Apparatus and method for the continuous carbonylation of ammonia to produce 1,5-pentanediaminecarbamate

Abstract

The application provides a device and a method for preparing 1,5-pentanediamine carbamate through a continuous carbonylation reaction. The device comprises a first micro-channel reactor, a second micro-channel reactor and a cooler in sequence. The method comprises the following steps: mixing 1,5-pentanediamine solution with dimethyl carbonate, and then performing a preliminary carbonylation reaction to obtain an intermediate product; mixing the intermediate product with dimethyl carbonate again, and then performing a deep carbonylation reaction to obtain a reaction product after cooling. The device divides the synthesis of 1,5-pentanediamine carbamate into two reaction stages through the arrangement of two-stage micro-channel reactors, so as to improve the conversion rate of raw materials and the selectivity of products. The method has high process safety, stable reaction process, high product purity, and does not need to use a catalyst in the preparation process, so that the production cost can be effectively reduced. The device has simple structure, simple operation, green environmental protection, and is suitable for large-scale application.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of organic synthesis and relates to a device and method for preparing 1,5-pentanediamine carbamate through continuous carbonylation. BACKGROUND

[0002] Aliphatic isocyanate, as a main raw material for preparing polyurethane, can endow polyurethane materials with excellent mechanical properties, outstanding chemical stability and excellent weather resistance due to its unique chemical structure, and can be widely applied in the fields of plastics, coatings, pesticides, dyes, adhesives, leather, rubber and fibers; pentanedinitrile (PDI) as an important aliphatic isocyanate has broad application prospects due to its characteristics of non-yellowing and strong weather resistance.

[0003] The existing PDI production basically adopts the process of phosgene, which has the disadvantages of complex process, generation of strong corrosive hydrochloric acid, etc., and uses highly toxic phosgene as raw material, which has serious safety hazards. Therefore, the process route of non-phosgene green synthesis of PDI has become the research focus in recent years, and the urethane pyrolysis method for synthesizing isocyanate is a reaction route with great application prospect, including the synthesis and pyrolysis of urethane; pentanediamine carbamate (PDC) as an important intermediate can be synthesized from pentanediamine through carbonylation.

[0004] CN 113603613A discloses a catalytic synthesis method of pentanediamine carbamate, which comprises: dissolving pentanediamine and a carbonylation agent in a solvent, adding a titanium dioxide catalyst for reaction to obtain pentanediamine carbamate; the focus of this method is the preparation process of the catalyst, and the stability of the catalyst is improved to improve the conversion rate and selectivity of the reaction, but this method does not involve the selection of the reaction device and the control of the reaction stage, and it is difficult to accurately control the reaction process.

[0005] CN 108689884A discloses a preparation method of 1,5-pentanedinitrile, which comprises: mixing 1,5-pentanediamine conversion liquid and extraction solvent to extract 1,5-pentanediamine, then dehydrating the extraction liquid to obtain a mixed liquid of 1,5-pentanediamine and extraction solvent; adding a catalyst, urea and extraction solvent to the mixed liquid to form a reaction system, and performing carbamate of 1,5-pentanediamine and reduced pressure distillation to obtain pentamethylene diamino butyl carbamate; mixing pentamethylene diamino butyl carbamate, a heat carrier and a catalyst to perform thermal cracking reaction, and separating to obtain extraction solvent and 1,5-pentanedinitrile. This method uses an extraction solvent to remove impurities, and also uses the extraction solvent as a raw material, but the structure of the reaction device is not involved, and the carbonization reaction stage is not divided.

[0006] In summary, for the preparation of 1,5-pentanediamine carbamate, it is also necessary to select a suitable device combination according to the characteristics of the reaction raw materials and the changes in the reaction process, and combine the corresponding process to improve the conversion rate and product yield of the reaction, while ensuring the safety and stability of the reaction, green and environmentally friendly. SUMMARY

[0007] In view of the problems existing in the prior art, the purpose of the present application is to provide a device and method for preparing 1,5-pentanediamine carbamate by continuous carbonylation reaction. The device divides the synthesis of 1,5-pentanediamine carbamate into two reaction stages by the arrangement of two-stage micro-channel reactors, thereby improving the conversion rate of raw materials and the selectivity of products, ensuring the safety and stability of the reaction process, and effectively reducing the cost without using catalysts.

