Catalyst for the preparation of N-butyl-2,2,6,6-tetramethyl-4-piperidineamine by the reduction of triacetoneamine and its application

Abstract

The present invention relates to a heterogeneous catalyst, specifically to a catalyst for the reduction of triacetoneamine to prepare N-butyl-2,2,6,6-tetramethyl-4-piperidineamine and its application. The preparation of the catalyst includes the synthesis of a micro-mesoporous crystal MMS with a high specific surface area and the loading of an active metal modified by lysine, wherein the loading amount of copper is 0.1-8 wt.%, the loading amount of nickel is 0.01-2 wt.%, and the addition amount of lysine relative to the mass of the carrier is 0.1-5 wt.%. After drying and calcination, the CuNi@MMS catalyst is obtained. Using triacetoneamine, n-butylamine and hydrogen as reactants, the CuNi@MMS catalyst prepared by this application is used to catalytically synthesize N-butyl-2,2,6,6-tetramethyl-4-piperidineamine continuously in a fixed-bed reactor. The yield of the target product of this reaction is high, the post-treatment of the reaction is simple and pollution-free, which is conducive to large-scale continuous production.

Description

Technical Field

[0001] The present invention belongs to the technical field of catalysts, and particularly relates to a catalyst for the reduction of triacetoneamine to prepare N-butyl-2,2,6,6-tetramethyl-4-piperidineamine, a preparation method thereof, and an application thereof. Background Art

[0002] N-butyl-2,2,6,6-tetramethyl-4-piperidineamine is an extremely important synthetic material intermediate in the fine chemical industry, and is widely used in the preparation of various hindered amine light stabilizers (HALS) with excellent properties. Its applications in food packaging, medicine, and resins are also extremely extensive. With the development of China's fine chemical industry, the market demand for N-butyl-2,2,6,6-tetramethyl-4-piperidineamine in the domestic market has also increased rapidly.

[0003] At present, the industrial production methods mostly adopt the batch autoclave method. The catalysts are mostly Raney nickel and Raney copper, and there is also activated carbon supported noble metal Pt. For example, in the preparation process of a light stabilizer intermediate N-butyl-2,2,6,6-tetramethyl-4-piperidineamine in CN201810378003.7, the batch autoclave method is adopted, and the catalyst is Raney nickel or skeletal cobalt. Raney nickel has a large dosage in the batch autoclave production process. In the batch autoclave method, the air in the reaction kettle needs to be replaced each time, and then excessive hydrogen is introduced for pressurized reaction. After the reaction is completed, the hydrogen needs to be vented and the remaining hydrogen in the reaction kettle needs to be replaced. This process has complicated reaction operations, great potential safety hazards in the process, long reaction time, and low production efficiency. In the continuous synthesis method and synthesis device of tetramethylpiperidineamine in CN201910684407.3, the catalyst is any one of skeletal nickel, skeletal copper, and palladium-carbon catalyst. However, Raney nickel or skeletal cobalt catalyst has certain flammability before activation. Therefore, the loading and removal processes need to be operated under strict inert atmosphere, and the powder is not easy to form, which easily leads to blockage of the fixed bed layer. Moreover, these catalysts have limitations such as small specific surface area and small pore volume, and are prone to carbon deposition during the reaction, resulting in blockage and deactivation of the catalyst pores. Therefore, they are not suitable for use in fixed bed reactors. 2 CN00121156.0 discloses a preparation method of 2,2,6,6-tetraalkyl-4-piperidineamine, which uses a fixed bed as the reactor. However, it has the disadvantages of low yield of the target product, many impurities, and high cost. Moreover, this invention requires adding one or more substances as solvents in addition to the reactants to assist the reaction to occur, which not only increases the cost but also increases the probability of impurity generation and the deactivation rate of the catalyst. Therefore, developing an efficient and environmentally friendly catalyst suitable for fixed bed reactors to realize the continuous progress of the reaction process can not only greatly reduce many potential safety hazards in the production process, but also greatly improve production efficiency and reduce product costs.

