Process for the alkylation of aromatic and long-chain olefinic hydrocarbons

Abstract

A process for the alkylation of an aromatic hydrocarbon and a long-chain olefin, which comprises contacting the starting aromatic hydrocarbon and the starting long-chain olefin under alkylation reaction conditions, characterized in that the process uses as catalyst a solid acid loaded with a metal having hydrogenolysis properties, and comprises a step I of periodically interrupting the feeding of the starting aromatic hydrocarbon and the starting long-chain olefin and contacting the catalyst with an aromatic substance, during a period in which the conversion of the starting long-chain olefin is ≥ 99%, and a step II of contacting the catalyst with hydrogen, when the conversion of the starting long-chain olefin is < 99%.

Description

Technical Field

[0001] This invention relates to a solid acid alkylation reaction method, and more specifically, to an alkylation reaction method for preparing straight-chain alkyl aromatics using a solid acid as a catalyst and aromatics and long-chain olefins as raw materials. Background Technology

[0002] Linear alkylbenzenes, obtained by alkylation of benzene and long-chain olefins, are an important chemical intermediate in the synthesis of various detergents. This intermediate can be further processed through sulfonation and neutralization to yield alkylbenzene sulfonates, a high-performance anionic surfactant. This reaction, which began in the 1940s, laid the foundation for the synthetic detergent industry.

[0003] Currently, 83% of global linear alkylbenzene production uses the HF process, 9% uses the AlCl3 process, and 8% uses the DEL process. Both the HF and AlCl3 processes have various drawbacks, including high environmental pollution, severe equipment corrosion, difficulty in product separation, and high investment costs.

[0004] The Detal process is a solid acid process jointly developed by UOP (United States Petroleum Corporation) and CEPSA (Spain Petroleum Company), and was industrialized in the mid-1990s. Because the Detal process uses a fluorine-containing amorphous silica-alumina catalyst, it suffers from problems such as fluorine loss, discontinuous alkylation reactions and catalyst regeneration, high operating costs, and frequent regeneration, which to some extent limits its widespread adoption and development.

[0005] Developing green and environmentally friendly solid acid alkylation technology is a future trend. Research institutes such as the Petrochemical Research Institute, East China University of Science and Technology, Nanjing Alkylbenzene Plant, and the Dalian Institute of Chemical Physics, Chinese Academy of Sciences, have all conducted research on the synthesis of straight-chain alkylbenzenes from benzene and long-chain olefins via solid acid catalysis, primarily employing molecular sieves and heteropolyacid-type solid acid catalysts. However, the problems of easy deactivation and short single-cycle lifespan of solid acid catalysts have not been effectively solved. Therefore, developing green solid acid catalyst technology that enables long-term stable operation and easy regeneration has significant economic and social benefits.

[0006] To improve the single-cycle lifetime and extend the stable operating time of solid acid catalysts in this reaction, research has largely focused on the synthesis of catalytic materials or process optimization from a process perspective; however, for the regeneration of solid acid catalysts, solvent elution is commonly used. These methods generally suffer from poor reaction performance of the catalytic materials, frequent regeneration process operations, and high costs.

[0007] CN1043524C discloses a method for benzene alkylation using fluorinated silica-alumina and straight-chain monoolefins. Under alkylation conditions, benzene and straight-chain monoolefins are contacted with a fluorinated silica-alumina catalyst comprising silica and alumina in a weight ratio of 1:1 to 9:1 and a fluoride content of 1 to 6 wt%, using C6 to C4 olefins. 20 A linear monoolefin is used to alkylate benzene, achieving 98% olefin conversion, 85% or better selectivity for the monoalkylbenzene, and at least 90% linearity with respect to the monoalkylbenzene produced. However, this method suffers from low olefin conversion and environmental pollution problems due to fluoride ion loss.

[0008] CN101535221A discloses a method for preparing alkylbenzenes on a solid acid catalyst with a low benzene to olefin ratio and low heavy matter formation, wherein small crystals and acidic FAU molecular sieves are used as catalysts.

[0009] CN111514924A discloses a catalytic synthesis method for long-chain alkyl aromatics, the method comprising: first, feeding the raw material aromatics into a fixed-bed alkylation reactor and filling the reactor; then, feeding the raw material aromatics and raw material C6-C... 24 A mixture of long-chain olefins and additive long-chain alkyl aromatic solvents or long-chain alkane solvents is fed into a fixed-bed reactor and contacted with an SBA-15 type mesoporous molecular sieve alkylation solid acid catalyst to carry out the alkylation reaction of aromatics and long-chain olefins, generating long-chain alkyl aromatics as the product. A portion of the effluent from the alkylation reactor is used as the reactor's circulating fluid, while the other portion is sent to a distillation separation system to separate the excess feed and product effluent.

