A core-shell structure molecular sieve catalyst, a preparation method and application thereof

Abstract

The application relates to the technical field of molecular sieves, and discloses a core-shell structure molecular sieve catalyst, a preparation method and application thereof. A core-shell structure HMOR@AlPO4-11 composite molecular sieve catalyst takes HMOR molecular sieve as a core and AlPO4-11 molecular sieve as a shell; the preparation method comprises the following steps: mixing a template agent R, a silicon source, an aluminum source, an alkali source and water, and crystallizing to obtain MOR molecular sieve; mixing a template agent Q, an aluminum source, a phosphorus source and water, and aging to obtain AlPO4-11 molecular sieve precursor; uniformly mixing the MOR molecular sieve after being treated by a cationic polymer with the AlPO4-11 molecular sieve precursor, adding water and / or a template agent, crystallizing, roasting, performing proton exchange, and roasting again to obtain the HMOR@AlPO4-11 composite molecular sieve catalyst. Through the technical scheme, the problems of poor selectivity and low catalytic efficiency of the molecular sieve catalyst in the prior art are solved.

Description

Technical Field

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

[0002] Molecular sieves possess ion exchange properties, uniform molecular size and pore size, acid catalytic activity, and good thermal and hydrothermal stability. They can be used to prepare catalysts with high activity and selectivity for many reactions; these are called molecular sieve catalysts, also known as zeolite molecular sieve catalysts. These catalysts use molecular sieves as the active or main active component and are themselves non-toxic and harmless. The application of molecular sieve catalysts in synthesis can significantly improve production efficiency, reduce raw material consumption, lower equipment investment costs, and increase product yield and quality. Furthermore, spent molecular sieve catalysts are environmentally friendly and do not cause pollution.

[0003] In the field of organic synthesis, such as the continuous preparation of 2,6-diisopropylnaphthalene from naphthalene, molecular sieve catalysts are required. However, existing molecular sieve catalysts have poor selectivity, resulting in low product purity and low yield. Therefore, developing a molecular sieve catalyst with good selectivity and high catalytic efficiency is a technical challenge that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0004] This invention proposes a core-shell structured molecular sieve catalyst, its preparation method, and its application, which solves the problems of poor selectivity and low catalytic efficiency of molecular sieve catalysts in related technologies.

[0005] The technical solution of the present invention is as follows: A core-shell structured molecular sieve catalyst, wherein the core-shell structured molecular sieve catalyst is an HMOR@AlPO4-11 composite molecular sieve catalyst, with HMOR molecular sieve as the core and AlPO4-11 molecular sieve as the shell.

[0006] As a further technical solution, the molar ratio of SiO2 / Al2O3 in the HMOR molecular sieve is 50~100:1.

[0007] This invention also proposes a method for preparing a core-shell structured molecular sieve catalyst, comprising the following steps: S1. Mix template agent R, silicon source, aluminum source, alkali source and water, and crystallize to obtain MOR molecular sieve; S2. Mix template agent Q, aluminum source, phosphorus source and water, and age to obtain AlPO4-11 molecular sieve precursor; S3. After treating the MOR molecular sieve with a cationic polymer, mix it evenly with the AlPO4-11 molecular sieve precursor, add water and / or template agent Q, and crystallize to obtain MOR@AlPO4-11 composite molecular sieve. S4. The MOR@AlPO4-11 composite molecular sieve is calcined, proton exchanged, and then calcined again to obtain the HMOR@AlPO4-11 composite molecular sieve catalyst.

[0008] As a further technical solution, the amounts of template agent R, silicon source, aluminum source, alkali source and water in S1 are calculated based on the molar ratio of template agent R:SiO2:Al2O3:M2O:H2O of 0.15~0.50:1:0.01~0.03:0.10~0.30:20.00~30.00; The crystallization temperature in S1 is 150~200℃, and the crystallization time is 24~120h.

[0009] As a further technical solution, the amounts of template agent Q, aluminum source, phosphorus source and water in S2 are calculated based on a molar ratio of template agent Q:Al2O3:P2O5:H2O of 1.50~3.00:1.00:1.00:30.00~50.00; The aging temperature in S2 is 80~120℃, and the aging time is 12~24h.

