Organic templating agent piperidinium derivative for preparing molecular sieve, and use thereof

Abstract

The present invention belongs to the technical field of molecular sieve materials, and particularly relates to an organic templating agent piperidinium derivative for preparing a molecular sieve, and the use thereof. The organic templating agent piperidinium derivative has high hydrothermal stability, is not prone to decomposing during a molecular sieve preparation process and has a high utilization rate. Using the organic templating agent piperidinium derivative for preparing an SSZ-39 molecular sieve can significantly improve the yield of the SSZ-39 molecular sieve, and further reduces the amount of the organic templating agent piperidinium derivative, thereby reducing the production cost of the molecular sieve. In addition, the preparation process is simple, and there is less pollution to the environment, which are beneficial for the industrial production and use of the molecular sieve. The structure of the organic templating agent piperidinium derivative is as represented by general formula I.

Description

An organic template piperidinium derivative for preparing molecular sieves and its application

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims the benefit of Chinese Application No. 202311518187X, filed on November 15, 2023. Said application No. 202311518187X is hereby incorporated by reference in its entirety. Technical Field

[0003] The invention belongs to the technical field of molecular sieve materials, and particularly relates to an organic template agent piperidinium derivative for preparing molecular sieves and application thereof. Background Art

[0004] As a typical porous material, molecular sieve has a large specific surface area, excellent pore shape selectivity and good adsorption performance, and is widely used in adsorption, catalysis and ion exchange.

[0005] Currently, air pollution primarily comes from industrial flue gas emissions and automobile exhaust. To reduce pollutant emissions, countries around the world are actively developing flue gas denitrification technologies. Industrially, there are two flue gas denitrification technologies: one uses molecular sieves to reduce pollutants in the atmosphere at a certain temperature, and the other uses molecular sieves to directly adsorb solid particles and certain specific harmful gases in the atmosphere. Currently, the primary treatment method is the selective catalytic reduction of NH3 (NH3-SCR). The key to this technology lies in the catalytic performance of the molecular sieve material, with CHA and AEI molecular sieves offering the most outstanding performance. SSZ-39 molecular sieve is an AEI molecular sieve, composed of AlO4 and SiO4 tetrahedra connected end-to-end by oxygen atoms, arranged in an orderly fashion into double six-membered rings (D6R). These double six-membered rings are connected by some four-membered rings, forming a three-dimensional pore structure with a maximum of eight-membered rings. Compared to CHA molecular sieves, it offers smaller pores, higher catalytic activity, improved high-temperature performance, and a longer life. However, the preparation method of SSZ-39 molecular sieve is relatively complicated, with high cost and low yield, which is not conducive to large-scale application and production.

[0006] In molecular sieve synthesis, templates play four roles: template, structure-directing, space-filling, and balancing framework charge, enabling the molecular sieve to form a stable structure. Templates play a crucial role in molecular sieve synthesis. Therefore, developing a new template is of great significance for the preparation of molecular sieves, especially SSZ-39 molecular sieves.

[0007] Summary of the Invention

[0008] The present invention provides a piperidinium derivative as an organic template for preparing molecular sieves and its application. The piperidinium derivative exhibits high hydrothermal stability, is resistant to decomposition during the molecular sieve preparation process, and has a high utilization rate. This reduces the amount of the organic template, lowers the production cost of the molecular sieve, and improves the yield of the molecular sieve. Furthermore, the reduced amount of template also reduces the amount of harmful gases generated during the high-temperature calcination process, resulting in less environmental pollution and facilitating the industrial production and application of molecular sieves.

[0009] Specifically, the present invention is achieved through the following technical solutions:

[0010] In a first aspect, the present invention provides a piperidinium derivative as an organic template for preparing a molecular sieve, the structure of which is shown in Formula I:

[0011] Wherein, R1 and R2 are each independently selected from methyl, ethyl, propyl, butyl, pentyl, and hexyl;

[0012] A1, A2, A3, A4, and A5 are each independently selected from hydrogen, methyl, ethyl, propyl, butyl, pentyl, hexyl, methoxy, ethoxy, propoxy, butoxy, pentyloxy, and hexyl, wherein at least one of A1, A2, A3, A4, and A5 is selected from methyl, ethyl, propyl, butyl, pentyl, and hexyl, and at least one is selected from methoxy, ethoxy, propoxy, butoxy, pentyloxy, and hexyl.

