Catalyst, preparation method thereof and method for catalytically synthesizing triacetonamine by using catalyst

Abstract

The invention belongs to the technical field of material synthesis, and discloses a catalyst, a preparation method thereof and a method for catalytically synthesizing triacetonamine by using the catalyst. The catalyst comprises a styrene-divinylbenzene copolymer skeleton, acetylacetone metal salt crosslinked on the styrene-divinylbenzene copolymer skeleton through chemical bonds, and acidic sites loaded on the styrene-divinylbenzene copolymer skeleton. The preparation method comprises the following steps: step 1, preparing a styrene-divinylbenzene copolymer skeleton; uniformly stirring styrene or a styrene derivative, divinyl benzene, a pore-foaming agent and an initiator to obtain an oil phase; step 2, dissolving acetylacetone metal salt in a solvent, and uniformly mixing with the oil phase to obtain an oil phase system; step 3, mixing the dispersing agent solution and the polymerization inhibitor solution to obtain a water phase system; step 4, putting the oil-phase system into the water-phase system to prepare resin pellets; step 5, acidification; and 6, washing and drying. When the catalyst disclosed by the invention is used for catalytically synthesizing triacetonamine, the conversion rate is high, and the selectivity is strong.

Description

Technical Field

[0001] This invention relates to the field of materials synthesis technology, and in particular to a catalyst, its preparation method, and a method for catalyzing the synthesis of triacetone amine. Background Technology

[0002] Photoaging and decomposition of polymer materials cause losses to industrial and agricultural production and daily life. Industrially, light stabilizers are added to polymer materials to inhibit aging and extend their service life. Hindered amine light stabilizers (HALS) occupy a large market share both domestically and internationally due to their excellent light-stabilizing effects. Triacetone amine, as the sole precursor for synthesizing hindered piperidine derivatives, determines the development direction of the entire hindered amine light stabilizer industry. Currently, there are two reported methods for synthesizing triacetone amine: the indirect method and the direct method.

[0003] The indirect method uses acetone as a raw material to synthesize intermediates such as diacetone alcohol, acetone ketone, and orlone under the action of a catalyst. These products are then reacted with acetone and ammonia to generate triacetone amine. For example, patents US4252958, US3953459, and US3943139 disclose methods for synthesizing triacetone amine from diacetone alcohol, acetone ketone, and orlone. Although these methods yield good results, the synthesis and separation of acetone ketone, orlone, and diacetone alcohol are difficult. Using these methods significantly increases production steps and costs, and remains far from industrial-scale production.

[0004] The direct method is a method for synthesizing triacetone amine directly from acetone and ammonia in the presence of a catalyst. Compared with the indirect method, this method avoids the separation and purification of intermediate products, significantly reducing production costs. Currently, in industrial production, both domestically and internationally, the commonly used method is to directly produce triacetone amine using acetone and ammonia as raw materials and ammonium nitrate as a catalyst in a high-pressure reactor. This method has a acceptable yield, but the post-processing requires the addition of a large amount of strong alkali to neutralize the ammonium nitrate used as a catalyst, which not only makes post-processing difficult but also poses an explosion hazard. Furthermore, the acquisition of ammonium nitrate, a raw material for explosives, is increasingly subject to control.

[0005] The synthesis of triacetone amine via ion exchange resin has advantages such as simple process, low corrosiveness to equipment, and less waste. It has been studied and developed to some extent in recent years. However, the conversion rate and selectivity in this reaction are still far behind those of existing industrial catalysts. Furthermore, acidic ion exchange resins generally have the disadvantage of poor temperature resistance. Under heating conditions, the acidic groups will gradually fall off, resulting in a continuous decrease in catalytic activity. This not only reduces production efficiency but also affects product quality.

[0006] Therefore, there is an urgent need for a highly efficient catalyst for the synthesis of triacetone amine to achieve safe, green, and continuous production. Summary of the Invention

[0007] The purpose of this invention is to address the technical deficiencies in the prior art by providing a catalyst. This catalyst uses a styrene-divinylbenzene copolymer as its backbone, with an acetylacetone metal salt chemically bonded to the backbone, and acidic sites are also supported on the catalyst.

[0008] Another aspect of the present invention is to provide a method for preparing the catalyst, wherein the method uses styrene or a styrene derivative and divinylbenzene as polymerization precursors, and obtains the desired catalyst through a suspension polymerization process, metal modification, acid treatment, and water washing. This catalyst preparation and use method is simple and environmentally friendly.

