Composite molecular sieve catalyst as well as preparation method and application thereof

Abstract

The invention discloses a composite molecular sieve catalyst and a preparation method and application thereof. According to the mixed catalyst prepared by the invention, the conversion rate of 1-methylnaphthalene and the selectivity of 2-methylnaphthalene in the process of preparing 2-methylnaphthalene by taking 1-methylnaphthalene as a raw material are improved, and the catalyst can be regenerated and recycled, so that the service life of the catalyst is prolonged.

Description

Technical Field

[0001] The present invention relates to the technical field of preparation of fine chemicals, and in particular to a composite molecular sieve catalyst and a preparation method and application thereof. Background Art

[0002] 2-Methylnaphthalene, also known as β-methylnaphthalene, is an important fine chemical and organic chemical raw material, widely used in industries such as medicine, dyes, photosensitive materials, rubber, plastics, agricultural feed and new polymer materials. 2-Methylnaphthalene is mainly used to produce vitamin K3, hemostatic agents, textile detergents, emulsifiers, wetting agents, and is also the main raw material for producing fine chemical products such as cement water reducers, plant growth regulators, and feed additives. The content of 2-methylnaphthalene in high-temperature coal tar is about 1%. At present, the annual output of 2-methylnaphthalene in my country is less than 100,000 tons. Therefore, using 1-methylnaphthalene as a raw material to prepare 2-methylnaphthalene through isomerization reaction can significantly improve the economic benefits of the enterprise and has important practical significance. However, the preparation of 2-methylnaphthalene using 1-methylnaphthalene as a raw material still has problems of low conversion rate and selectivity, which needs to be studied and improved.

[0003] At present, in the field of chemical synthesis of 2-methylnaphthalene, 1-methylnaphthalene is the most commonly used reaction raw material, and the catalyst is zeolite molecular sieve or modified zeolite molecular sieve. The disadvantages are that the activity of the molecular sieve catalyst is low, and the conversion rate of 1-methylnaphthalene is low; the selectivity of the catalyst is poor, and there are side reactions such as 1-methylnaphthalene disproportionation, dealkylation, and coking. There are many by-products in the product, resulting in a low yield of 2-methylnaphthalene; the catalyst is easily deactivated and has a short life. The above factors affect the economic benefits of the technology of preparing 2-methylnaphthalene by isomerization of 1-methylnaphthalene, and limit the industrialization and promotion of the technology of preparing 2-methylnaphthalene by chemical synthesis of 1-methylnaphthalene. Summary of the invention

[0004] The present invention aims to solve one of the technical problems in the related art at least to a certain extent.

[0005] To this end, embodiments of the present invention provide a composite molecular sieve catalyst and a preparation method and application thereof.

[0006] In the first aspect, the present invention provides a method for preparing a composite molecular sieve catalyst, such as Figure 1 As shown, the following steps are included:

[0007] (1) Naβ and NaY zeolite molecular sieve powders are subjected to multiple ion exchange by stirring the solution under water bath conditions, respectively, and filter cakes are obtained by washing and filtering, and the filter cakes are dried and calcined to obtain Hβ type molecular sieve and HY type molecular sieve respectively;

[0008] (2) modifying the Hβ molecular sieve and the HY molecular sieve by using a rare earth metal salt solution and an alkaline earth metal salt solution respectively by an equal volume impregnation method to obtain a modified Hβ molecular sieve and a modified HY molecular sieve;

[0009] (3) The modified Hβ type, modified HY type molecular sieve, epoxy resin, citric acid and sesbania powder are mixed in a certain proportion to form a mixed material, kneaded and formed, dried, roasted, and then crushed and sieved to obtain a granular mixed catalyst.

[0010] Furthermore, the addition ratio of the solution to the Naβ or NaY zeolite molecular sieve is 15-25 ml / g.

[0011] The addition ratio of the solution to the Naβ zeolite molecular sieve, or the addition ratio of the solution to the NaY zeolite molecular sieve can be 15 ml / g, 18 ml / g, 20 ml / g, 22 ml / g, 25 ml / g or a value within the range of any two values.

