Method for preparing SSZ-39 molecular sieve with pan-silica-alumina ratio

Abstract

The invention provides a method for preparing an SSZ-39 molecular sieve with a general silica-alumina ratio, and relates to the technical field of molecular sieves. The preparation method comprises the following steps: mixing a template agent, water, an alkali source, a seed crystal and a silicon source to obtain gel; the alkali source is alkali metal hydroxide, and the seed crystal is a small-hole SAPO molecular sieve; carrying out hydrothermal crystallization on the gel to obtain a crystallized product; and calcining the crystallized product to obtain the SSZ-39 molecular sieve. The SSZ-39 with a series of silica-alumina ratios is synthesized by an aluminum-source-free seed crystal method for the first time, alkali metal cations in an alkali source play a structure guiding role, the amount of a template agent is reduced by regulating and controlling the amount of the alkali metal cations, and the yield of the molecular sieve can be remarkably improved by adopting specific seed crystals. According to the preparation method provided by the invention, the mold-to-silicon ratio is only 0.02, the highest yield can reach 34%, and the preparation cost can be controlled at a very low level.

Description

Technical Field

[0001] The invention relates to the technical field of molecular sieves, and in particular to a method for preparing a pan-silicon-aluminum ratio SSZ-39 molecular sieve. Background Art

[0002] As a new generation of small-pore catalyst, SSZ-39 molecular sieve has excellent performance in reactions such as denitrification and methanol to olefins, so its commercial potential is very high.

[0003] However, there are three problems in the synthesis of traditional SSZ-39 molecular sieves: (1) the high dosage of expensive templates; (2) the use of commercial molecular sieves as aluminum sources; and (3) low yields. These three problems have led to high synthesis costs for SSZ-39 molecular sieves, making them difficult to industrialize and commercialize. The lowest template dosage in the relevant technology is 0.1 in terms of template-to-silicon ratio (i.e., the molar ratio of template to silicon), and the average yield is 20%. Summary of the invention

[0004] In view of this, the purpose of the present invention is to provide a method for preparing a pan-silicon-aluminum ratio SSZ-39 molecular sieve. The present invention uses an aluminum-free seed crystal method to synthesize a series of SSZ-39 molecular sieves with a silicon-aluminum ratio, with a model silicon ratio of only 0.02, a maximum yield of 34%, and a significant reduction in preparation cost.

[0005] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0006] The present invention provides a method for preparing a pan-silicon-aluminum ratio SSZ-39 molecular sieve, comprising the following steps:

[0007] The template, water, alkali source, seed crystal and silicon source are mixed to obtain a gel; the alkali source is an alkali metal hydroxide, and the seed crystal is a small-pore SAPO molecular sieve; the composition of the gel satisfies the molar ratio of SiO2: template: alkali metal hydroxide: Al2O3: H2O = 1: 0.02: 0.58: 0.002-0.012: 7.5, wherein the molar amount of SiO2 is obtained by converting the silicon element in the silicon source to SiO2, and the molar amount of Al2O3 is obtained by converting the aluminum element in the seed crystal to Al2O3;

[0008] performing hydrothermal crystallization on the gel to obtain a crystallized product;

[0009] The crystallized product is calcined to obtain SSZ-39 molecular sieve.

[0010] Preferably, the template is 1,1,3,5-tetramethylpiperidinium hydroxide.

[0011] Preferably, the alkali source is sodium hydroxide and / or potassium hydroxide.

[0012] Preferably, the silicon source is one or more of silica gel, silica sol and white carbon black.

[0013] Preferably, the small pore SAPO molecular sieve is one or more of AEI SAPO molecular sieve, CHA SAPO molecular sieve, LEV SAPO molecular sieve, RHO SAPO molecular sieve, ERI SAPO molecular sieve and KFI SAPO molecular sieve.

[0014] Preferably, the hydrothermal crystallization temperature is 130-160° C., and the time is 1-5 days.

[0015] Preferably, after the hydrothermal crystallization, the method further comprises sequentially performing solid-liquid separation and drying on the obtained crystallization reaction liquid to obtain the crystallized product.

[0016] Preferably, the calcination temperature is 550-750° C. and the calcination time is 4-10 hours.

[0017] Preferably, the silicon to aluminum molar ratio of the SSZ-39 molecular sieve is 7-19.

[0018] Preferably, after the calcination, the process further comprises subjecting the calcined molecular sieve to ammonium ion exchange and re-calcination in sequence to obtain a hydrogen-type SSZ-39 molecular sieve.

