A modified usy molecular sieve, a preparation method thereof and a method for synthesizing 2,6-diisopropyl naphthalene

Abstract

This invention provides a modified USY molecular sieve, its preparation method, and a method for synthesizing 2,6-diisopropylnaphthalene. The preparation method includes sequentially mixing the USY molecular sieve with a solution containing ammonium ions, a solution containing rare earth metal ions, and a solution containing cobalt ions, and then carrying out an ion exchange reaction in the solution. The modified USY molecular sieve of this invention exhibits good stability and catalytic performance. When used to catalyze the synthesis of 2,6-diisopropylnaphthalene from propylene and naphthalene sources, it achieves high conversion rates of the naphthalene source and high selectivity for 2,6-diisopropylnaphthalene. Moreover, the catalyst is reusable, and the catalytic effect is reproducible, making it suitable for the industrial production of 2,6-diisopropylnaphthalene.

Description

Technical Field

[0001] This invention belongs to the field of fine chemical technology, specifically relating to a modified USY molecular sieve, its preparation method, and a method for synthesizing 2,6-diisopropylnaphthalene. Background Technology

[0002] Diisopropylnaphthalene (DIPN) is an important organic chemical raw material with advantages such as being colorless, odorless, having a high boiling point, low toxicity, low freezing point, and strong fuel solubility. 2,6-Diisopropylnaphthalene (2,6-DIPN) can be used to synthesize 2,6-naphthalenedicarboxylic acid, which is used in the production of polyethylene terephthalate (PEN) and thermally oriented liquid crystal polymers (LCPs), making it a high-value-added fine chemical product. PEN possesses unique heat resistance, mechanical properties, gas barrier properties, chemical stability, and radiation resistance, and is widely used in electronic devices, high-performance films, food packaging films, insulating materials, and aerospace. Currently, the bottleneck for the large-scale application of PEN lies in the complex and costly preparation process of its key raw material, 2,6-diisopropylnaphthalene.

[0003] my country has abundant naphthalene resources. Using inexpensive and plentiful naphthalene as a raw material, the synthesis of 2,6-diisopropylnaphthalene via alkylation can broaden the sources of raw materials for PEN synthesis, increase the added value of naphthalene and propylene, and shorten the process route. However, due to the numerous isomers of 2,6-diisopropylnaphthalene with similar boiling points, separation is extremely difficult. Therefore, improving the selectivity of 2,6-diisopropylnaphthalene is key to achieving the preparation of 2,6-diisopropylnaphthalene from naphthalene.

[0004] The synthesis of diisopropylnaphthalene generally employs a liquid-phase alkylation method with naphthalene and propylene / isopropanol. CN107954812A discloses a method for naphthalene alkylation in a fixed-bed reaction, using a silanized modified ZSM-5 / ZSM-12 composite molecular sieve as a catalyst, with a 2,6-DIPN selectivity of only 41%. CN 112661587 A discloses a method for preparing 2,6-dialkylnaphthalene. This method involves synthesizing 2,6-dialkylnaphthalene from naphthalene and an alkylating agent under alkylation reaction conditions and in the presence of a solid acid catalyst. The method provides a naphthalene conversion rate as high as 48%, a 2,6-dialkylnaphthalene selectivity as high as 61%, and a heavy component content (substances with a molecular weight ≥ trialkylnaphthalene) of less than 0.8 wt% in the product. After 24 hours of device operation, the naphthalene conversion rate reaches 49%, the 2,6-dialkylnaphthalene selectivity reaches 61%, and the heavy component content (substances with a molecular weight ≥ trialkylnaphthalene) in the product is less than 0.8 wt%. However, this method has a low naphthalene conversion rate and is cumbersome to prepare.

[0005] Based on this, current methods for synthesizing diisopropylnaphthalene generally suffer from problems such as low naphthalene conversion, low selectivity for 2,6-DIPN, and cumbersome catalyst preparation methods. Moreover, the isopropylation of naphthalene often employs batch reactor or fixed-bed reactor processes, during which the catalyst is very easy to deactivate, making it difficult to achieve continuous preparation of 2,6-DIPN.

[0006] Y-type molecular sieves are synthesized from HY molecular sieves through high-temperature hydrothermal dealumination. They possess regular, open three-dimensional channels, adjustable acid content, and good hydrothermal stability. USY is a modified Y-type molecular sieve, which increases the silicon-to-aluminum ratio in the molecular sieve framework by removing Al and replenishing Si, making the structure more stable. USY molecular sieves have wide industrial applications in catalytic cracking, olefin alkylation, alkyl transfer, and gas adsorption separation. With the trend towards low-lead or lead-free gasoline, ultra-stable USY molecular sieves have entered the catalytic cracking arena and have been rapidly promoted and applied. This is mainly because using this zeolite molecular sieve as a catalyst can reduce hydrogen transfer reactions, increase the olefin content and octane number in gasoline, reduce coke yield, and increase light oil yield and throughput. However, due to its still relatively low and difficult-to-control silicon-to-aluminum ratio, numerous lattice defects, and the fact that removed aluminum remains within the molecular sieve cage, the migration of aluminum from the sub-outer layer to the outer layer leads to uneven distribution of bulk aluminum and enrichment of amorphous aluminum surfaces, which in turn promotes coking and excessive cracking, affecting further improvement in selectivity. There are currently no reports on the use of USY molecular sieves in the catalytic synthesis of DIPN from naphthalene and propylene sources. Summary of the Invention

[0007] The purpose of this invention is to provide a modified USY molecular sieve, its preparation method, and a method for synthesizing 2,6-diisopropylnaphthalene. The modified USY molecular sieve of this invention exhibits good stability and catalytic performance. When used to catalyze the synthesis of 2,6-diisopropylnaphthalene from propylene and naphthalene sources, it achieves high conversion rates of the naphthalene source and high selectivity for 2,6-diisopropylnaphthalene. Furthermore, the catalyst is reusable, and the catalytic effect is reproducible, making it suitable for the industrial production of 2,6-diisopropylnaphthalene.

[0008] The objective of this invention is achieved through the following technical solution:

[0009] In a first aspect, the present invention provides a method for preparing modified USY molecular sieve, the method comprising mixing USY molecular sieve sequentially with a solution containing ammonium ions, a solution containing rare earth metal ions, and a solution containing cobalt ions, and carrying out an ion exchange reaction in the solution.

[0010] In some embodiments of the present invention, the ammonium ion-containing solution is obtained by dissolving an ammonium salt in water; preferably, the ammonium salt includes at least one of ammonium nitrate, ammonium chloride, and ammonium sulfate, and is preferably ammonium nitrate.

[0011] In some embodiments of the present invention, the solution containing rare earth metal ions is obtained by dissolving a water-soluble salt of a rare earth metal in water; preferably, the water-soluble salt of the rare earth metal includes at least one of praseodymium and / or samarium nitrate, sulfate, and hydrochloride.

[0012] In some embodiments of the present invention, the cobalt ion-containing solution is obtained by dissolving a cobalt salt in water; preferably, the cobalt salt includes at least one of cobalt nitrate, cobalt sulfate, and cobalt chloride.

[0013] In some embodiments of the present invention, the concentration of ammonium ions in the solution containing ammonium ions is 0.05 to 0.15 mol / L.

[0014] In some embodiments of the present invention, the concentration of ammonium ions in the solution containing ammonium ions is 0.05 to 0.15 mol / L, which means that the concentration of ammonium ions can be selected from any of the following concentrations or any value between any two of them: 0.05, 0.06, 0.07, 0.08, 0.09, 0.1, 0.11, 0.12, 0.13, 0.14, 0.15 mol / L.

[0015] In some embodiments of the present invention, the concentration of ammonium ions in a solution containing ammonium ions refers to the concentration of the total amount of ammonium ions that have been ionized or have not been ionized in the solution.

[0016] In some embodiments of the present invention, the solid-liquid ratio (g / mL) of the USY molecular sieve mixed with the ammonium ion-containing solution is 1:(8-20).

[0017] In some embodiments of the present invention, the temperature for the ion exchange reaction between the USY molecular sieve and the solution containing ammonium ions is 70–90°C, and the time is 4–18 h.

[0018] In some embodiments of the present invention, the preparation method further includes drying and calcining the USY molecular sieve after ion exchange with ammonium ions; preferably, the drying conditions include a temperature of 80-120°C and a time of 14-18h, and / or the calcination conditions include a temperature of 450-550°C and a time of 3-7h.

