Process for the preparation of alkylbenzenes

Abstract

The application provides a preparation method of alkylbenzene, comprising: performing alkylation reaction of benzene and an olefin raw material under the action of a solid acid catalyst to obtain alkylbenzene; wherein the olefin raw material comprises long-chain olefin with carbon number not less than 6, the solid acid catalyst comprises a binder and a low-layer molecular sieve with MWW topology structure, the axial direction of the crystal band axis of the low-layer molecular sieve with MWW topology structure is the c-axis direction, the thickness of the low-layer molecular sieve with MWW topology structure along the c-axis direction is 1.5 nm to 25 nm, and the maximum length of the low-layer molecular sieve with MWW topology structure in the plane perpendicular to the c-axis direction is 200 nm to 3000 nm. The application has the advantages of long single-pass life of the catalyst, high raw material conversion rate, high selectivity of 2-alkylbenzene and 3-alkylbenzene, and low cost, and is beneficial to industrial application.

Description

Technical Field

[0001] This invention relates to a method for preparing alkylbenzene, belonging to the field of alkylbenzene production. Background Technology

[0002] Alkylation is a crucial reaction in petrochemicals. Commonly used catalysts can be categorized into Levitra (L) acid catalysts and Beta acid catalysts. Levitra catalysts, primarily represented by anhydrous AlCl3, offer advantages such as low cost, good catalytic activity, and mature technology. However, the production process generates large amounts of aluminum-containing waste liquid and results in numerous side reactions, leading to its near obsolescence in the market. Beta acid catalysts are represented by HF, H2SO4, and H3PO4. Currently, the industrial production of linear alkylbenzene (LAB) mainly utilizes HF catalysts, which feature high catalytic activity and mature technology. However, due to the strong corrosiveness of HF acid, the equipment requirements are extremely high. In particular, the contact parts with HF acid are made of expensive Monel alloy, resulting in substantial construction and maintenance costs. Furthermore, the production process also generates various wastes, leading to high environmental costs.

[0003] In the 1980s, UOP developed the Detal solid acid alkylation technology, replacing the traditional HF catalyst with a solid acid catalyst. This fundamentally solved the problems of equipment corrosion and environmental pollution caused by HF catalysts. The reduced requirements for equipment materials also lowered investment costs. Furthermore, the selectivity of target products such as 2-alkylbenzene was improved to some extent compared to the HF catalytic process. Given these advantages of solid acid catalytic alkylation, it has gradually become a research hotspot in the catalytic synthesis of alkylbenzenes. For example, Han Minghan et al. (Applied Catalysis A, General. 2003, 99-107.) developed a catalyst with β-zeolite as the main active component, which can catalyze the synthesis of alkylbenzene products such as 2-alkylbenzene; however, the single-pass lifetime of this catalyst is less than 20 hours. Patent document CN101058523A discloses a method for preparing straight-chain alkylbenzenes, using straight-chain olefins with 2-20 carbon atoms and benzene as raw materials, employing a solid acid catalyst, and carrying out an alkylation reaction under supercritical conditions of 290-450℃ and 5-15 MPa to obtain straight-chain alkylbenzenes. The acid catalyst is a composite solid acid catalyst obtained by supporting and modifying one of the following: SBA-15 molecular sieve, HY molecular sieve, USY molecular sieve, Hβ molecular sieve, H-Moderite molecular sieve, HZSM-20 molecular sieve. This preparation process suffers from drawbacks such as harsh reaction conditions, high energy consumption, demanding equipment requirements, and high cost. Patent document CN103079698A discloses a method for controlling the 2-phenyl isomer content of linear alkylbenzenes and the catalyst used in the method. The method includes: making... The reaction of basic linear olefins with aryl compounds under alkylation conditions in the presence of a catalyst, wherein the linear olefins comprise molecules having 8-28 carbon atoms, and the catalyst comprises a first catalyst component zeolite selected from rare earth element-containing octahedral zeolites and mixtures thereof, and a second catalyst component zeolite selected from UZM-8, zeolite MWW, zeolite BEA, zeolite OFF, zeolite MOR, zeolite LTL, zeolite MTW, BPH / UZM-4, and mixtures thereof. This process requires the introduction of rare earth elements into the catalyst, resulting in a complex catalyst composition; patent literature CN 108569945A discloses a method for producing linear alkylbenzene, comprising the step of contacting a long-chain olefin and benzene with a catalyst under alkylation reaction conditions. The catalyst comprises, by weight, 40-90 parts of organosilicon zeolite and 10-60 parts of binder. The organosilicon zeolite is required to have the following molar relationship: (1 / n)Al₂O₃:SiO₂:(m / n)R, where n = 5-250, m = 0.01-50, and R is at least one of alkyl, alkenyl, or phenyl. 29 The NMR solid-state NMR spectrum contains at least one Si in the range of -80 to +50 ppm. 29Nuclear magnetic resonance (NMR) peaks; the X-ray diffraction pattern of the zeolite shows d-interval maximum values ​​at 12.4±0.2, 10.5±0.3, 9.3±0.3, 6.8±0.2, 6.1±0.2, 5.5±0.2, 4.4±0.2, 4.0±0.2, 3.5±0.1, 3.4±0.1, and 3.3±0.1 Å. This process uses a specific structured organosilicon zeolite as the catalyst active host and requires the introduction of fluorine for fluorine modification to ensure its stability and other properties; patent. Document CN112705252A discloses a liquid-phase alkylation catalyst, its preparation method and application, and a method for the liquid-phase alkylation reaction of benzene and ethylene. The liquid-phase alkylation catalyst comprises a molecular sieve with a MWW topology and a binder. The content of the molecular sieve with the MWW topology is 50–90% by weight, and the content of the binder is 10–50% by weight, based on the total weight of the liquid-phase alkylation catalyst. The external surface area and pore volume of the liquid-phase alkylation catalyst are 0.45–0.65 cm³. 3 / g, In addition, a boron source needs to be introduced in the preparation of molecular sieves with MWW topology. It is actually a liquid-phase alkylation catalyst formed by the combination of boron-containing MWW molecular sieve and binder, which is used for the alkylation reaction of benzene and short-chain olefin (ethylene).

[0004] Although there have been reports on the synthesis of alkylbenzenes using solid acid catalysis, the efficiency of alkylbenzene preparation still needs to be further improved, especially when using long-chain olefins as raw materials. Due to the larger size of long-chain olefin molecules, they are more likely to clog catalyst channels, leading to catalyst deactivation and other problems. Improving catalyst single-pass life, feed conversion rate, selectivity of 2-alkylbenzene and 3-alkylbenzene in alkylation products, and reducing costs are still important issues for those skilled in the art. Summary of the Invention

[0005] This invention provides a method for preparing alkylbenzene, which has the advantages of long catalyst single-pass life, high raw material conversion rate, high selectivity for 2-alkylbenzene and 3-alkylbenzene, and low cost, and can effectively overcome the defects of the prior art.

