A method for preparing 1,5-pentanediisocyanate

Abstract

This invention relates to a method for preparing 1,5-pentanediisocyanate. The method includes: introducing 1,5-pentanediamine, phosgene, and a carrier gas into a Y-type spiral microchannel reactor for reaction; and then sequentially subjecting the reactants to gas-liquid separation and distillation to obtain 1,5-pentanediisocyanate. The molar ratio of 1,5-pentanediamine, phosgene, and carrier gas is 1:(2-4):(0-1). A baffle plate is provided in the mixing channel of the phosgene and carrier gas, including a first plate and a second plate disposed on both sides of the centerline of the mixing channel. A spiral flow disruptor is provided in the reaction channel of the Y-type spiral microchannel reactor. The preparation method provided by this invention achieves the preparation of 1,5-pentanediisocyanate in a solvent-free manner using a specific Y-type spiral microchannel reactor with specific proportions. The resulting 1,5-pentanediisocyanate has a high yield and advantages such as few byproducts, short processing time, and high efficiency.

Description

Technical Field

[0001] This invention relates to the field of synthesis, and more specifically to a method for preparing 1,5-pentanediisocyanate. Background Technology

[0002] 1,5-Pentanediisocyanate (PDI), also known as pentamethyl diisocyanate, has the molecular formula C7H. 10 N₂O₂, belonging to aliphatic diisocyanates, and its products and related derivatives possess excellent properties. Compared to HDI (hexamethylene diisocyanate), it has a higher carbon content and higher reactivity, and can replace HDI in its derivatives with superior performance. PDI has high reactivity, can cure at lower temperatures and in shorter times, improving energy efficiency, and can also enhance the chemical resistance, abrasion resistance, and gloss of materials. PDI is formulated into PDI biuret or trimers for the manufacture of polyurethane coatings, adhesives, inks, and artificial leather, etc. The resulting polyurethane coatings are characterized by resistance to yellowing and strong weather resistance.

[0003] The key raw material for producing bio-based PDI, bio-based 1,5-pentanediamine (PDA), can be prepared using bio-fermentation. Using lysine hydrochloride as a raw material, bio-based 1,5-pentanediamine is efficiently synthesized through whole-cell catalytic decarboxylation using microbial strains and lysine decarboxylase, completely solving the industrialization bottleneck of bio-based 1,5-pentanediamine.

[0004] Existing methods for preparing PDI mainly include direct phosgenation and salt formation photochemical reactions. The direct photochemical reaction involves reacting bio-based 1,5-pentanediamine directly with phosgene, followed by two steps of vacuum desolventizing and vacuum distillation to obtain the product 1,5-pentanediisocyanate.

[0005] For example, CN112500315A discloses a method for preparing low-hydrolyzable chlorine 1,5-pentanediisocyanate. The specific steps are as follows: First, phosgene is dissolved in a solvent at low temperature until saturation. While continuing to pass phosgene, a mixed solution of bio-based 1,5-pentanediamine and the solvent is added to the phosgene solution using a metering pump. After the addition is complete, the temperature is programmed and the reaction temperature and time are controlled to obtain a photochemical liquid containing 1,5-pentanediisocyanate. After the reaction is complete, the solvent is removed by vacuum distillation. Continued vacuum distillation yields a colorless liquid, i.e., 1,5-pentanediisocyanate. The beneficial effect of this invention is that it yields a low-hydrolyzable chlorine (less than 50 ppm) 1,5-pentanediisocyanate product that can be directly used in downstream applications. The operation process is simple and suitable for industrial production. However, in this invention, the mass ratio of total phosgene to bio-based 1,5-pentanediamine is 20:1-10:1, and the mass ratio of bio-based 1,5-pentanediamine to the total amount of solvent in the entire reaction process is 1:5-1:20. That is, this scheme uses a large amount of phosgene and solvent, resulting in low economic benefits.

[0006] The main problems with traditional PDI preparation methods are complex processes, numerous byproducts, large quantities of reactants, and high online phosgene requirements, posing serious safety hazards. Therefore, there is a need to develop a 1,5-pentanediisocyanate preparation process that offers high yield, simple process, material savings, and is more suitable for industrial production. Summary of the Invention

[0007] In view of the problems existing in the prior art, the purpose of the present invention is to provide a method for preparing 1,5-pentanediisocyanate, so as to solve the problems of low yield of 1,5-pentanediisocyanate, many by-products, need for solvents, and large amount of phosgene in the prior art.

[0008] To achieve this objective, the present invention adopts the following technical solution:

[0009] This invention provides a method for preparing 1,5-pentanediisocyanate, the method comprising the following steps:

[0010] 1,5-Pentanediamine, phosgene, and carrier gas were introduced into a Y-type spiral microchannel reactor for reaction. After the reaction, the material was successively subjected to gas-liquid separation and distillation to obtain 1,5-pentanediisocyanate.

