A method for preparing methyl pentanediamine carbamate using furfurylamine as a raw material

Abstract

The present invention relates to a method for preparing methyl pentanediamine carbamate using furfurylamine as a raw material. This method uses furfurylamine, a downstream product of the biomass-based platform molecule furfural, as a raw material. Through the hydrodeamination amination of methyl 2-furfurylmethylcarbamate, N-(5-aminopentyl)carbamic acid methyl ester is prepared, and finally methyl pentanediamine carbamate is synthesized. The present invention provides a new process route for synthesizing methyl pentanediamine carbamate, solves the problem of serious pollution in the production process of PDI, meets the development requirements of green chemistry, and has broad industrial prospects.

Description

Technical Field

[0001] The present invention relates to a method for preparing methyl pentanediamine carbamate using furfurylamine as a raw material, belonging to the field of organic synthesis. Background Art

[0002] 1,5-Pentamethylene diisocyanate (PDI) is an aliphatic diisocyanate with a wide range of applications. Compared with aromatic isocyanates, the molecular structure of PDI does not contain a benzene ring, has a small steric hindrance, good yellowing resistance, heat resistance and light stability, and the prepared polyurethane foam materials can be used in high-tech fields such as airplanes and ships. At the same time, PDI has a saturated straight-chain symmetric molecular skeleton, and the products prepared therefrom have excellent performance and are often used in polymer material fields such as leather, coatings, adhesives, rigid and flexible foams, and elastic fibers.

[0003] The phosgene method is the main method for producing PDI at present. Chinese Patent CN103347852A discloses a method for preparing PDI. First, 1,5-pentanediamine is obtained by a biological method, and then 1,5-pentanediamine reacts directly with phosgene COCl2 to prepare PDI. There are a large number of by-products such as acyl chloride and hydrogen chloride in the products of this route, which will not only corrode equipment but also pollute the environment and do not meet the requirements of green development. In addition, there are problems in the biological synthesis of 1,5-pentanediamine such as low strength, poor tolerance, easy dissolution, low enzyme reuse efficiency, and high cost. Therefore, the non-phosgene clean production process of PDI has become a research hotspot. Among them, the carbamate pyrolysis method has received great attention due to its mild reaction conditions and recyclable by-products. As an intermediate, pentanediamine carbamate (PDC) is a key step in the production process of PDI.

[0004] From the perspective of the green development strategy, the efficient synthesis of bis-carbamate using biomass resources as raw materials is of great significance for the non-phosgene synthesis of diisocyanates. Summary of the Invention

[0005] The object of the present invention is to propose a method for preparing methyl pentanediamine carbamate using furfurylamine, a downstream product of biomass-based platform molecule furfural, as a raw material in view of the deficiencies in the current methods for producing methyl pentanediamine carbamate. This method uses furfurylamine, a downstream product of biomass-based platform molecule furfural, as a raw material, prepares N-(5-aminopentyl) carbamate by hydrogenolysis amination of methyl 2-furfurylmethylcarbamate, and finally synthesizes methyl pentanediamine carbamate. The present invention provides a new process route for synthesizing methyl pentanediamine carbamate, solves the problem of serious pollution in the production process of PDI, meets the development requirements of green chemistry, and has broad industrial prospects.

[0006] The technical solution of the present invention is as follows:

[0007] A method for preparing methyl pentanediamine carbamate using furfurylamine as a raw material, the method comprising the following steps:

[0008] (1) Step of preparing methyl 2-furfurylmethylcarbamate from furfurylamine and dimethyl carbonate:

[0009] Under a nitrogen atmosphere, furfurylamine, dimethyl carbonate and a catalyst are added to a reactor, stirred, and refluxed at 40-90 °C for 0.5-8 h, then cooled to room temperature to obtain the product methyl 2-furfurylmethylcarbamate;

[0010] The catalyst is sodium methoxide;

[0011] The molar ratio of furfurylamine to dimethyl carbonate is 1:8 to 1:100; the mass ratio of furfurylamine to the catalyst sodium methoxide is 1:0.12 to 1:0.8;

[0012] It further includes the following steps: after cooling to room temperature, deionized water is added to the reaction solution, the solid dissolves, the organic phase is separated through a separatory funnel, and the solvent is removed by vacuum distillation to obtain methyl 2-furfurylmethylcarbamate;