[0004] CN00121156.0 discloses a method for preparing 2,2,6,6-tetraalkyl-4-piperidineamine, which uses a fixed bed as the reactor, but it has the disadvantages of low yield of the target product, many impurities and high cost. And this invention needs to add one or more substances as solvents in addition to the reactants to assist the reaction to occur, which not only increases the cost but also increases the probability of impurity generation and the deactivation rate of the catalyst. Therefore, developing an efficient and environmentally friendly catalyst suitable for fixed bed reactors to realize the continuous progress of the reaction process can not only greatly reduce many potential safety hazards in the production process, but also greatly improve production efficiency and reduce product costs. Summary of the Invention

[0005] To solve the problems of the current intermittent batch synthesis process of N-butyl-2,2,6,6-tetramethyl-4-piperidineamine, such as high catalytic cost, discontinuous production, large potential safety hazards, and many by-products, and the disadvantages of low yield and many impurities when using a fixed bed as a reactor, the present invention prepares N-butyl-2,2,6,6-tetramethyl-4-piperidineamine by synthesizing a highly efficient CuNi@MMS catalyst suitable for the fixed bed continuous production process.

[0006] The specific preparation method of the catalyst is as follows:

[0007] (1) Preparation method of self-made micro-mesoporous silica crystal MMS: Pipette tetrapropylammonium hydroxide (TPAOH, 25%) into distilled water and mix evenly, denoted as mixed solution A. Then pipette tetraethyl orthosilicate (TEOS) and isopropanol and mix evenly, denoted as mixed solution B. Mix and stir mixed solutions A and B for 3 h, put the obtained gel into a kettle, pre-treat it at 100 °C for 10 h to evaporate the excess water, and then crystallize it at 180 °C for 24 - 48 h. After crystallization, wash it with water, filter it, dry it overnight in an oven at 110 °C, and finally calcine it at high temperature to obtain the micro-mesoporous silica crystal MMS. The molar ratio of each component in the synthesis gel is TEOS:TPAOH:IPA:H 2 O = 1:0.37 - 0.51:1.7:21.3 - 26.1.

[0008] (2) Weigh copper nitrate trihydrate, nickel nitrate hexahydrate, and lysine at room temperature and dissolve them in ethanol to obtain a metal precursor impregnation solution. Perform equal-volume impregnation with the self-made micro-mesoporous silica crystal MMS support, dry it, extrude it into strips, dry it again, and then calcine it in a muffle furnace, and screen to obtain a 20 - 40 mesh catalyst.

[0009] As an improvement of the present invention, the copper loading amount in the catalyst preparation is 0.1 - 8 wt.%, the nickel loading amount is 0.01 - 2 wt.%, and the addition amount of lysine relative to the mass of the support is 0.1 - 5 wt.%. Preferably, the copper loading amount is 1 - 5 wt.%, the nickel loading amount is 0.1 - 1 wt.%, and the addition amount of lysine relative to the mass of the support is 0.1 - 2 wt.%, where the molar ratio is Cu:Ni:Lys = 92.4 - 462:10 - 100:4.01 - 80.2.

[0010] As an improvement of the present invention, the calcination procedure in the catalyst preparation step (1) is: raise the temperature from room temperature to 110 °C at a heating rate of 5 °C / min, and then raise the calcination temperature from 110 °C to 350 - 550 °C at 3 °C / min, and maintain it at this temperature for 1 - 8 h. Preferably, the calcination temperature is 400 - 500 °C, and maintain it at this temperature for 3 - 5 h.

[0011] As an improvement of the present invention, after equal-volume impregnation in the catalyst preparation step (2), it is required to be placed at room temperature for 12 h, then dried in an oven, extruded with water added, dried again, and heated from room temperature to 110 °C in a muffle furnace at a heating rate of 5 °C / min, and then the calcination temperature is raised from 110 °C to 500 °C at 3 °C / min, maintained at this temperature for 5 h, and finally sieved to obtain a 20-40 mesh catalyst.

[0012] The specific surface area of the catalyst is 400-550 (m 2 ·g -1 ) and the pore volume is 0.4-0.6 (cm 2 ·g -1 ).