[0019] The invention provides a method for preparing a pan-silicon-aluminum ratio SSZ-39 molecular sieve, comprising the following steps: mixing a template, water, an alkali source, a seed crystal and a silicon source to obtain a gel; the alkali source is an alkali metal hydroxide, and the seed crystal is a small-pore SAPO molecular sieve; the composition of the gel satisfies a molar ratio of SiO2: template: alkali metal hydroxide: Al2O3: H2O=1: 0.02: 0.58: 0.002-0.012: 7.5, wherein the molar amount of SiO2 is obtained by converting the silicon element in the silicon source into SiO2, and the molar amount of Al2O3 is obtained by converting the aluminum element in the seed crystal into Al2O3; hydrothermally crystallizing the gel to obtain a crystallized product; and calcining the crystallized product to obtain the SSZ-39 molecular sieve. The present invention synthesizes a series of SSZ-39 molecular sieves with different silicon-aluminum ratios for the first time by using a non-aluminum source seed method. In the present invention, the alkali metal cations in the alkali source play a structural guiding role. The present invention reduces the amount of the template by regulating the amount of the alkali metal cations. The present invention uses specific seeds, which can significantly improve the yield of the molecular sieve; and the silicon-aluminum ratio of the SSZ-39 molecular sieve can be easily and conveniently regulated by regulating the amount of the seeds. The preparation method provided by the present invention has a template-silicon ratio of only 0.02, and the highest yield can reach 34%, which can control the preparation cost at a very low level. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1XRD patterns of the SSZ-39 molecular sieves (S1-S6) prepared in Examples 1-6;

[0021] Figure 2 XRD patterns of SSZ-39 molecular sieves (S3, S7-S11) prepared in Example 3 and Examples 7-11;

[0022] Figure 3 XRD patterns of SSZ-39 molecular sieves (S3, S12-S15) prepared in Example 3 and Examples 12-15;

[0023] Figure 4 XRD patterns of SSZ-39 molecular sieves (S3, S16-S19) prepared in Example 3 and Examples 16-19;

[0024] Figure 5 XRD patterns of SSZ-39 molecular sieves (S3, S20-S24) prepared in Example 3 and Examples 20-24;

[0025] Figure 6 This is the XRD diagram of the molecular sieve (S25-S30) prepared in Comparative Example 1. DETAILED DESCRIPTION

[0026] The present invention provides a method for preparing a pan-silicon-aluminum ratio SSZ-39 molecular sieve, comprising the following steps:

[0027] The template, water, alkali source, seed crystal and silicon source are mixed to obtain a gel; the alkali source is an alkali metal hydroxide, and the seed crystal is a small-pore SAPO molecular sieve; the composition of the gel satisfies the molar ratio of SiO2: template: alkali metal hydroxide: Al2O3: H2O = 1: 0.02: 0.58: 0.002-0.012: 7.5, wherein the molar amount of SiO2 is obtained by converting the silicon element in the silicon source to SiO2, and the molar amount of Al2O3 is obtained by converting the aluminum element in the seed crystal to Al2O3;

[0028] performing hydrothermal crystallization on the gel to obtain a crystallized product;

[0029] The crystallized product is calcined to obtain SSZ-39 molecular sieve.

[0030] In the present invention, unless otherwise specified, the raw materials involved are commercially available products well known in the art.

[0031] The invention mixes template, water, alkali source, crystal seed and silicon source to obtain gel.

[0032] In the present invention, the alkali source is an alkali metal hydroxide, preferably sodium hydroxide and / or potassium hydroxide; when the alkali source is sodium hydroxide and potassium hydroxide, the present invention has no special requirements for the ratio of the sodium hydroxide and potassium hydroxide, as long as the molar ratio of the alkali metal hydroxide in the subsequent gel is satisfied. In the present invention, the alkali metal hydroxide acts as an alkali source, and the alkali metal cation therein plays a structural guiding role.

[0033] In the present invention, the silicon source is preferably one or more of silica gel, silica sol and white carbon black. The silica gel is such as column chromatography silica gel or silica gel powder. The silica sol is such as 30wt% silica sol or HS-40.

[0034] In the present invention, the template is preferably 1,1,3,5-tetramethylpiperidinium hydroxide (DMDMPOH for short). In an embodiment of the present invention, the 1,1,3,5-tetramethylpiperidinium hydroxide is added in the form of a 1,1,3,5-tetramethylpiperidinium hydroxide aqueous solution, and the mass fraction of the 1,1,3,5-tetramethylpiperidinium hydroxide aqueous solution is 25%.

[0035] In the present invention, the water is preferably distilled water.

[0036] In the present invention, the seed is a small-pore SAPO molecular sieve, and the small-pore SAPO molecular sieve is preferably one or more of AEI type SAPO molecular sieve, CHA type SAPO molecular sieve, LEV type SAPO molecular sieve, RHO type SAPO molecular sieve, ERI type SAPO molecular sieve and KFI type SAPO molecular sieve. In an embodiment of the present invention, the AEI type SAPO molecular sieve, CHA type SAPO molecular sieve, LEV type SAPO molecular sieve, RHO type SAPO molecular sieve, ERI type SAPO molecular sieve and KFI type SAPO molecular sieve are respectively recorded as SAPO-AEI seed, SAPO-CHA seed, SAPO-LEV seed, SAPO-RHO seed, SAPO-ERI seed and SAPO-KFI seed. The present invention has no special requirements for the source of the small-pore SAPO molecular sieve, and is prepared using commercially available goods or a preparation method well known to those skilled in the art. In the embodiment of the present invention, the AEI type SAPO molecular sieve is SAPO-18 molecular sieve; the CHA type SAPO molecular sieve is SAPO-34 molecular sieve; the LEV type SAPO molecular sieve is SAPO-35 molecular sieve; the ERI type SAPO molecular sieve is SAPO-17 molecular sieve; the RHO type SAPO molecular sieve and the KFI type SAPO molecular sieve are prepared by the following methods respectively:

