A method for preparing 2,5-bis(aminomethyl)furan from 5-chloromethylfurfural

Abstract

A method for preparing 2,5-di(aminomethyl)furan from 5-chloromethylfurfural involves reacting 5-chloromethylfurfural with phthalimide salt to prepare an intermediate product. The intermediate product is catalytically converted under a hydrogen or ammonia-hydrogen mixed atmosphere, followed by solid-liquid separation to obtain a 2,5-di(aminomethyl)furan solution and solid D. Solid D is washed with an alcoholic solution of hydrochloric acid to recover the catalyst and obtain a washing liquid. The washing liquid is then converted under an ammonia atmosphere, followed by the addition of sodium hydroxide or potassium hydroxide to continue the reaction, precipitating the phthalimide salt. The reactants are widely available and renewable; the reaction process is simple and efficient; the reaction conditions are mild; and the product separation and purification are simple, the catalyst preparation is simple, and it can be recycled and reused. The product, after separation and recrystallization purification, has a purity exceeding 99.9%, and the phthalimide salt can be recycled, showing promising application prospects.

Description

Technical Field

[0001] This invention relates to the field of 2,5-di(aminomethyl)furan preparation, and more particularly to a method for preparing 2,5-di(aminomethyl)furan from 5-chloromethylfurfural. Background Technology

[0002] Diamines are an important class of organic nitrogen compounds. Besides serving as key intermediates in the synthesis of pharmaceuticals, dyes, and agrochemicals, they are also widely used as monomers for the production of polyamides and polyureas. Currently, diamine production mainly relies on petroleum-based chemical feedstocks. However, with the development of sustainable chemistry, the development of renewable biomass-based amino compound synthesis technologies holds great promise. Among them, 2,5-disubstituted furan derivatives, 2,5-di(aminomethyl)furan, is considered one of the most promising bio-based diamine monomers, offering more possibilities for constructing novel bio-based polymers with unique functions.

[0003] Currently, the preparation of 2,5-di(aminomethyl)furan typically uses the biomass platform compound 5-hydroxymethylfurfural and its downstream derivatives such as 2,5-dicarboxyfuran, 2,5-dihydroxymethylfuran, 2,5-dicarboxyfuran dioxime, and 5-aminomethylfurfural alcohol as raw materials. In methods for preparing 2,5-di(aminomethyl)furan from 5-hydroxymethylfurfural, a stepwise reductive amination pathway using ammonia as the amine source is commonly employed. While the low reaction rate can be mitigated by using homogeneous noble metal catalysts, increasing the reaction temperature, or extending the reaction time, the reaction efficiency is difficult to improve due to the tendency of 5-hydroxymethylfurfural to polymerize during the reaction. Aldehydes readily generate corresponding amines through reductive amination. In the process of preparing 2,5-di(aminomethyl)furan from 2,5-dicarboxyfuran via aldehyde reductive amination, the generated primary amine intermediates readily polymerize with 2,5-dicarboxyfuran, resulting in a low yield of 2,5-di(aminomethyl)furan. Summary of the Invention

[0004] The purpose of this invention is to solve the aforementioned problems in the prior art and provide a method for producing 2,5-di(aminomethyl)furan with a highly active, recyclable, and easily separable catalyst, mild reaction conditions, and high yield. This invention catalytically converts 5-chloromethylfurfural to 2,5-di(aminomethyl)furan in two steps.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] This invention includes the following steps:

[0007] 1) The reaction substrate 5-chloromethylfurfural and phthalimide salt were added to the reaction solvent A, heated for a period of time and then cooled to room temperature. Excess water was added to the reaction solution to precipitate the solid. The solid was then filtered and dried below 60°C to obtain the intermediate product.

[0008] 2) The intermediate product obtained in step 1), the reaction reagent, the catalyst and the reaction solvent B are mixed and added to the reaction vessel. Hydrogen gas at a certain pressure is introduced and the reaction is sealed and heated for a certain time. Then it is cooled to room temperature to obtain 2,5-bis(aminomethyl)furan reaction solution, accompanied by the precipitation of solid precipitate.