[0010] US5648579A discloses a method for the alkylation reaction of benzene and 1-dodecene using a pulsed feed method. In this method, benzene is continuously fed into the feedstock, while the 1-dodecene feed is stopped at intervals to achieve pulsed feed. The molar ratio of benzene to olefin is between 8 and 20, the number of carbon atoms in the straight-chain olefin is between 10 and 14, and the pulse feed interval is between 10 and 60 mins. Summary of the Invention

[0011] The inventors discovered that after an alkylation reaction of aromatics and long-chain olefins for a certain period of time, treating a solid acid catalyst supported on a metal with hydrogenolysis properties under a hydrogen atmosphere, followed by flushing the solid acid catalyst with aromatic substances at appropriate times and conditions, can completely restore the alkylation activity of the solid acid catalyst. This significantly improves the stable operating time of the solid acid catalyst in the reaction-regeneration mode and maintains high selectivity for straight-chain aromatic products. Based on this, the present invention was developed.

[0012] Therefore, the purpose of this invention is to provide an alkylation reaction method for aromatics and long-chain olefins that differs from the prior art. This method can not only extend the single-cycle life of the catalyst and the product selectivity, but also ensure the long-term stable operation of the reaction unit.

[0013] To achieve the above objectives, the present invention provides an alkylation reaction method for aromatic hydrocarbons and long-chain olefins, wherein the raw material aromatic hydrocarbons and raw material long-chain olefins are contacted and reacted under alkylation reaction conditions. The method is characterized by using a solid acid supported on a metal with hydrogenolysis properties as a catalyst, and includes step I, which involves periodically stopping the feed of the raw material aromatic hydrocarbons and raw material long-chain olefins and contacting them with an aromatic substance while the conversion rate of the raw material long-chain olefins is ≥99%; and step II, which involves contacting the solid acid with hydrogen when the conversion rate of the raw material long-chain olefins is <99%.

[0014] In this invention, the alkylation reaction conditions are as follows: temperature 70–280°C, pressure 1.5–5 MPa, and mass hourly space velocity (MSV) of the feedstock, including aromatic hydrocarbons and long-chain olefins, 1–20. The molar ratio of aromatic hydrocarbons to long-chain olefins is 5–100:1.

[0015] In this invention, the solid acid contains 20–95 wt% molecular sieve and 5–80 wt% inorganic oxide. The molecular sieve is one or more of the FAU, MWW, MOR, and BEA type topologies, preferably an FAU type molecular sieve, and more preferably a Y molecular sieve.

[0016] Studies have found that the deactivation of the alkylation reaction of aromatics and long-chain olefins is caused by the blockage of catalyst pores by the heavy alkyl aromatics generated during the reaction. This reaction can be catalyzed not only by Brønsted acid but also by Lewis acid. Therefore, proper control of the catalyst cell size can ensure the integrity of the catalyst crystal structure and guarantee sufficient Brønsted acid active sites for the reaction. Therefore, the Y-type zeolite described in this invention has a cell size of 2.448–2.457 nm, preferably 2.452–2.455 nm.

[0017] Further research in this invention revealed that, since heavy alkyl aromatics are key to catalyst deactivation, a specific ratio of mesopores can promote the timely diffusion of macromolecules such as heavy alkyl aromatics from the pores, thus delaying catalyst coking. The ratio of mesopore volume to total pore volume is 0.15–0.29, preferably 0.18–0.26. Both the mesopore volume and total pore volume described in this invention can be determined by static low-temperature nitrogen adsorption capacity method (BET). BET determination is well-known to those skilled in the art; for example, it can be performed using an ASAP2420 adsorption instrument from Mack Company, USA. The determination process is as follows: the sample is first dried in an oven at 110°C for 2 hours to remove surface water. Then, a certain amount of sample is weighed and placed in a degassing unit, evacuated to a vacuum degree less than 1.33 Pa, and treated at 90°C for 1 hour, followed by heating to 330°C for 9–10 hours. The sample is then subjected to nitrogen adsorption-desorption testing under liquid nitrogen cooling conditions to obtain adsorption-desorption curves. The specific surface area and pore volume are calculated using the BET formula.