[0010] As a further technical solution, the crystallization temperature in S3 is 175~200℃, and the crystallization time is 24~120h.

[0011] As a further technical solution, the roasting temperature in S4 is independently 500~600℃ and the roasting time is independently 3~6h.

[0012] As a further technical solution, the proton exchange temperature in S4 is 60~80℃ and the time is 6~12h.

[0013] As a further technical solution, the silicon source includes one or more of silica sol, silica fume, and tetraethyl orthosilicate; And / or, the aluminum source in S1 and the aluminum source in S2 each independently include one or more of aluminum sulfate, sodium aluminate, and boehmite; And / or, the alkali source includes one or both of sodium hydroxide and potassium hydroxide; And / or, the phosphorus source includes phosphoric acid; And / or, the template agent R comprises one or more of tetraethylammonium hydroxide, tetraethylammonium bromide, tetrapropylammonium hydroxide, and tetrapropylammonium bromide; And / or, the template agent Q includes one or more of diethylamine, di-n-propylamine, and diisopropylamine; And / or, the cationic polymer includes one or more of polyethyleneamine, polyacrylamide, and polydiallyldimethylammonium chloride.

[0014] As a further technical solution, the proton exchange in S4 specifically involves: performing proton exchange on the calcined MOR@AlPO4-11 composite molecular sieve in a weakly acidic solution.

[0015] As a further technical solution, the weakly acidic solution is one or more of ammonium nitrate solution, ammonium chloride solution, and dilute hydrochloric acid solution.

[0016] As a further technical solution, the concentration of the weakly acidic solution is 0.2~1 mol / L.

[0017] As a further technical solution, the mass-to-volume ratio of the calcined MOR@AlPO4-11 composite molecular sieve to the weakly acidic solution is 1g:5~10mL.

[0018] As a further technical solution, after proton exchange, centrifugation is performed to collect the solid, which is then washed with water and dried.

[0019] As a further technical solution, the drying temperature is 100~120℃.

[0020] This invention also proposes the application of the core-shell structured molecular sieve catalyst described above or the HMOR@AlPO4-11 composite molecular sieve catalyst prepared by the aforementioned preparation method in the preparation of 2,6-diisopropylnaphthalene.

[0021] The working principle and beneficial effects of this invention are as follows: 1. This invention provides a core-shell structured HMOR@AlPO4-11 composite molecular sieve catalyst, which exhibits good selectivity and high catalytic efficiency in the preparation of 2,6-diisopropylnaphthalene, and can synthesize high-quality 2,6-diisopropylnaphthalene.

[0022] 2. This invention provides a method for preparing a core-shell structured HMOR@AlPO4-11 composite molecular sieve catalyst. By optimizing each reaction stage and limiting the amounts of template agent R, silicon source, aluminum source, alkali source, and water to a molar ratio of template agent R:SiO2:Al2O3:M2O:H2O of 0.15~0.50:1:0.01~0.03:0.10~0.30:20.00~30.00, and the amounts of template agent Q, aluminum source, phosphorus source, and water to a molar ratio of template agent Q:Al2O3:P2O5:H2O of 1.50~3.00:1.00:1.00:30.00~50.00, the yield and purity of the synthesized 2,6-diisopropylnaphthalene are further improved. Detailed Implementation

[0023] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0024] The parameters of the raw materials in the following examples and comparative examples are as follows: The mass concentration of SiO2 in silica sol is 25%~40%; The mass content of SiO2 in precipitated silica is >99%; The Al2O3 content in boehmite is 28%~35% by mass; Polyvinylamine has a purity >98% and a molecular weight M. W The figure is 110,000.

[0025] The polyacrylamide is a cationic polyacrylamide, with an effective substance content of 94 wt% and a weight-average molecular weight of 8 million. The solid content of polydiallyl dimethyl ammonium chloride is >40wt%.

