A process for the production of long chain alkylaromatics

Abstract

A production method of long-chain alkyl aromatic hydrocarbons, characterized in that it comprises an alkylation reaction process of long-chain olefins and aromatic hydrocarbons and a regeneration process of a solid acid catalyst, the solid acid catalyst being a Y-type zeolite loaded with a metal component having hydrogenolysis performance, the unit cell of the Y-type zeolite being 2.448-2.457 nm, the ratio of mesopore volume to total pore volume in the Y-type zeolite being 0.15-0.29, and the metal component having hydrogenolysis performance accounting for 0.15-5 wt% of the solid acid catalyst; the regeneration process of the solid acid catalyst being to heat the solid acid catalyst in a hydrogen atmosphere at a hydrogen temperature rising rate of 1-15 ℃ / min to 300-460 ℃ and treat it at the temperature and under the conditions of 1.5-3 MPa and a hydrogen flow rate of 150-500 mL / min / g for at least 5 h.

Description

Technical Field

[0001] This invention relates to a method for producing long-chain alkyl aromatics, and more specifically to a method for producing long-chain alkyl aromatics using a solid acid as a catalyst. Background Technology

[0002] Linear alkylbenzenes, obtained by alkylation of benzene and long-chain olefins, are important chemical intermediates in the synthesis of detergents. These intermediates can be further processed through sulfonation and neutralization to yield high-performance anionic surfactants—alkylbenzene sulfonates. The alkylation reaction of benzene and long-chain olefins laid the foundation for the synthetic detergent industry.

[0003] Currently, 83% of the world's linear alkylbenzene production uses the HF process, 9% uses the AlCl3 process, and 8% uses the Detal process.

[0004] Both the HF and AlCl3 processes suffer from drawbacks such as high environmental pollution, severe equipment corrosion, difficulty in product separation, and high investment costs. The Detal process, a solid acid process jointly developed by UOP (USA) and CEPSA (Spain), was industrialized in the mid-1990s. The Detal process uses fluorine-containing amorphous silica-alumina catalysts. However, its widespread adoption and development are limited by problems such as fluorine loss, discontinuous alkylation reactions and catalyst regeneration, high operating costs, and frequent regeneration. Therefore, green and environmentally friendly solid acid alkylation technology is the future trend.

[0005] In studies on the synthesis of straight-chain alkylbenzenes from benzene and long-chain olefins using solid acid catalysis, molecular sieves and heteropolyacid-type solid acid catalysts are frequently employed. However, their problems of easy deactivation and short single-cycle lifetime have not yet been effectively solved.

[0006] Current research largely focuses on catalytic materials or process optimization to improve single-cycle uptime, but this approach suffers from several problems, including poor catalytic material performance, frequent process operations, and high costs. For example, CN1043524C discloses a method for benzene alkylation using fluorinated silica-alumina and straight-chain monoolefins. Under alkylation conditions, benzene and C6 to C6... 20 A method for alkylating benzene involves contacting a linear monoolefin with a catalyst comprising silica and alumina in a weight ratio of 1:1 to 9:1 and a fluoride content of 1-6 wt% to induce benzene alkylation. This method achieves 98% olefin conversion, 85% or better selectivity for the resulting monoalkylbenzene, and at least 90% linearity with respect to the resulting monoalkylbenzene. However, the olefin conversion rate remains relatively low, and the method suffers from environmental pollution problems due to fluoride ion loss.

[0007] CN101535221B discloses a method for preparing alkylbenzenes on a solid acid catalyst with a low benzene to olefin ratio and low heavy matter formation. This method uses small crystals, acidic FAU molecular sieves as the catalyst under alkylation conditions.

[0008] 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 recycled back to the reactor as circulating fluid, and another portion is sent to the distillation separation system to separate excess feed and product as effluent.

[0009] 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 while the olefin 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 minutes. Summary of the Invention

[0010] The inventors discovered that solid acid catalysts prepared by supporting metals with hydrogenolysis activity on solid acids with specific physicochemical characteristics exhibit highly efficient catalytic activity in the alkylation reaction of benzene and long-chain olefins. When the catalyst is deactivated, it can be regenerated by contacting hydrogen under certain conditions to restore its activity. This ensures that the catalyst maintains good selectivity and longevity even after multiple regenerations, thereby enabling long-term stable operation of the alkylation unit. Based on this, the present invention was developed.

