 process, can promote the greening of existing VB1 production processes based on acrylonitrile as one of the raw materials, facilitate efficient resource utilization, and make the production of VB1 and diallyltriamine more in line with the requirements of "energy saving, emission reduction, consumption reduction, and high efficiency."

[0008] Technical solution:

[0009] A method for preparing diallyltriamine from high-boiling oil of aminopropionitrile distillation in the VB1 process via catalytic hydrogenation is as follows: First, the high-boiling oil of aminopropionitrile distillation produced in the aminopropionitrile preparation section during the production of VB1 using acrylonitrile as raw material is distilled or subjected to in-situ catalytic cracking distillation to remove polymers or convert some polymers into smaller molecule compounds, and a dicyandiethylamine distillate with a dicyandiethylamine content greater than 97% by mass is obtained at a yield of more than 75% relative to the mass of the high-boiling oil of aminopropionitrile distillation; Second, the dicyandiethylamine distillate is dissolved in an organic solvent and then catalytically hydrogenated under alkaline conditions and in the presence of a catalyst to obtain a hydrogenated material containing diallyltriamine; Third, the obtained hydrogenated material containing diallyltriamine is centrifuged or filtered to separate the catalyst and then distilled to recover the organic solvent; Finally, the hydrogenated material containing diallyltriamine with the recovered organic solvent is subjected to vacuum distillation to obtain a diallyltriamine product with a dicyandiethylamine content greater than 97% by mass.

[0010] Preferably, the distillation or in-situ catalytic cracking reaction distillation for the high-boiling oil of aminopropionitrile is carried out under reduced pressure, and the distillate is collected according to the relationship between the boiling point t (°C) of the material and the corresponding external pressure P (mmHg) by formula t = 94.76 + 107.26 / (2.731 - lgP) to obtain dicyandiethylamine distillate.

[0011] Preferably, the catalyst used for in-situ catalytic cracking of high-boiling oil in aminopropionitrile distillation is a siloxy-supported acid catalyst with a mixture of one or more of zeolite, silica gel and molecular sieve in proportion as the support and phosphoric acid / silicic acid / phosphotungstic acid / silicotungstic acid and / or phosphosilicate as the active components.

[0012] Preferably, the organic solvent used to dissolve the dicyandiethylamine distillate obtained by vacuum distillation or in-situ catalytic cracking of high-boiling oil obtained by distillation under reduced pressure is a mixture of one or more of methanol, ethanol, dioxane, benzene, toluene and petroleum ether in proportion.

[0013] Preferably, the substance used to provide alkaline conditions for the catalytic hydrogenation of dicyandiethylamine distillate obtained by vacuum distillation or in-situ catalytic cracking of high-boiling oil obtained by high-boiling oil from aminopropionitrile distillation is one or a mixture of several of NH3, NaOH, KOH, Ca(OH)2, Na2CO3 and K2CO3 in proportion.

[0014] Preferably, the catalyst used for the catalytic hydrogenation of dicyandiethylamine distillate obtained by vacuum distillation or in-situ catalytic cracking of high-boiling oil obtained by high-boiling oil distillation of aminopropionitrile is a mixture of one or more of the following in proportion: diatomaceous earth-supported elemental Ni, alumina-supported elemental Ni, Raney Ni, PtO2, and Pd / C.

[0015] Preferably, the hydrogenated material containing diallyltriamine, after the organic solvent has been recovered, is subjected to vacuum distillation, and the distillate is collected according to the relationship between the boiling point t (°C) of the material and the corresponding external pressure P (mmHg) t = 92.42 + 9.645 / (1.573 - lgP), thereby obtaining a diallyltriamine product with a mass percentage content greater than 97%.

[0016] Preferably, the method for preparing dipropylenetriamine from high-boiling oil obtained by catalytic hydrogenation of aminopropionitrile distillation using the VB1 process comprises the following steps:

[0017] Step 1: Under continuous stirring, the high-boiling oil of aminopropionitrile is subjected to vacuum distillation or in-situ catalytic cracking vacuum distillation. The distillation liquid fraction under the corresponding external pressure is collected according to the relationship between the boiling point t (°C) of the material and the corresponding external pressure P (mmHg) t=94.76+107.26 / (2.731-lgP) to obtain the dicyandiethylamine distillate with polymers removed.

