Method for synthesizing high-crystallinity AlPO4-9 zeolite molecular sieve without mineralizer

Abstract

The invention relates to a mineralizer-free method for synthesizing a high-crystallinity AlPO4-9 zeolite molecular sieve, which comprises the following steps: sequentially adding an aluminum source, an inorganic structure-directing agent, an organic structure-directing agent and a phosphorus source into water, then continuously stirring for 2 hours, and then carrying out crystallization reaction at 170-210 DEG C for 72-120 hours to obtain the high-crystallinity AlPO4-9 zeolite molecular sieve, and washing the obtained product with deionized water according to the ratio of 1: 10, and drying at 80 DEG C for 4 hours to obtain a target product. The synthesis method does not need to use a mineralizer, reduces the use amount of an organic structure-directing agent, greatly reduces the preparation cost of the zeolite, improves the crystallinity and hydrothermal stability of the zeolite by optimizing the molar ratio, crystallization temperature, time and other parameters, and has very strong practical applicability and theoretical research value.

Description

Technical Field

[0001] The present invention relates to a method for synthesizing highly crystalline AlPO4-9 zeolite molecular sieve without a mineralizer, belonging to the technical field of zeolite molecular sieves. Background Art

[0002] AlPO4-n is a class of zeolite molecular sieve materials with a phosphoaluminate framework. Its framework does not contain Si, and the basic constituent elements are P, Al, and O. The basic units are AlO4 and PO4 tetrahedra, which are strictly arranged alternately, making the overall framework electrically neutral. Due to the special framework structure and compositional characteristics of the phosphoaluminate zeolite molecular sieve, it has a high specific surface area, excellent thermal stability and hydrothermal stability, regular pore arrangement, excellent shape selectivity, and moderate surface hydrophilicity. These advantages have attracted extensive research interest and application exploration in the fields of industrial catalysis, adsorption separation, etc.

[0003] Among them, AlPO4-9 zeolite molecular sieve is a special member of aluminophosphate zeolite molecular sieves. In the framework of AlPO4-9 zeolite molecular sieve, all phosphorus atoms form four-coordination with oxygen, and among the six aluminum atoms, one aluminum atom (Al-1) forms six-coordination with the oxygen atoms of the phosphate group, and the remaining five aluminum atoms (Al-2 to Al-6) are four-coordinated. Finally, each AlO4 tetrahedron is connected to four PO4 tetrahedra through Al–O–P bonds, thus constituting the basic framework of the AlPO4-9 zeolite molecular sieve.

[0004] However, the AlPO4-9 zeolite molecular sieve prepared by traditional synthesis methods is severely restricted in its practical industrial applications due to the necessity of using expensive and environmentally unfriendly organic templating agents and mineralizers. Therefore, the present invention attempts to investigate different aluminum sources without the action of a mineralizer, and at the same time, by introducing an inorganic structure-directing agent into the synthesis system and mixing it with an organic structure-directing agent to form a co-templating agent, reducing the dosage of the organic templating agent, and combining the optimization of process parameters such as the feed ratio, crystallization temperature, and time, so as to achieve the purpose of synthesizing a highly crystalline AlPO4-9 zeolite molecular sieve and effectively reducing the preparation cost. Summary of the Invention

[0005] How to synthesize a highly crystalline AlPO4-9 zeolite molecular sieve without relying on a mineralizer and reducing the organic structure-directing effect is the technical problem to be solved by the present invention. The present invention provides a method for synthesizing a highly crystalline AlPO4-9 zeolite molecular sieve without a mineralizer.

[0006] To achieve the above object, the present invention is realized through the following technical solutions:

[0007] A method for synthesizing highly crystalline AlPO4-9 zeolite molecular sieve without mineralizer, comprising the following process: using pseudo-boehmite or aluminum isopropoxide or aluminum hydroxide as the aluminum source, 85% wt phosphoric acid aqueous solution as the phosphorus source, ammonium fluoride or ammonium chloride or sodium chloride as the inorganic structure directing agent, crystallizing at 170-210 °C for 72-120 h, washing the obtained product with deionized water in a ratio of 1:10, and drying at 80 °C for 4 h to obtain the highly crystalline AlPO4-9 zeolite molecular sieve.