[0013] The obtained catalyst is used in the reaction of catalytic reduction of triacetoneamine to prepare N-butyl-2,2,6,6-tetramethyl-4-piperidineamine. The application method is as follows: Weigh the catalyst and load it into a fixed-bed micro-reactor, and carry out high-temperature reduction under a H 2 atmosphere. After activation is completed, the temperature is lowered to the reaction temperature, the reaction solution is input through a flow pump, and after the reaction system is stable, the collected product solution is treated by absorbing water with silica gel particles and then analyzed by gas chromatography.

[0014] Among them, the catalyst dosage is 15-25 g; the raw material liquid is a mixed solution of triacetoneamine and n-butylamine (molar ratio 1:1-4); the flow rate of the raw material liquid is 100 mL / h; the reaction temperature is 105-115 °C; the total pressure is 1 MPa; the hydrogen flow rate is 0.5-1.5 L / h.

[0015] Among them, the raw material liquid needs to be stirred and filtered with 40-100 mesh round silica gel particles dried in an oven at 100 °C for water absorption pretreatment.

[0016] The method of the present invention can be illustrated by the following reaction equation:

[0017]

[0018] Beneficial effects: The micro-mesoporous silica crystal MMS prepared by the hydrothermal synthesis method of the present invention has more weak acid sites, and the acid strength of the carrier is relatively low, which can increase the adsorption of n-butylamine on the catalyst, make the reactants fully contact, and is beneficial to improving the selectivity of the target product. Moreover, the active components are evenly distributed on it; there is an electronic interaction between the active metals copper and nickel, which reduces the reduction temperature of the catalyst under a hydrogen atmosphere, reduces the energy consumption in practical applications, the reaction conditions of the invention are mild, the cost is low, and the catalyst and fixed-bed reaction device adopted can realize continuous production, having good industrial application prospects. Description of the Drawings

[0019] Figure 1Yield of N-butyl-2,2,6,6-tetramethyl-4-piperidinamine for 240 h of continuous reaction in Example 1.

[0020] Figure 2 XRD diffraction pattern of the CuNi@MMS catalyst obtained in Example 1. Detailed implementation manners

[0021] Example 1

[0022] (1) Synthesis of MMS micro-mesoporous silica support: Pipette 67.8 mL of tetrapropylammonium hydroxide (TPAOH, 25%) and add it to 36 mL of distilled water and mix evenly, denoted as mixed solution A. Then pipette 50.4 mL of tetraethyl orthosilicate (TEOS) and mix it evenly with 30 mL of isopropanol, denoted as mixed solution B. Mix mixed solutions A and B and stir for 3 h, then put the obtained silica gel into a kettle and pre-crystallize it at 100 °C for 10 h. Then take it out, evaporate the excess water, and then put it into a hydrothermal kettle and crystallize it at 180 °C for 36 h. After crystallization is completed, wash it with water, filter it, and dry it overnight in an oven at 110 °C. Finally, heat it from room temperature to 110 °C at a heating rate of 5 °C / min, and then raise the calcination temperature from 110 °C to 500 °C at a rate of 3 °C / min and calcine it at high temperature for 5 h to obtain MMS molecular sieve. The molar ratio of each component in the gel is TEOS:TPAOH:IPA:H 2 O = 1:0.37:1.7:21.3.

[0023] (2) Loading of copper and nickel on MMS molecular sieve: Weigh 4.8 g of copper nitrate trihydrate, 1.25 g of nickel nitrate hexahydrate and 0.5 g of lysine at room temperature and dissolve them in 9 g of ethanol to obtain a metal precursor impregnation solution, where the molar ratio of Cu:Ni:Lys = 462:100:80.2. Weigh 25 g of the MMS prepared in the above step and perform equal-volume impregnation. After drying in an oven at 110 °C for 12 h, the obtained powder is mixed evenly with a small amount of water, then extruded, dried, and heated in a muffle furnace from room temperature to 110 °C at a heating rate of 5 °C / min, and then raise the calcination temperature from 110 °C to 500 °C at a rate of 3 °C / min and calcine it at high temperature for 5 h. Finally, sieve to obtain 20-40 mesh granular catalyst.

