Molecular sieve catalyst, its preparation method and application

Abstract

This invention provides a molecular sieve catalyst, its preparation method, and its application, relating to the field of molecular sieve catalysts. The preparation method of the molecular sieve catalyst provided by this invention includes the following steps: Step 1: Obtaining a mixture comprising a Mg-containing precursor, a Ce-containing precursor, a dispersant, and water; Step 2: Mixing the mixture obtained in Step 1 with a mordenite molecular sieve and subjecting it to a pressurized hydrothermal reaction to obtain the molecular sieve catalyst. The preparation method of the molecular sieve catalyst provided by this invention involves mixing a dispersant with a metal precursor and impregnating it with a molecular sieve to uniformly disperse magnesium and cerium on the inner and outer surfaces of the molecular sieve; then, using an impregnation method combined with a pressurized hydrothermal method, Mg and Ce are successfully introduced into the molecular sieve framework, further adjusting the acidity of the mordenite molecular sieve. This catalyst exhibits high activity and selectivity when applied to the production of diisopropylnaphthalene from monoisopropylnaphthalene and propylene.

Description

Technical Field

[0001] This invention relates to the field of molecular sieve catalysts, specifically to a molecular sieve catalyst, its preparation method, and its application. Background Technology

[0002] Alkyl naphthalenes possess excellent thermal oxidation stability, hydrolytic stability, good additive solubility, and demulsification properties, making them widely used in hydraulic oils, gear oils, heat transfer oils, transformer oils, compressor oils, and liquid crystal displays. Isopropyl naphthalene series products can be used as heat transfer oils. Isopropyl naphthalene series heat transfer oils have advantages such as being odorless, non-corrosive to metals, having good thermal stability, excellent low-temperature performance, and being recyclable. The isopropyl naphthalene series mainly includes monoisopropyl naphthalene, diisopropyl naphthalene, and triisopropyl naphthalene. Diisopropyl naphthalene (DIPN) is an important fine chemical raw material for synthesizing naphthalene-containing polymers, and it is also a high-performance high-temperature synthetic heat transfer oil and electrical insulating oil. In particular, 2,6-diisopropyl naphthalene is a major raw material for synthesizing polyethylene naphthalate (PEN). PEN is a novel high-performance polyester material with wide applications in instruments, fibers, insulation materials, aerospace, and nuclear energy materials. Therefore, the synthesis of diisopropyl naphthalene is crucial.

[0003] The preparation of diisopropylnaphthalene primarily relies on the alkylation of naphthalene with propylene, with molecular sieves commonly used as catalysts. This method theoretically yields over ten mono- and poly-substituted products, and propylene itself undergoes polymerization, generating byproducts. Using monoisopropylnaphthalene, such as 1-isopropylnaphthalene or 2-isopropylnaphthalene, generated from the reaction of naphthalene and propylene as a raw material for further alkylation to prepare diisopropylnaphthalene offers advantages such as lower input costs and a simpler process.

[0004] Currently, the focus of research is on developing process routes for the preparation of diisopropylnaphthalene by the alkylation of monoisopropylnaphthalene and exploring novel catalyst reaction technologies. Summary of the Invention

[0005] Based on the above analysis, the present invention aims to provide a molecular sieve catalyst, its preparation method and application, to solve at least one of the following existing technical problems: improving the conversion rate of monoisopropylnaphthalene and improving the selectivity of diisopropylnaphthalene.

[0006] The objective of this invention is mainly achieved through the following technical solutions:

[0007] In a first aspect, the present invention provides a method for preparing a molecular sieve catalyst, wherein the molecular sieve catalyst is a magnesium and cerium modified mordenite molecular sieve catalyst, and the preparation method includes the following steps:

[0008] Step 1: Obtain a mixture comprising a Mg-containing precursor, a Ce-containing precursor, a dispersant, and water;

[0009] Step 2: Mix the mixture obtained in Step 1 with mordenite molecular sieve and carry out a hydrothermal reaction under pressure to obtain the molecular sieve catalyst.

[0010] Preferably, in step 1, the dispersant includes at least one of ethylenediamine and urea.

[0011] Preferably, in step 1, the molar ratio of the amount of the dispersant to the total amount of the Mg-containing precursor (calculated as Mg) and the Ce-containing precursor (calculated as Ce) is 0.5-1.

[0012] Preferably, in step 2, the reaction pressure is 1-3 MPa.

[0013] Preferably, in step 2, the reaction temperature is 100-150℃.

[0014] Preferably, the total amount of Mg-containing precursors (calculated as Mg) and Ce-containing precursors (calculated as Ce) to the mass ratio of the mordenite molecular sieve is (2-20):(80-98), more preferably (5-15):(85-95), and even more preferably (10-15):(85-90).