[0009] Another aspect of the present invention is to provide a method for the catalytic synthesis of triacetone amine in a fixed bed based on the catalyst. The catalyst exhibits good catalytic activity and selectivity in the fixed-bed synthesis of triacetone amine.

[0010] The technical solution adopted to achieve the purpose of this invention is: A catalyst comprising a styrene-divinylbenzene copolymer backbone, an acetylacetone metal salt crosslinked to the styrene-divinylbenzene copolymer backbone by chemical bonds, and acidic sites supported on the styrene-divinylbenzene copolymer backbone.

[0011] In the above technical solution, the acetylacetone metal salt is iron acetylacetone, copper acetylacetone, nickel acetylacetone, cobalt acetylacetone, or manganese acetylacetone, and the mass of the acetylacetone metal salt is 1% to 10% of the mass of the catalyst.

[0012] Another aspect of the present invention includes a method for preparing the catalyst, comprising the following steps: Step s1: Styrene or styrene derivatives are mixed with divinylbenzene, a porogen, an initiator, an acetylacetone metal salt, and a solvent to obtain an oil phase system. The dispersant and polymerization inhibitor solutions were mixed evenly to obtain an aqueous phase system; Step s2: The oil phase system is added to the aqueous phase system to disperse the oil phase system into uniform droplets. After the reaction is complete, the resin microspheres are obtained by filtration. Step s3: Wash the resin beads and then add an acid solution for acidification to obtain acidified resin beads; Step s4: Wash and dry the acidified resin pellets to obtain the catalyst.

[0013] In the above technical solution, in step s1, styrene or styrene derivatives, divinylbenzene, pore-forming agent and initiator are first stirred evenly to obtain an oil phase; then, acetylacetone metal salt is dissolved in a solvent and mixed evenly with the oil phase to obtain an oil phase system.

[0014] In the above technical solution, in step s1, the molar ratio of styrene or styrene derivative to divinylbenzene is 1:1 to 8:1; The styrene derivative is styrene with an electron-withdrawing group, wherein the electron-withdrawing group is a halogen, nitro, or carbonyl group, and the halogen is fluorine, chlorine, bromine, or iodine. The pore-forming agent is toluene, n-heptane, or a mixture thereof; The initiator is benzoyl peroxide (BPO) or azobisisobutyronitrile (AIBN). The mass fraction of the metal salt of acetylacetone in the solvent is 5-10%; The solvent is ethyl acetate, chloroform, dichloromethane, or tetrahydrofuran; The dispersant is a 1-10% (w / w) polyvinyl alcohol or gelatin solution; The polymerization inhibitor is one of methylene blue and p-tert-butylcatechol.

[0015] In the above technical solution, in step s2, after the oil phase system is added to the aqueous phase system, it is kept at 60~100℃ and stirred for 4~12 hours, and then filtered to obtain resin microspheres.

[0016] In the above technical solution, in step s3, the washing process uses hot water at 50~80℃. After washing the resin beads, add them to the acid solution and stir and heat at 60~120℃ for 12~24 hours to complete the acidification. The acid solution is one or more of sulfuric acid, benzenesulfonic acid, p-chlorobenzenesulfonic acid, and chlorosulfonic acid aqueous solution, the mass fraction of the acid solution is 10-50%, and the volume of the acid solution is 1-10 times the volume of the resin beads.

[0017] In the above technical solution, during step s4, the washing process involves first washing with deionized water until the pH of the washing solution reaches 5-8, and then washing with ethanol.

[0018] Another aspect of the present invention includes a catalyst obtained using the preparation method described above.

[0019] In the above technical solution, the mass percentage of acetylacetone metal salt in the catalyst is 1~10%.

[0020] Another aspect of the invention includes the use of the catalyst in the synthesis of triacetone amine.

[0021] Another aspect of the present invention includes a method for synthesizing triacetone amine in a fixed bed, comprising the following steps: Step 1: The catalyst is loaded into the isothermal zone of an atmospheric pressure fixed-bed reactor equipped with a condenser. Under a flowing N2 atmosphere, the fixed-bed reactor is heated to 40~120℃ and maintained for 1~3 hours. Step 2: After shutting off N2, introduce acetone and ammonia into the fixed-bed reactor at a molar ratio of 3-12:1, with a volume hourly space velocity (VHSV) of 10-100 h⁻¹. -1 ; Step 3: The product is cooled to obtain crude triacetone amine.