[0009] 3) The 2,5-bis(aminomethyl)furan reaction solution obtained in step 2) was subjected to solid-liquid separation to obtain a 2,5-bis(aminomethyl)furan solution and solid D. The obtained 2,5-bis(aminomethyl)furan solution was distilled under reduced pressure to recover the reaction solvent B, yielding crude 2,5-bis(aminomethyl)furan product. Then, dichloromethane and water were added to the crude 2,5-bis(aminomethyl)furan product, mixed thoroughly, and allowed to stand for layering. The dichloromethane layer was separated, and the solvent was recovered. The aqueous phase was crystallized to obtain the high-purity solid product 2,5-bis(aminomethyl)furan.

[0010] 4) Wash the solid D obtained in step 3) with an alcoholic solution of hydrochloric acid to recover the catalyst and obtain a washing liquid. Inject the washing liquid and ammonia gas at a certain pressure into a reactor and react at a certain temperature for a certain time. After the reaction is completed, add at least one of sodium hydroxide or potassium hydroxide and keep the temperature to continue the reaction for a period of time to precipitate phthalimide salt, which can be used as the raw material in step 1).

[0011] In step 1), the mass concentration of the reaction substrate 5-chloromethylfurfural can be 0.001 to 1.0 g / mL.

[0012] In step 1), the reaction solvent A is at least one of dimethylformamide, acetonitrile, toluene, and ethyl acetate.

[0013] In step 1), the mass concentration of the phthalimide salt in the reaction solvent A is 0.001–1.5 g / mL. The phthalimide salt is sodium phthalimide or potassium phthalimide.

[0014] In step 1), the reaction temperature is 20–160°C and the reaction time is 0.25–48 h.

[0015] In step 2), the reaction solvent B is at least one of water, tetrahydrofuran, acetonitrile, diethyl ether, dichloromethane, toluene, ethyl acetate, N,N-dimethylformamide, methanol, or ethanol.

[0016] In step 2), the mass concentration of the intermediate product in the reaction solvent B is 0.001 to 1.0 g / mL.

[0017] In step 2), the reaction reagents include at least reaction reagent C, which is at least one of hydroxylamine aqueous solution, hydrazine hydrate, hydroxylamine hydrochloride, hydroxylamine sulfate, ammonia, ammonia water, and a methanol or ethanol solution of ammonia; the reaction reagents may also include reaction reagent B, which is one of sodium carbonate, potassium carbonate, calcium carbonate, sodium hydroxide, potassium hydroxide, calcium hydroxide, sodium ethoxide, sodium acetate, potassium acetate, potassium silicate, sodium silicate, hydrochloric acid, sulfuric acid, nitric acid, and acetic acid.

[0018] In step 2), the mass concentration of the reaction reagent B in the reaction solvent B is 0.00 to 1.0 g / mL.

[0019] In step 2), the molar concentration of the reaction reagent C in the reaction solvent B is 0.001 to 8.0 mol / L.

[0020] In step 2), the partial pressure of hydrogen gas as a reducing agent in the reaction vessel is 0.25 to 5.0 MPa.

[0021] In step 2), the reaction temperature is 30–200°C and the reaction time is 0.25–48 h.

[0022] In step 2), the catalyst is a Raney-type catalyst, such as Raney nickel, Raney cobalt, or Raney copper; or the catalyst is a supported catalyst composed of an active component and a support, wherein the active component is at least one of Ni, Cu, Co, Cr, Sn, Al, Bi, Ce, Pt, Pd, Au, Ag, Rh, Ru, Ir, Re, and Fe, and the support is a metal oxide of at least one of CaO, MgO, La2O3, Y2O3, SiO2, ZSM, HZSM, CeO2, ZrO2, Al2O3, TiO2, Nb2O5, SnO2, V2O5, MnO2, Fe2O3, Fe3O4, and MoO3.

[0023] The catalyst can be prepared by the commonly used impregnation method. The active component and the support are mixed in an aqueous solution, the mixture is stirred at room temperature for a certain time, and then subjected to rotary evaporation and drying. The solution is then subjected to oxidation in a muffle furnace at 200-600℃ and calcination and reduction in a tube furnace at 400-800℃ in a hydrogen atmosphere to obtain a supported catalyst. The catalyst is then ground into powder and stored in an inert atmosphere for use.

[0024] In step 2), the content of the active component, calculated as metal, is 0.1% to 100.0% of the mass of catalyst B; the amount of catalyst B added is 1.0% to 200.0% of the mass of 5-chloromethylfurfural.

