Method for synthesizing piperidine by taking glutaraldehyde as raw material through catalytic hydroamination

Abstract

The invention discloses a method for synthesizing piperidine through catalytic hydroamination by using glutaraldehyde as a raw material, which comprises the following steps: adding glutaraldehyde and amine into a solvent, uniformly mixing, adding a catalyst, pressurizing to 1.0-8.0 MPa by using hydrogen, heating to 80-150 DEG C, reacting for 3-10 hours, and carrying out hydroamination reaction under the action of the catalyst; after the reaction is completed, separating the catalyst, and rectifying the product to obtain a piperidine product; wherein the solvent is alcohol or ether, the catalyst is a porous metal catalyst or a supported catalyst thereof, and the porous metal catalyst is raney nickel and / or raney cobalt; the supported catalyst takes at least one of transition metals nickel, cobalt and ruthenium as an active component. The method has the advantages of extremely simple process, loose reaction conditions, low production cost, high efficiency, high glutaraldehyde conversion rate and high piperidine selectivity.

Description

Technical Field

[0001] The invention relates to the technical field of piperidine preparation, in particular to a method for synthesizing piperidine by catalytic hydrogen amination using glutaraldehyde as a raw material. Background Art

[0002] The chemical formula of piperidine is C5H5N, which is a typical aromatic amine. It is a colorless liquid with a special smell. Piperidine is weakly alkaline, with a molecular weight of 79.10g / mol, a density of 0.982g / cm3, a boiling point of 115-116℃, and a melting point of -42℃.

[0003] Piperidine is an important organic synthesis intermediate, which has a wide range of applications in the fields of medicine, pesticides, dyes and polymer materials. Piperidine can be synthesized by a variety of methods, such as pyridine catalytic hydrogenation, cyanide hydrolysis, dinitrile hydrogenation, diamine cyclization, etc. For example, the paper "Process Research on the Synthesis of Piperidine by Catalytic Hydrogenation of Pyridine" (Fang Hongxin et al., Anhui Chemical Industry, 2018) introduces the method of synthesizing piperidine by high-pressure hydrogenation of pyridine under Raney nickel catalysis, and investigates the influence of process parameters. Under the optimized process conditions, the conversion rate of piperidine is 90%, the selectivity is 100%, and the comprehensive yield reaches 90%. Patent CN104844539B "A Method for Preparing Piperidine" discloses a method for preparing piperidine by catalyzing pentamethylenediamine with a modified molecular sieve catalyst, and the piperidine selectivity reaches more than 98%. Among them, pyridine hydrogenation is also the current industrial production method of piperidine, which is usually reacted at 7MPa and about 200℃, and the reaction conditions are relatively harsh. At the same time, since the raw material pyridine is difficult to convert completely, it forms an azeotropic system with piperidine, which makes distillation separation difficult. The technical route of producing piperidine using pentamethylenediamine as raw material has been reported for a long time. However, due to the scarcity and high price of pentamethylenediamine raw material itself, and the high cost of the precious metal catalyst or molecular sieve catalyst used, the production cost of piperidine is also high, making it difficult to produce on a large scale industrially.

[0004] Based on the above reasons, the current production cost of piperidine is generally high, with the publicly disclosed market price reaching more than 50,000 yuan / ton. It is urgent to find more advanced technical routes to reduce the production cost of piperidine in order to promote the development of downstream industries. Summary of the invention

[0005] The purpose of the present invention is to solve the above technical problems and provide a method for synthesizing piperidine by catalytic hydrogen amination using glutaraldehyde as a raw material, which has extremely simple process, loose reaction conditions, low production cost, high efficiency, glutaraldehyde conversion rate and piperidine selectivity both close to 100%, and easy product separation.

[0006] Glutaraldehyde and amine are added to a solvent and mixed evenly, a catalyst is then added, the mixture is pressurized to 1.0-8.0 MPa with hydrogen, the temperature is raised to 80-150° C. and the mixture is reacted for 3-10 hours, and a hydrogen amination reaction is performed under the action of the catalyst; after the reaction is completed, the catalyst is separated, and the product is distilled to obtain a piperidine product;

[0007] Wherein, the solvent is alcohol or ether, the catalyst is a porous metal catalyst or a supported catalyst thereof, the porous metal catalyst is Raney nickel and / or Raney cobalt; the supported catalyst is a supported catalyst having at least one of transition metals nickel, cobalt and ruthenium as an active component.