[0022] Another aspect of the present invention includes a method for synthesizing triacetone amine in a reaction vessel, comprising the following steps: Step 1: The catalyst and acetone are loaded into the reaction vessel, the gas inside the vessel is replaced with N2 atmosphere, and the temperature of the reaction vessel reactor is raised to 40~120℃. Step 2: Close the N2 gas line, maintain the temperature inside the reactor, and introduce ammonia gas so that the molar ratio of acetone to ammonia gas is 3~12:1; Step 3: Maintain the reaction temperature, turn on the stirrer, and react for 8-16 hours; Step 4: After stopping the reaction, replace the residual ammonia in the reactor with nitrogen. After natural cooling, crude triacetone amine is obtained in the reactor.

[0023] Compared with the prior art, the beneficial effects of the present invention are: (1) By utilizing the suspension polymerization phenomenon in polymer chemical reactions, by adding styrene or styrene derivatives, divinylbenzene, pore-forming agents and initiators to polymerize, a tight three-dimensional cross-linked structure is formed, resulting in polymers with diverse pore structures; at the same time, the metal salt of acetylacetone dissolved in ethyl acetate is loaded into the copolymer backbone through chemical bonds, which is more reliable than the form of impregnation and physical adsorption, and is conducive to improving the reaction selectivity and conversion rate in the synthesis reaction of triacetone amine; (2) The present invention introduces electron-withdrawing groups such as halogen (including fluorine, chlorine, bromine, iodine), nitro or carbonyl groups on the styrene precursor of the polymerization reaction. Through induction effect, conjugation effect and hyperconjugation effect, the electron cloud density of the benzene ring can be reduced, and the temperature resistance and chemical stability of the obtained polymer are significantly improved, which can effectively extend the service life of the catalyst in the synthesis reaction of triacetone amine. (3) After washing the polymerized resin microspheres with water, further acidification treatment is carried out, which is beneficial to increase the number of acidic sites on the material and further improve the conversion rate and selectivity in the triacetone amine synthesis reaction. (4) Compared with the reactor, the catalyst of the present invention has higher production efficiency when used in a fixed bed. Using a fixed bed device to replace the reactor for continuous production is beneficial to improving the production efficiency of the industrial plant in the process of synthesizing triacetone amine, simplifying personnel operation, reducing the generation of wastewater and waste acid, and better meeting the needs of environmental protection. Detailed Implementation

[0024] The present invention will be further described in detail below with reference to specific embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0025] Example 1 A catalyst comprising a styrene-divinylbenzene copolymer backbone, an acetylacetone metal salt crosslinked to the styrene-divinylbenzene copolymer backbone by chemical bonds, and acidic sites supported on the styrene-divinylbenzene copolymer backbone.

[0026] The method for preparing the catalyst includes the following steps: Step 1: Put 6.24g styrene, 2.06g divinylbenzene, 15g n-heptane, and 0.134g AIBN into a reaction flask and stir until homogeneous; Step 2: Dissolve 1.76g of ferric acetylacetone in 20mL of ethyl acetate. After complete dissolution, add the solution to the reaction flask and stir it evenly with the solution obtained in Step 1. Step 3: Add the mixed solution obtained in Step 2 to 120 mL of a 2% (w / w) polyvinyl alcohol solution containing 0.003 g methylene blue, and stir at 100 °C for 12 hours. Step 4: After cooling to room temperature, remove the resin beads and wash them three times with 10 times the volume of deionized water, ensuring that the pH of the last washing solution is 7. Then place them in the reaction vessel, add 50 mL of 30% sulfuric acid solution, and stir and heat at 120°C for 24 hours. Step 5: Wash the obtained sample 8 times with deionized water, ensuring the pH of the last wash solution is 7, and then wash it 3 times with ethanol; dry to obtain the desired catalyst; the obtained catalyst is numbered CAT-1.

[0027] Example 2 A catalyst comprising a styrene-divinylbenzene copolymer backbone, an acetylacetone metal salt crosslinked to the styrene-divinylbenzene copolymer backbone by chemical bonds, and acidic sites supported on the styrene-divinylbenzene copolymer backbone.