[0008] To achieve this purpose, the present application adopts the following technical solutions:

[0009] On the one hand, the present application provides a device for preparing 1,5-pentanediamine carbamate by continuous carbonylation reaction, characterized in that the device comprises a first micro-channel reactor, a second micro-channel reactor and a cooler in sequence, and the micro-channel reactor is provided with a micron-scale channel inside, and the micron-scale channel has a diameter of 1-1000 μm, such as 1 μm, 10 μm, 50 μm, 100 μm, 200 μm, 500 μm, 800 μm or 1000 μm, but is not limited to the listed values, and other values not listed in this range are also applicable.

[0010] In the present application, for the preparation of 1,5-pentanediamine carbamate, two-stage micro-channel reactors are used to divide the carbonylation reaction of 1,5-pentanediamine into two reaction stages of preliminary carbonylation and deep carbonylation, so as to adjust the reaction environment of raw materials and improve the conversion rate of raw materials and the yield of products; the device has a simple structure, easy operation and high safety, and is suitable for large-scale application.

[0011] The following is a preferred technical solution of the present application, but is not a limitation of the technical solutions provided by the present application. Through the following technical solutions, the technical purposes and beneficial effects of the present application can be better achieved and realized.

[0012] As a preferred technical solution of the present application, a raw material feeding pipe is connected in front of the first micro-channel reactor.

[0013] Preferably, the raw material feeding pipe comprises a 1,5-pentanediamine solution feeding pipe and a dimethyl carbonate feeding pipe arranged in parallel.

[0014] Preferably, a heater is arranged on the feeding pipe, and preferably one heater is arranged on each feeding pipe.

[0015] As a preferred technical scheme of the present application, an intermediate tank is further arranged between the first micro-channel reactor and the second micro-channel reactor.

[0016] Preferably, a heater is further arranged between the intermediate tank and the second micro-channel reactor.

[0017] Preferably, the inlet of the second micro-channel reactor is further connected with another dimethyl carbonate feeding pipe.

[0018] Preferably, a heater is arranged on the dimethyl carbonate feeding pipe.

[0019] In another aspect, the present application provides a method for preparing 1,5-pentanediamine carbamate by continuous carbonylation reaction, which comprises the following steps:

[0020] (1) mixing 1,5-pentanediamine solution with dimethyl carbonate and then performing preliminary carbonylation reaction to obtain an intermediate product;

[0021] (2) mixing the intermediate product obtained in step (1) with dimethyl carbonate again to perform deep carbonylation reaction, and then cooling to obtain a reaction product.

[0022] As a preferred technical scheme of the present application, the mass concentration of the 1,5-pentanediamine solution in step (1) is 10-80 wt%, for example, 10 wt%, 20 wt%, 30 wt%, 40 wt%, 50 wt%, 60 wt%, 70 wt% or 80 wt%, etc., but not limited to the listed values, and other values not listed in this range are also applicable, and preferably 20-40 wt%.

[0023] Preferably, the molar ratio of 1,5-pentanediamine to dimethyl carbonate in step (1) is 1:(2-20), for example, 1:2, 1:5, 1:10, 1:15 or 1:20, etc., but not limited to the listed values, and other values not listed in this range are also applicable, and preferably 1:(4-10).

[0024] As a preferred technical scheme of the present application, the 1,5-pentanediamine solution and dimethyl carbonate in step (1) are each preheated before mixing.

[0025] Preferably, the preheating temperature is 30-90℃, for example, 30℃, 40℃, 50℃, 60℃, 70℃, 80℃ or 90℃, etc., but not limited to the listed values, and other values not listed in this range are also applicable, and preferably 60-80℃.

[0026] As a preferred technical scheme of the present application, the preliminary carbonylation reaction in step (1) is performed in a first micro-channel reactor.

[0027] Preferably, the temperature of the preliminary carbonylation reaction in step (1) is 30-100°C, such as 30°C, 40°C, 50°C, 60°C, 70°C, 80°C, 90°C or 100°C, but not limited to the listed values, other values not listed in the range of values are also applicable, preferably 60-90°C.

[0028] Preferably, the time of the preliminary carbonylation reaction in step (1) is 5-60 min, such as 5 min, 10 min, 15 min, 20 min, 30 min, 40 min, 50 min or 60 min, but not limited to the listed values, other values not listed in the range of values are also applicable, preferably 10-20 min.

