A catalyst for the synthesis of triacetone amine in a fixed bed and a method for its preparation
A solid acid catalyst was prepared by grafting sulfonic acid groups onto a SiO2 support, which solved the problem of low catalyst activity in the fixed-bed production of triacetone amine, achieving efficient and stable catalytic effects and reducing production costs.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- 宿迁联盛科技股份有限公司
- Filing Date
- 2024-04-17
- Publication Date
- 2026-07-24
AI Technical Summary
In the existing technology, the fixed-bed production of triacetone amine has problems such as low catalyst activity, complex preparation methods, high cost, and unsuitability for industrial application.
Solid acid catalysts were prepared by grafting. Sulfonic acid groups were grafted in situ onto a SiO2 support, using 3-mercaptopropylmethyldimethoxysilane as an intermediate, and calcined under a N2 atmosphere to form a catalyst with high activity and stability, suitable for fixed-bed reaction processes.
This improved the yield of triacetone amine and the stability of the catalyst, enabling efficient and continuous production in a fixed-bed reaction and reducing production costs.
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Figure CN118356970B_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of catalyst technology, specifically relating to a catalyst for the fixed-bed synthesis of triacetone amine and its preparation method. Background Technology
[0002] With the rapid development of my country's fine chemicals industry, hindered amine light stabilizers have also seen explosive growth. 2,2,6,6-Tetramethyl-4-piperidinone (triacetone amine, TAA) is the initial raw material for the synthesis of many hindered amine light stabilizers (such as Tinuvin 622, Tinuvin 770, and Chimassorb 944), and it is also a derivative parent material for the synthesis of many intermediates in the fine chemical industry (such as 2,2,6,6-tetramethyl-4-piperidinol, 2,2,6,6-tetramethyl-4-piperidinamine, and N,N-bis(2,2,6,6-tetramethyl-4-piperidinyl)-1,6-hexanediamine). Developing catalysts with high safety and stability for use in new continuous production processes can effectively improve the yield and quality of triacetone amine, and has significant industrial application value.
[0003] Traditional TAA production processes employ batch reactor-type production, using acetone and ammonia as raw materials, with ammonium nitrate as a catalyst. This process involves intermittent production according to a fixed formula, resulting in low efficiency, large space requirements, and high labor costs. Fixed-bed production, on the other hand, enables continuous TAA production, effectively improving efficiency, saving space, and reducing costs. While batch production uses ammonium nitrate as a catalyst, it poses safety risks and incurs high safety costs. Fixed-bed production requires a highly active and stable catalyst. CN 107987013A discloses a method for preparing 2,2,6,6-tetramethyl-4-piperidinone, using a sulfonic acid-modified UIO-66 catalyst. However, this catalyst preparation method is complex, and the solvent used is highly toxic, limiting its use to small-scale experiments and lacking industrial application value. The synthesis of triacetone amine in this patent still employs a high-pressure reactor-type batch production method, which, while improving the yield, still fails to solve the problems inherent in batch production. CN 114797896A discloses a method for preparing and using a catalyst for the fixed-bed synthesis of 2,2,6,6-tetramethyl-4-piperidinone. The catalyst uses an acidic resin as a precursor, which is treated, sulfonated, and then impregnated with metal ions. This catalyst preparation method is complex and involves a long process flow. The preparation requires NaOH and HCl solutions, places high demands on equipment, consumes a lot of energy, and has high production costs, making it unsuitable for industrial production. Furthermore, the catalyst has relatively low activity.
[0004] The purpose of this invention is to provide a solid acid catalyst for the synthesis of triacetone amine and its preparation method. This novel solid acid catalyst addresses the problem of low yield in the fixed-bed synthesis of 2,2,6,6-tetramethyl-4-piperidinone, and further solves the problems of low production efficiency, large space requirements, and high labor costs associated with batch production. Summary of the Invention
[0005] To address the aforementioned problems, this invention discloses a solid acid catalyst for the synthesis of triacetone amine and its preparation method. This catalyst can efficiently catalyze the synthesis of triacetone amine, achieving a high yield conversion of triacetone amine, and can be used stably and for a long time in a fixed-bed reaction process.