[0013] (2) Synthesizing methyl (5-aminopentyl)carbamate, which is one of the following two methods:

[0014] Method 1: Two-step synthesis:

[0015] First step, synthesizing methyl (5-hydroxypentyl)carbamate from methyl 2-furfurylmethylcarbamate:

[0016] Methyl 2-furfurylmethylcarbamate purified in the previous step, a first supported metal catalyst, and an organic solvent are added to a high-pressure reactor, and reacted at a H2 pressure of 0.1-8 MPa and a temperature of 20 °C - 170 °C for 0.5-10 h to obtain methyl (5-hydroxypentyl)carbamate;

[0017] Among them, for every 1 mmol of methyl 2-furfurylmethylcarbamate, 5-20 mL of organic solvent and 0.1-1 g of the first supported metal catalyst are added;

[0018] The first supported metal catalyst includes an active metal component and a support; among them: the active metal component includes active metal elements, and the active metal elements are Pd, Pt, Ru, Rh; preferably Pt, Ru; the support is selected from γ-Al2O3, ZrO2, TiO2, CeO2, SiO2, Nb2O5, HZSM-5 or activated carbon;

[0019] The loading amount of the active metal component is 1 wt% - 10 wt%;

[0020] Wherein: the mass of the active metal component is based on the mass of the active metal element contained in the active metal component; the mass of the carrier is based on the mass of the carrier itself;

[0021] The organic solvent is one or two of methanol, ethanol, tetrahydrofuran, 1,4-dioxane, toluene or isopropanol; preferably methanol;

[0022] The preferred hydrogen pressure is 1 to 4 MPa; the preferred reaction temperature is 100 to 170 °C; the preferred reaction time is 1 to 4 h;

[0023] Second step, amination of methyl (5-hydroxypentyl)carbamate to synthesize methyl N-(5-aminopentyl)carbamate:

[0024] After the reaction of synthesizing methyl (5-hydroxypentyl)carbamate from methyl 2-furfurylcarbamate in the first step is cooled to room temperature, the first supported metal catalyst is filtered out, the filtrate is transferred into a high-pressure reactor, and then the second supported metal catalyst and ammonia water are added, and the reaction is carried out at a pressure of 0.1 to 8 MPa H2 and a temperature of 120 to 200 °C for 2 to 12 h to obtain methyl N-(5-aminopentyl)carbamate;

[0025] Wherein, 0.1 to 1 g of metal catalyst is added per 1 mmol of methyl (5-hydroxypentyl)carbamate, and 0.5 - 10 mL of ammonia water is added per 20 mL of filtrate;

[0026] The active component of the second supported metal catalyst is one or two of Ru, Co or Ni, preferably the Ru and Co bimetal; the carrier is γ-Al2O3, MgO, HAP, TiO2, SiO2 or HZSM-5;

[0027] The loading amount of the active metal component is 1 wt% to 20 wt%;

[0028] The concentration of the ammonia water is 20 to 40 wt%;

[0029] The preferred hydrogen pressure is 1 to 4 MPa; the preferred reaction temperature is 150 to 180 °C;

[0030] Method two: one-step synthesis:

[0031] One-step hydrodeamination of methyl 2-furfurylcarbamate to synthesize methyl N-(5-aminopentyl)carbamate:

[0032] Methyl 2-furfurylcarbamate, the third supported metal catalyst, ammonia water and an organic solvent are added into a high-pressure reactor, and the reaction is carried out at a H2 pressure of 0.1 to 8 MPa and a temperature of 20 °C to 180 °C for 0.5 to 12 h to obtain methyl N-(5-aminopentyl)carbamate.

[0033] Among them, for every 1 mmol of methyl 2-furfurylcarbamate, 5-20 mL of an organic solvent and 0.1-1 g of a supported metal catalyst are added; for every 20 mL of the organic solvent, 0.5-10 mL of ammonia water is added.

[0034] The organic solvent is one or two of methanol, ethanol, tetrahydrofuran, 1,4-dioxane, toluene or isopropanol; preferably methanol.

[0035] The concentration of the ammonia water is 20-40 wt%.