[0019] In some embodiments of the present invention, the USY molecular sieve is mixed with a solution containing ammonium ions 2 to 3 times consecutively and an ion exchange reaction is carried out in the solution, with each reaction lasting 2 to 6 hours. Preferably, after each reaction, the recovered solid is washed with water and dried at 80 to 120°C for 14 to 18 hours. When it is necessary to calcine the USY molecular sieve, only the USY molecular sieve after the last drying is calcined.

[0020] In some embodiments of the present invention, mixing the USY molecular sieve with a solution containing ammonium ions 2 to 3 times consecutively and carrying out an ion exchange reaction in the solution refers to mixing the USY molecular sieve with a solution containing ammonium ions that is different from the previous ion exchange reaction and carrying out an ion exchange reaction in the solution; thereby enabling the ammonium ions to be more uniformly loaded on the USY molecular sieve and obtaining a USY molecular sieve with a higher ammonium ion loading.

[0021] In some embodiments of the present invention, the concentration of rare earth metal ions in the solution containing rare earth metal ions is 0.1 to 1.5 mol / L, preferably 0.4 to 1.0 mol / L.

[0022] In some embodiments of the present invention, the concentration of rare earth metal ions in the solution containing rare earth metal ions is 0.1 to 1.5 mol / L, which means that the concentration of rare earth metal ions can be selected from any of the following concentrations or any value between any two of them: 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, 1.1, 1.2, 1.3, 1.4, 1.5 mol / L.

[0023] In some embodiments of the present invention, the concentration of rare earth metal ions in a solution containing rare earth metal ions refers to the total concentration of rare earth metal ions that have been ionized or have not been ionized in the solution.

[0024] In some embodiments of the present invention, the solid-liquid ratio (g / mL) of the USY molecular sieve mixed with the solution containing rare earth metal ions is 1:(5-30), preferably 1:(10-20).

[0025] In some embodiments of the present invention, the temperature for the ion exchange reaction between the USY molecular sieve and the solution containing rare earth metal ions is 70–90°C, and the time is 12–40 h.

[0026] In some embodiments of the present invention, the preparation method further includes drying and calcining the USY molecular sieve after ion exchange with rare earth metals; preferably, the drying conditions include a temperature of 100-140°C and a time of 14-18h, and / or the calcination conditions include a temperature of 500-600°C and a time of 2-6h.

[0027] In some embodiments of the present invention, the USY molecular sieve is mixed with a solution containing rare earth metal ions 2 to 4 times consecutively and an ion exchange reaction is carried out in the solution, with each reaction lasting 6 to 10 hours. Preferably, after each reaction, the recovered solid is washed with water and dried at 100 to 140°C for 14 to 18 hours. When it is necessary to calcine the USY molecular sieve, only the USY molecular sieve after the last drying is calcined.

[0028] In some embodiments of the present invention, mixing the USY molecular sieve with a solution containing rare earth metal ions 2 to 3 times consecutively and carrying out an ion exchange reaction in the solution refers to mixing the USY molecular sieve with a solution containing rare earth metal ions that is different from the previous ion exchange reaction and carrying out an ion exchange reaction in the solution; thereby enabling the rare earth metal ions to be more uniformly loaded on the USY molecular sieve and obtaining a USY molecular sieve with a higher rare earth metal ion loading.

[0029] In some embodiments of the present invention, the concentration of cobalt ions in the cobalt ion-containing solution is 0.05 to 2 mol / L, preferably 0.1 to 1.0 mol / L.

[0030] In some embodiments of the present invention, the concentration of cobalt ions in the cobalt ion-containing solution is 0.05 to 2 mol / L, meaning that the concentration of cobalt ions can be selected from any of the following concentrations or any value between any two of them: 0.05, 0.06, 0.07, 0.08, 0.09, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2 mol / L.

[0031] In some embodiments of the present invention, the concentration of cobalt ions in a solution containing cobalt ions refers to the concentration of the total amount of cobalt ions that have been ionized or have not been ionized in the solution.

[0032] In some embodiments of the present invention, the solid-liquid ratio (g / mL) of the USY molecular sieve mixed with the cobalt ion-containing solution is 1:(5-50), preferably 1:(10-30).

[0033] In some embodiments of the present invention, the temperature for the ion exchange reaction between the USY molecular sieve and the solution containing cobalt ions is 70–90°C, and the time is 4–8 h.

[0034] In some embodiments of the present invention, the preparation method includes drying and calcining the USY molecular sieve after ion exchange with cobalt ions; preferably, the drying conditions include a temperature of 100-140°C and a time of 14-18 h, and / or the calcination conditions include a temperature of 500-600°C and a time of 2-6 h.

[0035] In some embodiments of the present invention, the silicon-to-aluminum ratio of the USY molecular sieve is (5-200):1, preferably (5-100):1.

[0036] In some embodiments of the present invention, the preparation method further includes controlling the mass percentage of the rare earth metal in the modified USY molecular sieve to be 0.2wt% to 8wt% based on the total mass of the modified USY molecular sieve, preferably 1wt% to 5wt%.

[0037] In some embodiments of the present invention, the mass percentage of the rare earth metal in the modified USY molecular sieve, calculated based on the total mass of the modified USY molecular sieve, is 0.2 wt% to 8 wt%, meaning that the mass percentage can be selected from any of the following mass percentages or any value between any two of them: 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1, 2, 3, 4, 5, 6, 7, 8 wt%.

[0038] In some embodiments of the present invention, the preparation method further includes controlling the mass percentage of cobalt in the modified USY molecular sieve to be 0.2wt% to 8wt% based on the total mass of the modified USY molecular sieve, preferably 0.5wt% to 3wt%.

[0039] In some embodiments of the present invention, the mass percentage of cobalt in the modified USY molecular sieve, calculated based on the total mass of the modified USY molecular sieve, is 0.2 wt% to 8 wt%, meaning that the mass percentage can be selected from any of the following mass percentages or any value between any two of them: 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1, 2, 3, 4, 5, 6, 7, 8 wt%.

[0040] In some embodiments of the present invention, the preparation method further includes controlling the mass ratio of the rare earth metal in the modified USY molecular sieve to the mass ratio of the cobalt in the modified USY molecular sieve to be (0.5-4):1; preferably (1-3):1.

[0041] In some embodiments of the present invention, the ratio of the mass percentage of the rare earth metal in the modified USY molecular sieve to the mass percentage of the cobalt in the modified USY molecular sieve is (0.5 to 4):1, meaning that the mass percentage ratio can be selected from any of the following ratios or any ratio between any two of them: 0.5:1, 0.6:1, 0.7:1, 0.8:1, 0.9:1, 1:1, 1.5:1, 2:1, 2.5:1, 3:1, 3.5:1, 4:1.

[0042] In some embodiments of the present invention, the preparation method includes the following steps:

[0043] 1) Dissolve the ammonium salt in water to prepare a solution containing ammonium ions; preferably, the concentration of ammonium ions in the solution is 0.05–0.15 mol / L;

[0044] 2) The USY molecular sieve is mixed with the ammonium ion-containing solution obtained in step 1) at a solid-liquid ratio (g / mL) of 1:(8-20) and an ion exchange reaction is carried out in the solution at 70-90°C for 4-18 hours; preferably, after the reaction, the solid is recovered, washed with water, and dried at 80-120°C for 14-18 hours, followed by calcination at 450-550°C for 3-7 hours; more preferably, the ion exchange reaction is carried out in 2-3 times, that is, the steps of mixing, ion exchange reaction and drying are repeated 2-3 times before calcination, each time the ion exchange reaction is carried out for 2-6 hours, and the dried solid is calcined after the last drying.

[0045] 3) Dissolve water-soluble salts of rare earth metals in water to prepare a solution containing rare earth metal ions; preferably, the concentration of rare earth metal ions in the solution is 0.1–1.5 mol / L;

[0046] 4) The molecular sieve obtained in step 2) is mixed with the solution obtained in step 3) at a solid-liquid ratio (g / mL) of 1:(5-30) and subjected to an ion exchange reaction in the solution at 70-90°C for 12-40 h; preferably, after the reaction is completed, the solid is recovered, washed with water, and dried at 100-140°C for 14-18 h, and then calcined at 500-600°C for 2-6 h; more preferably, the ion exchange reaction is carried out in 2-4 times, that is, the steps of mixing, ion exchange reaction and drying are repeated 2-4 times before calcination, each time the ion exchange reaction is carried out for 6-10 h, and the dried solid is calcined after the last drying.