[0029] As a preferred technical solution of the present application, the intermediate product in step (2) is heated again, and the dimethyl carbonate is also preheated, and the temperature reaches 120-180°C, such as 120°C, 130°C, 140°C, 150°C, 160°C, 170°C or 180°C, but not limited to the listed values, other values not listed in the range of values are also applicable, preferably 150-160°C.

[0030] Preferably, the molar ratio of 1,5-pentanediamine to total dimethyl carbonate in the intermediate product in step (2) is 1:(3-80), such as 1:3, 1:6, 1:10, 1:20, 1:30, 1:50, 1:60 or 1:80, but not limited to the listed values, other values not listed in the range of values are also applicable, preferably 1:(3-20).

[0031] As a preferred technical solution of the present application, the deep carbonylation reaction in step (2) is carried out in a second microchannel reactor.

[0032] Preferably, the temperature of the deep carbonylation reaction in step (2) is 120-180°C, such as 120°C, 130°C, 140°C, 150°C, 160°C, 170°C or 180°C, but not limited to the listed values, other values not listed in the range of values are also applicable, preferably 150-160°C.

[0033] Preferably, the time of the deep carbonylation reaction in step (2) is 10-600 s, such as 10 s, 15 s, 20 s, 45 s, 60 s, 120 s, 200 s, 300 s, 450 s or 600 s, but not limited to the listed values, other values not listed in the range of values are also applicable, preferably 10-20 s.

[0034] In the present application, the two reaction stages of the carbonylation reaction are selected at different temperatures, and the temperature of the latter is higher than that of the former, which can effectively improve the conversion rate of the reaction, and the deep reaction stage is controlled for a short time to avoid reducing the selectivity due to serious side reactions.

[0035] Preferably, the cooling in step (2) is carried out in a cooler.

[0036] Preferably, the temperature after the cooling in step (2) is reduced to 20-40℃, such as 20℃, 25℃, 30℃, 35℃ or 40℃, etc., but not limited to the listed values, and other values not listed in this range are also applicable.

[0037] As a preferred technical solution of the present application, the method comprises the following steps:

[0038] (1) 1,5-pentanediamine solution is mixed with dimethyl carbonate and then subjected to a preliminary carbonylation reaction, the mass concentration of the 1,5-pentanediamine solution is 10-80wt%, the molar ratio of the 1,5-pentanediamine to dimethyl carbonate is 1:(2-20), the 1,5-pentanediamine solution and dimethyl carbonate are each preheated before mixing, the preheating temperature is 30-90℃, the preliminary carbonylation reaction is carried out in a first microchannel reactor, the reaction temperature is 30-100℃, and the reaction time is 5-60min, to obtain an intermediate product;

[0039] (2) The intermediate product obtained in step (1) is mixed with dimethyl carbonate again to perform a deep carbonylation reaction, the intermediate product is heated again, and the dimethyl carbonate is also preheated, and the temperature of each reaches 120-180℃, the molar ratio of the 1,5-pentanediamine in the intermediate product to the total dimethyl carbonate is 1:(3-80), the deep carbonylation reaction is carried out in a second microchannel reactor, the reaction temperature is 120-180℃, the reaction time is 10-600s, and the temperature after cooling is reduced to 20-40℃, to obtain a reaction product.

[0040] Compared with the prior art, the present application has the following beneficial effects:

[0041] (1) The device of the present application divides the synthesis of 1,5-pentanediaminocarbamate into two reaction stages by arranging two-stage microchannel reactors, so as to improve the conversion rate of the raw material and the selectivity of the product, the conversion rate of 1,5-pentanediamine reaches more than 99%, and the selectivity of 1,5-pentanediaminocarbamate reaches more than 97%;

[0042] (2) The method of the present application has high process safety, stable reaction process, high purity of the obtained product, and does not require the use of a catalyst in the preparation process, which can effectively reduce the production cost;

[0043] (3) The device has simple structure, easy operation, green environmental protection, and is suitable for large-scale application. BRIEF DESCRIPTION OF DRAWINGS

[0044] Figure 1 is a structural schematic diagram of a device for preparing 1,5-pentanediamine carbamate by continuous carbonylation reaction provided in Embodiment 1 of the present application;

[0045] In the formula, 1 represents a first micro-channel reactor, 2 represents a second micro-channel reactor, 3 represents a cooler, and 4 represents a heater. DETAILED DESCRIPTION

[0046] In order to better illustrate the present application and facilitate the understanding of the technical solutions of the present application, the present application is further described in detail below. However, the following embodiments are only simple examples of the present application, and do not represent or limit the protection scope of the present application. The protection scope of the present application is subject to the claims.