[0025] In step 4), the partial pressure of the ammonia gas in the reaction vessel is 0.2 to 0.9 MPa.

[0026] In step 4), the reaction temperature is 60–200°C and the reaction time is 2–48 h.

[0027] In step 4), the amount of sodium hydroxide or potassium hydroxide used is 0.001 to 1.0 g / mL.

[0028] In step 4), the heat preservation and reaction continue for 0.25 to 10 hours.

[0029] Compared with the prior art, the beneficial effects achieved by the technical solution of this invention are:

[0030] This invention provides a two-step catalytic method for preparing 2,5-di(aminomethyl)furan from 5-chloromethylfurfural. In the first step, 5-chloromethylfurfural is mixed with a phthalimide salt in reaction solvent A, and an intermediate is prepared using the Gabriel reaction. In the second step, 2,5-di(aminomethyl)furan is catalytically converted from the intermediate obtained in the first step to a 2,5-di(aminomethyl)furan using a Raney-type catalyst, such as Raney nickel, Raney cobalt, Raney copper, or a supported metal oxide catalyst, in reaction solvent B under a hydrogen or a mixed hydrogen-ammonia atmosphere.

[0031] The obtained 2,5-bis(aminomethyl)furan reaction solution was then subjected to solid-liquid separation to obtain a 2,5-bis(aminomethyl)furan solution and solid D. Solid D was washed with an alcoholic solution of hydrochloric acid to recover the catalyst and obtain a washing liquid. The washing liquid was converted under an ammonia atmosphere, and at least one of sodium hydroxide or potassium hydroxide was added to continue the reaction, precipitating phthalimide salt, which can be used as a raw material for preparing intermediate products. This method utilizes widely available and renewable reaction raw materials, features a simple and efficient reaction process, mild reaction conditions, simple product separation and purification, simple catalyst preparation, and recyclable catalyst. The product purity after separation and recrystallization purification exceeds 99.9%, and the phthalimide salt raw material can be recycled, showing great application potential. Detailed Implementation

[0032] To make the objectives, technical solutions, and advantages of this invention clearer, the following embodiments further illustrate the invention. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Rather, this invention encompasses any substitutions, modifications, equivalent methods, and solutions made within the spirit and scope of the invention as defined in the claims. Methods not specifically described in this embodiment can be achieved using conventional techniques in the art.

[0033] This invention proposes a technical route for preparing 2,5-di(aminomethyl)furan using 5-chloromethylfurfural as a raw material. 5-Chloromethylfurfural can be prepared with reference to invention patents such as CN202310101639.8 and CN201910477157.6. This invention effectively avoids the problem of easy polymerization of intermediates in the reaction process when using 5-hydroxymethylfurfural and its derivatives as raw materials, and is of great significance for the development of efficient synthesis technology for 2,5-di(aminomethyl)furan.

[0034] The embodiments of the present invention include the following steps:

[0035] (1) 0.001–1.0 g / mL of 5-chloromethylfurfural and 0.001–1.5 g / mL of phthalimide salt were added to a 25 mL round-bottom flask, along with 5 mL of reaction solvent A. The mixture was heated to reflux and maintained for a certain period. After the reaction was complete, stirring was stopped, and the mixture was cooled to room temperature. Excess water was added to precipitate the solid, which was then filtered and dried below 60 °C to obtain intermediate product A. Samples were taken for analysis. Qualitative analysis of the product was performed using gas chromatography-mass spectrometry (GC-MS), and quantitative analysis was performed using GC. The results are shown in Table 1.

[0036] In step (1), the intermediate product yield is calculated as a molar yield based on the substrate 5-chloromethylfurfural.

[0037] Table 1

[0038]

[0039] In Table 1, the phthalimide salt used in the first 5 groups of experiments was potassium phthalimide, and the phthalimide salt used in the last 5 groups of experiments was sodium phthalimide.

[0040] (2) Add 0.001–1.0 g / mL of the intermediate product from step (1), 0.00–1.0 g / mL of reagent B, 0.001–8.0 mol / L of reagent C, 10 mL of reaction solvent B, and hydrogenation catalyst B to a sealed reactor. Replace the air in the reactor with hydrogen three times and then purge with hydrogen to the target pressure. If reagent C is ammonia, replace the air in the reactor with ammonia three times first, then purge with ammonia to the target pressure, and then purge with hydrogen to the target pressure. Then heat to the target temperature, stir rapidly, and maintain for the set time. After the reaction is complete, stop stirring, cool to room temperature, and purge the gas from the reactor to obtain a reaction solution containing 2,5-bis(aminomethyl)furan.

