Flaky ERI structure phosphorus-aluminum molecular sieve as well as preparation method and application thereof

Abstract

The invention relates to the field of molecular sieves, and relates to and discloses a flaky ERI structure phosphorus-aluminum molecular sieve and a preparation method and application thereof.The crystal morphology of the molecular sieve is flaky, the crystal thickness is not larger than 1 micrometer, the radius-thickness ratio is not smaller than 5, and the molecular sieve has a pure ERI structure and is good in diffusion performance; the catalyst is especially suitable for being used as an adsorbent or a catalyst component to be applied to gas adsorption separation, synthesis gas and methanol conversion reactions, and is especially suitable for being used as a catalyst to be applied to a reaction for preparing olefin through methanol conversion under a certain pressure.

Description

Technical Field

[0001] This invention relates to the field of molecular sieves, specifically to a sheet-like ERI structured phosphorus aluminum molecular sieve, its preparation method, and its application. Background Technology

[0002] SAPO-17 (AlPO-17), a phosphorus-aluminum molecular sieve, is an ERI-type small-porous molecular sieve. This structure possesses three-dimensional eight-membered ring channels with an effective pore size of approximately 0.36 × 0.51 nm. Since the synthesis of SAPO-17 was reported in US 4440871, the synthesis of phosphorus-aluminum ERI-structured molecular sieves has become a focus of molecular sieve research.

[0003] ERI-structured aluminum phosphate molecular sieves have become a research hotspot in the synthesis of aluminum phosphate molecular sieves due to their unique pore structure and acidity. However, they are relatively sensitive to synthesis conditions, and layered or chromite-like impurities are easily generated during crystallization. Furthermore, no reports have been found of plate-like aluminum phosphate ERI-structured molecular sieves using cyclohexylamine, piperidine, or N,N,N',N'-tetramethylhexanediamine as template agents. Therefore, developing plate-like ERI-structured aluminum phosphate molecular sieves is of great practical significance for studying their properties and promoting their practical applications. Summary of the Invention

[0004] This invention provides a sheet-like ERI structured phosphorus aluminum molecular sieve. This molecular sieve has a pure ERI structure and good diffusion performance, making it particularly suitable for use as a catalyst in gas adsorption separation and methanol conversion reactions, especially in methanol conversion to olefins under certain pressure.

[0005] According to a first aspect of the present invention, the present invention provides a plate-like ERI structured phosphorus aluminum molecular sieve, wherein the molecular sieve has a plate-like crystal morphology, a crystal thickness of not more than 1 μm, and a diameter-to-thickness ratio of not less than 5.

[0006] According to a second aspect of the present invention, the present invention provides a method for preparing a sheet-like ERI structured phosphorus aluminum molecular sieve, the method comprising: (1) forming a mixture M of an aluminum source, a phosphorus source and an organic amine; (2) mixing the mixture M with a template agent to form a mixture N; and (3) aging, crystallizing, separating, washing, drying and calcining the mixture N to obtain a molecular sieve.

[0007] According to a third aspect of the present invention, the present invention provides a sheet-like ERI structured phosphorus aluminum molecular sieve prepared by the preparation method provided by the present invention.

[0008] According to a fourth aspect of the present invention, the present invention provides an application of the sheet-like ERI structured phosphorus aluminum molecular sieve of the present invention in gas adsorption separation and methanol conversion reaction.

[0009] Through the above technical solution, the sheet-like ERI-structured phosphorus-aluminum molecular sieve possesses a pure ERI structure and excellent diffusion performance; it is particularly suitable as an adsorbent or catalyst component in reactions such as carbon dioxide adsorption and separation, and methanol-to-olefins (MTO). The preparation method provided by this invention can stably synthesize the sheet-like ERI-structured phosphorus-aluminum molecular sieve described herein. The raw materials used in the preparation process are inexpensive and readily available, the operation is simple, and it is easy to scale up for industrial production. Attached Figure Description

[0010] Figure 1 This is the XRD pattern of Example 2.

[0011] Figure 2 This is the SEM image of Example 2.

[0012] Figure 3 XRD pattern of Comparative Example 1

[0013] Figure 4 SEM image of Comparative Example 1

[0014] Figure 5 XRD pattern of Comparative Example 2

[0015] Figure 6 SEM image of Comparative Example 2 Detailed Implementation

[0016] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0017] This invention provides a sheet-like ERI structured phosphorus aluminum molecular sieve, wherein the crystal morphology of the molecular sieve is sheet-like, the crystal thickness is not greater than 1 μm, and the diameter to thickness ratio is not less than 5.

[0018] The molecular sieve described in this invention has a pure ERI structure, a single crystal phase, and a small crystal thickness, which can promote the diffusion of guest molecules within the crystal.