[0024] (3) Reduction of triacetoneamine to N-butyl-2,2,6,6-tetramethyl-4-piperidinamine: Weigh 15 g of the above catalyst and load it into a fixed-bed reactor. In H 2Under an atmosphere, reduce at 220 °C for 3 h. When the temperature is lowered to the reaction temperature of 110 °C, while the hydrogen flow rate is 1 L / h and the reaction pressure is 1 MPa, add the mixture of reactants (the molar ratio of triacetoneamine to n-butylamine is 1:3, which is prepared and pretreated by water absorption and filtration) into the reactor at a flow rate of 100 mL / h to start the reaction. After the reaction is stable, collect the reaction product (the product is pretreated with silica gel particles) and analyze it by gas chromatography. After continuous operation for 240 h, the product yield is 96.6%.

[0025] Example 2

[0026] Change 67.8 mL of tetrapropylammonium hydroxide in step (1) to 93.7 mL of tetrapropylammonium hydroxide, and other operations are the same as in Example 1. After the reaction is stable, collect the reaction product (the product is pretreated with silica gel particles) and analyze it by gas chromatography. After continuous operation for 240 h, the product yield is 96.1%. The molar ratio of each component in the gel is TEOS:TPAOH:IPA:H 2 O = 1:0.51:1.7:26.1.

[0027] Example 3

[0028] Change 4.8 g of copper nitrate trihydrate in step (2) to 0.96 g of copper nitrate trihydrate, where the molar ratio of Cu:Ni:Lys = 92.4:100:80.2, and other operations are the same as in Example 1. After the reaction is stable, collect the reaction product (the product is pretreated with silica gel particles) and analyze it by gas chromatography. After continuous operation for 240 h, the product yield is 95.8%.

[0029] Example 4

[0030] Change 1.25 g of nickel nitrate hexahydrate in step (2) to 0.125 g of nickel nitrate trihydrate, where the molar ratio of Cu:Ni:Lys = 462:10:80.2, and other operations are the same as in Example 1. After the reaction is stable, collect the reaction product (the product is pretreated with silica gel particles) and analyze it by gas chromatography. After continuous operation for 240 h, the product yield is 95.6%.

[0031] Example 5

[0032] Change 0.5 g of lysine in step (2) to 0.025 g of lysine, where the molar ratio of Cu:Ni:Lys = 462:100:4.01, and other operations are the same as in Example 1. After the reaction is stable, collect the reaction product (the product is pretreated with silica gel particles) and analyze it by gas chromatography. After continuous operation for 240 h, the product yield is 95.1%.

[0033] Example 6

[0034] Change the calcination temperature in step (2) to 400 °C, and other operations are the same as in Example 1. After the reaction stabilizes, collect the reaction product (the product is pretreated with silica gel particles) and analyze it by gas chromatography. After continuous operation for 240 h, the product yield is 96.2%.

[0035] Example 7

[0036] Change the calcination temperature in step (2) to 450 °C, and other operations are the same as in Example 1. After the reaction stabilizes, collect the reaction product (the product is pretreated with silica gel particles) and analyze it by gas chromatography. After continuous operation for 240 h, the product yield is 96.7%.

[0037] Example 8

[0038] Change the calcination time in step (2) to 3 h, and other operations are the same as in Example 1. After the reaction stabilizes, collect the reaction product (the product is pretreated with silica gel particles) and analyze it by gas chromatography. After continuous operation for 240 h, the product yield is 96.5%.

[0039] Example 9

[0040] Change the calcination time in step (2) to 4 h, and other operations are the same as in Example 1. After the reaction stabilizes, collect the reaction product (the product is pretreated with silica gel particles) and analyze it by gas chromatography. After continuous operation for 240 h, the product yield is 96.7%.

