Composite porous solid acid catalyst and its application in catalyzing generation of triacetone amine from acetone and ammonia

Abstract

The application belongs to the technical field of synthesizing triacetone amine, and discloses a composite porous solid acid catalyst and application thereof in catalyzing synthesis of triacetone amine from ketone and ammonia. The application uniformly mechanically mixes an acid nano-zeolite molecular sieve with a pore size structure of micro-meso-macropore structure and an acid ion exchange resin with a sulfonic acid group, shapes, and dries to obtain a composite porous solid acid catalyst. The composite porous solid acid catalyst is used in a fixed bed reactor to continuously synthesize triacetone amine from ketone and ammonia at low temperature and normal pressure, the product has high yield, the post-reaction treatment is simple, pollution-free, and conducive to large-scale continuous production.

Description

Technical Field

[0001] This invention relates to the preparation of a composite porous solid acid catalyst and its application in the efficient catalysis of the reaction of acetone and ammonia to produce triacetone amine. Background Technology

[0002] Triacetone amine (TAA) is an important intermediate, chemically named 2,2,6,6-tetramethylpiperidinone. It is the sole parent compound for the synthesis of hindered light-stabilized piperidine derivatives. The 2,2,6,6-tetramethyl-r-piperidinol obtained by its reduction is a crucial raw material for the preparation of novel, high-efficiency light stabilizers 770GW540 and HALS. It is also an important intermediate for the preparation of 4-substituted thio-2,2,6,6-tetramethylpiperidinamine aminooxy radical compounds. This compound has many applications in spin labeling / radiation techniques and in the inhibition of olefin polymerization. 2,2,6,6-4-tetramethylpiperidinone (hereinafter referred to as triacetone amine, TAA) is a basic raw material for the synthesis of hindered amine light stabilizers. These light stabilizers are currently the best-performing and fastest-developing class of light stabilizers. Triacetone amine, also called piperidinone, can be synthesized using two main methods: a two-step synthesis and a one-step synthesis. The two-step synthesis of triacetone amine mainly uses acetone or acetone and ammonia as raw materials, first synthesizing intermediates such as acetone-1, phorone, and diacetone alcohol, and then reacting them with ammonia or acetone to synthesize triacetone amine. The one-step method uses acetone and ammonia for condensation. The one-step method directly uses ammonia and acetone to react under the action of a catalyst. Compared with the two-step method, it avoids the synthesis and separation of intermediates, reduces reaction and separation steps, and lowers production costs, thus having significant advantages. One of the key technologies for the one-step synthesis of triacetone amine is the development of catalysts. In recent years, scholars from various countries have conducted extensive research on catalysts for the one-step synthesis of triacetone amine. For example, using calcium chloride as a catalyst (CN113620864A) results in a very slow reaction; using acidic ion exchange resin / Lewis acid as a catalyst (CN113999165A) for the two-step synthesis of triacetone amine requires separation steps in both steps, which is very cumbersome; using a single resin or molecular sieve (CN108383776A) results in low yields. CN102516158A describes a method for synthesizing triacetone amine in a fixed-bed reactor. This method uses a solid acid catalyst in a fixed-bed reactor, but the reaction temperature is between 100 and 280°C, which is relatively high. Furthermore, the reaction is not carried out at atmospheric pressure, making the reaction conditions harsh and difficult to industrialize. Additionally, the solvents mixed in with acetone, such as benzene, dioxane, and cyclohexane, are expensive and toxic. It is noteworthy that acetone has a boiling point of 56.5°C, while the boiling points of benzene and cyclohexane added to this raw material are around 80°C. Therefore, increasing the reaction temperature leads to a decrease in yield. Thus, synthesizing triacetone amine at lower temperatures is challenging. For example, CN106866503A describes a method for continuous synthesis of triacetone amine using a low-temperature liquid-phase fixed-bed reactor. Although the reaction temperature is controlled at 60-70°C, the yield of triacetone amine is only about 30%, which is low.

[0003] Given the current market demand, developing a continuous, low-cost process for producing tetramethylpiperidinol at normal pressure and low temperature is of significant research value. Summary of the Invention

[0004] To address the problems in the background technology, this invention uses acidic nano-zeolite molecular sieves and acidic resins with sulfonic acid groups as initial raw materials to prepare a composite catalyst, and realizes the continuous synthesis of triacetone amine from acetone and ammonia under low temperature and normal pressure in a continuous fixed-bed reactor.