[0019] According to a preferred embodiment of the present invention, the crystal thickness of the molecular sieve is 0.1-0.6 μm, for example, 0.15 μm, 0.2 μm, 0.25 μm, 0.3 μm, 0.35 μm, 0.4 μm, 0.45 μm, 0.5 μm, 0.55 μm, etc., and the diameter-to-thickness ratio is 5-20, for example, 8, 10, 12, 15, 18, etc. The molecular sieve of the present invention, satisfying the foregoing characteristics, exhibits superior diffusion performance.

[0020] According to a preferred embodiment of the present invention, the molecular sieve of the present invention is doped with a heteroelement, which can be silicon or a metal element. The range of metal elements that can be selected is relatively wide. The following is an illustrative description, but it does not limit the scope of the present invention. According to a preferred embodiment of the present invention, the metal element is selected from one or more of Group IIA metal elements, Group IIB metal elements, Group VIII metal elements, and rare earth metal elements.

[0021] According to a preferred embodiment of the present invention, the hetero-elements preferably include at least two of lanthanum, cerium, zinc, iron, and cobalt, and the content of each metal element in the hetero-elements is not less than 25%, preferably not less than 30%, based on the total molar amount of the hetero-element oxides. The molecular sieve prepared by the aforementioned technical solution is particularly suitable as a catalyst for the methanol-to-olefins reaction, especially for application in the methanol-to-olefins reaction under certain pressure.

[0022] According to a preferred embodiment of the present invention, the molar ratio of the impurity element (calculated as oxide) to Al2O3 in the molecular sieve is greater than 0 and not greater than 0.1, preferably 0.01-0.08:1, for example 0.02:1, 0.03:1, 0.04:1, 0.05:1, 0.06:1, 0.07:1, etc. The molecular sieve of the present invention, satisfying the foregoing characteristics, exhibits superior overall performance.

[0023] In this invention, there are no special requirements for the preparation method of molecular sieve. According to a preferred embodiment of the present invention, the preparation method includes: (1) forming a mixture M by aluminum source, phosphorus source and organic amine; (2) mixing the mixture M with a template agent to form a mixture N; (3) aging, crystallizing, separating, washing, drying and calcining the mixture N to obtain a molecular sieve.

[0024] According to a preferred embodiment of the present invention, the molar ratio of aluminum source (calculated as Al2O3), phosphorus source (calculated as P2O5), organic amine, template agent and water is 1:(0.9-1.2):(0.3-0.8):(0.8-1.2):(30-100).

[0025] The preparation method provided by this invention can stably prepare the crystalline pure plate-like ERI structure molecular sieve described in this invention.

[0026] According to a preferred embodiment of the present invention, an impurity element source is introduced during the molecular sieve preparation process. There are no special requirements regarding the order in which the impurity element source is introduced; it can be introduced in both steps (1) and (2), but is preferred to introduce it in step (1). Using the aforementioned technical solution can help adjust the crystal morphology of the molecular sieve.

[0027] In this invention, the heteroelement source can be a metal source or a silicon source. The range of metal elements in the metal source is relatively wide. The following is an illustrative description, but it does not limit the scope of the invention. According to a preferred embodiment of the invention, the metal element in the metal source is selected from one or more of Group IIA metal elements, Group IIB metal elements, Group VIII metal elements, and rare earth metal elements, and is more preferably one or more of lanthanum, cerium, zinc, iron, and cobalt.

[0028] According to a preferred embodiment of the present invention, the heteroelement source is selected from a metal source including at least two metal elements selected from lanthanum, cerium, zinc, iron and cobalt; based on the total molar amount of metal element oxides in the heteroelement source, the amount of each metal source in the heteroelement source is not less than 25%, preferably not less than 30%.

[0029] In this invention, there are no special requirements for the type of silicon source. The following is an illustrative description, but it does not limit the scope of the invention. According to a preferred embodiment of the invention, the silicon source is selected from one or more of fumed silica, silica sol and tetraethyl orthosilicate.

[0030] In this invention, the range of metal sources that can be selected is relatively wide. The following is an illustrative description, but it does not limit the scope of this invention. According to a preferred embodiment of this invention, the metal source is selected from one or more of the metal elements oxalate, nitrate, acetate, sulfate, phosphate, chloride, and sulfide.

[0031] This invention uses organic amines as crystallization aids and controls the order of addition, that is, the organic amines are added before the template agent. This can adjust the existence form of micro species in the crystallization solution and change the dominant growth direction of the crystals to a certain extent, thereby obtaining the special morphology described in this invention.

[0032] In this invention, as long as the organic amine is added before the template agent and the former is fully mixed, there are no special requirements for the interval between the two additions. Generally, the interval should not be less than 10 minutes, and can be 10-30 minutes.