[0026] Example 1 S1. Tetraethylammonium hydroxide, silica sol, aluminum sulfate, sodium hydroxide and deionized water were mixed to prepare a gel mixture with a molar ratio of tetraethylammonium hydroxide:SiO2:Al2O3:Na2O:H2O of 0.35:1:0.02:0.2:25. The mixture was placed in a polytetrafluoroethylene-lined stainless steel synthesis autoclave and hydrothermally crystallized at 180°C for 48 hours. After washing with deionized water and drying, MOR molecular sieve was obtained. S2. Diethylamine, sodium aluminate, phosphoric acid and deionized water were mixed to prepare a gel mixture with a molar ratio of diethylamine:Al2O3:P2O5:H2O of 2.3:1:1:40. The mixture was placed in a polytetrafluoroethylene-lined stainless steel synthesis vessel and aged at 100°C for 20 hours under hydrothermal conditions to obtain the AlPO4-11 molecular sieve precursor. S3. The MOR molecular sieve obtained in S1 was placed in a 10wt% polyethyleneamine aqueous solution and treated at room temperature for 18h. After drying, it was mixed with the AlPO4-11 molecular sieve precursor obtained in S2 and stirred evenly. After sonication for 2h, it was dried and ground under stirring to obtain dry adhesive powder. It was placed on a support inside a stainless steel reactor, and 30mL of deionized water was added to the bottom of the reactor to ensure that the liquid surface did not contact the dry adhesive powder. It was crystallized at 190℃ for 48h and dried to obtain a core-shell MOR@AlPO4-11 composite molecular sieve. S4. After calcining the core-shell MOR@AlPO4-11 composite molecular sieve obtained in S3 in air at 550℃ for 4.5h to remove the template agent, it was subjected to proton exchange in 0.5mol / L dilute hydrochloric acid aqueous solution at 70℃ for 10h at a solid-liquid ratio of 1g:10mL. The solid was collected by centrifugation, washed with deionized water, dried in air at 110℃, and calcined in air at 550℃ for 4.5h. The proton exchange-centrifugation-washing-drying-calcination steps were repeated once more to obtain the hydrogen-form core-shell HMOR@AlPO4-11 composite molecular sieve catalyst.

[0027] Example 2 S1. Tetrapropylammonium hydroxide, tetraethyl orthosilicate, boehmite, potassium hydroxide, and deionized water were mixed to prepare a gel mixture with a molar ratio of tetraethylammonium hydroxide:SiO2:Al2O3:K2O:H2O of 0.15:1:0.01:0.1:20. The mixture was placed in a polytetrafluoroethylene-lined stainless steel synthesis autoclave and hydrothermally crystallized at 150°C for 120 hours. After washing with deionized water and drying, MOR molecular sieve was obtained. S2. Di-n-propylamine, aluminum sulfate, phosphoric acid and deionized water were mixed to prepare a gel mixture with a molar ratio of diethylamine:Al2O3:P2O5:H2O of 1.5:1:1:30. The mixture was placed in a polytetrafluoroethylene-lined stainless steel synthesis vessel and aged at 80°C for 24 hours to obtain the AlPO4-11 molecular sieve precursor. S3. The MOR molecular sieve obtained in S1 was placed in a 10wt% polyacrylamide aqueous solution and treated at room temperature for 12h. After drying, it was mixed with the AlPO4-11 molecular sieve precursor obtained in S2 and stirred evenly. After sonication for 1h, it was dried and ground under stirring to obtain dry adhesive powder. It was placed on a support inside a stainless steel reactor, and 10mL of di-n-propylamine was added to the bottom of the reactor to ensure that the liquid surface did not contact the dry adhesive powder. It was crystallized at 175℃ for 120h and dried to obtain a core-shell MOR@AlPO4-11 composite molecular sieve. S4. After calcining the core-shell MOR@AlPO4-11 composite molecular sieve obtained in S3 in air at 500℃ for 6h to remove the template agent, it was subjected to proton exchange in 0.2mol / L dilute hydrochloric acid aqueous solution at 60℃ for 12h at a solid-liquid ratio of 1g:5mL. The solid was collected by centrifugation, washed with deionized water, dried in air at 100℃, and calcined in air at 500℃ for 6h. The proton exchange-centrifugation-washing-drying-calcination steps were repeated twice to obtain the hydrogen-form core-shell HMOR@AlPO4-11 composite molecular sieve catalyst.