[0018] Step 2: Dissolve the dicyandiethylamine distillate in a solvent consisting of one or more of methanol, ethanol, dioxane, benzene, toluene and petroleum ether in a certain proportion, and then add a mixture consisting of one or more of NH3, NaOH, KOH, Ca(OH)2, Na2CO3 and K2CO3 in a certain proportion to make the pH of the material greater than 10.

[0019] Step 3: Add one or more of the following in proportion to the alkaline organic mixture containing dicyandiethylamine that has been pH adjusted: diatomaceous earth-supported elemental Ni, alumina-supported elemental Ni, Raney Ni, PtO2, and Pd / C. Then, introduce N2 or ammonia to replace the air in the reactor.

[0020] Step 4: Start the stirring device and introduce H2 into the air-purified reactor until the pressure on the reactor gauge is 0.1–8.0 MPa;

[0021] Step 5: Turn on the heating control device and heat the material in the reactor. Then, under the condition of continuous H2 introduction and controlling the material temperature at 50-150℃, react for 4-24 hours to obtain hydrogenated material.

[0022] Step 6: Cool the hydrogenated material obtained in Step 5 until the material temperature is below 40°C, and then filter or centrifuge it under N2 protection to obtain the hydrogenated material with the catalyst removed.

[0023] Step 7: The hydrogenated material after the catalyst has been removed is subjected to atmospheric distillation to recover the solvent and obtain concentrated hydrogenated material. The recovered solvent can partially replace the solvent in Step 2 for dissolving the dicyandiethylamine distillate.

[0024] Step 8: The concentrated hydrogenated material obtained in Step 7 is subjected to vacuum distillation, and the distillate fraction is collected according to the relationship between the boiling point t (°C) of the material and the corresponding external pressure P (mmHg) t = 92.42 + 9.645 / (1.573 - lgP) to obtain a dipropylenetriamine product with a mass percentage content greater than 97%.

[0025] Beneficial effects:

[0026] 1. Using the aminopropionitrile distillation high-boiling oil formed in the VB1 production process with acrylonitrile as one of the basic raw materials to prepare diallyltriamine can achieve more efficient scientific treatment of aminopropionitrile distillation high-boiling oil and improve the high-value effective utilization rate of resources.

[0027] 2. Using the aminopropionitrile distillation high-boiling oil formed in the VB1 production process with acrylonitrile as one of the basic raw materials to prepare diallyltriamine can reduce the dependence on 1,3-propanediamine or acrylonitrile in the existing industrial-scale production of diallyltriamine.

[0028] 3. Using the aminopropionitrile distillation high-boiling oil formed in the VB1 production process with acrylonitrile as one of the basic raw materials to prepare diallyltriamine is conducive to reducing the raw material cost of diallyltriamine production and promoting the clean production and greening of VB1 and diallyltriamine production processes. Attached Figure Description

[0029] Figure 1 distillate of dicyandiethylamine 1 1H NMR spectrum (CDCl3 as solvent);

[0030] Figure 2 For dipropylenetriamine products 1 1H NMR spectrum (CDCl3 is the solvent). Detailed Implementation

[0031] The following embodiments are provided to enable those skilled in the art to more fully understand the present invention, but do not limit the invention in any way.

[0032] Example 1

[0033] A method for preparing diallyltriamine from high-boiling oil obtained by catalytic hydrogenation of aminopropionitrile distillation using the VB1 process includes the following steps:

[0034] Step 1: The high-boiling oil of aminopropionitrile is subjected to vacuum distillation, and the liquid fraction of distillation at 156-157℃ / 10mmHg is collected to obtain a dicyandiethylamine distillate with a mass percentage of 98.2% at a yield of 76.5% relative to the mass of the high-boiling oil of aminopropionitrile.

[0035] Step 2: Dissolve the dicyandiethylamine distillate in ethanol as a solvent, and then introduce ammonia gas to make the pH of the material greater than 10.

