Molecular sieve crystallization auxiliary agent and preparation method and application thereof

Abstract

The invention discloses a molecular sieve crystallization auxiliary agent and a preparation method and application thereof. A two-dimensional image of a crystal in the molecular sieve crystallization auxiliary agent is rectangular, the length size of the crystal is 5.0-18.0 nm, the width size of the crystal is 2.0-6.0 nm, and the ratio of the length to the width is 1.5-3.5. When the molecular sieve crystallization auxiliary agent is added into a conventional formula for synthesizing a molecular sieve, the crystallization time of the molecular sieve can be obviously shortened, and the grain size of the molecular sieve is reduced.

Description

Technical Field

[0001] The invention belongs to the technical field of catalytic chemistry and chemical engineering, and in particular relates to a molecular sieve crystallization aid and a preparation method and application thereof. Background Art

[0002] In order to shorten the crystallization time of molecular sieves, reduce the grain size, or obtain molecular sieve products with special morphology, specific additives are usually added during the molecular sieve crystallization process to assist the crystallization.

[0003] Patent CN110217804A discloses a ZSM-5 molecular sieve and a preparation method thereof, a hydrogen-type ZSM-5 molecular sieve and its application, and a method for methanol conversion, wherein a spherical ZSM-5 molecular sieve containing a template is added as a seed during the crystallization process of the ZSM-5 molecular sieve, and the obtained molecular sieve significantly improves the selectivity of propylene and butene in the methanol conversion to olefins, and prolongs the life of the catalyst. In this method, seed crystals are added to assist crystallization, but the seed crystals are spherical ZSM-5 molecular sieve powder containing a template, and since the synthesis process of the ZSM-5 molecular sieve powder is long, the production cost of the final product is undoubtedly increased.

[0004] Patent CN114573003A discloses a method for synthesizing SSZ-39 molecular sieves by seed crystal method, in which pre-synthesized SSZ-39 molecular sieve powder is added as a seed crystal to assist crystallization during the synthesis of SSZ-39 molecular sieves, and the obtained SSZ-39 molecular sieve has a cubic shape and uniform particle size. This method also adds SSZ-39 molecular sieve powder with a long synthesis process to assist crystallization, which will also lead to a longer production cycle of the final product and a significant increase in cost.

[0005] Patent CN105645430A discloses a method for rapidly synthesizing Ti-MWW molecular sieve by a seed crystal method. First, seed crystals are added to a reaction gel, and then the reaction gel is sealed in a crystallization kettle. The crystallization kettle is then rotated along a horizontal axis for aging and rotational crystallization. The total time is greater than or equal to 48 hours and less than or equal to 60 hours. This greatly shortens the synthesis time of the Ti-MWW molecular sieve and saves production costs. The seed crystals play a role in assisting crystallization during the crystallization process, effectively shortening the crystallization time. The seed crystals disclosed in this method are Ti-MWW molecular sieve raw powder.

[0006] In summary, it can be seen from the above-mentioned publicly reported literature that adding molecular sieve powder as a seed to assist crystallization in the synthesis of molecular sieves can change the morphology of the molecular sieve or shorten the crystallization time of the molecular sieve. However, the synthesis process of molecular sieve powder is long, and generally requires the steps of batching, gelling, crystallization, solid-liquid separation, drying and calcination. In the actual industrial production process, it will undoubtedly lead to a significant increase in the production cost of the finished molecular sieve, and the production cycle will be lengthened. In the production process, some ammonia nitrogen wastewater containing organic amines will be generated, which is environmentally unfriendly. Summary of the invention

[0007] In view of the above problems existing in the prior art, the present invention provides a molecular sieve crystallization aid and its preparation method and application. The molecular sieve crystallization aid of the present invention can effectively change the crystal morphology of the molecular sieve, improve the catalytic performance, and greatly shorten the crystallization time of the molecular sieve, thereby reducing the production cost.

[0008] The first aspect of the present invention provides a method for preparing a molecular sieve crystallization aid, comprising the following steps:

[0009] (a) contacting a silicon source, an aluminum source, water, an organic substance 1 and an organic substance 2 to obtain a mixture A;

[0010] (b) treating the mixture A to obtain a molecular sieve crystallization aid.