[0033] In this invention, the purpose of the invention can be achieved by first forming a mixture M with an organic amine and then forming a mixture N with a template agent, in accordance with the requirements of this invention. There are no special requirements for the introduction steps or order of other materials. For example, solvent water can generally be mainly introduced in step (1) to form a uniform mixture M, and then any steps can be supplemented according to the water usage requirements.

[0034] In this invention, a wide range of organic amines can be selected. The following is an illustrative description, but it does not limit the scope of the invention. According to a preferred embodiment of the invention, the organic amine is one or more of primary, secondary, and tertiary amines with substituents having C1-C6 carbon chains, preferably one or more of diethylamine, triethylamine, n-propylamine, and di-n-propylamine. Using the aforementioned technical solution, the resulting molecular sieve can be well controlled to have a pure ERI structure crystalline phase.

[0035] In this invention, there are no special requirements for the type of template agent. Conventional template agents in this technical field can achieve the purpose of this invention. The following is an illustrative description, but it does not limit the scope of this invention. According to a preferred embodiment of this invention, the template agent is selected from cyclohexylamine and / or piperidine.

[0036] In this invention, there are no special requirements for the type of aluminum source. Commonly used aluminum sources can achieve the purpose of this invention. The following is an illustrative description, but it does not limit the scope of this invention. According to a preferred embodiment of this invention, the aluminum source is selected from one or more of aluminum isopropoxide, boehmite, and aluminum hydroxide.

[0037] In this invention, there are no special requirements for the type of phosphorus source. Conventional phosphorus sources can achieve the purpose of this invention. The following is an illustrative description, but it does not limit the scope of this invention. According to a preferred embodiment of this invention, the phosphorus source is selected from one or more of phosphoric acid, phosphorous acid, and pyrophosphoric acid.

[0038] According to a preferred embodiment of the present invention, the molar ratio of the heteroelement source (calculated as oxide) to the aluminum source (calculated as Al2O3) is less than 0.1:1, preferably 0.01-0.08:1, for example 0.02:1, 0.03:1, 0.04:1, 0.05:1, 0.06:1, 0.07:1, etc.

[0039] In this invention, there are no special requirements for the aging temperature; it can be adjusted according to actual needs. The following is an illustrative description, but it does not limit the scope of the invention. According to a preferred embodiment of the invention, the aging temperature is 30-80°C.

[0040] In this invention, there are no special requirements for the aging time; it can be adjusted according to actual needs. The following is an illustrative description, but it does not limit the scope of the invention. According to a preferred embodiment of the invention, the aging time is 6-24 hours.

[0041] In this invention, there are no special requirements for the crystallization temperature; it can be adjusted according to actual needs. The following is an illustrative description, but it does not limit the scope of the invention. According to a preferred embodiment of the invention, the crystallization temperature is 190-210°C.

[0042] In this invention, there are no special requirements for the crystallization time, which can be adjusted according to actual needs. The following is an illustrative description, but it does not limit the scope of the invention. According to a preferred embodiment of the invention, the crystallization time is 18-48 hours, preferably 16-36 hours.

[0043] This invention does not have special requirements for the crystallization method; for example, dynamic crystallization can be used.

[0044] In this invention, there are no special requirements for the location of aging and crystallization. For example, aging and crystallization can be carried out in a crystallization kettle with polytetrafluoroethylene lining.

[0045] In this invention, the separation, washing, and drying processes are well known to those skilled in the art and will not be described in detail here. For example, the separation is carried out by centrifugal separation, and the drying conditions include a temperature of 50-150°C and a time of 8-30 hours.

[0046] In this invention, there are no special requirements for the roasting temperature; it can be adjusted according to actual needs. The following is an illustrative description, but it does not limit the scope of the invention. According to a preferred embodiment of the invention, the roasting temperature is 450-650°C, and more preferably 500-600°C.

[0047] In this invention, there are no special requirements for the roasting time, which can be adjusted according to actual needs. The following is an illustrative description, but it does not limit the scope of the invention. According to a preferred embodiment of the invention, the roasting time is 3-12 hours, and more preferably 4-6 hours.

[0048] The pure-phase ERI structure phosphorus aluminum molecular sieve of the present invention can be prepared by satisfying the aforementioned methods. Preferably, the molecular sieve has a plate-like crystal morphology, a crystal thickness of not more than 1 μm, and a diameter-to-thickness ratio of not less than 5.

[0049] According to a preferred embodiment of the present invention, the molecular sieve has a crystal thickness of 0.1-0.6 μm and a diameter-to-thickness ratio of 5-20.

[0050] According to a preferred embodiment of the present invention, the molecular sieve is doped with heterogeneous elements.

[0051] According to a preferred embodiment of the present invention, the heteroelement includes silicon and / or a metal element; the metal element is selected from one or more of Group IIA metals, Group IIB metals, Group VIII metals, and rare earth metals.