[0041] Hydrogenation catalyst B is a Raney-type catalyst, such as Raney nickel, Raney cobalt, or Raney copper, or a supported catalyst composed of an active component and a supporting agent. It can be prepared by the commonly used impregnation method, in which the active component and the supporting agent are mixed in an aqueous solution, the mixture is stirred at room temperature for a certain period of time, and then subjected to rotary evaporation and drying. After that, it is successively oxidized in a muffle furnace at 200–600°C and calcined and reduced in a tube furnace at 400–800°C in a hydrogen atmosphere to obtain the supported hydrogenation catalyst B. It is then ground into powder and stored in an inert atmosphere for use.

[0042] The present invention is described in detail below with specific implementation methods and examples. The raw materials used are the intermediate products obtained from the reactions in Table 1, and the reaction numbers correspond accordingly. For example, the intermediate product obtained from reaction number 1 in Table 1 is used in experiment number 1 in Table 2, and so on. Qualitative analysis of the products was performed using gas chromatography-mass spectrometry, and product quantification was completed by gas chromatography. The yield was calculated based on the molar yield of intermediate product A. The results are shown in Table 2.

[0043] The catalyst content and yield are relative to the content and yield of the substrate 5-chloromethylfurfural. This invention provides a highly efficient and high-yield method, with easily separable catalysts, a mild reaction system, and easily purified products with a purity of up to 99.9%. The implementation of this invention is not limited to the examples described above.

[0044] (3) Centrifuge the reaction solution obtained in (2) to recover solid D, and further recover the reaction solvent by vacuum distillation of the obtained 2,5-bis(aminomethyl)furan solution to obtain crude 2,5-bis(aminomethyl)furan product. Then add dichloromethane and water that is immiscible with dichloromethane to extract 2,5-bis(aminomethyl)furan into the aqueous phase. Separate the extraction layer and recover the extractant. Obtain pure 2,5-bis(aminomethyl)furan product by recrystallization.

[0045] (4) The solid D obtained in (3) is washed with an alcoholic solution of hydrochloric acid to recover the catalyst and obtain a washing liquid. The washing liquid and ammonia gas at 0.2-0.9 MPa are injected into the reactor and reacted at a certain temperature for a certain time. After the reaction is completed, at least one of sodium hydroxide or potassium hydroxide at 0.001-1.0 g / mL is added and the reaction is continued for a period of time to precipitate phthalimide salt, which can be used as the raw material for step (1).

[0046] The invention is further described in detail below with specific implementation methods and examples. The raw material used is solid D separated from the solution after reaction by centrifugation in Table 2, and the reaction numbers correspond accordingly. For example, solid D separated from the solution after reaction number 1 in Table 2 is used in experiment number 1 in Table 3, and so on. Qualitative analysis of the product is performed using liquid chromatography-mass spectrometry, and product quantification is performed by liquid chromatography. The yield is calculated based on the molar yield of intermediate product A. The results are shown in Table 3.

[0047] Table 2

[0048]

[0049] Table 3

[0050]

[0051] The implementation of this invention is not limited to the above examples. The reaction raw materials used in the method of this invention are widely available and renewable. The reaction process is simple and efficient, the reaction conditions are mild, the product separation and purification are simple, the catalyst preparation is simple, and the catalyst can be recycled and reused. The purity of the product after separation and recrystallization purification exceeds 99.9%, and the phthalimide salt raw material can be recycled, showing great application prospects.

