Hydrogen-type ZSM-5 / ZSM-12 / SAPO-11 composite molecular sieve, and preparation method and application thereof

Abstract

The application discloses a hydrogen type ZSM-5 / ZSM-12 / SAPO-11 composite molecular sieve and a preparation method and application thereof, and belongs to the fine chemical industry field. The preparation method comprises the following steps: uniformly mixing ZSM-5 pre-crystallization solution, ZSM-12 pre-crystallization solution and SAPO-11, co-crystallizing at 150-200 DEG C for 1-4 days, and then performing primary calcination to obtain the ZSM-5 / ZSM-12 / SAPO-11 composite molecular sieve. The composite molecular sieve disclosed by the application has the advantages of high activity, good 2,6-DMN selectivity and carbon deposition resistance, the molar ratio of 2,6-DMN to 2,7-DMN in the product is high, the separation difficulty is relatively low, and the composite molecular sieve has great industrial application prospect in the preparation of 2,6-DMN through the catalytic naphthalene / 2-methylnaphthalene methanol alkylation reaction.

Description

Technical Field

[0001] This invention belongs to the field of fine chemical technology and relates to a method for preparing silicon-aluminum / phosphorus-aluminum molecular sieves and their applications, specifically to a hydrogen-form ZSM-5 / ZSM-12 / SAPO-11 composite molecular sieve, its preparation method, and its applications. Background Technology

[0002] Polyethylene naphthalate (PEN) resin possesses excellent mechanical properties, chemical stability, optical properties, heat resistance, and gas barrier properties. It is primarily used in flexible circuit boards, novel display materials, OLED encapsulation materials, and films for extreme environments, making it a key raw material in the electronics and information industry. 2,6-DMN, as a crucial raw material for synthesizing high-performance PEN resin, suffers from a complex synthesis process, low production efficiency, and difficulties in product separation, resulting in persistently high production costs. This severely restricts the development of the high-end electronics and information industry.

[0003] Currently, there are three feasible industrial processes for the production of 2,6-DMN. The first is the toluene alkylation method, where toluene and 1-pentene undergo high-temperature alkylation, followed by catalytic cyclization, hydrogenation, dehydrogenation, and dehydroisomerization to obtain a crude product, which is then purified to obtain pure 2,6-DMN. The second is the o-xylene-butadiene alkylation method, where o-xylene and butadiene are first alkylated, followed by cyclization and dehydroisomerization to obtain 2,6-DMN. The third is the alkylation method of naphthalene / 2-methylnaphthalene (2-MN), where naphthalene / 2-MN is alkylated with methanol, followed by purification to prepare 2,6-DMN.

[0004] The alkylation of naphthalene / 2-MN can generate 2,6-DMN in one step. This method has a short process flow, uses inexpensive and readily available raw materials, and is relatively easy to separate the product, making it considered the most efficient and low-cost production method. The mechanism of the naphthalene / 2-MN methanol alkylation reaction is as follows: naphthalene is alkylated to obtain 2-MN. Methanol then attacks the active site of 2-MN to obtain a mixture containing the target product 2,6-DMN and its nine isomers. After separation and purification, 2,6-DMN is obtained. Increasing the probability of methanol attacking the 6th active site of 2-MN is key to improving the selectivity of the target product. Among the ten DMN isomers generated in the reaction, increasing the molar ratio of 2,6-DMN to 2,7-DMN will be more beneficial for the subsequent separation and purification of 2,6-DMN.

[0005] Molecular sieves possess advantages such as structural stability, high specific surface area, and easily tunable acidic pore size, making them the preferred catalysts for the synthesis of 2,6-DMN. In recent years, domestic and international scholars have conducted extensive research on mainstream molecular sieve catalysts for the alkylation reaction of naphthalene / 2-MN to prepare 2,6-DMN, including ZSM-5, β, SAPO-11, ZSM-12, and HY. Among them, the ZSM-5 catalyst exhibits good catalytic activity due to its relatively strong acidity, achieving conversion rates of 40-65%, but its relatively low conversion rate limits its application. The SAPO-11 catalyst has weaker acidity, resulting in a lower conversion rate of approximately 10-40%, but its advantage lies in its high selectivity. The unique structure of the ZSM-12 catalyst results in a significantly lower diffusion barrier for 2,6-DMN compared to 2,7-DMN, which can significantly increase the molar ratio of 2,6-DMN to 2,7-DMN in the product, facilitating subsequent separation. Therefore, synthesizing a comprehensive catalyst with high activity, high 2,6-DMN selectivity, and a high molar ratio of 2,6-DMN to 2,7-DMN in the product is key to the efficient and low-cost production of 2,6-DMN. Summary of the Invention

[0006] To address the problems in the prior art, the present invention aims to propose a hydrogen-form ZSM-5 / ZSM-12 / SAPO-11 composite molecular sieve, its preparation method, and its application. This molecular sieve avoids the defects of single molecular sieves and has great application value in the catalytic alkylation reaction of naphthalene / 2-MN to prepare 2,6-DMN.

[0007] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0008] A method for preparing a hydrogen-form ZSM-5 / ZSM-12 / SAPO-11 composite molecular sieve includes the following steps:

[0009] The ZSM-5 precrystallization solution, ZSM-12 precrystallization solution and SAPO-11 were mixed evenly and co-crystallized at 150-200℃ for 1-4 days, and then calcined once to obtain ZSM-5 / ZSM-12 / SAPO-11 composite molecular sieve.

[0010] The ZSM-5 / ZSM-12 / SAPO-11 composite molecular sieve was soaked in ammonium nitrate solution and dried to obtain ammonium-type zeolite. The ammonium-type zeolite was then calcined a second time to obtain hydrogen-type ZSM-5 / ZSM-12 / SAPO-11 composite molecular sieve.

[0011] Furthermore, the mass ratio of ZSM-5 precrystallization solution, ZSM-12 precrystallization solution to SAPO-11 is 15-40:10-35:25-75; the first calcination temperature is 400-600℃ and the time is 3-6h; the second calcination temperature is 500-700℃ and the time is 4-6h.

[0012] Furthermore, the ZSM-5 pre-crystallized solution is prepared through the following process:

[0013] Sodium and aluminum sources were dissolved in deionized water, and then template agent and silicon source were added. After stirring, a gel was formed, and the gel was pre-crystallized at 160-200℃ for 6-24 hours to obtain ZSM-5 pre-crystallized solution.

[0014] Furthermore, the sodium source is sodium hydroxide, the aluminum source is sodium aluminate, the template agent is tetrapropylammonium hydroxide, and the silicon source is water glass or tetraethyl orthosilicate.

[0015] The amounts of sodium source, aluminum source, template agent and silicon source are determined according to the molar ratio of Na2O:Al2O3:SiO2:TPAOH:H2O = 40~50:0.5~1.6:130~160:45~60:2500~3600.

[0016] Furthermore, the amounts of sodium source, aluminum source, template agent and silicon source are determined according to the molar ratio of Na2O:Al2O3:SiO2:TPAOH:H2O = 43~48:0.8~1.2:140~150:50~58:2900~3200.

[0017] Furthermore, the ZSM-12 pre-crystallized solution is prepared through the following process:

[0018] Sodium and aluminum sources were dissolved in deionized water, then template agent and silicon source were added, and a gel was formed after stirring. The gel was then pre-crystallized in a hydrothermal reactor at 150–190 °C for 6–48 h to obtain a ZSM-12 pre-crystallized solution.

[0019] Furthermore, the sodium source is sodium hydroxide or sodium oxide, the aluminum source is sodium aluminate or aluminum sulfate, the template agent is tetraethylammonium hydroxide, and the silicon source is water glass or tetraethyl orthosilicate. The amounts of sodium source, aluminum source, template agent, and silicon source are determined according to the molar ratio Na2O:Al2O3:SiO2:TEAOH:H2O = 5~16:0.5~1.6:80~130:13~28:1500~3200.

[0020] Furthermore, the amounts of sodium source, aluminum source, template agent and silicon source are determined according to the molar ratio Na2O:Al2O3:SiO2:TEAOH:H2O = 8~12:0.8~1.3:85~112:18~23:1750~2400.

[0021] Furthermore, SAPO-11 is prepared through the following process:

[0022] An aluminum source was dissolved in deionized water, and a phosphorus source, template agent, and silicon source were added. After stirring, a gel was formed and crystallized at 180-220℃ for 3-6 days. After filtration, washing, drying, and calcination, SAPO-11 was obtained.

[0023] Furthermore, the aluminum source is sodium aluminate or aluminum sulfate, the phosphorus source is phosphoric acid or ammonium hydrogen phosphate, the template agent is di-n-propylamine, and the silicon source is water glass or tetraethyl orthosilicate.

[0024] The amounts of aluminum source, phosphorus source, template agent and silicon source are determined according to the molar ratio Al2O3:P2O5:di-n-propylamine:SiO2:H2O = 5~14:5~14:5~14:0.05~0.4:30~50.

[0025] Furthermore, the amounts of aluminum source, phosphorus source, template agent and silicon source are determined according to the molar ratio Al2O3:P2O5:di-n-propylamine:SiO2:H2O = 8~12:8~12:8~12:0.1~0.3:35~45.

[0026] A hydrogen-form ZSM-5 / ZSM-12 / SAPO-11 composite molecular sieve prepared according to the method described above.

[0027] An application of the hydrogen-form ZSM-5 / ZSM-12 / SAPO-11 composite molecular sieve prepared according to the method in the preparation of 2,6-DMN: The hydrogen-form ZSM-5 / ZSM-12 / SAPO-11 composite molecular sieve is uniformly mixed with a binder, extrusion aid, and adhesive solvent, then shaped, dried, and calcined to obtain a catalyst. This catalyst is added to a reactor and reacted under normal pressure. The catalyst is activated under nitrogen protection at a flow rate of 30 mL / min. Then, a mixture of 2-MN, methanol, and solvent in a molar ratio of 1:1:3 is pumped into the reactor at a space velocity of 0.25-1 h⁻¹. -1 The reaction temperature is 350-500℃ and the reaction time is 10h.

[0028] Furthermore, the mass ratio of the hydrogen-form ZSM-5 / ZSM-12 / SAPO-11 composite molecular sieve to boehmite is 1:1; the mass of guar gum accounts for 3% of the total mass of the hydrogen-form ZSM-5 / ZSM-12 / SAPO-11 composite molecular sieve, boehmite, guar gum, and citric acid, and the mass of citric acid accounts for 2% of the total mass of the hydrogen-form ZSM-5 / ZSM-12 / SAPO-11 composite molecular sieve, boehmite, guar gum, and citric acid.

[0029] Compared with the prior art, the present invention has the following beneficial effects:

[0030] Since the composite molecular sieve prepared in this invention belongs to zeolite molecular sieves, which possess unique pore structures, excellent adsorption properties, and abundant surface acid sites, it exhibits good activity in the 2-MN alkylation reaction. Furthermore, due to their different pore structures, zeolite molecular sieves can perform sieving of molecules, selective adsorption, and separation of substances of specific sizes. Among the 10 DMN isomers, β,β-DMN (2,6- / 2,7- / 2,8-DMN) has the smallest molecular size, with actual open pores around 0.60 nm, which is beneficial for β-position shape-selective catalysis and improves its selectivity for 2,6-DMN. ZSM-5, ZSM-12, and SAPO-11 all have diameters around 0.60 nm. Because the relatively weak acidity of SAPO-11 is beneficial for improving the selectivity of 2,6-DMN, while ZSM-5 and ZSM-12 contain more moderately strong acids, and SAPO-11 is relatively weak, this invention improves the selectivity of 2,6-DMN by adding SAPO-11 for co-crystallization to reduce the acidity and acid strength of the composite molecular sieve. Unlike the three-dimensional pore structure of ZSM-5, the ZSM-12 and SAPO-11 used in this invention have a one-dimensional linear pore structure without supercage structure or intersecting pores, allowing unrestricted diffusion of the product, thereby shortening the residence time of the product in the pores, inhibiting coking formation, and improving the anti-coking performance of the composite molecular sieve. 4.2. The diffusion barrier of 2,6-DMN in ZSM-12 is much lower than that of 2,7-DMN, allowing it to diffuse into the product more quickly, thereby increasing the molar ratio of 2,6-DMN to 2,7-DMN in the product, which is beneficial for subsequent separation.