[0006] To achieve the above objectives, the technical solution of the present invention is as follows:
[0007] A method for preparing a solid acid catalyst for the synthesis of triacetone amine, characterized by comprising the following steps:
[0008] (1) P123 and water are mixed and stirred until dissolved. Hydrochloric acid solution is added and stirred and heated to 40-80℃ to obtain solution A.
[0009] (2) Keeping the temperature of step (1), add tetraethyl silicate dropwise to solution A and continue stirring for 2 hours; then add 3-mercaptopropylmethyldimethoxysilane dropwise and stir for 1-4 hours; then add 30 wt.% H2O2 and stir overnight to obtain mixture B;
[0010] (3) Filter mixture B to obtain filtrate C and filter cake D;
[0011] (4) After mixing filtrate C with activated carbon, stir for 2 hours, filter to obtain filtrate, mix filtrate with filter cake D, stir and transfer to hydrothermal reactor, and after aging, filtration, alcohol washing, acidification, water washing, drying, grinding and calcination, obtain powder E;
[0012] (5) After the calcined powder E is mixed evenly with the auxiliary materials, it is extruded into strips by an extruder. After the formed catalyst is placed at room temperature, it is dried and broken into strips to obtain a catalyst with a length of 3-5 mm.
[0013] Further, in step (1), the concentration of hydrochloric acid is 1 to 12.5 mol / L; the mass ratio of P123, water and hydrochloric acid is 5 to 40:490:2 to 20.
[0014] Further, in step (2), the mass ratio of tetraethyl silicate, 3-mercaptopropylmethyldimethoxysilane, 30 wt.% H2O2 to water in step (1) is 4-20:1-5:24-48:196.
[0015] Furthermore, in step (4), the aging temperature is 90-120℃ and the aging time is 12-48h.
[0016] Furthermore, in step (4), the calcination atmosphere is flowing N2, the calcination temperature is 300-500℃, and the calcination time is 4-6h.
[0017] Furthermore, in step (4), the alcohol used for alcohol washing is anhydrous ethanol; the acid used for acidification is 1 mol / L dilute hydrochloric acid.
[0018] Further, in step (5), the excipients are water, graphite, glycerin, and citric acid; the mass ratio of powder E, water, graphite, glycerin, and citric acid is 2000:200:80:15:2:1.
[0019] The present invention also provides a solid acid catalyst for the synthesis of triacetone amine prepared by the preparation method described above.
[0020] The present invention also provides the application of the solid acid catalyst described above for the synthesis of triacetone amine in a fixed-bed synthesis reaction of triacetone amine.
[0021] The application method is as follows:
[0022] (1) The catalyst is loaded into the fixed bed reactor, N2 gas is introduced to remove the oxygen in the reactor system, the reactor is heated to raise the temperature to 30-50°C, and the reactor temperature is maintained for 12 hours to allow the catalyst to be fully preheated.
[0023] (2) Acetone and ammonia are fed into the fixed-bed reactor in two separate streams at a volume ratio of 1:3 to 25. The volume hourly space velocity (VHSV) of ammonia is 2 to 15 h⁻¹. -1 ;
[0024] (3) The product after the reaction is cooled to obtain crude triacetone amine. The content of triacetone amine is measured every 4 hours.
[0025] The synthetic route for the reaction in this invention is as follows:
[0026]
[0027] The beneficial effects of this invention are as follows:
[0028] (1) Solid acid catalysts are prepared by grafting. Sulfonic acid group substances are grafted in situ during the synthesis of SiO2 support. The sulfonic acid group is firmly anchored and not easy to fall off, thus exhibiting high catalytic stability.
[0029] (2) 3-mercaptopropylmethyldimethoxysilane is used as an intermediate for sulfonic acid groups. Sulfonic acid groups can be obtained by oxidation. Using this substance as an intermediate for sulfonic acid groups can effectively increase the number of sulfonic acid groups exposed in the space, which can further enhance the activity of the catalyst, thereby increasing the conversion rate of acetone and the yield of triacetone amine.