[0018] The inorganic oxide is selected from one or more of silicon oxide, aluminum oxide, zirconium oxide, and titanium oxide.

[0019] In this invention, a solid acid Y-type zeolite is loaded with an appropriate amount of a metal with hydrogenolytic properties, exhibiting a strong synergistic catalytic effect with Brønsted acid sites. Under the reaction conditions of this invention, it demonstrates better alkylation activity and selectivity. The metal with hydrogenolytic properties is selected from one or more metals of Group VIB, VIIB, and VIII. The Group VIII metal is selected from one or more of Pt, Pd, and Ru, with Pt being preferred. Pt can both synergize with Brønsted acid and serve as a source of some Lewis acid centers, thus improving catalyst lifetime. The metal with hydrogenolytic properties accounts for 0.15–5 wt% of the solid acid catalyst, preferably 0.2–2 wt%. The solid acid catalyst is obtained by impregnating Y-type zeolite with an impregnation solution containing a precursor with hydrogenolytic properties, followed by drying, calcination, and reduction. The Pt precursor can be selected from one or more of chloroplatinic acid, ammonium chloroplatinate, potassium chloroplatinate, platinum tetrachloride, or tetraammineplatinum nitrate. During the alkylation reaction, the noble metal in the solid acid catalyst remains in a metallic state.

[0020] In this invention, the raw material aromatic hydrocarbon has a total carbon number of 6-18, preferably 6-11, such as benzene, toluene, xylene, diethylbenzene, trimethylbenzene, tetramethylbenzene, and their isomers. The raw material aromatic hydrocarbon has a side chain with a side chain carbon number of 0-8, preferably 0-4, such as benzene, toluene, xylene, diethylbenzene, trimethylbenzene, tetramethylbenzene, and their isomers. The raw material long-chain olefin includes C... 10 ~C 14One or more of the long-chain olefins, such as decene, undecene, dodecene, tridecene, tetradecene and their isomers.

[0021] In this invention, step I is carried out during the period when the conversion rate of the raw material long-chain olefin is ≥99%, after the alkylation reaction of the raw material aromatic hydrocarbon and the raw material long-chain olefin is carried out at intervals of 5 to 36 hours, preferably 10 to 28 hours, and step I can be performed multiple times.

[0022] The composition of the alkylation feedstock and product was analyzed using an Agilent Technologies 7890A gas chromatograph with a DB-5MS column. The column oven temperature program was 50°C for 5 min, then increased to 300°C at a rate of 5°C / min and held for 5 min. The detector was a flame ionization detector (FID) with an H2 flow rate of 40 mL / min, an air flow rate of 400 mL / min, and an N2 make-up flow rate of 25 mL / min.

[0023] The conversion rate of the feedstock long-chain olefins is calculated using the following formula:

[0024] Long-chain olefin conversion: x=((w Oi -w Of ) / w Oi )×100%

[0025] In the formula, w Oi w represents the mass fraction of long-chain olefins in the feedstock before the reaction. Of This represents the mass fraction of the long-chain olefin after the reaction.

[0026] To carry out step I, the alkylation reaction temperature needs to be increased to the temperature required for step I. The heating rate can be 1–20 °C / min, preferably 3–15 °C / min, and more preferably 5–12 °C / min.

[0027] In step I, the aromatic hydrocarbon is one or more monocyclic or polycyclic aromatic hydrocarbons, such as benzene, toluene, xylene, diethylbenzene, trimethylbenzene, tetramethylbenzene, and their isomers. At least from the perspective of ease of operation, preferably, the feedstock aromatic hydrocarbon is the same as that described in step I, meaning that stopping the feedstock long-chain olefin can achieve this.

[0028] In step I, the aromatic substance comes into contact with a solid acid at a temperature of 130–350°C, preferably 155–280°C. The mass hourly space velocity (HHSV) of the aromatic substance is 1–100 h⁻¹. -1 Preferably 5-60h -1 The aromatic substance is contacted with the solid acid for 1 to 72 hours, preferably 10 to 36 hours, and more preferably 15 to 28 hours.

[0029] In this invention, step II involves contacting a solid acid catalyst with hydrogen when the conversion rate of the long-chain olefin feedstock is <99%. Step II can be performed multiple times. To implement step II, the alkylation reaction temperature needs to be increased to the temperature required for step II. The heating rate can be 1–20 °C / min, preferably 1–15 °C / min, and more preferably 1–12 °C / min.