[0047] 5) Dissolve the water-soluble salt of cobalt in water to prepare a solution containing cobalt ions; preferably, the concentration of cobalt ions in the solution is 0.05–2 mol / L;

[0048] 6) The molecular sieve obtained in step 4) is mixed with the solution obtained in step 5) at a solid-liquid ratio (g / mL) of 1:(5-50) and subjected to an ion exchange reaction in the solution at 70-90°C for 4-8 hours; preferably, after the reaction is completed, the solid is recovered, washed with water and dried at 100-140°C for 14-18 hours, and then calcined at 500-600°C for 2-6 hours.

[0049] In some embodiments of the present invention, the water-soluble salt of the rare earth metal in step 3) is selected from at least one of the nitrate, sulfate, and chloride salts of at least one element selected from praseodymium and samarium.

[0050] Secondly, the present invention provides a modified USY molecular sieve prepared by the preparation method described in the first aspect.

[0051] In some embodiments of the present invention, the mass percentage of rare earth metals in the modified USY molecular sieve is 0.2wt% to 8wt%, preferably 1wt% to 5wt%.

[0052] In some embodiments of the present invention, the mass percentage of cobalt in the modified USY molecular sieve is 0.2wt% to 8wt%, preferably 0.5wt% to 3wt%.

[0053] In some embodiments of the present invention, the mass ratio of rare earth metal to cobalt in the modified USY molecular sieve is (0.5-4):1; preferably (1-3):1.

[0054] Thirdly, the present invention provides the application of the modified USY molecular sieve described in the second aspect in catalytic alkylation reactions, especially in the catalytic synthesis of 2,6-diisopropylnaphthalene.

[0055] Fourthly, the present invention provides a method for synthesizing 2,6-diisopropylnaphthalene, the method comprising using propylene and naphthalene source as raw materials and synthesizing 2,6-diisopropylnaphthalene using the modified USY molecular sieve catalyst described in the second aspect.

[0056] In some embodiments of the present invention, the naphthalene source is naphthalene and / or 2-isopropylnaphthalene.

[0057] In some embodiments of the present invention, the molar mass ratio of the naphthalene source to propylene is 1:(1-5), preferably 1:(1-2.2).

[0058] In some embodiments of the present invention, the molar mass ratio of naphthalene source to propylene is 1:(1-5), which means that the molar ratio of naphthalene source to propylene can be selected from any of the following molar ratios or any value between any two of them: 1:1, 1:1.5, 1:2, 1:2.5, 1:3, 1:3.5, 1:4, 1:4.5, 1:5.

[0059] In some embodiments of the present invention, the amount of the modified USY molecular sieve used in the synthesis reaction is 0.2% to 15% of the naphthalene source mass, preferably 0.5% to 10%.

[0060] In some embodiments of the present invention, the amount of modified USY molecular sieve used is 0.2% to 15% of the naphthalene source mass, which means that the percentage of the mass ratio of the modified USY molecular sieve to the naphthalene source can be selected from any of the following percentages or any value between any two of them: 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15%.

[0061] In some embodiments of the present invention, the temperature of the synthesis reaction is 150–300°C, preferably 170–250°C.

[0062] In some embodiments of the present invention, the pressure of the synthesis reaction is 0.5 to 6.0 MPa, preferably 1 to 4.0 MPa.

[0063] In some embodiments of the present invention, the reaction time of the raw materials in the reactor during the synthesis reaction is 1 to 10 hours, preferably 2 to 8 hours.

[0064] In some embodiments of the present invention, the reactor is any one of a batch reactor, a fixed bed reactor, a slurry bed reactor, a microchannel reactor, etc.

[0065] In some embodiments of the present invention, when using reactors such as batch reactors, fixed-bed reactors, and slurry-bed reactors for discontinuous production, the method for synthesizing 2,6-diisopropylnaphthalene includes the following steps:

[0066] (1) The naphthalene source and the modified USY molecular sieve described in the second aspect are loaded into the reactor at a dosage of 0.2% to 15% of the mass of the naphthalene source;

[0067] (2) Heat the reactor until the temperature reaches 150°C. Then, introduce gaseous or liquid propylene into the reactor at a molar mass ratio of naphthalene source to propylene of 1:(1~5). Keep the reactor temperature at 150~300°C and the pressure at 0.5~6.0 MPa, so that the raw materials react in the reactor for 1~10 hours.

[0068] In some embodiments of the present invention, when continuous production is carried out using a reactor such as a microchannel reactor, the method for synthesizing 2,6-diisopropylnaphthalene includes the following steps:

[0069] (a) The modified USY molecular sieve is mixed with the naphthalene source and the modified USY molecular sieve described in the second aspect at a mass ratio of 0.2% to 15% of the naphthalene source mass and heated to form a fluid. Then, the fluid containing the modified USY molecular sieve and the naphthalene source and liquid propylene are simultaneously introduced into the reactor at a molar mass ratio of naphthalene source to propylene of 1:(1 to 5).

[0070] (b) The temperature inside the reactor is controlled at 150–300 °C and the pressure at 0.5–6.0 MPa, so that the residence time of the fluid containing modified USY molecular sieve and naphthalene source and liquid propylene in the reactor is 1–10 h.

[0071] In some embodiments of the present invention, the temperature of the fluid in step (a) is 70–110°C.

[0072] In some embodiments of the present invention, the rate at which the fluid is introduced into the reactor in step (a) is 5 to 12 mL / min, measured by the volumetric flow rate of the naphthalene source.

[0073] In some embodiments of the present invention, step (a) further includes premixing the fluid containing the modified USY molecular sieve and naphthalene source and the liquid propylene in a premixer before introducing them into the reactor, and then introducing the premix of the fluid containing the modified USY molecular sieve and naphthalene source and the liquid propylene into the reactor from the premixer.

[0074] Fifthly, the present invention provides the application of the method described in the fourth aspect in the industrial production of 2,6-diisopropylnaphthalene, and the 2,6-diisopropylnaphthalene produced by applying the method described in the fourth aspect in the industrial production of 2,6-diisopropylnaphthalene.

[0075] The beneficial effects of this invention are as follows:

[0076] This invention proposes a novel method for preparing modified USY molecular sieves. The method involves sequentially mixing USY molecular sieves with solutions containing ammonium ions, rare earth metal ions, and cobalt ions, and then conducting an ion exchange reaction in the solution. This method modifies the USY molecular sieve without damaging its framework structure and effectively reduces catalyst carbon deposition. Furthermore, when the rare earth metal ions are praseodymium and / or samarium, they can passivate the acidic sites on the outer surface of the USY molecular sieve, thereby improving the conversion rate of the naphthalene source and the selectivity for 2,6-diisopropylnaphthalene. The modified USY molecular sieve of this invention exhibits high activity, good stability, and a long service life, allowing for long-term reuse. It shows promising application prospects in catalytic alkylation reactions, particularly in the catalytic synthesis of 2,6-diisopropylnaphthalene.

[0077] The present invention also proposes a method for synthesizing 2,6-diisopropylnaphthalene from propylene and naphthalene source using the modified USY molecular sieve of the present invention. This method can achieve a high conversion rate of naphthalene source and selectivity for 2,6-diisopropylnaphthalene. Moreover, the catalyst can be reused and the catalytic effect has good reproducibility, making it suitable for the industrial production of 2,6-diisopropylnaphthalene. Detailed Implementation

[0078] The following embodiments further illustrate the technology of the present invention. It should be noted that the specific embodiments below are only for explaining the present invention and do not constitute any limitation on the present invention. The present invention has been described with reference to typical embodiments, but it should be understood that the terms used herein are descriptive and explanatory, not limiting. Modifications can be made to the present invention within the scope of the claims, and revisions can be made to the present invention without departing from the scope and spirit of the present invention. Although the present invention described herein relates to specific methods, materials, and embodiments, it does not mean that the present invention is limited to the specific examples disclosed herein; on the contrary, the present invention can be extended to all other methods and applications having the same function.

[0079] The endpoints and any values ​​of the ranges disclosed in this invention 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 in this invention.

[0080] The raw materials and detection methods used in the preparation examples, comparative preparation examples, synthesis examples, and synthesis comparative examples of this invention are as follows:

[0081] Qualitative and quantitative analysis of the products was performed offline using a Shimadzu GC-2030 gas chromatograph, with separation using an HP-INNOWAX column and detection using a flame ionization detector.

