Method for synthesizing isopropyl toluene from toluene and propylene
By using Beta@ZSM-12 core-shell molecular sieve with adjustable core-shell ratios as catalysts, the problem of difficulty in controlling catalyst corrosion and reactivity in the prior art is solved, and the activity and selectivity of toluene and propylene can be regulated, which promotes the development of isopropyl toluene production technology.
Patent Information
- Application Number
- CN202411748043.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-11-29
- Publication Date
- 2025-03-18
AI Technical Summary
The prior art has the problem that catalysts are prone to equipment corrosion in the alkylation reaction between toluene and propylene, and it is difficult to effectively regulate the reaction activity and product selectivity.
Beta@ZSM-12 core-shell molecular sieve with adjustable core-shell ratios is used as a catalyst to adjust the reaction activity and reduce the selectivity of ortho-products by changing the ratio of shell ZSM-12.
In the synthesis of isopropyl toluene with liquid phase alkylation of toluene and propylene, the reaction activity and product selectivity can be adjusted, reducing the selectivity of o-isopropyl toluene by less than 4%, which is conducive to promoting the development of isopropyl toluene production technology.
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Figure CN119638546A_ABST
Abstract
Description
Technical Field
[0001] The present application relates to a method for synthesizing isopropylbenzene from toluene and propylene, and belongs to the field of fine chemicals. Background Art
[0002] Isopropylbenzene is a key raw material for specialty polymer monomers, and its downstream products are widely used in fragrances, high molecular polymers, herbicides, pesticides, etc. The currently reported industrial production method is toluene-propylene alkylation catalyzed by aluminum chloride hydrochloric acid complex catalyst, and the product is mainly meta-isopropylbenzene, p:m:o=28.7:69.7:1.6, but there is a disadvantage that the catalyst is prone to cause equipment corrosion, and it is necessary to develop an efficient and environmentally friendly catalyst suitable for industrial production.
[0003] When molecular sieve catalysts are used for toluene-propylene alkylation, they have attracted much attention due to their shape selectivity. Sun et al. investigated that compared with solid phosphoric acid, molecular sieve catalysts showed lower ortho-selectivity, and molecular sieve catalysts with different structures showed different isopropyl toluene product comparisons (Petrochemical Technology, 1996, 6 (3), 129-133). Wichterlova et al. believed that Beta and Y molecular sieves with three-dimensional open structures and ZSM-12 molecular sieves with one-dimensional structures are conducive to the synthesis of isopropyl toluene, and Fe-modified ZSM-5 has higher para-product selectivity (Microporous Materials 6 (1996) 405-414). Guo et al. reported the reaction performance of toluene and propylene on HZSM-12 catalyst. Under different reaction conditions, HZSM-12 catalyst can show lower ortho-selectivity (4%-7%), and the comparison is about 2 (Acta Petrolei Sinica, 1993, 9, 42-48). He et al. found that compared with molecular sieves of other structures, the alkylation reaction of toluene with propylene over Beta molecular sieve at 400° C. had a higher conversion rate of 34.2% and a para-selectivity of 42.2% (Advanced Materials Research. 2011, 396-398, 739-744).
[0004] Beta molecular sieve is a microporous molecular sieve with a three-dimensional twelve-membered ring pore system (0.76nm×0.67nm), and ZSM-12 molecular sieve is a microporous molecular sieve with a one-dimensional twelve-membered ring straight pore structure (0.57nm×0.61nm). The above study found that Beta and ZSM-12 molecular sieves showed superior activity and different product comparisons in the reaction of toluene and propylene than other types of molecular sieves. Combining the advantages of both, the core-shell structured Beta@ZSM-12 molecular sieve is expected to show higher activity and fewer by-products in this reaction. However, there is currently no report on the preparation method of the core-shell structured Beta@ZSM-12 catalyst and its use in the synthesis of isopropyl toluene. Summary of the invention
[0005] The present invention provides a method for synthesizing isopropyl toluene from toluene and propylene, wherein the main body of the catalyst is a Beta@ZSM-12 core-shell molecular sieve with an adjustable core-shell ratio. By changing the shell ZSM-12 ratio, the alkylation reaction of toluene and propylene exhibits adjustable activity and low ortho-product selectivity.