[0036] The third supported metal catalyst includes an active metal component and a carrier; wherein the active metal element is one or two of Pd, Pt, Ru, Rh, Co or Ni, preferably a Pt-Co bimetal or a Ru-Co bimetal; the carrier is selected from γ-Al2O3, ZrO2, TiO2, CeO2, SiO2, Nb2O5, HZSM-5 or activated carbon.

[0037] The loading amount of the active metal component is 1-20 wt%.

[0038] The preferred hydrogen pressure is 1-6 MPa; the preferred reaction temperature is 120-170 °C; the preferred reaction time is 1-8 h.

[0039] (3) Synthesis of methyl pentanediamine carbamate from N-(5-aminopentyl)carbamic acid methyl ester and dimethyl carbonate:

[0040] After filtering the reaction solution obtained in the second step to remove the catalyst, the filtrate is rotary evaporated to remove the solvent, transferred into a reactor, sodium methoxide and dimethyl carbonate are added, and the temperature is raised to the reflux temperature under stirring conditions, and the reaction is stopped after reacting for 0.5-8 h at 40-90 °C.

[0041] The molar ratio of N-(5-aminopentyl)carbamic acid methyl ester to dimethyl carbonate is 1:8-1:100.

[0042] The mass ratio of N-(5-aminopentyl)carbamic acid methyl ester to the catalyst sodium methoxide is 1:0.12-1:0.8.

[0043] The substantial features of the present invention are:

[0044] This method includes three parts. First, methyl 2-furfurylcarbamate is prepared from furfurylamine. Second, N-(5-aminopentyl)carbamic acid methyl ester is prepared by hydroamination of methyl 2-furfurylcarbamate. Finally, the target product methyl pentanediamine carbamate is synthesized by the carbonate method.

[0045] Among them, in the preparation of methyl 2-furfurylmethylcarbamate in the first step, dimethyl carbonate is selected as the carbonylation agent, and methanol is the only by-product, and the reaction process is pollution-free; the hydroaminolysis of methyl 2-furfurylmethylcarbamate to prepare methyl N-(5-aminopentyl)carbamate has opened up a new process route and laid a foundation for the subsequent production of PDC and PDI.

[0046] The beneficial effects of the present invention are as follows:

[0047] (1) This method has realized for the first time the synthesis of methyl pentanediaminecarbamate from furfurylamine via methyl 2-furfurylmethylcarbamate and methyl N-(5-aminopentyl)carbamate.

[0048] (2) Methyl pentanediaminecarbamate (PDC) can be used as a precursor for the preparation of 1,5-pentamethylene diisocyanate (PDI) and has important application value in the high-end polyurethane manufacturing industry. As a downstream product of furfurylamine, a biomass-based platform molecule, furfurylamine has the characteristics of sustainability and low cost, opening up a new way for the synthesis of isocyanates and having the characteristics of greenness and inherent safety.

[0049] (3) In the two steps of synthesizing methyl pentanediaminecarbamate from furfurylamine via methyl 2-furfurylmethylcarbamate and methyl N-(5-aminopentyl)carbamate, dimethyl carbonate is used as the carbonylation agent, and methanol is the only by-product, and the conversion rates of both steps can reach 100%, and the product yield is 99%.

[0050] (4) The reaction of furfurylamine with dimethyl carbonate to prepare methyl 2-furfurylmethylcarbamate can effectively avoid the problem of cyclization of the intermediate product of furan ring hydrogenolysis at high temperature, and improve the selectivity of the hydrogenolysis product.

[0051] (5) The reaction conditions are mild, the process is easy to control, the supported metal catalyst is easy to separate, the safety is greatly improved, it meets the requirements of green chemistry, and has broad research prospects. Description of the Drawings

[0052] Figure 1 It is the GCMS spectrum of methyl 2-furfurylmethylcarbamate obtained in Example 1;

[0053] Figure 2 It is the GCMS spectrum of methyl (5-hydroxypentyl)carbamate obtained in Example 1;

[0054] Figure 3 It is the GCMS spectrum of methyl N-(5-aminopentyl)carbamate obtained in Example 1;

[0055] Figure 4 It is the GCMS spectrum of methyl pentanediaminecarbamate obtained in Example 1; Detailed Embodiments

[0056] The essential features and remarkable effects of the present invention can be embodied in the following embodiments, but they do not impose any limitations on the present invention. Those skilled in the art can make some non-essential improvements and adjustments based on the content of the present invention. The present invention will be further described below through specific embodiments.