[0015] Preferably, the mass ratio of the Mg-containing precursor (calculated as Mg) to the mordenite molecular sieve is (1-10):(90-99), more preferably (5-10):(90-95).

[0016] Preferably, the mass ratio of Ce-containing precursor to the mordenite molecular sieve, based on the total weight of the catalyst, is (1-10):(90-99), more preferably (5-10):(90-95).

[0017] Preferably, in step 1, the Mg-containing precursor includes at least one of Mg nitrate, acetate, halide, sulfate, and acetate; the Ce-containing precursor includes at least one of Ce nitrate, acetate, halide, sulfate, and acetate; the mordenite molecular sieve is a hydrogen-type mordenite molecular sieve; more preferably, the silica-alumina ratio of the mordenite molecular sieve is 10-30.

[0018] Secondly, the present invention provides a molecular sieve catalyst prepared by the preparation method described above.

[0019] Preferably, the total mass percentage of Mg and Ce, based on the total weight of the catalyst, is 2 wt%-20 wt%, more preferably 5 wt%-15 wt%, and even more preferably 10 wt%-15 wt%.

[0020] Preferably, the mass percentage of Mg is 1 wt%-10 wt%, more preferably 5 wt%-10 wt%, based on the total weight of the catalyst.

[0021] Preferably, the mass percentage of Ce, based on the total weight of the catalyst, is 1 wt% to 10 wt%, more preferably 5 wt% to 10 wt%.

[0022] Thirdly, the present invention provides an application of the molecular sieve catalyst described above in a method for preparing diisopropylnaphthalene.

[0023] Fourthly, the present invention provides a method for preparing diisopropylnaphthalene, the method comprising the steps of: obtaining a mixture comprising propylene and monoisopropylnaphthalene, reacting it in the presence of the molecular sieve catalyst to obtain diisopropylnaphthalene.

[0024] Preferably, in the preparation method of diisopropylnaphthalene, the reaction temperature is 150-300℃; the reaction pressure is 1.0-3.5MPa; the reaction space velocity is 1000-12000mL / h / g; the molar ratio of monoisopropylnaphthalene to propylene is 1:(1.5-2.0); and the amount of the molecular sieve catalyst is 0.5-10wt% of the mass of monoisopropylnaphthalene.

[0025] Beneficial effects:

[0026] The method for preparing the molecular sieve catalyst provided by this invention involves mixing a dispersant with a metal precursor and impregnating the molecular sieve to uniformly disperse magnesium and cerium on the inner and outer surfaces of the molecular sieve. Then, using an impregnation method combined with a pressurized hydrothermal method, Mg and Ce are successfully introduced into the molecular sieve framework, further adjusting the acidity of the mordenite molecular sieve and significantly improving the alkylation activity of the obtained catalyst. This catalyst exhibits high activity and selectivity when applied to the production of diisopropylnaphthalene from monoisopropylnaphthalene and propylene. Detailed Implementation

[0027] The following provides a detailed description of specific embodiments of the present invention. It should be understood that the specific embodiments described herein are for illustrative and explanatory purposes only and are not intended to limit the scope of the invention.

[0028] In this invention, Mg refers to the chemical element magnesium, and Ce refers to the chemical element cerium.

[0029] In a first aspect, the present invention provides a method for preparing a molecular sieve catalyst, wherein the molecular sieve catalyst is a magnesium and cerium modified mordenite molecular sieve catalyst, and the preparation method includes the following steps:

[0030] Step 1: Obtain a mixture comprising a Mg-containing precursor, a Ce-containing precursor, a dispersant, and water;

[0031] Step 2: Mix the mixture obtained in Step 1 with mordenite molecular sieve and carry out a hydrothermal reaction under pressure;

[0032] Step 3: Filtration, washing, drying and calcination to obtain magnesium and cerium modified mordenite molecular sieve catalyst.

[0033] In one specific embodiment of the present invention, in step 1, the dispersant is selected from at least one of ethylenediamine and urea.

[0034] In one specific embodiment of the present invention, in step 1, the molar ratio of the dispersant to the total amount of Mg-containing precursor (calculated as Mg) and Ce-containing precursor (calculated as Ce) is 0.5-1, for example, 0.6, 0.7, 0.8, 0.9, etc. It should be noted that when the molar ratio of the dispersant to the total amount of Mg and Ce is less than 0.5, the amount of dispersant is insufficient, resulting in poor dispersion and consequently poor conversion of monoisopropylnaphthalene and selectivity of diisopropylnaphthalene. When the molar ratio of the dispersant to the total amount of Mg and Ce is greater than 1, it will affect the physicochemical properties of the molecular sieve, such as acid sites and pore size distribution, leading to poor conversion of monoisopropylnaphthalene and selectivity of diisopropylnaphthalene.