[0041] Example 10

[0042] Change the 15 g catalyst in step (3) to 20 g catalyst, and other operations are the same as in Example 1. After the reaction stabilizes, collect the reaction product (the product is pretreated with silica gel particles) and analyze it by gas chromatography. After continuous operation for 240 h, the product yield is 97.7%.

[0043] Example 11

[0044] Change the 15 g catalyst in step (3) to 25 g catalyst, and other operations are the same as in Example 1. After the reaction stabilizes, collect the reaction product (the product is pretreated with silica gel particles) and analyze it by gas chromatography. After continuous operation for 240 h, the product yield is 97.5%.

[0045] Example 12

[0046] Change the reaction temperature in step (3) to 105 °C, and other operations are the same as in Example 1. After the reaction stabilizes, collect the reaction product (the product is pretreated with silica gel particles) and analyze it by gas chromatography. After continuous operation for 240 h, the product yield is 96.1%.

[0047] Example 13

[0048] Change the reaction temperature in step (3) to 115 °C, and other operations are the same as in Example 1. After the reaction stabilizes, collect the reaction product (the product is pretreated with silica gel particles) and analyze it by gas chromatography. After continuous operation for 240 h, the product yield is 96.8%.

[0049] Example 14

[0050] Change the molar ratio of triacetoneamine to n-butylamine in the raw material liquid in step (3) to 1:1, and other operations are the same as in Example 1. After the reaction stabilizes, collect the reaction product (the product is pretreated with silica gel particles) and analyze it by gas chromatography. After continuous operation for 240 h, the product yield is 95.3%.

[0051] Example 15

[0052] Change the molar ratio of triacetoneamine to n-butylamine in the raw material liquid in step (3) to 1:4, and other operations are the same as in Example 1. After the reaction stabilizes, collect the reaction product (the product is pretreated with silica gel particles) and analyze it by gas chromatography. After continuous operation for 240 h, the product yield is 97.2%.

[0053] Example 16

[0054] Change the hydrogen flow rate in step (3) to 0.5 L / h, and other operations are the same as in Example 1. After the reaction stabilizes, collect the reaction product (the product is pretreated with silica gel particles) and analyze it by gas chromatography. After continuous operation for 240 h, the product yield is 96.0%.

[0055] Example 17

[0056] Change the hydrogen flow rate in step (3) to 1.5 L / h, and other operations are the same as in Example 1. After the reaction stabilizes, collect the reaction product (the product is pretreated with silica gel particles) and analyze it by gas chromatography. After continuous operation for 240 h, the product yield is 97.1%.

[0057] Comparative Example 1

[0058] (1) Synthesis of MMS micro-mesoporous silica support: Pipette 67.8 mL of tetrapropylammonium hydroxide (TPAOH, 25%) and add it to 33 mL of distilled water and mix well, denoted as mixed solution A. Then pipette 50.4 mL of tetraethyl orthosilicate (TEOS) and mix it with 30 mL of isopropanol evenly, denoted as mixed solution B. Mix mixed solutions A and B and stir for 3 h, and put the obtained silica gel into the autoclave for precrystallization at 100 °C for 10 h, then take it out, evaporate the excess water, and then put it into the hydrothermal autoclave for crystallization at 180 °C for 36 h. After crystallization is completed, wash with water, filter, dry overnight in an oven at 110 °C, and finally calcine at 550 °C for 5 h to obtain MMS molecular sieve.

[0059] (2) Copper loading on MMS zeolite: At room temperature, 4.8 g of copper nitrate trihydrate and 0.5 g of lysine were weighed and dissolved in 9 g of ethanol to obtain a metal precursor impregnation solution, where the molar ratio of Cu:Lys = 462:80.2. 25 g of MMS prepared in the above step was weighed for equal-volume impregnation. After drying in an oven at 110 °C for 12 h, the obtained powder was mixed evenly with a small amount of water, extruded, dried, and then calcined in a muffle furnace at a heating rate of 5 °C / min from room temperature to 110 °C, and then the calcination temperature was raised from 110 °C to 500 °C at 3 °C / min for 5 h of high-temperature calcination. Finally, 20 - 40 mesh granular catalyst was obtained by screening.