[0028] Example 3 S1. Tetraethylammonium bromide, silica, sodium aluminate, sodium hydroxide, and deionized water were mixed to prepare a gel mixture with a molar ratio of tetraethylammonium hydroxide:SiO2:Al2O3:Na2O:H2O of 0.5:1:0.03:0.3:30. The mixture was placed in a polytetrafluoroethylene-lined stainless steel synthesis autoclave and hydrothermally crystallized at 200°C for 24 hours. After washing with deionized water and drying, MOR molecular sieve was obtained. S2. Diisopropylamine, boehmite, phosphoric acid and deionized water were mixed to prepare a gel mixture with a molar ratio of diethylamine:Al2O3:P2O5:H2O of 3:1:1:50. The mixture was placed in a polytetrafluoroethylene-lined stainless steel synthesis vessel and aged at 120℃ for 12 hours under hydrothermal conditions to obtain the AlPO4-11 molecular sieve precursor. S3. The MOR molecular sieve obtained in S1 was placed in a 10wt% polydiallyldimethylammonium chloride aqueous solution and treated at room temperature for 24h. After drying, it was mixed with the AlPO4-11 molecular sieve precursor obtained in S2 and stirred evenly. After sonication for 3h, it was dried and ground under stirring to obtain dry adhesive powder. The powder was placed on a support inside a stainless steel reactor, and 50mL of diisopropylamine was added to the bottom of the reactor to ensure that the liquid surface did not contact the dry adhesive powder. The powder was crystallized at 200℃ for 24h and then dried to obtain a core-shell MOR@AlPO4-11 composite molecular sieve. S4. After calcining the core-shell MOR@AlPO4-11 composite molecular sieve obtained in S3 in air at 600℃ for 3h to remove the template agent, it was subjected to proton exchange in 1mol / L dilute hydrochloric acid aqueous solution at 80℃ for 6h at a solid-liquid ratio of 1g:8mL. The solid was collected by centrifugation, washed with deionized water, dried in air at 120℃, and calcined in air at 500℃ for 6h. The proton exchange-centrifugation-washing-drying-calcination steps were repeated twice to obtain the hydrogen-form core-shell HMOR@AlPO4-11 composite molecular sieve catalyst.

[0029] Example 4 The only difference from Example 1 is: S2. Diethylamine, sodium aluminate, phosphoric acid and deionized water were mixed to prepare a gel mixture with a molar ratio of diethylamine:Al2O3:P2O5:H2O of 1:1:1:40. The mixture was placed in a polytetrafluoroethylene-lined stainless steel synthesis vessel and aged at 100°C for 20 hours under hydrothermal conditions to obtain the AlPO4-11 molecular sieve precursor.

[0030] Example 5 The only difference from Example 1 is: S2. Diethylamine, sodium aluminate, phosphoric acid and deionized water were mixed to prepare a gel mixture with a molar ratio of diethylamine:Al2O3:P2O5:H2O of 4:1:1:40. The mixture was placed in a polytetrafluoroethylene-lined stainless steel synthesis vessel and aged at 100°C for 20 hours under hydrothermal conditions to obtain the AlPO4-11 molecular sieve precursor.