[0035] In one specific embodiment of the present invention, in step 1, at least one of nitrate, acetate, halide, sulfate, and acetate containing Mg as the Mg precursor is used.

[0036] In one specific embodiment of the present invention, in step 1, at least one of nitrate, acetate, halide, sulfate, and acetate containing Ce as the Ce precursor is included.

[0037] In a specific embodiment of the present invention, in step 2, the mordenite molecular sieve is a hydrogen-type mordenite molecular sieve (HM) with a silicon-to-aluminum ratio of 10-30.

[0038] In one specific embodiment of the present invention, the reaction pressure in step 2 is 1-3 MPa, such as 1.5, 2, or 2.5 MPa; the reaction temperature is 100-150°C, such as 110, 120, 130, or 140°C; and the reaction time is 4-6 hours. It should be noted that in step 2, the reaction pressure and temperature cannot be too high or too low. If the temperature or pressure is too low, Mg and Ce cannot replace Al in the molecular sieve framework, leading to a decrease in the conversion rate of monoisopropylnaphthalene and a decrease in the selectivity of diisopropylnaphthalene. If the temperature or pressure is too high, it will cause damage to the molecular sieve framework structure, potentially leading to its collapse.

[0039] In one specific embodiment of the present invention, in step 2, nitrogen gas is introduced to pressurize the gas.

[0040] In one specific embodiment of the present invention, in step 3, the drying temperature is 80-120℃ and the drying time is 10-12h; the calcination temperature is 500-600℃ and the calcination time is 3-6h.

[0041] The method for preparing the molecular sieve catalyst provided by this invention involves mixing a dispersant with a metal precursor and impregnating the molecular sieve to uniformly disperse the metal on the inner and outer surfaces of the molecular sieve. Then, using a pressurized hydrothermal method, Mg and Ce are successfully introduced into the molecular sieve framework to replace Al, effectively regulating the distribution of Al in the framework (significantly reducing aluminum content and creating larger spaces for aluminum in the intersecting channels). The reduction in Al weakens the acidity of the molecular sieve and reduces carbon deposition. Furthermore, Mg and Ce are confined within the pore framework of the molecular sieve HM, forming stable interfacial bonds. Charge on Ce transfers to Mg, exhibiting a strong Ce-Mg electronic interaction and producing a bimetallic synergistic effect. This effect leads to electron transfer from Mg-Ce to oxygen atoms in the mordenite molecular sieve framework, further modulating the acidity of the mordenite molecular sieve, resulting in higher alkylation activity and selectivity of the catalyst. This catalyst demonstrates high activity and selectivity in the production of diisopropylnaphthalene from monoisopropylnaphthalene and propylene.

[0042] As a specific embodiment of the present invention, the total amount of Mg-containing precursor (calculated as Mg) and Ce-containing precursor (calculated as Ce) to the mass ratio of the mordenite molecular sieve is (2-20):(80-98), preferably (5-15):(85-95), and more preferably (10-15):(85-90).

[0043] As a specific embodiment of the present invention, the mass ratio of the Mg-containing precursor (calculated as Mg) to the mordenite molecular sieve is (1-10):(90-99), preferably (5-10):(90-95).

[0044] As a specific embodiment of the present invention, the mass ratio of the Ce-containing precursor to the mordenite molecular sieve is (1-10):(90-99), preferably (5-10):(90-95).

[0045] Secondly, the present invention provides a magnesium and cerium modified mordenite molecular sieve catalyst prepared by the above preparation method.

[0046] As a specific embodiment of the present invention, the total amount of Mg and Ce, based on the total weight of the catalyst, accounts for 2wt%-20wt% of the catalyst weight, such as 3wt%, 4wt%, 5wt%, 6wt%, 7wt%, 8wt%, 9wt%, 10wt%, 11wt%, 12wt%, 13wt%, 14wt%, 15wt%, 16wt%, 17wt%, 18wt%, 19wt%, etc., preferably 5wt%-15wt%, more preferably 10wt%-15wt%; the mordenite molecular sieve catalyst accounts for 80wt%-98wt% of the catalyst weight, preferably 85wt%-95wt%, more preferably 85wt%-90wt%.

[0047] As a specific embodiment of the present invention, the Mg content accounts for 1wt%-10wt% of the total weight of the catalyst, for example 2wt%, 3wt%, 4wt%, 5wt%, 6wt%, 7wt%, 8wt%, 9wt%, etc., preferably 5wt%-10wt%.

[0048] As a specific embodiment of the present invention, the Ce content accounts for 1wt%-10wt% of the total weight of the catalyst, for example 2wt%, 3wt%, 4wt%, 5wt%, 6wt%, 7wt%, 8wt%, 9wt%, etc., preferably 5wt%-10wt%.