[0011] In the above technical solution, preferably, the silicon source in step (a) is one or more of tetramethyl silicate, tetraethyl silicate, tetrapropyl silicate, tetrabutyl silicate, and tetraphenyl silicate, preferably one or more of tetraethyl silicate, tetrapropyl silicate, and tetraphenyl silicate.

[0012] In the above technical solution, preferably, the aluminum source in step (a) is one or more of aluminum sulfate, aluminum isopropoxide, sodium aluminate, and pseudo-boehmite, preferably one or more of aluminum sulfate and pseudo-boehmite.

[0013] In the above technical scheme, preferably, the organic matter 1 in step (a) is one or more of tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrapropylammonium hydroxide, tetrabutylammonium hydroxide, ethylamine, ethylenediamine, n-butylamine, butylenediamine, hexamethyleneimine, piperidine, piperazine, and dicyclohexylamine, preferably one or more of tetraethylammonium hydroxide, tetrapropylammonium hydroxide, ethylamine, n-butylamine, and hexamethyleneimine.

[0014] In the above technical solution, preferably, the structural formula of the organic matter 2 in step (a) is as shown in Formula I, wherein R1-R6 are each independently selected from methyl, ethyl, propyl or phenyl, at least one of R1-R6 is phenyl, and preferably, there are 4 to 6 phenyl groups in R1-R6;

[0015]

[0016] In the above technical solution, preferably, in step (a), the molar ratio of silicon source, aluminum source, water and organic matter 1 is silicon source: aluminum source: water: organic matter 1 = 1: (0-0.05): (5-30): (0.1-1), the silicon source is calculated as SiO2, and the aluminum source is calculated as Al2O3. The ratio of the mass of organic matter 2 to the total mass of the silicon source, aluminum source, water and organic matter 1 is (0.05-0.2): 1, and the total mass is calculated according to the mass of the actual substance.

[0017] In the above technical solution, preferably, the treatment in step (b) is carried out under stirring, and the treatment conditions are 60-85° C. for 4-24 hours, preferably a closed treatment.

[0018] The second aspect of the present invention provides a molecular sieve crystallization aid prepared by the above preparation method.

[0019] In the above technical solution, the two-dimensional image of the crystals in the molecular sieve crystallization aid is a rectangle, the length dimension of the crystals is 5.0-18.0 nm, the width dimension is 2.0-6.0 nm, and the ratio of length to width is 1.5-3.5.

[0020] In the above technical solution, preferably, the length dimension of the crystal is 5.0-15.0 nm, and the width dimension is 2.5-5.0 nm.

[0021] In the above technical solution, preferably, the molecular sieve crystallization aid contains phenyl, and the content of phenyl is 1.5%-15%, preferably 5%-15%, based on the mass of the aid.

[0022] In the above technical solution, preferably, the molecular sieve crystallization aid is a suspension under normal temperature and pressure conditions.

[0023] The third aspect of the present invention provides a use of the above-mentioned molecular sieve crystallization aid in molecular sieve synthesis.

[0024] In the above technical solution, preferably, the molecular sieve crystallization aid is used in the synthesis of silicon-aluminum molecular sieves containing a 10-membered ring structure or a 12-membered ring structure.

[0025] In the above technical solution, preferably, the silicon-aluminum molecular sieve is a ZSM-5 molecular sieve.

[0026] In the above technical solution, preferably, the method for preparing the ZSM-5 molecular sieve comprises: mixing a silicon source, an aluminum source, an alkali source, an organic template, the molecular sieve crystallization aid and water, and crystallizing to obtain the ZSM-5 molecular sieve.

[0027] In the above technical solution, the silicon source, aluminum source, alkali, and organic template are the silicon source, aluminum source, alkali source, and organic template conventionally used in the synthesis of ZSM-5 in the art.

[0028] In the above technical scheme, the reaction mixture is calculated by molar ratio of SiO2:Al2O3:template:OH-:H2O=1:(0.005~0.05):(0.05~0.2):(0.01~0.1):(10~20).

[0029] In the above technical solution, the ratio of the mass of phenyl in the molecular sieve crystallization aid to the total mass of the silicon source calculated as SiO2 and the aluminum source calculated as Al2O3 is (0.005-0.06):1.

[0030] In the above technical solution, the crystallization temperature is 150-180° C., and the crystallization time is 6-30 hours, preferably 10-12 hours.

