A process for the preparation of diisopropylbenzene
By modifying the eutectic molecular sieve catalyst and adjusting the ratio of Beta and MOR molecular sieves and the pore structure, the problems of uncontrollable catalyst stability and o-diisopropylbenzene selectivity were solved, and efficient control of diisopropylbenzene selectivity and industrial production were achieved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- DALIAN INSTITUTE OF CHEMICAL PHYSICS CHINESE ACADEMY OF SCIENCES
- Filing Date
- 2024-12-02
- Publication Date
- 2026-06-02
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Figure BDA0005167083980000061 
Figure BDA0005167083980000071
Abstract
Description
Technical Field
[0001] This application relates to a method for preparing diisopropylbenzene, which belongs to the field of chemical engineering. Background Technology
[0002] Diisopropylbenzene, especially p-diisopropylbenzene and m-diisopropylbenzene, is a raw material for the synthesis of polyester fibers, plastics, and rubber, as well as for pharmaceuticals, pesticides, fragrances, and fuels. Its applications and demand are rapidly expanding with the development of human society and the chemical industry. Therefore, developing efficient and environmentally friendly diisopropylbenzene synthesis processes has become a focus of research.
[0003] Currently, there are few reports on the alkylation of cumene to prepare dicumene, and systematic research on this process route is lacking. CN115041225A discloses a catalyst and its preparation method for reducing the selectivity of o-dicumene in mixed dicumene via isomerization reaction, using Beta or MCM-22 molecular sieves as the catalyst. CN118666624A discloses a method for preparing dicumene using isopropanol as the alkylating agent, employing an indium-modified molecular sieve catalyst to catalyze the alkylation of cumene to dicumene. CN116444333A provides a method for alkylating and converting o-dicumene in dicumene, which can improve the purity of m-dicumene and p-dicumene.
[0004] Adv. Synth. Catal. 2009, 351:423-431, reported a batch synthesis route for diisopropylbenzene using a silica-supported ionic liquid acid as a catalyst. The catalyst exhibited good selectivity for p-diisopropylbenzene and m-diisopropylbenzene. Although the conversion remained stable during the cyclic test, the change in selectivity indicated that the physicochemical properties of the catalyst had changed. Therefore, the stability of the catalyst still needs further investigation, and batch operation is not conducive to continuous industrial production. Micropor. Mesopor. Mater. 2008, 111:544-550, reported the alkylation reaction of cumene and 2-propanol catalyzed by acid-washed MOR. The proportion of p-diisopropylbenzene in diisopropylbenzene was less than 60%, and the effect of product water on the structural stability of the catalyst at 300 °C still needs further investigation. J. Catal. 1989, 120: 409-412 reported on the research of ZSM-12 catalytic alkylation of cumene and propylene to prepare diisopropylbenzene. The selectivity of the product to diisopropylbenzene was between 65% and 80%. The article lacked an investigation on the stability of the catalyst, and the selectivity of o-diisopropylbenzene was greater than 0.5%. Summary of the Invention
[0005] This invention modifies the surface acidity and pore structure of the catalyst by modifying the eutectic molecular sieve with elements, effectively reducing the selectivity of o-diisopropylbenzene. Combined with the modulation of the Beta and MOR ratio, the selectivity of diisopropylbenzene can be modulated between 30% and 78%, while the selectivity of o-diisopropylbenzene is less than 0.5%, thus solving the problem of uncontrollable diisopropylbenzene selectivity in single molecular sieve catalysts.
[0006] This invention provides a eutectic molecular sieve catalyst for the alkylation of cumene and propylene and its preparation method. The catalyst, prepared by adjusting the Beta and MOR ratio in the eutectic molecular sieve, elemental modification, and molding process, exhibits a selectivity for diisopropylbenzene that can be adjusted between 30% and 78% in the alkylation reaction of cumene and propylene, while maintaining a selectivity for o-diisopropylbenzene below 0.5%.
[0007] According to one aspect of this application, a method for preparing diisopropylbenzene is provided, comprising the following steps:
[0008] In a reactor, cumene and propylene are contacted with a catalyst and reacted to yield diisopropylbenzene;
[0009] The catalyst is obtained through the following steps:
[0010] The modified Beta&MOR eutectic molecular sieve, binder, extrusion aid and acid are mixed, kneaded, extruded into strips, aged, dried and calcined to obtain the catalyst;
[0011] The modified Beta&MOR eutectic molecular sieve has a silica-to-alumina ratio of 20–300.
[0012] The adhesive is selected from at least one of silica sol or alumina sol;
[0013] The extrusion aid is a mixture of guar gum powder and tetraethylammonium chloride, wherein the mass content of tetraethylammonium chloride is 5-20 wt%.