[0013] Preferably, R1 and R2 are each independently selected from methyl, ethyl, and propyl.

[0014] Preferably, A1, A2, A3, A4, and A5 are each independently selected from hydrogen, methyl, ethyl, propyl, methoxy, ethoxy, and propoxy, wherein at least one of A1, A2, A3, A4, and A5 is selected from methyl, ethyl, and propyl, and at least one is selected from methoxy, ethoxy, and propoxy.

[0015] Furthermore, the present invention preferably uses an organic template piperidinium derivative represented by the following structural formula:

[0016] Furthermore, the present invention also provides a method for preparing the piperidinium derivative represented by general formula I, comprising the following steps:

[0017] (1) In an autoclave, a mixture of methanol and water is used as the reaction solvent. Under a nitrogen atmosphere, the piperidine derivative represented by the general formula II and a dialkyl carbonate are reacted. The reaction is carried out to obtain the piperidinium salt represented by the general formula III;

[0018] (2) Adding the piperidinium salt of formula III prepared in step (1) to deionized water, adding lithium hydroxide, and then adding calcium hydroxide to react to obtain the piperidinium derivative of formula I. The synthesis route is as follows:

[0019] wherein R1, R2, A1, A2, A3, A4, and A5 are as defined in the above general formula I.

[0020] In a second aspect, the present invention provides a use of a piperidinium derivative represented by general formula I as an organic template in the preparation of a molecular sieve, wherein the molecular sieve is SSZ-39 molecular sieve.

[0021] In a third aspect, the present invention provides a method for preparing SSZ-39 molecular sieve, wherein the method uses a piperidinium derivative represented by general formula I as an organic template.

[0022] In the preparation method of the above SSZ-39 molecular sieve, the aluminum source is Y molecular sieve, the silicon source is 30% silica sol, and the seed crystal is commercially available SSZ-39 molecular sieve.

[0023] The specific preparation method includes: first mixing Y molecular sieve with deionized water, stirring, and then sequentially adding an aqueous solution of an organic template agent piperidinium derivative represented by general formula I, an alkali source, a silicon source and seed crystals, heating to 30-70°C, and stirring for 2-4 hours; then pouring the materials into an autoclave, sealing and heating to 160-200°C, hydrothermally reacting for 45-50 hours, taking out the materials, standing, filtering, washing the filter cake with deionized water until neutral, then dehydrating and drying, and then placing in a muffle furnace, calcining at 300-400°C, and washing with water to obtain a new SSZ-39 molecular sieve.

[0024] In a fourth aspect, the present invention provides an SSZ-39 molecular sieve prepared by the preparation method of the SSZ-39 molecular sieve.

[0025] Compared with the prior art, the present invention has the following beneficial effects:

[0026] (1) The present invention provides a piperidinium derivative as an organic template, which has high hydrothermal stability, is not easily decomposed during the preparation of molecular sieves, and has a high utilization rate. Therefore, the amount of the organic template used is reduced, and the production cost of the molecular sieve is reduced. Secondly, the reduced amount of the organic template also reduces the amount of harmful gases generated during the high-temperature calcination process, resulting in less pollution to the environment.

[0027] (2) The present invention provides an organic template piperidinium derivative, which has both alkoxy substituents and alkyl substituents, so that the organic template has good structural matching with the SSZ-39 molecular sieve cage, which is beneficial to the formation of crystals during the crystallization process of the SSZ-39 molecular sieve, accelerates the crystallization efficiency of the SSZ-39 molecular sieve, shortens the crystallization time, and the synthesized SSZ-39 molecular sieve has a high yield and high crystallinity.

[0028] (3) The present invention provides a method for preparing an organic template piperidinium derivative. The preparation method is simple to operate, has mild reaction conditions, does not use expensive chemical raw materials, has low production costs, and is conducive to the industrial production and application of molecular sieves. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the embodiments of the present invention, they are used to explain the present invention and do not constitute a limitation of the present invention. In the accompanying drawings:

[0030] FIG1 is a scanning electron microscope image of the SSZ-39 molecular sieve prepared in Application Example 1 of the present invention.