[0011] The molar ratio of 1,5-pentanediamine, phosgene, and carrier gas is 1:(2-4):(0-1);

[0012] The mixing channel for phosgene and carrier gas is equipped with baffles, including a first plate and a second plate disposed on both sides of the center line of the mixing channel;

[0013] The Y-shaped spiral microchannel reactor is equipped with a spiral flow disruptor in its reaction channel.

[0014] The preparation method provided by this invention achieves the preparation of 1,5-pentanediamine into 1,5-pentanediisocyanate in a solvent-free manner under specific conditions by using a specific Y-type spiral microchannel reactor combined with a specific spiral baffle in the reaction channel. The resulting 1,5-pentanediisocyanate has a high yield and has the advantages of mild reaction conditions, few reaction byproducts, low free chlorine, short reaction time, and high efficiency.

[0015] In this invention, the molar ratio of 1,5-pentanediamine to phosgene is 1:(2-4), preferably 1:2.

[0016] In this invention, the Y-shaped helical microchannel reactor is constructed from materials that provide sufficient strength, volume stability, and suitable heat exchange characteristics for the invention. Suitable materials include stainless steel, carbon steel, copper, and alloys of any of the aforementioned metals, ceramics, glass, composite materials, or combinations thereof. The microchannel reactor can be fabricated using known techniques, including laser cutting, conventional machining, electrochemical machining, casting, water spraying, stamping, etching, and combinations thereof. The microchannel reactor can be constructed by removing portions to accommodate flow channels in multiple layers or sheets to control the flow of the reaction composition, carrier, and products. The microchannels can have cross-sectional shapes of any shape, such as rectangular, semi-circular, trapezoidal, etc., preferably circular.

[0017] In this invention, the thickness of the spiral baffle is 1-1.2 mm, the diameter is 6-7 mm, and the twist rate is 2.5-3. Using a spiral baffle within this parameter range can enhance the mixing efficiency of nitrogen, phosgene, and PDA within the channel, increase reaction efficiency, reduce reaction time, and decrease the amount of phosgene online, thus reducing the generation of byproducts. The diameter of the spiral baffle should be selected to match the diameter of the reaction channel of the Y-type spiral microchannel reactor to ensure that the spiral baffle can be placed within the reaction channel of the Y-type spiral microchannel reactor.

[0018] In this invention, the carrier gas is a medium that exists in gaseous form in the reactor at the reaction temperature and does not substantially react with the reactants or compounds that appear during the reaction, or is stable under the reaction conditions. Exemplary carrier gases include nitrogen, carbon dioxide, carbon monoxide, helium, or argon, with nitrogen being preferred.

[0019] As a preferred embodiment of the present invention, the 1,5-pentanediamine is a bio-based 1,5-pentanediamine.

[0020] In this invention, the preparation process of the bio-based 1,5-pentanediamine is as follows:

[0021] A lysine aqueous solution with a concentration of 200-220 g / L was heated to 30-40℃. Then, 0.2-0.3 kg of bacterial sludge (strain BL-DAB, the construction method of which is detailed in patent CN201410799948.8, implementation 1) was dissolved in 8-8.5 L of water and added together with 2-3 g of pyridoxal phosphate (PLP, lysine decarboxylase coenzyme with a final concentration of 0.1 mmol / L) to a conversion tank for whole-cell catalysis. The byproduct hydrochloric acid was gradually added dropwise to the solution, maintaining the pH of the solution at 6.3-6.7, and the catalysis time was 15-16 h to obtain a material with a pentamethylenediamine hydrochloride concentration of 250-260 g / L. After centrifugation, filtration, neutralization, distillation, and centrifugation, bio-based 1,5-pentanediamine with a purity of over 99% and a water content of less than 500 ppm was obtained. If 1,5-pentanediamine has low purity or high water content, impurities will be generated during the PDI preparation process, clogging the reaction channels and affecting the content of the PDI product.

[0022] As a preferred embodiment of the present invention, the volumetric flow rate of the 1,5-pentanediamine is 4-6 mL / min, for example, it can be 4 mL / min, 4.1 mL / min, 4.2 mL / min, 4.3 mL / min, 4.4 mL / min, 4.5 mL / min, 4.6 mL / min, 4.7 mL / min, 4.8 mL / min, 4.9 mL / min, 5 mL / min, 5.1 mL / min, 5.2 mL / min, 5.3 mL / min, 5.4 mL / min, 5.5 mL / min, 5.6 mL / min, 5.7 mL / min, 5.8 mL / min, 5.9 mL / min or 6 mL / min, but is not limited to the listed values, and other unlisted values ​​within this range are also applicable.