[0031] In the above technical solution, the grain size of the ZSM-5 molecular sieve is 30 to 800 nm, preferably 50 to 400 nm.

[0032] Compared with the prior art, the present invention has the following beneficial effects:

[0033] 1. The molecular sieve crystallization aid of the present invention is a suspension at room temperature and pressure. The size of the crystals in the molecular sieve crystallization aid is relatively small, with a length size range of only 5.0-18.0 nm and a width size range of only 2.0-6.0 nm. Compared with conventional powder molecular sieve crystallization aids, it has the advantages of a small and large number of crystal nuclei during the molecular sieve crystallization process, which can significantly shorten the crystallization time of the molecular sieve and reduce the grain size of the molecular sieve.

[0034] 2. The inventors have found through research that by controlling the phenyl content in the organic matter 2 and the treatment temperature, a specific molecular sieve crystallization aid of the present invention can be obtained, wherein controlling the phenyl content in the organic matter 2 is beneficial to inhibiting the growth of crystal size during the molecular sieve crystallization process, acting as a growth inhibitor, thereby reducing the molecular sieve grain size; controlling the treatment temperature to obtain a large number of crystal nuclei of the molecular sieve crystallization aid is beneficial to accelerating the nucleation rate during the molecular sieve crystallization process and shortening the molecular sieve crystallization time. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 This is a TEM photo of the crystals in the molecular sieve crystallization aid prepared in Example 1 of the present invention;

[0036] Figure 2 This is a TEM photo of the crystals in the molecular sieve crystallization aid prepared in Comparative Example 1 of the present invention;

[0037] Figure 3This is a TEM photo of the crystals in the molecular sieve crystallization aid prepared in Comparative Example 2 of the present invention;

[0038] Figure 4 XRD spectrum of the molecular sieve prepared in Example 4 of the present invention;

[0039] Figure 5 This is a SEM photo of the molecular sieve prepared in Example 4 of the present invention;

[0040] Figure 6 The XRD spectrum of the molecular sieve prepared in Comparative Example 3 of the present invention;

[0041] Figure 7 XRD spectrum of the molecular sieve prepared in Comparative Example 4 of the present invention;

[0042] Figure 8 This is a SEM photograph of the molecular sieve prepared in Comparative Example 4 of the present invention. DETAILED DESCRIPTION

[0043] The present invention is described in detail below in conjunction with specific implementation modes, but it should be understood that the protection scope of the present invention is not limited by the specific implementation modes.

[0044] In the present invention, the size of the crystals in the molecular sieve crystallization aid is obtained by analyzing TEM photos. The TEM photos are obtained by testing with a G2F30 transmission electron microscope produced by FEI Company of the United States. Before the test, a large amount of ethanol needs to be added to the sample to be tested, ultrasonically dispersed evenly, and then the suspension is dripped onto the copper mesh. After the ethanol evaporates completely, the test can be carried out.

[0045] In the present invention, the XRD spectrum of the molecular sieve is obtained by using the Ultima IV X-ray powder diffractometer of Rigaku Company of Japan. The voltage is selected as 35 kV, the current is selected as 30 mA, and the scanning speed is 1°·min- 1 When scanning at a wide angle, the 2θ angle is 5-35°.

[0046] In the present invention, a Hitachi S-4800 cold field emission high-resolution scanning electron microscope produced by Hitachi is used to obtain the SEM photograph.

[0047] [Example 1]

[0048] This embodiment is used to synthesize a molecular sieve crystallization aid. The specific preparation process is as follows: 208.3 grams of tetraethyl silicate, 6.7 grams of aluminum sulfate 18hydrate, 360 grams of water, 61 grams of tetrapropylammonium hydroxide and 63.6 grams of organic matter 2 (the structural formula of organic matter 2 is wherein R1, R3, R4 and R6 are phenyl groups, and R2 and R5 are methyl groups) are uniformly mixed to obtain a mixture A1, and then the mixture A1 is stirred at 70° C. in a closed space for 5 hours, and then cooled to room temperature to obtain a molecular sieve crystallization aid B1.

[0049] The TEM image of the crystal B1 in the molecular sieve crystallization aid is as follows: Figure 1 As shown, the two-dimensional image is a rectangle with a length dimension of 13.2 nm, a width dimension of 4.2 nm, and a length-to-width ratio of 3.1. After calculation, the phenyl content in the molecular sieve crystallization aid is 6.9%.