[0011] Therefore, the purpose of this invention is to provide a method for producing long-chain alkyl aromatics that differs from the prior art. This method can both increase the single-cycle operation time of the alkylation reaction and ensure the long-term stable operation of the alkylation unit with complete regeneration of the solid acid catalyst.

[0012] To achieve the above objectives, the present invention provides a method for producing long-chain alkyl aromatics, characterized by comprising an alkylation reaction process of long-chain olefins and aromatics and a regeneration process of a solid acid catalyst. In the alkylation reaction process of the long-chain olefins and aromatics, the alkylation reaction conditions are a temperature of 90–180°C, a pressure of 2.0–4.5 MPa, and a feed mass hourly space velocity (MHSV) of 1–30. The solid acid catalyst is a Y-type zeolite supported on a metal component with hydrogenolysis properties, wherein the Y-type zeolite has a cell size of 2.448–2. The catalyst has a pore size of 0.457 nm and a mesopore volume to total pore volume ratio of 0.15 to 0.29. The metal component with hydrogenolysis performance accounts for 0.2 to 2 wt% of the solid acid catalyst, preferably 0.4 to 1 wt%. The catalyst regeneration process involves heating the solid acid catalyst to 300-460°C in a hydrogen atmosphere at a hydrogen heating rate of 1-15°C / min and treating it at this temperature and under the conditions of 1.5-3.0 MPa and a hydrogen flow rate of 150-500 mL / min / g for at least 5 hours.

[0013] In this invention, the aromatic hydrocarbon is one or more monocyclic or polycyclic aromatic hydrocarbons, such as benzene, naphthalene, toluene, xylene, diethylbenzene, trimethylbenzene, tetramethylbenzene, and their isomers; preferably, the aromatic hydrocarbon is a monocyclic or bicyclic aromatic hydrocarbon. The total carbon number of the aromatic hydrocarbon is 6 to 18; preferably, the total carbon number of the aromatic hydrocarbon is 6 to 11; preferably, the aromatic hydrocarbon has 0 to 8 side chains, and more preferably 0 to 4 side chains. The most preferred aromatic hydrocarbon in this invention is benzene.

[0014] In this invention, the long-chain olefin includes C 10 ~C 14 One or more of the long-chain olefins. Examples of the long-chain olefins include: decene, undecene, dodecene, tridecene, tetradecene, and their isomers.

[0015] In this invention, the solid acid catalyst comprises the Y-type zeolite and an inorganic oxide matrix, wherein, based on the solid acid catalyst, the content of the Y-type zeolite is 40–95 wt%.

[0016] The inventors discovered 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, properly controlling the catalyst cell size can ensure the integrity of the catalyst crystal structure and guarantee sufficient Brønsted acid active centers 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 by the inventors 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] Y-type zeolite loaded with an appropriate amount of a metal with hydrogenolytic properties exhibits strong synergistic catalytic activity with Brønsted acid sites, resulting in better alkylation activity and selectivity under the reaction conditions of this invention. The metal with hydrogenolytic properties is selected from one or more Group VIB, VIIB, and VIII metals. 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 sites, improving catalyst lifetime. The metal with hydrogenolytic properties accounts for 0.15–5 wt% of the solid acid catalyst, preferably 0.2–2 wt%, and more preferably 0.4–1 wt%. The solid acid catalyst is obtained by impregnating Y-type zeolite with an impregnation solution containing a precursor of a metal 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.

[0019] The inorganic oxide matrix is ​​selected from one or more of silicon oxide, aluminum oxide, zirconium oxide, and titanium oxide.

[0020] In this invention, the regeneration process of the solid acid catalyst is carried out when the conversion rate of long-chain olefins is <99% during the alkylation reaction of long-chain olefins and aromatics.