[0012] Furthermore, the solution is a salt solution with a mass concentration of 50% to 80% or an acid solution with a mass concentration of 20% to 30%.

[0013] When the solution is a salt solution, its mass concentration can be 50%, 60%, 70%, 80% or a value within a range consisting of any two numerical values; when the solution is an acid solution, its mass concentration can be 20%, 25%, 28%, 30% or a value within a range consisting of any two numerical values.

[0014] Furthermore, the salt solution is an ammonium chloride solution or an ammonium sulfate solution. In some embodiments, the salt solution may also be other suitable types.

[0015] Furthermore, the acid solution is a hydrochloric acid solution or a sulfuric acid solution. In some embodiments, the acid solution may also be other suitable types.

[0016] Furthermore, the temperature of the water bath is 40-60°C.

[0017] The temperature of the water bath can be 40°C, 45°C, 50°C, 55°C, 60°C or a value within a range consisting of any two values. Carrying out ion exchange in a water bath can, on the one hand, increase the exchange rate, and on the other hand, maintain the temperature stability of the ion exchange process.

[0018] Furthermore, in step (1), the number of ion exchanges is 3 to 8 times, and the time for each ion exchange is 1 to 3 hours. After each ion exchange is completed, deionized water is added for washing and filtering, and the next ion exchange is performed until the exchange is completed.

[0019] The number of ion exchanges can be 3 times, 5 times, 7 times, 8 times or a value within a range consisting of any two values, and the time of ion exchange can be 1 h, 2 h, 3 h or a value within a range consisting of any two values.

[0020] Furthermore, in step (1), the drying temperature of the filter cake is 110-150°C, and the drying time is 5-15h. In some embodiments, the drying temperature of the filter cake can be 110°C, 120°C, 130°C, 140°C, 150°C, or a value within a range consisting of any two numerical values, and the drying time can be 5h, 8h, 10h, 12h, 15h, or a value within a range consisting of any two numerical values.

[0021] Furthermore, in step (1), the calcination temperature is 500-650°C, and the calcination time is 4-9h. In some embodiments, the calcination temperature can be 500°C, 550°C, 600°C, 650°C or a value within a range consisting of any two numerical values, and the calcination time is 4h, 6h, 8h, 9h or a value within a range consisting of any two numerical values.

[0022] Further, step (2) comprises:

[0023] (a) preparing rare earth metal salt solutions with different rare earth metal ion contents according to the required amount of water, uniformly dropping them into the Hβ molecular sieve, standing them for impregnation at room temperature, heating and evaporating them, and drying and calcining them to obtain the modified Hβ molecular sieve;

[0024] (b) preparing alkaline earth metal salt solutions with different alkaline earth metal ion contents according to the required amount of water, uniformly adding the solutions to the HY type molecular sieve, allowing the solution to stand at room temperature for impregnation, heating and evaporating the solution, and drying and calcining the solution to obtain the modified HY type molecular sieve.

[0025] Furthermore, in step (a), the mass concentration of the rare earth metal salt solution is 10% to 30%, the rare earth metal salt solution is a cerium chloride solution or a gadolinium chloride solution, the immersion time is 12 to 20 hours, the drying temperature is 120 to 160° C., the drying time is 5 to 15 hours, the calcination temperature is 550 to 700° C., and the calcination time is 3 to 6 hours.

[0026] In some embodiments, the mass concentration of the rare earth metal salt solution is 10%, 15%, 20%, 25%, 30% or a value within a range consisting of any two numerical values, the immersion time is 12h, 14h, 16h, 18h, 20h or a value within a range consisting of any two numerical values, the drying temperature is 120°C, 130°C, 140°C, 150°C, 160°C or a value within a range consisting of any two numerical values, the drying time is 5h, 10h, 12h, 15h or a value within a range consisting of any two numerical values, the calcination temperature is 550°C, 600°C, 650°C, 700°C or a value within a range consisting of any two numerical values, and the calcination time is 3h, 4h, 5h, 6h or a value within a range consisting of any two numerical values.