[0030] (3) After the catalyst is synthesized, calcination under N2 atmosphere can effectively eliminate organic impurities and remove H from the grafted 3-mercaptopropylmethyldimethoxysilane, effectively increasing the number of sulfonic acid active sites, thereby improving the activity of the catalyst; through calcination, SiO2 can be further crystallized, thereby improving the strength and stability of the catalyst.
[0031] (4) After the catalyst is extruded, it can still maintain high activity and stability, and the catalytic effect of fixed bed synthesis of triacetone amine is better. Attached Figure Description
[0032] Figure 1 The N2 isothermal adsorption-desorption curves of the catalyst prepared in Example 1 are shown in the inset, with the pore size distribution diagram shown in the inset.
[0033] Figure 2 Statistical graphs of triacetone conversion, triacetone amine selectivity, and yield of catalysts CAT-1 to CAT-14 for 7 days of catalytic reaction;
[0034] Figure 3 This is a SEM image of the catalyst prepared in Example 1. Detailed Implementation
[0035] The present invention will be further illustrated below with reference to the accompanying drawings and specific embodiments. It should be understood that the following specific embodiments are for illustrative purposes only and are not intended to limit the scope of the invention.
[0036] The manufacturers and models of the compounds used in the following examples are shown below; other chemical reagents used, unless otherwise specified, were obtained through conventional commercial channels.
[0037]
[0038]
[0039] Example 1
[0040] The catalyst preparation steps for the fixed-bed synthesis of triacetone amine are as follows:
[0041] (1) Weigh 40g of P123 and 980g of water, stir until dissolved, add 18g of 12.5mol / L hydrochloric acid, stir and heat to 40℃ to obtain solution A.
[0042] (2) Add 80g of tetraethyl silicate to solution A and stir at 40℃ for 2h; continue to add 25g of 3-mercaptopropylmethyldimethoxysilane and stir for 2h; pour 180g of 30wt.% H2O2 into the solution and stir overnight to obtain mixture B.
[0043] (3) Filter mixture B to obtain filtrate C and filter cake D.
[0044] (4) After mixing filtrate C with 20g activated carbon, stir for 2h, filter to obtain filtrate, measure 300ml of filtrate and mix with filter cake D, stir and transfer to 500ml hydrothermal reactor, age at 90℃ for 24h, and obtain powder E after filtration, alcohol washing, acidification, water washing, drying and grinding.
[0045] (5) Powder E was calcined for 5 hours in a flowing N2 atmosphere at 300-600℃.
[0046] (6) Powder E is mixed with excipients water, graphite, glycerol and citric acid in a mass ratio of 2000:200:80:15:2:1 and then extruded into strips by an extruder. After the shaped catalyst is placed at room temperature, it is dried and broken into strips to obtain a catalyst with a length of 3 to 5 mm, which is denoted as CAT-1.
[0047] The N2 isotherm adsorption-desorption curves and pore size distribution diagrams of the prepared catalyst are shown below. Figure 1 As shown, the prepared catalyst has a high specific surface area (specific surface area of 375 m²). 2 The catalyst has a mesoporous structure (pore size mainly distributed in 9-34 nm), allowing acetone and NH3 to pass smoothly through the catalyst channels, thereby effectively improving the conversion rate of acetone.
[0048] Example 2
[0049] The catalyst preparation steps for the fixed-bed synthesis of triacetone amine are as follows:
[0050] Other conditions are the same as in Example 1, except that the amount of hydrochloric acid added in step (1) is changed: the amount of hydrochloric acid added is 36g, and the resulting catalyst is denoted as CAT-2.
[0051] Example 3
[0052] The catalyst preparation steps for the fixed-bed synthesis of triacetone amine are as follows:
[0053] Other conditions are the same as in Example 1, except that the concentration of hydrochloric acid in step (1) is changed to 5 mol / L, and the resulting catalyst is denoted as CAT-3.
[0054] Example 4
[0055] The catalyst preparation steps for the fixed-bed synthesis of triacetone amine are as follows:
[0056] Other conditions are the same as in Example 1, except that the temperature during stirring in step (1) is changed to 60°C, and the resulting catalyst is denoted as CAT-5.