[0082] Conversion rate of naphthalene = (number of moles of naphthalene converted / total number of moles of naphthalene) * 100%;

[0083] DIPN selectivity = (number of moles of DIPN in the product / total number of moles of the product) * 100%;

[0084] 2,6-DIPN selectivity = (number of moles of 2,6-DIPN in the product / total number of moles of disubstituted products) * 100%.

[0085] The modified molecular sieves used in the synthesis examples and comparative examples of this invention were prepared by the following preparation examples and comparative preparation examples.

[0086] Preparation Example 1

[0087] The preparation method of PrCo / USY molecular sieve includes the following steps:

[0088] 1) Dissolve ammonium nitrate in water to prepare an ammonium nitrate aqueous solution with an ammonium ion concentration of 0.1 mol / L (i.e., an ammonium nitrate concentration of 0.1 mol / L).

[0089] 2) The USY molecular sieve (silicon-to-aluminum ratio of 20:1) and the ammonium nitrate aqueous solution from step 1) were mixed at a solid-liquid ratio (g / mL) of 1:10 and stirred at 80°C for 4 hours. The solid was then recovered by filtration and washed three times with deionized water, and then dried at 100°C for 16 hours. The USY molecular sieve was then mixed again with a 0.1 mol / L ammonium nitrate aqueous solution at a solid-liquid ratio (g / mL) of 1:10 and stirred at 80°C for 4 hours. The solid was then recovered by filtration and washed three times with deionized water, and then dried at 100°C for 16 hours. Finally, the dried solid obtained after two ion exchanges with ammonium ions was calcined at 500°C for 5 hours to obtain the hydrogen form of the USY molecular sieve.

[0090] 3) Dissolve praseodymium nitrate in water to prepare an aqueous solution of praseodymium nitrate with a praseodymium ion concentration of 0.5 mol / L (i.e., a praseodymium nitrate concentration of 0.5 mol / L).

[0091] 4) The hydrogen-form USY molecular sieve obtained in step 2) was mixed with the praseodymium nitrate aqueous solution from step 3) at a solid-liquid ratio (g / mL) of 1:20 and stirred at 80°C for 8 hours. The solid was then recovered by filtration and washed three times with deionized water, followed by drying at 120°C for 16 hours. The USY molecular sieve was then mixed again with the praseodymium nitrate aqueous solution from step 3) at a solid-liquid ratio (g / mL) of 1:20 and stirred at 80°C for 8 hours. The solid was then recovered by filtration and washed three times with deionized water. The solid was washed three times with deionized water and then dried at 120°C for 16 hours. Subsequently, the USY molecular sieve was mixed with the praseodymium nitrate aqueous solution from step 3) at a solid-liquid ratio (g / mL) of 1:20 and stirred at 80°C for 8 hours. The solid was then recovered by filtration and washed three times with deionized water, and then dried at 120°C for 16 hours. Finally, the dried solid obtained after three praseodymium ion exchange processes was calcined at 550°C for 4 hours to obtain the praseodymium-modified USY molecular sieve.

[0092] 5) Dissolve cobalt nitrate in water to prepare a cobalt nitrate aqueous solution with a cobalt ion concentration of 0.3 mol / L (i.e., a cobalt nitrate concentration of 0.3 mol / L).

[0093] 6) The praseodymium-modified USY molecular sieve obtained in step 4) was mixed with the cobalt nitrate aqueous solution in step 5) at a solid-liquid ratio (g / mL) of 1:20 and stirred at 80°C for 6 hours. The solid was then recovered by filtration and washed three times with deionized water. The solid was then dried at 120°C for 16 hours. Finally, it was calcined at 550°C for 4 hours to obtain the modified USY molecular sieve, labeled as PrCo / USY molecular sieve.

[0094] According to the test results, based on the total mass of the PrCo / USY molecular sieve, the mass percentage of praseodymium in the PrCo / USY molecular sieve is 3 wt%, and the mass percentage of cobalt is 1 wt%.

[0095] Preparation Example 2

[0096] The preparation method of SmCo / USY molecular sieve includes the following steps:

[0097] 1) Dissolve ammonium nitrate in water to prepare an ammonium nitrate aqueous solution with an ammonium ion concentration of 0.1 mol / L (i.e., an ammonium nitrate concentration of 0.1 mol / L).

[0098] 2) The USY molecular sieve (silicon-to-aluminum ratio of 30:1) and the ammonium nitrate aqueous solution from step 1) were mixed at a solid-liquid ratio (g / mL) of 1:15 and stirred at 80°C for 4 hours. The solid was then recovered by filtration and washed three times with deionized water. The solid was then dried at 100°C for 16 hours. The USY molecular sieve and the ammonium nitrate aqueous solution from step 1) were mixed again at a solid-liquid ratio (g / mL) of 1:15 and stirred at 80°C for 4 hours. The solid was then recovered by filtration and washed three times with deionized water. The solid was then dried at 100°C for 16 hours. Finally, the dried solid obtained after two ion exchanges with ammonium ions was calcined at 500°C for 5 hours to obtain the hydrogen form of the USY molecular sieve.

[0099] 3) Dissolve samarium nitrate in water to prepare a samarium nitrate aqueous solution with a samarium ion concentration of 0.3 mol / L (i.e., a samarium nitrate concentration of 0.3 mol / L).

[0100] 4) The hydrogen-form USY molecular sieve obtained in step 2) was mixed with the samarium nitrate aqueous solution from step 3) at a solid-liquid ratio (g / mL) of 1:15 and stirred at 85°C for 8 hours. The solid was then recovered by filtration and washed three times with deionized water, followed by drying at 120°C for 16 hours. The USY molecular sieve was then mixed again with the samarium nitrate aqueous solution from step 3) at a solid-liquid ratio (g / mL) of 1:15 and stirred at 85°C for 8 hours. The solid was then recovered by filtration and washed three times with deionized water. The solid was washed three times with deionized water and then dried at 120°C for 16 hours. Subsequently, the USY molecular sieve was mixed with the samarium nitrate aqueous solution from step 3) at a solid-liquid ratio (g / mL) of 1:15 and stirred at 85°C for 8 hours. The solid was then recovered by filtration and washed three times with deionized water, and then dried at 120°C for 16 hours. Finally, the dried solid obtained after three ion exchanges with samarium ions was calcined at 550°C for 4 hours to obtain the samarium-modified USY molecular sieve.

[0101] 5) Dissolve cobalt nitrate in water to prepare a cobalt nitrate aqueous solution with a cobalt ion concentration of 0.3 mol / L (i.e., a cobalt nitrate concentration of 0.3 mol / L).

[0102] 6) The samarium-modified USY molecular sieve obtained in step 4) was mixed with the cobalt nitrate aqueous solution in step 5) at a solid-liquid ratio (g / mL) of 1:15 and stirred at 80°C for 6 hours. The solid was then recovered by filtration and washed three times with deionized water. The solid was then dried at 120°C for 16 hours. Finally, it was calcined at 550°C for 4 hours to obtain the modified USY molecular sieve, labeled as SmCo / USY molecular sieve.

[0103] According to the test results, based on the total mass of the SmCo / USY molecular sieve, the mass percentage of samarium in the SmCo / USY molecular sieve is 1 wt%, and the mass percentage of cobalt is 1 wt%.

[0104] Preparation Example 3

[0105] The preparation method of PrSmCo / USY molecular sieve includes the following steps:

[0106] 1) Dissolve ammonium nitrate in water to prepare an ammonium nitrate aqueous solution with an ammonium ion concentration of 0.1 mol / L (i.e., an ammonium nitrate concentration of 0.1 mol / L).

[0107] 2) The USY molecular sieve (silicon-to-aluminum ratio of 20:1) and the ammonium nitrate aqueous solution from step 1) were mixed at a solid-liquid ratio (g / mL) of 1:10 and stirred at 80°C for 4 hours. The solid was then recovered by filtration and washed three times with deionized water. The solid was then dried at 100°C for 16 hours. The USY molecular sieve and the ammonium nitrate aqueous solution from step 1) were mixed again at a solid-liquid ratio (g / mL) of 1:10 and stirred at 80°C for 4 hours. The solid was then recovered by filtration and washed three times with deionized water. The solid was then dried at 100°C for 16 hours. Finally, the dried solid obtained after two ion exchanges with ammonium ions was calcined at 500°C for 5 hours to obtain the hydrogen form of the USY molecular sieve.