[0006] According to one aspect of the present application, there is provided a method for synthesizing isopropylbenzene from toluene and propylene, comprising the following steps:
[0007] In a reactor, a raw material containing toluene and propylene is contacted with a catalyst to undergo an alkylation reaction to obtain a product containing isopropyl toluene;
[0008] The catalyst consists of a binder and an alkali-treated Beta@ZSM-12 core-shell molecular sieve.
[0009] The temperature of the alkylation reaction is 150-240°C;
[0010] The pressure of the alkylation reaction is 2.0-3.5 MPa;
[0011] In the raw material, the molar ratio of toluene to propylene is 3 to 10;
[0012] In the raw material, the space velocity of propylene is 0.1~1.0h -1 .
[0013] The alkali-treated Beta@ZSM-12 core-shell molecular sieve has Beta molecular sieve as the core and ZSM-12 molecular sieve as the shell;
[0014] In the alkali-treated Beta@ZSM-12 core-shell molecular sieve, the mass content of the ZSM-12 molecular sieve as the shell is 10-40wt%.
[0015] The catalyst is prepared by the following steps:
[0016] (1) treating the sodium type Beta@ZSM-12 core-shell molecular sieve with alkali, washing with water for 1 time, and drying for 1 time to obtain the Beta@ZSM-12 core-shell molecular sieve after alkali treatment;
[0017] (2) Mixing a binder, sesbania powder, and alkali-treated Beta@ZSM-12 core-shell molecular sieve, adding an acid solution, kneading, extruding, drying II, calcining I, ion exchange, washing II, drying III, and calcining II to obtain the catalyst.
[0018] The alkali treatment uses 0.05-0.5 mol / L sodium hydroxide solution;
[0019] The temperature of the alkali treatment is 40 to 80°C;
[0020] The alkali treatment time is 30 to 180 minutes;
[0021] In the alkaline treatment, the liquid-solid mass ratio of the sodium hydroxide solution to the sodium-type Beta@ZSM-12 core-shell molecules is 4 to 8:1;
[0022] The temperature of the water washing I is 40-80°C;
[0023] The time of the water washing I is 0.5 to 1.5 hours;
[0024] The number of times of washing I is 2 to 4 times;
[0025] In the water washing I, the mass ratio of water to solid matter is 5 to 10:1.
[0026] The drying temperature is 90-110°C;
[0027] The drying time is 4 to 10 hours.
[0028] The mass ratio of the binder to the alkali-treated Beta@ZSM-12 core-shell molecular sieve is 10-40:60-90;
[0029] The mass of the sesbania powder is 3-5wt% of the total mass of the binder and the alkali-treated Beta@ZSM-12 core-shell molecular sieve;
[0030] The acid solution is a dilute nitric acid solution with a mass concentration of 8 to 12%;
[0031] The mass ratio of the total mass of the binder and the alkali-treated Beta@ZSM-12 core-shell molecular sieve to the acid solution is 0.4-0.8:1.
[0032] The drying temperature of II is 90-110°C;
[0033] The drying time II is 10 to 24 hours;
[0034] The temperature of the calcination I is 520-550° C.
[0035] The calcination time is 4 to 8 hours.
[0036] The ion exchange uses dilute hydrochloric acid with a concentration of 0.1-0.3 mol / L or 0.4-0.8 mol / L ammonium chloride solution;
[0037] The temperature of the ion exchange is 60-80°C;
[0038] The ion exchange time is 60 to 120 minutes;
[0039] The drying temperature of III is 90-110°C;
[0040] The drying time of III is 4 to 10 hours;
[0041] The temperature of the calcination II is 490-510°C;
[0042] The calcination time of II is 3 to 6 hours.