[0006] In one aspect, the present invention provides a method for preparing alkylbenzene, comprising: alkylating benzene with an olefin feedstock in the presence of a solid acid catalyst to obtain alkylbenzene; wherein the olefin feedstock comprises a long-chain olefin having at least 6 carbon atoms, the solid acid catalyst comprises a binder and a low-layer molecular sieve having a MWW topology, the zone axis of the low-layer molecular sieve having the MWW topology is oriented along the c-axis, the thickness of the low-layer molecular sieve having the MWW topology along the c-axis is 1.5 nm to 25 nm, and the maximum length of the low-layer molecular sieve having the MWW topology in a plane perpendicular to the c-axis is 200 nm to 3000 nm.

[0007] According to one embodiment of the present invention, the low-layer molecular sieve with MWW topology is prepared by a process comprising the following steps: (I) mixing an alkali source, an aluminum source, a template agent, a silicon source and water to prepare a crystallized gel; (II) subjecting the crystallized gel to primary crystallization at a temperature of T1 to obtain a primary crystallized product; wherein T1 is 120℃~180℃, and the primary crystallization time is 12h~36h; (III) subjecting the primary crystallized product to secondary crystallization at a temperature of T2 to obtain a secondary crystallized product; wherein T2=T1-T3, 0<T3≤50℃, and the secondary crystallization time is t, 0<t≤60h; (IV) cooling the secondary crystallized product to room temperature, adding a quaternary ammonium salt and a silicon agent, and stirring in a sealed environment at 50℃~85℃ for 3h~36h, and then subjecting the obtained product to drying, primary calcination, ammonium exchange, and secondary calcination in sequence to obtain the low-layer molecular sieve with MWW topology.

[0008] According to one embodiment of the present invention, the silicon source is SiO2, the aluminum source is Al2O3, the alkali source is a metal oxide, the molar ratio of the silicon source to the aluminum source is (22.5-97.5):1, the molar ratio of the template agent to the silicon source is (0.08-0.45):1, the molar ratio of the alkali source to the silicon source is (0.03-0.20):1, and the molar ratio of water to the silicon source is (10-60):1.

[0009] According to one embodiment of the present invention, the silicon source is SiO2, the quaternary ammonium salt is quaternary ammonium cation, the silicon agent is SiO2, the molar ratio of the quaternary ammonium salt to the silicon source is (0.1~1.0):1, and the molar ratio of the silicon agent to the silicon source is (0.05~2.5):1.

[0010] According to one embodiment of the present invention, the silicon source comprises silica sol and / or solid silica gel; and / or, the aluminum source comprises sodium aluminate and / or aluminum sulfate; and / or, the template agent comprises hexamethyleneimine or a mixture of hexamethyleneimine and cyclohexylamine; and / or, the alkali source comprises sodium hydroxide and / or potassium hydroxide; and / or, the quaternary ammonium salt comprises at least one of tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrapropylammonium hydroxide, tetrabutylammonium hydroxide, tetramethylammonium bromide, tetraethylammonium bromide, tetrapropylammonium bromide, tetrabutylammonium bromide, tetramethylammonium chloride, tetraethylammonium chloride, tetrapropylammonium chloride, and tetrabutylammonium chloride; and / or, the silicon agent comprises silica sol and / or tetraethyl orthosilicate.

[0011] According to one embodiment of the present invention, the process of preparing the crystallized gel includes: dissolving an alkali source and an aluminum source in water, stirring for 0 to 3 hours, adding a template agent, stirring for 0 to 24 hours, adding a silicon source, and stirring for 0 to 3 hours to obtain the crystallized gel.

[0012] According to one embodiment of the present invention, the first calcination process includes: calcining the product at 350°C to 400°C for 3 to 7 hours in an inert atmosphere, and then calcining it at 500°C to 600°C for 3 to 7 hours in an oxygen-containing gas atmosphere.

[0013] According to one embodiment of the present invention, the ammonium exchange is carried out using an ammonium salt solution, wherein the ammonium salt includes ammonium nitrate, and the temperature of the ammonium exchange is 70°C to 90°C.

[0014] According to one embodiment of the present invention, the temperature of the secondary roasting is 500℃~600℃, and the time of the secondary roasting is 2h~6h.

[0015] According to one embodiment of the present invention, in the low-layer molecular sieve with MWW topology, the molar ratio of silicon to aluminum, calculated as SiO2 and Al2O3, is (19-75):1.

[0016] According to one embodiment of the present invention, the solid acid catalyst is prepared by a process comprising the following steps: mixing the low-layer molecular sieve having the MWW topology with a binder, adding an inorganic acid and water thereto, molding and drying in sequence, and then calcining at 500°C to 600°C for 4 to 8 hours to obtain the solid acid catalyst.

[0017] According to one embodiment of the present invention, in the solid acid catalyst, the mass percentage of the low-layer molecular sieve having the MWW topology is 10% to 95%, and the remainder is a binder.

[0018] According to one embodiment of the present invention, the binder includes at least one of aluminum oxide, boehmite, boehmite, and aluminum hydroxide.

[0019] According to one embodiment of the present invention, the long-chain olefin includes linear olefins with a carbon number of 6 to 22.

[0020] According to one embodiment of the present invention, the molar ratio of benzene to the long-chain olefin is (5-50):1.

[0021] According to one embodiment of the present invention, the alkylation reaction conditions are: a temperature of 100°C to 200°C, a pressure of 1 MPa to 7 MPa, and a mass hourly space velocity (HHSV) of the mixture of benzene and the long-chain olefin of 0.5 h⁻¹. -1 ~12h -1 .

[0022] In this invention, a low-layer molecular sieve with a specific MWW topology is used as a solid acid catalyst, which can efficiently catalyze the alkylation of benzene and long-chain olefins, improving the conversion rate of long-chain olefins and the selectivity of 2-alkylbenzene and 3-alkylbenzene in the alkylation products. Simultaneously, the catalyst has a long single-pass lifetime; studies show that the catalyst's single-pass lifetime can reach over 220 hours, even over 500 hours, with a long-chain olefin conversion rate of over 99%, a 2-alkylbenzene selectivity of over 42%, and a 2-alkylbenzene and 3-alkylbenzene selectivity of over 63%. Furthermore, the catalyst used in this invention has a simple composition, does not require the introduction of halogens, fluorine, boron, or other elements, is low in cost, and also has the advantages of mild alkylation reaction conditions and high efficiency, making it suitable for industrial application. Attached Figure Description

[0023] Figure 1 The X-ray diffraction (XRD) pattern of the H-type molecular sieve prepared in Example 1 (the horizontal axis is the 2θ angle, and the vertical axis is the peak intensity).

[0024] Figure 2 The image shows a scanning electron microscope (SEM) image of the H-type molecular sieve prepared in Example 1.

[0025] Figure 3 The XRD pattern of the H-type molecular sieve prepared in Example 2;

[0026] Figure 4 Here is a SEM image of the H-type molecular sieve prepared in Example 2;

[0027] Figure 5 The XRD pattern of the H-type β-zeolite molecular sieve used in Comparative Example 1 is shown.

[0028] Figure 6 SEM image of the H-type β-zeolite molecular sieve used in Comparative Example 1.