[0005] To achieve the above-mentioned technical effects, the technical solution adopted by the present invention is as follows:

[0006] The preparation method of the composite porous solid acid catalyst is as follows: acidic nano-zeolite molecular sieves and acidic ion exchange resin with sulfonic acid groups are mechanically mixed evenly, shaped, and dried to obtain the composite porous solid acid catalyst.

[0007] As an improvement of this invention, the acidic nano-zeolite molecular sieve is one or a combination of two or more of the following: HMOR-NA molecular sieve, HBeta-NA molecular sieve, HZSM-5-NA molecular sieve, and HY-NA type molecular sieve with a micro-meso-macroporous structure, and is not limited to these types of molecular sieves. The acidic resin is one or a combination of two or more of the following: Supelco 06423amberlyst 15 hydrogen form resin, Supelco 216399amberlyst 15 hydrogen form resin, and Supelco 06428amberlite IRC120H hydrogen form resin, and is not limited to these types of acidic resins.

[0008] As a preferred option, the structural parameters of the HMOR-NA molecular sieve with a micro-meso-macroporous structure are: a specific surface area of ​​400–500 m². 2 / g, micropore volume is 0.1~0.3cm 3 / g, mesoporous pore volume is 0.3~0.5cm³ 3 / g, with micropore size of 0.1–2 nm and mesopore size of 2–180 nm; the structural parameters of the micro-meso-macroporous HY-NA molecular sieve are: specific surface area of ​​750–850 m² / g. 2 / g, micropore volume is 0.05~0.1cm 3 / g, mesoporous pore volume is 0.3~0.5cm³ 3 / g, with micropore sizes ranging from 0.2 to 2 nm and mesopore sizes ranging from 2 to 150 nm. The structural parameters of the HZSM-5-NA molecular sieve with a micro-meso-macroporous structure are: specific surface area of ​​300–400 m² / g. 2 / g, micropore volume is 0.02~0.1cm 3 / g, mesoporous pore volume is 0.2~0.5cm³3 / g, with micropore sizes ranging from 0.2 to 2 nm and mesopore sizes ranging from 2 to 200 nm. The structural parameters of the micro-meso-macroporous HBeta-5-NA molecular sieve are: specific surface area of ​​500–600 m² / g. 2 / g, with micropore volume of 0.1–0.2 cm³. 3 / g, mesoporous pore volume is 0.2~0.4cm 3 / g, with micropore size ranging from 0.1 to 2 nm and mesopore size ranging from 2 to 220 nm, not limited to this range of structural parameters.

[0009] As a preferred option, the HMOR-NA molecular sieve with a micro-meso-macroporous structure is synthesized, and its molar composition is 1.2Al2O3 / 6.6Na2O / 23SiO2 / 0.001~0.005ACC / 550H2O. Among them, ACC is a cationic copolymer containing quaternary ammonium groups.

[0010] The synthesis process of ACC is as follows: diallylamine and dimethyl diallyl ammonium chloride are added to a flask, followed by acrylic acid. The mixture is stirred until no smoke is observed, and the pH is adjusted to 6-7. The flask is then placed in a constant temperature water bath, and a catalyst solution (ammonium persulfate + water) is added dropwise while the temperature inside the flask reaches above 90°C. The reaction is stopped after 4 hours from the addition of the catalyst. Stirring is stopped once the temperature of the reaction solution drops below 50°C, and water is added to obtain a product with a dry matter content of 25%. The obtained cationic copolymer is designated as ACC. The mass ratio of diallylamine, dimethyl diallyl ammonium chloride, and acrylic acid is 210:1500:210.

[0011] The composition of the synthetic micro-meso-macroporous HY-NA molecular sieve: Y zeolite nanoparticle components (NANO-Y) were synthesized from aluminosilicate gel with a molar ratio of 1.5Al2O3 / 4.5Na2O / 10.0SiO2 / 0.9TMOAC / 160H2O, wherein TMOAC is N,N-diethyl-N-hexadecyl-(3-trimethoxysilylpropyl)ammonium chloride ([(CH3O)3SiC3H6N(C2H5)2C 16 H 33 Silanes of Cl).