[0008] The glutaraldehyde is in the form of an aqueous solution or a crystal.

[0009] The molar ratio of glutaraldehyde to amine is (5:1) to (20:1), preferably (10:1) to (20:1).

[0010] The molar ratio of the catalyst to glutaraldehyde is (1:1) to (1:10), preferably (1:1) to (1:5).

[0011] The mass ratio of the glutaraldehyde to the solvent is (1:40) to (1:120).

[0012] The alcohol is at least one of methanol, ethanol, isopropanol or n-butanol; the ether is at least one of tetrahydrofuran, isopropyl ether, methyl tert-butyl ether or diethyl ether.

[0013] The preparation method of the supported catalyst is

[0014] (1) preparing an active component salt solution and a catalyst promoter solution respectively, wherein the active component is a transition metal selected from at least one of the transition metals Ni, Co, and Ru;

[0015] (2) mixing the active component salt solution and the catalyst additive solution uniformly, and adding the dendritic macromolecule to form a hydrogel;

[0016] (3) Immersing the cleaned cordierite honeycomb ceramic carrier in the hydrogel obtained in step (2), taking it out and drying it at 110-120° C. for 8-12 h in an air atmosphere, and then calcining it at 500-600° C. for 4-8 h in an argon atmosphere to obtain a supported catalyst.

[0017] The catalyst promoter is at least one of PtCl4, Cu(NO3)2, and MnCl2, and the loading amount of the catalyst promoter is controlled to be 1-3% of the carrier mass.

[0018] The dendritic macromolecule is a dendritic epoxy resin or a dendritic polyamide amine, and the added amount is 2-5% of the mass of water.

[0019] The loading amount of the transition metal is 10-30% of the carrier mass, and the loading amount of the catalyst promoter is 1-3% of the carrier mass.

[0020] In view of the problems existing in the background technology, the inventor has made the following improvements:

[0021] (1) The reaction catalyst adopts a porous metal catalyst or a supported catalyst thereof, wherein the porous metal catalyst is Raney nickel and / or Raney cobalt; the supported catalyst is a supported catalyst with at least one of transition metal nickel, cobalt, and ruthenium as an active component. Metal Ni, Co, and Ru can provide a suitable reducing environment, promote the nucleophilic attack between the hydrogen anion of the aldehyde and the nitrogen atom of the amine, and then achieve stereoselectivity, so that it has high activity for the hydrogen amination of alcohols and aldehydes, and can realize the one-step preparation of piperidine, which can not only improve the glutaraldehyde conversion rate and piperidine selectivity, but also accelerate the reaction rate, making the reaction conditions more relaxed, the reaction pressure can be 1.0-8.0MPa, the temperature is 80-150°C, and the reaction pressure is further preferably 1.0-4.0MPa, and the reaction temperature is 80-120°C. The pressure and temperature of the catalytic reaction are lower than those of the prior art, and the reaction can be carried out in a kettle reactor or a fixed bed reactor, with low process operation difficulty, equipment investment and production cost, and easy industrial implementation, especially suitable for large-scale production.

[0022] (2) In the preparation of supported catalysts, cordierite honeycomb ceramics are used as carriers, which have the advantages of good thermal stability, strong adsorption of active substances and good dispersibility. According to the activity and adsorption characteristics of the active substances, the pore size of the carrier surface is preferably controlled to be 10-20 microns. If the pore size is too large, the catalyst will be insufficiently supported and easy to fall off, while if the pore size is too small, it will be difficult to adsorb the catalyst, thereby affecting the catalytic effect. The loading amount of transition metal is controlled at 20-30% of the carrier mass. Too much will make it difficult to load all of it on the carrier, while too little will lead to insufficient active sites, affecting the catalyst performance. The active component salt is a transition metal nitrate, sulfate, hydrochloride, acetate, oxalate, etc.; the catalyst additive is at least one of PtCl4, Cu(NO3)2, and MnCl2. Such additives have certain activity and are cross-distributed with the active component, which can play a synergistic catalytic role and improve the performance and stability of the catalyst; the carrier is impregnated in the form of a hydrogel formed by dendritic macromolecules. The dendritic macromolecules are used as binders to effectively increase the loading amount of the active component, and after carbonization, a mesoporous carbon skeleton is formed, which can prevent the loss of active components and help to extend the service life of the catalyst. The dendritic macromolecules are preferably dendritic epoxy resins and dendritic polyamide amines.