[0029] Figure 7 The XRD pattern of the H-type MWW structured zeolite molecular sieve used in Comparative Example 2 is shown.

[0030] Figure 8 SEM image of the H-type MWW structured zeolite molecular sieve used in Comparative Example 2;

[0031] Figure 9 The image shows the SEM image of the H-type molecular sieve prepared in Comparative Example 3. Detailed Implementation

[0032] To enable those skilled in the art to better understand the present invention, the present invention will be further described in detail below. The specific embodiments listed below are merely descriptions of the principles and features of the present invention, and the examples are only for explaining the present invention and are not intended to limit the scope of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0033] The present invention provides a method for preparing alkylbenzene, comprising: alkylating benzene with an olefin feedstock under the action of a solid acid catalyst to obtain alkylbenzene; wherein the olefin feedstock includes a long-chain olefin with not less than 6 carbon atoms, the solid acid catalyst comprises a binder and a low-layer molecular sieve with a MWW topology, the zone axis of the low-layer molecular sieve with the MWW topology is oriented along the c-axis, the thickness of the low-layer molecular sieve with the MWW topology along the c-axis is 1.5 nm to 25 nm, and the maximum length of the low-layer molecular sieve with the MWW topology in a plane perpendicular to the c-axis is 200 nm to 3000 nm.

[0034] In this invention, the thickness of the low-layer molecular sieve with MWW topology along the c-axis and its maximum length (or dimension) in a plane perpendicular to the c-axis can be measured by electron microscopy (SEM). Specifically, the a-axis, b-axis, and c-axis are mutually perpendicular to form a spatial rectangular coordinate system. The axial direction of the zone axis of the low-layer molecular sieve is the c-axis direction, and its thickness in the c-axis direction (i.e., the axial direction of its zone axis) is 1.5nm to 25nm, for example, 1.5nm, 3nm, 5nm, 10nm, 15nm, 20nm, 25nm, or any two of these ranges. The plane where the a-axis and b-axis are located is a plane perpendicular to the c-axis direction. The size (i.e., the maximum length) of the low-layer molecular sieve in this plane is 200nm to 3000nm, for example, 200nm, 500nm, 800nm, 1000nm, 1200nm, 1500nm, 1800nm, 2000nm, 2200nm, 2500nm, 2800nm, 3000nm, or any two of these ranges.

[0035] In this invention, the above-mentioned low-layer molecular sieve with MWW topology is prepared by the following steps: (I) mixing an alkali source, an aluminum source, a template agent, a silicon source, and water to obtain a crystallized gel; (II) subjecting the crystallized gel to primary crystallization at a temperature of T1 to obtain a primary crystallized product; wherein T1 is 120℃~180℃, and the primary crystallization time is 12h~36h; (III) subjecting the primary crystallized product to secondary crystallization at a temperature of T2 to obtain a secondary crystallized product; wherein T2=T1-T3, 0<T3≤50℃, and the secondary crystallization time is t, 0<t≤60h; (IV) cooling the secondary crystallized product to room temperature, adding a quaternary ammonium salt (or quaternary ammonium base) and a silicon agent, and stirring in a sealed environment at 50℃~85℃ for 3h~36h, and then sequentially filtering, drying, primary calcination, ammonium exchange, and secondary calcination to obtain a low-layer molecular sieve with MWW topology.

[0036] Generally, when using solid acid catalysts to catalyze the alkylation of benzene with long-chain olefins, large molecules such as long-chain olefins, long-chain byproducts, and polycyclic aromatic hydrocarbon byproducts generated during the reaction easily clog the catalyst channels, leading to catalyst deactivation. Macroporous twelve-membered ring molecular sieves possess strong internal diffusion properties, which can alleviate the problem of rapid catalyst deactivation caused by channel blockage to some extent. However, traditional twelve-membered ring macroporous molecular sieves (such as octahedral zeolite and beta zeolite) are still easily deactivated by macromolecules clogging the internal channels of the crystal. Although existing technologies have solid acid catalysts using different types of twelve-membered ring macroporous molecular sieves as the main active component, these usually require the introduction of elements such as halogens to modify the molecular sieve to ensure its diffusion performance. This results in problems such as cumbersome catalyst preparation costs, the presence of highly corrosive halogens, and reduced molecular sieve stability.

[0037] In this invention, through the above-described molecular sieve preparation process, a molecular sieve with a suitable structure and composition and a MWW topology can be obtained. This sieve, when combined with a binder, forms a solid acid catalyst that can efficiently catalyze the alkylation reaction of benzene and long-chain olefins, improving the conversion rate of long-chain olefins and the selectivity of target products such as 2-alkylbenzene and 3-alkylbenzene. Furthermore, this solid acid catalyst also has advantages such as a long single-pass lifetime. The inventors, through research and analysis, believe that the low-layer molecular sieve without an MWW topology obtained through the above process has a special lamellar molecular sieve morphology. Its surface-distributed semi-hypercage structure has a good diffusion effect on macromolecules such as long-chain olefins and can increase the exposure degree of active catalytic sites (acidic sites) in a unit mass of solid acid catalyst. This results in a longer single-pass lifetime and excellent catalytic activity, achieving efficient alkylation of benzene and long-chain olefins. In addition, the above process does not require the introduction of halogens (such as fluorine) to modify the molecular sieve and also has advantages such as simple catalyst composition, simple preparation process, low cost, good stability, and excellent regeneration performance, which is conducive to industrial implementation.

[0038] In some embodiments, the silicon source is SiO2, the aluminum source is Al2O3, and the alkali source is a metal oxide (e.g., M2O when the alkali source is an alkali metal (M) hydroxide (MOH). The molar ratio of the silicon source to the aluminum source is (22.5–97.5):1, for example, 22.5:1, 25:1, 30:1, 35:1, 40:1, 45:1, 50:1, 55:1, 60:1, 65:1, 70:1, 75:1, 80:1, 85:1, 90:1, 95:1, 97.5:1, or any combination thereof. The molar ratio of the template agent to the silicon source is (0.08–0.45):1, for example, 0. The range of 0.8:1, 0.1:1, 0.15:1, 0.2:1, 0.25:1, 0.3:1, 0.35:1, 0.4:1, 0.45:1 or any two of these, with a molar ratio of alkali source to silicon source of (0.03 to 0.20):1, for example, 0.03:1, 0.05:1, 0.08:1, 0.1:1, 0.12:1, 0.15:1, 0.18:1, 0.2:1 or any two of these, and a molar ratio of water to silicon source of (10 to 60):1, for example, 10:1, 20:1, 30:1, 40:1, 50:1, 60:1 or any two of these.

[0039] In some embodiments, the silicon source is SiO2, and the quaternary ammonium salt is a quaternary ammonium cation (NR). +The silicon agent is calculated as SiO2, and the molar ratio of quaternary ammonium salt to silicon source is (0.1~1.0):1, for example, 0.1:1, 0.3:1, 0.5:1, 0.7:1, 1:1 or any two of these ranges. The molar ratio of silicon agent to silicon source is (0.05~2.5):1, for example, 0.05:1, 0.08:1, 0.1:1, 0.12:1, 0.15:1, 0.18:1, 0.2:1, 0.22:1, 0.25:1 or any two of these ranges.