[0031] The ZSM-5 / ZSM-12 / SAPO-11 ternary composite molecular sieve catalyst of this invention has the advantages of high activity, good 2,6-DMN selectivity, and resistance to carbon deposition. Furthermore, it exhibits a high molar ratio of 2,6-DMN to 2,7-DMN in the product, making separation easier and demonstrating excellent overall performance. It shows great promise for industrial application in the alkylation reaction of naphthalene / 2-MN methanol to prepare 2,6-DMN. Detailed Implementation

[0032] The present invention will now be described more fully with reference to embodiments. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a thorough and complete understanding of the disclosure of the present invention.

[0033] The present invention discloses a method for preparing a hydrogen-form ZSM-5 / ZSM-12 / SAPO-11 composite molecular sieve, comprising the following steps:

[0034] By mass fraction, 15-40 parts of ZSM-5 precrystallization solution, 10-35 parts of ZSM-12 precrystallization solution, and 25-75 parts of SAPO-11 are mixed evenly at room temperature, and then co-crystallized in a hydrothermal reactor at 150-200℃ for 1-4 days. The insoluble crystals in the product are filtered out, washed with deionized water at 20-50℃, and then dried at 100-150℃ for 6-24 hours. Finally, it is calcined at 400-600℃ for 3-6 hours to obtain ZSM-5 / ZSM-12 / SAPO-11 composite molecular sieve.

[0035] The ZSM-5 / ZSM-12 / SAPO-11 composite molecular sieve was soaked in a 1 mol / L ammonium nitrate aqueous solution at a solid-liquid ratio of 1:10 at 80℃ for 2 h, and then dried at 120℃ for 4 h. This process was repeated 3 times to obtain ammonium-type zeolite. Finally, the zeolite was calcined at 500-700℃ for 4-6 h to obtain hydrogen-type ZSM-5 / ZSM-12 / SAPO-11 composite molecular sieve.

[0036] The method for preparing ZSM-5 pre-crystallization solution includes the following steps:

[0037] Sodium hydroxide or sodium oxide was used as the sodium source, and sodium aluminate or aluminum sulfate was used as the aluminum source. These solutions were dissolved in deionized water. Then, tetrapropylammonium hydroxide (TPAOH) was added dropwise as a template agent, and water glass or tetraethyl orthosilicate was added as a silicon source. After stirring, a gel was formed. The gel was then pre-crystallized in a hydrothermal reactor at 160–200 °C for 6–24 h to obtain a ZSM-5 pre-crystallized solution. The molar ratio was controlled as follows: Na₂O:Al₂O₃:SiO₂:TPAOH:H₂O = 40–50:0.5–1.6:130–160:45–60:2500–3600.

[0038] Furthermore, sodium hydroxide serves as a sodium source.

[0039] Furthermore, sodium aluminate is used as the aluminum source.

[0040] Furthermore, tetraethyl orthosilicate is used as the silicon source.

[0041] Furthermore, the molar ratio of Na2O:Al2O3:SiO2:TPAOH:H2O is 43-48:0.8-1.2:140-150:50-58:2900-3200.

[0042] The method for preparing ZSM-12 precrystallized solution includes the following steps: Sodium hydroxide or sodium oxide is used as the sodium source, and sodium aluminate or aluminum sulfate is used as the aluminum source. These are dissolved in deionized water. Then, tetraethylammonium hydroxide (TEAOH) as a template agent and water glass or tetraethyl orthosilicate as a silicon source are added dropwise to the solution. After stirring, a gel is formed. The solution is then precrystallized in a hydrothermal reactor at 150–190°C for 6–48 hours to obtain the ZSM-12 precrystallized solution. The molar ratio is controlled as follows: Na₂O:Al₂O₃:SiO₂:TEAOH:H₂O = 5–16:0.5–1.6:80–130:13–28:1500–3200.

[0043] Furthermore, sodium hydroxide serves as a sodium source.

[0044] Furthermore, sodium aluminate is used as the aluminum source.

[0045] Furthermore, tetraethyl orthosilicate is used as the silicon source.

[0046] Furthermore, the molar ratio of Na2O:Al2O3:SiO2:TEAOH:H2O is 8-12:0.8-1.3:85-112:18-23:1750-2400.

[0047] The preparation method of SAPO-11 includes the following steps:

[0048] Sodium aluminate or aluminum sulfate was used as the aluminum source and dissolved in deionized water. Phosphoric acid or ammonium hydrogen phosphate (as the phosphorus source), di-n-propylamine (as the template agent), and water glass or tetraethyl orthosilicate (as the silicon source) were then added dropwise to the solution. After stirring, a gel was formed. The gel was then crystallized in a hydrothermal reactor at 180-220°C for 3-6 days. After filtration, washing, drying, and calcination, SAPO-11 was obtained. The molar ratio was controlled as Al₂O₃:P₂O₅:di-n-propylamine:SiO₂:H₂O = 5-14:5-14:5-14:0.05-0.4:30-50.

[0049] Furthermore, aluminum sulfate is used as an aluminum source.

[0050] Furthermore, phosphoric acid serves as a phosphorus source.

[0051] Furthermore, tetraethyl orthosilicate is used as the silicon source.

[0052] Furthermore, the molar ratio of Al2O3:P2O5:di-n-propylamine:SiO2:H2O = 8~12:8~12:8~12:0.1~0.3:35~45.

[0053] The application of the prepared hydrogen-form ZSM-5 / ZSM-12 / SAPO-11 composite molecular sieve in the preparation of 2,6-DMN involved uniformly mixing the hydrogen-form ZSM-5 / ZSM-12 / SAPO-11 composite molecular sieve with a binder (boehmite), an extrusion aid (guar gum), and a solvent (citric acid), followed by molding, drying, and calcination to obtain a catalyst. This catalyst was then added to a reactor and reacted under normal pressure. The catalyst was activated at 450℃ for 2 hours under nitrogen protection at a flow rate of 30 mL / min. Finally, a mixture of 2-MN, methanol, and a solvent (trimethylbenzene) in a molar ratio of 1:1:3 was pumped into the reactor at a space velocity of 0.25–1 h⁻¹. -1 The reaction temperature was 350-500℃, and the reaction time was 10 hours. The reaction products were collected after condensation and subjected to gas phase analysis for product composition.

[0054] The mass ratio of hydrogen-form ZSM-5 / ZSM-12 / SAPO-11 composite molecular sieve to pseudoboehmite is 1:1; the mass of guar gum powder accounts for 3% of the total mass of hydrogen-form ZSM-5 / ZSM-12 / SAPO-11 composite molecular sieve, pseudoboehmite, guar gum powder, and citric acid, and the mass of citric acid accounts for 2% of the total mass of hydrogen-form ZSM-5 / ZSM-12 / SAPO-11 composite molecular sieve, pseudoboehmite, guar gum powder, and citric acid.

[0055] The initial 2-MN conversion rate was 36.75%-38.58%, the 2,6-DMN selectivity was 56.42%-58.84%, and the molar ratio of 2,6-DMN to 2,7-DMN was 1.73-1.80. After 10 hours of reaction, the 2-MN conversion rate was 21.98%-23.96%, the 2,6-DMN selectivity was 49.06%-50.75%, and the molar ratio of 2,6-DMN to 2,7-DMN was 1.64-1.70, demonstrating good anti-carbon deposition properties.

[0056] The technical solution of the present invention will be described in detail below through specific embodiments:

[0057] Example 1

[0058] This embodiment provides a method for preparing a hydrogen-form ZSM-5 / ZSM-12 / SAPO-11 composite molecular sieve for the alkylation reaction of naphthalene / 2-methylnaphthalene methanol, comprising the following steps:

[0059] By mass fraction, 30 parts of ZSM-5 pre-crystallized solution, 20 parts of ZSM-12 pre-crystallized solution, and 50 parts of SAPO-11 were mixed evenly at room temperature, and then co-crystallized in a hydrothermal reactor at 170℃ for 3 days. Insoluble crystals in the product were filtered out, washed with deionized water at 20-50℃, dried at 105℃ for 12 hours, and then calcined at 500℃ for 4 hours to obtain a ZSM-5 / ZSM-12 / SAPO-11 composite molecular sieve. The ZSM-5 / ZSM-12 / SAPO-11 composite molecular sieve was then soaked in a 1 mol / L ammonium nitrate aqueous solution at a solid-liquid ratio of 1:10 at 80℃ for 2 hours, and then dried at 120℃ for 4 hours. This process was repeated 3 times to obtain ammonium-form zeolite. Finally, it was calcined at 500℃ for 4 hours to obtain the hydrogen-form ZSM-5 / ZSM-12 / SAPO-11 composite molecular sieve.

[0060] The preparation of ZSM-5 precrystallized solution includes the following steps: Sodium hydroxide is used as the sodium source, and sodium aluminate is used as the aluminum source, both dissolved in deionized water. Then, tetrapropylammonium hydroxide (TPAOH) as a template agent and tetraethyl orthosilicate as a silicon source are added dropwise to the solution. After stirring, a gel is formed, and the solution is precrystallized at 170°C for 12 hours in a hydrothermal reactor to obtain the ZSM-5 precrystallized solution. The molar ratio is controlled as Na₂O:Al₂O₃:SiO₂:TPAOH:H₂O = 48:1.1:145:54:3100.

[0061] The preparation of the ZSM-12 precrystallized solution includes the following steps: Sodium hydroxide is used as the sodium source, and sodium aluminate is used as the aluminum source, both dissolved in deionized water. Then, tetraethylammonium hydroxide (TEAOH) as a template agent and tetraethyl orthosilicate as a silicon source are added dropwise to the solution. After stirring, a gel is formed, and the solution is precrystallized at 165°C for 24 hours in a hydrothermal reactor to obtain the ZSM-12 precrystallized solution. The molar ratio is controlled as Na₂O:Al₂O₃:SiO₂:TEAOH:H₂O = 11:1.1:103:21:1950.

[0062] SAPO-11 was prepared by the following steps: Aluminum sulfate was dissolved in deionized water as the aluminum source. Phosphoric acid (as the phosphorus source), di-n-propylamine (as the template agent), and tetraethyl orthosilicate (as the silicon source) were then added dropwise to the solution. After stirring, a gel was formed. The gel was crystallized in a hydrothermal reactor at 190°C for 5 days. The gel was then filtered, washed, dried, and calcined to obtain SAPO-11. The molar ratio was controlled as Al₂O₃:P₂O₅:di-n-propylamine:SiO₂:H₂O = 9.5:9.5:9.5:0.15:40.