[0031] Example 6 S1. Tetraethylammonium hydroxide, silica sol, aluminum sulfate, sodium hydroxide and deionized water were mixed to prepare a gel mixture with a molar ratio of tetraethylammonium hydroxide:SiO2:Al2O3:Na2O:H2O of 0.35:1:0.02:0.2:25. The mixture was placed in a polytetrafluoroethylene-lined stainless steel synthesis autoclave and hydrothermally crystallized at 180°C for 48 hours. After washing with deionized water and drying, MOR molecular sieve was obtained. S2. Mix diethylamine, sodium aluminate, phosphoric acid and deionized water to prepare a gel mixture with a molar ratio of diethylamine:Al2O3:P2O5:H2O of 2.3:1:1:40; S3. The MOR molecular sieve obtained in S1 was placed in a 10wt% polyvinylamine aqueous solution and treated at room temperature for 18 hours. After drying, it was mixed and stirred evenly with the gel mixture obtained in S2. After sonication for 2 hours, it was aged at 120℃ under hydrothermal conditions for 12 hours. It was then dried and ground under stirring to obtain dry gel powder. The dry gel powder was placed on a support inside a stainless steel reactor, and 30mL of deionized water was added to the bottom of the reactor to ensure that the liquid surface did not contact the dry gel powder. It was crystallized at 190℃ for 48 hours and then dried to obtain a core-shell MOR@AlPO4-11 composite molecular sieve. S4. After calcining the core-shell MOR@AlPO4-11 composite molecular sieve obtained in S3 in air at 550℃ for 4.5h to remove the template agent, it was subjected to proton exchange in 0.5mol / L ammonium nitrate aqueous solution at 70℃ for 10h at a solid-liquid ratio of 1g:10mL. The solid was collected by centrifugation, washed with deionized water, dried in air at 110℃, and calcined in air at 550℃ for 4.5h. The proton exchange-centrifugation-washing-drying-calcination steps were repeated once more to obtain the hydrogen-form core-shell HMOR@AlPO4-11 composite molecular sieve catalyst.

[0032] Example 7 The only difference from Example 1 is: S1. Tetraethylammonium hydroxide, silica sol, aluminum sulfate, sodium hydroxide and deionized water were mixed to prepare a gel mixture with a molar ratio of tetraethylammonium hydroxide:SiO2:Al2O3:Na2O:H2O of 0.35:1:0.02:0.05:25. The mixture was placed in a polytetrafluoroethylene-lined stainless steel synthesis vessel and hydrothermally crystallized at 180°C for 48 hours. After washing with deionized water and drying, MOR molecular sieve was obtained.

[0033] Example 8 The only difference from Example 1 is: S1. Tetraethylammonium hydroxide, silica sol, aluminum sulfate, sodium hydroxide and deionized water were mixed to prepare a gel mixture with a molar ratio of tetraethylammonium hydroxide:SiO2:Al2O3:Na2O:H2O of 0.35:1:0.02:0.4:25. The mixture was placed in a polytetrafluoroethylene-lined stainless steel synthesis vessel and hydrothermally crystallized at 180℃ for 48 hours. After washing with deionized water and drying, MOR molecular sieve was obtained.

[0034] Example 9 The only difference from Example 1 is that the dilute hydrochloric acid aqueous solution in S4 is replaced with an ammonium nitrate aqueous solution.

[0035] Example 10 The only difference from Example 1 is that the dilute hydrochloric acid aqueous solution in S4 is replaced with an ammonium chloride aqueous solution.

[0036] Example 11 S1. Tetraethylammonium hydroxide, silica sol, aluminum sulfate, sodium hydroxide and deionized water were mixed to prepare a gel mixture with a molar ratio of tetraethylammonium hydroxide:SiO2:Al2O3:Na2O:H2O of 0.35:1:0.02:0.2:25. The mixture was placed in a polytetrafluoroethylene-lined stainless steel synthesis autoclave and hydrothermally crystallized at 180°C for 48 hours. After washing with deionized water and drying, MOR molecular sieve was obtained. S2. After calcining the MOR molecular sieve obtained in S1 in air at 550℃ for 4.5h to remove the template agent, it is then subjected to proton exchange in 0.5mol / L dilute hydrochloric acid aqueous solution at 70℃ for 10h at a solid-liquid ratio of 1g:10mL. The solid is collected by centrifugation, washed with deionized water, dried in air at 110℃, and calcined in air at 550℃ for 4.5h. The proton exchange-centrifugation-washing-drying-calcination steps are repeated once more to obtain HMOR molecular sieve. S3. Diethylamine, sodium aluminate, phosphoric acid and deionized water were mixed to prepare a gel mixture with a molar ratio of diethylamine:Al2O3:P2O5:H2O of 2.3:1:1:40. The mixture was placed in a polytetrafluoroethylene-lined stainless steel synthesis reactor and aged at 100°C for 20 hours under hydrothermal conditions to obtain the AlPO4-11 molecular sieve precursor. S4. The HMOR molecular sieve obtained in S2 was placed in a 10wt% polyethyleneamine aqueous solution and treated at room temperature for 18h. After drying, it was mixed with the AlPO4-11 molecular sieve precursor obtained in S3 and stirred evenly. After sonication for 2h, it was dried under stirring and ground to obtain dry adhesive powder. It was placed on a support inside a stainless steel reactor, and 30mL of deionized water was added to the bottom of the reactor to ensure that the liquid surface did not contact the dry adhesive powder. It was crystallized at 190℃ for 48h and dried to obtain the hydrogen-form core-shell HMOR@AlPO4-11 composite molecular sieve catalyst.