[0050] [Example 2]

[0051] This embodiment is used to synthesize a molecular sieve crystallization aid. The specific preparation process is as follows: 400 grams of tetraphenyl silicate, 540 grams of water, 147 grams of tetraethylammonium hydroxide and 54.4 grams of organic matter 2 (the structural formula of organic matter 2 is, wherein R1 and R4 are phenyl groups, and R2, R3, R5 and R6 are methyl groups) are mixed evenly to obtain a mixture A2, and then the mixture A2 is treated at 85° C. in a closed space for 4 hours, and then cooled to room temperature to obtain a molecular sieve crystallization aid B2.

[0052] The TEM photo of the crystal B2 in the molecular sieve crystallization aid is a rectangular image with a length dimension of 18.0 nm, a width dimension of 5.6 nm, and a length-to-width ratio of 3.2. After calculation, the phenyl content in the molecular sieve crystallization aid is 1.6%.

[0053] [Example 3]

[0054] This embodiment is used to synthesize a molecular sieve crystallization aid. The specific preparation process is as follows: 208.3 grams of tetraethyl silicate, 5.1 grams of pseudo-boehmite, 90 grams of water, 20.3 grams of tetrapropylammonium hydroxide and 64.7 grams of organic matter 2 (the structural formula of organic matter 2 is wherein R1, R2, R3, R4, R5 and R6 are all phenyl groups) are uniformly mixed to obtain a mixture A3, and then the mixture A3 is stirred in a closed space at 60° C. for 24 hours, and then cooled to room temperature to obtain a molecular sieve crystallization aid B3.

[0055] The TEM photo of the crystal B3 in the molecular sieve crystallization aid is a rectangular two-dimensional image with a length dimension of 5.0 nm, a width dimension of 2.8 nm, and a length-to-width ratio of 1.8. After calculation, the phenyl content in the molecular sieve crystallization aid is 14.4%.

[0056] [Comparative Example 1]

[0057] Compared with Example 1, the only difference is that no organic matter 2 is added. The specific preparation process is as follows: 208.3 grams of tetraethyl silicate, 6.7 grams of aluminum sulfate 18hydrate, 360 grams of water and 61 grams of tetrapropylammonium hydroxide are mixed evenly to obtain a mixture A4, and then the mixture A4 is stirred at 70°C in a closed space for 5 hours, and then cooled to room temperature to obtain a molecular sieve crystallization aid B4.

[0058] The TEM image of the crystal B4 in the molecular sieve crystallization aid is as follows: Figure 2 As shown, the two-dimensional image is approximately circular with a size of 50-60 nm. The phenyl content in the molecular sieve crystallization aid is 0.

[0059] [Comparative Example 2]

[0060] Compared with Example 1, the only difference is that an equal mass of vinyltriethoxysilane is used to replace organic matter 2. The specific preparation process is as follows: 208.3 grams of tetraethyl silicate, 6.7 grams of aluminum sulfate 18hydrate, 360 grams of water, 61 grams of tetrapropylammonium hydroxide and 63.6 grams of vinyltriethoxysilane are mixed evenly to obtain a mixture A5, and then the mixture A5 is stirred at 70°C in a closed space for 5 hours, and then cooled to room temperature to obtain a molecular sieve crystallization aid B5.

[0061] The TEM image of the crystal B5 in the molecular sieve crystallization aid is as follows: Figure 3 As shown, the two-dimensional image is approximately circular, and there is adhesion, and the size is 70-90nm. The phenyl content in the molecular sieve crystallization aid is 0.

[0062] [Example 4]

[0063] The molecular sieve crystallization aid B1 prepared in Example 1 was added to the molecular sieve synthesis mother liquor to synthesize the ZSM-5 molecular sieve, specifically as follows: 60 g of white carbon black, 6.7 g of aluminum sulfate 18hydrate, 270 g of water, 20.3 g of tetrapropylammonium hydroxide, 2 g of sodium hydroxide and 12 g of the molecular sieve crystallization aid B1 were mixed evenly, and then treated at 160° C. for 12 hours in a closed space. After the end, the molecular sieve C1 was obtained by cooling, centrifugation, drying at 120° C. for 10 hours and calcining at 550° C. for 5 hours. The XRD spectrum of the molecular sieve C1 is shown in FIG. Figure 4 As shown, it is a typical characteristic peak of ZSM-5 molecular sieve. The SEM photo of molecular sieve C1 is shown in Figure 5 As shown, the grain size is 220-400nm.