[0043] The temperature of the water washing II is 60-80°C;
[0044] The time of the water washing II is 0.5 to 1.5 hours;
[0045] The number of times of washing II is 2 to 4 times;
[0046] In the water washing II, the mass ratio of water to solid matter is 4-6:1.
[0047] The beneficial effects of this application include:
[0048] The present application proposes a method for synthesizing isopropylbenzene from toluene and propylene, which uses a Beta@ZSM-12 catalyst with a multi-level pore core-shell structure, is simple in preparation and easy to industrialize, and has an adjustable core-shell ratio and a multi-level pore structure. It exhibits adjustable reaction activity and low ortho-product selectivity in the reaction of toluene and propylene liquid phase alkylation to synthesize isopropylbenzene, and the selectivity of ortho-isopropylbenzene in isopropylbenzene is less than 4%. It is beneficial to promote the development of isopropylbenzene production technology. BRIEF DESCRIPTION OF THE DRAWINGS
[0049] Figure 1 This is an electron microscope image of the multi-level porous core-shell molecular sieve after alkali treatment in Example 1, with a scale of 1 μm. DETAILED DESCRIPTION
[0050] The present application is described in detail below with reference to embodiments, but the present application is not limited to these embodiments.
[0051] Ingredients:
[0052] Sodium Beta @ ZSM-12 core-shell molecular sieve (ZSM-12 mass percentage is 40%), dry basis 90% Sodium Beta @ ZSM-12 core-shell molecular sieve (ZSM-12 mass percentage is 30%), dry basis 87% Sodium Beta @ ZSM-12 core-shell molecular sieve (ZSM-12 mass percentage is 25%), dry basis 87% Sodium Beta @ ZSM-12 core-shell molecular sieve (ZSM-12 mass percentage is 10%), dry basis 85% Alumina, dry basis 71%
[0053] Sodium Beta molecular sieve, dry basis 82%;
[0054] Sodium ZSM-12 molecular sieve, dry basis 92%
[0055] Example 1
[0056] Preparation of catalyst: (1) According to the liquid-solid mass ratio of 8:1, 333.3 g of sodium-type Beta@ZSM-12 core-shell molecular sieve (the mass percentage of ZSM-12 molecular sieve is 40%) was mixed with 2666.7 g of 0.05 mol / L sodium hydroxide solution, and alkali-treated at 80°C for 30 min; then, according to the liquid-solid mass ratio of 10:1, 3333.3 g of water was washed at 80°C for 3 times, each time for 1 h; finally, dried at 110°C for 4 h to obtain the alkali-treated sodium-type Beta@ZSM-12 core-shell molecular sieve a1, whose electron microscope image is shown as follows Figure 1 As shown. The dry basis of a1 was measured to be 88%. (2) 200g of alkali-treated sodium-type Beta@ZSM-12 core-shell molecular sieve a1 and 43.7g of alumina were mixed at a dry basis weight percentage of 85%:15%, and then 10.3g of sesbania powder accounting for 5% of the total dry basis weight was added and mixed evenly, and 414.1g of 10% dilute nitric acid solution with a mass concentration of 0.5:1 with the total dry basis weight ratio was used to knead and extrude the mixture into strips, and then dried at 100°C for 12h and calcined at 520°C for 6h to obtain the molded product b1. The dry basis of b1 was measured to be 87%. (3) According to the liquid-to-solid mass ratio of 5:1, 200 g of the molded product b1 was mixed with 870.0 g of 0.8 mol / L ammonium chloride solution for ammonium exchange at 80°C for 60 min; then, it was mixed with 1044.0 g of water at a liquid-to-solid mass ratio of 6:1, washed with water at 60°C for 3 times, each time for 1 h; finally, it was dried at 110°C for 10 h and calcined at 510°C for 3 h to obtain catalyst A1.