[0052] According to a preferred embodiment of the present invention, the heteroelement includes at least two of lanthanum, cerium, zinc, iron, and cobalt; based on the total molar amount of the heteroelement oxides, the content of each metal element in the heteroelement is not less than 25%, preferably not less than 30%.

[0053] According to a preferred embodiment of the present invention, the molar ratio of the heteroelement to Al, calculated as oxide, is greater than 0 and not greater than 0.1, preferably 0.01-0.08:1.

[0054] The sheet-like ERI structured phosphorus aluminum molecular sieve prepared by this invention has a pure ERI structure and good diffusion performance, making it particularly suitable for use as a catalyst in gas adsorption separation and methanol conversion reactions, especially in methanol conversion to olefins under certain pressure.

[0055] The present invention will be described in detail below through embodiments.

[0056] In the following embodiments,

[0057] The crystal structure of the molecular sieve was analyzed using a Panalytical XPERPRO X-ray powder diffractometer, with CuKα radiation source. Nickel filter, 2θ scanning range 3–50°, operating voltage 40 kV, current 40 mA. The microstructure of the molecular sieve was measured using an S-4800II field emission scanning electron microscope.

[0058] The crystal thickness of the molecular sieve was calculated by randomly measuring the average thickness of the crystals in the field of view of SEM images, repeating this operation 5 times, and calculating the average of the sum of the 5 averages.

[0059] The ratio of crystal diameter to thickness of molecular sieve (hereinafter referred to as diameter-to-thickness ratio) is obtained by directly calculating the ratio of diameter and thickness measured multiple times.

[0060] The content of impurities in the molecular sieve in the crystallization solution and the molar ratio of impurities (calculated as oxides) to Al2O3 were obtained through feeding calculations. In addition, the concentration of the impurity source used was diluted to a certain extent to facilitate use and make it more uniformly dispersed.

[0061] Aluminum isopropoxide, phosphoric acid (85%), cyclohexylamine, triethylamine, diethylamine, dipropylamine, and tripropylamine are commercially available products from China National Pharmaceutical Group. Boehmite is GA-381 produced by Jiangsu Sanji Industrial Co., Ltd., with a mass content of 70% based on alumina (Al2O3). Silica sol is HS-Ludox-40% (Sigma-Aldrich; can be diluted independently), and deionized water is used for self-preparation.

[0062] The drying conditions were: temperature 110℃, drying time 10h; the calcination conditions were: temperature 550℃, time 6h.

[0063]

Example 1

[0064] 6.7 g of pseudoboehmite was weighed and added to water. After thorough stirring, phosphoric acid was added and mixed thoroughly. This mixture was then labeled as Mixture I. Next, silica sol (4% by mass) was added to Mixture I and mixed thoroughly, resulting in Mixture II. Triethylamine (TEA) was added to Mixture II to obtain Mixture M. After 20 min, cyclohexylamine (CHA) was added and mixed thoroughly to obtain Mixture N. The molar ratio of the materials in Mixture N was: 0.06SiO2:1.0Al2O3:1.1P2O5:0.5TEA:1CHA:50H2O. After thorough mixing, the mixture was transferred to a crystallization vessel and placed in a homogeneous reactor. It was aged at 30°C for 16 h, then heated to 200°C and crystallized at this temperature for 36 h. The resulting molecular sieve was separated, washed, dried, and calcined. The molecular sieve had a crystal thickness of approximately 0.2 μm and an aspect ratio of approximately 15. Its XRD pattern is shown below. Figure 1 SEM image as follows Figure 2 As shown, the obtained molecular sieve is a pure-phase ERI structure molecular sieve with a plate-like morphology.

[0065]

Example 2

[0066] 18.6 g of aluminum isopropoxide was weighed and added to water. After thorough stirring, phosphoric acid was added and mixed thoroughly. This mixture was then labeled as Mixture I. Silica sol (4% by mass) was then added to Mixture I and mixed thoroughly, resulting in Mixture II. Triethylamine (TEA) was added to Mixture II to obtain Mixture M. After 10 minutes, cyclohexylamine (CHA) was added and mixed thoroughly to obtain Mixture N. The molar ratio of the materials in Mixture N was: 0.06 SiO2:1.0 Al2O3:1.1 P2O5:0.5 TEA:1 CHA:50 H2O. After thorough mixing, the mixture was transferred to a crystallization vessel and placed in a homogeneous reactor. It was aged at 30°C for 16 hours, then heated to 200°C and crystallized at this temperature for 36 hours. The resulting molecular sieve was separated, washed, dried, and calcined. The molecular sieve had a crystal thickness of approximately 0.3 μm and an aspect ratio of approximately 8. Its XRD pattern was similar to... Figure 1 Similarly, SEM images and Figure 2 similar.