[0008] To achieve the above object, the present invention is realized through the following technical solutions:

[0009] (1) Add the aluminum source, inorganic structure directing agent, organic structure directing agent, and phosphorus source into water in sequence. After adding each raw material, stir evenly and then add other raw materials;

[0010] (2) Continue to stir for several hours after adding all the raw materials;

[0011] (3) Carry out a crystallization reaction on the mixture at 170-210 °C for 72-120 hours;

[0012] (4) After the crystallization reaction ends, carry out suction filtration and washing, and obtain the highly crystalline AlPO4-9 zeolite molecular sieve after drying;

[0013] The aluminum source is measured by Al2O3, the phosphorus source is measured by P2O5, the inorganic structure directing agent is measured by halogen element X, and the organic structure directing agent is measured by piperazine (pipe). The molar ratio of each raw material feed is Al2O3:P2O5:pipe:X:H2O = 1.0:1.0:(0.39-0.59):0.19:100.

[0014] Further, in the synthesis method, the aluminum source is pseudo-boehmite or aluminum isopropoxide or aluminum hydroxide.

[0015] More preferably, in the synthesis method, the aluminum source is aluminum hydroxide.

[0016] Further, in the synthesis method, the inorganic structure directing agent is selected from sodium chloride or ammonium chloride or ammonium fluoride.

[0017] The pseudo-boehmite, aluminum isopropoxide, aluminum hydroxide, 85% wt phosphoric acid aqueous solution, piperazine, sodium chloride, ammonium chloride, and ammonium fluoride described in the present invention are all industrial products. Preferably, the molar ratio of each raw material feed is Al2O3:P2O5:pipe:X:H2O = 1.0:1.0:0.59:(0.19-0.59):100.

[0018] Preferably, the temperature of the crystallization reaction in step (3) is 190 °C; the time of the crystallization reaction is 84 h.

[0019] Preferably, the washing in step (4) is carried out by operating the obtained product and deionized water in a ratio of 1:10; the drying temperature is 80 °C and the time is 4 h.

[0020] More preferably, in one embodiment of the present invention, the molar ratio of the feedstocks in the synthesis method is Al2O3:P2O5:pipe:X:H2O = 1.0:1.0:0.59:0.19:100, and the inorganic structure-directing agent is ammonium chloride.

[0021] The crystallization reaction described in the present invention is basically the same as the conditions and equipment used for synthesizing traditional zeolite molecular sieves.

[0022] Furthermore, the hydrothermal crystallization temperature in the synthesis method is 170 - 210 °C.

[0023] More preferably, the hydrothermal crystallization temperature in the synthesis method is 190 °C.

[0024] Furthermore, the hydrothermal crystallization time in the synthesis method is 72 - 120 h.

[0025] More preferably, the hydrothermal crystallization time in the synthesis method is 84 h.

[0026] Further, the drying temperature in the synthesis method is 70 - 100 °C and the time is 4 - 8 h.

[0027] More preferably, the drying temperature in the synthesis method is 80 °C and the time is 4 h.

[0028] Beneficial technical effects:

[0029] For the first time in the aluminum phosphate system without a mineralizer, an inorganic structure-directing agent is used to replace a part of the organic structure-directing agent to synthesize highly crystalline AlPO4-9 zeolite molecular sieve. Compared with the synthesis methods described in the literature, it greatly reduces the dependence on a large amount of organic template agents in the traditional synthesis method, eliminates the influence of the mineralizer on the synthesis system, and finds an environmentally friendly and low-cost synthesis route. Description of the Drawings

[0030] Figure 1 XRD patterns of AlPO4-9 zeolite molecular sieves synthesized from different aluminum sources. Among them, a represents aluminum hydroxide (Example 3), b represents pseudoboehmite (Example 1), and c represents aluminum isopropoxide (Example 2).

[0031] Figure 2 XRD patterns of AlPO4-9 zeolite molecular sieves synthesized from different types of inorganic structure-directing agents. Among them, a represents sodium chloride + piperazine (Example 4), b represents ammonium chloride + piperazine (Example 5), and c represents ammonium fluoride + piperazine (Example 6).