[0027] Furthermore, in step (b), the mass concentration of the alkaline earth metal salt solution is 10% to 30%, the alkaline earth metal salt solution is a magnesium nitrate solution or a barium nitrate solution, the immersion time is 12 to 30 hours, the drying temperature is 120 to 160° C., the drying time is 5 to 15 hours, the roasting temperature is 550 to 700° C., and the roasting time is 3 to 6 hours.

[0028] In some embodiments, the mass concentration of the alkaline earth metal salt solution is 10%, 15%, 20%, 25%, 30% or a value within a range consisting of any two numerical values, the immersion time is 12h, 14h, 16h, 18h, 20h, 25h, 30h or a value within a range consisting of any two numerical values, the drying temperature is 120°C, 130°C, 140°C, 150°C, 160°C or a value within a range consisting of any two numerical values, the drying time is 5h, 10h, 12h, 15h or a value within a range consisting of any two numerical values, the calcination temperature is 550°C, 600°C, 650°C, 700°C or a value within a range consisting of any two numerical values, and the calcination time is 3h, 4h, 5h, 6h or a value within a range consisting of any two numerical values.

[0029] Furthermore, the mass content of rare earth metals in the modified Hβ molecular sieve is 1% to 2%; the mass content of alkaline earth metals in the modified HY molecular sieve is 1.5% to 2.5%.

[0030] In some embodiments, the mass content of rare earth metals in the modified Hβ molecular sieve is 1%, 1.5%, 2%, or a value within a range consisting of any two numerical values, and the mass content of alkaline earth metals in the modified HY molecular sieve is 1.5%, 2%, 2.5%, or a value within a range consisting of any two numerical values.

[0031] Furthermore, in the mixed material, the mass proportion of the modified Hβ type is 50% to 60%, the mass proportion of the modified HY type molecular sieve is 25% to 35%, and the total mass proportion of epoxy resin, citric acid and sesbania powder is 2% to 10%.

[0032] In some embodiments, the mass proportion of the modified Hβ type in the mixture material is 50%, 55%, 60% or a value within a range consisting of any two numerical values, and the mass proportion of the modified HY type molecular sieve is 25%, 30%, 35% or a value within a range consisting of any two numerical values.

[0033] Furthermore, the particle size of the granular mixed catalyst is 30 to 60 meshes.

[0034] In a second aspect, the present invention proposes a composite molecular sieve catalyst prepared by the method proposed in the first aspect.

[0035] In a third aspect, the present invention proposes the use of the composite molecular sieve catalyst prepared by the method proposed in the first aspect or the composite molecular sieve catalyst proposed in the second aspect in the preparation of 2-methylnaphthalene using 1-methylnaphthalene as raw material.

[0036] Compared with the prior art, the beneficial effects of the present invention are:

[0037] The mixed catalyst prepared by the invention improves the conversion rate of 1-methylnaphthalene and the selectivity of 2-methylnaphthalene in the process of preparing 2-methylnaphthalene from 1-methylnaphthalene as a raw material, and the catalyst can be regenerated and recycled, thereby improving the service life of the catalyst. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] The above and / or additional aspects and advantages of the present invention will become apparent and easily understood from the following description of the embodiments in conjunction with the accompanying drawings, in which:

[0039] Figure 1 The present invention is a flow chart of the preparation method of the composite molecular sieve catalyst. DETAILED DESCRIPTION

[0040] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, and should not be construed as limiting the present invention.

[0041] Unless otherwise specified, the test materials and reagents used in the following examples can be obtained from commercial sources.

[0042] If no specific techniques or conditions are specified in the examples, they can be carried out according to the techniques or conditions described in the literature in the art or according to the product instructions.

[0043] Example 1

[0044] Using 20g Naβ zeolite molecular sieve powder as raw material, ion exchange was carried out 5 times with ammonium sulfate solution with a mass concentration of 60% under stirring conditions in a water bath at 50°C, wherein the addition ratio of ammonium sulfate solution to Naβ zeolite molecular sieve powder was 20ml / g, and deionized water was added for washing and filtering after each ion exchange was completed, and the next ion exchange was carried out until the exchange was completed. After the last ion exchange was completed, the filter cake was washed and filtered to obtain the filter cake, which was dried at 120°C for 10h and calcined at 550°C for 6h to obtain Hβ type molecular sieve.