[0067]

Example 3

[0068] 6.7g of pseudoboehmite was weighed and added to water. After thorough stirring, phosphoric acid was added and mixed thoroughly. This mixture was then labeled as Mixture I. Silica sol (4% by mass) was then added to Mixture I and mixed thoroughly, resulting in Mixture II. Triethylamine (TEA) was added to Mixture II to obtain Mixture M. After 10 minutes, cyclohexylamine (CHA) was added and mixed thoroughly to obtain Mixture N. The molar ratio of the materials in Mixture N was: 0.03SiO2:1.0Al2O3:1.1P2O5:0.5TEA:1CHA:35H2O. After thorough mixing, the mixture was transferred to a crystallization vessel and placed in a homogeneous reactor. It was aged at 30℃ for 16 hours, then heated to 200℃ and crystallized at this temperature for 36 hours. The resulting molecular sieve was separated, washed, dried, and calcined. The molecular sieve had a crystal thickness of approximately 0.25μm and an aspect ratio of approximately 13. Its XRD pattern was similar to... Figure 1 Similarly, SEM images and Figure 2 similar.

[0069]

Example 4

[0070] 6.7 g of pseudoboehmite was weighed and added to water. After thorough stirring, phosphoric acid was added and mixed thoroughly. This mixture was then labeled as mixture I. Triethylamine (TEA) was added to mixture I to obtain mixture M. After 30 min, cyclohexylamine (CHA) was added and mixed thoroughly to obtain mixture N. The molar ratio of the materials in mixture N was: 1.0 Al₂O₃: 1.1 P₂O₅: 0.5 TEA: 1 CHA: 35 H₂O. After thorough stirring, the mixture was transferred to a crystallization vessel and placed in a homogeneous reactor. It was aged at 30 °C for 16 h, then heated to 200 °C and crystallized at this temperature for 36 h. The resulting molecular sieve was separated, washed, dried, and calcined. The molecular sieve had a crystal thickness of approximately 0.3 μm and an aspect ratio of approximately 10. Its XRD pattern was similar to... Figure 1 Similarly, SEM images and Figure 2 similar.

[0071]

Example 5

[0072] 6.7g of pseudoboehmite was weighed and added to water. After thorough stirring, phosphoric acid was added and mixed thoroughly. This mixture was then labeled as Mixture I. Silica sol (40% by mass) was added to Mixture I and mixed thoroughly, resulting in Mixture II. Triethylamine (TEA) was added to Mixture II to obtain Mixture M. After 20 minutes, cyclohexylamine (CHA) was added and mixed thoroughly to obtain Mixture N. The molar ratio of the materials in Mixture N was: 0.1SiO2:1.0Al2O3:1.0P2O5:0.78TEA:1.0CHA:80H2O. After thorough mixing, the mixture was transferred to a crystallization vessel and placed in a homogeneous reactor. It was aged at 30℃ for 16 hours, then heated to 200℃ and crystallized at this temperature for 36 hours. The resulting molecular sieve was separated, washed, dried, and calcined. The molecular sieve had a crystal thickness of approximately 0.44μm and an aspect ratio of approximately 6. Its XRD pattern was similar to... Figure 1 Similarly, SEM images and Figure 2 similar.

[0073]

Example 6

[0074] 6.7g of pseudoboehmite was weighed and added to water. After thorough stirring, phosphoric acid was added and mixed thoroughly. This mixture was then labeled as Mixture I. Silica sol (40% by mass) was added to Mixture I and mixed thoroughly, resulting in Mixture II. Triethylamine (TEA) was added to Mixture II to obtain Mixture M. After 30 minutes, piperidine (PI) was added and mixed thoroughly to obtain Mixture N. The molar ratio of the materials in Mixture N was: 0.08SiO2:1.0Al2O3:1.0P2O5:0.5TEA:1.0PI:80H2O. After thorough mixing, the mixture was transferred to a crystallization vessel and placed in a homogeneous reactor. It was aged at 60℃ for 12 hours, then heated to 200℃ and crystallized at this temperature for 36 hours. The resulting molecular sieve was separated, washed, dried, and calcined. The molecular sieve had a crystal thickness of approximately 0.35μm and an aspect ratio of approximately 10. Its XRD pattern was similar to... Figure 1 Similarly, SEM images and Figure 2 similar.