[0057] Example 5
[0058] The catalyst preparation steps for the fixed-bed synthesis of triacetone amine are as follows:
[0059] Other conditions are the same as in Example 1, except that the amount of tetraethyl silicate added in step (2) is changed: the amount added is 60g, and the resulting catalyst is denoted as CAT-4.
[0060] Example 6
[0061] The catalyst preparation steps for the fixed-bed synthesis of triacetone amine are as follows:
[0062] Other conditions are the same as in Example 1, except that the amount of 3-mercaptopropyldimethoxysilane added in step (2) is changed to 10g, and the resulting catalyst is denoted as CAT-6.
[0063] Example 7
[0064] The catalyst preparation steps for the fixed-bed synthesis of triacetone amine are as follows:
[0065] Other conditions are the same as in Example 1, except that the amount of 30wt.% H2O2 added in step (2) is changed to 220g, and the resulting catalyst is denoted as CAT-7.
[0066] Example 8
[0067] The catalyst preparation steps for the fixed-bed synthesis of triacetone amine are as follows:
[0068] Other conditions are the same as in Example 1, except that the aging temperature in step (4) is changed to 120°C, and the resulting catalyst is denoted as CAT-8.
[0069] Example 9
[0070] The catalyst preparation steps for the fixed-bed synthesis of triacetone amine are as follows:
[0071] Other conditions are the same as in Example 1, except that the aging time in step (4) is changed to 12h, and the resulting catalyst is denoted as CAT-9.
[0072] Example 10
[0073] The catalyst preparation steps for the fixed-bed synthesis of triacetone amine are as follows:
[0074] Other conditions are the same as in Example 1, except that the calcination temperature in step (5) is changed to 300°C, and the resulting catalyst is denoted as CAT-10.
[0075] Example 11
[0076] The catalyst preparation steps for the fixed-bed synthesis of triacetone amine are as follows:
[0077] Other conditions are the same as in Example 1, except that the calcination time in step (5) is changed to 4 hours, and the resulting catalyst is denoted as CAT-11.
[0078] Comparative Example 1
[0079] The purpose is to compare with Example 1 to illustrate the effect of the activated carbon treatment step on catalytic activity.
[0080] The catalyst preparation steps for the fixed-bed synthesis of triacetone amine are as follows:
[0081] (1) Weigh 40g of P123 and 980g of water, stir until dissolved, add 18g of 12.5mol / L hydrochloric acid, stir and heat to 40℃ to obtain solution A.
[0082] (2) Add 80g of tetraethyl silicate to solution A and stir at 40℃ for 2h; continue to add 25g of 3-mercaptopropylmethyldimethoxysilane and stir for 2h; pour 180g of 30wt.% H2O2 into the solution and stir overnight. After filtration, alcohol washing, acidification, water washing, drying and grinding, powder E is obtained.
[0083] (3) Powder E was calcined for 5 hours in a flowing N2 atmosphere at 300-600℃.
[0084] (4) Powder E is mixed with auxiliary materials water, graphite, glycerol and citric acid in a mass ratio of 2000:200:80:15:2:1 and then extruded into strips by an extruder. After the shaped catalyst is placed at room temperature, it is dried and broken into strips to obtain a catalyst with a length of 3 to 5 mm, which is denoted as CAT-12.
[0085] Comparative Example 2
[0086] The purpose is to compare with Example 1 to illustrate the effect of the hydrothermal reactor aging process on catalytic activity.
[0087] The catalyst preparation steps for the fixed-bed synthesis of triacetone amine are as follows:
[0088] (1) Weigh 40g of P123 and 980g of water, stir until dissolved, add 18g of 12.5mol / L hydrochloric acid, stir and heat to 40℃ to obtain solution A.
[0089] (2) Add 80g of tetraethyl silicate to solution A and stir at 40℃ for 2h; continue to add 25g of 3-mercaptopropylmethyldimethoxysilane and stir for 2h; pour 180g of 30wt.% H2O2 into the solution and stir overnight to obtain mixture B.