[0045] A cerium chloride solution with a mass concentration of 15% is prepared according to the required amount of water, and the solution is uniformly added dropwise to the Hβ molecular sieve. The solution is allowed to stand and soak for 16 hours at room temperature, and then heated to dryness. The solution is dried at 140°C for 8 hours, and then calcined at 650°C for 4 hours to obtain a modified Hβ molecular sieve, wherein the cerium content in the modified Hβ molecular sieve is 1.2%.

[0046] Using 20g NaY zeolite molecular sieve powder as raw material, ion exchange was carried out 6 times with ammonium sulfate solution with a mass concentration of 60% under stirring conditions in a water bath at 45°C, wherein the addition ratio of ammonium sulfate solution to Naβ zeolite molecular sieve powder was 15ml / g, and deionized water was added for washing and filtering after each ion exchange was completed, and the next ion exchange was carried out until the exchange was completed. After the last ion exchange was completed, the filter cake was washed and filtered to obtain the filter cake, which was dried at 120°C for 10h and calcined at 550°C for 6h to obtain HY type molecular sieve.

[0047] A barium nitrate solution with a mass concentration of 15% is prepared according to the required amount of water, and is evenly added to the Hβ molecular sieve. After being immersed at room temperature for 20 hours, it is heated to dryness, and after being dried at 140°C for 9 hours, it is calcined at 650°C for 5 hours to obtain a modified HY molecular sieve, wherein the barium content in the modified HY molecular sieve is 1.6%.

[0048] The modified Hβ type, modified HY type molecular sieve, epoxy resin, citric acid and sesbania powder are mixed in a certain proportion to form a mixed material, wherein the mass proportion of the modified Hβ type is 50%, and the mass proportion of the modified HY type molecular sieve is 30%. After the mixed material is kneaded into shape, it is dried at 150°C for 10 hours and calcined at 550°C for 5 hours. After being crushed, it is sieved through a 60-mesh sieve to obtain a granular mixed catalyst.

[0049] Example 2

[0050] Using 20g Naβ zeolite molecular sieve powder as raw material, ion exchange was carried out 5 times with ammonium sulfate solution with a mass concentration of 60% under stirring conditions in a water bath at 50°C, wherein the addition ratio of ammonium sulfate solution to Naβ zeolite molecular sieve powder was 20ml / g, and deionized water was added for washing and filtering after each ion exchange was completed, and the next ion exchange was carried out until the exchange was completed. After the last ion exchange was completed, the filter cake was washed and filtered to obtain the filter cake, which was dried at 120°C for 10h and calcined at 550°C for 6h to obtain Hβ type molecular sieve.

[0051] A cerium chloride solution with a mass concentration of 25% is prepared according to the required amount of water, and the solution is uniformly added dropwise to the Hβ molecular sieve. The solution is allowed to stand and soak for 16 hours at room temperature, and then heated to dryness. After drying at 140°C for 8 hours, the solution is calcined at 650°C for 4 hours to obtain a modified Hβ molecular sieve, wherein the cerium content in the modified Hβ molecular sieve is 1.5%.

[0052] Using 20g NaY zeolite molecular sieve powder as raw material, ion exchange was carried out 6 times with ammonium sulfate solution with a mass concentration of 60% under stirring conditions in a water bath at 45°C, wherein the addition ratio of ammonium sulfate solution to Naβ zeolite molecular sieve powder was 15ml / g, and deionized water was added for washing and filtering after each ion exchange was completed, and the next ion exchange was carried out until the exchange was completed. After the last ion exchange was completed, the filter cake was washed and filtered to obtain the filter cake, which was dried at 120°C for 10h and calcined at 550°C for 6h to obtain HY type molecular sieve.