[0063] The prepared hydrogen-form ZSM-5 / ZSM-12 / SAPO-11 composite molecular sieve was uniformly mixed with boehmite, guar gum powder, and citric acid, shaped, air-dried at room temperature, then dried at 120℃ for 2 hours, and calcined at 500℃ for 4 hours to obtain the catalyst. The catalyst was sieved to 20–40 mesh and loaded into the central isothermal zone of the reactor, with quartz wool packed both above and below it. The reaction was carried out at atmospheric pressure, and the catalyst was activated at 450℃ for 2 hours under nitrogen protection at a flow rate of 30 mL / min, after which the temperature was lowered to the reaction temperature. The mass ratio of hydrogen-form ZSM-5 / ZSM-12 / SAPO-11 composite molecular sieve to pseudoboehmite is 1:1; the mass of guar gum powder accounts for 3% of the total mass of hydrogen-form ZSM-5 / ZSM-12 / SAPO-11 composite molecular sieve, pseudoboehmite, guar gum powder, and citric acid, and the mass of citric acid accounts for 2% of the total mass of hydrogen-form ZSM-5 / ZSM-12 / SAPO-11 composite molecular sieve, pseudoboehmite, guar gum powder, and citric acid.

[0064] 2-MN, methanol, and solvent in a molar ratio of 1:1:3 were uniformly mixed and pumped into the reactor using a constant flow pump at a space velocity of 0.5 h⁻¹. -1 The reaction temperature was 450℃, and the reaction time was 10 h. The reaction product was collected after condensation and subjected to gas phase analysis for its composition. The results are shown in the table below:

[0065] Table 1 Results of molecular sieve catalytic reaction obtained in Example 1

[0066]

[0067] Example 2

[0068] This embodiment provides a method for preparing a hydrogen-form ZSM-5 / ZSM-12 / SAPO-11 composite molecular sieve for the alkylation reaction of naphthalene / 2-methylnaphthalene methanol, comprising the following steps:

[0069] By mass fraction, 25 parts of ZSM-5 pre-crystallized solution, 15 parts of ZSM-12 pre-crystallized solution, and 60 parts of SAPO-11 were mixed evenly at room temperature, and then co-crystallized in a hydrothermal reactor at 170℃ for 3 days. Insoluble crystals in the product were filtered out, washed with deionized water at 20-50℃, dried at 105℃ for 12 hours, and then calcined at 500℃ for 4 hours to obtain a ZSM-5 / ZSM-12 / SAPO-11 composite molecular sieve. The ZSM-5 / ZSM-12 / SAPO-11 composite molecular sieve was then soaked in a 1 mol / L ammonium nitrate aqueous solution at a solid-liquid ratio of 1:10 at 80℃ for 2 hours, and then dried at 120℃ for 4 hours. This process was repeated 3 times to obtain ammonium-form zeolite. Finally, it was calcined at 500℃ for 4 hours to obtain the hydrogen-form ZSM-5 / ZSM-12 / SAPO-11 composite molecular sieve.

[0070] The preparation of ZSM-5 precrystallized solution includes the following steps: Sodium hydroxide is used as the sodium source, and sodium aluminate is used as the aluminum source, both dissolved in deionized water. Then, tetrapropylammonium hydroxide (TPAOH) as a template agent and tetraethyl orthosilicate as a silicon source are added dropwise to the solution. After stirring, a gel is formed, and the solution is precrystallized at 170°C for 12 hours in a hydrothermal reactor to obtain the ZSM-5 precrystallized solution. The molar ratio is controlled as Na₂O:Al₂O₃:SiO₂:TPAOH:H₂O = 48:1.1:145:54:3100.

[0071] The preparation of the ZSM-12 precrystallized solution includes the following steps: Sodium hydroxide is used as the sodium source, and sodium aluminate is used as the aluminum source, both dissolved in deionized water. Then, tetraethylammonium hydroxide (TEAOH) as a template agent and tetraethyl orthosilicate as a silicon source are added dropwise to the solution. After stirring, a gel is formed, and the solution is precrystallized at 165°C for 24 hours in a hydrothermal reactor to obtain the ZSM-12 precrystallized solution. The molar ratio is controlled as Na₂O:Al₂O₃:SiO₂:TEAOH:H₂O = 11:1.1:103:21:1950.

[0072] SAPO-11 was prepared by the following steps: Aluminum sulfate was dissolved in deionized water as the aluminum source. Phosphoric acid (as the phosphorus source), di-n-propylamine (as the template agent), and tetraethyl orthosilicate (as the silicon source) were then added dropwise to the solution. After stirring, a gel was formed. The gel was crystallized in a hydrothermal reactor at 190°C for 5 days. The gel was then filtered, washed, dried, and calcined to obtain SAPO-11. The molar ratio was controlled as Al₂O₃:P₂O₅:di-n-propylamine:SiO₂:H₂O = 10:10:10:0.2:43.

[0073] The prepared hydrogen-form ZSM-5 / ZSM-12 / SAPO-11 composite molecular sieve was uniformly mixed with boehmite, guar gum powder, and citric acid, shaped, air-dried at room temperature, then dried at 120℃ for 2 hours, and calcined at 500℃ for 4 hours to obtain the catalyst. The catalyst was sieved to 20–40 mesh and loaded into the central isothermal zone of the reactor, with quartz wool packed both above and below it. The reaction was carried out at atmospheric pressure, and the catalyst was activated at 450℃ for 2 hours under nitrogen protection at a flow rate of 30 mL / min, after which the temperature was lowered to the reaction temperature. The mass ratio of hydrogen-form ZSM-5 / ZSM-12 / SAPO-11 composite molecular sieve to pseudoboehmite is 1:1; the mass of guar gum powder accounts for 3% of the total mass of hydrogen-form ZSM-5 / ZSM-12 / SAPO-11 composite molecular sieve, pseudoboehmite, guar gum powder, and citric acid, and the mass of citric acid accounts for 2% of the total mass of hydrogen-form ZSM-5 / ZSM-12 / SAPO-11 composite molecular sieve, pseudoboehmite, guar gum powder, and citric acid.

[0074] 2-MN, methanol, and solvent in a molar ratio of 1:1:3 were uniformly mixed and pumped into the reactor using a constant flow pump at a space velocity of 0.5 h⁻¹. -1 The reaction temperature was 450℃, and the reaction time was 10 h. The reaction product was collected after condensation and subjected to gas phase analysis for its composition. The results are shown in the table below:

[0075] Table 2 Results of molecular sieve catalytic reaction obtained in Example 2

[0076]

[0077]

[0078] Example 3

[0079] This embodiment provides a method for preparing a hydrogen-form ZSM-5 / ZSM-12 / SAPO-11 composite molecular sieve for the alkylation reaction of naphthalene / 2-methylnaphthalene methanol, comprising the following steps:

[0080] By mass fraction, 25 parts of ZSM-5 pre-crystallized solution, 15 parts of ZSM-12 pre-crystallized solution, and 60 parts of SAPO-11 were mixed evenly at room temperature, and then co-crystallized in a hydrothermal reactor at 170℃ for 3 days. Insoluble crystals in the product were filtered out, washed with deionized water at 20-50℃, dried at 105℃ for 12 hours, and then calcined at 500℃ for 4 hours to obtain a ZSM-5 / ZSM-12 / SAPO-11 composite molecular sieve. The ZSM-5 / ZSM-12 / SAPO-11 composite molecular sieve was then soaked in a 1 mol / L ammonium nitrate aqueous solution at a solid-liquid ratio of 1:10 at 80℃ for 2 hours, and then dried at 120℃ for 4 hours. This process was repeated 3 times to obtain ammonium-form zeolite. Finally, it was calcined at 500℃ for 4 hours to obtain the hydrogen-form ZSM-5 / ZSM-12 / SAPO-11 composite molecular sieve.

[0081] The preparation of ZSM-5 precrystallized solution includes the following steps: Sodium hydroxide is used as the sodium source, and sodium aluminate is used as the aluminum source, both dissolved in deionized water. Then, tetrapropylammonium hydroxide (TPAOH) as a template agent and tetraethyl orthosilicate as a silicon source are added dropwise to the solution. After stirring, a gel is formed, and the solution is precrystallized at 170°C for 12 hours in a hydrothermal reactor to obtain the ZSM-5 precrystallized solution. The molar ratio is controlled as Na₂O:Al₂O₃:SiO₂:TPAOH:H₂O = 48:1.1:145:54:3100.

[0082] The preparation of the ZSM-12 precrystallized solution includes the following steps: Sodium hydroxide is used as the sodium source, and sodium aluminate is used as the aluminum source, both dissolved in deionized water. Then, tetraethylammonium hydroxide (TEAOH) as a template agent and tetraethyl orthosilicate as a silicon source are added dropwise to the solution. After stirring, a gel is formed, and the solution is precrystallized at 165°C for 24 hours in a hydrothermal reactor to obtain the ZSM-12 precrystallized solution. The molar ratio is controlled as Na₂O:Al₂O₃:SiO₂:TEAOH:H₂O = 11:1.1:103:21:1950.

[0083] SAPO-11 was prepared by the following steps: Aluminum sulfate was dissolved in deionized water as the aluminum source. Phosphoric acid (as the phosphorus source), di-n-propylamine (as the template agent), and tetraethyl orthosilicate (as the silicon source) were then added dropwise to the solution. After stirring, a gel was formed. The gel was crystallized in a hydrothermal reactor at 200°C for 5 days. The gel was then filtered, washed, dried, and calcined to obtain SAPO-11. The molar ratio was controlled as Al₂O₃:P₂O₅:di-n-propylamine:SiO₂:H₂O = 9.5:9.5:9.5:0.15:40.

[0084] The prepared hydrogen-form ZSM-5 / ZSM-12 / SAPO-11 composite molecular sieve was uniformly mixed with boehmite, guar gum powder, and citric acid, shaped, air-dried at room temperature, then dried at 120℃ for 2 hours, and calcined at 500℃ for 4 hours to obtain the catalyst. The catalyst was sieved to 20–40 mesh and loaded into the central isothermal zone of the reactor, with quartz wool packed both above and below it. The reaction was carried out at atmospheric pressure, and the catalyst was activated at 450℃ for 2 hours under nitrogen protection at a flow rate of 30 mL / min, after which the temperature was lowered to the reaction temperature.

[0085] The mass ratio of hydrogen-form ZSM-5 / ZSM-12 / SAPO-11 composite molecular sieve to pseudoboehmite is 1:1; the mass of guar gum powder accounts for 3% of the total mass of hydrogen-form ZSM-5 / ZSM-12 / SAPO-11 composite molecular sieve, pseudoboehmite, guar gum powder, and citric acid, and the mass of citric acid accounts for 2% of the total mass of hydrogen-form ZSM-5 / ZSM-12 / SAPO-11 composite molecular sieve, pseudoboehmite, guar gum powder, and citric acid.

[0086] 2-MN, methanol, and solvent in a molar ratio of 1:1:3 were uniformly mixed and pumped into the reactor using a constant flow pump at a space velocity of 0.5 h⁻¹. -1 The reaction temperature was 450℃, and the reaction time was 10 h. The reaction product was collected after condensation and subjected to gas phase analysis for its composition. The results are shown in the table below:

[0087] Table 3 Results of molecular sieve catalytic reaction obtained in Example 3

[0088]

[0089] Example 4

[0090] This embodiment provides a method for preparing a hydrogen-form ZSM-5 / ZSM-12 / SAPO-11 composite molecular sieve for the alkylation reaction of naphthalene / 2-methylnaphthalene methanol, comprising the following steps:

[0091] By mass fraction, 25 parts of ZSM-5 pre-crystallized solution, 15 parts of ZSM-12 pre-crystallized solution, and 60 parts of SAPO-11 were mixed evenly at room temperature, and then co-crystallized in a hydrothermal reactor at 170℃ for 3 days. Insoluble crystals in the product were filtered out, washed with deionized water at 20-50℃, dried at 105℃ for 12 hours, and then calcined at 500℃ for 4 hours to obtain a ZSM-5 / ZSM-12 / SAPO-11 composite molecular sieve. The ZSM-5 / ZSM-12 / SAPO-11 composite molecular sieve was then soaked in a 1 mol / L ammonium nitrate aqueous solution at a solid-liquid ratio of 1:10 at 80℃ for 2 hours, and then dried at 120℃ for 4 hours. This process was repeated 3 times to obtain ammonium-form zeolite. Finally, it was calcined at 500℃ for 4 hours to obtain the hydrogen-form ZSM-5 / ZSM-12 / SAPO-11 composite molecular sieve.