[0023] The invention uses glutaraldehyde as a raw material, adopts a porous metal catalyst or a supported catalyst thereof, and synthesizes piperidine by catalytic hydrogen amination in a one-step process, has a short production cycle and low cost, and according to calculation, the cost of an industrial production route of producing vinyl methyl ether by a carbide acetylene method, producing acrolein by oxidizing propylene, and then producing glutaraldehyde by hydrolysis of methoxydihydropyran can be reduced to less than 10,000 yuan / ton, which is much lower than the production cost of pyridine used in a traditional route, and is even lower than the cost of pentamethylenediamine which has not yet been industrially produced on a large scale. The catalyst used is a non-precious metal catalyst with low cost, and the catalyst recovery is simple and can be reused, which further reduces the production cost, and the glutaraldehyde conversion rate is high, the piperidine selectivity is high, the product separation is easy, and the product quality is high, which is particularly suitable for large-scale production. DETAILED DESCRIPTION

[0024] In order to facilitate the understanding of the present invention, the present invention lists the following embodiments. It should be understood by those skilled in the art that the embodiments are only to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0025] In the embodiments of the present invention, the hydroamination reaction of glutaraldehyde is carried out in a high temperature and high pressure reactor and a fixed bed reaction device in the laboratory. The composition of the reaction product is determined by gas chromatograph (Agilent 7890A, polar capillary column) and gas chromatography-mass spectrometry.

[0026] Embodiment 1:

[0027] Add 300g methanol, 5g glutaraldehyde (50wt% aqueous solution) and 0.15g Raney nickel catalyst into a 1L high temperature and high pressure reactor and seal it. First, replace it with N2 for 3 times, then replace it with H2 for 3 times, and keep the reactor at a slightly positive pressure. Pass 8.5g NH3 into the reactor and pressurize it to 6MPa with H2. Turn on the electric heating, program the temperature to 150℃, and stop the reaction after 10h of reaction. Distill out the excess ammonia, filter and separate the catalyst after cooling, and analyze the product by gas chromatography. The results show that the conversion rate of glutaraldehyde is 96.5%, and the selectivity of piperidine is 96.6%. The product is distilled and separated to obtain a piperidine product.

[0028] Embodiment 2:

[0029] Add 300g methanol, 5g glutaraldehyde (50wt% aqueous solution) and 1.46g Raney nickel catalyst into a 1L high temperature and high pressure reactor and seal it. First, replace it with N2 for 3 times, then replace it with H2 for 3 times, and keep the reactor at a slightly positive pressure. Pass 2.1g NH3 into the reactor and pressurize it to 10MPa with H2. Turn on the electric heating, program the temperature to 100°C, and stop the reaction after reacting for 3h. Distill off the excess ammonia, filter and separate the catalyst after cooling, and analyze the product by gas chromatography. The results show that the conversion rate of glutaraldehyde is 98.7%, and the selectivity of piperidine is 98.2%. The separated product is distilled and separated to obtain a piperidine product.

[0030] Embodiment 3:

[0031] Add 300g methanol, 5g glutaraldehyde (50wt% aqueous solution) and 0.7g Raney nickel catalyst into a 1L high temperature and high pressure reactor and seal it. First, replace it with N2 for 3 times, then replace it with H2 for 3 times, and keep the reactor slightly positive. Pass 4.3g NH3 into the reactor and pressurize it to 3MPa with H2. Turn on the electric heating, program the temperature to 120℃, and stop the reaction after reacting for 10h. Distill out the excess ammonia, filter and separate the catalyst after cooling, and analyze the product by gas chromatography. The results show that the conversion rate of glutaraldehyde is 99.5%, and the selectivity of piperidine is 97.6%. The separated product is distilled and separated to obtain the piperidine product.