[0030] In step II, the solid acid is contacted with hydrogen at a temperature of 150–500°C and a pressure of 0–5 MPa, preferably at 250–480°C and 1.5–4 MPa, and more preferably at 350–450°C. The hydrogen flow rate is 1–500 mL / min / g catalyst, preferably 20–400 mL / min / g catalyst. The time is 1–10 h, preferably 3–8 h.

[0031] The inventors discovered that in the alkylation reaction of aromatics and long-chain olefins catalyzed by solid acid, the deactivation of the solid acid is caused by the blockage of the solid acid channels by large molecular weight heavy alkyl aromatics generated during the reaction. Treating the solid acid with aromatics after the alkylation reaction has proceeded for a period of time can largely remove the carbon-depositing precursors such as large molecular weight heavy alkyl aromatics generated in the solid acid channels, thus extending the catalyst's single-cycle life. Furthermore, after the solid acid is deactivated (i.e., manifested as a decrease in long-chain olefin conversion to <99%), treating the solid acid with hydrogen can almost completely remove the carbon-deposited components from the solid acid, restoring its catalytic activity. The method provided by this invention, at different stages of long-chain olefin conversion in the alkylation reaction, employs a combination of step I (periodic treatment of the solid acid with aromatics) when the long-chain olefin conversion is ≥99%, and step II (treatment of the solid acid with hydrogen) when the long-chain olefin conversion is <99%.

[0032] The inventors further discovered that these two steps alone are far from sufficient. To achieve good LAB selectivity and a 2-LAB ratio while significantly improving the single-cycle life of solid acid and extending the stable operation time of the device, it is necessary to properly match the operating parameters of steps I and II. For example, the operating parameters in step I, which uses aromatics to treat solid acid, include the interval between two adjacent aromatic treatments, the heating rate to raise the alkylation reaction temperature to the temperature required for step I, the treatment temperature, pressure, the mass hourly space velocity of the aromatics, and the aromatics treatment time. Similarly, the operating parameters in step II, which uses hydrogen to treat solid acid, include temperature, pressure, the heating rate to raise the alkylation reaction temperature to the temperature required for step II, the hydrogen flow rate, and the isothermal treatment time. Detailed Implementation

[0033] The present invention will be described in detail below through embodiments. It should be understood that the specific embodiments described herein are only for illustration and explanation of the present invention, but do not limit the scope of the present invention.

[0034] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0035] Example 1

[0036] The raw material aromatic hydrocarbon is benzene, the raw material long-chain olefin is n-dodecene, and the solid acid catalyst is Y molecular sieve (purchased from Sinopec Catalyst Branch) and alumina mixed at a weight ratio of 4:1. The mixture is then prepared by impregnation with 0.4wt% Pt. The resulting solid acid catalyst is designated A1. The Y molecular sieve has a cell constant of 2.448 nm and a mesopore volume to total pore volume ratio of 0.05.

[0037] The alkylation reaction was carried out in a fixed-bed high-pressure microreactor. 5 g of catalyst was packed into a fixed-bed high-pressure microreactor with an inner diameter of 10 mm and a length of 1 m. The reaction temperature was 120 °C, the reaction pressure was 3 MPa, and the feedstock (benzene and n-dodecene) had a mass hourly space velocity (H₂S₀) of 7 h⁻¹. -1 The molar ratio of benzene is 40.

[0038] The single-cycle lifetime of the solid acid was determined by the breakthrough time of n-dodecene in the product of the alkylation reaction. The single-cycle lifetime refers to the total time (h) during which the catalyst treats the feedstock within the time (h) when the conversion of n-dodecene is ≥99%. The conversion of n-dodecene was obtained by gas chromatography analysis of the product and calculated by the following formula.

[0039] n-Dodecene conversion rate: x = ((w0 - w) p ) / w0)×100%

[0040] w0 represents the mass fraction of n-dodecene in the feedstock before the reaction; w p This represents the mass fraction of n-dodecene after the reaction.

[0041] When the conversion rate of n-dodecene is ≥99%, the scheme of step I is implemented on the solid acid catalyst, and the aromatic substance used is benzene, until the conversion rate of n-dodecene is <99%. The specific conditions of step I are shown in Table 1.

[0042] When the conversion rate of n-dodecene is <99%, the scheme of step II is implemented for the solid acid catalyst, and the specific conditions are shown in Table 2.

[0043] The alkylation results are shown in Table 3. In Table 3, LAB and 2-LAB represent the selectivity of linear alkylbenzenes and 2-LAB in the product. The components in the linear alkylbenzene product were analyzed using an online chromatographic analyzer (Agilent GC-7890B).