[0023] As a preferred embodiment of the present invention, the mass flow rate of the phosgene is 8-10 g / min, for example, it can be 8 g / min, 8.1 g / min, 8.2 g / min, 8.3 g / min, 8.4 g / min, 8.5 g / min, 8.6 g / min, 8.7 g / min, 8.8 g / min, 8.9 g / min, 9 g / min, 9.1 g / min, 9.2 g / min, 9.3 g / min, 9.4 g / min, 9.5 g / min, 9.6 g / min, 9.7 g / min, 9.8 g / min, 9.9 g / min or 10 g / min, but is not limited to the listed values, and other unlisted values ​​within this range are also applicable.

[0024] As a preferred technical solution of the present invention, the reaction channel diameter of the Y-type spiral microchannel reactor is 7-9 mm, for example, it can be 7 mm, 7.5 mm, 8 mm, 8.5 mm or 9 mm, but is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0025] As a preferred technical solution of the present invention, the residence time of the material in the Y-shaped spiral microchannel reactor is 40-80s, for example, it can be 40s, 41s, 42s, 43s, 44s, 45s, 46s, 47s, 48s, 49s, 50s, 51s, 52s, 53s, 54s, 55s, 56s, 57s, 58s, 59s, 60s, 61s, 62s, 63s, 64s, 65s, 66s, 67s, 68s, 69s, 70s, 71s, 72s, 73s, 74s, 75s, 76s, 77s, 78s, 79s, or 80s, but is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0026] As a preferred technical solution of the present invention, the reaction temperature in the Y-shaped spiral microchannel reactor is 100-150℃, for example, it can be 100℃, 102℃, 104℃, 106℃, 108℃, 110℃, 112℃, 114℃, 116℃, 118℃, 120℃, 122℃, 124℃, 126℃, 128℃, 130℃, 132℃, 134℃, 136℃, 138℃, 140℃, 142℃, 144℃, 146℃, 148℃ or 150℃, but is not limited to the listed values, and other unlisted values ​​within this range are also applicable.

[0027] As a preferred technical solution of the present invention, the reaction pressure in the Y-shaped spiral microchannel reactor is 0.3-0.6 MPa, for example, 0.3 MPa, 0.32 MPa, 0.34 MPa, 0.36 MPa, 0.38 MPa, 0.4 MPa, 0.42 MPa, 0.44 MPa, 0.46 MPa, 0.48 MPa, 0.5 MPa, 0.52 MPa, 0.54 MPa, 0.56 MPa, 0.58 MPa or 0.6 MPa, but is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0028] As a preferred technical solution of the present invention, the distillation method includes vacuum distillation.

[0029] As a preferred technical solution of the present invention, the preparation method includes the following: 1,5-pentanediamine, phosgene and carrier gas are introduced into a Y-type spiral microchannel reactor for reaction, and the reacted materials are sequentially subjected to gas-liquid separation and distillation to obtain 1,5-pentanediisocyanate;

[0030] The molar ratio of 1,5-pentanediamine, phosgene, and carrier gas is 1:(2-4):(0-1);

[0031] The mixing channel for phosgene and carrier gas is equipped with baffles, including a first plate and a second plate disposed on both sides of the center line of the mixing channel;

[0032] The reaction channel of the Y-type spiral microchannel reactor is equipped with a spiral-shaped flow disruptor.

[0033] Wherein, the 1,5-pentanediamine is bio-based 1,5-pentanediamine; the volumetric flow rate of the 1,5-pentanediamine is 4-6 mL / min; the mass flow rate of the phosgene is 8-10 g / min; the diameter of the reaction channel in the Y-type spiral microchannel reactor is 7-9 mm; the residence time of the material in the Y-type spiral microchannel reactor is 40-80 s; the reaction temperature in the Y-type spiral microchannel reactor is 100-150℃; the reaction pressure in the Y-type spiral microchannel reactor is 0.3-0.6 MPa; and the distillation method includes vacuum distillation.

[0034] Compared with existing technical solutions, the present invention has the following beneficial effects:

[0035] The preparation method provided by this invention adopts a solvent-free approach, using 1,5-pentanediamine and phosgene as raw materials, and employs a specific Y-type spiral microchannel reactor to achieve efficient preparation of 1,5-pentanediisocyanate. The resulting solution contains no 1,5-pentanediamine residue, and the product yield is ≥69.5%. Under further optimized conditions, a yield of over 90.1% can be obtained, and in the optimal solution, the yield can reach 95%. The product purity is ≥99.4%, and the free chlorine content is ≤0.06%. Attached Figure Description

[0036] Figure 1 This is a schematic diagram of the synthesis apparatus used in the embodiments of the present invention;

[0037] Figure 2 This is a schematic diagram of the Y-type spiral microchannel reactor used in the nitrogen pressurization embodiment of the present invention;

[0038] Figure 3 This is a schematic diagram of the baffle arrangement in the mixing channel in an embodiment of the present invention;

[0039] Figure 4 This is a schematic diagram of a conventional Y-type microchannel reactor in an embodiment of the present invention.