[0090] (3) Filter mixture B to obtain filtrate C and filter cake D.
[0091] (4) After mixing filtrate C with 20g activated carbon and stirring for 2h, filter to obtain filtrate. Measure 300ml of filtrate and mix with filter cake D. Stir at 90℃ for 24h. After filtration, alcohol washing, acidification, water washing, drying and grinding, powder E is obtained.
[0092] (5) Powder E was calcined for 5 hours in a flowing N2 atmosphere at 300-600℃.
[0093] (6) Powder E is mixed with auxiliary materials water, graphite, glycerol and citric acid in a mass ratio of 2000:200:80:15:2:1 and then extruded into strips by an extruder. After the shaped catalyst is placed at room temperature, it is dried and broken into strips to obtain a catalyst with a length of 3 to 5 mm, which is denoted as CAT-13.
[0094] Comparative Example 3
[0095] The purpose is to compare with Example 1 to illustrate the effect of flowing N2 atmosphere treatment on catalytic activity.
[0096] The catalyst preparation steps for the fixed-bed synthesis of triacetone amine are as follows:
[0097] (1) Weigh 40g of P123 and 980g of water, stir until dissolved, add 18g of 12.5mol / L hydrochloric acid, stir and heat to 40℃ to obtain solution A.
[0098] (2) Add 80g of tetraethyl silicate to solution A and stir at 40℃ for 2h; continue to add 25g of 3-mercaptopropylmethyldimethoxysilane and stir for 2h; pour 180g of 30wt.% H2O2 into the solution and stir overnight to obtain mixture B.
[0099] (3) Filter mixture B to obtain filtrate C and filter cake D.
[0100] (4) After mixing filtrate C with 20g activated carbon and stirring for 2h, filter to obtain filtrate. Measure 300ml of filtrate and mix with filter cake D. Stir at 90℃ for 24h. After filtration, alcohol washing, acidification, water washing, drying and grinding, powder E is obtained.
[0101] (5) Powder E was calcined at 300-600℃ under a static N2 atmosphere for 5 hours.
[0102] (6) Powder E is mixed with auxiliary materials water, graphite, glycerol and citric acid in a mass ratio of 2000:200:80:15:2:1 and then extruded into strips by an extruder. After the shaped catalyst is placed at room temperature, it is dried and broken into strips to obtain a catalyst with a length of 3 to 5 mm, which is denoted as CAT-14.
[0103] The evaluation process and conditions for catalysts are as follows:
[0104] (1) Pack 150 ml of catalyst into a fixed bed reactor, introduce N2 gas to remove oxygen from the reactor system, heat the reactor to raise the temperature to 52°C, and maintain the reactor temperature for 12 h to fully preheat the catalyst.
[0105] (2) Acetone and ammonia are fed into the fixed-bed reactor simultaneously in two separate streams at a volume ratio of 1:23. The volume hourly space velocity (VHSV) of the ammonia is 9 h⁻¹. 1 .
[0106] (3) The product after the reaction is cooled to obtain crude triacetone amine. The content of triacetone amine is measured every 4 hours.
[0107] The reaction was carried out using CAT-1 to CAT-14 as catalysts, and each catalyst was evaluated for 7 days. The comparison data of acetone conversion, average selectivity and yield of triacetone amine are shown in Table 1 below:
[0108] Table 1
[0109] Catalyst number Acetone conversion rate (%) Triacetone amine selectivity (%) Triacetone amine yield (%) CAT-1 58.2 68.4 39.8 CAT-2 56.3 65.4 36.8 CAT-3 35.6 46.3 16.5 CAT-4 49.7 60.0 29.8 CAT-5 46.5 59.1 27.5 CAT-6 21.8 22.0 4.8 CAT-7 60.5 67.1 40.6 CAT-8 48.6 52.9 25.7 CAT-9 22.5 24.0 5.4 CAT-10 39.4 52.8 20.8 CAT-11 56.7 63.0 35.7 CAT-12 26.7 26.6 7.1 CAT-13 16.2 14.2 2.3 CAT-14 7.6 6.6 0.5
[0110] The statistical graphs of triacetone conversion, triacetone amine selectivity, and yield of catalysts CAT-1 to CAT-14 after 7 days are shown below. Figure 2 As shown, CAT-1 exhibits the highest acetone conversion rate and triacetone amine yield, and the catalyst also demonstrates high catalytic stability. After changing the reaction conditions, the catalytic activities of the prepared catalysts CAT2 to CAT-11 all decreased to some extent. When the preparation steps were changed, the activities of the prepared catalysts CAT-12 to CAT-14 decreased significantly, indicating that the comparative steps had a greater impact on the catalyst activity.