[0032] Figure 3 XRD patterns of AlPO4-9 zeolite molecular sieves synthesized with different ratios of inorganic structure-directing agents to organic structure-directing agents. Among them, a represents the material ratio of Al2O3:P2O5:pipe:NH4Cl:H2O = 1.0:1.0:0.78:0:100 (Example 2), b represents the material ratio of Al2O3:P2O5:pipe:NH4Cl:H2O = 1.0:1.0:0.19:0.59:100 (Example 7), c represents the material ratio of Al2O3:P2O5:pipe:NH4Cl:H2O = 1.0:1.0:0.39:0.39:100 (Example 5), d represents the material ratio of Al2O3:P2O5:pipe:NH4Cl:H2O = 1.0:1.0:0.59:0.19:100 (Example 8), and e represents the material ratio of Al2O3:P2O5:pipe:NH4Cl:H2O = 1.0:1.0:0:0.78:100 (Example 9).

[0033] Figure 4 XRD patterns of AlPO4-9 zeolite molecular sieves synthesized at different temperatures. Among them, a represents 210 °C (Example 14), b represents 200 °C (Example 13), c represents 190 °C (Example 12), d represents 180 °C (Example 11), and e represents 170 °C (Example 10).

[0034] Figure 5 XRD patterns of AlPO4-9 zeolite molecular sieves synthesized for different times. Among them, a represents 72 h (Example 15), b represents 84 h (Example 16), c represents 96 h (Example 16), a represents 108 h (Example 18), and a represents 120 h (Example 19).

[0035] Figure 6 XRD patterns of AlPO4-9 synthesized in the comparative example and AlPO4-9 zeolite molecular sieve synthesized in the example. Among them, a represents Example 16 and b represents Comparative Example 1.

[0036] Figure 7 SEM image of the AlPO4-9 zeolite molecular sieve prepared in Example 16.

[0037] Figure 8 N2 adsorption-desorption isotherm and pore size distribution curve of the AlPO4-9 zeolite molecular sieve prepared in Example 16. Detailed implementation manners

[0038] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the embodiments and drawings of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and in no way limits the present invention and its application or use. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention.

[0039] Unless otherwise specifically stated, the numerical values set forth in these embodiments do not limit the scope of the present invention. Technologies and methods known to those of ordinary skill in the relevant art may not be discussed in detail, but where appropriate, the said technologies and methods should be regarded as part of the specification. In all examples shown and discussed herein, any specific value should be construed as merely exemplary and not as a limitation. Therefore, other examples of the exemplary embodiments may have different values.

[0040] Solution A used in the following examples: Prepared by dissolving 9.34 g of piperazine in 250 mL of H2O.

[0041] In the description of "the molar ratio of each material Al2O3:P2O5:pipe:X:H2O" in the following examples and comparative examples, Al2O3 refers to the aluminum source, and the number of moles of the aluminum source is the number of moles of aluminum element in aluminum hydroxide; P2O5 refers to the phosphorus source, and the number of moles of the phosphorus source is the number of moles of phosphorus element in phosphoric acid; the inorganic structure-directing agent is a compound containing halogen elements, represented by X.

[0042] Testing and calculation method of crystallinity (%): Crystallinity is tested using an X-ray diffractometer, and the calculation formula is: Crystallinity = (diffraction peak intensity / total intensity) * 100%, and data processing is performed using jade software.

[0043] S BET Measured by nitrogen adsorption using a physical adsorption instrument.

[0044] Experimental Example 1

[0045] Solution A: Prepared by dissolving 9.34 g of piperazine in 250 mL of H2O.

[0046] Take 1.361 g of pseudo-boehmite and slowly add 30 mL of Solution A dropwise thereto. After stirring for 2 h, slowly add 2.28 mL of 85% wt phosphoric acid aqueous solution dropwise, and then stir for another 2 h. Load the obtained mixture into a high-pressure reactor and hydrothermally crystallize it in an oven at 180 °C for 120 h. Wash the product obtained from the reaction with deionized water at a ratio of 1:10 and then dry it at 80 °C for 4 h. The feeding molar ratio of each material in the system is Al2O3:P2O5:pipe:X:H2O, denoted as 1.0:1.0:0.78:0:100. The crystallinity of the prepared AlPO4-9 zeolite molecular sieve is shown in Table 1.

[0047] Experimental Example 2

[0048] Solution A: Prepared by dissolving 9.34 g of piperazine in 250 mL of H2O.