[0031] FIG2 is an XRD spectrum of the SSZ-39 molecular sieve prepared in Application Example 1 of the present invention. DETAILED DESCRIPTION

[0032] The embodiments of the present invention are described in detail below. The embodiments are given to better illustrate the contents of the present invention and are only used to explain the present invention, and should not be understood as limiting the present invention.

[0033] If no specific techniques or conditions are specified in the examples, the experiments were carried out according to the techniques or conditions described in the literature in the field or according to the product instructions. If no manufacturer is specified for the reagents or instruments used, they are all conventional products that can be purchased through regular channels.

[0034] Example 1: Organic template piperidinium derivative P1

[0035] The preparation method of the piperidinium derivative P1 comprises the following steps:

[0036] (1) In a 500 ml autoclave, 14.3 g of 1,3-dimethyl-5-methoxypiperidine P1-0 (of which the trans isomer content is 28.89%), 10 g of dimethyl carbonate, 20 ml of methanol, and 2 ml of water were added. The autoclave was sealed and replaced with nitrogen three times. The atmosphere was then filled with nitrogen to 1.2 MPa. The temperature was raised to 120° C. and the reaction was carried out for 6 hours. The temperature was then lowered, and the reaction solution was concentrated to remove methanol and water, thereby obtaining a viscous substance containing the intermediate piperidinium salt P1-1. The product was directly subjected to the next step without purification.

[0037] (2) The viscous substance containing the intermediate piperidinium salt P1-1 prepared in step (1) was added to 50 ml of deionized water, 0.25 g of lithium hydroxide was added, and then 2.1 g of calcium hydroxide was added. The temperature was raised to 60° C. and kept warm for 6 h. The unreacted calcium hydroxide and the generated calcium carbonate were filtered out, and the excess water and methanol were evaporated to obtain 55 g of an aqueous solution of the organic template piperidinium derivative P1. The solution was calibrated with 0.1 mol / L hydrochloric acid solution to obtain a mass concentration of 26.2%. The hydroxide content in the organic template was 2.5%.

[0038] To obtain pure piperidinium derivative P1, the following experiment was performed:

[0039] 5 g of the aqueous solution of the piperidinium derivative P1 obtained above was extracted with 10 ml of ethyl acetate. The ethyl acetate layer was dried over anhydrous sodium sulfate, the desiccant was filtered off, and the mixture was allowed to evaporate slowly under nitrogen until crystals appeared. The crystals were filtered and dried in vacuo to obtain pure piperidinium derivative P1. The elemental analysis results are as follows:

[0040] Theoretical value (%): C, 68.30; H, 12.74; N, 8.85, measured value (%): C, 68.32; H, 12.73; N, 8.83.

[0041] Example 2: Organic template piperidinium derivative P2

[0042] The preparation method of the piperidinium derivative P2 comprises the following steps:

[0043] Referring to the synthesis method of the piperidinium derivative P1 in Example 1, except that the raw material 1,3-dimethyl-5-methoxypiperidine P1-0 was replaced with 1,2-dimethyl-3-methoxypiperidine P2-0 (wherein the trans isomer content was 26.17%), 56 g of an aqueous solution of the organic template piperidinium derivative P2 was obtained, which was calibrated with 0.1 mol / L hydrochloric acid solution to obtain a mass concentration of 25.8%, and the hydroxide content in the organic template was 2.5%.

[0044] Example 3: Organic template piperidinium derivative P3

[0045] The preparation method of the piperidinium derivative P3 comprises the following steps:

[0046] Referring to the synthesis method of the piperidinium derivative P1 in Example 1, except that the dimethyl carbonate was replaced with diethyl carbonate, 61 g of an aqueous solution of the organic template piperidinium derivative P3 was obtained, which was calibrated with 0.1 mol / L hydrochloric acid solution to obtain a mass concentration of 26.6%. The hydroxide content in the organic template was 2.4%.