[0040] In the diagram: 1.1-mass flow meter, 1.2-volume flow pump, 2-Y-type spiral microchannel reactor, 2.1-mixing channel, 2.2-reaction channel, 3-gas-liquid separation equipment;

[0041] A-1,5-pentanediamine, B1-phosgene, B2-nitrogen, C-a mixture of hydrogen chloride and phosgene, D-1,5-pentanediisocyanate.

[0042] The present invention will now be described in further detail. However, the examples described below are merely simplified examples of the present invention and do not represent or limit the scope of protection of the present invention. The scope of protection of the present invention is determined by the claims. Detailed Implementation

[0043] To better illustrate the present invention and facilitate understanding of its technical solutions, typical but non-limiting embodiments of the present invention are as follows:

[0044] In the implementation of this invention, the following methods are employed: Figure 1 The equipment components shown are used for preparation. Specifically, 1,5-pentanediamine A is fed into port 1# of Y-type spiral microchannel reactor 2 through volumetric flow pump 1.2, phosgene B1 is fed into port 2# of Y-type spiral microchannel reactor 2 through mass flow meter 1.1, and nitrogen B2 is fed into port 3# of Y-type spiral microchannel reactor 2 through mass flow meter 1.1. After the mixture reaches the residence time in reaction channel 2.2 of Y-type spiral microchannel reactor 2, it enters gas-liquid separation device 3 to separate a mixed gas C of hydrogen chloride and phosgene. The liquid phase material is subjected to vacuum distillation to obtain 1,5-pentanediisocyanate D.

[0045] Phosgene B1 and nitrogen B2 are premixed in mixing channel 2.1, which is equipped with baffles. The mixture then enters reaction channel 2.2 for the reaction, which is equipped with a spiral flow deflector to ensure optimal reaction performance. Figure 2 As shown.

[0046] The mixing channel 2.1 for phosgene B1 and nitrogen B2 is equipped with baffles to enhance the mixing effect, consisting of a first baffle 2.1.1 and a second baffle 2.1.2 spaced at equal intervals, as shown below. Figure 3 As shown, the first plate 2.1.1 is located on one side of the center line of the mixing channel 2.1, and the second plate 2.1.2 is located on the other side of the center line. The first plate 2.1.1 is located on the opposite side of the middle position of two adjacent second plates 2.1.2.

[0047] For example, the first plate 2.1.1 and the second plate 2.1.2 are set at equal intervals, meaning that the distance between the first plate 2.1.1 and the second plate 2.1.2 is the same. Specifically, the vertical distance between the first plate 2.1.1 and the second plate 2.1.2 along the gas flow direction is 4-5 mm, and 4 mm is selected in this embodiment.

[0048] In this invention, 1,5-pentanediamine A and phosgene B1 can be introduced via a carrier gas such as nitrogen B2, or they can be introduced separately. The key is to ensure that the molar ratio of 1,5-pentanediamine A:phosgene B1:nitrogen B2 is controlled within the range specified in this invention. Specifically, when phosgene B1 is supplied to meet the reaction requirements, nitrogen B2 can be omitted as a carrier and for pressurization. At this time, the molar ratio of 1,5-pentanediamine A to phosgene B1 still meets the specified range. Specifically, the pressure of phosgene B1 reaching the laboratory in the material is constant. Nitrogen B2 is used to pressurize the phosgene B1 side, balancing the pressure between the PDA and the phosgene B1 side, while also increasing the pressure.

[0049] Furthermore, the pipeline through which 1,5-pentanediamine A is fed into the Y-type spiral microchannel reactor 2 via volumetric flow pump 1.2 is also equipped with a flow control valve and a corresponding venting pipeline.

[0050] Phosgene B1 is fed into the Y-type spiral microchannel reactor 2 through a mass flow meter 1.1. A control valve is also installed on the pipeline to control the flow rate and velocity of the gas.

[0051] Nitrogen gas B2 is fed into the Y-type spiral microchannel reactor 2 through a mass flow meter 1.1. A control valve is also installed on the pipeline to control the flow rate and velocity of the gas.

[0052] A pressure detection device is installed on the pipeline between the Y-type spiral microchannel reactor 2 and the gas-liquid separation device 3 to detect the pressure in the pipeline. A back pressure valve is also installed to control the pressure in the pipeline.