[0040] In this invention, the aluminum source may include sodium aluminate and / or aluminum sulfate, specifically sodium aluminate, aluminum sulfate, or a mixture of sodium aluminate and aluminum sulfate.

[0041] In this invention, the alkali source used may specifically include inorganic alkalis, particularly soluble inorganic alkalis, such as hydroxides of alkali metals. In some specific embodiments, the alkali source includes sodium hydroxide and / or potassium hydroxide.

[0042] In this invention, the template agent used may specifically include an organic template agent, such as an organic amine template agent, and in particular, hexamethyleneimine. In some preferred embodiments, the template agent includes hexamethyleneimine or a mixture of hexamethyleneimine and cyclohexylamine.

[0043] In this invention, the silicon source used may specifically include an inorganic silicon source, which is advantageous for further cost savings compared to using an organic silicon source. Furthermore, according to the research of this invention, using an inorganic silicon source through the above-described molecular sieve preparation process can further improve the catalytic activity and lifespan of the solid acid catalyst for the alkylation of benzene and long-chain olefins. In some preferred embodiments, the silicon source includes silica sol and / or solid silica gel.

[0044] In this invention, the quaternary ammonium salt may include tetraalkylammonium hydroxide and / or tetraalkylammonium halide, wherein the tetraalkylammonium halide includes tetraalkylammonium bromide and / or tetraalkylammonium chloride, and the alkyl group may be a C1-C4 alkyl group, such as methyl, ethyl, propyl, butyl, etc. In some preferred embodiments, the above-mentioned quaternary ammonium salt includes at least one of tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrapropylammonium hydroxide, tetrabutylammonium hydroxide, tetramethylammonium bromide, tetraethylammonium bromide, tetrapropylammonium bromide, tetrabutylammonium bromide, tetramethylammonium chloride, tetraethylammonium chloride, tetrapropylammonium chloride, and tetrabutylammonium chloride.

[0045] In this invention, the silicone agent used may include organosilicon and / or inorganic silicon, such as tetraethyl orthosilicate, and silica sol. In some specific embodiments, the silicone agent includes silica sol and / or tetraethyl orthosilicate.

[0046] Specifically, in the above preparation process, after mixing the raw materials, two stages of crystallization are carried out at temperatures T1 and T2 respectively. The temperature T2 of the secondary crystallization is controlled to be T3 lower than that of the primary crystallization T1. That is, after the primary crystallization is completed, the temperature T3 of the primary crystallization in step (III) is reduced to allow the primary crystallization product to continue to crystallize. Combined with subsequent treatments such as adding quaternary ammonium salt and silicon agent followed by closed stirring, a low-layer molecular sieve with a suitable structure can be obtained. According to the research of this invention, after being compounded with a binder to form a solid acid catalyst, it can efficiently catalyze the alkylation reaction of benzene and long-chain olefins.

[0047] In some embodiments, the process of obtaining a crystallized gel includes: dissolving an alkali source and an aluminum source in water, stirring for 0 to 3 hours, for example, 0.5 hours, 1 hour, 1.5 hours, 2 hours, 2.5 hours, 3 hours or any combination thereof; then adding a template agent and stirring for 0 to 24 hours, for example, 0.5 hours, 1 hour, 3 hours, 5 hours, 7 hours, 10 hours, 12 hours, 15 hours, 18 hours, 20 hours or any combination thereof; then adding a silicon source and stirring for 0 to 3 hours, for example, 0.5 hours, 1 hour, 1.5 hours, 2 hours, 2.5 hours, 3 hours or any combination thereof, to obtain a crystallized gel.

[0048] Optionally, in step (II), T1 is a range of 120℃, 125℃, 130℃, 135℃, 140℃, 145℃, 150℃, 155℃, 160℃, 165℃, 170℃, 175℃, 180℃, or any combination thereof, and the single crystallization time is 12h, 15h, 18h, 20h, 22h, 25h, 28h, 30h, 33h, 36h, or a combination thereof. The range of any two of the following; in step (III), T3 is a range of 5℃, 10℃, 15℃, 20℃, 25℃, 30℃, 35℃, 40℃, 45℃, 50℃ or any two of these, and the secondary crystallization time t is a range of 5h, 10h, 15h, 20h, 25h, 30h, 35h, 40h, 45h, 50h, 55h, 60h or any two of these.

[0049] After the crystallization of the above two stages is completed, the resulting secondary crystallization product (crystallization mother liquor) is cooled to room temperature, and quaternary ammonium salt and silicon agent are added to it. Then, it is transferred to a closed mixer for closed stirring (or the crystallization mother liquor is transferred to a closed mixer before adding quaternary ammonium salt and silicon agent, followed by closed stirring). For example, the temperature for closed stirring is within the range of 50℃, 55℃, 60℃, 65℃, 70℃, 75℃, 80℃, 85℃, or any combination thereof, and the stirring time is within the range of 3h, 5h, 10h, 15h, 20h, 25h, 30h, 33h, 36h, or any combination thereof.

[0050] In the above preparation process, after the closed stirring is completed, the obtained product is washed with water and filtered in sequence, and then the obtained solid product is subjected to drying, primary calcination, ammonium exchange, and secondary calcination in sequence. The drying temperature can be 100℃~150℃, for example, 100℃, 110℃, 120℃, 130℃, 140℃, 150℃ or any combination thereof, and the drying time can be 3h~5h.

[0051] In some preferred embodiments, after a single calcination, the template agent is removed. The single calcination process includes: calcining the product (i.e., the dried product obtained after the above drying) at 350°C to 400°C (referred to as low-temperature calcination) for 3 to 7 hours in an inert atmosphere, followed by calcination at 500°C to 600°C (referred to as high-temperature calcination) for 3 to 7 hours in an oxygen-containing gas atmosphere. The inert atmosphere includes, for example, nitrogen, and the oxygen-containing gas includes oxygen. The low-temperature calcination temperature is, for example, a range of 350°C, 360°C, 370°C, 380°C, 390°C, 400°C, or any combination thereof. The calcination time is, for example, a range of 3h, 4h, 5h, 6h, 7h, or any combination thereof; the high-temperature calcination temperature is, for example, a range of 500℃, 510℃, 520℃, 530℃, 540℃, 550℃, 560℃, 570℃, 580℃, 590℃, 600℃, or any combination thereof; and the high-temperature calcination time is, 3h, 4h, 5h, 6h, 7h, or any combination thereof. Through this inert atmosphere low-temperature calcination and oxygen-containing gas high-temperature calcination process, the performance of the prepared solid acid catalyst can be optimized, further improving the alkylbenzene preparation efficiency.