[0032] Embodiment 4:

[0033] Add 300g of isopropanol, 10g of glutaraldehyde (50wt% aqueous solution) and 2.1g of Raney cobalt catalyst into a 1L high temperature and high pressure reactor and seal it. First, replace it with N2 for 3 times, then replace it with H2 for 3 times, and keep the reactor at a slightly positive pressure. Pass 12.9g of NH3 into the reactor and pressurize it to 2MPa with H2. Turn on the electric heating, program the temperature to 110°C, and stop the reaction after 8h of reaction. Distill out the excess ammonia, filter and separate the catalyst after cooling, and analyze the product by gas chromatography. The results show that the conversion rate of glutaraldehyde is 99.2%, and the selectivity of piperidine is 98.4%. The separated product is distilled and separated to obtain a piperidine product.

[0034] Embodiment 5:

[0035] Add 300g of tetrahydrofuran, 15g of glutaraldehyde (50wt% aqueous solution) and 2.1g of Raney nickel catalyst into a 1L high temperature and high pressure reactor and seal it. First, replace it with N2 for 3 times, then replace it with H2 for 3 times, and keep the reactor slightly positive. Pass 21.5g of NH3 into the reactor and pressurize it to 1MPa with H2. Turn on the electric heating, program the temperature to 100°C, and stop the reaction after 6h of reaction. Distill out the excess ammonia, filter and separate the catalyst after cooling, and analyze the product by gas chromatography. The results show that the conversion rate of glutaraldehyde is 99.3%, and the selectivity of piperidine is 98.2%. The separated product is distilled and separated to obtain the piperidine product.

[0036] Embodiment 6:

[0037] Add 300g methanol, 5g glutaraldehyde (50wt% aqueous solution), 5.6g n-butylamine and 0.7g Raney cobalt catalyst into a 1L high temperature and high pressure reactor, seal it. First, replace it with N2 for 3 times, then replace it with H2 for 3 times, and keep the reactor slightly positive. Pass 4.3g NH 3， The reaction mixture was pressurized to 5 MPa by H2. The electric heating was turned on and the temperature was raised to 80°C. The reaction was stopped after 10 hours of reaction. After cooling, the catalyst was filtered and separated, and the product was analyzed by gas chromatography. The results showed that the conversion rate of glutaraldehyde was 99.2% and the selectivity of piperidine was 97.3%. The separated product was distilled to obtain the piperidine product.

[0038] Example 7: A stainless steel fixed bed reactor with an inner diameter of 20 mm and a length of 800 mm was used. The bottom of the reactor was first filled with 20-40 mesh quartz sand with a height of 25-30 cm, then filled with 100 mL of supported catalyst, and the top was filled with 20-40 mesh quartz sand. The catalyst was reduced under a hydrogen atmosphere.

[0039] A mixed solution of raw materials glutaraldehyde and methanol (20 g glutaraldehyde, 600 g methanol) is pumped into the reaction system at a speed of 1 mL / min through a metering pump, mixed with ammonia, and passed through a catalyst bed from top to bottom to react at 1 MPa and 80° C. to generate the product piperidine. After the reaction system is stable, sampling and analysis are performed. After the reaction is completed, the collected product is distilled and separated to obtain a piperidine product.

[0040] Supported catalyst preparation example 1:

[0041] The catalyst preparation method is as follows: accurately weigh 100g of clean cordierite honeycomb ceramics; weigh 10g Ni(NO3)2 and 15g deionized water to prepare a 40wt% aqueous solution; then weigh 1g PtCl4 and 2.5g deionized water to prepare a 40wt% aqueous solution; mix the Ni(NO3)2 solution and the PtCl4 solution evenly; add 0.875g of dendritic macromolecule PAMAM to the mixed solution, stirring while adding until a gel is formed; immerse the cordierite honeycomb ceramics in the mixed hydrogel, immerse at 80°C for 6h, take out and dry at 120°C for 8h in an air atmosphere, and then calcine at 600°C for 4h in an argon atmosphere to obtain a transition metal-loaded mesoporous monolithic catalyst.