[0053] A magnesium nitrate solution with a mass concentration of 25% is prepared according to the required amount of water, and the solution is uniformly added to the Hβ molecular sieve. The solution is allowed to stand at room temperature for 20 hours and then heated to dryness. The solution is dried at 140°C for 9 hours and then calcined at 650°C for 5 hours to obtain a modified HY molecular sieve, wherein the magnesium content in the modified HY molecular sieve is 2.0%.

[0054] The modified Hβ type, modified HY type molecular sieve, epoxy resin, citric acid and sesbania powder are mixed in a certain proportion to form a mixed material, wherein the mass proportion of the modified Hβ type is 50%, and the mass proportion of the modified HY type molecular sieve is 30%. After the mixed material is kneaded into shape, it is dried at 150°C for 10 hours and calcined at 550°C for 5 hours. After being crushed, it is sieved through a 60-mesh sieve to obtain a granular mixed catalyst.

[0055] Example 3

[0056] Using 20g Naβ zeolite molecular sieve powder as raw material, ion exchange was carried out 5 times with ammonium sulfate solution with a mass concentration of 60% under stirring conditions in a water bath at 50°C, wherein the addition ratio of ammonium sulfate solution to Naβ zeolite molecular sieve powder was 20ml / g, and deionized water was added for washing and filtering after each ion exchange was completed, and the next ion exchange was carried out until the exchange was completed. After the last ion exchange was completed, the filter cake was washed and filtered to obtain the filter cake, which was dried at 120°C for 10h and calcined at 550°C for 6h to obtain Hβ type molecular sieve.

[0057] A gadolinium chloride solution with a mass concentration of 28% was prepared according to the required amount of water, and the solution was uniformly added dropwise to the Hβ molecular sieve. The solution was allowed to stand at room temperature for 16 hours and then heated to dryness. The solution was dried at 140° C. for 8 hours and then calcined at 650° C. for 4 hours to obtain a modified Hβ molecular sieve, wherein the gadolinium content in the modified Hβ molecular sieve was 1.8%.

[0058] Using 20g NaY zeolite molecular sieve powder as raw material, ion exchange was carried out 6 times with ammonium sulfate solution with a mass concentration of 60% under stirring conditions in a water bath at 45°C, wherein the addition ratio of ammonium sulfate solution to Naβ zeolite molecular sieve powder was 15ml / g, and deionized water was added for washing and filtering after each ion exchange was completed, and the next ion exchange was carried out until the exchange was completed. After the last ion exchange was completed, the filter cake was washed and filtered to obtain the filter cake, which was dried at 120°C for 10h and calcined at 550°C for 6h to obtain HY type molecular sieve.

[0059] A barium nitrate solution with a mass concentration of 30% is prepared according to the required amount of water, and is evenly added to the Hβ molecular sieve. After being immersed at room temperature for 20 hours, it is heated to dryness, and after being dried at 140°C for 9 hours, it is calcined at 650°C for 5 hours to obtain a modified HY molecular sieve, wherein the barium content in the modified HY molecular sieve is 2.4%.

[0060] The modified Hβ type, modified HY type molecular sieve, epoxy resin, citric acid and sesbania powder are mixed in a certain proportion to form a mixed material, wherein the mass proportion of the modified Hβ type is 50%, and the mass proportion of the modified HY type molecular sieve is 30%. After the mixed material is kneaded into shape, it is dried at 150°C for 10 hours and calcined at 550°C for 5 hours. After being crushed, it is sieved through a 60-mesh sieve to obtain a granular mixed catalyst.

[0061] Test Example 1

[0062] 3 g of the granular mixed catalyst prepared in Example 1 and 100 g of 1-methylnaphthalene raw material were added to a kettle reactor to carry out an isomerization reaction. After the reaction materials were added, the reactor was pressurized with nitrogen to a reaction pressure of 5 MPa, and then the reactor was started for stirring and the reactor was heated to a reaction temperature of 280°C and then the reaction was started for 2 hours.