[0052] The product after a single calcination is generally a sodium-type molecular sieve with a MWW topology. After treatment such as ammonium exchange, it can be converted into an H-type molecular sieve. In specific implementation, ammonium salt solution can be used for ammonium exchange. That is, the product after the high-temperature calcination is placed in an ammonium salt solution for ammonium exchange. After ammonium exchange, the ammonium exchange product is calcined a second time to obtain the H-type molecular sieve (i.e., the low-layer molecular sieve with the MWW topology mentioned above). The ammonium salt can include ammonium nitrate, and the ammonium salt solution can be an aqueous solution of ammonium salt. The ammonium exchange temperature can be 70℃~90℃, for example, 70℃, 75℃, 80℃, 85℃, 90℃ or any combination thereof, and the ammonium exchange time can generally be 1h~3h.

[0053] In some embodiments, the temperature of the secondary roasting can be 500℃ to 600℃, for example, a range of 500℃, 510℃, 520℃, 530℃, 540℃, 550℃, 560℃, 570℃, 580℃, 590℃, 600℃ or any two of these, and the time of the secondary roasting can be 2h to 6h, for example, a range of 2h, 3h, 4h, 5h, 6h or any two of these.

[0054] In this invention, the water used can be deionized water, but is not limited to this.

[0055] In this invention, the solid acid catalyst can be prepared by a process including the following steps: mixing a low-layer molecular sieve with an MWW topology with a binder, adding an inorganic acid and water, and then sequentially molding, drying, and calcining to obtain the solid acid catalyst; wherein the inorganic acid may include nitric acid, the molding can be extrusion molding, the drying can be air drying at 20℃~30℃ (room temperature), the calcination temperature can be 500℃~600℃, for example, 500℃, 510℃, 520℃, 530℃, 540℃, 550℃, 560℃, 570℃, 580℃, 590℃, 600℃ or any combination thereof, and the calcination time can be 4h~8h, for example, 4h, 5h, 6h, 7h, 8h or any combination thereof.

[0056] In some preferred embodiments, in the aforementioned low-layered molecular sieve with the MWW topology, the silicon-to-aluminum molar ratio, calculated as SiO2 and Al2O3, is (19–75):1. That is, the silicon-to-aluminum molar ratio in the chemical composition of the low-layered molecular sieve satisfies: SiO2:Al2O3 = (19–75):1, for example, 19:1, 25:1, 30:1, 35:1, 40:1, 45:1, 50:1, 55:1, 60:1, 65:1, 70:1, 75:1, or any combination thereof. In specific implementations, the silicon-to-aluminum ratio of the obtained low-layered molecular sieve can be adjusted according to the amount of the silicon source, aluminum source, and other raw materials used.

[0057] According to the research of the present invention, by controlling the content of low-layer cascade molecular sieves in the solid acid, the performance of the solid acid catalyst can be further optimized, and the alkylation efficiency of benzene and long-chain olefins can be improved. In some preferred embodiments, the mass percentage of low-layer cascade molecular sieves with MWW topology in the solid acid catalyst is 10% to 95%, for example, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, or any combination thereof, with the balance being a binder. Preferably, the content of low-layer cascade molecular sieves in the solid acid catalyst is higher than the content of binder, and more preferably, the content of low-layer cascade molecular sieves is 85% to 95%.

[0058] In this invention, the binder may include inorganic oxide binders, such as at least one of aluminum oxide, boehmite, gibbsite, and aluminum hydroxide.

[0059] In this invention, long-chain olefins may specifically include linear olefins with a carbon number of not less than 6, and generally preferably include linear olefins with a carbon number of 6 to 22. The number of carbons in the olefin molecules included in the long-chain olefins is, for example, a range of 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22 or any two of these. That is, long-chain olefins may include at least one of olefins with a carbon number of 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22. Preferably, the long-chain olefins include linear olefins with a carbon number of 8 to 18. In addition, the above-mentioned long-chain olefins can be long-chain α-linear olefins with terminal double bonds, wherein the number of C=C double bonds is generally one, such as at least one of 1-octene, 1-decene, 1-dodecene, 1-tetradecene, 1-hexadecene, and 1-octadecene.

[0060] In general, during the preparation of the above alkylbenzene, the molar ratio of benzene to long-chain olefin can be (5 to 50):1, for example, 5:1, 10:1, 15:1, 20:1, 25:1, 30:1, 35:1, 40:1, 45:1, 50:1 or any combination thereof.

[0061] In this invention, the alkylation reaction is specifically carried out in a reactor, which includes, for example, a fixed-bed reactor, but is not limited thereto. The conditions for the alkylation reaction can be: a temperature of 100°C to 200°C, for example, a range of 100°C, 120°C, 140°C, 160°C, 180°C, 200°C, or any combination thereof; a pressure of 1 MPa to 7 MPa, for example, a range of 1 MPa, 2 MPa, 3 MPa, 4 MPa, 5 MPa, 6 MPa, 7 MPa, or any combination thereof; and a mass hourly space velocity (HHSV) of 0.5 h⁻¹ for the mixture of benzene and long-chain olefins. -1 ~12h -1 For example, 0.5h -1 1h -1 2h -1 3h -1 4h -1 5h -1 6h -1 7h -1 8h -1 9h -1 10h -1 11h -1 12h -1 or a range consisting of any two of them.

[0062] In practice, a mixture of benzene and long-chain olefins can be introduced into a reactor. Inside the reactor, benzene, long-chain olefins, and a solid acid catalyst react, undergoing an alkylation reaction under the catalysis of the solid acid catalyst to produce alkylbenzenes. This alkylbenzene can specifically include linear alkylbenzenes. 2-alkylbenzenes and 3-alkylbenzenes, in particular, possess advantages such as good solubility, easy biodegradability, and environmental friendliness, making them important chemical products. The alkylbenzenes obtained through the above preparation process generally include 2-alkylbenzenes and 3-alkylbenzenes, and the yield of target products such as 2-alkylbenzenes and 3-alkylbenzenes can be improved.

[0063] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below in conjunction with specific embodiments. Obviously, the described embodiments are only some embodiments of this invention, not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0064] The specifications of the raw materials used in the following embodiments are as follows:

[0065] (1) Silicon source: silica sol (with a SiO2 mass content of 40%), solid silica gel (with a SiO2 mass content of 97%);

[0066] (2) Template agents: hexamethyleneimine (98% purity), cyclohexylamine (99% purity);

[0067] (3) Aluminum source: sodium aluminate (with an Al2O3 mass content of 41%), aluminum sulfate (with an Al2O3 mass content of 15%);

[0068] (4) Alkali source: Sodium hydroxide (99% purity), potassium hydroxide (99% purity);

[0069] (5) Other: Deionized water.

[0070] In the following examples, the selectivity of 2-alkylbenzene and 3-alkylbenzene was determined according to the following procedure: the peak area A of the alkylation product was determined by high performance liquid chromatography (HPLC). 总 (That is, the sum of the peak areas of all alkylbenzenes generated by the alkylation of benzene), determine the peak area A2 of 2-alkylbenzene and the peak area A3 of 3-alkylbenzene, then the selectivity of 2-alkylbenzene = A2 / A 总 The selectivity of 2-alkylbenzene + 3-alkylbenzene = (A2 + A3) / A 总 .

[0071] In the following examples, the conversion rate of long-chain olefins is (m0-m1) / m0, where m0 is the total number of moles of long-chain olefin feedstock and m1 is the number of moles of long-chain olefins remaining in the system after the alkylation reaction.