[0044] Comparative Example 1

[0045] This comparative example is the same as Example 1, except that steps I and II of Example 1 are not used.

[0046] The results of the alkylation reaction are shown in Table 3.

[0047] Comparative Example 2

[0048] This comparative example is the same as Example I, except that step II of Example 1 was not used.

[0049] The specific conditions for step I are shown in Table 1, and the results of the alkylation reaction are shown in Table 3.

[0050] Comparative Example 3

[0051] This comparative example is the same as Example 1, except that step I of Example 1 was not used.

[0052] The specific conditions for step II are shown in Table 2, and the results of the alkylation reaction are shown in Table 3.

[0053] Example 2

[0054] In this embodiment, the alkylation reaction conditions and step II are the same as in Example 1, except that the operating parameters in step I are not the optimal conditions.

[0055] The specific conditions for step I are shown in Table 1, the specific conditions for step II are shown in Table 2, and the results of the alkylation reaction are shown in Table 3.

[0056] Example 3

[0057] In this embodiment, the alkylation reaction conditions and step I are the same as in Example 1, except that the operating parameters in step II are not the optimal conditions.

[0058] The specific conditions for step I are shown in Table 1, the specific conditions for step II are shown in Table 2, and the results of the alkylation reaction are shown in Table 3.

[0059] Table 1

[0060]

[0061] Table 2

[0062]

[0063] Table 3

[0064]

[0065] The results in Table 3 show that:

[0066] (1) The alkylation reaction of benzene and n-dodecene using the method of Example 1 of the present invention is the most effective and significantly better than Comparative Example 1, which does not use either step I or step II.

[0067] (2) The alkylation reaction of Comparative Example 2, which uses only step I, and Comparative Example 3, which uses only step II, is not as effective as that of Example 1.

[0068] (3) Even if both steps I and II are used, if one of the operating parameters selected in step I or step II is not within the preferred range, the alkylation reaction effect is much worse than that in Example 2 and Example 3.

[0069] Example 4

[0070] Same as Example 1, except that the Y molecular sieve used had a cell constant of 2.453 nm and a mesopore / total pore value of 0.22. The alkylation reaction results are shown in Table 4.

[0071] Example 5

[0072] Same as Example 1, except that the Y molecular sieve used had a cell constant of 2.455 nm and a mesopore / total pore value of 0.18. The alkylation reaction results are shown in Table 4.

[0073] Example 6

[0074] Same as Example 1, except that the Y molecular sieve used had a cell constant of 2.452 nm and a mesopore / total pore value of 0.29. The alkylation reaction results are shown in Table 4.

[0075] Table 4

[0076]

Claims

1. A method for alkylation reaction of aromatic hydrocarbons and long-chain olefins, characterized in that the aromatic hydrocarbon and long-chain olefin are reacted in contact under alkylation reaction conditions, wherein... The method uses a solid acid supported on a metal with hydrogenolysis properties as a catalyst, and includes step I, which involves stopping the feed of aromatic hydrocarbons and long-chain olefins and contacting the catalyst with an aromatic hydrocarbon every 5 to 36 hours during the period when the conversion rate of the feed long-chain olefins is ≥99%; and step II, which involves contacting the catalyst with hydrogen when the conversion rate of the feed long-chain olefins is <99%. The aromatic hydrocarbons used as raw materials have a total carbon number of 6 to 18; the long-chain olefins used as raw materials have a carbon number of C10. 10 ~C 14 One or more of the long-chain olefins; The solid acid contains 20-95 wt% Y molecular sieve and 5-80 wt% inorganic oxide; the Y molecular sieve has a cell constant of 2.448-2.457 nm and a mesopore volume to total pore volume ratio of 0.15-0.

29. Step I is carried out at 5-36 h intervals during the period when the conversion rate of the feedstock long-chain olefin is ≥99%. The contact temperature between the feedstock aromatics and the feedstock long-chain olefin and the catalyst in Step I is 130-350 °C, and the space velocity of the aromatics is 1-100 h⁻¹. -1 The contact time between the aromatics and the catalyst is 1 to 72 hours; the heating rate from the alkylation reaction temperature to the temperature of step I is 1 to 20 °C / min. In step II, the temperature is 150–500°C, the pressure is 0–5 MPa, the hydrogen flow rate is 1–500 mL / min / g catalyst, the catalyst is contacted with hydrogen, and the isothermal time is 1–10 h; the heating rate from the alkylation reaction temperature to the temperature of step II is 1–20°C / min.