[0047] The specific embodiment part of the present application provides a device and a method for preparing 1,5-pentanediamine carbamate by continuous carbonylation reaction. The device sequentially comprises a first micro-channel reactor 1, a second micro-channel reactor 2 and a cooler 3. The micro-channel reactor is internally provided with a micron-scale channel. The diameter of the micron-scale channel is 1-1000 μm.

[0048] The method comprises the following steps:

[0049] (1) 1,5-pentanediamine solution is mixed with dimethyl carbonate and then subjected to a preliminary carbonylation reaction to obtain an intermediate product.

[0050] (2) The intermediate product obtained in step (1) is mixed with dimethyl carbonate again and subjected to a deep carbonylation reaction. After cooling, a reaction product is obtained.

[0051] The following are typical but non-limiting embodiments of the present application:

[0052] Embodiment 1:

[0053] This embodiment provides a device for preparing 1,5-pentanediamine carbamate by continuous carbonylation reaction. The structural schematic diagram of the device is shown in Figure 1 The device sequentially comprises a first micro-channel reactor 1, a second micro-channel reactor 2 and a cooler 3. The micro-channel reactor is internally provided with a micron-scale channel. The diameter of the micron-scale channel is 100 μm.

[0054] The first micro-channel reactor 1 is connected in front of a raw material feeding pipe.

[0055] The raw material feeding pipe comprises a 1,5-pentanediamine solution feeding pipe and a dimethyl carbonate feeding pipe which are arranged in parallel.

[0056] Each feed pipe is provided with a heater 4.

[0057] The first micro-channel reactor 1 and the second micro-channel reactor 2 are sequentially provided with an intermediate tank 5 and a heater 4.

[0058] The inlet of the second micro-channel reactor 2 is also connected with another dimethyl carbonate feed pipe, which is provided with a heater 4.

[0059] Example 2

[0060] The present example provides a method for preparing 1,5-pentanediamine carbamate by continuous carbonylation reaction, which refers to the device in Example 1 and comprises the following steps:

[0061] (1) mixing 1,5-pentanediamine solution with dimethyl carbonate and then performing preliminary carbonylation reaction, the mass concentration of the 1,5-pentanediamine solution is 30 wt%, the molar ratio of the 1,5-pentanediamine to dimethyl carbonate is 1:4, the 1,5-pentanediamine solution and dimethyl carbonate are each preheated before mixing, the preheating temperature is 80℃, the preliminary carbonylation reaction is performed in the first micro-channel reactor 1, the reaction temperature is 80℃, the reaction time is 20 min, and an intermediate product is obtained;

[0062] (2) mixing the intermediate product obtained in step (1) with dimethyl carbonate again and performing deep carbonylation reaction, the intermediate product is heated again, the dimethyl carbonate is also preheated, the temperature of each reaches 160℃, the molar ratio of the 1,5-pentanediamine to the total dimethyl carbonate in the intermediate product is 1:10, the deep carbonylation reaction is performed in the second micro-channel reactor 2, the reaction temperature is 160℃, the reaction time is 15 s, and the temperature is reduced to 30℃ after cooling, and a reaction product is obtained.

[0063] In the present example, the conversion rate of 1,5-pentanediamine reaches almost 100% and the selectivity of 1,5-pentanediamine carbamate reaches 97.5% after the above two-step carbonylation reaction.

[0064] Example 3

[0065] The present example provides a method for preparing 1,5-pentanediamine carbamate by continuous carbonylation reaction, which refers to the device in Example 1 and comprises the following steps:

[0066] (1) 1,5-pentanediamine solution with a mass concentration of 10 wt% was mixed with dimethyl carbonate, and a preliminary carbonylation reaction was carried out, the molar ratio of 1,5-pentanediamine to dimethyl carbonate was 1:10, the 1,5-pentanediamine solution and dimethyl carbonate were mixed after being preheated, the preheating temperature was 60°C, the preliminary carbonylation reaction was carried out in the first microchannel reactor 1, the reaction temperature was 60°C, and the reaction time was 40 min, to obtain an intermediate product;

[0067] (2) The intermediate product obtained in step (1) was mixed with dimethyl carbonate again to carry out a deep carbonylation reaction, the intermediate product was heated again, and the dimethyl carbonate was also preheated, the temperature reached 140°C, the molar ratio of 1,5-pentanediamine to total dimethyl carbonate in the intermediate product was 1:16, the deep carbonylation reaction was carried out in the second microchannel reactor 2, the reaction temperature was 140°C, the reaction time was 20 s, and the temperature decreased to 25°C after cooling, to obtain a reaction product.