[0072] Example 1

[0073] (1) Preparation of low-density stratified molecular sieves with MWW topology

[0074] Add 36.5g of sodium hydroxide to 4000g of deionized water and stir to dissolve. Add 75g of sodium aluminate and stir to dissolve. Continue stirring vigorously for 1 hour. Then slowly add 352g of hexamethyleneimine and continue stirring vigorously for 0.5 hours. Then slowly add 1500g of silica sol and continue stirring vigorously for 3 hours to obtain crystallized gel.

[0075] The crystallized gel was crystallized at 160℃ (i.e., primary crystallization) for 36 h, and then cooled to 154℃ for further crystallization (i.e., secondary crystallization) for 24 h. After crystallization, the resulting crystallization mother liquor was cooled to room temperature, and 2750 g of tetrapropylammonium hydroxide solution (mass concentration of 25%) and 1230 g of tetraethyl orthosilicate were slowly added to it under continuous stirring. The mixture was then stirred in a water bath at 80℃ for 18 h. The resulting product was then washed and filtered with deionized water at 80℃, dried at 120℃ for 4 h, calcined at 375℃ for 5 h under a nitrogen atmosphere, and then calcined at 540℃ for 5 h under an oxygen atmosphere to obtain a low-layer sodium molecular sieve product with a MWW topology.

[0076] The above sodium-type molecular sieve product was placed in a 1 mol / L ammonium nitrate solution and subjected to ammonium exchange at 80 °C for 2 h. The resulting ammonium exchange product was then calcined at 550 °C for 4 h to obtain H-type molecular sieve.

[0077] The XRD pattern of this H-type molecular sieve was obtained through testing. Figure 1 SEM image (see) Figure 2 The H-type molecular sieve is a low-layer molecular sieve with an MWW topology, with a thickness of 5nm to 10nm along the c-axis and a maximum length of 500nm to 2000nm in a plane perpendicular to the c-axis.

[0078] (2) Preparation of solid acid catalysts

[0079] Mix 90g of the above-mentioned H-type molecular sieve with 15g of pseudoboehmite until homogeneous, and gradually add 55g of nitric acid solution while kneading. Extrude the mixture into strips. The cylindrical matrix was then cut into cylindrical intermediates with a length of 2.5 mm. The intermediates were air-dried at room temperature for 24 h and then calcined at 550 °C for 6 h to obtain solid acid catalyst B1.

[0080] (3) Alkylation reaction

[0081] Take 2g of the above solid acid catalyst B1 and load it into a fixed-bed reactor. Introduce a mixture of benzene and 1-dodecene into the reactor for alkylation to obtain alkylbenzene. The molar ratio of benzene to 1-dodecene is 15:1, the reaction temperature is 145℃, the reaction pressure is 4.0 MPa, and the mass hourly space velocity (HHSV) of the benzene and 1-dodecene mixture is 4.0 h⁻¹. -1 ;

[0082] After testing, the conversion rate of 1-dodecene was 99.65% after 500 hours of reaction, the selectivity of 2-alkylbenzene was 46.5%, and the selectivity of 2-alkylbenzene + 3-alkylbenzene was 67.3%.

[0083] Example 2

[0084] (1) Preparation of low-density stratified molecular sieves with MWW topology

[0085] Add 43.5g of sodium hydroxide to 3500g of deionized water and stir to dissolve. Add 48.3g of sodium aluminate and stir to dissolve. Continue stirring vigorously for 0.5h. Then slowly add 182g of hexamethyleneimine and 202g of cyclohexylamine and continue stirring vigorously for 1.5h. Finally, slowly add 1500g of silica sol and continue stirring vigorously for 5h to obtain a crystallized gel.

[0086] The crystallized gel was crystallized at 158℃ for 26 hours, then cooled to 148℃ and crystallized for another 20 hours. After crystallization, the resulting crystallization mother liquor was cooled to room temperature. Under continuous stirring, 725g of tetrapropylammonium bromide solid and 973g of tetraethyl orthosilicate were slowly added to it. The mixture was then stirred in a water bath at 80℃ for 10 hours. The resulting product was then washed and filtered with deionized water at 80℃, dried at 120℃ for 4 hours, calcined at 375℃ for 5 hours under a nitrogen atmosphere, and then calcined at 540℃ for 5 hours under an oxygen atmosphere to obtain a low-layer sodium molecular sieve product with a MWW topology.

[0087] The above sodium-type molecular sieve product was placed in a 1 mol / L ammonium nitrate solution and subjected to ammonium exchange at 80 °C for 2 h. The resulting ammonium exchange product was then calcined at 550 °C for 4 h to obtain H-type molecular sieve.

[0088] The XRD pattern of this H-type molecular sieve was obtained through testing. Figure 3 SEM image (see) Figure 4 It is a low-layer molecular sieve with an MWW topology, with a thickness of 15nm to 20nm along the c-axis and a maximum length of 500nm to 2000nm in a plane perpendicular to the c-axis.

[0089] (2) Preparation of solid acid catalysts

[0090] Mix 90g of the above-mentioned H-type molecular sieve with 9g of alumina until homogeneous, and gradually add 65g of nitric acid solution while kneading. Extrude the mixture into strips. The cylindrical matrix was then cut into cylindrical intermediates with a length of 2.5 mm. The intermediates were air-dried at room temperature for 24 h and then calcined at 550 °C for 6 h to obtain solid acid catalyst B2.

[0091] (3) Alkylation reaction

[0092] Take 2g of the above solid acid catalyst B2 and load it into a fixed-bed reactor. Introduce a mixture of benzene and 1-dodecene into the reactor for alkylation to obtain alkylbenzene. The molar ratio of benzene to 1-dodecene is 20:1, the reaction temperature is 140℃, the reaction pressure is 3.5MPa, and the mass hourly space velocity (HHSV) of the benzene and 1-dodecene mixture is 3.0 h⁻¹. -1 ;

[0093] After 220 hours of reaction, the conversion rate of 1-dodecene was 99.58%, the selectivity of 2-alkylbenzene was 43.7%, and the selectivity of 2-alkylbenzene + 3-alkylbenzene was 64.7%.

[0094] Example 3

[0095] Take 2g of the solid acid catalyst B1 prepared in Example 1, load it into a fixed-bed reactor, and introduce a mixture of benzene and 1-decene into the reactor for alkylation reaction to obtain alkylbenzene; wherein the molar ratio of benzene to 1-decene is 12:1, the reaction temperature is 138℃, the reaction pressure is 5.0MPa, and the mass hourly space velocity (HHSV) of the benzene and 1-decene mixture is 4.0h. -1 ;

[0096] After 320 hours of reaction, the conversion rate of 1-decene was 99.23%, the selectivity of 2-alkylbenzene was 48.3%, and the selectivity of 2-alkylbenzene + 3-alkylbenzene was 66.5%.