[0049] Thirdly, the present invention provides an application of the above-mentioned molecular sieve catalyst in a method for preparing diisopropylnaphthalene.

[0050] Fourthly, the present invention provides a method for preparing diisopropylnaphthalene, comprising the steps of: obtaining a mixture comprising propylene and monoisopropylnaphthalene, and, under the condition of the presence of the above-mentioned molecular sieve catalyst, introducing pressurized gas and heating to carry out a reaction to obtain diisopropylnaphthalene.

[0051] It should be noted that the preparation method of diisopropylnaphthalene provided by the present invention uses a metal-modified mordenite molecular sieve catalyst. The mordenite molecular sieve catalyst modified with Mg and Ce metals exhibits high activity in alkylation, especially in the production of diisopropylnaphthalene from monoisopropylnaphthalene and propylene, showing high activity and selectivity for diisopropylnaphthalene.

[0052] In one specific embodiment of the present invention, the diisopropylnaphthalene preparation method is carried out in a reactor, which includes at least one of a fixed-bed reactor, a fluidized-bed reactor, and a batch reactor.

[0053] In one specific embodiment of the present invention, the reaction temperature in the method for preparing diisopropylnaphthalene is 150-300℃, the reaction pressure is 1.0-3.5MPa, the reaction space velocity is 1000-12000mL / h / g, and the reaction stirring speed is 500-1000r / min.

[0054] In one specific embodiment of the present invention, in the method for preparing diisopropylnaphthalene, the molar ratio of monoisopropylnaphthalene to propylene is 1:(1.5-2.0).

[0055] In one specific embodiment of the present invention, in the method for preparing diisopropylnaphthalene, the amount of the molecular sieve catalyst is 0.5wt%-10wt% of the mass of monoisopropylnaphthalene.

[0056] In one specific embodiment of the present invention, in the method for preparing diisopropylnaphthalene, the molecular sieve catalyst particles have a size of 40-60 mesh.

[0057] In one specific embodiment of the present invention, in the method for preparing diisopropylnaphthalene, monoisopropylnaphthalene includes at least one of 1-isopropylnaphthalene and 2-isopropylnaphthalene.

[0058] It should be noted that the molecular sieve catalyst, its preparation method, and its application provided by this invention have the following advantages:

[0059] (1) The molecular sieve catalyst provided by the present invention has a simple preparation method, easy-to-control conditions, and high reproducibility.

[0060] (2) The molecular sieve catalyst provided by the present invention does not contain precious metals, which can reduce the cost of catalyst preparation for the production of diisopropylnaphthalene;

[0061] (3) The molecular sieve catalyst provided by the present invention does not contain any components that pollute the environment and is an environmentally friendly catalyst;

[0062] (4) The molecular sieve catalyst provided by the present invention has higher catalytic activity and diisopropylnaphthalene selectivity in the production of diisopropylnaphthalene compared with the unmodified catalyst.

[0063] (5) The molecular sieve catalyst provided by the present invention has higher catalytic activity and diisopropylnaphthalene selectivity in the production of diisopropylnaphthalene compared with the catalyst without dispersant.

[0064] (6) The molecular sieve catalyst provided by the present invention does not use organic solvents such as cyclohexane in the production of diisopropylnaphthalene, which simplifies the separation process and reduces costs.

[0065] The following detailed description of preferred embodiments of the present invention illustrates the principles of the invention and is not intended to limit the scope of the invention.

[0066] Unless otherwise specified, the raw materials and hydrogen-type mordenite molecular sieves used in the embodiments of this application were all obtained through commercial channels, with the hydrogen-type mordenite molecular sieves purchased from the Nankai University Catalyst Factory.

[0067] The formula for calculating the conversion rate (X) of monoisopropylnaphthalene is: X = (n0 - n1) / n0

[0068] Where: n0: the amount of monoisopropylnaphthalene added before the reaction.

[0069] n1: Amount of monoisopropylnaphthalene after the reaction

[0070] The formula for calculating the selectivity (S) of diisopropylnaphthalene is: S = m² / (m 2+ m 3+ m4)

[0071] Where: m2: the amount of all diisopropylnaphthalene produced.

[0072] m3: The amount of all triisopropylnaphthalene produced

[0073] m4: The amount of all tetraisopropylnaphthalene produced

[0074] Product qualitative analysis: To determine the peak assignments, the chromatographic retention times of each substance were determined using a pure substance injection method. Naphthalene, 2-isopropylnaphthalene, and 2,6-diisopropylnaphthalene were used to determine the retention times of the pure substances. Furthermore, the composition of the products resulting from the alkylation of monoisopropylnaphthalene with propylene was investigated using gas chromatography / mass spectrometry (GC / MS), combined with computer mass spectrometry library searching and manual spectral analysis.