[0057] The present invention provides a new method for preparing methyl pentanediamine carbamate using furfurylamine, a downstream product of the biomass platform compound furfural, as a raw material, opening up a new route for the preparation of isocyanates. The specific route is as follows:

[0058]

[0059] The first supported metal catalyst, the second supported metal catalyst, and the third supported metal catalyst involved in the present invention are all well-known materials;

[0060] For example, a 5wt% Pt / γ-Al2O3 catalyst is prepared as follows: 0.1403 g of H2PtCl6·6H2O (the percentage content of Pt is 37wt%) is dissolved in 2.5 mL of deionized water, and the resulting solution is slowly dropped into 1 g of γ-Al2O3. After stirring evenly, it is left standing overnight. Then, it is dried at 100 °C for 12 hours and calcined in a muffle furnace at 300 °C for 3 hours. Finally, it is reduced at 300 °C (volume flow rate N2:H2 = 60:40) for 3 h.

[0061] Supported metal catalysts with different carriers are prepared in the same way. However, it is not limited thereto.

[0062] Example 1

[0063] Step 1: 0.97 g (0.01 mol) of furfurylamine, 26 mL (0.3 mol) of dimethyl carbonate, and 0.16 g of sodium methoxide are successively added to a 100 mL three-necked flask, stirred, and refluxed and condensed. Under a nitrogen atmosphere, after reacting at 60 °C for 2 h, heating is stopped. After the reaction solution is cooled to room temperature, (at this time, the supernatant is directly analyzed by gas chromatography, and the reaction result is that the conversion rate of furfurylamine is 100%, and the yield of methyl 2-furfurylcarbamate is more than 99%). Deionized water is dropped into the three-necked flask, and the solid is completely dissolved, showing a layering phenomenon, that is, the upper layer is the aqueous phase and the lower layer is the organic phase. It is transferred to a separatory funnel. After the organic phase is separated from the bottom, the solvent dimethyl carbonate is finally removed by vacuum distillation to obtain high-purity methyl 2-furfurylcarbamate.

[0064] Step 2: 1 g (6.45 mmol) of methyl (2-furylmethyl)carbamate, 1.25 g of Pt / γ-Al₂O₃ with a loading of 5 wt%, and 50 mL of methanol were added to a 100 mL high-pressure reactor. The air in the reactor was replaced with nitrogen 5 times and then with hydrogen 5 times, and hydrogen was charged to 2 MPa. The reaction was carried out at 170 °C for 2 h. After the reaction ended, it was cooled to room temperature. The upper clear liquid was taken, filtered, and directly analyzed on a gas chromatograph. The conversion rate of methyl (2-furylmethyl)carbamate was 100%, the yield of methyl (5-hydroxypentyl)carbamate was 69%, the yield of methyl (tetrahydrofuran-2-ylmethyl)carbamate was 17%, and the yield of methyl (2-hydroxypentyl)carbamate was 14%.

[0065] Step 3: After filtering out the Pt / γ-Al₂O₃ catalyst in Step 2, the filtrate was transferred to a high-pressure autoclave (at this time, the solution contained 0.717 g (4.45 mmol) of methyl (5-hydroxypentyl)carbamate); then 50 mg of 5 wt% Ru-10 wt% Co / γ-Al₂O₃ and 4 mL of 28 wt% ammonia water were added. The reactor was sealed, the air in the reactor was replaced with nitrogen 5 times and then with hydrogen 5 times, and hydrogen was charged to 1 MPa. The reaction was carried out at 180 °C for 8 h. After the reaction ended, it was cooled to room temperature. The upper clear liquid was taken, filtered, and directly analyzed on a gas chromatograph. The conversion rate of methyl (5-hydroxypentyl)carbamate was 57%, and the yield of methyl N-(5-aminopentyl)carbamate was 39%.