[0097] Example 4

[0098] Take 2g of the solid acid catalyst B1 prepared in Example 1, load it into a fixed-bed reactor, and introduce a mixture of benzene and 1-octene into the reactor for alkylation reaction to obtain alkylbenzene; wherein the molar ratio of benzene to 1-octene is 9:1, the reaction temperature is 139℃, the reaction pressure is 5.0MPa, and the mass hourly space velocity of the benzene and 1-octene mixture is 5.0h. -1 ;

[0099] After 350 hours of reaction, the conversion rate of 1-decene was 99.62%, the selectivity of 2-alkylbenzene was 42.2%, and the selectivity of 2-alkylbenzene + 3-alkylbenzene was 63.8%.

[0100] Example 5

[0101] Take 2g of the solid acid catalyst B2 prepared in Example 2, load it into a fixed-bed reactor, and introduce a mixture of benzene and 1-hexadecene into the reactor for alkylation reaction to obtain alkylbenzene; wherein the molar ratio of benzene to 1-hexadecene is 25:1, the reaction temperature is 148℃, the reaction pressure is 3.5MPa, and the mass hourly space velocity (HHSV) of the benzene and 1-hexadecene mixture is 3.0h. -1 ;

[0102] After 175 hours of reaction, the conversion rate of 1-hexadecene was 99.24%, the selectivity of 2-alkylbenzene was 48.1%, and the selectivity of 2-alkylbenzene + 3-alkylbenzene was 70.0%.

[0103] Example 6

[0104] Take 2g of the solid acid catalyst B2 prepared in Example 2, load it into a fixed-bed reactor, and introduce a mixture of benzene and 1-tetradecene into the reactor for alkylation reaction to obtain alkylbenzene; wherein the molar ratio of benzene to 1-tetradecene is 25:1, the reaction temperature is 144℃, the reaction pressure is 4.0MPa, and the mass hourly space velocity (HHSV) of the benzene and 1-tetradecene mixture is 3.0h. -1 ;

[0105] After 220 hours of reaction, the conversion rate of 1-tetradecene was 99.05%, the selectivity of 2-alkylbenzene was 47.2%, and the selectivity of 2-alkylbenzene + 3-alkylbenzene was 69.8%.

[0106] Example 7

[0107] Take 2g of the solid acid catalyst B2 prepared in Example 2, load it into a fixed-bed reactor, and introduce a mixture of benzene and 1-octadecene into the reactor for alkylation reaction to obtain alkylbenzene; wherein the molar ratio of benzene to 1-octadecene is 40:1, the reaction temperature is 154℃, the reaction pressure is 4.0MPa, and the mass hourly space velocity (HHSV) of the benzene and 1-octadecene mixture is 2.0h. -1 ;

[0108] After 160 hours of reaction, the conversion rate of 1-octadecene was 99.35%, the selectivity of 2-alkylbenzene was 50.2%, and the selectivity of 2-alkylbenzene + 3-alkylbenzene was 73.6%.

[0109] Comparative Example 1

[0110] The H-type molecular sieve prepared in Example 1 was replaced with a commercially available H-type β-zeolite molecular sieve, and the remaining conditions were the same as in step (2) of Example 1. Catalyst D1 was prepared according to step (2) of Example 1. The XRD pattern of the commercially available H-type β-zeolite molecular sieve is shown in [reference needed]. Figure 5 SEM image (see) Figure 6 ;

[0111] Take 2g of the above catalyst D1 and load it into a fixed-bed reactor. Introduce a mixture of benzene and 1-dodecene into the reactor to carry out an alkylation reaction to obtain alkylbenzene. The molar ratio of benzene to 1-dodecene is 15:1, the reaction temperature is 145℃, the reaction pressure is 4.0MPa, and the mass hourly space velocity of the benzene and 1-dodecene mixture is 4.0.

[0112] After 16 hours of reaction, the conversion rate of 1-dodecene was 97.32%, the selectivity of 2-alkylbenzene was 47%, and the selectivity of 2-alkylbenzene + 3-alkylbenzene was 63%.

[0113] As can be seen from Example 1 and Comparative Example 1, the solid acid catalyst B1 prepared in Example 1 has better catalytic activity, especially its single-pass lifetime is significantly higher than that of catalyst D1 in Comparative Example 1.

[0114] Comparative Example 2

[0115] The H-type molecular sieve prepared in Example 1 was replaced with a commercially available H-type MWW structure zeolite molecular sieve, and the remaining conditions were the same as in step (2) of Example 1. Catalyst D2 was prepared according to step (2) of Example 1. The XRD pattern of the commercially available H-type MWW structure zeolite molecular sieve is shown in [reference needed]. Figure 7 SEM image (see) Figure 8 Its thickness along the c-axis is more than 30 nm;

[0116] Take 2g of the above catalyst D2 and load it into a fixed-bed reactor. Introduce a mixture of benzene and 1-dodecene into the reactor for alkylation to obtain alkylbenzene. The molar ratio of benzene to 1-dodecene is 15:1, the reaction temperature is 145℃, the reaction pressure is 4.0 MPa, and the mass hourly space velocity (HHSV) of the benzene and 1-dodecene mixture is 4.0 h⁻¹. -1 ;

[0117] After testing, the conversion rate of 1-dodecene was 98.47% after 105 hours of reaction, the selectivity of 2-alkylbenzene was 41.9%, and the selectivity of 2-alkylbenzene + 3-alkylbenzene was 60.2%.

[0118] As can be seen from Example 1 and Comparative Example 1, the solid acid catalyst B1 prepared in Example 1 has better catalytic activity, especially its single-pass lifetime is significantly higher than that of catalyst D2 in Comparative Example 2. That is, the conventional MWW structure molecular sieve still has the problem of rapid catalyst deactivation, while the low-layer molecular sieve with MWW structure prepared by the specific preparation process of Example 1 can effectively solve this problem.

[0119] Comparative Example 3

[0120] (1) Preparation of molecular sieves

[0121] Add 36.5g of sodium hydroxide to 4000g of deionized water and stir to dissolve. Then add 75g of sodium aluminate and stir to dissolve. Continue stirring vigorously for 1 hour. Then slowly add 352g of hexamethyleneimine and stir vigorously for 0.5 hours. Then slowly add 1500g of silica sol and stir vigorously for 3 hours to obtain crystallized gel.

[0122] The crystallized gel was crystallized at 155℃ for 72 h. After crystallization, the crystallized product was cooled to room temperature, then washed, dried, and calcined at 540℃ for 5 h in an oxygen atmosphere to remove the template agent. It was then placed in a 1 mol / L ammonium nitrate solution and subjected to ammonium exchange at 80℃ for 2 h. The resulting ammonium exchange product was then calcined at 550℃ for 4 h to obtain an H-type molecular sieve. This H-type molecular sieve was identified as MCM-22 molecular sieve, and its SEM image is shown below. Figure 9 Its thickness along the c-axis is more than 30 nm;

[0123] (2) Preparation of solid acid catalysts

[0124] Mix 90g of the above-mentioned H-type molecular sieve with 15g of pseudoboehmite until homogeneous, and gradually add 55g of nitric acid solution while kneading. Extrude the mixture into strips. The cylindrical matrix was then cut into cylindrical intermediates with a length of 2.5 mm. The intermediates were air-dried at room temperature for 24 h and then calcined at 550 °C for 6 h to obtain catalyst D3.