[0036] Step 3: Add diatomaceous earth-loaded elemental Ni to the ethanol solution containing dicyandiamide, which has been adjusted to pH, and then introduce ammonia gas to displace the air in the reactor.

[0037] Step 4: Start the stirring device and introduce H2 into the air-purified reactor until the pressure on the reactor gauge reaches 3.0 MPa;

[0038] Step 5: Turn on the heating control device to heat the material in the reactor, and react for 12 hours under the condition of continuous H2 introduction and controlling the material temperature at 70-80℃ to obtain hydrogenated material;

[0039] Step 6: Cool the hydrogenated material obtained in Step 5 until the material temperature is below 40°C, and then filter or centrifuge it under N2 protection to obtain the hydrogenated material with the catalyst removed.

[0040] Step 7: The hydrogenated material after the catalyst has been removed is subjected to atmospheric distillation to recover the ethanol and obtain concentrated hydrogenated material.

[0041] Step 8: The concentrated hydrogenated material obtained in Step 7 is subjected to vacuum distillation, and the distillate at 100-102℃ / 2mmHg is collected to obtain a dipropylenetriamine product with a mass percentage of 98.7%.

[0042] Example 2

[0043] A method for preparing diallyltriamine from high-boiling oil obtained by catalytic hydrogenation of aminopropionitrile distillation using the VB1 process includes the following steps:

[0044] Step 1: A siloxy-supported acid catalyst with molecular sieve as support and phosphosilicate as active component is added to the high-boiling oil of aminopropionitrile distillation. In-situ catalytic cracking and vacuum distillation are carried out under continuous stirring, and the distillation liquid fraction at 156-157℃ / 10mmHg is collected to obtain a dicyandiethylamine distillate with a mass percentage of 98.5% at a yield of 80.2% relative to the mass of the high-boiling oil of aminopropionitrile distillation.

[0045] Step 2: Dissolve the dicyandiethylamine distillate in toluene as a solvent, and then introduce NH3 to make the pH of the material greater than 10;

[0046] Step 3: Add Raney Ni to the toluene solution containing dicyandiethylamine that has been pH adjusted, and then purge with ammonia to displace the air in the reactor.

[0047] Step 4: Start the stirring device and introduce H2 into the air-purified reactor until the pressure on the reactor gauge reaches 3.50 MPa;

[0048] Step 5: Turn on the heating control device to heat the material in the reactor, and react for 12 hours under the condition of continuous H2 introduction and controlling the material temperature at 70-80℃ to obtain hydrogenated material;

[0049] Step 6: Cool the hydrogenated material obtained in Step 5 until the material temperature is below 40°C, and then filter or centrifuge it under N2 protection to obtain the hydrogenated material with the catalyst removed.

[0050] Step 7: The hydrogenated material after the catalyst has been removed is subjected to atmospheric distillation to recover the toluene and obtain the concentrated hydrogenated material.

[0051] Step 8: The concentrated hydrogenated material obtained in Step 7 is subjected to vacuum distillation, and the distillate at 107-109℃ / 9mmHg is collected to obtain a dipropylenetriamine product with a mass percentage of 98.4%.

[0052] Example 3

[0053] A method for preparing diallyltriamine from high-boiling oil obtained by catalytic hydrogenation of aminopropionitrile distillation using the VB1 process includes the following steps:

[0054] Step 1: A siloxy-based supported acid catalyst, consisting of a mixture of silica gel and molecular sieve in a mass ratio of 1.0:1.0 as a carrier and phosphoric acid / silicic acid / phosphosilicic acid as the active components, is added to the high-boiling oil of aminopropionitrile distillation. In-situ catalytic cracking and vacuum distillation are carried out under continuous stirring, and the distillation liquid fraction at 134-136℃ / 1mmHg is collected to obtain a dicyandiethylamine distillate with a mass percentage of 98.2% at a yield of 82.3% relative to the mass of the high-boiling oil of aminopropionitrile distillation.

[0055] Step 2: Dissolve the dicyandiethylamine distillate in methanol as a solvent, and then introduce NH3 to make the pH of the material greater than 10.