[0021] The catalyst regeneration process involves heating the solid acid catalyst in a hydrogen atmosphere to 300-460°C at a hydrogen heating rate of 1-15°C / min, and treating it at this temperature and under conditions of 1.5-3.0 MPa and a hydrogen flow rate of 150-500 mL / min / g for at least 5 hours. Preferably, the regeneration process involves heating the catalyst in a hydrogen atmosphere to 340-420°C at a hydrogen heating rate of 1-10°C / min, and treating it at this temperature and under conditions of 2.0-2.8 MPa and a hydrogen flow rate of 150-400 mL / min / g for at least 5 hours. In one embodiment of the invention, the deactivated solid acid catalyst is heated in a hydrogen atmosphere to 340-360°C at a hydrogen heating rate of 2-8°C / min, and treated at this temperature and under conditions of 2.0-2.6 MPa and a hydrogen flow rate of 200-400 mL / min / g for 6 hours.

[0022] The method for producing long-chain alkyl aromatics provided by this invention optimizes the solid acid catalyst for the long-chain alkyl aromatic reaction system by improving the cell size, mesopore ratio, and the presence of metals with hydrogenolysis properties. This slows down the coking rate of the catalyst and improves the catalyst's single-cycle life. In addition, hydrogen regeneration under specific conditions can completely restore the catalyst activity, enabling long-term stable operation of the equipment.

[0023] The method for producing long-chain alkyl aromatics provided by this invention can be implemented in various reaction apparatuses, such as fluidized beds, fixed beds, and slurry beds. In this invention, the method is implemented using a fixed bed, but its application is not limited to this. The performance of the alkylation reaction is evaluated using two indicators: cycle life and product distribution. Cycle life is based on an olefin conversion rate >99%, and product distribution is based on straight-chain alkylbenzenes (LAB) and 2-LAB. The products are analyzed by gas chromatography. Detailed Implementation

[0024] 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.

[0025] 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.

[0026] Example 1

[0027] The solid acid catalyst was prepared by uniformly mixing Y-type zeolite (purchased from Sinopec Catalyst Branch) and alumina at a weight ratio of 4:1, and then loading 0.4 wt% Pt using an impregnation method. The solid acid catalyst is designated A1. The Y-type zeolite has a cell constant of 2.453 nm and a mesopore volume to total pore volume ratio of 0.22. The specific physicochemical properties are shown in Table 1.

[0028] The alkylation reaction of benzene and n-dodecene was carried out in a fixed-bed high-pressure microreactor experimental setup. 5 g of solid acid catalyst A1 was packed into a fixed-bed reactor 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 feed mass hourly space velocity (WHSV) was 7 h⁻¹. -1 (The molar ratio of benzene is 40).

[0029] The catalyst single-cycle lifetime is determined by the olefin breakthrough time in the alkylation product. Catalyst lifetime refers to the time (h) when the n-dodecene conversion rate of the linear alkylbenzene product is less than 99% after chromatography.

[0030] The alkylation regeneration conditions are shown in Table 2, and the multi-cycle reaction-regeneration 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 Technologies GC-7890B).

[0031] Comparative Example 1

[0032] This comparative example illustrates the alkylation reaction of benzene and n-dodecene using a Y-type solid acid catalyst without Pt support.

[0033] This solid acid was prepared by uniformly mixing Y-type zeolite (purchased from Sinopec Catalyst Branch) and alumina at a weight ratio of 4:1, and is labeled as B1.

[0034] The physicochemical properties of the catalyst are shown in Table 1, the alkylation regeneration conditions are shown in Table 2, and the results of the multi-cycle reaction-regeneration are shown in Table 3.

[0035] Comparative Example 2

[0036] This comparative example is used to illustrate the alkylation method using a solid acid catalyst with an excessively high metal content.

[0037] This solid acid was prepared by uniformly mixing Y-type zeolite (purchased from Sinopec Catalyst Branch) and alumina at a weight ratio of 4:1, and is labeled as B2.

[0038] The physicochemical properties of the catalyst are shown in Table 1, the alkylation regeneration conditions are shown in Table 2, and the results of the multi-cycle reaction-regeneration are shown in Table 3.

[0039] Comparative Example 3

[0040] This comparative example is used to illustrate the alkylation method using a solid acid catalyst with an excessively low supported metal content.

[0041] This solid acid was prepared by uniformly mixing Y-type zeolite (purchased from Sinopec Catalyst Branch) and alumina at a weight ratio of 4:1, and is labeled as B3.