[0028] The method for preparing the catalyst includes the following steps: Step 1: Put 7.32g of p-fluorostyrene, 2.06g of divinylbenzene, 15g of n-heptane, and 0.134g of AIBN into a reaction flask and stir until homogeneous; Step 2: Dissolve 1.76g of ferric acetylacetone in 20mL of ethyl acetate. After complete dissolution, add the solution to the reaction flask and stir it evenly with the solution obtained in Step 1. Step 3: Add the mixed solution obtained in Step 2 to 120 mL of a 2% (w / w) polyvinyl alcohol solution containing 0.003 g methylene blue, and stir at 100 °C for 12 hours. Step 4: After cooling to room temperature, remove the resin beads and wash them three times with 10 times the volume of deionized water, ensuring that the pH of the last washing solution is 7. Then place them in the reaction vessel, add 50 mL of 30% sulfuric acid solution, and stir and heat at 120°C for 24 hours. Step 5: Wash the obtained sample 8 times with deionized water, ensuring the pH of the last wash solution is 7, and then wash it 3 times with ethanol; dry to obtain the desired catalyst; the obtained catalyst is numbered CAT-2.

[0029] Example 3 The preparation steps of Example 3 are the same as those of Example 2, except that 7.32g of p-fluorostyrene in step (1) is replaced with 8.30g of p-chlorostyrene; the resulting catalyst is numbered CAT-3.

[0030] Example 4 The preparation steps of Example 4 are the same as those of Example 2, except that 7.32g of p-fluorostyrene in step (1) is replaced with 13.80g of p-iodine styrene; the resulting catalyst is numbered CAT-4.

[0031] Example 5 The preparation steps of Example 5 are the same as those of Example 2, except that 1.76g of iron acetylacetone in step (2) is replaced with 1.30g of copper acetylacetone; the resulting catalyst is numbered CAT-5.

[0032] Example 6 The preparation steps of Example 6 are the same as those of Example 2, except that 1.76g of iron acetylacetone in step (2) is replaced with 1.28g of nickel acetylacetone; the resulting catalyst is numbered CAT-6.

[0033] Example 7 The preparation steps of Example 7 are the same as those of Example 2, except that the sulfuric acid solution in step (4) is replaced with p-chlorobenzenesulfonic acid solution; the resulting catalyst is numbered CAT-7.

[0034] Example 8 The preparation steps of Example 8 are the same as those of Example 2, except that the sulfuric acid solution in step (4) is replaced with chlorosulfonic acid solution; the resulting catalyst is numbered CAT-8.

[0035] Comparative Example 1 A method for preparing a catalyst includes the following steps: Step 1: Put 6.24g styrene, 2.06g divinylbenzene, 15g n-heptane, and 0.134g AIBN into a reaction flask and stir until homogeneous; Step 2: Add the mixed solution obtained in Step 1 to 120 mL of a 2% (w / w) polyvinyl alcohol solution containing 0.003 g methylene blue, and stir at 100 °C for 12 hours. Step 3: After cooling to room temperature, remove the resin beads and wash them 8 times with 10 times the volume of deionized water, ensuring that the pH of the last wash solution is 7. Then wash them 3 times with ethanol. Dry them. The resulting catalyst is designated CAT-9.

[0036] Comparative Example 2 A method for preparing a catalyst includes the following steps: Step 1: Put 6.24g styrene, 2.06g divinylbenzene, 15g n-heptane, and 0.134g AIBN into a reaction flask and stir until homogeneous; Step 2: Dissolve 1.76g of ferric acetylacetone in 20mL of ethyl acetate. After complete dissolution, add the solution to the reaction flask and stir it evenly with the solution obtained in Step 1. Step 3: Add the mixed solution obtained in Step 2 to 120 mL of a 2% (w / w) polyvinyl alcohol solution containing 0.003 g methylene blue, and stir at 100 °C for 12 hours. Step 4: After cooling to room temperature, remove the resin beads and wash them 8 times with 10 times their volume of deionized water, ensuring that the pH of the last wash solution is 7. Then wash them 3 times with ethanol. Dry them. The resulting catalyst is designated CAT-10.

[0037] Comparative Example 3 A method for preparing a catalyst includes the following steps: Step 1: Put 6.24g styrene, 2.06g divinylbenzene, 15g n-heptane, and 0.134g AIBN into a reaction flask and stir until homogeneous; Step 2: Add the above mixed solution to 120 mL of a 2% (w / w) polyvinyl alcohol solution containing 0.003 g methylene blue, and stir at 100 °C for 12 hours; Step 3: After cooling to room temperature, remove the resin beads and wash them three times with 10 times the volume of deionized water, ensuring that the pH of the last washing solution is 7. Then place them in the reaction vessel, add 50 mL of 30% sulfuric acid solution, and stir and heat at 120°C for 24 hours. Step 4: Wash the obtained sample 8 times with deionized water, ensuring the pH of the last wash solution is 7, and then wash it 3 times with ethanol; dry to obtain the desired catalyst; the obtained catalyst is numbered CAT-11.