[0092] The preparation of ZSM-5 precrystallized solution includes the following steps: Sodium hydroxide is used as the sodium source, and sodium aluminate is used as the aluminum source, both dissolved in deionized water. Then, tetrapropylammonium hydroxide (TPAOH) as a template agent and tetraethyl orthosilicate as a silicon source are added dropwise to the solution. After stirring, a gel is formed, and the solution is precrystallized at 170°C for 12 hours in a hydrothermal reactor to obtain the ZSM-5 precrystallized solution. The molar ratio is controlled as Na₂O:Al₂O₃:SiO₂:TPAOH:H₂O = 48:1.1:145:54:3100.

[0093] The preparation of the ZSM-12 precrystallized solution includes the following steps: Sodium hydroxide is used as the sodium source, and sodium aluminate is used as the aluminum source, both dissolved in deionized water. Then, tetraethylammonium hydroxide (TEAOH) as a template agent and tetraethyl orthosilicate as a silicon source are added dropwise to the solution. After stirring, a gel is formed, and the solution is precrystallized at 165°C for 24 hours in a hydrothermal reactor to obtain the ZSM-12 precrystallized solution. The molar ratio is controlled as Na₂O:Al₂O₃:SiO₂:TEAOH:H₂O = 11:1.1:103:21:1950.

[0094] SAPO-11 was prepared by the following steps: Aluminum sulfate was dissolved in deionized water as the aluminum source. Phosphoric acid (as the phosphorus source), di-n-propylamine (as the template agent), and tetraethyl orthosilicate (as the silicon source) were then added dropwise to the solution. After stirring, a gel was formed. The gel was crystallized at 190°C for 4 days in a hydrothermal reactor. The gel was then filtered, washed, dried, and calcined to obtain SAPO-11. The molar ratio was controlled as Al₂O₃:P₂O₅:di-n-propylamine:SiO₂:H₂O = 9.5:9.5:9.5:0.15:40.

[0095] The prepared hydrogen-form ZSM-5 / ZSM-12 / SAPO-11 composite molecular sieve was uniformly mixed with boehmite, guar gum powder, and citric acid, shaped, air-dried at room temperature, then dried at 120℃ for 2 hours, and calcined at 500℃ for 4 hours to obtain the catalyst. The catalyst was sieved to 20–40 mesh and loaded into the central isothermal zone of the reactor, with quartz wool packed both above and below it. The reaction was carried out at atmospheric pressure, and the catalyst was activated at 450℃ for 2 hours under nitrogen protection at a flow rate of 30 mL / min, after which the temperature was lowered to the reaction temperature.

[0096] The mass ratio of hydrogen-form ZSM-5 / ZSM-12 / SAPO-11 composite molecular sieve to pseudoboehmite is 1:1; the mass of guar gum powder accounts for 3% of the total mass of hydrogen-form ZSM-5 / ZSM-12 / SAPO-11 composite molecular sieve, pseudoboehmite, guar gum powder, and citric acid, and the mass of citric acid accounts for 2% of the total mass of hydrogen-form ZSM-5 / ZSM-12 / SAPO-11 composite molecular sieve, pseudoboehmite, guar gum powder, and citric acid.

[0097] 2-MN, methanol, and solvent in a molar ratio of 1:1:3 were uniformly mixed and pumped into the reactor using a constant flow pump at a space velocity of 0.5 h⁻¹. -1 The reaction temperature was 450℃, and the reaction time was 10 h. The reaction product was collected after condensation and subjected to gas phase analysis for its composition. The results are shown in the table below:

[0098] Table 4. Results of molecular sieve catalytic reaction obtained in Example 4

[0099]

[0100]

[0101] Example 5

[0102] This embodiment provides a method for preparing a hydrogen-form ZSM-5 / ZSM-12 / SAPO-11 composite molecular sieve for the alkylation reaction of naphthalene / 2-methylnaphthalene methanol, comprising the following steps:

[0103] By mass fraction, 25 parts of ZSM-5 pre-crystallized solution, 15 parts of ZSM-12 pre-crystallized solution, and 60 parts of SAPO-11 were mixed evenly at room temperature, and then co-crystallized in a hydrothermal reactor at 170℃ for 3 days. Insoluble crystals in the product were filtered out, washed with deionized water at 20-50℃, dried at 105℃ for 12 hours, and then calcined at 500℃ for 4 hours to obtain a ZSM-5 / ZSM-12 / SAPO-11 composite molecular sieve. The ZSM-5 / ZSM-12 / SAPO-11 composite molecular sieve was then soaked in a 1 mol / L ammonium nitrate aqueous solution at a solid-liquid ratio of 1:10 at 80℃ for 2 hours, and then dried at 120℃ for 4 hours. This process was repeated 3 times to obtain ammonium-form zeolite. Finally, it was calcined at 500℃ for 4 hours to obtain the hydrogen-form ZSM-5 / ZSM-12 / SAPO-11 composite molecular sieve.

[0104] The preparation of the ZSM-5 precrystallized solution includes the following steps: Sodium hydroxide is used as the sodium source, and sodium aluminate is used as the aluminum source, both dissolved in deionized water. Then, tetrapropylammonium hydroxide (TPAOH) as a template agent and tetraethyl orthosilicate as a silicon source are added dropwise to the solution. After stirring, a gel is formed, and the solution is precrystallized at 170°C for 12 hours in a hydrothermal reactor to obtain the ZSM-5 precrystallized solution. The molar ratio is controlled as Na₂O:Al₂O₃:SiO₂:TPAOH:H₂O = 45:1:150:53:3000.

[0105] The preparation of the ZSM-12 precrystallized solution includes the following steps: Sodium hydroxide is used as the sodium source, and sodium aluminate is used as the aluminum source, both dissolved in deionized water. Then, tetraethylammonium hydroxide (TEAOH) as a template agent and tetraethyl orthosilicate as a silicon source are added dropwise to the solution. After stirring, a gel is formed, and the solution is precrystallized at 165°C for 24 hours in a hydrothermal reactor to obtain the ZSM-12 precrystallized solution. The molar ratio is controlled as Na₂O:Al₂O₃:SiO₂:TEAOH:H₂O = 11:1.1:103:21:1950.

[0106] SAPO-11 was prepared by the following steps: Aluminum sulfate was dissolved in deionized water as the aluminum source. Phosphoric acid (as the phosphorus source), di-n-propylamine (as the template agent), and tetraethyl orthosilicate (as the silicon source) were then added dropwise to the solution. After stirring, a gel was formed. The gel was crystallized in a hydrothermal reactor at 190°C for 5 days. The gel was then filtered, washed, dried, and calcined to obtain SAPO-11. The molar ratio was controlled as Al₂O₃:P₂O₅:di-n-propylamine:SiO₂:H₂O = 9.5:9.5:9.5:0.15:40.

[0107] The prepared hydrogen-form ZSM-5 / ZSM-12 / SAPO-11 composite molecular sieve was uniformly mixed with boehmite, guar gum powder, and citric acid, shaped, air-dried at room temperature, then dried at 120℃ for 2 hours, and calcined at 500℃ for 4 hours to obtain the catalyst. The catalyst was sieved to 20–40 mesh and loaded into the central isothermal zone of the reactor, with quartz wool packed both above and below it. The reaction was carried out at atmospheric pressure, and the catalyst was activated at 450℃ for 2 hours under nitrogen protection at a flow rate of 30 mL / min, after which the temperature was lowered to the reaction temperature.

[0108] The mass ratio of hydrogen-form ZSM-5 / ZSM-12 / SAPO-11 composite molecular sieve to pseudoboehmite is 1:1; the mass of guar gum powder accounts for 3% of the total mass of hydrogen-form ZSM-5 / ZSM-12 / SAPO-11 composite molecular sieve, pseudoboehmite, guar gum powder, and citric acid, and the mass of citric acid accounts for 2% of the total mass of hydrogen-form ZSM-5 / ZSM-12 / SAPO-11 composite molecular sieve, pseudoboehmite, guar gum powder, and citric acid.

[0109] 2-MN, methanol, and solvent in a molar ratio of 1:1:3 were uniformly mixed and pumped into the reactor using a constant flow pump at a space velocity of 0.5 h⁻¹. -1 The reaction temperature was 450℃, and the reaction time was 10 h. The reaction product was collected after condensation and subjected to gas phase analysis for its composition. The results are shown in the table below:

[0110] Table 5. Results of the molecular sieve catalytic reaction obtained in Example 5

[0111]

[0112] Example 6

[0113] This embodiment provides a method for preparing a hydrogen-form ZSM-5 / ZSM-12 / SAPO-11 composite molecular sieve for the alkylation reaction of naphthalene / 2-methylnaphthalene methanol, comprising the following steps:

[0114] By mass fraction, 25 parts of ZSM-5 pre-crystallized solution, 15 parts of ZSM-12 pre-crystallized solution, and 60 parts of SAPO-11 were mixed evenly at room temperature, and then co-crystallized in a hydrothermal reactor at 170℃ for 3 days. Insoluble crystals in the product were filtered out, washed with deionized water at 20-50℃, dried at 105℃ for 12 hours, and then calcined at 500℃ for 4 hours to obtain a ZSM-5 / ZSM-12 / SAPO-11 composite molecular sieve. The ZSM-5 / ZSM-12 / SAPO-11 composite molecular sieve was then soaked in a 1 mol / L ammonium nitrate aqueous solution at a solid-liquid ratio of 1:10 at 80℃ for 2 hours, and then dried at 120℃ for 4 hours. This process was repeated 3 times to obtain ammonium-form zeolite. Finally, it was calcined at 500℃ for 4 hours to obtain the hydrogen-form ZSM-5 / ZSM-12 / SAPO-11 composite molecular sieve.

[0115] The preparation of ZSM-5 precrystallized solution includes the following steps: Sodium hydroxide is used as the sodium source, and sodium aluminate is used as the aluminum source, both dissolved in deionized water. Then, tetrapropylammonium hydroxide (TPAOH) as a template agent and tetraethyl orthosilicate as a silicon source are added dropwise to the solution. After stirring, a gel is formed, and the solution is precrystallized at 170°C for 12 hours in a hydrothermal reactor to obtain the ZSM-5 precrystallized solution. The molar ratio is controlled as Na₂O:Al₂O₃:SiO₂:TPAOH:H₂O = 48:1.1:145:54:3100.

[0116] The preparation of ZSM-12 precrystallized solution includes the following steps: Sodium hydroxide is used as the sodium source, and sodium aluminate is used as the aluminum source, both dissolved in deionized water. Then, tetraethylammonium hydroxide (TEAOH) as a template agent and tetraethyl orthosilicate as a silicon source are added dropwise to the solution. After stirring, a gel is formed, and the solution is precrystallized at 165℃ for 24 hours in a hydrothermal reactor to obtain the ZSM-12 precrystallized solution. The molar ratio is controlled as Na₂O:Al₂O₃:SiO₂:TEAOH:H₂O = 10:1:100:20:2000.