[0049] Take 3.443 g of aluminum isopropoxide and slowly add 30 mL of Solution A dropwise thereto. After stirring for 2 h, slowly add 2.28 mL of 85% wt phosphoric acid aqueous solution dropwise, and then stir for another 2 h. Load the obtained mixture into a high-pressure reactor and hydrothermally crystallize it in an oven at 180 °C for 120 h. Wash the product obtained from the reaction with deionized water at a ratio of 1:10 and then dry it at 80 °C for 4 h. The feeding molar ratio of each material in the system is Al2O3:P2O5:pipe:X:H2O, denoted as 1.0:1.0:0.78:0:100. The crystallinity of the prepared AlPO4-9 zeolite molecular sieve is shown in Table 1.

[0050] Experimental Example 3

[0051] Solution A: Prepared by dissolving 9.34 g of piperazine in 250 mL of H2O.

[0052] Take 1.316 g of aluminum hydroxide and slowly add 30 mL of Solution A dropwise thereto. After stirring for 2 h, slowly add 2.28 mL of 85% wt phosphoric acid aqueous solution dropwise, and then stir for another 2 h. Load the obtained mixture into a high-pressure reactor and hydrothermally crystallize it in an oven at 180 °C for 120 h. Wash the product obtained from the reaction with deionized water at a ratio of 1:10 and then dry it at 70 °C for 8 h. The feeding molar ratio of each material in the system is Al2O3:P2O5:pipe:X:H2O, denoted as 1.0:1.0:0.78:0:100. The crystallinity of the prepared AlPO4-9 zeolite molecular sieve is shown in Table 1.

[0053] Experimental Example 4

[0054] Measure 30 ml of H2O, add 0.3772 g of NaCl to it, stir for 10 min, then add 0.5599 g of pipe, after stirring evenly, add 1.316 g of Al(OH)3, stir for 2 h, and then add 2.28 ml of 85% wt phosphoric acid aqueous solution drop by drop, and stir for another 2 h. Load the obtained mixture into a high-pressure reaction kettle and place it in an oven at 180 °C for hydrothermal crystallization for 120 h. Wash the product obtained from the reaction with deionized water in a ratio of 1:10 and dry it at 70 °C for 8 h. The feeding molar ratio of each material in the system is based on Al2O3:P2O5:pipe:X:H2O, denoted as 1.0:1.0:0.5:0.5:100. The crystallinity of the prepared AlPO4-9 zeolite molecular sieve is shown in Table 1.

[0055] Experimental Example 5

[0056] Measure 30 ml of H2O, add 0.2409 g of NH4F to it, stir for 10 min, then add 0.5599 g of pipe, after stirring evenly, add 1.316 g of Al(OH)3, stir for 2 h, and then add 2.28 ml of 85% wt phosphoric acid aqueous solution drop by drop, and stir for another 2 h. Load the obtained mixture into a high-pressure reaction kettle and place it in an oven at 180 °C for hydrothermal crystallization for 120 h. Wash the product obtained from the reaction with deionized water in a ratio of 1:10 and dry it at 100 °C for 8 h. The feeding molar ratio of each material in the system is based on Al2O3:P2O5:pipe:X:H2O, denoted as 1.0:1.0:0.5:0.5:100. The crystallinity of the prepared AlPO4-9 zeolite molecular sieve is shown in Table 1.

[0057] Experimental Example 6

[0058] Measure 30 ml of H2O, add 0.3478 g of NH4Cl to it, stir for 10 min, then add 0.5599 g of pipe, after stirring evenly, add 1.316 g of Al(OH)3, stir for 2 h, and then add 2.28 ml of 85% wt phosphoric acid aqueous solution drop by drop, and stir for another 2 h. Load the obtained mixture into a high-pressure reaction kettle and place it in an oven at 180 °C for hydrothermal crystallization for 120 h. Wash the product obtained from the reaction with deionized water in a ratio of 1:10 and dry it at 100 °C for 8 h. The feeding molar ratio of each material in the system is based on Al2O3:P2O5:pipe:X:H2O, denoted as 1.0:1.0:0.5:0.5:100. The crystallinity of the prepared AlPO4-9 zeolite molecular sieve is shown in Table 1.

[0059] Experimental Example 7

[0060] Measure 30 ml of H2O, add 0.1739 g of NH4Cl to it, stir for 10 min, then add 0.8399 g of pipe, after stirring evenly, add 1.316 g of Al(OH)3, stir for 2 h, and then dropwise add 2.28 ml of 85% wt phosphoric acid aqueous solution, and stir for another 2 h. Load the obtained mixture into a high-pressure reaction kettle and place it in an oven at 180 °C for hydrothermal crystallization for 120 h. Wash the product obtained from the reaction with deionized water at a ratio of 1:10 and dry it at 80 °C for 4 h. The feeding molar ratio of each material in the system is expressed as Al2O3:P2O5:pipe:X:H2O, denoted as 1.0:1.0:0.19:0.59:100. The crystallinity of the prepared AlPO4-9 zeolite molecular sieve is shown in Table 1.