Claims

1. A method for preparing 2,5-di(aminomethyl)furan from 5-chloromethylfurfural, characterized in that... Includes the following steps: 1) The reaction substrate 5-chloromethylfurfural and phthalimide salt were added to the reaction solvent A, heated for a period of time and then cooled to room temperature. Water was added to the reaction solution to precipitate the solid, which was then filtered and dried to obtain the intermediate product. 2) The intermediate product obtained in step 1), the reaction reagent, the catalyst and the reaction solvent B are mixed and added to the reaction vessel. Hydrogen gas at a certain pressure is introduced and the reaction is heated in a sealed manner for a period of time. Then it is cooled to room temperature to obtain 2,5-di(aminomethyl)furan. 3) The 2,5-bis(aminomethyl)furan reaction solution obtained after the reaction in step 2) is subjected to solid-liquid separation to obtain a 2,5-bis(aminomethyl)furan solution and solid D. The obtained 2,5-bis(aminomethyl)furan solution is subjected to vacuum distillation to recover the reaction solvent B, and crude 2,5-bis(aminomethyl)furan product is obtained. Then, dichloromethane and water are added to the crude 2,5-bis(aminomethyl)furan product, mixed thoroughly, and allowed to stand for separation. The dichloromethane layer is separated and the solvent is recovered. The aqueous phase is crystallized to obtain the solid product 2,5-bis(aminomethyl)furan. 4) Wash the solid D obtained in step 3) with an alcoholic solution of hydrochloric acid to recover the catalyst and obtain the washing liquid. Inject the washing liquid into the reactor, purge it with ammonia gas at a certain pressure, and react at a certain temperature for a certain time. After the reaction is completed, add at least one of sodium hydroxide or potassium hydroxide and keep it warm to continue the reaction for a period of time to precipitate phthalimide salt, which can be reused as the raw material in step 1). The reaction reagent includes a first reaction reagent, which includes at least one of hydroxylamine aqueous solution, hydrazine hydrate, hydroxylamine hydrochloride, hydroxylamine sulfate, ammonia gas, ammonia water, and a methanol or ethanol solution of ammonia. The catalyst is a Raney type catalyst or a supported catalyst composed of an active component and a support. The Raney-type catalyst is selected from Raney nickel, Raney cobalt, and Raney copper; the supported catalyst has an active component of at least one of Ni, Cu, Co, Cr, Sn, Al, Bi, Ce, Pt, Pd, Au, Ag, Rh, Ru, Ir, Re, and Fe, and the support is a metal oxide of at least one of CaO, MgO, La2O3, Y2O3, SiO2, ZSM, HZSM, CeO2, ZrO2, Al2O3, TiO2, Nb2O5, SnO2, V2O5, MnO2, Fe2O3, Fe3O4, and MoO3; In step 1), the reaction temperature is 20–160℃, the reaction time is 0.25–48 h, the mass concentration of the reaction substrate 5-chloromethylfurfural is 0.001–1.0 g / mL, and the mass concentration of the phthalimide salt is 0.001–1.5 g / mL. In step 2), the partial pressure of hydrogen is 0.25–5.0 MPa; the reaction temperature is 30–200 °C; the reaction time is 0.25–48 h; the mass concentration of the intermediate product is 0.001–1.0 g / mL; and the molar concentration of the first reaction reagent is 0.001–8.0 mol / L.

2. The method for preparing 2,5-di(aminomethyl)furan from 5-chloromethylfurfural as described in claim 1, characterized in that: In step 2), the reaction reagent further includes a second reaction reagent, which includes one of sodium carbonate, potassium carbonate, calcium carbonate, sodium hydroxide, potassium hydroxide, calcium hydroxide, sodium ethoxide, sodium acetate, potassium acetate, potassium silicate, sodium silicate, hydrochloric acid, sulfuric acid, nitric acid, and acetic acid.

3. The method for preparing 2,5-di(aminomethyl)furan from 5-chloromethylfurfural as described in claim 1, characterized in that: The phthalimide salt is sodium phthalimide or potassium phthalimide; the reaction solvent A is at least one of N,N-dimethylformamide, acetonitrile, toluene, and ethyl acetate; the reaction solvent B is at least one of water, tetrahydrofuran, acetonitrile, diethyl ether, dichloromethane, toluene, ethyl acetate, N,N-dimethylformamide, methanol, or ethanol.

4. The method for preparing 2,5-di(aminomethyl)furan from 5-chloromethylfurfural as described in claim 2, characterized in that: The mass concentration of the second reaction reagent is no greater than 1.0 g / mL.

5. The method for preparing 2,5-di(aminomethyl)furan from 5-chloromethylfurfural as described in claim 1, characterized in that: In step 4), the partial pressure of ammonia gas in the reaction vessel is 0.2–0.9 MPa; the reaction temperature is 60–200℃; the reaction time is 2–48 h; the amount of sodium hydroxide or potassium hydroxide used is 0.001–1.0 g / mL; and the time for continuing the reaction at the specified temperature is 0.25–10 h.

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