[0038] The comparison between Comparative Example 1 and Comparative Example 2 shows the effect of acetylacetone metal salt modification on catalyst activity and selectivity; the addition of iron acetylacetone in Comparative Example 2 introduced metal sites into the catalyst, increased the number of catalytic active sites, and thus improved the catalyst conversion and selectivity. Comparing Comparative Example 1 and Comparative Example 3, we can see the effect of acid treatment on catalyst activity and selectivity. In Comparative Example 3, the addition of sulfuric acid aqueous solution introduced acid sites into the catalyst, increasing the number of catalytic active sites, thereby improving the catalyst's conversion rate and selectivity. Comparing Comparative Examples 1, 2, and 3 with Example 1, it can be seen that the combined effect of acetylacetone metal salt and acid treatment on catalyst activity and selectivity is evident. In Example 1, both metal sites and acid sites were introduced, and their combined effect improved the catalyst's conversion rate and selectivity. The comparison of Examples 2, 3, and 4 shows the effect of different electron-withdrawing groups of styrene derivatives on catalyst activity and selectivity. These examples used styrene derivatives with fluorine, chlorine, and iodine groups. Among these groups, fluorine exhibits the strongest electron-withdrawing effect, thereby maximizing the conversion rate and selectivity of the catalyst. The comparison of Examples 2, 5, and 6 shows the effect of different acetylacetone metal salt modifications on catalyst activity and selectivity. These examples used iron acetylacetone, copper acetylacetone, and nickel acetylacetone, among which iron has relatively stronger metal acidity, thereby maximizing the catalyst conversion and selectivity. The comparison of Examples 2, 7, and 8 shows the effect of different acid solutions used in the acid treatment step on the catalyst activity and selectivity. In these examples, sulfuric acid, p-chlorobenzenesulfonic acid, and aqueous chlorosulfonic acid solutions were used. Among them, sulfuric acid has a better affinity with the resin and is more likely to introduce acid sites onto the resin, thereby obtaining a catalyst with higher conversion rate and selectivity.

[0039] Example 9 A method for synthesizing triacetone amine using a fixed-bed reactor includes the following steps: (1) 40 mL of catalyst was loaded into the isothermal zone of a fixed-bed reactor equipped with a condenser. The fixed-bed reactor was heated to 55 °C under a flowing N2 atmosphere and maintained for 1 hour. (2) After shutting off N2, acetone and ammonia are introduced into the fixed-bed reactor at a molar ratio of 4:1, and the volume hourly space velocity of ammonia is 20 h⁻¹. -1 ; (3) The product was cooled to obtain crude triacetone amine, and then the crude product was subjected to qualitative and quantitative analysis by chromatography.

[0040] After the reaction reached equilibrium, samples were taken for analysis. The comparison data of acetone conversion and triacetone amine selectivity of catalysts CAT-1 to CAT-11 are shown in the table below:

[0041] Example 10 A method for synthesizing triacetone amine using a reaction vessel includes the following steps: 40 mL of catalyst and acetone were loaded into the reaction vessel. The gas inside the vessel was replaced five times with N2 atmosphere. The temperature of the reaction vessel reactor was then raised to 55°C. Shut down the N2 gas line, maintain the temperature inside the reactor, and gradually introduce a certain mass of ammonia gas to ensure that the molar ratio of acetone to ammonia gas is 4:1. The reaction temperature was maintained, the stirring was turned on, and the reaction was carried out for 8 hours. After cooling, crude triacetoneamine was obtained, and then the crude product was qualitatively and quantitatively analyzed by chromatography.

[0042] After the reaction reached equilibrium, samples were taken for analysis. The comparison data of acetone conversion and triacetone amine selectivity of catalysts CAT-1 to CAT-11 are shown in the table below:

[0043] The above description is only a preferred embodiment of the present invention. It should be noted that, for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A catalyst, characterized in that, It includes a styrene-divinylbenzene copolymer backbone, an acetylacetone metal salt crosslinked to the styrene-divinylbenzene copolymer backbone by chemical bonds, and acidic sites supported on the styrene-divinylbenzene copolymer backbone.