[0125] (3) Alkylation reaction

[0126] Take 2g of the above catalyst D3 and load it into a fixed-bed reactor. Introduce a mixture of benzene and 1-dodecene into the reactor for alkylation to obtain alkylbenzene. The molar ratio of benzene to 1-dodecene is 15:1, the reaction temperature is 145℃, the reaction pressure is 4.0 MPa, and the mass hourly space velocity (HHSV) of the benzene and 1-dodecene mixture is 4.0 h⁻¹. -1 ;

[0127] After 150 hours of reaction, the conversion rate of 1-dodecene was 98.17%, the selectivity of 2-alkylbenzene was 41.2%, and the selectivity of 2-alkylbenzene + 3-alkylbenzene was 63.5%.

[0128] Compared with Example 1, no quaternary ammonium salt and silicon agent were added in Comparative Example 3. The synthesized molecular sieve was MCM-22 molecular sieve. The thickness of the molecular sieve along the c-axis was more than 30 nm. When the catalyst D3, which was formed by combining the molecular sieve and the binder, was used to catalyze the alkylation reaction of benzene and 1-dodecene, the catalyst deactivated after 150 h of reaction. The single-pass lifetime was much shorter than that of the solid acid catalyst B1 in Example 1.

[0129] The embodiments of the present invention have been described above. However, the present invention is not limited to the above embodiments. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for preparing alkylbenzene, characterized in that, include: Benzene and olefin feedstock are subjected to an alkylation reaction in the presence of a solid acid catalyst to obtain alkylbenzene; wherein the olefin feedstock includes long-chain olefins with no less than 6 carbon atoms, the solid acid catalyst comprises a binder and a low-layer molecular sieve with a MWW topology, the zone axis of the low-layer molecular sieve with the MWW topology is oriented along the c-axis, the thickness of the low-layer molecular sieve with the MWW topology along the c-axis is 1.5 nm to 25 nm, and the maximum length of the low-layer molecular sieve with the MWW topology in a plane perpendicular to the c-axis is 200 nm to 3000 nm; The low-density stacked molecular sieve with the MWW topology is prepared by a process including the following steps: (I) A crystallized gel is prepared by mixing an alkali source, an aluminum source, a template agent, a silicon source, and water; (II) The crystallized gel is subjected to a single crystallization at a temperature of T1 to obtain a single crystallized product; wherein, T1 is 120℃~180℃, and the single crystallization time is 12h~36h; (III) The primary crystallization product is subjected to secondary crystallization at a temperature of T2 to obtain a secondary crystallization product; wherein, T2=T1-T3, 0<T3≤50℃, and the secondary crystallization time is t, 0<t≤60h; (IV) The secondary crystallization product is cooled to room temperature, and quaternary ammonium salt and silicon agent are added to it. The mixture is then stirred in a closed container at 50℃~85℃ for 3h~36h. The resulting product is then dried, calcined once, exchanged with ammonium, and calcined twice in sequence to obtain the low-layer molecular sieve with MWW topology. The solid acid catalyst preparation process does not use halogens or boron to modify the molecular sieve.

2. The method for preparing alkylbenzene according to claim 1, characterized in that, The silicon source is calculated as SiO2, the aluminum source as Al2O3, and the alkali source as a metal oxide. The molar ratio of the silicon source to the aluminum source is (22.5~97.5):1, the molar ratio of the template agent to the silicon source is (0.08~0.45):1, the molar ratio of the alkali source to the silicon source is (0.03~0.20):1, and the molar ratio of water to the silicon source is (10~60):1; and / or, The silicon source is calculated as SiO2, the quaternary ammonium salt as quaternary ammonium cation, the silicon agent as SiO2, the molar ratio of the quaternary ammonium salt to the silicon source is (0.1~1.0):1, and the molar ratio of the silicon agent to the silicon source is (0.05~2.5):1; and / or, The silicon source includes silica sol and / or solid silica gel; and / or, The aluminum source includes sodium aluminate and / or aluminum sulfate; and / or, The template agent comprises hexamethyleneimine or a mixture of hexamethyleneimine and cyclohexylamine; and / or, The alkali source includes sodium hydroxide and / or potassium hydroxide; and / or, The quaternary ammonium salt comprises at least one of tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrapropylammonium hydroxide, tetrabutylammonium hydroxide, tetramethylammonium bromide, tetraethylammonium bromide, tetrapropylammonium bromide, tetrabutylammonium bromide, tetramethylammonium chloride, tetraethylammonium chloride, tetrapropylammonium chloride, and tetrabutylammonium chloride; and / or, The silicone agent includes silica sol and / or tetraethyl orthosilicate.

3. The method for preparing alkylbenzene according to claim 1, characterized in that, The process for preparing the crystallized gel includes: dissolving an alkali source and an aluminum source in water, stirring for 0-3 hours, adding a template agent, continuing to stir for 0-24 hours, adding a silicon source, and continuing to stir for 0-3 hours to obtain the crystallized gel; and / or, The single calcination process includes: calcining the product at 350℃~400℃ for 3h~7h in an inert atmosphere, followed by calcination at 500℃~600℃ for 3h~7h in an oxygen-containing gas atmosphere; and / or, The ammonium exchange is performed using an ammonium salt solution, wherein the ammonium salt includes ammonium nitrate, and the ammonium exchange temperature is 70°C to 90°C; and / or, The temperature of the secondary roasting is 500℃~600℃, and the time of the secondary roasting is 2h~6h.

4. The method for preparing alkylbenzene according to any one of claims 1-3, characterized in that, In the low-layer molecular sieve with MWW topology, the molar ratio of silicon to aluminum, based on SiO2 and Al2O3, is (19~75):

1.

5. The method for preparing alkylbenzene according to claim 1, characterized in that, The solid acid catalyst is prepared by the following steps: mixing the low-layer molecular sieve with MWW topology with a binder, adding inorganic acid and water, molding and drying in sequence, and then calcining at 500℃~600℃ for 4h~8h to obtain the solid acid catalyst.

6. The method for preparing alkylbenzene according to claim 1, characterized in that, In the solid acid catalyst, the mass percentage of the low-layer molecular sieve with the MWW topology is 10%~95%, with the remainder being a binder; and / or, The binder includes at least one of aluminum oxide, boehmite, boehmite, and aluminum hydroxide.

7. The method for preparing alkylbenzene according to claim 1, characterized in that, The long-chain olefins include linear olefins with 6 to 22 carbon atoms.

8. The method for preparing alkylbenzene according to claim 1, characterized in that, The molar ratio of benzene to the long-chain olefin is (5~50):

1.

9. The method for preparing alkylbenzene according to claim 1, characterized in that, The alkylation reaction conditions are as follows: temperature 100℃~200℃, pressure 1 MPa~7 MPa, and mass hourly space velocity (HHSV) of the mixture of benzene and the long-chain olefin 0.5 h⁻¹. -1 ~12 h -1 .

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