[0063] After the reaction is completed, the solid-liquid mixture in the reactor is discharged from the reactor and added to a centrifuge for centrifugal separation. The centrifuge operating temperature is 50°C, the centrifuge speed is 5000rpm, the centrifugal force is 10000g, and the centrifugal time is 50min. The liquid mixture and the used catalyst are obtained by centrifugal separation.

[0064] A small amount of the liquid mixture is directly analyzed by gas chromatography, and the peak area percentage method is used to calculate the conversion rate of 1-methylnaphthalene and the selectivity of 2-methylnaphthalene. Among them, the conversion rate of 1-methylnaphthalene is the ratio of the amount of 1-methylnaphthalene reacted to the amount of 1-methylnaphthalene added, and the selectivity of 2-methylnaphthalene is the ratio of the amount of 2-methylnaphthalene in the product to the amount of all methylnaphthalene isomers in the product.

[0065] The liquid mixture is added into an intermittent high-efficiency packed distillation tower for distillation. The distillation tower pressure is 6 kPa, the tower top temperature is 180°C, and the tower bottom temperature is 210°C. Unreacted 1-methylnaphthalene and 2-methylnaphthalene product prepared by isomerization are obtained by distillation. The material flowing out of the tower top is the 2-methylnaphthalene product, and the tower bottom is the 1-methylnaphthalene enriched liquid, which can be recycled.

[0066] Test Example 2

[0067] The difference from Experimental Example 1 is that the granular mixed catalyst is prepared by Example 2.

[0068] Test Example 3

[0069] The difference from Experimental Example 1 is that the granular mixed catalyst is prepared by Example 3.

[0070] Test Example 4

[0071] The difference from Test Example 1 is that the granular mixed catalyst is regenerated from the used catalyst of Test Example 1. The regeneration process of the catalyst is as follows: the used catalyst is placed in a tubular furnace and heated at 600°C for 3 hours. During the heating process, air is continuously blown in, and the air volume per hour is 3 to 5 times the volume of the tubular furnace.

[0072] Test Example 5

[0073] The difference from Experimental Example 1 is that the catalyst used is the modified Hβ molecular sieve obtained in the preparation process of Example 1.

[0074] Test Example 6

[0075] The difference from Experimental Example 1 is that the catalyst used is the modified HY molecular sieve obtained in the preparation process of Example 1.

[0076] Test Example 7

[0077] The difference from Experimental Example 1 is that the catalyst used is a zeolite molecular sieve.

[0078] The data of 1-methylnaphthalene conversion and 2-methylnaphthalene selectivity in Experimental Examples 1 to 7 are shown in Table 1 below.

[0079] Table 1:

[0080]

[0081]

[0082] According to Table 1, we can see that:

[0083] In Experimental Examples 1 to 3, the isomerization reaction of 1-methylnaphthalene was carried out using the mixed catalyst prepared by the present invention. The conversion rate of 1-methylnaphthalene and the selectivity of 2-methylnaphthalene were better than those in Experimental Example 7. It can be seen that the mixed catalyst prepared by the present invention has a higher catalytic performance.

[0084] The conversion rate of 1-methylnaphthalene and the selectivity of 2-methylnaphthalene in Test Example 1 are better than those in Test Example 5 and Test Example 6. It can be seen that when the modified Hβ molecular sieve is mixed with the modified HY molecular sieve, the catalytic performance is better than that when used alone. When the modified Hβ molecular sieve is mixed with the modified HY molecular sieve, they can cooperate with each other to achieve better catalytic performance.

[0085] The conversion rate of 1-methylnaphthalene and the selectivity of 2-methylnaphthalene in Test Example 4 are not much different from those in Test Example 1. It can be seen that the mixed catalyst prepared by the present invention can be regenerated and recycled, and its service life is increased.

[0086] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms may be for different embodiments or examples. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, unless they are contradictory.

[0087] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0088] Although the embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the claims and their equivalents.