[0012] The composition of the synthesized HZSM-5-NA molecular sieve with a micro-meso-macroporous structure is Al2O3 / 49SiO2 / 15.8Na2O / 0.016ACC / 1500H2O by molar ratio.

[0013] The composition of the synthesized micro-meso-macroporous HBeta-NA zeolite molecular sieve is as follows (molar composition): Al2O3 / 34SiO2 / 2Na2O / 0.01ACC / 2.8TPAOH / 286H2O.

[0014] As an improvement to the invention, based on the weight of the composite catalyst, the mass content of acidic nano-zeolite molecular sieve is 40% to 50%, and the mass content of acidic resin is 50% to 60%.

[0015] As an improvement of the present invention, the acidic nano-zeolite molecular sieve and acidic resin composite catalyst need to be extruded and sieved to finally collect 35-60 mesh particles.

[0016] As an improvement of the present invention, during the extrusion molding of the composite catalyst, based on the mass of the added acidic nano-zeolite molecular sieve and acidic resin, 50 wt.% distilled water and 0.5 wt.% concentrated nitric acid are added to facilitate extrusion.

[0017] As an improvement of the present invention, the composite catalyst is dried in an oven at 100°C for 12-24 hours after being extruded.

[0018] This invention also provides the application of the acidic nano-zeolite molecular sieve / acidic resin-based composite catalyst prepared by the above preparation method in the synthesis of triacetone amine.

[0019] The obtained catalyst was used in the reaction of acetone and ammonia to prepare triacetoneamine. The application method was as follows: 100-150g of the prepared composite catalyst was weighed and packed into a fixed-bed reactor (the inner diameter of the fixed-bed reactor was 3.2cm). Acetone and ammonia were introduced, and after the reaction system stabilized, the reactants were collected and analyzed by gas chromatography. The flow rate of acetone was 0.4-0.8mL / min, the feed flow rate of ammonia was 30-60mL / min, the molar ratio of acetone to ammonia was 2.6-6.6:1, the upper section temperature of the fixed-bed reactor was 30-50℃, and the lower section temperature was 50-60℃.

[0020] Preferred flow conditions: acetone flow rate 0.48–0.6 mL / min, ammonia flow rate 35–50 mL / min. Preferred temperature conditions: upper section temperature of the fixed-bed reactor 30–40℃, lower section temperature 50–56℃.

[0021] Beneficial effects:

[0022] (1) Through reasonable combination and regulation, the composite catalyst prepared in the composite catalyst can achieve higher selectivity for the target product triacetone amine in the reaction. In the composite catalyst, the pore size of the acidic nano-zeolite molecular sieve component (containing acidic nano-zeolite with micro-meso-macroporous structure) can selectively catalyze the reaction of reactants to generate acetone, which in turn generates triacetone amine with high selectivity on the resin of the catalyst component. Therefore, the Brønsted acidic sites (Si-Al-OH) of the acidic nano-zeolite molecular sieve component and the sulfonic acid sites of the resin component produce synergistic catalysis on the composite catalyst, which is beneficial to the reaction of acetone and ammonia to synthesize triacetone amine.

[0023] (2) The combination of resin components and molecular sieve components in the composite catalyst can superimpose their respective catalytic activities, thereby improving the overall catalytic activity. The molecular sieve component in the composite catalyst provides a highly ordered pore structure, which is conducive to the shape-selective catalysis of reactant molecules to generate acetone amine intermediate, while the sulfonic acid group active sites of the acid resin component can efficiently catalyze the conversion of the intermediate acetone amine into the target product triacetone amine;

[0024] (3) Composite catalysts exhibit better stability. Molecular sieve components, as highly ordered materials, possess high thermal and chemical stability, which helps maintain the structural stability of the catalyst. Simultaneously, resins, as macroporous materials with numerous sulfonic acid groups, facilitate the diffusion of reactants and products, contributing to maintaining the catalyst's high activity and lifespan. Attached Figure Description

[0025] Figure 1 This is a simplified diagram of a two-stage reactor. Detailed Implementation

[0026] The present invention will be further described below through specific embodiments, but the present invention is not limited to the following embodiments. The technical terms used in the following embodiments have the same meaning as commonly understood by those skilled in the art. Unless otherwise specified, the experimental reagents used in the following embodiments are all conventional reagents, which can be purchased commercially or synthesized according to conventional methods in the art; the experimental methods, unless otherwise specified, are all conventional methods. Although the following embodiments provide methods for preparing molecular sieves, they are not limited to this method; other synthesized or purchased micro-meso-macroporous acidic molecular sieves also meet the requirements.