[0075]

Example 7

[0076] 6.7g of pseudoboehmite was weighed and added to water. After thorough stirring, phosphoric acid was added and mixed thoroughly. This mixture was then labeled as Mixture I. Silica sol (40% by mass) was added to Mixture I and mixed thoroughly, resulting in Mixture II. Diethylamine (DEA) was added to Mixture II to obtain Mixture M. After 20 minutes, piperidine (PI) was added and mixed thoroughly to obtain Mixture N. The molar ratio of the materials in Mixture N was: 0.08SiO2:1.0Al2O3:1.0P2O5:0.5DEA:1.0PI:90H2O. After thorough mixing, the mixture was transferred to a crystallization vessel and placed in a homogeneous reactor. It was aged at 30℃ for 20 hours, then heated to 210℃ and crystallized at this temperature for 24 hours. The resulting molecular sieve was separated, washed, dried, and calcined. The molecular sieve had a crystal thickness of approximately 0.25μm and an aspect ratio of approximately 12. Its XRD pattern was similar to... Figure 1 Similarly, SEM images and Figure 2 similar.

[0077]

Example 8

[0078] 6.7g of pseudoboehmite was weighed and added to water. After thorough stirring, phosphoric acid was added and mixed thoroughly. This mixture was then labeled as Mixture I. Silica sol (40% by mass) was then added to Mixture I and mixed thoroughly, resulting in Mixture II. Next, n-propylamine (n-Pro) was added to Mixture II sequentially to obtain Mixture M. After 30 minutes, piperidine (PI) was added and mixed thoroughly to obtain Mixture N. The molar ratio of the materials in Mixture N was: 0.08SiO2:1.0Al2O3:1.0P2O5:0.5(n-Pro):1.0PI:90H2O. After thorough mixing, the mixture was transferred to a crystallization vessel and placed in a homogeneous reactor. It was aged at 30℃ for 20 hours, then heated to 210℃ and crystallized at this temperature for 24 hours. The resulting molecular sieve was separated, washed, dried, and calcined. The molecular sieve had a crystal thickness of approximately 0.3μm and an aspect ratio of approximately 11. Its XRD pattern was similar to... Figure 1 Similarly, SEM images and Figure 2 similar.

[0079]

Example 9

[0080] 6.7g of pseudoboehmite was weighed and added to water. After thorough stirring, phosphoric acid was added and mixed thoroughly. This mixture was then labeled as mixture I. Fumed silica was added to mixture I and mixed thoroughly, resulting in mixture II. Di-n-Pro was added to mixture II to obtain mixture M. After 30 minutes, piperidine (PID) was added and mixed thoroughly to obtain mixture N. The molar ratio of the materials in mixture N was: 0.08SiO2:1.0Al2O3:1.0P2O5:0.2(Di-n-Pro):1.0PID:90H2O. After thorough mixing, the mixture was transferred to a crystallization vessel and placed in a homogeneous reactor. The mixture was aged at 80℃ for 8 hours, then heated to 210℃ and crystallized for 18 hours. The resulting molecular sieve was separated, washed, dried, and calcined. The molecular sieve had a crystal thickness of approximately 0.25μm and an aspect ratio of approximately 12. Its XRD pattern was similar to... Figure 1 Similarly, SEM images and Figure 2 similar.

[0081]

Example 10

[0082] 6.7g of pseudoboehmite was weighed and added to water. After thorough stirring, phosphoric acid was added and mixed thoroughly. This mixture was then labeled as Mixture I. Zinc nitrate solution (5% by mass) was added to Mixture I and mixed thoroughly, resulting in Mixture II. Triethylamine (TEA) was added to Mixture II to obtain Mixture M. After 20 minutes, cyclohexylamine (CHA) was added and mixed thoroughly to obtain Mixture N. The molar ratio of the materials in Mixture N was: 0.05ZnO:1.0Al2O3:1.1P2O5:0.5TEA:1CHA:70H2O. After thorough mixing, the mixture was transferred to a crystallization vessel and placed in a homogeneous reactor. It was aged at 30℃ for 12 hours, then heated to 200℃ and crystallized at this temperature for 24 hours. The resulting molecular sieve was separated, washed, dried, and calcined. The molecular sieve had a crystal thickness of approximately 0.2μm and an aspect ratio of approximately 13. Its XRD pattern was similar to... Figure 1 Similarly, SEM images and Figure 2 similar.

[0083]

Example 11

[0084] Following the method of Example 10, except that the added impurity element source was cerium nitrate solution, a molecular sieve was prepared. The crystal thickness of this molecular sieve was approximately 0.4 μm, and the aspect ratio was approximately 8. Its XRD pattern was similar to... Figure 1 Similarly, SEM images and Figure 2 similar.

[0085]

Example 12

[0086] Following the method of Example 10, except that the added impurity element source was lanthanum nitrate solution, a molecular sieve was prepared. The crystal thickness of this molecular sieve was approximately 0.38 μm, and the aspect ratio was approximately 9. Its XRD pattern was similar to... Figure 1 Similarly, SEM images and Figure 2 similar.