[0037] Comparative Example 1 The B-AlPO4-5 / HMOR composite molecular sieve catalyst was prepared according to the method in Example 6 of CN 103012037 A.

[0038] Performance testing: The preparation method of HMOR molecular sieve is as follows: S1. Tetraethylammonium hydroxide, silica sol, aluminum sulfate, sodium hydroxide and deionized water were mixed to prepare a gel mixture with a molar ratio of tetraethylammonium hydroxide:SiO2:Al2O3:Na2O:H2O of 0.35:1:0.02:0.2:25. The mixture was placed in a polytetrafluoroethylene-lined stainless steel synthesis autoclave and hydrothermally crystallized at 180°C for 48 hours. After washing with deionized water and drying, MOR molecular sieve was obtained. S2. After calcining the MOR molecular sieve obtained in S1 in air at 550℃ for 4.5h to remove the template agent, it is then subjected to proton exchange in 0.5mol / L dilute hydrochloric acid aqueous solution at 70℃ for 10h at a solid-liquid ratio of 1g:10mL. The solid is collected by centrifugation, washed with deionized water, dried in air at 110℃, and calcined in air at 550℃ for 4.5h. The proton exchange-centrifugation-washing-drying-calcination steps are repeated once more to obtain HMOR molecular sieve.

[0039] The composite molecular sieve catalysts obtained in Examples 1-11 and Comparative Example 1 were used to conduct catalytic organic synthesis experiments. The specific methods are as follows: (1) Using 15g of HMOR molecular sieve as a catalyst, 75g of naphthalene and 25g of 2,7-diisopropylnaphthalene were reacted in reactor I at 200℃ for 2h to obtain monoisopropylnaphthalene; (2) Using 15g of HMOR@AlPO4-11 composite molecular sieve catalyst as catalyst, 55g of propylene and 100g of a mixture of naphthalene and monoisopropylnaphthalene were reacted in reactor II at 240℃ for 4h to obtain diisopropylnaphthalene. (3) Diisopropylnaphthalene was separated into naphthalene and monoisopropylnaphthalene by vacuum distillation at 240℃ and 2kPa. The separated mixture of naphthalene and monoisopropylnaphthalene was recycled into reactor II. The remaining diisopropylnaphthalene was crystallized to obtain 2,7-diisopropylnaphthalene and 2,6-diisopropylnaphthalene. 2,7-diisopropylnaphthalene was recycled into reactor I. The purity and yield of 2,6-diisopropylnaphthalene were tested.

[0040] The purity and yield of 2,6-diisopropylnaphthalene synthesized by the composite molecular sieve catalysts obtained in each example and comparative example are recorded in Table 1.

[0041] Yield (%) = Actual product mass × Purity ÷ Theoretical product mass (based on converted naphthalene) × 100 Table 1. Purity and yield of 2,6-diisopropylnaphthalene

[0042] As shown in Table 1, the core-shell structured HMOR@AlPO4-11 composite molecular sieve catalyst provided by this invention yields 2,6-diisopropylnaphthalene with a purity of over 95.72% and a yield of over 72.66%. In contrast, the 2,6-diisopropylnaphthalene obtained using the B-AlPO4-5 / HMOR composite molecular sieve catalyst has a purity of only 90.86% and a yield of only 50.84%.