[0064] [Comparative Example 3]

[0065] Compared with Example 4, the only difference is that the molecular sieve crystallization aid B1 is not added during the molecular sieve synthesis process. Specifically, 60 grams of white carbon black, 6.7 grams of aluminum sulfate 18hydrate, 270 grams of water, 20.3 grams of tetrapropylammonium hydroxide and 2 grams of sodium hydroxide are mixed evenly, and then treated at 160°C for 12 hours in a closed space. After the end, the molecular sieve C2 is obtained by cooling, centrifugation, drying at 120°C for 10 hours and calcining at 550°C for 5 hours. The XRD spectrum of the molecular sieve C2 is shown in FIG. Figure 6 As shown, the XRD baseline is uneven, and bulges appear at a 2Theta angle of about 20-25 degrees, indicating that the molecular sieve is not completely crystallized.

[0066] [Comparative Example 4]

[0067] Compared with Example 4, the difference is that the molecular sieve crystallization aid B1 is not added during the synthesis of the molecular sieve, and the closed treatment time is extended to 48 hours, specifically as follows: 60 grams of white carbon black, 6.7 grams of aluminum sulfate 18hydrate, 270 grams of water, 20.3 grams of tetrapropylammonium hydroxide and 2 grams of sodium hydroxide are mixed evenly, and then treated at 160°C in a closed space for 48 hours. After the end, the molecular sieve C3 is obtained by cooling, centrifugation, drying at 120°C for 10 hours and calcining at 550°C for 5 hours. The XRD spectrum of the molecular sieve C3 is shown as follows: Figure 7 As shown, it is a typical characteristic peak of ZSM-5 molecular sieve. The SEM photo of molecular sieve C3 is shown in Figure 8 As shown, the crystal size is 660-1100 nm. The above shows that adding the molecular sieve crystallization aid prepared by the present invention during the molecular sieve synthesis process can significantly shorten the crystallization time of the molecular sieve and reduce the crystal size of the molecular sieve.

[0068] [Example 5]

[0069] Compared with Example 4, the difference is that the crystallization aid B2 of Example 2 is added during the synthesis of the molecular sieve, and the closed treatment time is extended to 16 hours. Specifically as follows: the molecular sieve crystallization aid B2 prepared in Example 2 is added to the molecular sieve synthesis mother liquor to synthesize the ZSM-5 molecular sieve, specifically as follows: 60 grams of white carbon black, 6.7 grams of aluminum sulfate 18hydrate, 270 grams of water, 20.3 grams of tetrapropylammonium hydroxide, 2 grams of sodium hydroxide and 12 grams of molecular sieve crystallization aid B2 are mixed evenly, and then treated at 160°C in a closed space for 16 hours. After the end, it is cooled, centrifuged, dried at 120°C for 10 hours and calcined at 550°C for 5 hours to obtain molecular sieve C4. The XRD spectrum of molecular sieve C4 is the same as Figure 4 Similar to the characteristic peaks of typical ZSM-5 molecular sieves, the SEM photos of molecular sieve C4 are similar to Figure 5 Similarly, the crystal size of molecular sieve C4 is 430-650 nm.

[0070] [Example 6]

[0071] Compared with Example 4, the difference is that the crystallization aid B3 of Example 3 is added during the synthesis of the molecular sieve. Specifically, the molecular sieve crystallization aid B3 prepared in Example 3 is added to the molecular sieve synthesis mother liquor to synthesize the ZSM-5 molecular sieve, specifically as follows: 60 grams of white carbon black, 6.7 grams of aluminum sulfate 18hydrate, 270 grams of water, 20.3 grams of tetrapropylammonium hydroxide, 2 grams of sodium hydroxide and 12 grams of molecular sieve crystallization aid B3 are mixed evenly, and then treated at 160°C in a closed space for 12 hours. After the end, it is cooled, centrifuged, dried at 120°C for 10 hours and calcined at 550°C for 5 hours to obtain molecular sieve C5. The XRD spectrum of molecular sieve C5 is the same as Figure 4 Similar to the characteristic peaks of typical ZSM-5 molecular sieves, the SEM photo of molecular sieve C5 is similar to Figure 5 Similarly, the crystal size of molecular sieve C5 is 160-350 nm.