[0066] Step 4: The Ru-Co / γ-Al₂O₃ in Step 3 was filtered, and after removing the solvent by vacuum distillation, 0.278 g (1.73 mmol) of methyl N-(5-aminopentyl)carbamate was obtained; 7 mL (0.083 mol) of dimethyl carbonate and 0.139 g of sodium methoxide were added, and it was transferred to a three-necked flask, stirred, and refluxed with condensation. Under a nitrogen atmosphere, the reaction was carried out at 60 °C for 2 h, then heating was stopped. After the reaction solution was cooled to room temperature, the supernatant was taken and directly analyzed on a gas chromatograph. The reaction result was that the conversion rate of methyl N-(5-aminopentyl)carbamate was 100%, and the yield of methyl pentanediaminecarbamate was 99%.

[0067] Example 2

[0068] Step 1 was the same as in Example 1. Other parts of Step 2 were the same as in Example 1, except that the reaction temperature was 100 °C. The reaction result was that the conversion rate of methyl (2-furylmethyl)carbamate was 100%, the yield of methyl (5-hydroxypentyl)carbamate was 39%, the yield of methyl (tetrahydrofuran-2-ylmethyl)carbamate was 50%, and the yield of methyl (2-hydroxypentyl)carbamate was 11%. Since under these conditions, the yield of methyl (5-hydroxypentyl)carbamate was not high, Steps 3 and 4 were not continued.

[0069] Example 3

[0070] Step 1 is the same as that in Example 1. Other parts of Step 2 are the same as those in Example 1, except that the catalyst is 5% Pt / ZrO₂. The reaction results are as follows: the conversion rate of methyl (2-furylmethyl)carbamate is 100%, the yield of methyl (5-hydroxypentyl)carbamate is 33%, the yield of methyl (tetrahydrofuran-2-ylmethyl)carbamate is 52%, and the yield of methyl (2-hydroxypentyl)carbamate is 15%. Since the yield of methyl (5-hydroxypentyl)carbamate is not high under these conditions, Steps 3 and 4 were not continued.

[0071] Example 4

[0072] Step 1 is the same as that in Example 1. Other parts of Step 2 are the same as those in Example 1, except that the H₂ pressure is 1 MPa. The reaction results are as follows: the conversion rate of methyl (2-furylmethyl)carbamate is 100%, the yield of methyl (5-hydroxypentyl)carbamate is 28%, the yield of methyl (tetrahydrofuran-2-ylmethyl)carbamate is 63%, and the yield of methyl (2-hydroxypentyl)carbamate is 9%. Since the yield of methyl (5-hydroxypentyl)carbamate is not high under these conditions, Steps 3 and 4 were not continued.

[0073] Example 5

[0074] Step 1 is the same as that in Example 1. Other parts of Step 2 are the same as those in Example 1, except that the solvent is tetrahydrofuran. The reaction results are as follows: the conversion rate of methyl (2-furylmethyl)carbamate is 95%, the yield of methyl (5-hydroxypentyl)carbamate is 18%, the yield of methyl (tetrahydrofuran-2-ylmethyl)carbamate is 72%, and the yield of methyl (2-hydroxypentyl)carbamate is 10%. Since the yield of methyl (5-hydroxypentyl)carbamate is not high under these conditions, Steps 3 and 4 were not continued.

[0075] Example 6

[0076] Steps 1 and 2 are the same as those in Example 1. Other parts of Step 3 are the same as those in Example 1, except that the reaction temperature is 150 °C. The reaction results are as follows: the conversion rate of methyl (5-hydroxypentyl)carbamate is 27%, and the yield of methyl (5-aminopentyl)carbamate is 16%. At this time, the amount of methyl N-(5-aminopentyl)carbamate is 0.114 g (0.712 mmol); since the yield of methyl N-(5-aminopentyl)carbamate is too low, Step 4 was not carried out.

[0077] Example 7

[0078] Steps 1 and 2 are the same as those in Example 1. Other parts of Step 3 are the same as those in Example 1, except that the catalyst is Co / γ-Al2O3. The reaction results show that the conversion rate of methyl (5-hydroxyamyl)carbamate is 52%, and the yield of methyl N-(5-aminopentyl)carbamate is 24%. At this time, the amount of methyl N-(5-aminopentyl)carbamate is 0.17 g (1.068 mmol). Step 4 is the same as that in Example 1. The conversion rate of methyl N-(5-aminopentyl)carbamate is 100%, and the yield of methyl pentanediaminecarbamate is 99%.