[0043] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. The application of a core-shell structured molecular sieve catalyst in the continuous preparation of 2,6-diisopropylnaphthalene from naphthalene, characterized in that, The core-shell structured molecular sieve catalyst is an HMOR@AlPO4-11 composite molecular sieve catalyst, with HMOR molecular sieve as the core and AlPO4-11 molecular sieve as the shell; the preparation method of the core-shell structured molecular sieve catalyst includes the following steps: S1. Mix template agent R, silicon source, aluminum source, alkali source and water, and crystallize to obtain MOR molecular sieve; S2. Mix template agent Q, aluminum source, phosphorus source and water, and age to obtain AlPO4-11 molecular sieve precursor; S3. After the MOR molecular sieve is treated with a cationic polymer, it is mixed evenly with the AlPO4-11 molecular sieve precursor, water and / or template agent Q are added, and crystallization is performed to obtain MOR@AlPO4-11 composite molecular sieve. S4. The MOR@AlPO4-11 composite molecular sieve is calcined, proton exchanged, and then calcined again to obtain the HMOR@AlPO4-11 composite molecular sieve catalyst. The silicon source includes one or more of silica sol, silica fume, and tetraethyl orthosilicate; And / or, the aluminum source in S1 and the aluminum source in S2 each independently include one or more of aluminum sulfate, sodium aluminate, and boehmite; And / or, the alkali source includes one or both of sodium hydroxide and potassium hydroxide; And / or, the phosphorus source includes phosphoric acid; And / or, the template agent R comprises one or more of tetraethylammonium hydroxide, tetraethylammonium bromide, tetrapropylammonium hydroxide, and tetrapropylammonium bromide; And / or, the template agent Q includes one or more of diethylamine, di-n-propylamine, and diisopropylamine; And / or, the cationic polymer includes one or more of polyethyleneamine, polyacrylamide, and polydiallyldimethylammonium chloride.

2. The application of the core-shell molecular sieve catalyst according to claim 1 in the continuous preparation of 2,6-diisopropylnaphthalene from naphthalene, characterized in that, The molar ratio of SiO2 / Al2O3 in the HMOR molecular sieve is 50~100:

1.

3. The application of the core-shell structured molecular sieve catalyst according to claim 1 in the continuous preparation of 2,6-diisopropylnaphthalene from naphthalene, characterized in that, The amounts of template agent R, silicon source, aluminum source, alkali source and water in S1 are calculated based on the molar ratio of template agent R:SiO2:Al2O3:M2O:H2O of 0.15~0.50:1:0.01~0.03:0.10~0.30:20.00~30.00; The crystallization temperature in S1 is 150~200℃, and the crystallization time is 24~120h.

4. The application of the core-shell structured molecular sieve catalyst according to claim 1 in the continuous preparation of 2,6-diisopropylnaphthalene from naphthalene, characterized in that, The amounts of template agent Q, aluminum source, phosphorus source and water in S2 are calculated based on a molar ratio of template agent Q:Al2O3:P2O5:H2O of 1.50~3.00:1.00:1.00:30.00~50.

00. The aging temperature in S2 is 80~120℃, and the aging time is 12~24h.

5. The application of the core-shell structured molecular sieve catalyst according to claim 1 in the continuous preparation of 2,6-diisopropylnaphthalene from naphthalene, characterized in that, The crystallization temperature in S3 is 175~200℃, and the crystallization time is 24~120h.

6. The application of the core-shell molecular sieve catalyst according to claim 1 in the continuous preparation of 2,6-diisopropylnaphthalene from naphthalene, characterized in that, The roasting temperature in S4 is 500~600℃ and the roasting time is 3~6h. The proton exchange temperature in S4 is 60~80℃, and the time is 6~12h.

7. The application of the core-shell molecular sieve catalyst according to claim 1 in the continuous preparation of 2,6-diisopropylnaphthalene from naphthalene, characterized in that, The proton exchange in S4 specifically involves performing proton exchange on the calcined MOR@AlPO4-11 composite molecular sieve in a weakly acidic solution.

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