[0042] The physicochemical properties of the catalyst are shown in Table 1, the alkylation regeneration conditions are shown in Table 2, and the results of the multi-cycle reaction-regeneration are shown in Table 3.

[0043] Comparative Example 4

[0044] This comparative example is used to illustrate alkylation methods using solid acid catalysts with different cell and mesopore ratios.

[0045] This solid acid was prepared by uniformly mixing Y-type zeolite (purchased from Sinopec Catalyst Branch) and alumina at a weight ratio of 4:1, and is labeled as B4.

[0046] The physicochemical properties of the catalyst are shown in Table 1, the alkylation regeneration conditions are shown in Table 2, and the results of the multi-cycle reaction-regeneration are shown in Table 3.

[0047] Comparative Example 5

[0048] This comparative example is used to illustrate the alkylation method using the solid acid catalyst of the present invention, but under conditions of lower regeneration temperature.

[0049] The solid acid is the same as in Example 1.

[0050] The physicochemical properties of the catalyst are shown in Table 1, the alkylation regeneration conditions are shown in Table 2, and the results of the multi-cycle reaction-regeneration are shown in Table 3.

[0051] Comparative Example 6

[0052] This comparative example illustrates the alkylation method using the solid acid catalyst of the present invention, but under conditions of lower regeneration pressure.

[0053] The solid acid is the same as in Example 1.

[0054] The physicochemical properties of the catalyst are shown in Table 1, the alkylation regeneration conditions are shown in Table 2, and the results of the multi-cycle reaction-regeneration are shown in Table 3.

[0055] Comparative Example 7

[0056] This comparative example is used to illustrate the alkylation method using the solid acid catalyst of the present invention, but under conditions of low regenerated hydrogen flow rate.

[0057] The solid acid is the same as in Example 1.

[0058] The physicochemical properties of the catalyst are shown in Table 1, the alkylation regeneration conditions are shown in Table 2, and the results of the multi-cycle reaction-regeneration are shown in Table 3.

[0059] Comparative Example 8

[0060] This comparative example is used to illustrate the alkylation method using the solid acid catalyst of the present invention, but is carried out under conditions where the regeneration heating rate is too fast.

[0061] The solid acid is the same as in Example 1.

[0062] The physicochemical properties of the catalyst are shown in Table 1, the alkylation regeneration conditions are shown in Table 2, and the results of the multi-cycle reaction-regeneration are shown in Table 3.

[0063] Comparative Example 9

[0064] This comparative example is used to illustrate the alkylation method using the solid acid catalyst of the present invention, but under conditions of a shorter regeneration isothermal time.

[0065] The solid acid is the same as in Example 1.

[0066] The physicochemical properties of the catalyst are shown in Table 1, the alkylation regeneration conditions are shown in Table 2, and the results of the multi-cycle reaction-regeneration are shown in Table 3.

[0067] Table 1

[0068]

[0069] Table 2

[0070]

[0071] Table 3

[0072]

[0073] As can be seen from the results in Table 3, the production methods of long-chain alkyl aromatics using catalysts without noble metal loading or with unsuitable metal content, such as B1, B2, B3, and B4, exhibit significantly poor initial alkylation lifetime, lifetime after six regenerations, LAB selectivity, and 2-LAB selectivity. In the regeneration step, production methods of long-chain alkyl aromatics where the regeneration temperature, pressure, hydrogen flow rate, heating rate, and isothermal time are not within the requirements of this invention, even when using the solid acid catalyst of this invention, also show poor initial alkylation lifetime, lifetime after six regenerations, LAB selectivity, and 2-LAB selectivity. The production method of long-chain alkyl aromatics provided by this invention, due to the use of a solid acid catalyst loaded with an appropriate amount of metal Pt and regeneration under hydrogen-exposed conditions, demonstrates a strong synergistic catalytic effect between Pt and the Brønsted acid sites. Under the reaction conditions provided by this invention, it exhibits better alkylation activity and selectivity. Simultaneously, hydrogen-exposed regeneration provides good regeneration activity, ensuring long-term stable operation of the catalyst. For example, catalyst Al with a Pt content of 0.4% not only has an initial lifetime of 42 hours, but also a LAB selectivity of up to 91.2% and a 2-LAB ratio of up to 26.2% after six regenerations.