[0117] SAPO-11 was prepared by the following steps: Aluminum sulfate was dissolved in deionized water as the aluminum source. Phosphoric acid (as the phosphorus source), di-n-propylamine (as the template agent), and tetraethyl orthosilicate (as the silicon source) were then added dropwise to the solution. After stirring, a gel was formed. The gel was crystallized in a hydrothermal reactor at 190°C for 5 days. The gel was then filtered, washed, dried, and calcined to obtain SAPO-11. The molar ratio was controlled as Al₂O₃:P₂O₅:di-n-propylamine:SiO₂:H₂O = 9.5:9.5:9.5:0.15:40.

[0118] The prepared hydrogen-form ZSM-5 / ZSM-12 / SAPO-11 composite molecular sieve was uniformly mixed with boehmite, guar gum powder, and citric acid, shaped, air-dried at room temperature, then dried at 120℃ for 2 hours, and calcined at 500℃ for 4 hours to obtain the catalyst. The catalyst was sieved to 20–40 mesh and loaded into the central isothermal zone of the reactor, with quartz wool packed both above and below it. The reaction was carried out at atmospheric pressure, and the catalyst was activated at 450℃ for 2 hours under nitrogen protection at a flow rate of 30 mL / min, after which the temperature was lowered to the reaction temperature.

[0119] The mass ratio of hydrogen-form ZSM-5 / ZSM-12 / SAPO-11 composite molecular sieve to pseudoboehmite is 1:1; the mass of guar gum powder accounts for 3% of the total mass of hydrogen-form ZSM-5 / ZSM-12 / SAPO-11 composite molecular sieve, pseudoboehmite, guar gum powder, and citric acid, and the mass of citric acid accounts for 2% of the total mass of hydrogen-form ZSM-5 / ZSM-12 / SAPO-11 composite molecular sieve, pseudoboehmite, guar gum powder, and citric acid.

[0120] 2-MN, methanol, and solvent in a molar ratio of 1:1:3 were uniformly mixed and pumped into the reactor using a constant flow pump at a space velocity of 0.5 h⁻¹. -1 The reaction temperature was 450℃, and the reaction time was 10 h. The reaction product was collected after condensation and subjected to gas phase analysis for its composition. The results are shown in the table below:

[0121] Table 6 Results of molecular sieve catalytic reaction obtained in Example 6

[0122]

[0123] Example 7

[0124] This embodiment provides a method for preparing a hydrogen-form ZSM-5 / ZSM-12 / SAPO-11 composite molecular sieve for the alkylation reaction of naphthalene / 2-methylnaphthalene methanol, comprising the following steps:

[0125] By mass fraction, 25 parts of ZSM-5 pre-crystallized solution, 15 parts of ZSM-12 pre-crystallized solution, and 60 parts of SAPO-11 were mixed evenly at room temperature, and then co-crystallized in a hydrothermal reactor at 170℃ for 3 days. Insoluble crystals in the product were filtered out, washed with deionized water at 20-50℃, dried at 105℃ for 12 hours, and then calcined at 500℃ for 4 hours to obtain a ZSM-5 / ZSM-12 / SAPO-11 composite molecular sieve. The ZSM-5 / ZSM-12 / SAPO-11 composite molecular sieve was then soaked in a 1 mol / L ammonium nitrate aqueous solution at a solid-liquid ratio of 1:10 at 80℃ for 2 hours, and then dried at 120℃ for 4 hours. This process was repeated 3 times to obtain ammonium-form zeolite. Finally, it was calcined at 500℃ for 4 hours to obtain the hydrogen-form ZSM-5 / ZSM-12 / SAPO-11 composite molecular sieve.

[0126] The preparation of ZSM-5 precrystallized solution includes the following steps: Sodium hydroxide is used as the sodium source, and sodium aluminate is used as the aluminum source, both dissolved in deionized water. Then, tetrapropylammonium hydroxide (TPAOH) as a template agent and tetraethyl orthosilicate as a silicon source are added dropwise to the solution. After stirring, a gel is formed, and the solution is precrystallized at 180℃ for 6 hours in a hydrothermal reactor to obtain the ZSM-5 precrystallized solution. The molar ratio is controlled as Na₂O:Al₂O₃:SiO₂:TPAOH:H₂O = 48:1.1:145:54:3100.

[0127] The preparation of the ZSM-12 precrystallized solution includes the following steps: Sodium hydroxide is used as the sodium source, and sodium aluminate is used as the aluminum source, both dissolved in deionized water. Then, tetraethylammonium hydroxide (TEAOH) as a template agent and tetraethyl orthosilicate as a silicon source are added dropwise to the solution. After stirring, a gel is formed, and the solution is precrystallized at 165°C for 24 hours in a hydrothermal reactor to obtain the ZSM-12 precrystallized solution. The molar ratio is controlled as Na₂O:Al₂O₃:SiO₂:TEAOH:H₂O = 11:1.1:103:21:1950.

[0128] SAPO-11 was prepared by the following steps: Aluminum sulfate was dissolved in deionized water as the aluminum source. Phosphoric acid (as the phosphorus source), di-n-propylamine (as the template agent), and tetraethyl orthosilicate (as the silicon source) were then added dropwise to the solution. After stirring, a gel was formed. The gel was crystallized in a hydrothermal reactor at 190°C for 5 days. The gel was then filtered, washed, dried, and calcined to obtain SAPO-11. The molar ratio was controlled as Al₂O₃:P₂O₅:di-n-propylamine:SiO₂:H₂O = 9.5:9.5:9.5:0.15:40.

[0129] The prepared hydrogen-form ZSM-5 / ZSM-12 / SAPO-11 composite molecular sieve was uniformly mixed with boehmite, guar gum powder, and citric acid, shaped, air-dried at room temperature, then dried at 120℃ for 2 hours, and calcined at 500℃ for 4 hours to obtain the catalyst. The catalyst was sieved to 20–40 mesh and loaded into the central isothermal zone of the reactor, with quartz wool packed both above and below it. The reaction was carried out at atmospheric pressure, and the catalyst was activated at 450℃ for 2 hours under nitrogen protection at a flow rate of 30 mL / min, after which the temperature was lowered to the reaction temperature.

[0130] The mass ratio of hydrogen-form ZSM-5 / ZSM-12 / SAPO-11 composite molecular sieve to pseudoboehmite is 1:1; the mass of guar gum powder accounts for 3% of the total mass of hydrogen-form ZSM-5 / ZSM-12 / SAPO-11 composite molecular sieve, pseudoboehmite, guar gum powder, and citric acid, and the mass of citric acid accounts for 2% of the total mass of hydrogen-form ZSM-5 / ZSM-12 / SAPO-11 composite molecular sieve, pseudoboehmite, guar gum powder, and citric acid.

[0131] 2-MN, methanol, and solvent in a molar ratio of 1:1:3 were uniformly mixed and pumped into the reactor using a constant flow pump at a space velocity of 0.5 h⁻¹. -1 The reaction temperature was 450℃, and the reaction time was 10 h. The reaction product was collected after condensation and subjected to gas phase analysis for its composition. The results are shown in the table below:

[0132] Table 7 Results of molecular sieve catalytic reaction obtained in Example 7

[0133]

[0134] Example 8

[0135] This embodiment provides a method for preparing a hydrogen-form ZSM-5 / ZSM-12 / SAPO-11 composite molecular sieve for the alkylation reaction of naphthalene / 2-methylnaphthalene methanol, comprising the following steps:

[0136] By mass fraction, 25 parts of ZSM-5 pre-crystallized solution, 15 parts of ZSM-12 pre-crystallized solution, and 60 parts of SAPO-11 were mixed evenly at room temperature, and then co-crystallized in a hydrothermal reactor at 170℃ for 3 days. Insoluble crystals in the product were filtered out, washed with deionized water at 20-50℃, dried at 105℃ for 12 hours, and then calcined at 500℃ for 4 hours to obtain a ZSM-5 / ZSM-12 / SAPO-11 composite molecular sieve. The ZSM-5 / ZSM-12 / SAPO-11 composite molecular sieve was then soaked in a 1 mol / L ammonium nitrate aqueous solution at a solid-liquid ratio of 1:10 at 80℃ for 2 hours, and then dried at 120℃ for 4 hours. This process was repeated 3 times to obtain ammonium-form zeolite. Finally, it was calcined at 500℃ for 4 hours to obtain the hydrogen-form ZSM-5 / ZSM-12 / SAPO-11 composite molecular sieve.

[0137] The preparation of ZSM-5 precrystallized solution includes the following steps: Sodium hydroxide is used as the sodium source, and sodium aluminate is used as the aluminum source, both dissolved in deionized water. Then, tetrapropylammonium hydroxide (TPAOH) as a template agent and tetraethyl orthosilicate as a silicon source are added dropwise to the solution. After stirring, a gel is formed, and the solution is precrystallized at 170°C for 12 hours in a hydrothermal reactor to obtain the ZSM-5 precrystallized solution. The molar ratio is controlled as Na₂O:Al₂O₃:SiO₂:TPAOH:H₂O = 48:1.1:145:54:3100.

[0138] The preparation of ZSM-12 precrystallized solution includes the following steps: Sodium hydroxide is used as the sodium source, and sodium aluminate is used as the aluminum source, both dissolved in deionized water. Then, tetraethylammonium hydroxide (TEAOH) as a template agent and tetraethyl orthosilicate as a silicon source are added dropwise to the solution. After stirring, a gel is formed, and the solution is precrystallized at 170°C for 48 hours in a hydrothermal reactor to obtain the ZSM-12 precrystallized solution. The molar ratio is controlled as Na₂O:Al₂O₃:SiO₂:TEAOH:H₂O = 11:1.1:103:21:1950.

[0139] SAPO-11 was prepared by the following steps: Aluminum sulfate was dissolved in deionized water as the aluminum source. Phosphoric acid (as the phosphorus source), di-n-propylamine (as the template agent), and tetraethyl orthosilicate (as the silicon source) were then added dropwise to the solution. After stirring, a gel was formed. The gel was crystallized in a hydrothermal reactor at 190°C for 5 days. The gel was then filtered, washed, dried, and calcined to obtain SAPO-11. The molar ratio was controlled as Al₂O₃:P₂O₅:di-n-propylamine:SiO₂:H₂O = 9.5:9.5:9.5:0.15:40.

[0140] The prepared hydrogen-form ZSM-5 / ZSM-12 / SAPO-11 composite molecular sieve was uniformly mixed with boehmite, guar gum powder, and citric acid, shaped, air-dried at room temperature, then dried at 120℃ for 2 hours, and calcined at 500℃ for 4 hours to obtain the catalyst. The catalyst was sieved to 20–40 mesh and loaded into the central isothermal zone of the reactor, with quartz wool packed both above and below it. The reaction was carried out at atmospheric pressure, and the catalyst was activated at 450℃ for 2 hours under nitrogen protection at a flow rate of 30 mL / min, after which the temperature was lowered to the reaction temperature.

[0141] The mass ratio of hydrogen-form ZSM-5 / ZSM-12 / SAPO-11 composite molecular sieve to pseudoboehmite is 1:1; the mass of guar gum powder accounts for 3% of the total mass of hydrogen-form ZSM-5 / ZSM-12 / SAPO-11 composite molecular sieve, pseudoboehmite, guar gum powder, and citric acid, and the mass of citric acid accounts for 2% of the total mass of hydrogen-form ZSM-5 / ZSM-12 / SAPO-11 composite molecular sieve, pseudoboehmite, guar gum powder, and citric acid.