[0060] (3) Reduction of triacetoneamine to N-butyl-2,2,6,6-tetramethyl-4-piperidineamine: 15 g of the above catalyst was weighed and loaded into a fixed-bed reactor, and reduced in an H 2 atmosphere at 220 °C for 3 h. When the temperature was lowered to the reaction temperature of 110 °C, the mixture of reactants (the molar ratio of triacetoneamine to n-butylamine was 1:3, and after preparation, it was pretreated by water absorption and filtration) was added to the reactor at a flow rate of 100 mL / h at a hydrogen flow rate of 1 L / h and a reaction pressure of 1 MPa to start the reaction. After the reaction was stable, the reaction product (the product was pretreated with silica gel particles) was collected and analyzed by gas chromatography. After continuous operation for 100 h, the product yield was 60.4%.

[0061] Comparative Example 2

[0062] In step (2), 4.8 g of copper nitrate trihydrate was changed to 5.78 g of nickel nitrate hexahydrate, where the molar ratio of Ni:Lys = 462:80.2. Other conditions were the same as in Comparative Example 1. After the reaction was stable, the reaction product (the product was pretreated with silica gel particles) was collected and analyzed by gas chromatography. After continuous operation for 100 h, the product yield was 53.8%.

[0063] Comparative Example 3

[0064] (1) At room temperature, 4.8 g of copper nitrate trihydrate, 1.25 g of nickel nitrate hexahydrate and 0.5 g of lysine were weighed and dissolved in 12.5 g of ethanol to obtain a metal precursor impregnation solution. 25 g of diatomite was weighed for equal-volume impregnation, where the molar ratio of Cu:Ni:Lys = 462:100:80.2. After drying in an oven at 110 °C for 12 h, the obtained powder was mixed evenly with a small amount of water, extruded, dried, and then calcined in a muffle furnace at a heating rate of 5 °C / min from room temperature to 110 °C, and then the calcination temperature was raised from 110 °C to 500 °C at 3 °C / min for 5 h of high-temperature calcination. Finally, 20 - 40 mesh granular catalyst was obtained by screening.

[0065] (2) Reduction of triacetoneamine to N-butyl-2,2,6,6-tetramethyl-4-piperidineamine: 15 g of the above catalyst was weighed and loaded into a fixed-bed reactor, and in H2 Under an atmosphere, reduce at 220 °C for 3 h. When the temperature is lowered to the reaction temperature of 110 °C, while the hydrogen flow rate is 1 L / h and the reaction pressure is 1 MPa, add the mixture of reactants (the molar ratio of triacetoneamine to n-butylamine is 1:3, which is prepared and pretreated by water absorption and filtration) into the reactor at a flow rate of 100 mL / h to start the reaction. After the reaction is stable, collect the reaction product (the product is pretreated with silica gel particles) and analyze it by gas chromatography. After continuous operation for 100 h, the product yield is 20.4%.

[0066] Comparative Example 4

[0067] (1) Weigh 4.8 g of copper nitrate trihydrate, 1.25 g of nickel nitrate hexahydrate and 0.5 g of lysine at room temperature and dissolve them in 15 g of ethanol to obtain a metal precursor impregnation solution. Weigh 25 g of γ-Al 2 O 3 Perform equal-volume impregnation, where the molar ratio Cu:Ni:Lys = Cu:Ni:Lys = 462:100:80.2. After drying the powder obtained by drying in an oven at 110 °C for 12 h and mixing it evenly with a small amount of water, extrude it, dry it, and then raise the temperature from room temperature to 110 °C at a heating rate of 5 °C / min in a muffle furnace, and then raise the calcination temperature from 110 °C to 500 °C at 3 °C / min and calcine at high temperature for 5 h. Finally, screen to obtain 20 - 40 mesh granular catalyst.