[0072] [Example 7]

[0073] Compared with Example 4, the difference is that the proportion of each material in the molecular sieve synthesis mother liquor is changed. Specifically, 60 grams of white carbon black, 30 grams of aluminum sulfate 18hydrate, 360 grams of water, 40 grams of tetrapropylammonium hydroxide, 4 grams of sodium hydroxide and 20 grams of molecular sieve crystallization aid B1 are mixed evenly, and then treated at 170°C for 10 hours in a closed space. After the end, the molecular sieve C9 is obtained by cooling, centrifugation, drying at 120°C for 10 hours and calcining at 550°C for 5 hours. The XRD spectrum of the molecular sieve C9 is the same as Figure 4 Similar to the characteristic peaks of typical ZSM-5 molecular sieves, the SEM photos of molecular sieve C9 are similar to Figure 5 Similarly, the crystal size of molecular sieve C9 is 200-360nm.

[0074] [Comparative Example 5]

[0075] Compared with Example 4, the difference is that the crystallization aid B4 of Comparative Example 1 is added during the synthesis of the molecular sieve, and the closed treatment time is extended to 36 hours. Specifically as follows: the molecular sieve crystallization aid B4 prepared in Comparative Example 1 is added to the molecular sieve synthesis mother liquor for ZSM-5 molecular sieve synthesis, specifically as follows: 60 grams of white carbon black, 6.7 grams of aluminum sulfate 18 water, 270 grams of water, 20.3 grams of tetrapropylammonium hydroxide, 2 grams of sodium hydroxide and 12 grams of molecular sieve crystallization aid B4 are mixed evenly, and then treated at 160°C in a closed space for 36 hours. After the end, the molecular sieve C6 is obtained by cooling, centrifugation, drying at 120°C for 10 hours and calcining at 550°C for 5 hours. The XRD spectrum of molecular sieve C6 shows the characteristic peaks of typical ZSM-5 molecular sieves, and the grain size of molecular sieve C6 is 520-880nm.

[0076] [Comparative Example 6]

[0077] Compared with Example 4, the difference is that the crystallization aid B5 of Comparative Example 2 is added during the synthesis of the molecular sieve, and the closed treatment time is extended to 36 hours. Specifically as follows: the molecular sieve crystallization aid B5 prepared in Comparative Example 2 is added to the molecular sieve synthesis mother liquor for ZSM-5 molecular sieve synthesis, specifically as follows: 60 grams of white carbon black, 6.7 grams of aluminum sulfate 18 water, 270 grams of water, 20.3 grams of tetrapropylammonium hydroxide, 2 grams of sodium hydroxide and 12 grams of molecular sieve crystallization aid B5 are mixed evenly, and then treated at 160°C in a closed space for 36 hours, and then cooled, centrifuged, dried at 120°C for 10 hours and calcined at 550°C for 5 hours to obtain molecular sieve C7. The XRD spectrum of molecular sieve C7 shows the characteristic peaks of typical ZSM-5 molecular sieves, and the grain size of molecular sieve C7 is 580-950nm.

[0078] [Comparative Example 7]

[0079] Synthesis of molecular sieve crystallization aid:

[0080] 208.3 g of tetraethyl silicate, 6.7 g of aluminum sulfate 18-hydrate, 360 g of water, 61 g of tetrapropylammonium hydroxide and 63.6 g of organic matter 2 (the structural formula of organic matter 2 is wherein R1, R3, R4 and R6 are phenyl groups, and R2 and R5 are methyl groups) are mixed evenly to obtain a mixture A6, and then the mixture A6 is stirred in a closed space at 150° C. for 48 hours, and then cooled to room temperature, filtered, washed and dried to obtain a molecular sieve crystallization aid B6.

[0081] The crystals in the molecular sieve crystallization aid B6 are powders with a size of 300-800 nm.