[0075] Quantitative Analysis: Literature indicates that all isopropylnaphthalened derivatives of naphthalene possess the same response factor. Therefore, pure naphthalene, 2-isopropylnaphthalene, and 2,6-diisopropylnaphthalene were used to determine the GC response factor. Peak area correction and normalization were employed for quantitative determination of various samples.

[0076] Example 1

[0077] (1) Catalyst preparation method

[0078] Step 1: Weigh 0.53g of precursor Mg(NO3)2·6H2O, 0.15g of Ce(NO3)3·6H2O and 0.12g of ethylenediamine (the molar ratio of Mg to Ce is 5.8, and the molar ratio of ethylenediamine to the total amount of Mg and Ce is 0.8) and dissolve them in 20mL of deionized water. Stir the mixed solution magnetically at room temperature for 10min at a speed of 500r / min to form a mixed solution.

[0079] Step 2: Weigh 4.90g of hydrogen-type mordenite molecular sieve (HM) (silicon-to-aluminum ratio of 15) and add it to the mixed solution. Stir at room temperature for 30 minutes at a speed of 500 r / min. Then transfer it to a high-pressure hydrothermal reactor, add nitrogen gas at 2 MPa, and react at 120℃ for 4 hours.

[0080] Step 3: Remove the product at room temperature, filter and wash with water, and dry at 100℃ for 12 hours; calcine at 550℃ for 5 hours. A modified mordenite molecular sieve catalyst of 1wt% Mg and 1wt% Ce (based on the total weight of the catalyst) is obtained, denoted as 1Mg-1Ce / HM.

[0081] (2) Application of catalysts

[0082] The prepared 1Mg-1Ce / HM catalyst was ground, compressed, and shaped to 40-60 mesh. 3g of the shaped catalyst was added to a 300mL reactor, followed by 50g of 2-isopropylnaphthalene for the preparation of diisopropylnaphthalene. Nitrogen gas was introduced at 1MPa and then released to purge air. The temperature was programmed to rise to 150℃ at a rate of 10℃ / min. Then, 24.57g of propylene gas (molar ratio of 2-isopropylnaphthalene:C3H8 = 1:2) was introduced. Timing was started at 180℃, and the reaction was carried out for 5 hours. Gas chromatography analysis was performed on samples. The conversion rate of 2-isopropylnaphthalene was 95.2%, and the selectivity for diisopropylnaphthalene was 70.5%.

[0083] Example 2

[0084] (1) Catalyst preparation method

[0085] Step 1: Weigh 2.64g of precursor Mg(NO3)2·6H2O, 0.77g of Ce(NO3)3·6H2O and 0.58g of ethylenediamine (the molar ratio of Mg to Ce is 5.8, and the molar ratio of ethylenediamine to the total amount of Mg and Ce is 0.8) and dissolve them in 20mL of deionized water. Stir the mixed solution magnetically at room temperature for 10min at a speed of 500r / min to form a mixed solution.

[0086] Step 2: Weigh 4.50g of hydrogen-type mordenite molecular sieve (HM) (silicon-to-aluminum ratio of 15) and add it to the mixed solution. Stir at room temperature for 30 minutes at a speed of 500 r / min. Then transfer it to a high-pressure hydrothermal reactor, add nitrogen gas at 2 MPa, and react at 120℃ for 4 hours.

[0087] Step 3: Remove the product at room temperature, filter and wash with water, and dry at 100℃ for 12 hours; calcine at 550℃ for 5 hours. A modified mordenite molecular sieve catalyst with 5wt% Mg and 5wt% Ce (based on the total weight of the catalyst) is obtained, denoted as 5Mg-5Ce / HM.

[0088] (2) Application of catalysts

[0089] The prepared 5Mg-5Ce / HM catalyst was ground, compressed, and shaped to 40-60 mesh. 3g of the shaped catalyst was added to a 300mL reactor, followed by 50g of 2-isopropylnaphthalene for the preparation of diisopropylnaphthalene. Nitrogen gas was introduced at 1MPa and then released to purge air. The temperature was programmed to rise to 150℃ at a rate of 10℃ / min. Then, 24.57g of propylene gas (molar ratio of 2-monoisopropylnaphthalene:C3H8 = 1:2) was introduced. Timing was started at 180℃, and the reaction was carried out for 5 hours. Gas chromatography analysis was performed on samples. The conversion rate of 2-monoisopropylnaphthalene was 96.2%, and the selectivity for diisopropylnaphthalene was 73.1%.