[0057] The reaction conditions were 220°C, 3.5 MPa, a toluene to propylene molar ratio of 5.0, and a propylene space velocity of 0.3 h -1 Under the above conditions, the toluene and propylene reaction activity of catalyst A1 was evaluated. The catalyst activity after 24 h of reaction and the selectivity of each isomer of isopropyl toluene are listed in Table 1.
[0058] Comparative Example 1
[0059] In Example 1, the sodium Beta@ZSM-12 core-shell molecular sieve (the mass percentage of ZSM-12 molecular sieve is 40%) is replaced with a mixture of sodium Beta and sodium ZSM-12 molecular sieves, the proportion of ZSM-12 molecular sieve in the mixture is 40%, the amount of sodium Beta molecular sieve (dry basis 82%) added is 219.5 g, the amount of sodium ZSM-12 molecular sieve (dry basis 92%) added is 130.4 g, and the preparation process of the remaining catalysts is the same as in Example 1 to obtain catalyst D1.
[0060] The conditions for the alkylation reaction of toluene and propylene using catalyst D1 are the same as those for catalyst A1. The catalyst activity after 24 hours of reaction and the selectivity of each isomer of isopropyl toluene are listed in Table 1.
[0061] Comparative Example 2
[0062] In the catalyst preparation process of Example 1, the alkali treatment step was omitted, and the preparation process of the remaining catalysts was the same as in Example 1 to obtain catalyst D2.
[0063] The conditions for the alkylation of toluene and propylene using catalyst D2 are the same as those for catalyst A1. The catalyst activity after 24 hours of reaction and the selectivity of each isomer of isopropyl toluene are listed in Table 1.
[0064] Example 2
[0065] Preparation of catalyst: (1) According to the liquid-solid mass ratio of 4:1, 300g of sodium-type Beta@ZSM-12 core-shell molecular sieve (the mass percentage of ZSM-12 molecular sieve is 30%) was mixed with 1379.3g of 0.05mol / L sodium hydroxide solution, and alkali-treated at 40°C for 180min; then, according to the liquid-solid mass ratio of 5:1, 1724.1g of water was washed at 40°C for 3 times, each time for 1h; finally, dried at 110°C for 4h to obtain the sodium-type Beta@ZSM-12 core-shell molecular sieve a2 after alkali treatment. The dry basis of a2 was measured to be 85%. (2) 200 g of sodium-type Beta@ZSM-12 core-shell molecular sieve a2 treated with alkali and 26.6 g of alumina were mixed in a dry basis weight percentage of 90%:10%, and then 9.4 g of sesbania powder accounting for 5% of the total dry basis weight was added and mixed evenly, and the mixture was kneaded and extruded into strips with a mass concentration of 236.1 g of 12% dilute nitric acid solution with a dry basis weight ratio of 0.8:1, and then dried at 110° C. for 10 h and calcined at 550° C. for 4 h to obtain a molded product b2. The dry basis weight of b2 was measured to be 84%. (3) According to the liquid-to-solid mass ratio of 5:1, 200 g of the molded product b2 was mixed with 840.0 g of 0.8 mol / L ammonium chloride solution for ammonium exchange at 80°C for 60 min; then, it was mixed with 1008.0 g of water at a liquid-to-solid mass ratio of 6:1, washed with water at 60°C for 3 times, each time for 1 h; finally, it was dried at 110°C for 10 h and calcined at 510°C for 3 h to obtain catalyst A2.
[0066] The conditions for the alkylation reaction of toluene and propylene using catalyst A2 are the same as those for catalyst A1. The catalyst activity after 24 hours of reaction and the selectivity of each isomer of isopropyl toluene are listed in Table 1.