[0053] A volumetric flow meter, a pressure detection device, and a control valve are also installed on the pipeline between the gas-liquid separation device 3 and the vacuum distillation device to control the pressure and flow rate of the material entering the vacuum distillation device.

[0054] The product 1,5-pentanediamine was prepared by phosgenation of 1,5-pentanediisocyanate using the above-described preparation apparatus. The yield, purity, and free chlorine content of the product were determined and calculated using the following methods:

[0055] Product yield: (molar amount of 1,5-pentanediisocyanate obtained / molar amount of 1,5-pentanediamine added) × 100%;

[0056] Product purity: High-performance liquid chromatography (HPLC) was used for detection and analysis. The chromatographic column used in the test was an Agilent DB-530m × 0.25mm × 0.25μm; the vaporization chamber temperature was 160℃; the detector temperature was 250℃; the column temperature was 120℃ for 5 min, then increased to 250℃ at a rate of 20℃ / min, and held for 5 min; the carrier gas flow rate was 1 mL / min; the injection volume was 1 μm; and the split ratio was 50:1.

[0057] The testing procedure for free chlorine content is as follows:

[0058] (1) Weigh 9-11g (accurate to 0.01g) of sample (4g-6g is recommended when the hydrolyzed chlorine content is greater than 50mg / Kg) into a clean and dry 300mL conical flask, add 100mL of methanol, install a reflux condenser, stir and heat to boiling, and keep refluxed for 10min to ensure complete alcoholysis.

[0059] (2) Add 50 mL from the reflux condenser;

[0060] (3) Stir and heat under reflux for 30 minutes;

[0061] (4) Add 20 mL of acetone, cool to room temperature, transfer 10 mL of sodium chloride solution, and add 10 mL of nitric acid solution;

[0062] (5) Perform potentiometric titration using silver nitrate standard solution.

[0063] To ensure the accuracy of gold detection, blank tests are also conducted according to steps (1)-(5) above to eliminate the influence of solvents and additives such as acetone, sodium chloride, and nitric acid on the detection results.

[0064] The specific preparation process of 1,5-pentanediamine to 1,5-pentanediisocyanate using the above-described preparation apparatus is illustrated in detail in the following examples:

[0065] Example 1

[0066] Preparation of bio-based 1,5-pentanediamine:

[0067] 33 kg of lysine hydrochloride was added to a 250 L conversion tank, and water was added to bring the volume to 112 L (lysine concentration 220 g / L). The temperature was raised to 37 °C, and 0.24 kg of bacterial sludge (strain BL-DAB, the construction method of which is detailed in patent CN201410799948.8, implementation 1) was dissolved in 8 L of water. This solution, along with 2.82 g of pyridoxal phosphate (PLP, lysine decarboxylase coenzyme final concentration 0.1 mmol / L), was added to the conversion tank for whole-cell catalysis. The byproduct hydrochloric acid was gradually added dropwise to the solution, maintaining the pH at 6.3-6.7, and the catalysis time was 15 h, yielding pentanediamine hydrochloride with a concentration of 258 g / L. 10 L of the pentanediamine hydrochloride solution was added to 1.3 kg of sodium chloride for acid-base neutralization, followed by vacuum distillation, centrifugation, and secondary distillation to obtain bio-based pentanediamine with a purity of 99.5% and a water content of 165 ppm.

[0068] Example 2

[0069] The traditional direct phosgene method was used to prepare 1,5-pentanediisocyanate, as detailed below:

[0070] 60g of 1,5-pentanediamine obtained in Example 1 was directly mixed with 200mL of chlorobenzene and stirred for 0.5h until homogeneous. The mixture was then heated to 150°C and phosgene was introduced while stirring. Phosgene was continuously introduced at a flow rate of 15g / min for 1h, followed by stirring for 3h until the system became transparent and dark brown. The reflux temperature was controlled at -15°C. After photochemical reaction, the system temperature was maintained and N2 gas was introduced (4h). Finally, the product 1,5-pentanediisocyanate was obtained through two steps: desolvation under reduced pressure (1.5h) and distillation under reduced pressure (1h).

[0071] The total time for this process was 12 hours, with a product yield of 83.1%, a product purity of 99%, and a free chlorine content of 0.09%.

[0072] Example 3

[0073] The preparation of 1,5-pentanediisocyanate using a conventional Y-type microchannel reactor is illustrated in the schematic diagram of the microchannel reactor used. Figure 4 The specific preparation process is as follows:

[0074] The 1,5-pentanediamine obtained in Example 1 was pumped into the Y-type spiral microchannel reactor via a metering pump at a volumetric flow rate of 5 mL / min. Phosgene and carrier gas were metered by a mass flow meter and then fed into the mixing channel via the Y-type spiral microchannel reactor via the ports 2 and 3, respectively, at mass flow rates of 8.9 g / min and 0.6 g / min. The mixture then entered the reaction channel within the reactor. The material temperature in the microchannel reactor was 130°C, the pressure was 0.3 MPa, and the reaction residence time was 60 s. The reaction liquid entered a gas-liquid separator to separate phosgene and hydrogen chloride. The reaction liquid was colorless and transparent. PDA residue was found in the reaction liquid. After vacuum distillation, the product 1,5-pentanediamine isocyanate was obtained.