[0068] In this embodiment, after the above two-step carbonylation reaction, the conversion rate of 1,5-pentanediamine reached 99.8%, and the selectivity of 1,5-pentanediaminomethyl carbonate reached 97.6%.

[0069] Example 4:

[0070] The embodiment provides a method for preparing 1,5-pentanediaminomethyl carbonate through a continuous carbonylation reaction, the method refers to the device in Example 1, and comprises the following steps:

[0071] (1) 1,5-pentanediamine solution with a mass concentration of 10 wt% was mixed with dimethyl carbonate, and a preliminary carbonylation reaction was carried out, the molar ratio of 1,5-pentanediamine to dimethyl carbonate was 1:10, the 1,5-pentanediamine solution and dimethyl carbonate were mixed after being preheated, the preheating temperature was 60°C, the preliminary carbonylation reaction was carried out in the first microchannel reactor 1, the reaction temperature was 60°C, and the reaction time was 40 min, to obtain an intermediate product;

[0072] (2) The intermediate product obtained in step (1) was mixed with dimethyl carbonate again to carry out a deep carbonylation reaction, the intermediate product was heated again, and the dimethyl carbonate was also preheated, the temperature reached 140°C, the molar ratio of 1,5-pentanediamine to total dimethyl carbonate in the intermediate product was 1:16, the deep carbonylation reaction was carried out in the second microchannel reactor 2, the reaction temperature was 140°C, the reaction time was 20 s, and the temperature decreased to 25°C after cooling, to obtain a reaction product.

[0073] In this embodiment, the conversion rate of 1,5-pentanediamine reaches 99.7% and the selectivity of 1,5-pentanediaminocarbamate reaches 97.4% through the above two-step carbonylation reaction.

[0074] Example 5:

[0075] This embodiment provides a method for preparing 1,5-pentanediaminocarbamate through continuous carbonylation reaction, which refers to the device in Example 1 and includes the following steps:

[0076] (1) After mixing 1,5-pentanediamine solution and dimethyl carbonate, preliminary carbonylation reaction is carried out, the mass concentration of the 1,5-pentanediamine solution is 40wt%, the molar ratio of 1,5-pentanediamine and dimethyl carbonate is 1:2, the 1,5-pentanediamine solution and dimethyl carbonate are mixed after being preheated respectively, the preheating temperature is 90°C, the preliminary carbonylation reaction is carried out in the first micro-channel reactor 1, the reaction temperature is 95°C, the reaction time is 10 min, and the intermediate product is obtained;

[0077] (2) The intermediate product obtained in step (1) is mixed with dimethyl carbonate again to carry out deep carbonylation reaction, the intermediate product is heated again, the dimethyl carbonate is also preheated, and the temperature reaches 180°C, the molar ratio of 1,5-pentanediamine and total dimethyl carbonate in the intermediate product is 1:8, the deep carbonylation reaction is carried out in the second micro-channel reactor 2, the reaction temperature is 180°C, the reaction time is 10 s, and the temperature is reduced to 20°C after cooling, and the reaction product is obtained.

[0078] In this embodiment, the conversion rate of 1,5-pentanediamine reaches 99.7% and the selectivity of 1,5-pentanediaminocarbamate reaches 97.4% through the above two-step carbonylation reaction.