[0068] (2) Preparation of N-butyl-2,2,6,6-tetramethyl-4-piperidineamine by reduction of triacetoneamine: Weigh 15 g of the above catalyst and load it into a fixed-bed reactor. Under an H 2 atmosphere, reduce at 220 °C for 3 h. When the temperature is lowered to the reaction temperature of 110 °C, while the hydrogen flow rate is 1 L / h and the reaction pressure is 1 MPa, add the mixture of reactants (the molar ratio of triacetoneamine to n-butylamine is 1:3, which is prepared and pretreated by water absorption and filtration) into the reactor at a flow rate of 100 mL / h to start the reaction. After the reaction is stable, collect the reaction product (the product is pretreated with silica gel particles) and analyze it by gas chromatography. After continuous operation for 100 h, the product yield is 43.1%.

[0069] Comparative Example 5

[0070] (1) Weigh 4.8 g of copper nitrate trihydrate, 1.25 g of nickel nitrate hexahydrate and 0.5 g of lysine at room temperature and dissolve them in 10 g of ethanol to obtain a metal precursor impregnation solution. Weigh 25 g of SiO 2Equal-volume impregnation was carried out, where the molar ratio of Cu:Ni:Lys = Cu:Ni:Lys = 462:100:80.2. The powder obtained after drying in an oven at 110 °C for 12 h was mixed evenly with a small amount of water, then extruded, dried, and calcined in a muffle furnace at a heating rate of 5 °C / min from room temperature to 110 °C, and then the calcination temperature was raised from 110 °C to 500 °C at 3 °C / min for 5 h of high-temperature calcination. Finally, 20-40 mesh granular catalysts were obtained by screening.

[0071] (2) Preparation of N-butyl-2,2,6,6-tetramethyl-4-piperidineamine by reduction of triacetoneamine: Weigh 15 g of the above catalyst and load it into a fixed-bed reactor. Reduce it in an H 2 atmosphere at 220 °C for 3 h. When the temperature is lowered to the reaction temperature of 110 °C, the mixture of reactants (the molar ratio of triacetoneamine to n-butylamine is 1:3, which is prepared and pretreated by water absorption and filtration) is added to the reactor at a flow rate of 100 mL / h at a hydrogen flow rate of 1 L / h and a reaction pressure of 1 MPa to start the reaction. After the reaction is stable, collect the reaction product (the product is pretreated with silica gel particles) and analyze it by gas chromatography. After continuous operation for 100 h, the product yield is 77.8%.

[0072] Comparative Example 6

[0073] (1) At room temperature, weigh 4.8 g of copper nitrate trihydrate, 1.25 g of nickel nitrate hexahydrate, and 0.5 g of lysine and dissolve them in 15 g of ethanol to obtain a metal precursor impregnation solution. Weigh 25 g of ETS-10 for equal-volume impregnation, where the molar ratio of Cu:Ni:Lys = Cu:Ni:Lys = 462:100:80.2. The powder obtained after drying in an oven at 110 °C for 12 h was mixed evenly with a small amount of water, then extruded, dried, and calcined in a muffle furnace at a heating rate of 5 °C / min from room temperature to 110 °C, and then the calcination temperature was raised from 110 °C to 500 °C at 3 °C / min for 5 h of high-temperature calcination. Finally, 20-40 mesh granular catalysts were obtained by screening.

[0074] (2) Preparation of N-butyl-2,2,6,6-tetramethyl-4-piperidineamine by reduction of triacetoneamine: Weigh 15 g of the above catalyst and load it into a fixed-bed reactor. Reduce it in an H 2 atmosphere at 220 °C for 3 h. When the temperature is lowered to the reaction temperature of 110 °C, the mixture of reactants (the molar ratio of triacetoneamine to n-butylamine is 1:3, which is prepared and pretreated by water absorption and filtration) is added to the reactor at a flow rate of 100 mL / h at a hydrogen flow rate of 1 L / h and a reaction pressure of 1 MPa to start the reaction. After the reaction is stable, collect the reaction product (the product is pretreated with silica gel particles) and analyze it by gas chromatography. After continuous operation for 100 h, the product yield is 81.2%.