[0090] Example 3

[0091] (1) Catalyst preparation method

[0092] Step 1: Weigh 2.64g of precursor Mg(NO3)2·6H2O, 1.55g of Ce(NO3)3·6H2O and 0.67g of ethylenediamine (the molar ratio of Mg to Ce is 2.9, and the molar ratio of ethylenediamine to the total amount of Mg and Ce is 0.8) and dissolve them in 20mL of deionized water. Stir the mixed solution magnetically at room temperature for 10min at a speed of 500r / min to form a mixed solution.

[0093] Step 2: Weigh 4.25g of hydrogen-type mordenite molecular sieve (HM) (silicon-to-aluminum ratio of 15) and add it to the mixed solution. Stir at room temperature for 30 minutes at a speed of 500 r / min. Then transfer it to a high-pressure hydrothermal reactor, add nitrogen gas at 2 MPa, and react at 120℃ for 4 hours.

[0094] Step 3: Remove the product at room temperature, filter and wash with water, and dry at 100℃ for 12 hours; calcine at 550℃ for 5 hours. A modified mordenite molecular sieve catalyst with 5wt% Mg and 10wt% Ce (based on the total weight of the catalyst) is obtained, denoted as 5Mg-10Ce / HM.

[0095] (2) Application of catalysts

[0096] The prepared 5Mg-10Ce / HM catalyst was ground, compressed, and shaped to 40-60 mesh. 3g of the shaped catalyst was added to a 300mL reactor, followed by 50g of 2-isopropylnaphthalene for the preparation of diisopropylnaphthalene. Nitrogen gas was introduced at 1MPa and then released to purge air. The temperature was programmed to rise to 150℃ at a rate of 10℃ / min. Then, 24.57g of propylene gas (molar ratio of 2-isopropylnaphthalene:C3H8 = 1:2) was introduced. Timing was started at 180℃, and the reaction was carried out for 5 hours. Gas chromatography analysis was performed on samples. The conversion rate of 2-isopropylnaphthalene was 99.2%, and the selectivity for diisopropylnaphthalene was 78.5%.

[0097] Example 4

[0098] (1) Catalyst preparation method

[0099] Step 1: Weigh 5.27g of precursor Mg(NO3)2·6H2O, 1.55g of Ce(NO3)3·6H2O and 1.16g of ethylenediamine (the molar ratio of Mg to Ce is 5.8, and the ratio of ethylenediamine to the total amount of Mg and Ce is 0.8) and dissolve them in 20mL of deionized water. Stir the mixed solution magnetically at room temperature for 10min at a speed of 500r / min to form a mixed solution.

[0100] Step 2: Weigh 4.00g of hydrogen-type mordenite molecular sieve (HM) (silicon-to-aluminum ratio of 15) and add it to the mixed solution. Stir at room temperature for 30 minutes at a speed of 500 r / min. Then transfer it to a high-pressure hydrothermal reactor, add nitrogen gas at 2 MPa, and react at 120℃ for 4 hours.

[0101] Step 3: Remove the product at room temperature, filter and wash with water, and dry at 100℃ for 12 hours; calcine at 550℃ for 5 hours. A modified mordenite molecular sieve catalyst with 10wt% Mg and 10wt% Ce (based on the total weight of the catalyst) is obtained, denoted as 10Mg-10Ce / HM.

[0102] (2) Application of catalysts

[0103] The prepared 10Mg-10Ce / HM catalyst was ground, compressed, and shaped to 40-60 mesh. 3g of the shaped catalyst was added to a 300mL reactor, followed by 50g of 2-isopropylnaphthalene for the preparation of diisopropylnaphthalene. Nitrogen gas was introduced at 1MPa and then released to purge air. The temperature was programmed to rise to 150℃ at a rate of 10℃ / min. Then, 24.57g of propylene gas (molar ratio of 2-isopropylnaphthalene:C3H8 = 1:2) was introduced. Timing was started at 180℃, and the reaction was carried out for 5 hours. Gas chromatography analysis was performed on samples. The conversion rate of 2-isopropylnaphthalene was 95.2%, and the selectivity of diisopropylnaphthalene was 71.4%.

[0104] Example 5

[0105] This embodiment is basically the same as Example 1, except that in the catalyst preparation method, a modified mordenite molecular sieve catalyst of 10wt% Mg and 5wt% Ce (based on the total weight of the catalyst) was prepared, denoted as 10Mg-5Ce / HM. The conversion rate of 2-isopropylnaphthalene was 97.3%, and the selectivity of diisopropylnaphthalene was 75.1%.

[0106] Example 6

[0107] This embodiment is basically the same as Example 1, except that the molar ratio of ethylenediamine to the total amount of Mg and Ce in the catalyst preparation method is 1. The conversion rate of 2-isopropylnaphthalene is 98.8%, and the selectivity of diisopropylnaphthalene is 77.8%.