[0079] Example 6:

[0080] This embodiment provides a method for preparing 1,5-pentanediaminocarbamate through continuous carbonylation reaction, which refers to the device in Example 1 and includes the following steps:

[0081] (1) After mixing 1,5-pentanediamine solution and dimethyl carbonate, preliminary carbonylation reaction is carried out, the mass concentration of the 1,5-pentanediamine solution is 40wt%, the molar ratio of 1,5-pentanediamine and dimethyl carbonate is 1:2, the 1,5-pentanediamine solution and dimethyl carbonate are mixed after being preheated respectively, the preheating temperature is 90°C, the preliminary carbonylation reaction is carried out in the first micro-channel reactor 1, the reaction temperature is 95°C, the reaction time is 10 min, and the intermediate product is obtained;

[0082] (2) The intermediate product obtained in step (1) is mixed with dimethyl carbonate again for deep carbonylation reaction, the intermediate product is heated again, the dimethyl carbonate is also preheated, and the temperature reaches 150°C, the molar ratio of 1,5-pentanediamine to total dimethyl carbonate in the intermediate product is 1:30, the deep carbonylation reaction is carried out in the second microchannel reactor 2, the reaction temperature is 150°C, the reaction time is 40s, and after cooling, the temperature is reduced to 40°C, to obtain a reaction product.

[0083] In this embodiment, after the above two-step carbonylation reaction, the conversion rate of 1,5-pentanediamine reaches 99.9%, and the selectivity of 1,5-pentanediamine carbamate reaches 97.2%.

[0084] Example 7:

[0085] This embodiment provides a method for preparing 1,5-pentanediamine carbamate by continuous carbonylation reaction, which refers to the method in Example 2, and the difference is only that the reaction time of step (2) is 100s.

[0086] In this embodiment, due to the longer deep carbonylation reaction time, the methylation side reaction is more serious, and the selectivity of the product is reduced, which is only about 90% at this time.

[0087] Comparative Example 1:

[0088] This comparative example provides a device and a method for preparing 1,5-pentanediamine carbamate by continuous carbonylation reaction, which refers to the device in Example 1, and the difference is only that the second microchannel reactor 2 is not included.

[0089] The method refers to the method in Example 2, and the difference is only that the operation of step (2) is not included.

[0090] In this comparative example, since the second microchannel reactor is not provided, the raw material can only be subjected to preliminary carbonylation reaction, and at this time, the conversion rate can only reach 94%, but many products are only single-end carbonylation, which are intermediates, and the selectivity of 1,5-pentanediamine carbamate is only about 50%.

[0091] From the above examples and comparative examples, it can be seen that the device provided by the present application divides the synthesis of 1,5-pentanediamine carbamate into two reaction stages through the setting of two-stage microchannel reactors, so as to improve the conversion rate of the raw material and the selectivity of the product, the conversion rate of 1,5-pentanediamine reaches more than 99%, and the selectivity of 1,5-pentanediamine carbamate reaches more than 97%; the method has high process safety, stable reaction process, high purity of the obtained product, and does not need to use a catalyst in the preparation process, which can effectively reduce the production cost; the device has simple structure, easy operation, green environmental protection, and is suitable for large-scale application.

[0092] The present application is illustrated by the above embodiments, but the present application is not limited to the above detailed devices and methods, i.e. it is not meant that the present application must rely on the above detailed devices and methods to be implemented. It should be understood by those skilled in the art that any improvement of the present application, equivalent replacement of the devices of the present application, addition of auxiliary devices, selection of specific modes, etc. fall within the protection scope and disclosure scope of the present application.

Claims

1. A process for the preparation of 1,5-pentanediaminocarbamate by continuous carbonylation, characterized in that, The method comprises the following steps: (1) mixing a 1,5-pentanediamine solution with dimethyl carbonate to perform a preliminary carbonylation reaction to obtain an intermediate product; the preliminary carbonylation reaction is performed in a first micro-channel reactor; (2) mixing the intermediate product obtained in step (1) with dimethyl carbonate again to perform a deep carbonylation reaction, and obtaining a reaction product after cooling; the deep carbonylation reaction is performed in a second micro-channel reactor. The method for preparing 1,5-pentanediamine carbamate by continuous carbonylation reaction is performed by using a device for preparing 1,5-pentanediamine carbamate by continuous carbonylation reaction; the device comprises a first micro-channel reactor, a second micro-channel reactor and a cooler in sequence, and a micro-channel with a diameter of 1-1000 μm is arranged in the micro-channel reactor.

2. The method of claim 1, wherein, A raw material feeding pipe is connected to the front of the first micro-channel reactor.

3. The method of claim 2, wherein, The raw material feeding pipe comprises a 1,5-pentanediamine solution feeding pipe and a dimethyl carbonate feeding pipe arranged in parallel.