[0108] 3) Dissolve praseodymium nitrate and samarium nitrate in water to prepare an aqueous solution with a praseodymium ion concentration of 0.25 mol / L (i.e., the concentration of praseodymium nitrate is 0.25 mol / L) and a samarium ion concentration of 0.15 mol / L (i.e., the concentration of samarium nitrate is 0.15 mol / L).

[0109] 4) The hydrogen-form USY molecular sieve obtained in step 2) is mixed with the aqueous solution in step 3) at a solid-liquid ratio (g / mL) of 1:15 and stirred at 80°C for 8 hours. The solid is then recovered by filtration and washed three times with deionized water. The solid is then dried at 120°C for 16 hours. The USY molecular sieve is again mixed with the aqueous solution in step 3) at a solid-liquid ratio (g / mL) of 1:15 and stirred at 80°C for 8 hours. The solid is then recovered by filtration and washed three times with deionized water. The solid was washed three times and then dried at 120°C for 16 hours. Subsequently, the USY molecular sieve was mixed with the aqueous solution from step 3) at a solid-liquid ratio (g / mL) of 1:15 and stirred at 80°C for 8 hours. The solid was then recovered by filtration and washed three times with deionized water, and then dried at 120°C for 16 hours. Finally, the dried solid obtained after three ion exchanges with praseodymium and samarium ions was calcined at 550°C for 4 hours to obtain praseodymium and samarium modified USY molecular sieve.

[0110] 5) Dissolve cobalt nitrate in water to prepare a cobalt nitrate aqueous solution with a cobalt ion concentration of 0.3 mol / L (i.e., a cobalt nitrate concentration of 0.3 mol / L).

[0111] 6) The praseodymium-modified USY molecular sieve obtained in step 4) was mixed with the cobalt nitrate aqueous solution in step 5) at a solid-liquid ratio (g / mL) of 1:15 and stirred at 80°C for 6 hours. The solid was then recovered by filtration and washed three times with deionized water. The solid was then dried at 120°C for 16 hours. Finally, it was calcined at 550°C for 4 hours to obtain the modified USY molecular sieve, labeled as PrSmCo / USY molecular sieve.

[0112] According to the test results, based on the total mass of the PrSmCo / USY molecular sieve, the mass percentage of praseodymium in the PrSmCo / USY molecular sieve is 1.5 wt%, the mass percentage of samarium is 0.5 wt%, and the mass percentage of cobalt is 1 wt%.

[0113] Preparation Example 4

[0114] The preparation method of PrCo / USY molecular sieve includes the following steps:

[0115] 1) Dissolve ammonium nitrate in water to prepare an ammonium nitrate aqueous solution with an ammonium ion concentration of 0.1 mol / L (i.e., an ammonium nitrate concentration of 0.1 mol / L).

[0116] 2) The USY molecular sieve (silicon-to-aluminum ratio of 20:1) and the ammonium nitrate aqueous solution from step 1) were mixed at a solid-liquid ratio (g / mL) of 1:10 and stirred at 80°C for 4 hours. The solid was then recovered by filtration and washed three times with deionized water, and then dried at 100°C for 16 hours. The USY molecular sieve was then mixed again with a 0.1 mol / L ammonium nitrate aqueous solution at a solid-liquid ratio (g / mL) of 1:10 and stirred at 80°C for 4 hours. The solid was then recovered by filtration and washed three times with deionized water, and then dried at 100°C for 16 hours. Finally, the dried solid obtained after two ion exchanges with ammonium ions was calcined at 500°C for 5 hours to obtain the hydrogen form of the USY molecular sieve.

[0117] 3) Dissolve praseodymium nitrate in water to prepare an aqueous solution of praseodymium nitrate with a praseodymium ion concentration of 0.5 mol / L (i.e., a praseodymium nitrate concentration of 0.5 mol / L).

[0118] 4) The hydrogen-form USY molecular sieve obtained in step 2) was mixed with the praseodymium nitrate aqueous solution in step 3) at a solid-liquid ratio (g / mL) of 1:15 and stirred at 80°C for 24 h. The solid was then recovered by filtration and washed three times with deionized water. The solid was then dried at 120°C for 16 h. The dried solid was then calcined at 550°C for 4 h to obtain the praseodymium-modified USY molecular sieve.

[0119] 5) Dissolve cobalt nitrate in water to prepare a cobalt nitrate aqueous solution with a cobalt ion concentration of 0.3 mol / L (i.e., a cobalt nitrate concentration of 0.3 mol / L).

[0120] 6) The praseodymium-modified USY molecular sieve obtained in step 4) is mixed with the cobalt nitrate aqueous solution in step 5) at a solid-liquid ratio (g / mL) of 1:15 and stirred at 80°C for 6 hours. The solid is then recovered by filtration and washed three times with deionized water. The solid is then dried at 120°C for 16 hours. Finally, it is calcined at 550°C for 4 hours to obtain the modified USY molecular sieve.

[0121] According to the test, based on the total mass of the modified USY molecular sieve, the mass percentage of praseodymium in the modified USY molecular sieve is 2.5 wt%, and the mass percentage of cobalt is 1 wt%.

[0122] Preparation Example 5

[0123] The preparation method of modified USY molecular sieve includes the following steps:

[0124] 1) Dissolve ammonium nitrate in water to prepare an ammonium nitrate aqueous solution with an ammonium ion concentration of 0.1 mol / L (i.e., an ammonium nitrate concentration of 0.1 mol / L).

[0125] 2) The USY molecular sieve (silicon-to-aluminum ratio of 20:1) and the ammonium nitrate aqueous solution from step 1) were mixed at a solid-liquid ratio (g / mL) of 1:10 and stirred at 80°C for 4 hours. The solid was then recovered by filtration and washed three times with deionized water, and then dried at 100°C for 16 hours. The USY molecular sieve was then mixed again with a 0.1 mol / L ammonium nitrate aqueous solution at a solid-liquid ratio (g / mL) of 1:10 and stirred at 80°C for 4 hours. The solid was then recovered by filtration and washed three times with deionized water, and then dried at 100°C for 16 hours. Finally, the dried solid obtained after two ion exchanges with ammonium ions was calcined at 500°C for 5 hours to obtain the hydrogen form of the USY molecular sieve.

[0126] 3) Dissolve praseodymium nitrate in water to prepare an aqueous solution of praseodymium nitrate with a praseodymium ion concentration of 3 mol / L (i.e., a praseodymium nitrate concentration of 3 mol / L).

[0127] 4) The hydrogen-form USY molecular sieve obtained in step 2) was mixed with the praseodymium nitrate aqueous solution from step 3) at a solid-liquid ratio (g / mL) of 1:15 and stirred at 80°C for 8 hours. The solid was then recovered by filtration and washed three times with deionized water, followed by drying at 120°C for 16 hours. The USY molecular sieve was then mixed again with the praseodymium nitrate aqueous solution from step 3) at a solid-liquid ratio (g / mL) of 1:15 and stirred at 80°C for 8 hours. The solid was then recovered by filtration and washed three times with deionized water. The solid was washed three times with deionized water and then dried at 120°C for 16 hours. Subsequently, the USY molecular sieve was mixed with the praseodymium nitrate aqueous solution from step 3) at a solid-liquid ratio (g / mL) of 1:15 and stirred at 80°C for 8 hours. The solid was then recovered by filtration and washed three times with deionized water, and then dried at 120°C for 16 hours. Finally, the dried solid obtained after three praseodymium ion exchange processes was calcined at 550°C for 4 hours to obtain the praseodymium-modified USY molecular sieve.

[0128] 5) Dissolve cobalt nitrate in water to prepare a cobalt nitrate aqueous solution with a cobalt ion concentration of 0.3 mol / L (i.e., a cobalt nitrate concentration of 0.3 mol / L).

[0129] 6) The praseodymium-modified USY molecular sieve obtained in step 4) is mixed with the cobalt nitrate aqueous solution in step 5) at a solid-liquid ratio (g / mL) of 1:15 and stirred at 80°C for 6 hours. The solid is then recovered by filtration and washed three times with deionized water. The solid is then dried at 120°C for 16 hours. Finally, it is calcined at 550°C for 4 hours to obtain the modified USY molecular sieve.

[0130] According to the test, based on the total mass of the modified USY molecular sieve, the mass percentage of praseodymium in the modified USY molecular sieve is 9 wt%, and the mass percentage of cobalt is 1 wt%.