[0061] Experimental Example 8

[0062] Measure 30 ml of H2O, add 0.5217 g of NH4Cl to it, stir for 10 min, then add 0.2800 g of pipe, after stirring evenly, add 1.316 g of Al(OH)3, stir for 2 h, and then dropwise add 2.28 ml of 85% wt phosphoric acid aqueous solution, and stir for another 2 h. Load the obtained mixture into a high-pressure reaction kettle and place it in an oven at 180 °C for hydrothermal crystallization for 120 h. Wash the product obtained from the reaction with deionized water at a ratio of 1:10 and dry it at 80 °C for 4 h. The feeding molar ratio of each material in the system is expressed as Al2O3:P2O5:pipe:X:H2O, denoted as 1.0:1.0:0.19:0.59:100. The crystallinity of the prepared AlPO4-9 zeolite molecular sieve is shown in Table 1.

[0063] Experimental Example 9

[0064] Measure 30 ml of H2O, add 0.6956 g of NH4Cl to it, stir evenly, then add 1.316 g of Al(OH)3, stir for 2 h, and then dropwise add 2.28 ml of 85% wt phosphoric acid aqueous solution, and stir for another 2 h. Load the obtained mixture into a high-pressure reaction kettle and place it in an oven at 180 °C for hydrothermal crystallization for 120 h. Wash the product obtained from the reaction with deionized water at a ratio of 1:10 and dry it at 80 °C for 4 h. The feeding molar ratio of each material in the system is expressed as Al2O3:P2O5:pipe:X:H2O, denoted as 1.0:1.0:0.19:0.59:100. The crystallinity of the prepared AlPO4-9 zeolite molecular sieve is shown in Table 1.

[0065] Experimental Examples 10 - 14

[0066] The preparation method of the products in Examples 10 - 14 is the same as that in Example 9, except that the crystallization reaction temperature is different.

[0067] The crystallization reaction temperature of Example 10 is 170 °C.

[0068] The crystallization reaction temperature of Example 11 is 180 °C.

[0069] The crystallization reaction temperature of Example 12 is 190 °C.

[0070] The crystallization reaction temperature of Example 13 is 200 °C.

[0071] The crystallization reaction temperature of Example 14 is 210 °C.

[0072] The crystallinity of the prepared AlPO4-9 zeolite molecular sieve is shown in Table 1.

[0073] Experimental Examples 15 to 19

[0074] The preparation method of the products of Examples 15 to 19 is the same as that of Example 9, except that the crystallization reaction time is different.

[0075] The crystallization reaction time of Example 15 is 72 h.

[0076] The crystallization reaction time of Example 16 is 84 h.

[0077] The crystallization reaction time of Example 17 is 96 h.

[0078] The crystallization reaction time of Example 18 is 108 h.

[0079] The crystallization reaction time of Example 19 is 120 h.

[0080] The crystallinity of the prepared AlPO4-9 zeolite molecular sieve is shown in Table 1.

[0081] Comparative Example 1:

[0082] Prepared by the method reported in the literature "Synthesis and structure of AlPO4-9: An unacquainted member in the family of microporous aluminophosphates": First, dissolve 1.72 g of Al(iPrO)3 in a solution of 15 mL of 0.434 mol / L piperazine and 2 mL of ethylene glycol. Then, add 1.14 mL of phosphoric acid (85%) and stir for 1 h. Autoclave the homogeneous gel with a molar ratio at 170 °C or 180 °C for 5 days. After cooling to room temperature, filter off the solid, wash with deionized water, and dry at 80 °C to obtain a colorless crystalline product.

[0083] The molar ratio of each material in the system is Al2O3:P2O5:pipe:EG:H2O = 1.0:1.0:0.78:4.3:100.

[0084] The reaction parameters of the above examples and comparative examples are shown in Table 1.

[0085] The products of the above examples and comparative examples were subjected to XRD testing and the crystallinity was calculated. The results are shown in Table 1.