[0047] Example 4: Organic template piperidinium derivative P4

[0048] The preparation method of the piperidinium derivative P4 comprises the following steps:

[0049] Referring to the synthesis method of the piperidinium derivative P2 in Example 2, except that the dimethyl carbonate was replaced with diethyl carbonate, 61 g of an aqueous solution of the organic template piperidinium derivative P4 was obtained, which was calibrated with 0.1 mol / L hydrochloric acid solution to obtain a mass concentration of 27.8%, and the hydroxide content in the organic template was 2.5%.

[0050] Comparative Example 1: Organic template D1 without alkyl substituents on the piperidinium ring carbon atom

[0051] The preparation method of an organic template D1 having no alkyl substituent on a piperidinium ring carbon atom comprises the following steps:

[0052] Referring to the synthesis method of the piperidinium derivative P1 in Example 1, except that the raw material 1,3-dimethyl-5-methoxypiperidine P1-0 was replaced with 1-methyl-3,5-dimethoxypiperidine D1-0 (wherein the trans isomer content was 31.19%), 48 g of an aqueous solution of an organic template D1 having no alkyl substituent on the piperidinium ring carbon atom was obtained, which was calibrated with 0.1 mol / L hydrochloric acid solution to have a mass concentration of 27.1%, and the hydroxide content in the organic template was 2.4%.

[0053] Comparative Example 2: Organic template D2 without alkyl substituents on the piperidinium ring carbon atom

[0054] The preparation method of an organic template D2 having no alkyl substituent on a piperidinium ring carbon atom comprises the following steps:

[0055] Referring to the synthesis method of D1 in Comparative Example 1, except that the dimethyl carbonate was replaced with diethyl carbonate, 46 g of an aqueous solution of an organic template D2 containing no alkyl substituents on the piperidinium ring carbon atom was obtained, which was calibrated with 0.1 mol / L hydrochloric acid solution to obtain a mass concentration of 27.2%, and the hydroxide content in the organic template was 2.4%.

[0056] Application Example 1: Preparation of SSZ-39 molecular sieve using the organic template agent piperidinium derivative P1 of Example 1

[0057] Aluminum source: Y molecular sieve, white to off-white in appearance, Si / Al2O3=5-20, Na2O content: <0.15%.

[0058] Silicon source: 30% silica sol.

[0059] Alkali source: sodium hydroxide or potassium hydroxide.

[0060] Template: the organic template piperidinium derivative P1 of Example 1.

[0061] Seed crystal: commercially available SSZ-39 molecular sieve was used.

[0062] First, 16g of Y molecular sieve (Si / Al2O3=5.5) was mixed with 150g of deionized water and stirred with a stirrer for 1h. Then, 45g of an aqueous solution of the organic template agent piperidinium derivative P1 of Example 1 (mass concentration of 26.2%), 14g of sodium hydroxide, 175g of a silicon source and 2g of seed crystals were added in sequence, the temperature was raised to 50°C, and stirred for 3h. The material was then poured into an autoclave, sealed and heated to 180°C, and hydrothermally reacted for 48h. The material was taken out, allowed to stand, filtered, and the filter cake was washed with deionized water until neutral. The material was dehydrated and dried, then placed in a muffle furnace, calcined at 300-400°C, and washed with water to obtain 52g (theoretical value: 70.5g) of a new SSZ-39 molecular sieve. The scanning electron microscope image of SSZ-39 molecular sieve is shown in FIG1 , the XRD spectrum of SSZ-39 molecular sieve is shown in FIG2 , and the X-ray fluorescence analysis result of SSZ-39 molecular sieve shows SAR=22.

[0063] Application Example 2: Preparation of SSZ-39 molecular sieve using the organic template agent piperidinium derivative P2 of Example 2

[0064] The preparation method refers to Application Example 1, except that the organic template agent piperidinium derivative P1 is replaced with an aqueous solution of the organic template agent piperidinium derivative P2 of Example 2, to obtain 53 g (theoretical value is 70.5 g) of the new SSZ-39 molecular sieve.

[0065] Application Example 3: Preparation of SSZ-39 molecular sieve using the organic template agent piperidinium derivative P3 of Example 3

[0066] The preparation method refers to Application Example 1, except that the organic template agent piperidinium derivative P1 is replaced with an aqueous solution of the organic template agent piperidinium derivative P3 of Example 3 to obtain 55 g (theoretical value is 70.5 g) of the new SSZ-39 molecular sieve.