[0075] The process took a total of 4 hours, with a product yield of 28%, a product purity of 98.1%, and a free chlorine content of 0.12%.

[0076] Example 4

[0077] The preparation of 1,5-pentanediisocyanate using the Y-type spiral microchannel reactor of the present invention is as follows:

[0078] The 1,5-pentanediamine obtained in Example 1 was pumped into the Y-type spiral microchannel reactor via a metering pump at a flow rate controlled at 5 mL / min. Nitrogen gas was metered by a mass flow meter and flowed into the Y-type spiral microchannel reactor via a flow rate controlled at 0.6 g / min. Phosgene gas was metered by a mass flow meter and flowed into the Y-type spiral microchannel reactor via a flow rate controlled at 8.9 g / min. The material temperature in the microchannel reactor was 130°C, the pressure was 0.3 MPa, and the reaction residence time was 60 s. The reaction liquid entered a gas-liquid separator to separate phosgene and hydrogen chloride. The reaction liquid was colorless and transparent, and there was no PDA residue in the reaction liquid. The product 1,5-pentanediamine isocyanate was obtained by vacuum distillation.

[0079] The process took a total of 4 hours, with a product yield of 95%, a product purity of 99.4%, and a free chlorine content of 0.06%.

[0080] Example 5

[0081] The preparation of 1,5-pentanediisocyanate using the Y-type spiral microchannel reactor of the present invention is as follows:

[0082] The 1,5-pentanediamine obtained in Example 1 was pumped into the Y-type spiral microchannel reactor via a metering pump at a flow rate controlled at 5 mL / min. Nitrogen gas was metered by a mass flow meter and flowed into the Y-type spiral microchannel reactor via a flow rate controlled at 0.6 g / min. Phosgene gas was metered by a mass flow meter and flowed into the Y-type spiral microchannel reactor via a flow rate controlled at 8.9 g / min. The material temperature in the microchannel reactor was 100°C, the pressure was 0.3 MPa, and the reaction residence time was 60 s. The reaction liquid entered a gas-liquid separator to separate phosgene and hydrogen chloride. The reaction liquid was colorless and transparent, and there was no PDA residue in the reaction liquid. After vacuum distillation, the product 1,5-pentanediamine isocyanate was obtained.

[0083] The process took a total of 4 hours, with a product yield of 75.5%, a product purity of 97.9%, and a free chlorine content of 0.09%.

[0084] Example 6

[0085] The preparation of 1,5-pentanediisocyanate using the Y-type spiral microchannel reactor of the present invention is as follows:

[0086] The 1,5-pentanediamine obtained in Example 1 was pumped into the Y-type spiral microchannel reactor via a metering pump at a flow rate controlled at 5 mL / min. Nitrogen gas was metered by a mass flow meter and flowed into the Y-type spiral microchannel reactor via a flow rate controlled at 0.6 g / min. Phosgene gas was metered by a mass flow meter and flowed into the Y-type spiral microchannel reactor via a flow rate controlled at 8.9 g / min. The material temperature in the microchannel reactor was 150°C, the pressure was 0.3 MPa, and the reaction residence time was 60 s. The reaction liquid entered a gas-liquid separator to separate phosgene and hydrogen chloride. The reaction liquid was brown and transparent, and there was no PDA residue in the reaction liquid. The product 1,5-pentanediamine isocyanate was obtained by vacuum distillation.

[0087] The total time for this process was 4 hours, with a product yield of 90.1%, a product purity of 99.4%, and a free chlorine content of 0.1%.

[0088] Example 7

[0089] The preparation of 1,5-pentanediisocyanate using the Y-type spiral microchannel reactor of the present invention is as follows:

[0090] The 1,5-pentanediamine obtained in Example 1 was pumped into the Y-type spiral microchannel reactor via a metering pump at a flow rate controlled at 8 mL / min. Nitrogen gas was metered by a mass flow meter at a flow rate controlled at 1 g / min and introduced into the Y-type spiral microchannel reactor via a flow rate controlled at 2 g / min. Phosgene gas was metered by a mass flow meter at a flow rate controlled at 8.9 g / min and introduced into the Y-type spiral microchannel reactor via a flow rate controlled at 3 g / min. The material temperature in the microchannel reactor was 130°C, the pressure was 0.3 MPa, and the reaction residence time was 40 s. The reaction liquid entered a gas-liquid separator to separate phosgene and hydrogen chloride. The reaction liquid was colorless and transparent, and there was no PDA residue in the reaction liquid. The product 1,5-pentanediamine isocyanate was obtained by vacuum distillation.