[0014] The acid is selected from at least one of a 5-12% dilute nitric acid solution or a 5-10% acetic acid solution.
[0015] The mass ratio of the modified Beta&MOR eutectic molecular sieve to the binder is 60-90:10-40;
[0016] The mass of the extrusion aid is 2 to 6 wt% of the total mass of the modified Beta&MOR eutectic molecular sieve and the binder;
[0017] The mass of the acid is 40–100 wt% of the total mass of the modified Beta&MOR eutectic molecular sieve and binder.
[0018] The aging temperature is 80–140°C;
[0019] The aging time is 5–24 hours;
[0020] The drying temperature is 90–120°C;
[0021] The drying time is 10–24 hours;
[0022] The roasting temperature is 400–550°C;
[0023] The roasting time is 2 to 10 hours.
[0024] The modified Beta&MOR eutectic molecular sieve is obtained through the following steps:
[0025] The Beta&MOR eutectic molecular sieve was immersed in a solvent solution containing a precursor of the modified element, aged, dried, and calcined to obtain the modified Beta&MOR eutectic molecular sieve.
[0026] In the Beta&MOR eutectic molecular sieve, the mass content of Beta molecular sieve is 20-95 wt%.
[0027] The modified element precursor is selected from tetraethyl orthosilicate, and the phosphorus source is selected from at least one of phosphoric acid, diammonium hydrogen phosphate, ammonium dihydrogen phosphate, ammonium phosphate, magnesium nitrate, magnesium chloride, ferric nitrate, ferric chloride, lanthanum nitrate, lanthanum chloride, cerium nitrate, and cerium chloride.
[0028] The solvent is selected from at least one of water, cyclohexane, or ethanol;
[0029] The mass ratio of the modified element precursor to the Beta&MOR eutectic molecular sieve is 0.6–1.2:1;
[0030] The aging temperature is 20–80°C;
[0031] The aging time is 5–24 hours;
[0032] The drying temperature is 80–150°C;
[0033] The drying time is 10–24 hours;
[0034] The calcination temperature is 400–600°C;
[0035] The calcination time is 2 to 24 hours.
[0036] The modifying element accounts for 0.01 to 7% of the mass of the modified Beta&MOR eutectic molecular sieve.
[0037] The reaction temperature is 120–200°C;
[0038] The reaction is carried out at a pressure of 2–4 MPa.
[0039] The molar ratio of cumene to propylene is 1 to 10;
[0040] The mass hourly space velocity (MSV) of the propylene is 0.1–1.00 h⁻¹. -1 .
[0041] The beneficial effects that this application can produce include:
[0042] This invention provides a catalyst for the synthesis of diisopropylbenzene and its application. Using a modified Beta&MOR eutectic molecular sieve as the active component, wherein the SiO2 / Al2O3 ratio of the molecular sieve is in the range of 20–300, selective synthesis of m-diisopropylbenzene and p-diisopropylbenzene can be achieved. The selectivity for p-diisopropylbenzene can be tuned between 30–78%, while maintaining the selectivity for o-diisopropylbenzene below 0.5%. The elemental modification treatment of the eutectic molecular sieve can modulate the pore size and the acidity of the zeolite's outer surface, which is crucial for product selectivity control. Detailed Implementation
[0043] The present application is described in detail below with reference to the embodiments, but the present application is not limited to these embodiments.
[0044] Unless otherwise specified, all raw materials used in the embodiments of this application were purchased through commercial channels.
[0045] This application uses a flame ionization detector (FID) to analyze hydrocarbon products;
[0046] The conversion rate and selectivity calculation formulas in the embodiments of this application are as follows:
[0047] Cumene conversion rate = (inlet cumene - outlet cumene) / inlet cumene × 100% Eq.(1)
[0048] Product selectivity = Hydrocarbon A / Detected hydrocarbon products × 100% Eq.(2)
[0049] Example 1
[0050] 2.0 g ammonium phosphate, 2.0 g ferric nitrate, and 3.0 g cerium nitrate were dissolved in 54.5 g water, and then added dropwise to 80.0 g of Beta & MOR eutectic molecular sieve (Beta accounted for 89.5% of the eutectic molecular sieve). The mixture was stirred until homogeneous, aged at 30 °C for 5 h, dried at 100 °C for 12 h, and calcined at 450 °C for 4 h to obtain a modified eutectic molecular sieve. Then, the modified molecular sieve, 40.0 g silica sol solution (SiO2 content 30 wt.%), 4.0 g extrusion aid (tetraethylammonium chloride accounting for 6% of the extrusion aid mass), and 68.0 g of 11% dilute nitric acid solution were kneaded, extruded into strips, cured at 120 °C for 5 h, and dried at 100 °C for 12 h. Finally, the temperature was increased to 500 °C at 1 °C / min and held for 3.5 h. A modified catalyst (A1) with a Beta content of 89.5% in the eutectic molecular sieve was obtained.