[0142] 2-MN, methanol, and solvent in a molar ratio of 1:1:3 were uniformly mixed and pumped into the reactor using a constant flow pump at a space velocity of 0.5 h⁻¹. -1 The reaction temperature was 450℃, and the reaction time was 10 h. The reaction product was collected after condensation and subjected to gas phase analysis for its composition. The results are shown in the table below:

[0143] Table 8 Results of molecular sieve catalytic reaction obtained in Example 8

[0144]

[0145] Example 9

[0146] This embodiment provides a method for preparing a hydrogen-form ZSM-5 / ZSM-12 / SAPO-11 composite molecular sieve for the alkylation reaction of naphthalene / 2-methylnaphthalene methanol, comprising the following steps:

[0147] By mass fraction, 25 parts of ZSM-5 pre-crystallized solution, 15 parts of ZSM-12 pre-crystallized solution, and 60 parts of SAPO-11 were mixed evenly at room temperature, and then co-crystallized in a hydrothermal reactor at 180℃ for 3 days. Insoluble crystals in the product were filtered out, washed with deionized water at 20-50℃, dried at 105℃ for 12 hours, and then calcined at 500℃ for 4 hours to obtain a ZSM-5 / ZSM-12 / SAPO-11 composite molecular sieve. The ZSM-5 / ZSM-12 / SAPO-11 composite molecular sieve was then soaked in a 1 mol / L ammonium nitrate aqueous solution at a solid-liquid ratio of 1:10 at 80℃ for 2 hours, and then dried at 120℃ for 4 hours. This process was repeated three times to obtain ammonium-form zeolite. Finally, it was calcined at 500℃ for 4 hours to obtain the hydrogen-form ZSM-5 / ZSM-12 / SAPO-11 composite molecular sieve.

[0148] The preparation of ZSM-5 precrystallized solution includes the following steps: Sodium hydroxide is used as the sodium source, and sodium aluminate is used as the aluminum source, both dissolved in deionized water. Then, tetrapropylammonium hydroxide (TPAOH) as a template agent and tetraethyl orthosilicate as a silicon source are added dropwise to the solution. After stirring, a gel is formed, and the solution is precrystallized at 170°C for 12 hours in a hydrothermal reactor to obtain the ZSM-5 precrystallized solution. The molar ratio is controlled as Na₂O:Al₂O₃:SiO₂:TPAOH:H₂O = 48:1.1:145:54:3100.

[0149] The preparation of the ZSM-12 precrystallized solution includes the following steps: Sodium hydroxide is used as the sodium source, and sodium aluminate is used as the aluminum source, both dissolved in deionized water. Then, tetraethylammonium hydroxide (TEAOH) as a template agent and tetraethyl orthosilicate as a silicon source are added dropwise to the solution. After stirring, a gel is formed, and the solution is precrystallized at 165°C for 24 hours in a hydrothermal reactor to obtain the ZSM-12 precrystallized solution. The molar ratio is controlled as Na₂O:Al₂O₃:SiO₂:TEAOH:H₂O = 11:1.1:103:21:1950.

[0150] SAPO-11 was prepared by the following steps: Aluminum sulfate was dissolved in deionized water as the aluminum source. Phosphoric acid (as the phosphorus source), di-n-propylamine (as the template agent), and tetraethyl orthosilicate (as the silicon source) were then added dropwise to the solution. After stirring, a gel was formed. The gel was crystallized in a hydrothermal reactor at 190°C for 5 days. The gel was then filtered, washed, dried, and calcined to obtain SAPO-11. The molar ratio was controlled as Al₂O₃:P₂O₅:di-n-propylamine:SiO₂:H₂O = 9.5:9.5:9.5:0.15:40.

[0151] The prepared hydrogen-form ZSM-5 / ZSM-12 / SAPO-11 composite molecular sieve was uniformly mixed with boehmite, guar gum powder, and citric acid, shaped, air-dried at room temperature, then dried at 120℃ for 2 hours, and calcined at 500℃ for 4 hours to obtain the catalyst. The catalyst was sieved to 20–40 mesh and loaded into the central isothermal zone of the reactor, with quartz wool packed both above and below it. The reaction was carried out at atmospheric pressure, and the catalyst was activated at 450℃ for 2 hours under nitrogen protection at a flow rate of 30 mL / min, after which the temperature was lowered to the reaction temperature.

[0152] The mass ratio of hydrogen-form ZSM-5 / ZSM-12 / SAPO-11 composite molecular sieve to pseudoboehmite is 1:1; the mass of guar gum powder accounts for 3% of the total mass of hydrogen-form ZSM-5 / ZSM-12 / SAPO-11 composite molecular sieve, pseudoboehmite, guar gum powder, and citric acid, and the mass of citric acid accounts for 2% of the total mass of hydrogen-form ZSM-5 / ZSM-12 / SAPO-11 composite molecular sieve, pseudoboehmite, guar gum powder, and citric acid.

[0153] 2-MN, methanol, and solvent in a molar ratio of 1:1:3 were uniformly mixed and pumped into the reactor using a constant flow pump at a space velocity of 0.5 h⁻¹. -1 The reaction temperature was 450℃, and the reaction time was 10 h. The reaction product was collected after condensation and subjected to gas phase analysis for its composition. The results are shown in the table below:

[0154] Table 9 Results of molecular sieve catalytic reaction obtained in Example 9

[0155]

[0156] Example 10

[0157] This embodiment provides a method for preparing a hydrogen-form ZSM-5 / ZSM-12 / SAPO-11 composite molecular sieve for the alkylation reaction of naphthalene / 2-methylnaphthalene methanol, comprising the following steps:

[0158] By mass fraction, 15 parts of ZSM-5 pre-crystallized solution, 10 parts of ZSM-12 pre-crystallized solution, and 25 parts of SAPO-11 were mixed evenly at room temperature, and then co-crystallized in a hydrothermal reactor at 50℃ for 4 days. Insoluble crystals in the product were filtered out, washed with deionized water at 20℃, and then dried at 100℃ for 24 hours. Finally, it was calcined at 400℃ for 6 hours to obtain a ZSM-5 / ZSM-12 / SAPO-11 composite molecular sieve. The ZSM-5 / ZSM-12 / SAPO-11 composite molecular sieve was then soaked in a 1 mol / L ammonium nitrate aqueous solution at a solid-liquid ratio of 1:10 at 80℃ for 2 hours, and then dried at 120℃ for 4 hours. This process was repeated three times to obtain ammonium-form zeolite. Finally, it was calcined at 500℃ for 6 hours to obtain the hydrogen-form ZSM-5 / ZSM-12 / SAPO-11 composite molecular sieve.

[0159] The preparation of ZSM-5 precrystallized solution includes the following steps: Sodium hydroxide is used as the sodium source, and sodium aluminate is used as the aluminum source, both dissolved in deionized water. Then, tetrapropylammonium hydroxide (TPAOH) as a template agent and tetraethyl orthosilicate as a silicon source are added dropwise to the solution. After stirring, a gel is formed, and the solution is precrystallized at 160℃ for 24 hours in a hydrothermal reactor to obtain the ZSM-5 precrystallized solution. The molar ratio is controlled as Na₂O:Al₂O₃:SiO₂:TPAOH:H₂O = 40:0.5:130:45:2500.

[0160] The preparation of ZSM-12 precrystallized solution includes the following steps: Sodium hydroxide is used as the sodium source, and sodium aluminate is used as the aluminum source, both dissolved in deionized water. Then, tetraethylammonium hydroxide (TEAOH) as a template agent and tetraethyl orthosilicate as a silicon source are added dropwise to the solution. After stirring, a gel is formed, and the solution is precrystallized at 150°C for 48 hours in a hydrothermal reactor to obtain the ZSM-12 precrystallized solution. The molar ratio is controlled as Na₂O:Al₂O₃:SiO₂:TEAOH:H₂O = 5:0.5:80:28:3200.

[0161] SAPO-11 was prepared by the following steps: Aluminum sulfate was dissolved in deionized water as the aluminum source. Phosphoric acid (as the phosphorus source), di-n-propylamine (as the template agent), and tetraethyl orthosilicate (as the silicon source) were then added dropwise to the solution. After stirring, a gel was formed. The gel was crystallized at 180°C for 6 days in a hydrothermal reactor. The gel was then filtered, washed, dried, and calcined to obtain SAPO-11. The molar ratio was controlled as Al₂O₃:P₂O₅:di-n-propylamine:SiO₂:H₂O = 5:5:5:0.05:50.

[0162] The prepared hydrogen-form ZSM-5 / ZSM-12 / SAPO-11 composite molecular sieve was uniformly mixed with boehmite, guar gum powder, and citric acid, shaped, air-dried at room temperature, then dried at 120℃ for 2 hours, and calcined at 500℃ for 4 hours to obtain the catalyst. The catalyst was sieved to 20–40 mesh and loaded into the central isothermal zone of the reactor, with quartz wool packed both above and below it. The reaction was carried out at atmospheric pressure, and the catalyst was activated at 450℃ for 2 hours under nitrogen protection at a flow rate of 30 mL / min, after which the temperature was lowered to the reaction temperature. The mass ratio of hydrogen-form ZSM-5 / ZSM-12 / SAPO-11 composite molecular sieve to pseudoboehmite is 1:1; the mass of guar gum powder accounts for 3% of the total mass of hydrogen-form ZSM-5 / ZSM-12 / SAPO-11 composite molecular sieve, pseudoboehmite, guar gum powder, and citric acid, and the mass of citric acid accounts for 2% of the total mass of hydrogen-form ZSM-5 / ZSM-12 / SAPO-11 composite molecular sieve, pseudoboehmite, guar gum powder, and citric acid.

[0163] 2-MN, methanol, and solvent were uniformly mixed in a molar ratio of 1:1:3 and then pumped into the reactor using a constant flow pump at a space velocity of 0.25 h⁻¹. -1 The reaction temperature was 350℃, and the reaction time was 10 h. The reaction product was collected after condensation and subjected to gas phase analysis for its composition. The results are shown in the table below:

[0164] Table 10 Results of the molecular sieve catalytic reaction obtained in Example 10

[0165]

[0166] Example 11

[0167] This embodiment provides a method for preparing a hydrogen-form ZSM-5 / ZSM-12 / SAPO-11 composite molecular sieve for the alkylation reaction of naphthalene / 2-methylnaphthalene methanol, comprising the following steps:

[0168] By mass fraction, 20 parts of ZSM-5 pre-crystallized solution, 35 parts of ZSM-12 pre-crystallized solution, and 40 parts of SAPO-11 were mixed evenly at room temperature, and then co-crystallized in a hydrothermal reactor at 200℃ for 1 day. The insoluble crystals in the product were filtered out, washed with deionized water at 30℃, and then dried at 120℃ for 17 hours. Finally, it was calcined at 500℃ for 4 hours to obtain a ZSM-5 / ZSM-12 / SAPO-11 composite molecular sieve. The ZSM-5 / ZSM-12 / SAPO-11 composite molecular sieve was then soaked in a 1 mol / L ammonium nitrate aqueous solution at a solid-liquid ratio of 1:10 at 80℃ for 2 hours, and then dried at 120℃ for 4 hours. This process was repeated three times to obtain ammonium-form zeolite. Finally, it was calcined at 700℃ for 4 hours to obtain the hydrogen-form ZSM-5 / ZSM-12 / SAPO-11 composite molecular sieve.