[0027] Example 1

[0028] (1) Preparation of HMOR-NA molecular sieve with micro-meso-macroporous structure: MOR-NA has a molar composition of 1.2Al2O3 / 6.6Na2O / 23SiO2 / 0.005ACC / 550H2O. Water glass and an aqueous solution of 2.6wt.% NaAlO2 were mixed. After stirring at room temperature for 30 minutes, ACC was slowly added under vigorous stirring. After further stirring for 100 minutes, an aqueous solution of Al2(SO4)3 (8.0wt%) was added. After stirring at room temperature for 100 minutes, a viscous aluminosilicate gel was obtained. The gel was transferred to a stainless steel autoclave and crystallized at 170℃ for 3 days. After filtration and washing, the sample was dried at 120℃ overnight and calcined in air at 550℃ for 6 hours. The obtained sample was ion-exchanged with 1M NH4NO3 solution at 80℃ for 4 hours, and the resulting sample was named HMOR-NA. ACC is a cationic copolymer containing quaternary ammonium groups, synthesized using inexpensive materials. The synthesis process is as follows: 210g of diallylamine and 1500g of dimethyl diallyl ammonium chloride are added to a 3000mL three-necked flask, followed by the addition of 210g of acrylic acid. The mixture is stirred until no smoke is detected, and the pH is adjusted to 6-7. The flask is then placed in a 94°C constant temperature water bath, and 500mL of distilled water is added. While the temperature inside the flask reaches above 90°C, a catalyst solution (30g of ammonium persulfate + 150mL of water, added very slowly initially, completing the addition within 2 hours) is added dropwise. The reaction is stopped after 4 hours from the addition of the catalyst. Stirring is stopped once the temperature of the reaction solution drops below 50°C, and 4480mL of water is added to obtain a product with a dry matter content of 25%. The obtained cationic copolymer is designated as ACC.

[0029] (2) Weigh 80g of HMOR-NA molecular sieve with micro-meso-macroporous structure and 120g of commercially available Amberlyst 15 hydrogen-type resin (strong acid sulfonic acid group macroporous polystyrene ion exchange resin). After crushing in a pulverizer and mixing thoroughly, add 100g of distilled water and 1g of concentrated nitric acid, mix evenly, extrude into strips, and dry in an oven at 100℃ for 24 hours to obtain the target catalyst.

[0030] (3) Weigh 150g of the above-mentioned sieved catalyst and pack it into a fixed-bed reactor. Introduce acetone and ammonia. After the reaction system stabilizes, collect the reaction products and analyze them by gas chromatography. The average product yield was 59.2% after 240 hours of continuous operation. The catalyst was sieved to 35-60 mesh, the flow rate of acetone was 0.6 mL / min, the flow rate of ammonia was 50 mL / min, the molar ratio of acetone to ammonia was 3.9:1, the temperature of the upper section of the reactor was 30℃, and the temperature of the lower section was 55℃.

[0031] Example 2

[0032] The catalyst differs from step (2) of Example 1 in that the micro-meso-macroporous HMOR-NA molecular sieve is replaced with the micro-meso-macroporous HY-NA molecular sieve, while the other operations are the same, to obtain the composite catalyst.

[0033] Preparation of micro-meso-macroporous HY-NA molecular sieves: from a molar ratio of...