[0075] Table 1: Textural property parameters of the catalysts in the examples

[0076]

[0077] Although the embodiments of the present invention have been described in detail, it should be understood that various changes, substitutions, and alterations can be made to the embodiments of the present invention without departing from the spirit and scope of the present invention.

Claims

1. A copper-based MMS catalyst for the reduction of triacetoneamine to prepare N-butyl-2,2,6,6-tetramethyl-4-piperidineamine, characterized in that: The preparation steps of the catalyst are as follows: (1)Preparation method of micro-mesoporous silica crystal MMS: Pipette tetrapropylammonium hydroxide and add it to distilled water and mix evenly, denoted as mixed solution A. Then pipette tetraethyl orthosilicate and isopropanol and mix evenly, denoted as mixed solution B. Mix and stir mixed solutions A and B, put the obtained gel into a kettle for pre-crystallization, evaporate the excess water, and then carry out a crystallization reaction. After the crystallization is completed, wash with water, filter, dry, and calcine to obtain the micro-mesoporous silica crystal MMS, where the molar ratio of each component in the gel is TEOS:TPAOH:IPA:H 2 O = 1:0.37 - 0.51:1.7:21.3 - 26.1; (2) Loading of copper and nickel on the micro-mesoporous silica crystal MMS support: Weigh copper salt, nickel salt and lysine at room temperature and dissolve them in ethanol to obtain a metal precursor impregnation solution. The micro-mesoporous silica crystal MMS is impregnated with an equal volume, dried, extruded, dried again, and then calcined in a muffle furnace, and screened to obtain the catalyst.

2. The catalyst according to claim 1, characterized in that: The precrystallization condition in step (1) is precrystallization at 100 °C for 10 h; the crystallization reaction is crystallization at 180 °C for 24 - 48 h.

3. The catalyst according to claim 1, characterized in that: In the preparation of the catalyst, the loading mass of copper is 0.1 - 8 wt.%, the loading mass of nickel is 0.01 - 2 wt.%, and the addition amount of lysine relative to the mass of the support is 0.1 - 5 wt.%.

4. The catalyst according to claim 1, characterized in that: The molar ratio of the raw material components of the catalyst is Cu:Ni:Lys = 0.9~4.6:0.1~1:0.04~0.

8.

5. The catalyst according to claim 1, characterized in that: The calcination in step (1) is as follows: The temperature is raised from room temperature to 110 °C at a heating rate of 5 °C / min, and then the calcination temperature is raised from 110 °C to 350 - 550 °C at a rate of 3 °C / min, and maintained at this temperature for 1 - 8 h.

6. The catalyst according to claim 1, characterized in that: After equal-volume impregnation in step (2), it needs to be placed at room temperature for 12 h, then dried in an oven, extruded with water, dried again, the temperature is raised from room temperature to 110 °C at a heating rate of 5 °C / min in a muffle furnace, and then the calcination temperature is raised from 110 °C to 500 °C at a rate of 3 °C / min, maintained at this temperature for 5 h, and finally screened to obtain a 20 - 40 mesh catalyst.

7. The application of the catalyst according to any one of claims 1 - 6, characterized in that, The catalyst is used in the reaction for catalytic reduction of triacetoneamine to prepare N-butyl-2,2,6,6-tetramethyl-4-piperidineamine.

8. The application according to claim 7, characterized in that: The application method is as follows: Weigh the catalyst and load it into a fixed-bed micro-reactor, and perform high-temperature reduction under an H 2 atmosphere. After activation is completed, the temperature is lowered to the reaction temperature. The raw material liquid is input through a flow pump. After the reaction system is stable, the collected product liquid is treated with silica gel particles to absorb water, and then the conversion of triacetoneamine is analyzed by gas chromatography.

9. The application according to claim 8, characterized in that: The catalyst dosage is 15 - 25 g; the raw material liquid is a mixed solution of triacetoneamine and n-butylamine with a molar ratio of 1:1 - 4; the flow rate of the raw material liquid is 100 mL / h; the reaction temperature is 105 - 115 °C; the total pressure is 1 MPa; the hydrogen flow rate is 0.5 - 1.5 L / h.

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