[0051] Example 2
[0052] 2.0 g ammonium phosphate, 4.0 g magnesium nitrate, and 4.0 g lanthanum nitrate were dissolved in 52.0 g water, and then added dropwise to 80.0 g of Beta & MOR eutectic molecular sieve (Beta accounted for 75.0% of the eutectic molecular sieve). The mixture was stirred until homogeneous, aged at 30 °C for 5 h, dried at 100 °C for 12 h, and calcined at 450 °C for 4 h to obtain a modified eutectic molecular sieve. Then, the modified molecular sieve, 40.0 g silica sol solution (SiO2 content 30 wt.%), 4.0 g extrusion aid (tetraethylammonium chloride accounted for 6% of the extrusion aid mass), and 65.0 g of 10% dilute nitric acid solution were mixed, extruded, cured at 120 °C for 5 h, and dried at 100 °C for 12 h. Finally, the temperature was increased to 500 °C at 1 °C / min and held for 3.5 h. A modified catalyst (A2) with Beta accounting for 75.0% of the eutectic molecular sieve was obtained.
[0053] Example 3
[0054] 3.0 g ammonium phosphate, 4.0 g tetraethyl orthosilicate, and 5.0 g cerium nitrate were dissolved in 50.0 g water, and then added dropwise to 80.0 g of Beta & MOR eutectic molecular sieve (Beta accounted for 54.7% of the eutectic molecular sieve). The mixture was stirred until homogeneous, aged at 30 °C for 5 h, dried at 100 °C for 12 h, and calcined at 450 °C for 4 h to obtain a modified eutectic molecular sieve. Then, the modified molecular sieve, 40.0 g silica sol solution (SiO2 content 30 wt.%), 4.0 g extrusion aid (tetraethylammonium chloride accounting for 6% of the extrusion aid mass), and 62.0 g of 10% dilute nitric acid solution were mixed, extruded, cured at 120 °C for 5 h, and dried at 100 °C for 12 h. Finally, the temperature was increased to 500 °C at 1 °C / min and held for 3.5 h. A modified catalyst (A3) with a Beta content of 54.7% in the eutectic molecular sieve was obtained.
[0055] Example 4
[0056] 4.0 g ammonium phosphate, 5.0 g magnesium nitrate, and 6.0 g cerium nitrate were dissolved in 50.0 g water, and then added dropwise to 80.0 g of Beta & MOR eutectic molecular sieve (Beta accounted for 34.6% of the eutectic molecular sieve). The mixture was stirred until homogeneous, aged at 30 °C for 5 h, dried at 100 °C for 12 h, and calcined at 450 °C for 4 h to obtain a modified eutectic molecular sieve. The modified molecular sieve, 40.0 g silica sol solution (SiO2 content 30 wt.%), 4.0 g extrusion aid (tetraethylammonium chloride accounting for 6% of the extrusion aid mass), and 62.0 g of 10% dilute nitric acid solution were then mixed, extruded, cured at 120 °C for 5 h, and dried at 100 °C for 12 h. The temperature was then increased to 500 °C at 1 °C / min and held for 3.5 h. A modified catalyst (A4) with Beta accounting for 34.6% of the eutectic molecular sieve was obtained.
[0057] Example 5
[0058] 5.0 g ammonium phosphate, 6.0 g magnesium nitrate, and 7.0 g lanthanum nitrate were dissolved in 50.0 g water, and then added dropwise to 80.0 g of Beta & MOR eutectic molecular sieve (Beta accounted for 22.5% of the eutectic molecular sieve). The mixture was stirred until homogeneous, aged at 30 °C for 5 h, dried at 100 °C for 12 h, and calcined at 450 °C for 4 h to obtain a modified eutectic molecular sieve. Then, the modified molecular sieve, 40.0 g silica sol solution (SiO2 content 30 wt.%), 4.0 g extrusion aid (tetraethylammonium chloride accounted for 6% of the mass of the extrusion aid), and 62.0 g of 10% dilute nitric acid solution were mixed, extruded, cured at 120 °C for 5 h, and dried at 100 °C for 12 h. Finally, the temperature was increased to 500 °C at 1 °C / min and held for 3.5 h. A modified catalyst (A5) with a Beta content of 22.5% in the eutectic molecular sieve was obtained.