[0034] Y-zeolite nanoparticles (NANO-Y) were synthesized from an aluminosilicate gel consisting of 1.5Al₂O₃ / 4.5Na₂O / 10.0SiO₂ / 0.9TMOAC / 160H₂O, where TMOAC is N,N-diethyl-N-hexadecyl-(3-trimethoxysilylpropyl)ammonium chloride ([(CH₃O)₃SiC₃H₆N(C₂H₅)₂C 16 H 33 Silane (Cl) was used. Water glass, H2O, and a Y-type zeolite seed solution (NaAlO2, H2O, NaOH, and water glass were mixed and aged for 24 h). After further stirring for 200 min, an Al2(SO4)3 aqueous solution (50 wt.%), a NaAlO2 aqueous solution (20 wt.%), and a NaOH aqueous solution (10 wt.%) were added. The mixture was stirred at room temperature for 150 min, and the resulting aluminosilicate gel was transferred to a stainless steel autoclave for static crystallization at 90 °C for 2 days. After filtration and washing, the sample was dried overnight at 100 °C and calcined in air at 560 °C for 5 h. The resulting sample was then subjected to ion exchange with 1 M NH4NO3 solution at 80 °C for 4 h, and the resulting sample was named HY-NA.

[0035] The application procedure was the same as in Example 1. After the reaction stabilized, the reaction product was collected and analyzed by gas chromatography. The average product yield was 59.3% after 240 hours of continuous operation.

[0036] Example 3

[0037] The catalyst differs from step (2) of Example 1 in that the micro-meso-macroporous HMOR-NA molecular sieve is replaced with the micro-meso-macroporous HZSM-5-NA molecular sieve, while the other operations are the same, to obtain the composite catalyst.

[0038] Preparation of HZSM-5-NA molecular sieve with micro-meso-macroporous structure: HZSM-5-NA was hydrothermally synthesized from an aluminosilicate gel with a molar composition of Al2O3 / 49SiO2 / 15.8Na2O / 0.016ACC / 1500H2O. Water glass was mixed with an aqueous solution of NaOH (2.1 wt.%), and then the polymer copolymer ACC was added. After stirring at room temperature for 2 hours, an acidic Al2(SO4)3 aqueous solution (3.7 wt.%) was added. The mixture was further stirred for 2 hours to obtain the aluminosilicate gel. The gel was transferred to a stainless steel autoclave and dynamically crystallized at 170 °C for 3 days. After filtration and washing, the sample was dried at 120 °C for 12 hours and calcined in air at 550 °C for 5 hours. The resulting sample was subjected to ion exchange with 1M NH4NO3 solution at 80 °C for 4 hours, and the resulting sample was named HZSM-5-NA.

[0039] The application procedure is the same as in Example 1. After the reaction stabilizes, the reaction product is collected and analyzed by gas chromatography. The average product yield is 56.6% after 240 hours of continuous operation.

[0040] Example 4

[0041] The catalyst differs from step (2) of Example 1 in that the micro-meso-macroporous HMOR-NA molecular sieve is replaced with the micro-meso-macroporous HBeta-NA zeolite molecular sieve, while the other operations are the same, to obtain the composite catalyst.

[0042] Preparation of micro-meso-macroporous HBeta-NA zeolite molecular sieves: NaOH was dissolved in H2O under stirring, followed by the addition of NaAlO2 and 25 wt.% tetraethylammonium hydroxide (TPAOH). After stirring at room temperature for 1 hour, silica gel was added to the solution and stirred for another hour. The cationic copolymer ACC was added dropwise, and the mixture was stirred for 2 hours to obtain a gel. The gel composition was Al2O3 / 34SiO2 / 2Na2O / 0.01ACC / 2.8TPAOH / 286H2O. The gel was transferred to a 50L autoclave and dynamically crystallized at 140℃ for 5 days. The solid product was collected by filtration, dried, and calcined at 550℃ for 6 hours to remove the organic template.

[0043] The application procedure is the same as in Example 1. After the reaction stabilizes, the reaction product is collected and analyzed by gas chromatography. The average product yield is 57.5% after 240 hours of continuous operation.

[0044] Example 5

[0045] The molar composition of MOR-NA in Example 1 was changed from 1.2Al₂O₃ / 6.6Na₂O / 23SiO₂ / 0.005ACC / 550H₂O to 1.2Al₂O₃ / 6.6Na₂O / 23SiO₂ / 0.001ACC / 550H₂O, with other operations remaining the same as in Example 1. After the reaction stabilized, the reaction product was collected and analyzed by gas chromatography. The average product yield was 51.6% after 240 hours of continuous operation.