[0087]

Example 13

[0088] Following the method of Example 10, except that the added impurity element source is cobalt nitrate solution, a molecular sieve is prepared with a crystal thickness of about 0.28 μm and an aspect ratio of about 11.

[0089]

Example 14

[0090] Following the method of Example 10, except that the added impurity element source was ferrous sulfate solution, a molecular sieve was prepared. The crystal thickness of this molecular sieve was approximately 0.31 μm, and the aspect ratio was approximately 10. Its XRD pattern was similar to... Figure 1 Similarly, SEM images and Figure 2 similar.

[0091]

Example 15

[0092] Following the method of Example 10, except that the added impurity element sources were cobalt nitrate solution and zinc nitrate solution, with a feed ratio of 0.03CoO:0.02ZnO:1Al2O3, a molecular sieve was prepared. The molecular sieve had a crystal thickness of approximately 0.22 μm and an aspect ratio of approximately 12. Its XRD pattern is similar to... Figure 1 Similarly, SEM images and Figure 2 similar.

[0093]

Example 16

[0094] Following the method of Example 10, except that the zinc nitrate solution was added after cyclohexylamine to prepare a molecular sieve with a crystal thickness of approximately 0.52 μm and an aspect ratio of approximately 6. Its XRD pattern is similar to... Figure 1 Similarly, SEM images and Figure 2 similar.

[0095] Comparative Example 1

[0096] 6.7 g of pseudoboehmite was weighed and added to water. After thorough stirring, phosphoric acid was added and mixed thoroughly. This mixture was then labeled as Mixture I. Next, silica sol (4% by mass) was added to Mixture I and mixed thoroughly, resulting in Mixture II. Cyclohexylamine (CHA) was added to Mixture II and mixed thoroughly, achieving a molar ratio of 0.06SiO2:1.0Al2O3:1.1P2O5:1.0CHA:50H2O. After thorough mixing, the mixture was transferred to a crystallization vessel and placed in a homogeneous reactor. It was aged at 30°C for 16 h, then heated to 200°C and crystallized for 36 h. The crystals were then separated, washed, dried, and calcined to obtain SAPO-17 molecular sieve containing impurities. Its XRD pattern is shown below. Figure 3 As shown, SEM Figure 4 As shown.

[0097] Comparative Example 2

[0098] 6.7 g of pseudoboehmite was weighed and added to water. After thorough stirring, phosphoric acid was added and mixed thoroughly. This mixture was then labeled as Mixture I. Next, silica sol (4% by mass) was added to Mixture I and mixed thoroughly, resulting in Mixture II. Cyclohexylamine (CHA) was then added to Mixture II and mixed thoroughly, resulting in the following molar ratio: 0.06SiO2:1.0Al2O3:1.1P2O5:1.5CHA:50H2O. After thorough mixing, the mixture was transferred to a crystallization vessel and placed in a homogeneous reactor. It was aged at 30°C for 16 h, then heated to 200°C and crystallized for 36 h. The crystals were then separated, washed, dried, and calcined to obtain SAPO-17 molecular sieve containing an impurity phase (a plate-like impurity phase exhibiting low-angle diffraction peaks in XRD). Its XRD pattern is shown below. Figure 5 As shown, SEM Figure 6 As shown.

[0099] Chemical evaluation method: The products prepared in the examples and comparative examples were used as reaction catalysts. After the catalyst was tableted, the 20-40 mesh fraction was sieved. Fixed bed, tube diameter 1 cm, 430℃, space velocity 2 h⁻¹ -1 The gas was pure methanol; nitrogen was used as the carrier gas and the pressure of the apparatus was kept constant at 0.8 MPa, with a nitrogen flow rate of 10 ml / min; the composition of the products was analyzed online using a Shimadzu GC-2014 gas chromatograph equipped with a Plot-Q column, FID detection, and the content of each product was calculated by area normalization method.

[0100] In this chemical evaluation, a higher total selectivity for ethylene and propylene, and a higher ratio of ethylene to propylene, indicate better molecular sieve performance.

[0101] The selectivity of ethylene is calculated as follows:

[0102] Ethylene selectivity = area of ​​the ethylene peak / sum of the areas of all products; that is, S乙烯 / ΣS 产物 The selectivity calculation method for ×100% propylene is as follows:

[0103] The selectivity of propylene = the area of ​​the propylene peak / the sum of the areas of all products; that is, S. 丙烯 / ΣS 产物 ×100% Table 1

[0104]

[0105] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A sheet-like ERI structured phosphorus aluminum molecular sieve, characterized in that, The molecular sieve has a plate-like crystal morphology with a thickness of no more than 1 μm and a diameter-to-thickness ratio of no less than 5.