[0067] Example 3
[0068] Preparation of catalyst: (1) According to the liquid-solid mass ratio of 6:1, 300g of sodium-type Beta@ZSM-12 core-shell molecular sieve (the mass percentage of ZSM-12 molecular sieve is 25%) was mixed with 2069.0g of 0.1mol / L sodium hydroxide solution, and alkali-treated at 80°C for 30min; then, according to the liquid-solid mass ratio of 10:1, 3448.3g of water was washed at 60°C for 3 times, each time for 1h; finally, dried at 90°C for 10h to obtain the sodium-type Beta@ZSM-12 core-shell molecular sieve a3 after alkali treatment. The dry basis of a3 was measured to be 85%. (2) 200 g of sodium-type Beta@ZSM-12 core-shell molecular sieve a3 treated with alkali and 159.6 g of alumina were mixed in a dry basis weight percentage of 60%:40%, and then 8.5 g of sesbania powder accounting for 3% of the total dry basis weight was added and mixed evenly, and the mixture was kneaded and extruded into strips with a mass concentration of 708.3 g of 8% dilute nitric acid solution with a dry basis weight ratio of 0.4:1, and then dried at 90°C for 24 h and calcined at 550°C for 8 h to obtain a molded product b3. The dry basis weight of b3 was measured to be 84%. (3) According to the liquid-to-solid mass ratio of 3:1, 200 g of the molded product b3 was mixed with 504.0 g of 0.4 mol / L ammonium chloride solution for ammonium exchange at 60°C for 120 min; then, it was mixed with 672.0 g of water at a liquid-to-solid mass ratio of 4:1, washed with water at 60°C for 3 times, each time for 1 h; finally, it was dried at 110°C for 10 h and calcined at 510°C for 3 h to obtain catalyst A3.
[0069] The conditions for the alkylation reaction of toluene and propylene using catalyst A3 are the same as those for catalyst A1. The catalyst activity after 24 hours of reaction and the selectivity of each isomer of isopropyl toluene are listed in Table 1.
[0070] Example 4
[0071] Preparation of catalyst: (1) According to the liquid-solid mass ratio of 8:1, 300g of sodium-type Beta@ZSM-12 core-shell molecular sieve (the mass percentage of ZSM-12 molecular sieve is 10%) was mixed with 2823.5g of 0.5mol / L sodium hydroxide solution, and alkali-treated at 40°C for 30min; then, according to the liquid-solid mass ratio of 10:1, 3529.4g of water was washed 3 times at 60°C, each time for 1h; finally, dried at 110°C for 4h to obtain the sodium-type Beta@ZSM-12 core-shell molecular sieve a4 after alkali treatment. The dry basis of a4 was measured to be 84%. (2) 200 g of sodium-type Beta@ZSM-12 core-shell molecular sieve a4 treated with alkali and 26.3 g of alumina were mixed in a dry basis weight percentage of 90%:10%, and then 9.3 g of sesbania powder accounting for 5% of the total dry basis weight was added and mixed evenly, and the mixture was kneaded and extruded into strips with a mass concentration of 233.3 g of 12% dilute nitric acid solution with a dry basis weight ratio of 0.8:1, and then dried at 110° C. for 10 h and calcined at 540° C. for 4 h to obtain a molded product b4. The dry basis weight of b4 was measured to be 83%. (3) According to the liquid-solid mass ratio of 5:1, 200 g of the molded product b4 was mixed with 830.0 g of 0.8 mol / L ammonium chloride solution for ammonium exchange at 80°C for 60 min; then, it was mixed with 830.0 g of water at a liquid-solid mass ratio of 5:1, washed with water at 80°C for 3 times, each time for 1 h; finally, it was dried at 90°C for 4 h and calcined at 510°C for 3 h to obtain catalyst A4.
[0072] The conditions for the alkylation reaction of toluene and propylene using catalyst A4 are the same as those for catalyst A1. The catalyst activity after 24 hours of reaction and the selectivity of each isomer of isopropyl toluene are listed in Table 1.
[0073] Table 1 Propylene and toluene reaction activity and selectivity of catalysts in the examples
[0074]
[0075] The above are only a few embodiments of the present application and do not constitute any form of limitation to the present application. Although the present application is disclosed as above with preferred embodiments, it is not intended to limit the present application. Any technician familiar with the profession, without departing from the scope of the technical solution of the present application, using the technical content disclosed above to make slight changes or modifications are equivalent to equivalent implementation cases and fall within the scope of the technical solution.