[0086] Table 1 Preparation parameters and textural properties of examples and comparative examples

[0087]

[0088] Results and discussion:

[0089] From Table 1 and Figure 1 It can be seen that using piperazine (pipe) as the organic structure-directing agent and phosphoric acid as the phosphorus source, under the condition of no mineralizer, AlPO4-9 zeolite molecular sieve was synthesized using pseudoboehmite, aluminum isopropoxide, and aluminum hydroxide respectively. Only when using aluminum hydroxide as the aluminum source could AlPO4-9 zeolite molecular sieve be successfully synthesized. The reason may be that the properties of the aluminum source have an important influence on the crystallization process of AlPO4-9 zeolite molecular sieve and the physicochemical properties of the product. Aluminum isopropoxide and pseudoboehmite are insoluble in water and only soluble in organic solvents. Therefore, in the absence of the mineralizer ethylene glycol, the added aluminum source cannot completely enter the hydrothermal reaction system, resulting in P2O5 / Al2O3≠1 in the finally formed zeolite molecular sieve framework; while aluminum hydroxide, due to its unique physical properties, can dissolve in water and quickly mix evenly with the piperazine solution to react under the condition of no mineralizer, forming hydroxyl radicals. Since hydroxyl radicals have excellent catalytic activity for the depolymerization of aluminophosphate species and the repolymerization around the cationic template agent during the formation of the molecular sieve, the nucleation of the zeolite molecular sieve can be significantly accelerated. Therefore, only when using aluminum hydroxide as the aluminum source can AlPO4-9 zeolite molecular sieve be successfully synthesized.

[0090] From Figure 2 It can be seen that when an inorganic structure-directing agent is introduced into the synthesis system, when the inorganic structure-directing agent is ammonium chloride and the material ratio is Al2O3:P2O5:pipe:X:H2O = 1.0:1.0:0.59:0.19:100, AlPO4-9 zeolite molecular sieve can be successfully synthesized. When the template agent composition is sodium chloride-piperazine, AlPO4-9 zeolite molecular sieve cannot be synthesized. The reason may be the introduction of a new metal cation Na + , and Na +The introduction of [substance] is not conducive to the formation of the neutral framework of AlPO4-9 zeolite molecular sieve. When the template agent composition is ammonium fluoride-piperazine and ammonium chloride-piperazine, AlPO4-9 zeolite molecular sieve can be synthesized. The reason may be the anions in the inorganic ammonium salt template agent, such as F - and Cl - can not only play a mineralization role but also a structure-directing role, generating a framework structure containing primary cage-like structural units. In addition, the ammonium ion with a positive charge can provide hydrogen protons to the Al(OH)3 species formed in the zeolite synthesis gel, and the N element on the template agent has strong activity, which can induce the nucleation of raw materials, so it acts on the uniformly mixed synthesis system and is encapsulated into the crystal structure during the hydrothermal crystallization process, ultimately promoting the formation of the zeolite framework. The crystallinity of the AlPO4-9 zeolite molecular sieve synthesized with ammonium chloride-piperazine as the template agent composition is better than that with ammonium fluoride-piperazine. The reason may be that ammonium fluoride and aluminum hydroxide form a proton solution after dissolving in water, and the nucleophilicity of fluorine is less than that of chlorine.

[0091] To explore the optimal molar ratio of ammonium chloride and piperazine in the reaction system, combined with Table 1, Figure 3 and considering the comprehensive factors of environmental protection, economy and crystallinity, we selected ammonium chloride-piperazine as the template agent composition. In the ammonium chloride-piperazine system, piperazine still mainly plays a structure-directing role, and ammonium chloride mainly plays a role in shortening the nucleation time. As the proportion of ammonium chloride in the ammonium chloride-piperazine system increases, the crystallinity of the AlPO4-9 zeolite molecular sieve shows a slow-fast-slow trend until the crystallinity reaches equilibrium and no longer increases. This is because when only ammonium chloride exists in the composition, the structure-directing effect is not obvious. When the molar ratio of the feed amounts of each raw material is Al2O3:P2O5:pipe:X:H2O = 1.0:1.0:0.59:0.19:100, ammonium chloride and piperazine act simultaneously, and the crystallinity reaches the highest at this time.