[0131] Comparative Preparation Example 1

[0132] USY molecular sieve (silicon-to-aluminum ratio of 20:1) was directly calcined at 550℃ for 5 hours and used as a catalyst, labeled as USY molecular sieve.

[0133] Comparative Preparation Example 2

[0134] Similar to Preparation Example 1, except that only steps 1) and 2) are performed, the final result is a hydrogen-form USY molecular sieve, labeled as hydrogen-form USY molecular sieve.

[0135] Comparative preparation example 3

[0136] Similar to Preparation Example 1, except that steps 5) and 6) are omitted, the final result is praseodymium-modified USY molecular sieve, labeled as Pr / USY molecular sieve.

[0137] Comparative preparation example 4

[0138] 1) Dissolve ammonium nitrate in water to prepare an ammonium nitrate aqueous solution with an ammonium ion concentration of 0.1 mol / L (i.e., an ammonium nitrate concentration of 0.1 mol / L).

[0139] 2) The USY molecular sieve (silicon-to-aluminum ratio of 20:1) and the ammonium nitrate aqueous solution from step 1) were mixed at a solid-liquid ratio (g / mL) of 1:10 and stirred at 80°C for 4 hours. The solid was then recovered by filtration and washed three times with deionized water. The solid was then dried at 100°C for 16 hours. The USY molecular sieve and the ammonium nitrate aqueous solution from step 1) were mixed again at a solid-liquid ratio (g / mL) of 1:10 and stirred at 80°C for 4 hours. The solid was then recovered by filtration and washed three times with deionized water. The solid was then dried at 100°C for 16 hours. Finally, the dried solid obtained after two ion exchanges with ammonium ions was calcined at 500°C for 5 hours to obtain the hydrogen form of the USY molecular sieve.

[0140] 3) Dissolve praseodymium nitrate and cobalt nitrate in water to prepare an aqueous solution containing praseodymium ions at a concentration of 0.5 mol / L (i.e., the concentration of praseodymium nitrate is 0.5 mol / L) and cobalt ions at a concentration of 0.3 mol / L (i.e., the concentration of cobalt nitrate is 0.3 mol / L).

[0141] 4) The hydrogen-form USY molecular sieve obtained in step 2) was mixed with the aqueous solution in step 3) at a solid-liquid ratio (g / mL) of 1:10 and stirred at 80°C for 8 hours. The solid was then recovered by filtration and washed three times with deionized water. The solid was then dried at 120°C for 16 hours. Finally, the dried solid was calcined at 550°C for 4 hours to obtain the modified USY molecular sieve.

[0142] Comparative preparation example 5

[0143] The preparation method of Co / USY molecular sieve includes the following steps:

[0144] 1) Dissolve ammonium nitrate in water to prepare an ammonium nitrate aqueous solution with an ammonium ion concentration of 0.1 mol / L (i.e., an ammonium nitrate concentration of 0.1 mol / L).

[0145] 2) The USY molecular sieve (silicon-to-aluminum ratio of 20:1) and the ammonium nitrate aqueous solution from step 1) were mixed at a solid-liquid ratio (g / mL) of 1:10 and stirred at 80°C for 4 hours. The solid was then recovered by filtration and washed three times with deionized water. The solid was then dried at 100°C for 16 hours. The USY molecular sieve and the ammonium nitrate aqueous solution from step 1) were mixed again at a solid-liquid ratio (g / mL) of 1:10 and stirred at 80°C for 4 hours. The solid was then recovered by filtration and washed three times with deionized water. The solid was then dried at 100°C for 16 hours. Finally, the dried solid obtained after two ion exchanges with ammonium ions was calcined at 500°C for 5 hours to obtain the hydrogen form of the USY molecular sieve.

[0146] 3) Dissolve cobalt nitrate in water to prepare a cobalt nitrate aqueous solution with a cobalt ion concentration of 0.3 mol / L (i.e., a cobalt nitrate concentration of 0.3 mol / L).

[0147] 4) The hydrogen-form USY molecular sieve obtained in step 2) is mixed with the cobalt nitrate aqueous solution in step 3) at a solid-liquid ratio (g / mL) of 1:10 and stirred at 80°C for 6 hours. The solid is then recovered by filtration and washed three times with deionized water. The solid is then dried at 120°C for 16 hours. Finally, it is calcined at 550°C for 4 hours to obtain the modified USY molecular sieve, labeled as Co / USY molecular sieve.

[0148] Comparative preparation example 6

[0149] The preparation method of modified USY molecular sieve includes the following steps:

[0150] 1) Dissolve ammonium nitrate in water to prepare an ammonium nitrate aqueous solution with an ammonium ion concentration of 0.1 mol / L (i.e., an ammonium nitrate concentration of 0.1 mol / L).

[0151] 2) The USY molecular sieve (silicon-to-aluminum ratio of 20:1) and the ammonium nitrate aqueous solution from step 1) were mixed at a solid-liquid ratio (g / mL) of 1:10 and stirred at 80°C for 4 hours. The solid was then recovered by filtration and washed three times with deionized water. The solid was then dried at 100°C for 16 hours. The USY molecular sieve and the ammonium nitrate aqueous solution from step 1) were mixed again at a solid-liquid ratio (g / mL) of 1:10 and stirred at 80°C for 4 hours. The solid was then recovered by filtration and washed three times with deionized water. The solid was then dried at 100°C for 16 hours. Finally, the dried solid obtained after two ion exchanges with ammonium ions was calcined at 500°C for 5 hours to obtain the hydrogen form of the USY molecular sieve.

[0152] 3) Dissolve cobalt nitrate in water to prepare a cobalt nitrate aqueous solution with a cobalt ion concentration of 0.3 mol / L (i.e., a cobalt nitrate concentration of 0.3 mol / L).

[0153] 4) The hydrogen-type USY molecular sieve obtained in step 2) is mixed with the cobalt nitrate aqueous solution in step 3) at a solid-liquid ratio (g / mL) of 1:10 and stirred at 80°C for 6 hours. The solid is then recovered by filtration and washed three times with deionized water. The solid is then dried at 120°C for 16 hours. Finally, it is calcined at 550°C for 4 hours to obtain the cobalt-modified USY molecular sieve.

[0154] 5) Dissolve praseodymium nitrate in water to prepare an aqueous solution of praseodymium nitrate with a praseodymium ion concentration of 0.5 mol / L (i.e., a praseodymium nitrate concentration of 0.5 mol / L).

[0155] 6) The cobalt-modified USY molecular sieve obtained in step 4) was mixed with the praseodymium nitrate aqueous solution from step 5) at a solid-liquid ratio (g / mL) of 1:10 and stirred at 80°C for 8 hours. The solid was then recovered by filtration and washed three times with deionized water, followed by drying at 120°C for 16 hours. The molecular sieve was then mixed again with the praseodymium nitrate aqueous solution from step 5) at a solid-liquid ratio (g / mL) of 1:10 and stirred at 80°C for 8 hours. The solid was then recovered by filtration and… The solid was washed three times with deionized water and then dried at 120°C for 16 hours. Subsequently, the molecular sieve was mixed with the praseodymium nitrate aqueous solution from step 5) at a solid-liquid ratio (g / mL) of 1:10 and stirred at 80°C for 8 hours. The solid was then recovered by filtration and washed three times with deionized water, and then dried at 120°C for 16 hours. Finally, the dried solid obtained after three praseodymium ion exchange processes was calcined at 550°C for 4 hours to obtain the modified USY molecular sieve.

[0156] Synthesis Example 1

[0157] A method for synthesizing 2,6-diisopropylnaphthalene includes the following steps:

[0158] Take 10g of the PrCo / USY molecular sieve obtained in Preparation Example 1 into a 300mL high-pressure reactor, then add 100g of solid naphthalene, seal the high-pressure reactor, then purge the air into the high-pressure reactor with nitrogen to replace it, and then pressurize the high-pressure reactor to a pressure of 0.3MPa with nitrogen. Heat the high-pressure reactor, and when the temperature inside the high-pressure reactor reaches 150℃, purge 65.7g of gaseous propylene into the high-pressure reactor at a uniform rate (about 1h). Control the temperature inside the high-pressure reactor to 210℃ and the pressure to 2.0MPa, and let the propylene and naphthalene react in the high-pressure reactor for 5h, and then separate the reaction products.

[0159] The conversion rate of naphthalene and the selectivity of diisopropylnaphthalene, 2,6-diisopropylnaphthalene and 2,7-diisopropylnaphthalene were determined by gas chromatography. The results are shown in Table 1.