[0067] Application Example 4: Preparation of SSZ-39 molecular sieve using the organic template agent piperidinium derivative P4 of Example 4

[0068] The preparation method refers to Application Example 1, except that the organic template agent piperidinium derivative P1 is replaced with an aqueous solution of the organic template agent piperidinium derivative P4 of Example 4, to obtain 57 g (theoretical value is 70.5 g) of the new SSZ-39 molecular sieve.

[0069] Comparative Application Example 1: Preparation of SSZ-39 molecular sieve using organic template D1 having no alkyl substituent on the piperidinium ring carbon atom of Comparative Example 1

[0070] The preparation method refers to Application Example 1, except that the organic template agent piperidinium derivative P1 is replaced by an aqueous solution of the organic template agent D1 in Comparative Example 1 which does not contain an alkyl substituent on the piperidinium ring carbon atom, to obtain 39 g (theoretical value is 70.5 g) of the new SSZ-39 molecular sieve.

[0071] Comparative Application Example 2: Preparation of SSZ-39 molecular sieve using organic template D2 having no alkyl substituent on the piperidinium ring carbon atom of Comparative Example 2

[0072] The preparation method refers to Application Example 1, except that the organic template agent piperidinium derivative P1 is replaced by an aqueous solution of an organic template agent D2 in Comparative Example 2 having no alkyl substituent on the piperidinium ring carbon atom, to obtain 41 g (theoretical value is 70.5 g) of a new SSZ-39 molecular sieve.

[0073] It can be seen from the above application examples 1-4 and comparative application examples 1-2 that the use of the organic template piperidinium derivative of the present invention to prepare SSZ-39 molecular sieve can significantly improve the yield of SSZ-39 molecular sieve, and the prepared SSZ-39 molecular sieve has high crystallinity, and also reduces the amount of organic template, reduces the production cost of the molecular sieve, and the preparation process is simple, with less pollution to the environment, which is conducive to the industrial production and application of molecular sieves.

[0074] Obviously, the above embodiments are merely examples for the purpose of illustrating the present invention and are not intended to limit the embodiments of the present invention. Those skilled in the art may make various modifications and variations to the present invention without departing from the spirit and scope of the present invention. Thus, to the extent such modifications and variations fall within the scope of the claims and their equivalents, the present invention is intended to encompass such modifications and variations.

Claims

1. An organic template piperidinium derivative for preparing a molecular sieve, characterized in that: The structure of the piperidinium derivative is shown in general formula I: Wherein, R1 and R2 are each independently selected from methyl, ethyl, propyl, butyl, pentyl, and hexyl; A1, A2, A3, A4, A5 are each independently selected from hydrogen, methyl, ethyl, propyl, butyl, pentyl, hexyl, methoxy, ethoxy, propoxy, butoxy, pentyloxy, hexyl, wherein at least one of A1, A2, A3, A4, A5 is selected from methyl, ethyl, propyl, butyl, pentyl, hexyl, and at least one is selected from methoxy, ethoxy, propoxy, butoxy, pentyloxy, hexyl.

2. The organic template piperidinium derivative of general formula (I) according to claim 1, characterized in that: In the general formula I, R1 and R2 are each independently selected from methyl, ethyl, and propyl; A1, A2, A3, A4, and A5 are each independently selected from hydrogen, methyl, ethyl, propyl, methoxy, ethoxy, and propoxy, wherein at least one of A1, A2, A3, A4, and A5 is selected from methyl, ethyl, and propyl, and at least one is selected from methoxy, ethoxy, and propoxy.

3. The organic template piperidinium derivative of general formula (I) according to claim 1, characterized in that: The piperidinium derivative is any one of the following compounds:

4. Use of the piperidinium derivative of general formula I as claimed in any one of claims 1 to 3 as an organic template in the preparation of molecular sieves, characterized in that: The molecular sieve is SSZ-39 molecular sieve.

5. A method for preparing SSZ-39 molecular sieve, characterized in that: The method uses the piperidinium derivative represented by the general formula I described in any one of claims 1 to 3 as an organic template agent.

6. An SSZ-39 molecular sieve prepared by the preparation method according to claim 5.

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