[0111] Figure 3 The image shows a SEM image of the catalyst CAT-1 prepared in the example. The catalyst is spherical, and the large spheres are relatively uniform in size, which gives the catalyst a larger surface area, thus helping to improve the catalyst's activity.
[0112] It should be noted that the above content merely illustrates the technical concept of the present invention and should not be construed as limiting the scope of protection of the present invention. For those skilled in the art, various improvements and modifications can be made without departing from the principle of the present invention, and all such improvements and modifications fall within the scope of protection of the claims of the present invention.
Claims
1. A method for preparing a solid acid catalyst for the synthesis of triacetone amine, characterized in that, Includes the following steps: (1) P123 and water are mixed and stirred until dissolved, hydrochloric acid solution is added, and the mixture is stirred and heated to 40~80℃ to obtain solution A; (2) Add tetraethyl silicate to solution A and continue stirring for 2 hours; then add 3-mercaptopropylmethyldimethoxysilane and stir for 1-4 hours; then add 30 wt.% H2O2 and stir overnight to obtain mixture B; (3) Filter mixture B to obtain filtrate C and filter cake D; (4) After mixing filtrate C with activated carbon, stir for 2 hours, filter to obtain filtrate, mix filtrate with filter cake D, stir and transfer to hydrothermal reactor, after aging, filtration, alcohol washing, acidification, water washing, drying, grinding, and calcination under flowing N2 conditions to obtain powder E. (5) After the calcined powder E is mixed evenly with the auxiliary materials, it is extruded into strips by an extruder. After the shaped catalyst is placed at room temperature, it is dried and broken into strips to obtain a catalyst with a length of 3~5mm.
2. The method for preparing a solid acid catalyst for the synthesis of triacetone amine according to claim 1, characterized in that, In step (1), the concentration of hydrochloric acid is 1~12.5 mol / L; the mass ratio of P123, water and hydrochloric acid is 5~40:490:2~20.
3. The method for preparing a solid acid catalyst for the synthesis of triacetone amine according to claim 1, characterized in that, In step (2), the mass ratio of tetraethyl silicate, 3-mercaptopropylmethyldimethoxysilane, 30wt.% H2O2 to water in step (1) is 4~20:1~5:24~48:
196.
4. The method for preparing a solid acid catalyst for the synthesis of triacetone amine according to claim 1, characterized in that, In step (4), the aging temperature is 90~120℃ and the aging time is 12~48h.
5. The method for preparing a solid acid catalyst for the synthesis of triacetone amine according to claim 1, characterized in that, In step (4), the calcination atmosphere is flowing N2, the calcination temperature is 300~500℃, and the calcination time is 4~6h.
6. The method for preparing a solid acid catalyst for the synthesis of triacetone amine according to claim 1, characterized in that, In step (4), the alcohol used for alcohol washing is anhydrous ethanol; the acid used for acidification is 1 mol / L dilute hydrochloric acid.
7. The method for preparing a solid acid catalyst for the synthesis of triacetone amine according to claim 1, characterized in that, In step (5), the excipients are water, graphite, glycerin, and citric acid; the mass ratio of powder E, water, graphite, glycerin, and citric acid is 2000:200:80:15:2:
1.
8. A solid acid catalyst for the synthesis of triacetone amine prepared by the preparation method according to any one of claims 1-7.
9. The application of the solid acid catalyst for the synthesis of triacetone amine as described in claim 8 in the fixed-bed synthesis of triacetone amine.