[0108] Example 7

[0109] This embodiment is basically the same as Example 3, except that ethylenediamine is used instead of urea in the catalyst preparation method. The conversion rate of 2-isopropylnaphthalene is 95.5%, and the selectivity of diisopropylnaphthalene is 77.1%.

[0110] Comparative Example 1

[0111] Weigh 4.00g of unmodified mordenite molecular sieve (silicon-to-aluminum ratio of 15), grind, press, and shape to 40-60 mesh.

[0112] 3g of the pre-formed catalyst was added to a 300mL reactor, followed by 50g of 2-isopropylnaphthalene for the preparation of diisopropylnaphthalene. Nitrogen gas was introduced at 1MPa and then released to purge air. The temperature was programmed to rise to 150℃ at a rate of 10℃ / min. Then, 24.57g of propylene gas (molar ratio of 2-isopropylnaphthalene:C3H8 = 1:2) was introduced. Timing was started at 180℃, and the reaction was carried out for 5 hours. Gas chromatography analysis was then performed on a sample. The conversion rate of 2-isopropylnaphthalene was 60.1%, and the selectivity of diisopropylnaphthalene was 70.8%.

[0113] Comparative Example 2

[0114] Step 1: Weigh 1.05g of precursor Mg(NO3)2·6H2O and 0.20g of ethylenediamine (the molar ratio of ethylenediamine to Mg is 0.8) and dissolve them in 20mL of deionized water. Stir the mixed solution magnetically for 10min at room temperature at a speed of 500r / min to form a mixed solution.

[0115] Step 2: Weigh 4.90g of hydrogen-type mordenite molecular sieve (HM) (silicon-to-aluminum ratio of 15) and add it to the mixed solution. Stir at room temperature for 30 minutes at a speed of 500 r / min. Then transfer it to a high-pressure hydrothermal reactor, add nitrogen gas at 2 MPa, and react at 120℃ for 4 hours.

[0116] Step 3: Remove the product at room temperature, filter and wash with water, and dry at 100℃ for 12 hours; calcine at 550℃ for 5 hours. A 2wt% Mg (based on the total weight of the catalyst) modified mordenite molecular sieve catalyst, denoted as 2Mg / HM, is obtained.

[0117] (2) Application of catalysts

[0118] The prepared 2Mg / HM catalyst was ground, compressed, and shaped to 40-60 mesh. 3g of the shaped catalyst was added to a 300mL reactor, followed by 50g of 2-isopropylnaphthalene for the preparation of diisopropylnaphthalene. Nitrogen gas was introduced at 1MPa and then released to purge air. The temperature was programmed to rise to 150℃ at a rate of 10℃ / min. Then, 24.57g of propylene gas (molar ratio of 2-isopropylnaphthalene:C3H8 = 1:2) was introduced. Timing was started at 180℃, and the reaction was carried out for 5 hours. Gas chromatography analysis was performed on samples. The conversion rate of 2-isopropylnaphthalene was 85.8%, and the selectivity for diisopropylnaphthalene was 72.3%.

[0119] Comparative Example 3

[0120] (1) Catalyst preparation method

[0121] Step 1: Weigh 0.31g of precursor Ce(NO3)3·6H2O and 0.03g of ethylenediamine (the molar ratio of ethylenediamine to Ce is 0.8) and dissolve them in 20mL of deionized water. Stir the mixture magnetically at room temperature for 10min at a speed of 500r / min to form a mixed solution.

[0122] Step 2: Weigh 4.90g of hydrogen-type mordenite molecular sieve (HM) (silicon-to-aluminum ratio of 15) and add it to the mixed solution. Stir at room temperature for 30 minutes at a speed of 500 r / min. Then transfer it to a high-pressure hydrothermal reactor, add nitrogen gas at 2 MPa, and react at 120℃ for 4 hours.

[0123] Step 3: Remove the product at room temperature, filter and wash with water, and dry at 100℃ for 12 hours; calcine at 550℃ for 5 hours. A 2wt% Ce (based on the total weight of the catalyst) modified mordenite molecular sieve catalyst, denoted as 2Ce / HM, is obtained.

[0124] (2) Application of catalysts

[0125] The prepared 2Ce / HM catalyst was ground, compressed, and shaped to 40-60 mesh. 3g of the shaped catalyst was added to a 300mL reactor, followed by 50g of 2-isopropylnaphthalene for the preparation of diisopropylnaphthalene. Nitrogen gas was introduced at 1MPa and then released to purge air. The temperature was programmed to rise to 150℃ at a rate of 10℃ / min. Then, 24.57g of propylene gas (molar ratio of 2-isopropylnaphthalene:C3H8 = 1:2) was introduced. Timing was started at 180℃, and the reaction was carried out for 5 hours. Gas chromatography analysis was then performed on samples. The conversion rate of 2-isopropylnaphthalene was 86.5%, and the selectivity for diisopropylnaphthalene was 72.1%.