[0160] Synthesis Example 2

[0161] A method for synthesizing 2,6-diisopropylnaphthalene includes the following steps:

[0162] Take 6g of the PrCo / USY molecular sieve obtained in Preparation Example 1 into a 300mL high-pressure reactor, then add 100g of solid naphthalene, seal the high-pressure reactor, and then purge the air in the high-pressure reactor with nitrogen to replace it. Then pressurize the high-pressure reactor to a pressure of 0.3MPa with nitrogen and heat the high-pressure reactor. When the temperature in the high-pressure reactor reaches 150℃, purge 65.7g of gaseous propylene into the high-pressure reactor at a uniform rate (about 1h). Control the temperature in the high-pressure reactor to 230℃ and the pressure to 1.5MPa, and let the propylene and naphthalene react in the high-pressure reactor for 3h. Then separate the reaction products.

[0163] The conversion rate of naphthalene and the selectivity of diisopropylnaphthalene, 2,6-diisopropylnaphthalene and 2,7-diisopropylnaphthalene were determined by gas chromatography. The results are shown in Table 1.

[0164] Synthesis Example 3

[0165] A method for synthesizing 2,6-diisopropylnaphthalene includes the following steps:

[0166] Take 5g of the SmCo / USY molecular sieve obtained in Preparation Example 2 into a 300mL high-pressure reactor, then add 100g of naphthalene solid, seal the high-pressure reactor, and then purge the air in the high-pressure reactor with nitrogen gas to replace it. Then pressurize the high-pressure reactor to a pressure of 0.3MPa with nitrogen gas and heat the high-pressure reactor. When the temperature in the high-pressure reactor reaches 150℃, purge 65.7g of gaseous propylene into the high-pressure reactor at a uniform rate (about 1h). Control the temperature in the high-pressure reactor to 230℃ and the pressure to 1.5MPa, and let the propylene and naphthalene react in the high-pressure reactor for 3h. Then separate the reaction products.

[0167] The conversion rate of naphthalene and the selectivity of diisopropylnaphthalene, 2,6-diisopropylnaphthalene and 2,7-diisopropylnaphthalene were determined by gas chromatography. The results are shown in Table 1.

[0168] Synthesis Example 4

[0169] Take 3g of the PrSmCo / USY molecular sieve obtained in Preparation Example 3 into a 300mL high-pressure reactor, then add 100g of naphthalene solid, seal the high-pressure reactor, and then purge the air in the high-pressure reactor with nitrogen gas to replace it. Then pressurize the high-pressure reactor to a pressure of 0.3MPa with nitrogen gas and heat the high-pressure reactor. When the temperature in the high-pressure reactor reaches 150℃, purge 65.7g of gaseous propylene into the high-pressure reactor at a uniform rate (about 1h). Control the temperature in the high-pressure reactor to 230℃ and the pressure to 2.5MPa, and let the propylene and naphthalene react in the high-pressure reactor for 3h. Then separate the reaction products.

[0170] The conversion rate of naphthalene and the selectivity of diisopropylnaphthalene, 2,6-diisopropylnaphthalene and 2,7-diisopropylnaphthalene were determined by gas chromatography. The results are shown in Table 1.

[0171] Synthesis Example 5

[0172] Take 8g of the modified USY molecular sieve obtained in Preparation Example 4 into a 300mL high-pressure reactor, then add 100g of naphthalene solid, seal the high-pressure reactor, and then purge the air in the high-pressure reactor with nitrogen gas to replace it. Then pressurize the high-pressure reactor to a pressure of 0.3MPa with nitrogen gas and heat the high-pressure reactor. When the temperature in the high-pressure reactor reaches 150℃, purge 65.7g of gaseous propylene into the high-pressure reactor at a uniform rate (about 1h). Control the temperature in the high-pressure reactor to 230℃ and the pressure to 1.5MPa, and let the propylene and naphthalene react in the high-pressure reactor for 3h. Then separate the reaction products.

[0173] The conversion rate of naphthalene and the selectivity of diisopropylnaphthalene, 2,6-diisopropylnaphthalene and 2,7-diisopropylnaphthalene were determined by gas chromatography. The results are shown in Table 1.

[0174] Synthesis Example 6

[0175] The synthesis method is the same as that in Synthesis Example 1, except that the PrCo / USY molecular sieve is replaced with the modified USY molecular sieve obtained in Preparation Example 5.

[0176] The conversion rate of naphthalene and the selectivity of diisopropylnaphthalene, 2,6-diisopropylnaphthalene and 2,7-diisopropylnaphthalene were determined by gas chromatography. The results are shown in Table 1.

[0177] Synthetic Comparative Example 1

[0178] The synthesis method was the same as in Synthesis Example 1, except that the PrCo / USY molecular sieve was replaced with the USY molecular sieve obtained in Comparative Preparation Example 1.

[0179] The conversion rate of naphthalene and the selectivity of diisopropylnaphthalene, 2,6-diisopropylnaphthalene and 2,7-diisopropylnaphthalene were determined by gas chromatography. The results are shown in Table 1.

[0180] Synthetic Comparative Example 2

[0181] The synthesis method was the same as in Synthesis Example 1, except that the PrCo / USY molecular sieve was replaced with the hydrogen-form USY molecular sieve obtained in Comparative Preparation Example 2.

[0182] The conversion rate of naphthalene and the selectivity of diisopropylnaphthalene, 2,6-diisopropylnaphthalene and 2,7-diisopropylnaphthalene were determined by gas chromatography. The results are shown in Table 1.

[0183] Synthetic Comparative Example 3

[0184] The synthesis method was the same as in Synthesis Example 1, except that the PrCo / USY molecular sieve was replaced with the Pr / USY molecular sieve obtained in Comparative Preparation Example 3.

[0185] The conversion rate of naphthalene and the selectivity of diisopropylnaphthalene, 2,6-diisopropylnaphthalene and 2,7-diisopropylnaphthalene were determined by gas chromatography. The results are shown in Table 1.

[0186] Synthetic Comparative Example 4

[0187] The synthesis method was the same as in Synthesis Example 1, except that the PrCo / USY molecular sieve was replaced with the modified USY molecular sieve obtained in Comparative Preparation Example 4.

[0188] The conversion rate of naphthalene and the selectivity of diisopropylnaphthalene, 2,6-diisopropylnaphthalene and 2,7-diisopropylnaphthalene were determined by gas chromatography. The results are shown in Table 1.

[0189] Synthetic Comparative Example 5

[0190] The synthesis method was the same as in Synthesis Example 1, except that the PrCo / USY molecular sieve was replaced with the Co / USY molecular sieve obtained in Comparative Preparation Example 5.

[0191] The conversion rate of naphthalene and the selectivity of diisopropylnaphthalene, 2,6-diisopropylnaphthalene and 2,7-diisopropylnaphthalene were determined by gas chromatography. The results are shown in Table 1.

[0192] Synthetic Comparative Example 6

[0193] The synthesis method was the same as in Synthesis Example 1, except that the PrCo / USY molecular sieve was replaced with the modified USY molecular sieve obtained in Comparative Preparation Example 6.

[0194] The conversion rate of naphthalene and the selectivity of diisopropylnaphthalene, 2,6-diisopropylnaphthalene and 2,7-diisopropylnaphthalene were determined by gas chromatography. The results are shown in Table 1.

[0195] Table 1. Conversion rate of naphthalene and selectivity of 2,6-diisopropylnaphthalene

[0196]

[0197] Repeated Synthesis Examples

[0198] A method for synthesizing 2,6-diisopropylnaphthalene includes the following steps:

[0199] (1) Take 6g of the PrCo / USY molecular sieve obtained in Preparation Example 1 into a 300mL high-pressure reactor, then add 100g of naphthalene solid, seal the high-pressure reactor, then introduce nitrogen into the high-pressure reactor to replace the air in the high-pressure reactor, then pressurize the high-pressure reactor to a pressure of 0.3MPa with nitrogen, heat the high-pressure reactor, and when the temperature in the high-pressure reactor reaches 150℃, introduce 65.7g of gaseous propylene into the high-pressure reactor at a uniform rate (about 1h), control the temperature in the high-pressure reactor to 230℃ and the pressure to 1.5MPa, and let the propylene and naphthalene react in the high-pressure reactor for 3h. Then separate the reaction products, and determine the conversion rate of naphthalene and the selectivity of diisopropylnaphthalene, 2,6-diisopropylnaphthalene and 2,7-diisopropylnaphthalene by gas chromatography. The results are shown in Table 2.