[0169] The preparation of the ZSM-5 precrystallized solution includes the following steps: Sodium hydroxide is used as the sodium source, and sodium aluminate is used as the aluminum source, both dissolved in deionized water. Then, tetrapropylammonium hydroxide (TPAOH) as a template agent and tetraethyl orthosilicate as a silicon source are added dropwise to the solution. After stirring, a gel is formed, and the solution is precrystallized at 200°C for 6 hours in a hydrothermal reactor to obtain the ZSM-5 precrystallized solution. The molar ratio is controlled as Na₂O:Al₂O₃:SiO₂:TPAOH:H₂O = 50:0.8:140:60:3200.

[0170] The preparation of ZSM-12 precrystallized solution includes the following steps: Sodium hydroxide is used as the sodium source, and sodium aluminate is used as the aluminum source, both dissolved in deionized water. Then, tetraethylammonium hydroxide (TEAOH) as a template agent and tetraethyl orthosilicate as a silicon source are added dropwise to the solution. After stirring, a gel is formed, and the solution is precrystallized at 170°C for 30 hours in a hydrothermal reactor to obtain the ZSM-12 precrystallized solution. The molar ratio is controlled as Na₂O:Al₂O₃:SiO₂:TEAOH:H₂O = 12:1.6:85:23:2400.

[0171] SAPO-11 was prepared by the following steps: Aluminum sulfate was dissolved in deionized water as the aluminum source. Phosphoric acid (as the phosphorus source), di-n-propylamine (as the template agent), and tetraethyl orthosilicate (as the silicon source) were then added dropwise to the solution. After stirring, a gel was formed. The gel was crystallized at 190°C for 5 days in a hydrothermal reactor. The gel was then filtered, washed, dried, and calcined to obtain SAPO-11. The molar ratio was controlled as Al₂O₃:P₂O₅:di-n-propylamine:SiO₂:H₂O = 14:14:14:0.1:30.

[0172] The prepared hydrogen-form ZSM-5 / ZSM-12 / SAPO-11 composite molecular sieve was uniformly mixed with boehmite, guar gum powder, and citric acid, shaped, air-dried at room temperature, then dried at 120℃ for 2 hours, and calcined at 500℃ for 4 hours to obtain the catalyst. The catalyst was sieved to 20–40 mesh and loaded into the central isothermal zone of the reactor, with quartz wool packed both above and below it. The reaction was carried out at atmospheric pressure, and the catalyst was activated at 450℃ for 2 hours under nitrogen protection at a flow rate of 30 mL / min, after which the temperature was lowered to the reaction temperature.

[0173] The mass ratio of hydrogen-form ZSM-5 / ZSM-12 / SAPO-11 composite molecular sieve to pseudoboehmite is 1:1; the mass of guar gum powder accounts for 3% of the total mass of hydrogen-form ZSM-5 / ZSM-12 / SAPO-11 composite molecular sieve, pseudoboehmite, guar gum powder, and citric acid, and the mass of citric acid accounts for 2% of the total mass of hydrogen-form ZSM-5 / ZSM-12 / SAPO-11 composite molecular sieve, pseudoboehmite, guar gum powder, and citric acid.

[0174] 2-MN, methanol, and solvent in a molar ratio of 1:1:3 were uniformly mixed and pumped into the reactor using a constant flow pump at a space velocity of 1 h⁻¹. -1 The reaction temperature was 500℃, and the reaction time was 10 h. The reaction product was collected after condensation and subjected to gas phase analysis for its composition. The results are shown in the table below:

[0175] Table 11 Results of the molecular sieve catalytic reaction obtained in Example 11

[0176]

[0177] Example 12

[0178] This embodiment provides a method for preparing a hydrogen-form ZSM-5 / ZSM-12 / SAPO-11 composite molecular sieve for the alkylation reaction of naphthalene / 2-methylnaphthalene methanol, comprising the following steps:

[0179] By mass fraction, 35 parts of ZSM-5 pre-crystallized solution, 20 parts of ZSM-12 pre-crystallized solution, and 75 parts of SAPO-11 were mixed evenly at room temperature, and then co-crystallized in a hydrothermal reactor at 100℃ for 3 days. Insoluble crystals in the product were filtered out, washed with deionized water at 50℃, dried at 150℃ for 6 hours, and then calcined at 600℃ for 3 hours to obtain a ZSM-5 / ZSM-12 / SAPO-11 composite molecular sieve. The ZSM-5 / ZSM-12 / SAPO-11 composite molecular sieve was then soaked in a 1 mol / L ammonium nitrate aqueous solution at a solid-liquid ratio of 1:10 at 80℃ for 2 hours, and then dried at 120℃ for 4 hours. This process was repeated three times to obtain ammonium-form zeolite. Finally, it was calcined at 650℃ for 5 hours to obtain the hydrogen-form ZSM-5 / ZSM-12 / SAPO-11 composite molecular sieve.

[0180] The preparation of the ZSM-5 precrystallized solution includes the following steps: Sodium hydroxide is used as the sodium source, and sodium aluminate is used as the aluminum source, both dissolved in deionized water. Then, tetrapropylammonium hydroxide (TPAOH) as a template agent and tetraethyl orthosilicate as a silicon source are added dropwise to the solution. After stirring, a gel is formed, and the solution is precrystallized at 180°C for 15 hours in a hydrothermal reactor to obtain the ZSM-5 precrystallized solution. The molar ratio is controlled as Na₂O:Al₂O₃:SiO₂:TPAOH:H₂O = 45:1.6:150:50:3600.

[0181] The preparation of ZSM-12 precrystallized solution includes the following steps: Sodium hydroxide is used as the sodium source, and sodium aluminate is used as the aluminum source, both dissolved in deionized water. Then, tetraethylammonium hydroxide (TEAOH) as a template agent and tetraethyl orthosilicate as a silicon source are added dropwise to the solution. After stirring, a gel is formed, and the solution is precrystallized at 180℃ for 20 hours in a hydrothermal reactor to obtain the ZSM-12 precrystallized solution. The molar ratio is controlled as Na₂O:Al₂O₃:SiO₂:TEAOH:H₂O = 16:1.3:112:13:1500.

[0182] SAPO-11 was prepared by the following steps: aluminum sulfate was dissolved in deionized water as the aluminum source. Phosphoric acid (as the phosphorus source), di-n-propylamine (as the template agent), and tetraethyl orthosilicate (as the silicon source) were then added dropwise to the solution. After stirring, a gel was formed. The gel was crystallized in a hydrothermal reactor at 200°C for 4 days. After filtration, washing, drying, and calcination, SAPO-11 was obtained. The molar ratio was controlled as Al₂O₃:P₂O₅:di-n-propylamine:SiO₂:H₂O = 8:8:8:0.3:40.

[0183] The prepared hydrogen-form ZSM-5 / ZSM-12 / SAPO-11 composite molecular sieve was uniformly mixed with boehmite, guar gum powder, and citric acid, shaped, air-dried at room temperature, then dried at 120℃ for 2 hours, and calcined at 500℃ for 4 hours to obtain the catalyst. The catalyst was sieved to 20–40 mesh and loaded into the central isothermal zone of the reactor, with quartz wool packed both above and below it. The reaction was carried out at atmospheric pressure, and the catalyst was activated at 450℃ for 2 hours under nitrogen protection at a flow rate of 30 mL / min, after which the temperature was lowered to the reaction temperature.

[0184] The mass ratio of hydrogen-form ZSM-5 / ZSM-12 / SAPO-11 composite molecular sieve to pseudoboehmite is 1:1; the mass of guar gum powder accounts for 3% of the total mass of hydrogen-form ZSM-5 / ZSM-12 / SAPO-11 composite molecular sieve, pseudoboehmite, guar gum powder, and citric acid, and the mass of citric acid accounts for 2% of the total mass of hydrogen-form ZSM-5 / ZSM-12 / SAPO-11 composite molecular sieve, pseudoboehmite, guar gum powder, and citric acid.

[0185] 2-MN, methanol, and solvent were uniformly mixed in a molar ratio of 1:1:3 and then pumped into the reactor using a constant flow pump at a space velocity of 0.7 h⁻¹. -1 The reaction temperature was 400℃, and the reaction time was 10 h. The reaction product was collected after condensation and subjected to gas phase analysis for its composition. The results are shown in the table below:

[0186] Table 12 Results of molecular sieve catalytic reaction obtained in Example 12

[0187]

[0188] Example 13

[0189] This embodiment provides a method for preparing a hydrogen-form ZSM-5 / ZSM-12 / SAPO-11 composite molecular sieve for the alkylation reaction of naphthalene / 2-methylnaphthalene methanol, comprising the following steps:

[0190] By mass fraction, 40 parts of ZSM-5 pre-crystallized solution, 25 parts of ZSM-12 pre-crystallized solution, and 60 parts of SAPO-11 were mixed evenly at room temperature, and then co-crystallized in a hydrothermal reactor at 150℃ for 2 days. Insoluble crystals in the product were filtered out, washed with deionized water at 40℃, dried at 130℃ for 10 hours, and then calcined at 550℃ for 4 hours to obtain a ZSM-5 / ZSM-12 / SAPO-11 composite molecular sieve. The ZSM-5 / ZSM-12 / SAPO-11 composite molecular sieve was then soaked in a 1 mol / L ammonium nitrate aqueous solution at a solid-liquid ratio of 1:10 at 80℃ for 2 hours, and then dried at 120℃ for 4 hours. This process was repeated three times to obtain ammonium-form zeolite. Finally, it was calcined at 600℃ for 5 hours to obtain the hydrogen-form ZSM-5 / ZSM-12 / SAPO-11 composite molecular sieve.

[0191] The preparation of ZSM-5 precrystallized solution includes the following steps: Sodium hydroxide is used as the sodium source, and sodium aluminate is used as the aluminum source, both dissolved in deionized water. Then, tetrapropylammonium hydroxide (TPAOH) as a template agent and tetraethyl orthosilicate as a silicon source are added dropwise to the solution. After stirring, a gel is formed, and the solution is precrystallized at 190℃ for 10 hours in a hydrothermal reactor to obtain the ZSM-5 precrystallized solution. The molar ratio is controlled as Na₂O:Al₂O₃:SiO₂:TPAOH:H₂O = 43:1.2:160:58:2900.

[0192] The preparation of ZSM-12 precrystallized solution includes the following steps: Sodium hydroxide is used as the sodium source, and sodium aluminate is used as the aluminum source, both dissolved in deionized water. Then, tetraethylammonium hydroxide (TEAOH) as a template agent and tetraethyl orthosilicate as a silicon source are added dropwise to the solution. After stirring, a gel is formed, and the solution is precrystallized at 190°C for 6 hours in a hydrothermal reactor to obtain the ZSM-12 precrystallized solution. The molar ratio is controlled as Na₂O:Al₂O₃:SiO₂:TEAOH:H₂O = 8:0.8:130:18:1750.

[0193] SAPO-11 was prepared by the following steps: Aluminum sulfate was dissolved in deionized water as the aluminum source. Phosphoric acid (as the phosphorus source), di-n-propylamine (as the template agent), and tetraethyl orthosilicate (as the silicon source) were then added dropwise to the solution. After stirring, a gel was formed. The gel was crystallized in a hydrothermal reactor at 220°C for 3 days. The gel was then filtered, washed, dried, and calcined to obtain SAPO-11. The molar ratio was controlled as Al₂O₃:P₂O₅:di-n-propylamine:SiO₂:H₂O = 12:12:12:0.4:45.