[0042] The catalyst was introduced into Example 5, and samples were taken for analysis after the reaction system was stabilized. The conversion rate of glutaraldehyde was 99.0%, and the selectivity of piperidine was 98.1%.

[0043] Supported catalyst preparation example 2:

[0044] The catalyst preparation method is as follows: accurately weigh 100g of clean cordierite honeycomb ceramics; weigh 30g Co(NO3)2 and 70g deionized water to prepare a 30wt% aqueous solution; then weigh 3g MnCl2 and 7g deionized water to prepare a 30wt% aqueous solution; mix the Co(NO3)2 solution and the MnCl2 solution evenly; add 2.31g of dendritic macromolecule PAMAM to the mixed solution while stirring until a gel is formed; immerse the cordierite honeycomb ceramics in the mixed hydrogel, immerse at 65°C for 8h, take out and dry at 115°C for 8h in an air atmosphere, and then calcine at 550°C for 6h in an argon atmosphere to obtain a transition metal-loaded mesoporous monolithic catalyst.

[0045] The catalyst was introduced into Example 5, and samples were taken for analysis after the reaction system was stabilized. The conversion rate of glutaraldehyde was 99.2%, and the selectivity of piperidine was 97.6%.

[0046] Supported catalyst preparation example 3:

[0047] The catalyst preparation method is as follows: accurately weigh 100g of clean cordierite honeycomb ceramic; weigh 20g Co(NO3)2 and 120g deionized water to prepare a 20wt% aqueous solution; then weigh 3.7g Cu(NO3) 2·2.5g H2O and 11.3g deionized water are prepared into a 20wt% aqueous solution; the two solutions are mixed evenly; 2.64g of dendritic macromolecule PAMAM is added to the mixed solution while stirring until a gel is formed; cordierite honeycomb ceramics are immersed in the mixed hydrogel at 50°C for 10h, taken out and dried at 110°C for 10h in an air atmosphere, and then calcined at 500°C for 8h in an argon atmosphere to obtain a transition metal-loaded mesoporous monolithic catalyst.

[0048] The catalyst was introduced into Example 5, and samples were taken for analysis after the reaction system was stabilized. The conversion rate of glutaraldehyde was 99.6%, and the selectivity of piperidine was 96.5%.

[0049] Supported catalyst preparation example 4:

[0050] The catalyst preparation method is as follows: accurately weigh 100g of clean cordierite honeycomb ceramics; weigh 18g Co(NO3)2, 10g Ni(NO3)2 and 120g deionized water to prepare a 20wt% aqueous solution; then weigh 1g PtCl4, 1g MnCl2 and 8g deionized water to prepare a 20wt% aqueous solution; mix the two solutions evenly; add 5.12g of dendritic macromolecule PAMAM to the mixed solution, stirring while adding until a gel is formed; immerse the cordierite honeycomb ceramics in the mixed hydrogel, immerse at 65°C for 8h, take out and dry at 110°C for 10h in an air atmosphere, and then calcine at 550°C for 8h in an argon atmosphere to obtain a transition metal-loaded mesoporous monolithic catalyst.

[0051] The catalyst was introduced into Example 5, and samples were taken for analysis after the reaction system was stabilized. The conversion rate of glutaraldehyde was 99.5%, and the selectivity of piperidine was 97.8%.

[0052] Supported catalyst comparative example 1:

[0053] The catalyst preparation method is as follows: accurately weigh 100g of calcined silica carrier; weigh 30g Ni(NO3)2 and 70g deionized water to prepare a 30wt% aqueous solution; then weigh 3g MnCl2 and 7g deionized water to prepare a 30wt% aqueous solution; mix the two solutions evenly; immerse the silica carrier in the mixed solution, immerse it at 65°C for 8h, take it out and dry it at 115°C for 8h in an air atmosphere, and then calcine it at 550°C for 6h in an argon atmosphere to obtain a catalyst.