[0200] (2) After the reaction in step (1) is completed, the PrCo / USY molecular sieve in the high-pressure reactor is separated and put back into the 300mL high-pressure reactor. Then, 100g of naphthalene solid is added, the high-pressure reactor is sealed, and nitrogen is introduced into the high-pressure reactor to replace the air in the high-pressure reactor. Then, nitrogen is used to pressurize the pressure in the high-pressure reactor to 0.3MPa. The high-pressure reactor is heated. When the temperature in the high-pressure reactor reaches 150℃, 65.7g of gaseous propylene is introduced into the high-pressure reactor at a uniform rate (about 1h). The temperature in the high-pressure reactor is controlled at 230℃ and the pressure is 1.5MPa. The propylene and naphthalene react in the high-pressure reactor for 3h. Then, the reaction products are separated. The conversion rate of naphthalene and the selectivity of diisopropylnaphthalene, 2,6-diisopropylnaphthalene and 2,7-diisopropylnaphthalene are determined by gas chromatography. The results are shown in Table 2.

[0201] (3) Repeat step (2) to separate the PrCo / USY molecular sieve from the high-pressure reactor after the previous round of catalytic reaction for use in the next round of catalytic reaction. The PrCo / USY molecular sieve obtained in Preparation Example 1 was used to catalyze the synthesis of 2,6-diisopropylnaphthalene from naphthalene and propylene ten times. The conversion rate of naphthalene and the selectivity of diisopropylnaphthalene, 2,6-diisopropylnaphthalene and 2,7-diisopropylnaphthalene after each round of synthesis reaction were determined by gas chromatography. The results are shown in Table 2.

[0202] Table 2. Effect of reusing the catalyst (PrCo / USY molecular sieve) ten times.

[0203]

[0204]

[0205] It should be noted that the embodiments described above are only for explaining the present invention and do not constitute any limitation on the present invention. The present invention has been described with reference to embodiments, but it should be understood that the terms used therein are descriptive and explanatory terms, not limiting terms. Modifications can be made to the present invention within the scope of the claims, and revisions can be made to the present invention without departing from the scope and spirit of the present invention. Although the present invention described herein relates to specific methods, materials, and embodiments, it does not mean that the present invention is limited to the specific examples disclosed herein; on the contrary, the present invention can be extended to all other methods and applications having the same function.

Claims

1. A method for preparing modified USY molecular sieve, characterized in that, The preparation method includes mixing USY molecular sieve sequentially with a solution containing ammonium ions, a solution containing rare earth metal ions, and a solution containing cobalt ions, and then carrying out an ion exchange reaction in the solution.

2. The preparation method according to claim 1, characterized in that, The ammonium-containing solution is obtained by dissolving an ammonium salt in water; preferably, the ammonium salt includes at least one of ammonium nitrate, ammonium chloride, and ammonium sulfate, with ammonium nitrate being the most preferred. And / or, the solution containing rare earth metal ions is obtained by dissolving a water-soluble salt of a rare earth metal in water; preferably, the water-soluble salt of the rare earth metal includes at least one of praseodymium and / or samarium nitrate, sulfate, and hydrochloride. And / or, the cobalt ion-containing solution is obtained by dissolving a cobalt salt in water; preferably, the cobalt salt includes at least one of cobalt nitrate, cobalt sulfate, and cobalt chloride.

3. The preparation method according to claim 1 or 2, characterized in that, The concentration of ammonium ions in the solution is 0.05–0.15 mol / L; And / or, the solid-liquid ratio of the USY molecular sieve mixed with the solution containing ammonium ions is 1 g: (8-20) mL; And / or, the temperature for the ion exchange reaction between USY molecular sieve and ammonium-containing solution is 70–90°C and the time is 4–18 h; preferably, USY molecular sieve is mixed with ammonium-containing solution 2–3 times consecutively and the ion exchange reaction is carried out in solution, with each reaction lasting 2–6 h; more preferably, after each reaction, the solid is recovered, washed with water, and dried at 80–120°C for 14–18 h. And / or, the concentration of rare earth metal ions in the solution containing rare earth metal ions is 0.1–1.5 mol / L, preferably 0.4–1.0 mol / L; And / or, the solid-liquid ratio of the USY molecular sieve mixed with the solution containing rare earth metal ions is 1g:(5-30)mL, preferably 1g:(10-20)mL; And / or, the temperature for the ion exchange reaction between USY molecular sieve and solution containing rare earth metal ions is 70-90°C and the time is 12-40 h; preferably, USY molecular sieve is mixed with solution containing rare earth metal ions 2-4 times consecutively and the ion exchange reaction is carried out in solution, each reaction lasting 6-10 h; more preferably, after each reaction, the solid is recovered, washed with water, and dried at 100-140°C for 14-18 h. And / or, the concentration of cobalt ions in the cobalt ion-containing solution is 0.05–2 mol / L, preferably 0.1–1.0 mol / L; And / or, the solid-liquid ratio of the USY molecular sieve mixed with the cobalt ion-containing solution is 1 g:(5-50) mL, preferably 1 g:(10-30) mL; And / or, the temperature for the ion exchange reaction between USY molecular sieve and a solution containing cobalt ions is 70–90 °C and the time is 4–8 h.

4. The preparation method according to any one of claims 1 to 3, characterized in that, The preparation method further includes drying and calcining the USY molecular sieve after ion exchange with ammonium ions; preferably, the drying conditions include a temperature of 80-120°C and a time of 14-18h, and / or the calcination conditions include a temperature of 450-550°C and a time of 3-7h. And / or, the preparation method further includes drying and calcining the USY molecular sieve after ion exchange with rare earth metals; preferably, the drying conditions include a temperature of 100-140°C and a time of 14-18h, and / or the calcination conditions include a temperature of 500-600°C and a time of 2-6h. And / or, the preparation method further includes drying and calcining the USY molecular sieve after ion exchange with cobalt ions; preferably, the drying conditions include a temperature of 100-140°C and a time of 14-18 h, and / or the calcination conditions include a temperature of 500-600°C and a time of 2-6 h.

5. The preparation method according to any one of claims 1 to 4, characterized in that, The silica-alumina ratio of the USY molecular sieve is (5-200):1, preferably (5-100):1; And / or, the preparation method further includes controlling the mass percentage of the rare earth metal in the modified USY molecular sieve to be 0.2wt% to 8wt% based on the total mass of the modified USY molecular sieve, preferably 1wt% to 5wt%. And / or, the preparation method further includes controlling the mass percentage of cobalt in the modified USY molecular sieve to be 0.2wt% to 8wt% based on the total mass of the modified USY molecular sieve, preferably 0.5wt% to 3wt%; And / or, the preparation method further includes controlling the mass ratio of the rare earth metal in the modified USY molecular sieve to the mass ratio of the cobalt in the modified USY molecular sieve to be (0.5-4):1; preferably (1-3):

1.

6. The modified USY molecular sieve prepared by any one of claims 1 to 5.

7. The application of the modified USY molecular sieve according to claim 6 in catalytic alkylation reactions, especially in the catalytic synthesis of 2,6-diisopropylnaphthalene.

8. A method for synthesizing 2,6-diisopropylnaphthalene, characterized in that, The method includes using propylene and naphthalene source as raw materials to synthesize 2,6-diisopropylnaphthalene using the modified USY molecular sieve catalytic raw material as described in claim 6; preferably, the naphthalene source is naphthalene and / or 2-isopropylnaphthalene, and / or, the molar mass ratio of the naphthalene source to propylene is 1:(1-5), preferably 1:(1-2.2).

9. The method according to claim 8, characterized in that, In the synthesis reaction, the amount of the modified USY molecular sieve is 0.2% to 15% of the naphthalene source mass, preferably 0.5% to 10%; And / or, the temperature of the synthesis reaction is 150–300°C, preferably 170–250°C; And / or, the pressure of the synthesis reaction is 0.5–6.0 MPa, preferably 1–4.0 MPa; And / or, the reaction time of the raw materials in the reactor during the synthesis reaction is 1 to 10 hours, preferably 2 to 8 hours; And / or, the reactor for the synthesis reaction is any one of a batch reactor, a fixed-bed reactor, a slurry-bed reactor, or a microchannel reactor.

10. The application of the method of claim 8 or 9 in the industrial production of 2,6-diisopropylnaphthalene and the 2,6-diisopropylnaphthalene produced by the application.

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