[0046] Example 6

[0047] The mass of the micro-meso-macroporous HMOR-NA molecular sieve added during extrusion in Example 1 was changed to 100g, and the mass of the acidic resin added was also changed to 100g. Other operations remained the same as in Example 1. After the reaction stabilized, the reaction product was collected and analyzed by gas chromatography. The average product yield was 56.8% after 240 hours of continuous operation.

[0048] Example 7

[0049] In step (3) of Example 1, the temperature of the upper section of the reactor was changed to 50°C, while other operations remained the same as in Example 1. After the reaction stabilized, the reaction product was collected and analyzed by gas chromatography. The average product yield was 49.7% after 240 hours of continuous operation.

[0050] Example 8

[0051] The temperature of the lower section of the reactor in step (3) of Example 1 was changed to 60°C, and other operations were the same as in Example 1. After the reaction stabilized, the reaction product was collected and analyzed by gas chromatography. The average product yield was 42.7% after 240 hours of continuous operation.

[0052] Example 9

[0053] The 150g catalyst in step (3) of Example 1 was replaced with 100g catalyst, and other operations were the same as in Example 1. After the reaction stabilized, the reaction product was collected and analyzed by gas chromatography. The average product yield was 47.5% after 240 hours of continuous operation.

[0054] Example 10

[0055] The acetone flow rate in step (3) of Example 1 was changed to 0.8 mL / min, and other operations were the same as in Example 1. After the reaction stabilized, the reaction product was collected and analyzed by gas chromatography. The average product yield was 44.2% after 240 hours of continuous operation. The molar ratio of acetone to ammonia was 5.2:1.

[0056] Comparative Example 1

[0057] The micro-mesoporous-macroporous HMOR-NA molecular sieve in step (1) was replaced with a conventional HZSM-5 molecular sieve (non-mesoporous, mostly microporous). Preparation of HZSM-5 molecular sieve: HZSM-5 is composed of a molar composition of...

[0058] Aluminosilicate gel of Al2O3 / 49SiO2 / 15.8Na2O / 1500H2O was hydrothermally synthesized. Water glass was mixed with an aqueous solution of NaOH (2.1 wt.%). After stirring at room temperature for 2 hours, an acidic aqueous solution of Al2(SO4)3 (3.7 wt.%) was added. The mixture was further stirred for 2 hours to obtain the aluminosilicate gel. The gel was transferred to a stainless steel autoclave and dynamically crystallized at 170 °C for 3 days. After filtration and washing, the sample was dried at 120 °C for 12 hours and calcined in air at 550 °C for 5 hours. The resulting sample was then subjected to ion exchange with 1M NH4NO3 solution at 80 °C for 4 hours, and the resulting sample was named HZSM-5.

[0059] Other procedures were the same as in Example 1. After the reaction stabilized, the reaction product was collected and analyzed by gas chromatography. The average product yield was 41.4% after 240 hours of continuous operation.

[0060] Comparative Example 2

[0061] The composite catalyst in Example 1 was replaced with a separate micro-meso-macroporous HMOR-NA molecular sieve catalyst:

[0062] (1) Weigh 200g of micro-meso-macroporous HMOR-NA molecular sieve (preparation method is the same as in Example 1), add 100g of distilled water and 1g of concentrated nitric acid, mix evenly, extrude into strips, dry in an oven at 100°C for 24 hours, and then calcine in air at 550°C for 5 hours to obtain the target catalyst.

[0063] (2) Weigh 150g of the above-mentioned sieved catalyst and pack it into a self-made fixed-bed reactor. Acetone and ammonia are introduced. After the reaction system stabilizes, the reaction product is collected and analyzed by gas chromatography. The average product yield is 37.6% after 240 hours of continuous operation. The catalyst is sieved to 35-60 mesh, the flow rate of acetone is 0.6 mL / min, the flow rate of ammonia is 50 mL / min, the molar ratio of acetone to ammonia is 3.9:1, the temperature of the upper section of the reactor is 30℃, and the temperature of the lower section is 55℃.

[0064] Comparative Example 3

[0065] The composite catalyst in Example 1 was replaced with a separate micro-meso-macroporous HY-NA molecular sieve catalyst (preparation method as in Example 2). Other operations were the same as in Example 1. After the reaction stabilized, the reaction product was collected and analyzed by gas chromatography. The average product yield was 37.2% after 240 hours of continuous operation.