[0074] Example 2

[0075] This embodiment illustrates the solid acid alkylation method of the present invention.

[0076] The solid acid catalyst was prepared by uniformly mixing Y-type zeolite (purchased from Sinopec Catalyst Branch) and alumina at a weight ratio of 4:1, and then loading 0.2 wt% Pt onto the mixture using an impregnation method. The solid acid catalyst was designated A2. The Y-type zeolite had a cell constant of 2.448 nm and a mesopore volume to total pore volume ratio of 0.15.

[0077] The physicochemical properties of the catalyst are shown in Table 4, the alkylation regeneration conditions are shown in Table 5, and the results of the multi-cycle reaction-regeneration are shown in Table 6.

[0078] Example 3

[0079] This embodiment illustrates the solid acid alkylation method of the present invention.

[0080] The solid acid catalyst was prepared by uniformly mixing Y-type zeolite (purchased from Sinopec Catalyst Branch) and alumina at a weight ratio of 4:1, and then loading 2 wt% Pt using an impregnation method. The solid acid catalyst was designated A3. The Y-type zeolite had a cell constant of 2.457 nm and a mesopore volume to total pore volume ratio of 0.29. The resulting solid acid catalyst was designated A3.

[0081] The physicochemical properties of the catalyst are shown in Table 4, the alkylation regeneration conditions are shown in Table 5, and the results of the multi-cycle reaction-regeneration are shown in Table 6.

[0082] Table 4

[0083]

[0084] Table 5

[0085]

[0086] Table 6

[0087]

Claims

1. A method for producing long-chain alkyl aromatics, characterized in that, This includes an alkylation reaction process involving long-chain olefins and aromatics, and a regeneration process for a solid acid catalyst; the long-chain alkyl aromatics are obtained by alkylation of long-chain olefins and aromatics, wherein the long-chain olefins are C14-244-32 ... 10 ~C 14 The alkylation reaction involves one or more long-chain olefins, wherein the aromatic hydrocarbon is one or more monocyclic or polycyclic aromatic hydrocarbons, and the total number of carbon atoms in the aromatic hydrocarbon is 6–18; during the alkylation reaction of the long-chain olefin and the aromatic hydrocarbon, the alkylation reaction conditions are a temperature of 90–180 °C, a pressure of 2.0–4.5 MPa, and a feed mass hourly space velocity of 1–30 h⁻¹. -1 The solid acid catalyst is a Y-type zeolite supported on a metal component with hydrogenolysis properties; the metal with hydrogenolysis properties is Pt; the Y-type zeolite has a cell size of 2.448–2.457 nm and a mesopore volume to total pore volume ratio of 0.15–0.29, and the metal component with hydrogenolysis properties accounts for 0.15–2 wt% of the solid acid catalyst; the regeneration process of the solid acid catalyst involves heating the solid acid catalyst in a hydrogen atmosphere to 300–460 °C at a heating rate of 1–15 °C / min and treating it at this temperature and under conditions of 1.5–3 MPa and a hydrogen flow rate of 150–500 mL / min / g for at least 5 h.

2. The production method according to claim 1, characterized in that, The solid acid catalyst also includes an inorganic oxide matrix.

3. The production method according to claim 2, characterized in that, The inorganic oxide is selected from one or more of silicon oxide, aluminum oxide, zirconium oxide, and titanium oxide.

4. The production method according to claim 1, characterized in that, Based on solid acid catalysts, the content of Y-type zeolite is 40-95 wt%.

5. The production method according to claim 1, characterized in that, The Y-type zeolite has a cell size of 2.452–2.455 nm.

6. The production method according to claim 1, characterized in that, The Y-type zeolite has a mesopore volume to total pore volume ratio of 0.18 to 0.

26.

7. The production method according to claim 1, characterized in that, The hydrogenolysis metal accounts for 0.2 to 2 wt% of the solid acid catalyst.

8. The production method according to claim 7, characterized in that, The hydrogenolysis metal accounts for 0.4 to 1 wt% of the solid acid catalyst.

9. The production method according to claim 1, characterized in that, The regeneration process of the solid acid catalyst is carried out when the conversion rate of long-chain olefins is <99% during the alkylation reaction of long-chain olefins and aromatics.

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