2. The molecular sieve according to claim 1, wherein, The molecular sieve has a crystal thickness of 0.1-0.6 μm; a diameter-to-thickness ratio of 5-20; and / or The molecular sieve is doped with impurity elements; Preferably, The hetero-elements include silicon and / or metallic elements; the metallic elements are selected from one or more of Group IIA metallic elements, Group IIB metallic elements, Group VIII metallic elements, and rare earth metallic elements. Preferably, the heteroelement includes at least two of lanthanum, cerium, zinc, iron, and cobalt; based on the total molar amount of the heteroelement oxides, the content of each metal element in the heteroelement is not less than 25%, preferably not less than 30%.

3. The molecular sieve according to claim 1 or 2, wherein, Based on oxides, the molar ratio of the heteroelement to Al is greater than 0 and not greater than 0.1, preferably 0.01-0.08:

1.

4. A method for preparing a sheet-like ERI structured phosphorus aluminum molecular sieve, characterized in that, The preparation method includes: (1) Form a mixture M from aluminum source, phosphorus source and organic amine; (2) Mix the mixture M with the template agent to form the mixture N; (3) The mixture N is aged, crystallized, separated, washed, dried and calcined to obtain molecular sieves; Preferably, the molar ratio of aluminum source (calculated as Al2O3), phosphorus source (calculated as P2O5), organic amine, template agent and water is 1:(0.9-1.2):(0.3-0.8):(0.8-1.2):(30-100).

5. The preparation method according to claim 4, wherein, Step (1) and / or step (2) are performed in the presence of a heterogeneous element source, preferably step (1) is performed in the presence of a heterogeneous element source; Preferably, The heteroelement source is selected from a metal source and / or a silicon source; wherein, the metal element in the metal source is selected from one or more of Group IIA metal elements, Group IIB metal elements, Group VIII metal elements, and rare earth metal elements, preferably one or more of lanthanum, cerium, zinc, iron, and cobalt; Preferably, the heteroelement source is selected from a metal source including at least two metal elements selected from lanthanum, cerium, zinc, iron, and cobalt; based on the total molar amount of metal element oxides in the heteroelement source, the amount of each metal source in the heteroelement source is not less than 25%, preferably not less than 30%; Preferably, the silicon source is selected from one or more of fumed silica, silica sol, and tetraethyl orthosilicate; Preferably, the metal source is selected from one or more of the following metal elements: oxalate, nitrate, acetate, sulfate, phosphate, and chloride.

6. The preparation method according to claim 4 or 5, wherein, The organic amine is one or more of primary, secondary, and tertiary amines with substituents having C1-C6 carbon chains, preferably one or more of diethylamine, triethylamine, n-propylamine, and di-n-propylamine; and / or The template agent is selected from cyclohexylamine and / or piperidine; and / or The aluminum source is selected from one or more of aluminum isopropoxide, boehmite, and aluminum hydroxide; and / or The phosphorus source is selected from one or more of phosphoric acid, phosphorous acid, and pyrophosphoric acid.

7. The preparation method according to claim 5, wherein, The molar ratio of the heteroelement source (calculated as oxide) to the aluminum source (calculated as Al2O3) is below 0.1:1, preferably 0.01-0.08:

1.

8. The preparation method according to any one of claims 4-7, wherein, The aging conditions include: a temperature of 30-80℃; and / or a time of 6-24 hours; and / or The crystallization conditions include: a temperature of 190-210℃; and / or a time of 18-48h, preferably 16-36h; and / or The calcination conditions include: a temperature of 450-650℃, preferably 500-600℃; and / or a time of 3-12h, preferably 4-6h.

9. The sheet-like ERI structured phosphorus aluminate molecular sieve prepared by the preparation method according to any one of claims 4-8 is preferably characterized by the following: the crystal morphology of the molecular sieve is sheet-like, the crystal thickness is not greater than 1 μm, and the ratio of diameter to thickness is not less than 5. Preferably, the molecular sieve has a crystal thickness of 0.1-0.6 μm and a diameter-to-thickness ratio of 5-20. Preferably, the molecular sieve is doped with heterogeneous elements; Preferably, the heteroelement includes silicon and / or a metallic element; the metallic element is selected from one or more of Group IIA metallic elements, Group IIB metallic elements, Group VIII metallic elements, and rare earth metallic elements. Preferably, the heteroelement includes at least two of lanthanum, cerium, zinc, iron, and cobalt; based on the total molar amount of the heteroelement oxides, the content of each metal element in the heteroelement is not less than 25%, preferably not less than 30%. Preferably, the molar ratio of the heteroelement to Al, calculated as oxide, is greater than 0 and not greater than 0.1, and more preferably 0.01-0.08:

1.

10. The application of the sheet-like ERI structured phosphorus aluminum molecular sieve according to any one of claims 1-3 and 9 in gas adsorption separation and methanol-to-olefins conversion reaction.

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