[0066] Comparative Example 4

[0067] The composite catalyst in Example 1 was replaced with a separate micro-meso-macroporous HBeta-NA molecular sieve catalyst (preparation method as in Example 4). Other operations were the same as in Example 1. After the reaction stabilized, the reaction product was collected and analyzed by gas chromatography. The average product yield was 34.2% after 240 hours of continuous operation.

[0068] Comparative Example 5

[0069] The composite catalyst in Example 1 was replaced with a separate HZSM-5-NA molecular sieve catalyst (prepared using the same method as in Example 2) (prepared using the same method as in Example 3). Other operations were the same as in Example 1. After the reaction stabilized, the reaction product was collected and analyzed by gas chromatography. The average product yield was 35.5% after 240 hours of continuous operation.

[0070] Comparative Example 6

[0071] The composite catalyst in Example 1 was replaced with a composite catalyst of commercially available amberlite IRC120H hydrogen form resin and acid-washed modified USY (silicon-to-aluminum ratio of 9.8). Using commercial USY as the parent material, USY molecular sieves were treated with 0.6 mol / L sulfuric acid at 50°C for 8 h, with an acid volume to USY molecular sieve mass ratio of 8 mL:1 g. The solid product obtained by centrifugation was washed with distilled water until neutral, then dried at 120°C for 12 h, and finally calcined in a muffle furnace at 550°C for 6 h to obtain acid-washed modified USY molecular sieves.

[0072] (1) Weigh 80g of acid-washed modified USY molecular sieve and 120g of commercially available strong acid sulfonic acid macroporous polystyrene ion exchange resin. After crushing them in a pulverizer and mixing them thoroughly, add 100g of distilled water and 1g of concentrated nitric acid, mix them evenly, extrude them into strips, and dry them in an oven at 100°C for 24 hours to obtain the target catalyst.

[0073] (2) Weigh 150g of the sieved catalyst from the above-mentioned extruded strips and pack it into a fixed-bed reactor. Acetone and ammonia were introduced. After the reaction system stabilized, the reaction products were collected and analyzed by gas chromatography. The average product yield was 59.2% after 240 hours of continuous operation. The catalyst was sieved to 35-60 mesh, the acetone flow rate was 0.6 mL / min, the ammonia flow rate was 50 mL / min, the molar ratio of acetone to ammonia was 3.9:1, the upper section temperature of the reactor was 30℃, and the lower section temperature was 55℃. After the reaction stabilized, the reaction products were collected and analyzed by gas chromatography. The average product yield was 40.5% after 240 hours of continuous operation.

[0074] Comparative Example 7

[0075] (1) Weigh 200g of commercially available Supelco 06423amberlyst 15 hydrogen form resin, add 100g of distilled water and 1g of concentrated nitric acid, mix evenly, extrude into strips, and dry in an oven at 100℃ for 24 hours to obtain the target catalyst.

[0076] (2) Weigh 150g of the above-mentioned extruded resin (after sieving) and pack it into a self-made fixed-bed reactor. Acetone and ammonia are introduced. After the reaction system stabilizes, the reaction product is collected and analyzed by gas chromatography. The average product yield is 36.7% after 240 hours of continuous operation. The catalyst is sieved to 35-60 mesh, the flow rate of acetone is 0.6 mL / min, the flow rate of ammonia is 50 mL / min, the molar ratio of acetone to ammonia is 3.9:1, the temperature of the upper section of the reactor is 30℃, and the temperature of the lower section is 55℃.

[0077] Comparative Example 8

[0078] (1) Weigh 200g of commercially available Supelco 216399amberlyst 15 hydrogen form resin, add 100g of distilled water and 1g of concentrated nitric acid, mix evenly, extrude into strips, and dry in an oven at 100℃ for 24 hours to obtain the target catalyst.

[0079] (2) Weigh 150g of the above-mentioned extruded resin after sieving and pack it into a self-made fixed-bed reactor. Acetone and ammonia were introduced. After the reaction system stabilized, the reaction product was collected and analyzed by gas chromatography. The average product yield was 36.2% after 240 hours of continuous operation. The catalyst was sieved to 35-60 mesh, the flow rate of acetone was 0.6 mL / min, the flow rate of ammonia was 50 mL / min, the molar ratio of acetone to ammonia was 3.9:1, the temperature of the upper section of the reactor was 30℃, and the temperature of the lower section was 55℃.