2. The catalyst according to claim 1, characterized in that, The acetylacetone metal salt is iron acetylacetone, copper acetylacetone, nickel acetylacetone, cobalt acetylacetone, or manganese acetylacetone, and the mass of the acetylacetone metal salt is 1% to 10% of the mass of the catalyst.

3. The method for preparing the catalyst according to claim 1 or 2, characterized in that, Includes the following steps: Step s1: Styrene or styrene derivatives are mixed with divinylbenzene, a porogen, an initiator, an acetylacetone metal salt, and a solvent to obtain an oil phase system. The dispersant and polymerization inhibitor solutions were mixed evenly to obtain an aqueous phase system; Step s2: The oil phase system is added to the aqueous phase system to disperse the oil phase system into uniform droplets. After the reaction is complete, the resin microspheres are obtained by filtration. Step s3: Wash the resin beads and then add an acid solution for acidification to obtain acidified resin beads; Step s4: Wash and dry the acidified resin pellets to obtain the catalyst.

4. The preparation method according to claim 3, characterized in that, In step s1, styrene or styrene derivatives, divinylbenzene, pore-forming agent and initiator are first stirred evenly to obtain an oil phase; then, acetylacetone metal salt is dissolved in a solvent and mixed evenly with the oil phase to obtain an oil phase system. The molar ratio of styrene or styrene derivatives to divinylbenzene is 1:1 to 8:1; The styrene derivative is styrene with an electron-withdrawing group, wherein the electron-withdrawing group is a halogen, nitro, or carbonyl group, and the halogen is fluorine, chlorine, bromine, or iodine. The pore-forming agent is toluene, n-heptane, or a mixture thereof; The initiator is benzoyl peroxide or azobisisobutyronitrile; The mass fraction of the metal salt of acetylacetone in the solvent is 5-10%; The solvent is ethyl acetate, chloroform, dichloromethane, or tetrahydrofuran; The dispersant is a 1-10% (w / w) polyvinyl alcohol or gelatin solution; The polymerization inhibitor is one of methylene blue and p-tert-butylcatechol.

5. The preparation method according to claim 3, characterized in that, In step s2, after the oil phase system is added to the aqueous phase system, it is kept at 60~100℃ and stirred for 4~12 hours, and then filtered to obtain resin microspheres.

6. The preparation method according to claim 3, characterized in that, In step s3, the washing process uses hot water at 50~80℃. After washing the resin beads, add them to the acid solution and stir and heat at 60~120℃ for 12~24 hours to complete the acidification. The acid solution is one or more of sulfuric acid, benzenesulfonic acid, p-chlorobenzenesulfonic acid, and chlorosulfonic acid aqueous solution, the mass fraction of the acid solution is 10-50%, and the volume of the acid solution is 1-10 times the volume of the resin beads.

7. The preparation method according to claim 3, characterized in that, In step s4, during washing, deionized water is first used to wash until the pH of the washing solution is 5-8, and then ethanol is used to wash.

8. The application of the catalyst as described in claim 1 in the synthesis of triacetone amine.

9. A method for synthesizing triacetone amine in a fixed bed, characterized in that, Includes the following steps: Step 1: The catalyst as described in claim 1 is loaded into the isothermal zone of an atmospheric pressure fixed-bed reactor equipped with a condenser. Under a flowing N2 atmosphere, the fixed-bed reactor is heated to 40~120°C and maintained for 1~3 hours. Step 2: After shutting off N2, introduce acetone and ammonia into the fixed-bed reactor at a molar ratio of 3-12:1, with a volume hourly space velocity (VHSV) of 10-100 h⁻¹. -1 ; Step 3: The product is cooled to obtain crude triacetone amine.

10. A method for synthesizing triacetone amine in a reaction vessel, characterized in that, Includes the following steps: Step 1: The catalyst and acetone as described in claim 1 are loaded into the reaction vessel, the gas inside the vessel is replaced with N2 atmosphere, and the temperature of the reaction vessel reactor is raised to 40~120°C. Step 2: Close the N2 gas line, maintain the temperature inside the reactor, and introduce ammonia gas so that the molar ratio of acetone to ammonia gas is 3~12:1; Step 3: Maintain the reaction temperature, turn on the stirrer, and react for 8-16 hours; Step 4: After stopping the reaction, replace the residual ammonia in the reactor with nitrogen. After natural cooling, crude triacetone amine is obtained in the reactor.

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