[0091] The total time for this process was 3.3 hours, with a product yield of 69.5%, a product purity of 95.3%, and a free chlorine content of 0.19%.

[0092] Example 8

[0093] The preparation of 1,5-pentanediisocyanate using the Y-type spiral microchannel reactor of the present invention is as follows:

[0094] The 1,5-pentanediamine obtained in Example 1 was pumped into the Y-type spiral microchannel reactor via a metering pump at a flow rate controlled at 4 mL / min. Nitrogen gas was metered by a mass flow meter and flowed into the Y-type spiral microchannel reactor via a flow rate controlled at 0.5 g / min. Phosgene gas was metered by a mass flow meter and flowed into the Y-type spiral microchannel reactor via a flow rate controlled at 7.5 g / min. The material temperature in the microchannel reactor was 130°C, the pressure was 0.3 MPa, and the reaction residence time was 80 s. The reaction liquid entered a gas-liquid separator to separate phosgene and hydrogen chloride. The reaction liquid was brown and transparent, and there was no PDA residue in the reaction liquid. The product 1,5-pentanediamine isocyanate was obtained by vacuum distillation.

[0095] The total time for this process was 4.5 hours, with a product yield of 81.5%, a product purity of 99.3%, and a free chlorine content of 0.08%.

[0096] Example 9

[0097] The preparation of 1,5-pentanediisocyanate using the Y-type spiral microchannel reactor of the present invention is as follows:

[0098] The 1,5-pentanediamine obtained in Example 1 was pumped into the Y-type spiral microchannel reactor via a metering pump at a flow rate controlled at 5 mL / min. Nitrogen gas was metered by a mass flow meter at a flow rate controlled at 0.6 g / min and introduced into the Y-type spiral microchannel reactor via a flow rate controlled at 2 g / min. Phosgene gas was metered by a mass flow meter at a flow rate controlled at 8.9 g / min and introduced into the Y-type spiral microchannel reactor via a flow rate controlled at 3 g / min. The material temperature in the microchannel reactor was 130°C, the pressure was 0.5 MPa, and the reaction residence time was 60 s. The reaction liquid entered a gas-liquid separator to separate phosgene and hydrogen chloride. The reaction liquid was slightly yellow and transparent, and there was no PDA residue in the reaction liquid. The product 1,5-pentanediamine isocyanate was obtained by vacuum distillation.

[0099] The total time for this process was 3 hours, with a product yield of 87.5%, a product purity of 99.2%, and a free chlorine content of 0.1%.

[0100] Example 10

[0101] The preparation of 1,5-pentanediisocyanate using the Y-type spiral microchannel reactor of the present invention is as follows:

[0102] The 1,5-pentanediamine obtained in Example 1 was pumped into the Y-type spiral microchannel reactor via a metering pump at a flow rate controlled at 5 mL / min. Nitrogen gas was metered by a mass flow meter and flowed into the Y-type spiral microchannel reactor via a flow rate controlled at 0.6 g / min. Phosgene gas was metered by a mass flow meter and flowed into the Y-type spiral microchannel reactor via a flow rate controlled at 8.9 g / min. The material temperature in the microchannel reactor was 130°C, the pressure was 0.1 MPa, and the reaction residence time was 60 s. The reaction liquid entered a gas-liquid separator to separate phosgene and hydrogen chloride. The reaction liquid was slightly yellow and transparent, and there was no PDA residue in the reaction liquid. The product 1,5-pentanediamine isocyanate was obtained by vacuum distillation.

[0103] The total time for this process was 3 hours, with a product yield of 83.2%, a product purity of 99.5%, and a free chlorine content of 0.08%.

[0104] Example 11

[0105] 1,5-pentanediisocyanate was prepared using the Y-type spiral microchannel reactor of the present invention, without the introduction of a carrier gas during the preparation process, as detailed below:

[0106] The 1,5-pentanediamine obtained in Example 1 was pumped into the Y-type spiral microchannel reactor via a metering pump at a flow rate controlled at 5 mL / min. Nitrogen gas was metered by a mass flow meter at a flow rate controlled at 0 g / min and introduced into the Y-type spiral microchannel reactor via a flow rate controlled at 3 g / min. Phosgene gas was metered by a mass flow meter at a flow rate controlled at 8.9 g / min and introduced into the Y-type spiral microchannel reactor via a flow rate controlled at 2 g / min. The material temperature in the microchannel reactor was 130°C, the pressure was 0.3 MPa, and the reaction residence time was 60 s. The reaction liquid entered a gas-liquid separator to separate phosgene and hydrogen chloride. The reaction liquid was colorless and transparent, and there was no PDA residue in the reaction liquid. The product 1,5-pentanediamine isocyanate was obtained by vacuum distillation.