[0126] Comparative Example 4

[0127] This comparative example is basically the same as Example 1, except that in the catalyst preparation method, ethylenediamine is not added in step 1, the conversion rate of 2-isopropylnaphthalene is 90.1%, and the selectivity of diisopropylnaphthalene is 70.2%.

[0128] Comparative Example 5

[0129] This comparative example is basically the same as Example 3, except that the mordenite molecular sieve is replaced with USY-8. The conversion rate of 2-isopropylnaphthalene is 30.3%, and the selectivity of diisopropylnaphthalene is 71.4%.

[0130] Comparative Example 6

[0131] This comparative example is basically the same as Example 1, except that in the preparation method of the catalyst, Ce(NO3)3·6H2O is replaced with Ni(NO3)2·6H2O to prepare a 1wt% Mg and 1wt% Ni (based on the total weight of the catalyst) modified mordenite molecular sieve catalyst, denoted as 1Mg-1Ni / HM.

[0132] The conversion rate of 2-isopropylnaphthalene was 65.4%, and the selectivity of diisopropylnaphthalene was 71.2%.

[0133] 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 typical embodiments, but it should be understood that the words 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 with the same function.

Claims

1. A method for preparing a molecular sieve catalyst, characterized in that, Includes the following steps: Step 1: Obtain a mixture comprising a Mg-containing precursor, a Ce-containing precursor, a dispersant, and water; Step 2: Mix the mixture obtained in Step 1 with mordenite molecular sieve and carry out a hydrothermal reaction under pressure to obtain the molecular sieve catalyst.

2. The preparation method according to claim 1, characterized in that, In step 1, the dispersant includes at least one of ethylenediamine and urea; And / or, in step 1, the molar ratio of the amount of the dispersant to the total amount of the Mg-containing precursor (calculated as Mg) and the Ce-containing precursor (calculated as Ce) is 0.5-1.

3. The preparation method according to any one of claims 1-2, characterized in that, In step 2, the reaction pressure is 1-3 MPa. And / or, in step 2, the reaction temperature is 100-150℃.

4. The preparation method according to any one of claims 1-3, characterized in that, The total amount of Mg-containing precursors (calculated as Mg) and Ce-containing precursors (calculated as Ce) to the mass ratio of the mordenite molecular sieve is (2-20):(80-98), preferably (5-15):(85-95), and more preferably (10-15):(85-90).

5. The preparation method according to any one of claims 1-4, characterized in that, The mass ratio of the Mg-containing precursor (calculated as Mg) to the mordenite molecular sieve is (1-10):(90-99), preferably (5-10):(90-95); And / or, the mass ratio of the Ce-containing precursor to the mordenite molecular sieve, calculated as Ce, is (1-10):(90-99), preferably (5-10):(90-95).

6. The preparation method according to any one of claims 1-5, characterized in that, In step 1, the Mg-containing precursor includes at least one of Mg nitrate, acetate, halide, sulfate, and acetate. And / or, in step 1, the Ce-containing precursor includes at least one of Ce nitrate, acetate, halide, sulfate, and acetate. And / or, in step 2, the mordenite molecular sieve is a hydrogen-type mordenite molecular sieve, preferably, the silica-alumina ratio of the mordenite molecular sieve is 10-30.

7. A molecular sieve catalyst prepared by any one of claims 1-6, Preferably, the total mass percentage of Mg and Ce, based on the total weight of the catalyst, is 2 wt%-20 wt%, more preferably 5 wt%-15 wt%, and more preferably 10 wt%-15 wt%. Preferably, The mass percentage of Mg, based on the total weight of the catalyst, is 1 wt%-10 wt%, preferably 5 wt%-10 wt%. And / or, based on the total weight of the catalyst, the mass percentage of Ce is 1wt%-10wt%, preferably 5wt%-10wt%.

8. The application of the molecular sieve catalyst according to claim 7 in the preparation method of diisopropylnaphthalene.

9. A method for preparing diisopropylnaphthalene, characterized in that, The method includes the following steps: obtaining a mixture comprising propylene and monoisopropylnaphthalene, reacting it in the presence of the molecular sieve catalyst as described in claim 7 to obtain diisopropylnaphthalene.

10. The method for preparing diisopropylnaphthalene according to claim 9, characterized in that, The reaction temperature is 150-300℃; And / or, the reaction pressure is 1.0-3.5 MPa; And / or, the space velocity of the reaction is 1000-12000 mL / h / g; And / or, the molar ratio of monoisopropylnaphthalene to propylene is 1:(1.5-2.0); And / or, the amount of the molecular sieve catalyst is 0.5-10 wt% of the mass of monoisopropylnaphthalene.