4. The method of claim 3, wherein, A heater is arranged on the feeding pipe.

5. The method of claim 4, wherein, A heater is arranged on each of the feeding pipes.

6. The method of claim 1, wherein, An intermediate tank is further arranged between the first micro-channel reactor and the second micro-channel reactor.

7. The method of claim 6, wherein, A heater is further arranged between the intermediate tank and the second micro-channel reactor.

8. The method of claim 1, wherein, Another dimethyl carbonate feeding pipe is further connected to the inlet of the second micro-channel reactor.

9. The method of claim 8, wherein, A heater is arranged on the dimethyl carbonate feeding pipe.

10. The method of claim 1, wherein, The mass concentration of the 1,5-pentanediamine solution in step (1) is 10-80 wt%.

11. The method of claim 10, wherein, The mass concentration of the 1,5-pentanediamine solution in step (1) is 20-40 wt%.

12. The method of claim 1, wherein, The molar ratio of the 1,5-pentanediamine to dimethyl carbonate in step (1) is 1:(2-20).

13. The method of claim 12, wherein, The molar ratio of the 1,5-pentanediamine to dimethyl carbonate in step (1) is 1:(4-10).

14. The method of claim 1, wherein, The 1,5-pentanediamine solution and dimethyl carbonate in step (1) are mixed after being preheated respectively.

15. The method of claim 14, wherein, The preheating temperature is 30-90 °C.

16. The method of claim 15, wherein, The preheating temperature is 60-80 °C.

17. The method of claim 1, wherein, The temperature of the preliminary carbonylation reaction in step (1) is 30-100 °C.

18. The method of claim 17, wherein, The temperature of the preliminary carbonylation reaction in step (1) is 60-90 °C.

19. The method of claim 1, wherein, The time of the preliminary carbonylation reaction in step (1) is 5-60 min.

20. The method of claim 19, wherein, The time of the preliminary carbonylation reaction in step (1) is 10-20 min.

21. The method of claim 1, wherein, The intermediate product in step (2) is heated again, and the dimethyl carbonate is also preheated, and the temperature reaches 120-180 °C.

22. The method of claim 21, wherein, The intermediate product in step (2) is heated again, and the dimethyl carbonate is also preheated, and the temperature reaches 150-160 °C.

23. The method of claim 1, wherein, The molar ratio of the 1,5-pentanediamine to the total dimethyl carbonate in the intermediate product in step (2) is 1:(3-80).

24. The method of claim 23, wherein, The molar ratio of the 1,5-pentanediamine to the total dimethyl carbonate in the intermediate product in step (2) is 1:(3-20).

25. The method of claim 1, wherein, The temperature of the deep carbonylation reaction in step (2) is 120-180 °C.

26. The method of claim 25, wherein, The temperature of the deep carbonylation reaction in step (2) is 150-160 °C.

27. The method of claim 1, wherein, The time of the deep carbonylation reaction in step (2) is 10-600 s.

28. The method of claim 27, wherein, The time of the deep carbonylation reaction in step (2) is 10-20 s.

29. The method of claim 1, wherein, The cooling in step (2) is performed in a cooler.

30. The method of claim 1, wherein, The temperature after the cooling in step (2) is reduced to 20-40℃.

31. The method of claim 1, wherein, The method comprises the following steps: (1) a preliminary carbonylation reaction is performed after mixing a 1,5-pentanediamine solution with dimethyl carbonate, the mass concentration of the 1,5-pentanediamine solution is 10-80wt%, the molar ratio of the 1,5-pentanediamine to dimethyl carbonate is 1:(2-20), the 1,5-pentanediamine solution and dimethyl carbonate are each preheated before mixing, the preheating temperature is 30-90℃, the preliminary carbonylation reaction is performed in a first microchannel reactor, the reaction temperature is 30-100℃, the reaction time is 5-60min, and an intermediate product is obtained; (2) the intermediate product obtained in step (1) is mixed with dimethyl carbonate again to perform a deep carbonylation reaction, the intermediate product is heated again, the dimethyl carbonate is also preheated, and the temperature reaches 120-180℃, the molar ratio of the 1,5-pentanediamine to the total dimethyl carbonate in the intermediate product is 1:(3-80), the deep carbonylation reaction is performed in a second microchannel reactor, the reaction temperature is 120-180℃, the reaction time is 10-600s, the temperature after cooling is reduced to 20-40℃, and a reaction product is obtained.

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