Claims

1. A method for preparing a composite molecular sieve catalyst, characterized in that: The following steps are involved: (1) Naβ and NaY zeolite molecular sieve powders are subjected to multiple ion exchange by stirring the solution under water bath conditions, respectively, and filter cakes are obtained by washing and filtering, and the filter cakes are dried and calcined to obtain Hβ type molecular sieve and HY type molecular sieve respectively; (2) modifying the Hβ molecular sieve and the HY molecular sieve by using a rare earth metal salt solution and an alkaline earth metal salt solution respectively by an equal volume impregnation method to obtain a modified Hβ molecular sieve and a modified HY molecular sieve; (3) The modified Hβ type, modified HY type molecular sieve, epoxy resin, citric acid and sesbania powder are mixed in a certain proportion to form a mixed material, kneaded and formed, dried, roasted, and then crushed and sieved to obtain a granular mixed catalyst.

2. The method according to claim 1, characterized in that In step (1), the addition ratio of the solution to Naβ or NaY zeolite molecular sieve is 15-25 ml / g; And / or, the solution is a salt solution with a mass concentration of 50% to 80% or an acid solution with a mass concentration of 20% to 30%; And / or, the salt solution is ammonium chloride solution or ammonium sulfate solution; And / or, the acid solution is a hydrochloric acid solution or a sulfuric acid solution; And / or, the temperature of the water bath is 40-60°C.

3. The method according to claim 1, characterized in that In step (1), the number of ion exchanges is 3 to 8 times, and the time for each ion exchange is 1 to 3 hours. After each ion exchange is completed, deionized water is added for washing and filtering, and the next ion exchange is performed until the exchange is completed.

4. The method according to claim 1, characterized in that In step (1), the filter cake is dried at a temperature of 110 to 150° C. and for a drying time of 5 to 15 hours; And / or, in step (1), the calcination temperature is 500-650° C. and the calcination time is 4-9 hours.

5. The method according to claim 1, characterized in that Step (2) comprises: (a) preparing rare earth metal salt solutions with different rare earth metal ion contents according to the required amount of water, uniformly dropping them into the Hβ molecular sieve, standing them for impregnation at room temperature, heating and evaporating them, and drying and calcining them to obtain the modified Hβ molecular sieve; (b) preparing alkaline earth metal salt solutions with different alkaline earth metal ion contents according to the required amount of water, uniformly adding the solutions to the HY type molecular sieve, allowing the solution to stand at room temperature for impregnation, heating and evaporating the solution, and drying and calcining the solution to obtain the modified HY type molecular sieve.

6. The method according to claim 5, characterized in that In step (a), the mass concentration of the rare earth metal salt solution is 10% to 30%, the rare earth metal salt solution is a cerium chloride solution or a gadolinium chloride solution, the immersion time is 12 to 20 hours, the drying temperature is 120 to 160° C., the drying time is 5 to 15 hours, the calcination temperature is 550 to 700° C., and the calcination time is 3 to 6 hours; In step (b), the mass concentration of the alkaline earth metal salt solution is 10% to 30%, the alkaline earth metal salt solution is a magnesium nitrate solution or a barium nitrate solution, the immersion time is 12 to 30 hours, the drying temperature is 120 to 160° C., the drying time is 5 to 15 hours, the roasting temperature is 550 to 700° C., and the roasting time is 3 to 6 hours.

7. The method according to claim 1, characterized in that The mass content of rare earth metals in the modified Hβ molecular sieve is 1% to 2%; the mass content of alkaline earth metals in the modified HY molecular sieve is 1.5% to 2.5%.

8. The method according to claim 1, characterized in that In step (3), the mass proportion of the modified Hβ type in the mixed material is 50% to 60%, the mass proportion of the modified HY type molecular sieve is 25% to 35%, the total mass proportion of epoxy resin, citric acid and sesbania powder is 2% to 10%, and the particle size of the granular mixed catalyst is 30 to 60 mesh.

9. A composite molecular sieve catalyst, characterized in that: The method is prepared by any one of claims 1 to 8.

10. Use of the composite molecular sieve catalyst prepared by the method according to any one of claims 1 to 8 or the composite molecular sieve catalyst according to claim 9 in the preparation of 2-methylnaphthalene using 1-methylnaphthalene as raw material.

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