[0079] Example 8

[0080] Steps 1 and 2 are the same as those in Example 1. Other parts of Step 3 are the same as those in Example 1, except that the amount of ammonia water is 8 mL. The reaction results show that the conversion rate of methyl (5-hydroxyamyl)carbamate is 62%, and the yield of methyl N-(5-aminopentyl)carbamate is 9%. At this time, the amount of methyl N-(5-aminopentyl)carbamate is 0.064 g (0.4 mmol). Since the yield of methyl N-(5-aminopentyl)carbamate is too low, Step 4 is not carried out.

[0081] Example 9

[0082] In Step 1, 0.97 g (0.01 mol) of furfurylamine, 26 mL (0.3 mol) of dimethyl carbonate, and 0.16 g of sodium methoxide are successively added to a 50 mL three-necked flask, stirred, and refluxed and condensed. Under a nitrogen atmosphere, after reacting at 60 °C for 2 h, heating is stopped. After the reaction solution is cooled to room temperature, the supernatant is directly analyzed by gas chromatography. The reaction results show that the conversion rate of furfurylamine is 100%, and the yield of methyl 2-furfurylcarbamate is over 99%. Then, deionized water is added to the three-necked flask. The solids in the solvent are completely dissolved and a layering phenomenon appears. The upper layer is the aqueous phase, and the lower layer is the organic phase. Then, it is transferred to a separating funnel, and the organic phase is separated from the lower part. Finally, the solvent dimethyl carbonate is removed by vacuum distillation to obtain high-purity methyl 2-furfurylcarbamate.

[0083] In Step 2, 1 g (6.45 mmol) of methyl 2-furfurylcarbamate, 1.25 g of 5 wt% Pt-10 wt% Co / γ-Al2O3 catalyst, 50 mL of methanol, and 4 mL of 28 wt% ammonia water were added into a 100 mL high-pressure reactor. The air in the reactor was replaced with nitrogen 5 times and then with hydrogen 5 times, and hydrogen was charged to 2 MPa. The reaction was carried out at 170 °C for 4 h. After the reaction ended, it was cooled to room temperature. The supernatant was taken, filtered, and directly analyzed by gas chromatography. The conversion rate of methyl 2-furfurylcarbamate was 100%, the yield of methyl (5-hydroxypentyl)carbamate was 24%, the yield of methyl (tetrahydrofuran-2-ylmethyl)carbamate was 31%, the yield of methyl (2-hydroxypentyl)carbamate was 11%, and the yield of methyl N-(5-aminopentyl)carbamate was 32%.

[0084] In Step 3, the 5 wt% Pt-10 wt% Co / γ-Al2O3 catalyst in Step 2 was filtered. (At this time, 0.33 g (2.064 mmol) of methyl N-(5-aminopentyl)carbamate was obtained.) After the solvent was removed by vacuum distillation, 9 mL (0.104 mol) of dimethyl carbonate and 0.16 g of sodium methoxide were added, and the mixture was transferred into a three-necked flask, stirred, and refluxed and condensed. Under a nitrogen atmosphere, the heating was stopped after reacting at 60 °C for 2 h. After the reaction solution was cooled to room temperature, the supernatant was taken and directly analyzed by gas chromatography. The reaction result was that the conversion rate of methyl N-(5-aminopentyl)carbamate was 100%, and the yield of methyl pentanediaminecarbamate was 99%.

[0085] Matters not covered by this invention are well-known technologies.