[0056] Step 3: Add Raney Ni to the methanol solution containing dicyandiethylamine whose pH has been adjusted, and then purge NH3 to displace the air in the reactor.

[0057] Step 4: Start the stirring device and introduce H2 into the air-purified reactor until the pressure on the reactor gauge reaches 3.6 MPa;

[0058] Step 5: Turn on the heating control device to heat the material in the reactor, and react for 10 hours under the condition of continuous H2 introduction and controlling the material temperature at 75-85℃ to obtain hydrogenated material;

[0059] Step 6: Cool the hydrogenated material obtained in Step 5 until the material temperature is below 40°C, and then filter or centrifuge it under N2 protection to obtain the hydrogenated material with the catalyst removed.

[0060] Step 7: The hydrogenated material after the catalyst has been removed is subjected to atmospheric distillation to recover the methanol and obtain concentrated hydrogenated material.

[0061] Step 8: The concentrated hydrogenated material obtained in Step 7 is subjected to vacuum distillation, and the distillate at 114-116℃ / 14mmHg is collected to obtain a dipropylenetriamine product with a mass percentage of 98.8%.

Claims

1. A process for the preparation of dipropargyltriamine by catalytic hydrogenation of high-boiling oil from rectification of aminopropionitrile from the VB1 process, characterized in that: First, the aminoacrylonitrile rectification high-boiling oil produced in the aminoacrylonitrile preparation section when acrylonitrile is used as raw material to produce VB1 is subjected to rectification or in-situ catalytic cracking reaction rectification to remove the polymers or convert part of the polymers into small molecular compounds, and a dicyanoethylamine distillate with a mass percentage of dicyanoethylamine greater than 97% is obtained at a yield of more than 75% relative to the mass of the aminoacrylonitrile rectification high-boiling oil; second, the dicyanoethylamine distillate is dissolved in an organic solvent, and then subjected to catalytic hydrogenation under alkaline conditions and in the presence of a catalyst to obtain a hydrogenated material containing dipropylene triamine; third, the catalyst in the hydrogenated material containing dipropylene triamine obtained is recovered by filtration or centrifugation, and then distilled to recover the organic solvent therein; and finally, the hydrogenated material containing dipropylene triamine from which the organic solvent has been recovered is subjected to vacuum rectification to obtain a dipropylene triamine product with a mass percentage greater than 97%.

2. The process for preparing dipropargyltriamine from high-boiling oil by catalytic hydrogenation of aminopropionitrile rectified by the VB1 process according to claim 1, characterized in that: The rectification or in-situ catalytic cracking reaction rectification of the aminoacrylonitrile rectification high-boiling oil is carried out under reduced pressure, and the collection of rectification fractions is performed according to the relationship between the boiling point t(℃) of the material and the corresponding external pressure P(mmHg) t=94.76+107.26 / (2.731-lgP), so that a dicyanoethylamine distillate with a mass percentage of dicyanoethylamine greater than 97% is obtained at a yield of more than 75% relative to the mass of the aminoacrylonitrile rectification high-boiling oil.

3. The rectification of p-aminopropionitrile with high-boiling oils in a catalytic cracking reaction in situ according to claim 2, characterized in that: The catalyst used for the in-situ catalytic cracking reaction rectification of the aminoacrylonitrile rectification high-boiling oil is a siloxyl solid acid catalyst with a mixture of one or more of zeolite, silica gel and molecular sieve in a certain proportion as the carrier, and phosphoric acid / silicic acid / phosphotungstic acid / silicotungstic acid and / or phosphosilicic acid as the active component.

4. The process for preparing dipropargyltriamine by catalytic hydrogenation of high-boiling oil from rectification of aminopropionitrile by VB1 process according to claim 1, characterized by that: The organic solvent used for dissolving the dicyanoethylamine distillate obtained by vacuum rectification or in-situ catalytic cracking vacuum reaction rectification of the aminoacrylonitrile rectification high-boiling oil is a mixture of one or more of methanol, ethanol, dioxane, benzene, toluene and petroleum ether in a certain proportion.