[0107] The process took a total of 4 hours, with a product yield of 87.4%, a product purity of 99.4%, and a free chlorine content of 0.06%.

[0108] The preparation parameters and product indicators of the above embodiments are summarized in Table 1.

[0109] Table 1

[0110]

[0111] The results of the above embodiments show that, compared with the traditional direct phosgenation method and the traditional Y-type microchannel method, the preparation method provided by the present invention, through a Y-type spiral microchannel reactor with a specific structure, under specific material ratios, and combined with specific reaction control parameters (such as reaction temperature, reactant flow rate, and reactant residence time), achieves the preparation of 1,5-pentanediisocyanate from 1,5-pentanediamine in a solvent-free manner. The yield of the obtained 1,5-pentanediisocyanate is high, and it has the advantages of mild reaction conditions, few by-products during the reaction, low free chlorine, short total reaction time, and high efficiency.

[0112] The present invention is described in detail through the above embodiments, but the present invention is not limited to the above detailed structural features, that is, it does not mean that the present invention must rely on the above detailed structural features to be implemented. Those skilled in the art should understand that any improvements to the present invention, equivalent substitutions for the components used in the present invention, additions of auxiliary components, and selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

[0113] The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solution of the present invention, and these simple modifications all fall within the protection scope of the present invention.

[0114] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present invention will not describe the various possible combinations separately.

[0115] Furthermore, various different embodiments of the present invention can be combined in any way, as long as they do not violate the spirit of the present invention, they should also be regarded as the content disclosed by the present invention.

Claims

1. A method for preparing 1,5-pentanediisocyanate, characterized in that, The preparation method includes the following: 1,5-Pentanediamine, phosgene, and carrier gas were introduced into a Y-type spiral microchannel reactor for reaction. After the reaction, the material was successively subjected to gas-liquid separation and distillation to obtain 1,5-pentanediisocyanate. The molar ratio of 1,5-pentanediamine, phosgene, and carrier gas is 1:(2-4):(0-1); the volumetric flow rate of 1,5-pentanediamine is 4-6 mL / min; and the mass flow rate of phosgene is 8-10 g / min. The mixing channel for phosgene and carrier gas is equipped with baffles, including a first plate and a second plate disposed on both sides of the center line of the mixing channel; The Y-type spiral microchannel reactor is equipped with a spiral baffle in its reaction channel. The spiral baffle has a thickness of 1-1.2 mm, a diameter of 6-7 mm, and a twist rate of 2.5-3. The reaction temperature inside the Y-shaped spiral microchannel reactor is 100-150℃.

2. The preparation method according to claim 1, characterized in that, The 1,5-pentanediamine is a bio-based 1,5-pentanediamine.

3. The preparation method according to claim 1, characterized in that, The reaction channel diameter of the Y-type spiral microchannel reactor is 7-9 mm.

4. The preparation method according to claim 1, characterized in that, The residence time of the material in the Y-shaped spiral microchannel reactor is 40-80 seconds.

5. The preparation method according to claim 1, characterized in that, The reaction pressure inside the Y-shaped spiral microchannel reactor is 0.3-0.6 MPa.

6. The preparation method according to claim 1, characterized in that, The distillation method includes vacuum distillation.

7. The preparation method according to claim 1, characterized in that, The preparation method includes the following: 1,5-Pentanediamine, phosgene, and carrier gas were introduced into a Y-type spiral microchannel reactor for reaction. After the reaction, the material was successively subjected to gas-liquid separation and distillation to obtain 1,5-pentanediisocyanate. The molar ratio of 1,5-pentanediamine, phosgene, and carrier gas is 1:(2-4):(0-1); The mixing channel for phosgene and carrier gas is provided with baffles, including a first plate and a second plate disposed on both sides of the center line of the mixing channel; The reaction channel of the Y-type spiral microchannel reactor is equipped with a spiral-shaped flow disruptor. Wherein, the 1,5-pentanediamine is bio-based 1,5-pentanediamine; the volumetric flow rate of the 1,5-pentanediamine is 4-6 mL / min; the mass flow rate of the phosgene is 8-10 g / min; the diameter of the reaction channel in the Y-type spiral microchannel reactor is 7-9 mm; the residence time of the material in the Y-type spiral microchannel reactor is 40-80 s; the reaction temperature in the Y-type spiral microchannel reactor is 100-150℃; the reaction pressure in the Y-type spiral microchannel reactor is 0.3-0.6 MPa; and the distillation method includes vacuum distillation.

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