[0194] The prepared hydrogen-form ZSM-5 / ZSM-12 / SAPO-11 composite molecular sieve was uniformly mixed with boehmite, guar gum powder, and citric acid, shaped, air-dried at room temperature, then dried at 120℃ for 2 hours, and calcined at 500℃ for 4 hours to obtain the catalyst. The catalyst was sieved to 20–40 mesh and loaded into the central isothermal zone of the reactor, with quartz wool packed both above and below it. The reaction was carried out at atmospheric pressure, and the catalyst was activated at 450℃ for 2 hours under nitrogen protection at a flow rate of 30 mL / min, after which the temperature was lowered to the reaction temperature.

[0195] The mass ratio of hydrogen-form ZSM-5 / ZSM-12 / SAPO-11 composite molecular sieve to pseudoboehmite is 1:1; the mass of guar gum powder accounts for 3% of the total mass of hydrogen-form ZSM-5 / ZSM-12 / SAPO-11 composite molecular sieve, pseudoboehmite, guar gum powder, and citric acid, and the mass of citric acid accounts for 2% of the total mass of hydrogen-form ZSM-5 / ZSM-12 / SAPO-11 composite molecular sieve, pseudoboehmite, guar gum powder, and citric acid.

[0196] 2-MN, methanol, and solvent were uniformly mixed in a molar ratio of 1:1:3 and then pumped into the reactor using a constant flow pump at a space velocity of 0.8 h⁻¹. -1 The reaction temperature was 420℃, and the reaction time was 10 h. The reaction product was collected after condensation and subjected to gas phase analysis for its composition. The results are shown in the table below:

[0197] Table 13 Results of molecular sieve catalytic reaction obtained in Example 13

[0198]

[0199]

[0200] Comparative Example 1

[0201] This comparative example provides a method for preparing a hydrogen-form ZSM-5 / ZSM-12 / SAPO-11 composite molecular sieve for the alkylation reaction of naphthalene / 2-methylnaphthalene with methanol, comprising the following steps:

[0202] Comparative Example 1 was identical to Example 1 except for the different mass fractions of ZSM-5, ZSM-12, and SAPO-11, with the mass fractions changed to 25 parts for ZSM-5, 15 parts for ZSM-12, and 60 parts for SAPO-11. The results are shown in the table below:

[0203] Table 14 Results of molecular sieve catalytic reactions obtained in Comparative Example 1

[0204]

[0205] Comparative Example 2

[0206] This comparative example provides a method for preparing a hydrogen-form ZSM-5 / ZSM-12 / SAPO-11 composite molecular sieve for the alkylation reaction of naphthalene / 2-methylnaphthalene with methanol, comprising the following steps:

[0207] Comparative Example 2 was identical to Example 1 except for the different mass fractions of ZSM-5, ZSM-12, and SAPO-11, with the mass fractions changed to 35 parts for ZSM-5, 25 parts for ZSM-12, and 40 parts for SAPO-11. The results are shown in the table below:

[0208] Table 15 Results of molecular sieve catalytic reactions obtained in Comparative Example 2

[0209]

[0210]

[0211] Comparative Example 3

[0212] This comparative example provides a method for preparing a hydrogen-form ZSM-5 / ZSM-12 / SAPO-11 composite molecular sieve for the alkylation reaction of naphthalene / 2-methylnaphthalene with methanol, comprising the following steps:

[0213] Comparative Example 3 was identical to Example 5 except for the molar ratios of Na₂O, Al₂O₃, SiO₂, TPAOH, and H₂O in ZSM-5. The molar ratios of Na₂O, Al₂O₃, SiO₂, TPAOH, and H₂O were changed to Na₂O:Al₂O₃:SiO₂:TPAOH:H₂O = 45:1.5:130:53:3000. The results are shown in the table below:

[0214] Table 16 Results of molecular sieve catalytic reactions obtained in Comparative Example 3

[0215]

[0216] Comparative Example 4

[0217] This comparative example provides a method for preparing a hydrogen-form ZSM-5 / ZSM-12 / SAPO-11 composite molecular sieve for the alkylation reaction of naphthalene / 2-methylnaphthalene with methanol, comprising the following steps:

[0218] Comparative Example 4 was identical to Example 6 except for the different molar ratios of Na₂O, Al₂O₃, SiO₂, TEAOH, and H₂O in ZSM-12. The molar ratio of Na₂O:Al₂O₃:SiO₂:TEAOH:H₂O was changed to Na₂O:Al₂O₃:SiO₂:TEAOH:H₂O = 10:1.5:80:20:2000. The results are shown in the table below:

[0219] Table 17 Results of molecular sieve catalytic reactions obtained in Comparative Example 4

[0220]

[0221]

[0222] Comparative Example 5

[0223] This comparative example provides a method for preparing a hydrogen-form ZSM-5 / ZSM-12 / SAPO-11 composite molecular sieve for the alkylation reaction of naphthalene / 2-methylnaphthalene with methanol, comprising the following steps:

[0224] Comparative Example 5 was identical to Example 9 except for the co-crystallization times of ZSM-5, ZSM-12, and SAPO-11, which were changed to 4 days. The results are shown in the table below:

[0225] Table 18 Results of molecular sieve catalytic reactions obtained in Comparative Example 5

[0226]

[0227] Comparative Example 6

[0228] This comparative example provides a method for preparing a hydrogen-form ZSM-5 / ZSM-12 / SAPO-11 composite molecular sieve for the alkylation reaction of naphthalene / 2-methylnaphthalene with methanol, comprising the following steps:

[0229] Comparative Example 6 was identical to Example 9 except for the co-crystallization times of ZSM-5, ZSM-12, and SAPO-11, which were changed to 2 days. The results are shown in the table below:

[0230] Table 19 Results of molecular sieve catalytic reactions obtained in Comparative Example 6

[0231]

[0232]

[0233] As can be seen from Examples 1-13 and Comparative Examples 1-6 above, the hydrogen-form ZSM-5 / ZSM-12 / SAPO-11 composite molecular sieve prepared by the present invention for the alkylation reaction of naphthalene / 2-methylnaphthalene methanol exhibits both high 2-MN conversion and high 2,6-DMN selectivity. The initial 2-MN conversion is 36.75%-38.58%, and the 2,6-DMN selectivity is 56.42%-58.84%. After 10 hours of reaction, the 2-MN... The conversion rate was 21.98%-23.96%, and the selectivity for 2,6-DMN was 49.06%-50.75%, exhibiting good anti-carbon deposition properties. Furthermore, the molar ratio of 2,6-DMN to 2,7-DMN in the product was greater than 1.4. Initially, the molar ratio of 2,6-DMN to 2,7-DMN was 1.73-1.80, and after 10 hours of reaction, the molar ratio of 2,6-DMN to 2,7-DMN was 1.64-1.70, which is beneficial for the subsequent separation of the two.

[0234] The composite molecular sieve prepared by the method of the present invention avoids the defects of a single molecular sieve, improves the catalytic activity of the molecular sieve, the selectivity of 2,6-DMN, the resistance to carbon deposition, and the molar ratio of 2,6-DMN to 2,7-DMN in the product. Its excellent synergistic effect has great application value in the catalytic methanol alkylation reaction of naphthalene / 2-methylnaphthalene to prepare 2,6-DMN.

[0235] The above description is only of the preferred embodiment of the present invention and should not be construed as limiting the scope of the claims. The present invention is not limited to the above embodiments, and variations in its specific structure are permitted. All variations made within the scope of the independent claims of the present invention are also within the scope of protection of the present invention.

[0236] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

Claims

1. The application of a hydrogen-form ZSM-5 / ZSM-12 / SAPO-11 composite molecular sieve in the preparation of 2,6-dimethylnaphthalene from methanol via alkylation of 2-methylnaphthalene, characterized in that, The preparation method of the hydrogen-form ZSM-5 / ZSM-12 / SAPO-11 composite molecular sieve includes the following steps: The ZSM-5 precrystallization solution, ZSM-12 precrystallization solution and SAPO-11 were mixed evenly and co-crystallized at 150-200℃ for 1-4 days, and then calcined once to obtain ZSM-5 / ZSM-12 / SAPO-11 composite molecular sieve. The ZSM-5 / ZSM-12 / SAPO-11 composite molecular sieve was soaked in ammonium nitrate solution and dried to obtain ammonium-type zeolite. The ammonium-type zeolite was then calcined a second time to obtain hydrogen-type ZSM-5 / ZSM-12 / SAPO-11 composite molecular sieve. ZSM-5 precrystallization solution is prepared by the following process: Sodium and aluminum sources were dissolved in deionized water, and then template agent and silicon source were added. After stirring, a gel was formed and pre-crystallized at 160-200℃ for 6-24 hours to obtain ZSM-5 pre-crystallized solution. ZSM-12 precrystallization solution is prepared by the following process: Sodium and aluminum sources were dissolved in deionized water, then template agent and silicon source were added, and a gel was formed after stirring. The gel was then pre-crystallized in a hydrothermal reactor at 150–190 °C for 6–48 h to obtain a ZSM-12 pre-crystallized solution.

2. The application according to claim 1, characterized in that, The mass ratio of ZSM-5 precrystallization solution, ZSM-12 precrystallization solution to SAPO-11 is 15-40:10-35:25-75; the first calcination temperature is 400-600℃ and the time is 3-6h; the second calcination temperature is 500-700℃ and the time is 4-6h.

3. The application according to claim 1, characterized in that, In preparing the ZSM-5 precrystallization solution, the sodium source used is sodium hydroxide, the aluminum source is sodium aluminate, the template agent is tetrapropylammonium hydroxide (TPAOH), and the silicon source is water glass or tetraethyl orthosilicate. The amounts of sodium source, aluminum source, silicon source, template agent and deionized water are determined according to the molar ratio of Na2O:Al2O3:SiO2:TPAOH:H2O = 40~50:0.5~1.6:130~160:45~60:2500~3600.

4. The application according to claim 1, characterized in that, In preparing the ZSM-12 precrystallization solution, the sodium source used is sodium hydroxide or sodium oxide, the aluminum source is sodium aluminate or aluminum sulfate, the template agent is tetraethylammonium hydroxide (TEAOH), and the silicon source is water glass or tetraethyl orthosilicate. The amounts of sodium source, aluminum source, silicon source, template agent, and deionized water are determined according to the molar ratio Na2O:Al2O3:SiO2:TEAOH:H2O = 5~16:0.5~1.6:80~130:13~28:1500~3200.

5. The application according to claim 1, characterized in that, SAPO-11 is produced through the following process: An aluminum source was dissolved in deionized water, and a phosphorus source, template agent, and silicon source were added. After stirring, a gel was formed and crystallized at 180-220℃ for 3-6 days. After filtration, washing, drying, and calcination, SAPO-11 was obtained.

6. The application according to claim 5, characterized in that, When preparing SAPO-11, the aluminum source is sodium aluminate or aluminum sulfate, the phosphorus source is phosphoric acid or ammonium hydrogen phosphate, the template agent is di-n-propylamine, and the silicon source is water glass or tetraethyl orthosilicate.

7. An application according to any one of claims 1-6, characterized in that, A hydrogen-form ZSM-5 / ZSM-12 / SAPO-11 composite molecular sieve was uniformly mixed with binder, extrusion aid, and adhesive solvent, then shaped, dried, and calcined to obtain a catalyst. This catalyst was added to a reactor and reacted under normal pressure. The catalyst was activated under nitrogen protection at a flow rate of 30 mL / min. Then, a mixture of 2-methylnaphthalene, methanol, and solvent in a molar ratio of 1:1:3 was pumped into the reactor at a space velocity of 0.25–1 h⁻¹. -1 The reaction temperature is 350-500℃ and the reaction time is 10h.

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