[0054] The catalyst was introduced into Example 5. After the reaction system was stabilized, sampling and analysis showed that the conversion rate of glutaraldehyde was 90.5% and the selectivity of piperidine was 89.8%. After the reaction was completed, the collected product was distilled and separated to obtain a piperidine product.

Claims

1. A method for synthesizing piperidine by catalytic hydroamination using glutaraldehyde as a raw material in a one-step process, characterized in that: Glutaraldehyde and amine are added to a solvent and mixed evenly, a catalyst is then added, the mixture is pressurized to 1.0-8.0 MPa with hydrogen, the temperature is raised to 80-150° C. and the mixture is reacted for 3-10 hours, and a hydrogen amination reaction is performed under the action of the catalyst; after the reaction is completed, the catalyst is separated, and the product is distilled to obtain a piperidine product; Wherein, the solvent is alcohol or ether, the catalyst is a porous metal catalyst or a supported catalyst thereof, the porous metal catalyst is Raney nickel and / or Raney cobalt; the supported catalyst is a supported catalyst having at least one of transition metals nickel, cobalt and ruthenium as an active component.

2. The method for synthesizing piperidine by catalytic hydrogen amination of glutaraldehyde as a raw material as claimed in claim 1, characterized in that: The glutaraldehyde is in the form of an aqueous solution or a crystal.

3. The method for synthesizing piperidine by catalytic hydrogen amination of glutaraldehyde as a raw material as claimed in claim 1, characterized in that: The molar ratio of glutaraldehyde to amine is (5:1) to (20:1).

4. The method for synthesizing piperidine by catalytic hydrogen amination of glutaraldehyde as a raw material as claimed in claim 1, characterized in that: The molar ratio of the catalyst to glutaraldehyde is 1:1 to 1:

10.

5. The method for synthesizing piperidine by catalytic hydrogen amination using glutaraldehyde as a raw material as claimed in claim 1, characterized in that: The mass ratio of the glutaraldehyde to the solvent is 1:40 to 1:

120.

6. The method for synthesizing piperidine by catalytic hydrogen amination using glutaraldehyde as a raw material as claimed in claim 1, characterized in that: The alcohol is at least one of methanol, ethanol, isopropanol or n-butanol; the ether is at least one of tetrahydrofuran, isopropyl ether, methyl tert-butyl ether or diethyl ether.

7. The method for synthesizing piperidine by catalytic hydrogen amination using glutaraldehyde as a raw material as claimed in any one of claims 1 to 6, characterized in that: The preparation method of the supported catalyst is (1) preparing an active component salt solution and a catalyst promoter solution respectively, wherein the active component is a transition metal selected from at least one of the transition metals Ni, Co, and Ru; (2) mixing the active component salt solution and the catalyst additive solution uniformly, and adding the dendritic macromolecule to form a hydrogel; (3) Immersing the cleaned cordierite honeycomb ceramic carrier in the hydrogel obtained in step (2), taking it out and drying it at 110-120° C. for 8-12 h in an air atmosphere, and then calcining it at 500-600° C. for 4-8 h in an argon atmosphere to obtain a supported catalyst.

8. The method for synthesizing piperidine by catalytic hydrogen amination using glutaraldehyde as a raw material as claimed in claim 7, characterized in that: The catalyst promoter is at least one of PtCl4, Cu(NO3)2, and MnCl2, and the loading amount of the catalyst promoter is controlled to be 1-3% of the carrier mass.

9. The method for synthesizing piperidine by catalytic hydrogen amination using glutaraldehyde as a raw material as claimed in claim 7, characterized in that: The dendritic macromolecule is a dendritic epoxy resin or a dendritic polyamide amine, and the added amount is 2-5% of the mass of water.

10. The method for synthesizing piperidine by catalytic hydroamination using glutaraldehyde as a raw material as claimed in claim 7, characterized in that: The loading amount of the transition metal is 10-30% of the carrier mass, and the loading amount of the catalyst promoter is 1-3% of the carrier mass.