2. The method according to claim 1, characterized in that, The alkylation reaction conditions are as follows: temperature 70–280°C, pressure 1.5–5 MPa, and feed mass hourly space velocity (WHSV) 1–20 h⁻¹. -1 The raw materials include aromatic hydrocarbons and long-chain olefins.

3. The method according to claim 1, characterized in that, The Y molecular sieve has a cell constant of 2.452–2.455 nm and a mesopore volume to total pore volume ratio of 0.18–0.

26.

4. The method according to claim 1, characterized in that, The inorganic oxide is selected from one or more of silicon oxide, aluminum oxide, zirconium oxide, and titanium oxide.

5. The method according to claim 1, characterized in that, The metal with hydrogenolysis properties is selected from one or more metals of groups VIB, VIIB, and VIII.

6. The method according to claim 1, characterized in that, The metal with hydrogenolysis properties is selected from one or more metals of Group VIII.

7. The method according to claim 1, characterized in that, The metal with hydrogenolysis properties is selected from one or more of Pt, Pd, and Ru.

8. The method according to claim 1, characterized in that, The raw material aromatic hydrocarbons have a total carbon number of 6 to 12.

9. The method according to claim 1, characterized in that, The raw material aromatic hydrocarbon has a side chain carbon number of 0 to 8.

10. The method according to claim 9, characterized in that, The raw material aromatic hydrocarbon has a side chain carbon number of 0 to 6.

11. The method according to claim 1, characterized in that, The aromatic hydrocarbons used as raw materials are selected from one or more of benzene, toluene, xylene, diethylbenzene, trimethylbenzene, tetramethylbenzene, and their isomers.

12. The method according to claim 1, characterized in that, The raw material aromatic hydrocarbon is benzene.

13. The method according to claim 1, characterized in that, The raw material long-chain olefins are selected from decene, undecene, dodecene, tridecene, tetradecene and their isomers.

14. The method according to claim 1, characterized in that, The aromatic hydrocarbon mentioned in step I is one or more monocyclic or polycyclic aromatic hydrocarbons.

15. The method according to claim 1, characterized in that, The aromatic hydrocarbons mentioned in step I are benzene, toluene, xylene, diethylbenzene, trimethylbenzene, tetramethylbenzene and their isomers.

16. The method according to claim 1, characterized in that, The aromatic substance mentioned in step I is the same as the raw material aromatic substance.

17. The method according to claim 1, characterized in that, The contact temperature in step I, where aromatic substances come into contact with the catalyst, is 155–280 °C.

18. The method according to claim 1, wherein the heating rate from the alkylation reaction temperature to the temperature of step I is 1 to 10 °C / min.

19. The method according to claim 1, characterized in that, In step I, where the aromatic hydrocarbon comes into contact with the catalyst, the space velocity of the aromatic hydrocarbon is 2–60 h⁻¹. -1 .

20. The method according to claim 1, characterized in that, In step I, the contact time between the aromatic substance and the catalyst is 5 to 36 hours.

21. The method according to claim 1, characterized in that, In step II, the temperature is 250–480°C and the pressure is 1.5–4 MPa.

22. The method according to claim 21, characterized in that, In step II, the temperature is 350℃~450℃.

23. The method according to claim 1, characterized in that, The heating rate from the alkylation reaction temperature to the temperature of step II is 1–10 °C / min.

24. The method according to claim 1, characterized in that, In step II, the hydrogen flow rate is 20–400 mL / min / g catalyst.

25. The method according to claim 1, characterized in that, In step II, the catalyst is contacted with hydrogen and kept at a constant temperature for 3–8 hours.

26. The method according to claim 1, characterized in that, Step I is carried out after the contact reaction of the raw material aromatic hydrocarbon and the raw material long-chain olefin for 10–28 h, under the following conditions: the heating rate from the temperature of the alkylation reaction to the temperature of Step I is 1–15 °C / min; the contact temperature between the aromatic hydrocarbon and the catalyst is 155–280 °C for 10–36 h; and the space velocity of the aromatic hydrocarbon is 5–60 h⁻¹. -1 In step II, from the alkylation reaction to step II, the heating rate is 1-15℃ / min, the pressure is 1.5-4MPa, the hydrogen flow rate is 20-400mL / min / g catalyst, and the isothermal treatment time for the catalyst to contact with hydrogen is 3-8h.

27. The method according to claim 1 or 26, characterized in that, Perform steps I and II multiple times.

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