[0092] To explore the optimal crystallization time and optimal crystallization temperature of the reaction system, under the condition of determining the molar ratio of the feed amounts of each raw material as Al2O3:P2O5:pipe:X:H2O = 1.0:1.0:0.59:0.19:100, and calcining after crystallization reaction at 170-210 °C for 72-120 h, AlPO4-9 zeolite molecular sieve can be obtained, and the crystallinity is above 85%. Combined with Table 1 and Figure 4 、 5 it can be seen that Example 16 is the optimal reaction condition. This is because increasing the crystallization temperature can provide more kinetic energy for the crystal growth of the AlPO4-9 zeolite molecular sieve, which is conducive to the accelerated polymerization of phosphorus-oxygen tetrahedra and aluminum-oxygen tetrahedra, and then has a positive promoting effect on constructing secondary structural units and perfecting the framework structure. And an appropriate crystallization time helps to more completely establish the phosphorus-aluminum framework structure of AlPO4-9 zeolite in the liquid phase, thus improving the crystallinity.

[0093] Comparative Example 1 and Experimental Example 16 compared the crystallinity of the AlPO4-9 zeolite prepared by the prior art synthesis method and the optimal synthesis scheme of the present invention. From the crystallinity in Table 1 and Figure 6 the XRD pattern, it can be seen that under different formulations and different material ratios, the crystallinity of the AlPO4-9 zeolite increased by 12.1%, and the synthesized AlPO4-9 zeolite has a specific surface area of about 286.34 m 2 / g.

[0094] The nitrogen adsorption curve of the AlPO4-9 zeolite molecular sieve in Example 16 is as Figure 8 shown. The SEM scanning electron micrograph of the AlPO4-9 zeolite molecular sieve in Example 16 is as Figure 7 shown. From Figure 7 and Figure 8 it can be seen that the AlPO4-9 zeolite molecular sieve prepared by the method of the present invention is a flat hexagonal crystal structure with uniform size, about 75 μm.

[0095] The above is only the preferred embodiment of the present invention. It should be pointed out that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and deformations can still be made, and these improvements and deformations should also be regarded as the protection scope of the present invention.

Claims

1. A method for synthesizing highly crystalline AlPO4-9 zeolite molecular sieve without mineralizing agent, characterized in that, It includes the following steps: (1) Add an aluminum source, an inorganic structure directing agent, an organic structure directing agent, and a phosphorus source into water in sequence. After adding each raw material, stir evenly and then add other raw materials; (2) Continue stirring for several hours after all the raw materials are added; (3) Carry out a crystallization reaction on the mixture at 170 - 210 °C for 72 - 120 hours; (4) After the crystallization reaction ends, carry out suction filtration and washing, and obtain a highly crystalline AlPO4-9 zeolite molecular sieve after drying; The aluminum source is measured by Al2O3, the phosphorus source is measured by P2O5, the inorganic structure directing agent is measured by halogen element X, and the organic structure directing agent is measured by piperazine (pipe). The molar ratio of the feed amounts of each raw material is Al2O3:P2O5:pipe:X:H2O = 1.0:1.0:(0.39 - 0.59):0.19:

100.

2. The method for synthesizing highly crystalline AlPO4-9 zeolite molecular sieve without mineralizer according to claim 1, wherein The aluminum source is one of aluminum hydroxide, aluminum isopropoxide, and pseudo-boehmite.

3. The method for synthesizing high-crystallinity AlPO4-9 zeolite molecular sieve without mineralizer according to claim 1, wherein The phosphorus source is an 85% wt phosphoric acid aqueous solution.

4. The method for synthesizing high-crystallinity AlPO4-9 zeolite molecular sieve without mineralizer according to claim 1, characterized in that, The inorganic structure directing agent is one of ammonium chloride, ammonium fluoride, and sodium chloride.

5. The method for synthesizing high-crystallinity AlPO4-9 zeolite molecular sieve without mineralizer according to claim 1, wherein The molar ratio of the feed amounts of each raw material is Al2O3:P2O5:pipe:X:H2O = 1.0:1.0:0.59:(0.19 - 0.59):

100.

6. The method for synthesizing highly crystalline AlPO4-9 zeolite molecular sieve without mineralizer according to claim 1, characterized in that, The temperature of the crystallization reaction in step (3) is 190 °C; the time of the crystallization reaction is 84 hours.

7. The method for synthesizing a highly crystalline AlPO4-9 zeolite molecular sieve without a mineralizing agent according to claim 1, wherein In step (4), the washing is carried out by operating the obtained product and deionized water in a ratio of 1:10; the drying temperature is 80 °C and the time is 4 hours.

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