5. The process of claim 1, wherein the high-boiling oil is catalytically hydrogenated to prepare dipropargyltriamine from the distillation of aminopropionitrile by the VB1 process. The substance used to provide alkaline conditions for the catalytic hydrogenation of the dicyanoethylamine distillate obtained by vacuum rectification or in-situ catalytic cracking vacuum reaction rectification of the aminoacrylonitrile rectification high-boiling oil is a mixture of one or more of NH3, NaOH, KOH, Ca(OH)2, Na2CO3 and K2CO3 in a certain proportion.

6. The process of claim 1, wherein the high-boiling oil is catalytically hydrogenated to prepare dipropargyltriamine from the distillation of aminopropionitrile by the VB1 process. The catalyst used for the catalytic hydrogenation of the dicyanoethylamine distillate obtained by vacuum rectification or in-situ catalytic cracking vacuum reaction rectification of the aminoacrylonitrile rectification high-boiling oil is a mixture of one or more of diatomite-supported elemental Ni, alumina-supported elemental Ni, Raney Ni, PtO2 and Pd / C in a certain proportion.

7. The process of claim 1, wherein the high-boiling oil is catalytically hydrogenated to prepare dipropargyltriamine from the distillation of aminopropionitrile by the VB1 process. The hydrogenated material containing dipropylene triamine from which the organic solvent has been recovered is subjected to vacuum rectification, and the collection of rectification fractions is performed according to the relationship between the boiling point t(℃) of the material and the corresponding external pressure P(mmHg) t=92.42+9.645 / (1.573-lgP), so that a dipropylene triamine product with a mass percentage greater than 97% is obtained.

8. The method according to claim 1 for preparing dipropylene triamine by catalytic hydrogenation of the aminoacrylonitrile rectification high-boiling oil from the VB1 process, comprising the following specific steps: The first step: under continuous stirring, the p-aminopropyl cyan is subjected to vacuum rectification or in-situ catalytic cracking vacuum reaction rectification, and the rectification liquid fraction under the corresponding external pressure is collected according to the relationship between the boiling point t (℃) of the material and the corresponding external pressure P (mmHg), i.e. t = 94.76 + 107.26 / (2.731-lgP), to obtain the dicyanoethylamine distillate from which the polymers are removed; The second step: the obtained dicyanoethylamine distillate is dissolved with a mixture of one or more solvents selected from the group consisting of methanol, ethanol, dioxane, benzene, toluene and petroleum ether in a certain proportion, and then one or more substances selected from the group consisting of NH3, NaOH, KOH, Ca(OH)2, Na2CO3, PtO2 and K2CO3 is added to make the pH of the material greater than 10; The third step: one or more substances selected from the group consisting of diatomite supported elemental Ni, alumina supported elemental Ni, Raney Ni, PtO2 and Pd / C is added to the basic organic mixture containing dicyanoethylamine whose pH has been adjusted, and then N2 or ammonia gas is introduced to replace the air in the reaction kettle; The fourth step: the stirring device is started and H2 is introduced into the reaction kettle to make the gauge pressure of the reaction kettle 0.1-8.0 MPa; The fifth step: the heating control device is started and the material in the reaction kettle is heated, and under the conditions of continuous introduction of H2 and control of the material temperature at 50-150℃, the reaction is carried out for 4-24 h, thereby obtaining the hydrogenated material; The sixth step: the hydrogenated material obtained in the fifth step is cooled to a temperature lower than 40℃, and then filtered or centrifuged under the protection of N2 to obtain the hydrogenated material from which the catalyst is removed; The seventh step: the hydrogenated material from which the catalyst is removed is subjected to atmospheric distillation to recover the solvent therein and obtain the concentrated hydrogenated material, and the recovered solvent can be used to partially replace the solvent in the second step for dissolving the dicyanoethylamine distillate; The eighth step: the concentrated hydrogenated material obtained in the seventh step is subjected to vacuum rectification, and the rectification fraction is collected according to the relationship between the boiling point t (℃) of the material and the corresponding external pressure P (mmHg), i.e. t = 92.42 + 9.645 / (1.573-lgP), thereby obtaining the product of dipropylene triamine with a mass percentage content of greater than 97%.

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