[0059] Comparative Example 1
[0060] 80.0 g of unmodified Beta & MOR eutectic molecular sieve (Beta accounts for 75.0% of the eutectic molecular sieve), 40.0 g of silica sol solution (SiO2 content of 30 wt.%), 4.0 g of extrusion aid (tetraethylammonium chloride accounts for 6% of the mass of the extrusion aid), and 65.0 g of 10% dilute nitric acid solution were mixed, extruded, cured at 120℃ for 5 h, and dried at 100℃ for 12 h; then, the temperature was increased to 500℃ at 1℃ / min and held for 3.5 h. A catalyst (B1) with Beta accounting for 75% of the eutectic molecular sieve content was obtained.
[0061] Compared with A2, B1 has higher selectivity for o-diisopropylbenzene and lower selectivity for p-diisopropylbenzene, indicating that elemental modification can reduce the acidity of the outer surface of the molecular sieve and reduce the selectivity for o-diisopropylbenzene; at the same time, it can reduce the pore size and modulate the ratio of p-diisopropylbenzene to m-diisopropylbenzene.
[0062] Test case
[0063] 3.0 g of the catalyst prepared by the above method was loaded into a fixed-bed reactor, and then cumene and propylene were introduced. The reactor was operated at 140 °C, 3.0 MPa, cumene / propylene ratio = 4, and propylene mass hourly space velocity = 0.2 h⁻¹. -1 The reaction was carried out under the specified conditions, and the results after 24 hours of reaction are listed in Table 1.
[0064] Table 1 shows the reactivity and selectivity of the catalysts in each example.
[0065] Table 1
[0066]
[0067]
[0068] The above description is merely a few embodiments of this application and is not intended to limit this application in any way. Although this application discloses preferred embodiments as described above, it is not intended to limit this application. Any changes or modifications made by those skilled in the art without departing from the scope of the technical solution of this application using the disclosed technical content are equivalent to equivalent implementation cases and fall within the scope of the technical solution.
Claims
1. A method for preparing diisopropylbenzene, characterized in that, Includes the following steps: In a reactor, cumene and propylene are contacted with a catalyst and reacted to yield diisopropylbenzene; The catalyst is obtained through the following steps: The modified Beta&MOR eutectic molecular sieve, binder, extrusion aid and acid are mixed, kneaded, extruded into strips, aged, dried and calcined to obtain the catalyst; The modified Beta&MOR eutectic molecular sieve has a silica-to-alumina ratio of 20–300.
2. The method according to claim 1, characterized in that, The adhesive is selected from at least one of silica sol or alumina sol; The extrusion aid is a mixture of guar gum powder and tetraethylammonium chloride, wherein the mass content of tetraethylammonium chloride is 5-20 wt%. The acid is selected from at least one of a 5-12% dilute nitric acid solution or a 5-10% acetic acid solution.
3. The method according to claim 1, characterized in that, The mass ratio of the modified Beta&MOR eutectic molecular sieve to the binder is 60-90:10-40; The mass of the extrusion aid is 2 to 6 wt% of the total mass of the modified Beta&MOR eutectic molecular sieve and the binder; The mass of the acid is 40–100 wt% of the total mass of the modified Beta&MOR eutectic molecular sieve and binder.
4. The method according to claim 1, characterized in that, The aging temperature is 80–140°C; The aging time is 5–24 hours; The drying temperature is 90–120°C; The drying time is 10–24 hours; The roasting temperature is 400–550°C; The roasting time is 2 to 10 hours.
5. The method according to claim 1, characterized in that, The modified Beta&MOR eutectic molecular sieve is obtained through the following steps: The Beta&MOR eutectic molecular sieve was immersed in a solvent solution containing a precursor of the modified element, aged, dried, and calcined to obtain the modified Beta&MOR eutectic molecular sieve.
6. The method according to claim 5, characterized in that, In the Beta&MOR eutectic molecular sieve, the mass content of Beta molecular sieve is 20-95 wt%. The modified element precursor is selected from tetraethyl orthosilicate, and the phosphorus source is selected from at least one of phosphoric acid, diammonium hydrogen phosphate, ammonium dihydrogen phosphate, ammonium phosphate, magnesium nitrate, magnesium chloride, ferric nitrate, ferric chloride, lanthanum nitrate, lanthanum chloride, cerium nitrate, and cerium chloride. The solvent is selected from at least one of water, cyclohexane, or ethanol; The mass ratio of the modified element precursor to the Beta&MOR eutectic molecular sieve is 0.6–1.2:1; The aging temperature is 20–80°C; The aging time is 5–24 hours; The drying temperature is 80–150°C; The drying time is 10–24 hours; The calcination temperature is 400–600°C; The calcination time is 2 to 24 hours.
7. The method according to claim 1, characterized in that, The reaction temperature is 120–200°C; The reaction is carried out at a pressure of 2–4 MPa.
8. The method according to claim 1, characterized in that, The molar ratio of cumene to propylene is 1 to 10; The mass hourly space velocity (MSV) of the propylene is 0.1–1.00 h⁻¹. -1 .