[0082] Synthesis of molecular sieves:

[0083] The molecular sieve crystallization aid B6 prepared above is added to the molecular sieve synthesis mother liquor to synthesize the ZSM-5 molecular sieve, specifically as follows: 60 grams of white carbon black, 6.7 grams of aluminum sulfate 18hydrate, 270 grams of water, 20.3 grams of tetrapropylammonium hydroxide, 2 grams of sodium hydroxide and 20 grams of molecular sieve crystallization aid B6 are mixed evenly, and then treated at 160°C in a closed space for 48 hours. After the end, the molecular sieve C8 is obtained by cooling, centrifugation, drying at 120°C for 10 hours and calcining at 550°C for 5 hours. The XRD spectrum of the molecular sieve C8 shows the typical characteristic peaks of the ZSM-5 molecular sieve, and the grain size of the molecular sieve C8 is 550-1050nm.

[0084] The above describes the specific implementation of the present invention in detail, but the present invention is not limited thereto. Within the technical concept of the present invention, the technical solution of the present invention can be subjected to a variety of simple modifications, including the various technical features being combined in any other suitable manner, and these simple modifications and combinations should also be regarded as the contents disclosed by the present invention and belong to the protection scope of the present invention.

Claims

1. A method for preparing a molecular sieve crystallization aid, comprising the following steps: (a) contacting a silicon source, an aluminum source, water, an organic substance 1 and an organic substance 2 to obtain a mixture A; (b) treating the mixture A to obtain a molecular sieve crystallization aid.

2. The preparation method according to claim 1, characterized in that: The silicon source in step (a) is one or more of tetramethyl silicate, tetraethyl silicate, tetrapropyl silicate, tetrabutyl silicate and tetraphenyl silicate, preferably one or more of tetraethyl silicate, tetrapropyl silicate and tetraphenyl silicate; And / or, the aluminum source is one or more of aluminum sulfate, aluminum isopropoxide, sodium aluminate, and pseudo-boehmite, preferably one or more of aluminum sulfate and pseudo-boehmite; And / or, the organic matter 1 is one or more of tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrapropylammonium hydroxide, tetrabutylammonium hydroxide, ethylamine, ethylenediamine, n-butylamine, butylenediamine, hexamethyleneimine, piperidine, piperazine, and dicyclohexylamine, preferably one or more of tetraethylammonium hydroxide, tetrapropylammonium hydroxide, ethylamine, n-butylamine, and hexamethyleneimine.

3. The preparation method according to claim 1 or 2, characterized in that: The structural formula of the organic compound 2 in step (a) is Wherein R1-R6 are each independently selected from methyl, ethyl, propyl or phenyl.

4. The preparation method according to claim 3, characterized in that: At least one of R1-R6 is a phenyl group, preferably 4 to 6 phenyl groups.

5. The preparation method according to claim 1, characterized in that: The molar ratio of silicon source, aluminum source, water and organic matter 1 is silicon source: aluminum source: water: organic matter 1 = 1: (0-0.05): (5-30): (0.1-1), the silicon source is calculated as SiO2, and the aluminum source is calculated as Al2O3; And / or, the ratio of the mass of organic matter 2 to the sum of the total mass of silicon source, aluminum source, water and organic matter 1 is (0.05-0.2):1, the silicon source is calculated as SiO2, and the aluminum source is calculated as Al2O3.

6. The preparation method according to claim 1, characterized in that: The treatment condition in step (b) is 60-85° C. for 4-24 hours, preferably a closed treatment.

7. The molecular sieve crystallization aid obtained according to the preparation method according to any one of claims 1 to 6.

8. The molecular sieve crystallization aid according to claim 7, characterized in that: The two-dimensional image of the crystal in the molecular sieve crystallization aid is a rectangle, the length dimension of the crystal is 5.0-18.0 nm, the width dimension is 2.0-6.0 nm, and the ratio of length to width is 1.5-3.

5.

9. The molecular sieve crystallization aid according to claim 7, characterized in that: The molecular sieve crystallization aid contains phenyl, and the content of phenyl is 1.5%-15%, preferably 5%-15%.

10. The molecular sieve crystallization aid according to claim 1, characterized in that: The molecular sieve crystallization aid is a suspension at room temperature and pressure.

11. Use of the molecular sieve crystallization aid according to any one of claims 7 to 10 in the synthesis of molecular sieves, preferably in the synthesis of silicon-aluminum molecular sieves containing a 10-membered ring structure or a 12-membered ring structure.

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