[0080] Comparative Example 9

[0081] (1) Weigh 200g of commercially available Supelco 06428amberlite IRC120H hydrogen form resin, add 100g of distilled water and 1g of concentrated nitric acid, mix evenly, extrude into strips, and dry in an oven at 100℃ for 24 hours to obtain the target catalyst.

[0082] (2) Weigh 150g of the above-mentioned extruded resin (after sieving) and pack it into a self-made fixed-bed reactor. Acetone and ammonia were introduced. After the reaction system stabilized, the reaction product was collected and analyzed by gas chromatography. The average product yield was 38.4% after 240 hours of continuous operation. The catalyst was sieved to 35-60 mesh, the flow rate of acetone was 0.6 mL / min, the flow rate of ammonia was 50 mL / min, the molar ratio of acetone to ammonia was 3.9:1, the temperature of the upper section of the reactor was 30℃, and the temperature of the lower section was 55℃.

[0083] Comparative Example 10

[0084] The composite catalyst in Example 1 was replaced with a composite catalyst of HMOR-NA molecular sieve with a micro-meso-macroporous structure and alumina. Commercial Dalian SB powder was used as the matrix and composited with the HMOR-NA molecular sieve from Example 1. 100g of the prepared HMOR-NA molecular sieve and 100g of Dalian SB powder were weighed, added to 100g of distilled water and 1g of concentrated nitric acid, mixed evenly, and extruded. After drying in an oven at 100°C for 24 hours, the target catalyst was obtained. Finally, it was calcined in a muffle furnace at 550°C for 6 hours to obtain the composite catalyst of HMOR-NA molecular sieve and alumina. Other operations were the same as in Example 1. After the reaction stabilized, the reaction product was collected and analyzed by gas chromatography. The average yield was 37.6% after 240 hours of continuous operation.

[0085] The embodiments described above are preferred embodiments of the present invention, but the present invention is not limited to the above embodiments. Any obvious improvements, substitutions or modifications that can be made by those skilled in the art without departing from the essence of the present invention shall fall within the protection scope of the present invention.

Claims

1. An application of a composite porous solid acid catalyst, characterized in that, Composite porous solid acid catalysts are used to catalyze the continuous reaction of acetone and ammonia to produce triacetone amine; The composite porous solid acid catalyst is obtained by mechanically mixing acidic nano-zeolite molecular sieves with acidic ion exchange resin containing sulfonic acid groups, molding, and drying. Based on the weight of the composite porous solid acid catalyst, the mass content of acidic nano-zeolite molecular sieve is 40%~50%, and the mass content of acidic ion exchange resin with sulfonic acid groups is 50%~60%. The acidic nano-zeolite molecular sieve has a micro-meso-macroporous structure; specifically, it is one or a combination of two or more of the porous HMOR-NA molecular sieve, HBeta-NA molecular sieve, HZSM-5-NA molecular sieve and HY-NA type molecular sieve with a micro-meso-macroporous structure; the acidic ion exchange resin with sulfonic acid groups is one or a combination of amberlyst 15 hydrogen form resin and amberlite IRC120H hydrogen form resin.

2. The application as described in claim 1, characterized in that, The forming process involves extruding the material into strips using an extruder; after extrusion, the strips are sieved to collect 35-60 mesh particles.

3. The application as described in claim 1, characterized in that, The composite porous solid acid catalyst was weighed and packed into a fixed-bed reactor. Acetone and ammonia were introduced. After the reaction system stabilized, the reaction products were collected and analyzed by gas chromatography.

4. The application as described in claim 1, characterized in that, The fixed-bed reactor is a two-stage reactor; the flow rate of acetone is 0.4~0.8 mL / min, the feed flow rate of ammonia is 30~60 mL / min, the molar ratio of acetone to ammonia is 2.6~6.6:1, the temperature of the upper section of the fixed-bed reactor is 30~50℃, and the temperature of the lower section is 50~60℃.

5. The application as described in claim 4, characterized in that, The acetone flow rate is 0.48~0.6 mL / min, and the ammonia flow rate is 35~50 mL / min; the upper section temperature of the fixed bed reactor is 30~40℃, and the lower section temperature is 50~56℃.

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