Claims

1. A method for preparing methyl pentanediamine carbamate using furfurylamine as a raw material, characterized in that the method comprises the following steps: (1) The step of preparing methyl 2-furfurylmethylcarbamate from furfurylamine and dimethyl carbonate: Under a nitrogen atmosphere, furfurylamine, dimethyl carbonate and a catalyst are added to a reactor, stirred, and refluxed at 40-90 °C for 0.5-8 h, and then cooled to room temperature to obtain the product methyl 2-furfurylmethylcarbamate; The catalyst is sodium methoxide; The molar ratio of furfurylamine to dimethyl carbonate is 1:8-1:100; the mass ratio of furfurylamine to the catalyst sodium methoxide is 1:0.12-1:0.8; (2) Synthesizing methyl N-(5-aminopentyl)carbamate, which is one of the following two methods: Method 1: Two-step synthesis: The first step, synthesizing methyl (5-hydroxypentyl)carbamate from methyl 2-furfurylmethylcarbamate: Methyl 2-furfurylmethylcarbamate purified in the previous step, a first supported metal catalyst, and an organic solvent are added to a high-pressure reactor, and reacted at a H2 pressure of 1-4 MPa and 100 °C - 170 °C for 1-4 h to obtain methyl (5-hydroxypentyl)carbamate; Among them, for every 1 mmol of methyl 2-furfurylmethylcarbamate, 5-20 mL of organic solvent and 0.1-1 g of the first supported metal catalyst are added; The first supported metal catalyst includes an active metal component and a support; among them: the active metal component includes an active metal element, and the active metal element is Pt or Ru; the support is γ-Al2O3; The loading amount of the active metal component is 1 wt% - 10 wt%; The organic solvent is methanol; The second step, aminating methyl (5-hydroxypentyl)carbamate to synthesize methyl N-(5-aminopentyl)carbamate: After the reaction of synthesizing methyl (5-hydroxypentyl)carbamate from methyl 2-furfurylmethylcarbamate in the first step is cooled to room temperature, the first supported metal catalyst is filtered out, the filtrate is transferred into a high-pressure reactor, and then a second supported metal catalyst and ammonia water are added, and reacted at a H2 pressure of 1-4 MPa and 150-180 °C for 2-12 h to obtain methyl N-(5-aminopentyl)carbamate; Among them, for every 1 mmol of methyl (5-hydroxypentyl)carbamate, 0.1-1 g of metal catalyst is added, and for every 20 mL of filtrate, 0.5-4 mL of ammonia water is added; The active component of the second supported metal catalyst is a bimetal of Ru and Co, or Co; the support is γ-Al2O3; The loading amount of the active metal component is 1 wt% - 20 wt%; Method 2: One-step synthesis: One-step hydrodeamination of methyl 2-furfurylmethylcarbamate to synthesize methyl N-(5-aminopentyl)carbamate: Methyl 2-furfurylmethylcarbamate, a third supported metal catalyst, ammonia water and an organic solvent are added to a high-pressure reactor, and reacted at a H2 pressure of 1-6 MPa and 120-170 °C for 1-8 h to obtain methyl (5-aminopentyl)carbamate; Among them, for every 1 mmol of methyl 2-furfurylcarbamate, 5 - 20 mL of organic solvent and 0.1 - 1 g of supported metal catalyst are added; for every 20 mL of organic solvent, 0.5 - 10 mL of ammonia water is added. The organic solvent is one or two of methanol, ethanol, tetrahydrofuran, 1,4-dioxane, toluene or isopropanol. The third supported metal catalyst includes an active metal component and a support; wherein the active metal elements are Pt-Co bimetal or Ru-Co bimetal, and the support is γ-Al2O3. The loading amount of the active metal component is 1 - 20 wt%. (3) Synthesis of methyl pentanediaminecarbamate from N-(5-aminopentyl)carbamate and dimethyl carbonate: After filtering the reaction solution obtained in the second step to remove the catalyst, the filtrate is rotary evaporated to remove the solvent, transferred into a reactor, sodium methoxide and dimethyl carbonate are added, and the temperature is raised to the reflux temperature under stirring conditions, and the heating is stopped after reacting for 0.5 - 8 h at 40 - 90 °C. The molar ratio of N-(5-aminopentyl)carbamate to dimethyl carbonate is 1:8 - 1:

100. The mass ratio of N-(5-aminopentyl)carbamate to the catalyst sodium methoxide is 1:0.12 - 1:0.

8.

2. The method for preparing methyl pentanediamine carbamate using furfurylamine as a raw material according to claim 1, characterized in that In the step (1), the following steps are further included: after cooling to room temperature, deionized water is added to the reaction solution, the solid is dissolved, the organic phase is separated through a separating funnel, and the solvent is removed by vacuum distillation to obtain methyl 2-furfurylcarbamate.

3. The method for preparing methyl pentanediamine carbamate using furfurylamine as a raw material according to claim 1, characterized in that The concentration of the ammonia water in Method 1 or Method 2 in the step (2) is 20 - 40 wt%.

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