Claims
1. A method for synthesizing isopropylbenzene from toluene and propylene, characterized in that: The following steps are involved: In a reactor, a raw material containing toluene and propylene is contacted with a catalyst to undergo an alkylation reaction to obtain a product containing isopropyl toluene; The catalyst consists of a binder and an alkali-treated Beta@ZSM-12 core-shell molecular sieve.
2. The method according to claim 1, characterized in that The temperature of the alkylation reaction is 150-240°C; The pressure of the alkylation reaction is 2.0-3.5 MPa; In the raw material, the molar ratio of toluene to propylene is 3 to 10; In the raw material, the space velocity of propylene is 0.1~1.0h -1 .
3. The method according to claim 1, characterized in that The alkali-treated Beta@ZSM-12 core-shell molecular sieve has Beta molecular sieve as the core and ZSM-12 molecular sieve as the shell; In the alkali-treated Beta@ZSM-12 core-shell molecular sieve, the mass content of the ZSM-12 molecular sieve as the shell is 10-40wt%.
4. The method according to claim 1, characterized in that: The catalyst is prepared by the following steps: (1) treating the sodium type Beta@ZSM-12 core-shell molecular sieve with alkali, washing with water for 1 time, and drying for 1 time to obtain the Beta@ZSM-12 core-shell molecular sieve after alkali treatment; (2) Mixing a binder, sesbania powder, and alkali-treated Beta@ZSM-12 core-shell molecular sieve, adding an acid solution, kneading, extruding, drying II, calcining I, ion exchange, washing II, drying III, and calcining II to obtain the catalyst.
5. The method according to claim 4, characterized in that The alkali treatment uses 0.05-0.5 mol / L sodium hydroxide solution; The temperature of the alkali treatment is 40 to 80°C; The alkali treatment time is 30 to 180 minutes; In the alkaline treatment, the liquid-solid mass ratio of the sodium hydroxide solution to the sodium-type Beta@ZSM-12 core-shell molecules is 4 to 8:1; The temperature of the water washing I is 40-80°C; The time of the water washing I is 0.5 to 1.5 hours; The number of times of washing I is 2 to 4 times; In the water washing I, the mass ratio of water to solid matter is 5 to 10:
1. The drying temperature is 90-110°C; The drying time is 4 to 10 hours.
6. The method according to claim 4, characterized in that The mass ratio of the binder to the alkali-treated Beta@ZSM-12 core-shell molecular sieve is 10-40:60-90; The mass of the sesbania powder is 3-5wt% of the total mass of the binder and the alkali-treated Beta@ZSM-12 core-shell molecular sieve; The acid solution is a dilute nitric acid solution with a mass concentration of 8 to 12%; The mass ratio of the total mass of the binder and the alkali-treated Beta@ZSM-12 core-shell molecular sieve to the acid solution is 0.4-0.8:
1.
7. The method according to claim 4, characterized in that The drying temperature of II is 90-110°C; The drying time II is 10 to 24 hours; The temperature of the calcination I is 520-550° C. The calcination time is 4 to 8 hours.
8. The method according to claim 4, characterized in that The ion exchange uses dilute hydrochloric acid with a concentration of 0.1-0.3 mol / L or 0.4-0.8 mol / L ammonium chloride solution; The temperature of the ion exchange is 60-80°C; The ion exchange time is 60 to 120 minutes; The drying temperature of III is 90-110°C; The drying time of III is 4 to 10 hours; The temperature of the calcination II is 490-510°C; The calcination time of II is 3 to 6 hours. The temperature of the water washing II is 60-80°C; The time of the water washing II is 0.5 to 1.5 hours; The number of times of washing II is 2 to 4 times; In the water washing II, the mass ratio of water to solid matter is 4-6:1.