[0037] Preparation of RHO-type SAPO molecular sieve: orthophosphoric acid (85wt%), tetraethyl orthosilicate, aluminum isopropoxide solution and deionized water are mixed, and after the synthetic solution is stirred for 2h, a template agent N,N′-dimethylethylenediamine is added to make the gel ratio of tetraethyl orthosilicate: Al2O3: P2O5: N,N′-dimethylethylenediamine: water = 1.3:1.3:1:5:167, and stirring is continued for 4 hours; the mixture is loaded into a kettle, and crystallized at 200°C for 12h, the solid product is filtered and recovered, washed three times with deionized water, and dried at 110°C overnight; finally, calcined at 550°C for 4 hours to remove organic matter to obtain a RHO-type SAPO molecular sieve;

[0038] Preparation of KFI type SAPO molecular sieve: orthophosphoric acid (85wt%), dipropylamine and deionized water are mixed, and the synthetic solution is stirred for 2h, and then tetraethyl orthosilicate and aluminum isopropoxide are added, and stirred for 12h, and hexadecyltrimethylammonium bromide is added, and stirred for 12h, so that the gel ratio is tetraethyl orthosilicate: Al2O3: P2O5: dipropylamine: CTAB: water = 0.3:1:1:2:0.15:50; the mixture is loaded into an autoclave, and crystallized at 200°C for 24h, and the solid product is recovered by filtration, washed three times with deionized water, and dried at 110°C overnight; finally, calcined at 550°C for 4h to remove organic matter to obtain KFI type SAPO molecular sieve.

[0039] In the present invention, the seed crystal also serves as an aluminum source. The present invention uses the above-mentioned specific seed crystals to improve the yield of SSZ-39 molecular sieve. In the present invention, the mass of the seed crystal is preferably 1-6% of the mass of the silicon source, which can be 1%, 2%, 3%, 4%, 5% or 6%, and the mass of the silicon source is calculated as SiO2.

[0040] In the present invention, the method of mixing the template, water, alkali source, seed crystal and silicon source is preferably: adding the template, water, alkali source and seed crystal into a reaction container, stirring evenly under closed and room temperature conditions; then adding the silicon source thereto, stirring sufficiently to form a uniform gel. The present invention adopts the mixing method to first form an aluminum-rich gel, and then add the silicon source to form small particles of a silicon core structure coated with aluminum gel, which is conducive to the formation of crystals.

[0041] In the present invention, the composition of the gel satisfies the molar ratio of SiO2: template: alkali metal hydroxide: Al2O3: H2O = 1: 0.02: 0.58: 0.002 ~ 0.012: 7.5, which can be 1: 0.02: 0.58: 0.002: 7.5, 1: 0.02: 0.58: 0.004: 7.5, 1: 0.02: 0.58: 0.006: 7.5, 1: 0.02: 0.58: 0.008: 7.5, 1: 0.02: 0.58: 0.010: 7.5 or 1: 0.02: 0.58: 0.012: 7.5, wherein the molar amount of SiO2 is obtained by converting the silicon element in the silicon source into SiO2, and the molar amount of Al2O3 is obtained by converting the aluminum element in the seed crystal into Al2O3. In the present invention, the alkali metal cations in the alkali metal hydroxide play a structural guiding role, overlapping with the template agent, so the amount of template agent can be reduced by regulating the amount of alkali metal cations in the system, and the SSZ-39 molecule can be prepared using a trace amount of template agent. The template-silicon ratio in the present invention is only 0.02. In addition, the present invention can simply and conveniently achieve the regulation of the silicon-aluminum ratio of the SSZ-39 molecular sieve by regulating the amount of seed crystals added. Specifically, the larger the amount of seed crystals added, the lower the silicon-aluminum ratio of the product; the smaller the amount of seed crystals added, the higher the silicon-aluminum ratio of the product; the present invention regulates the silicon-aluminum ratio range of SSZ-39 in a simple way.

[0042] After obtaining the gel, the present invention performs hydrothermal crystallization on the gel to obtain a crystallized product.

[0043] In the present invention, the hydrothermal crystallization temperature is preferably 130-160° C., and may be 130, 140, 150 or 160° C., and the time is preferably 1-5 days, and may be 1 day, 2 days, 3 days, 4 days or 5 days.

[0044] After the hydrothermal crystallization, the present invention preferably performs solid-liquid separation and drying on the obtained crystallization reaction liquid in sequence to obtain the crystallized product. The present invention has no particular requirements on the solid-liquid separation method, and a solid-liquid separation method well known to those skilled in the art, such as centrifugation, can be used. In the present invention, the drying temperature is preferably 90°C.

[0045] After obtaining the crystallized product, the present invention calcines the crystallized product to obtain SSZ-39 molecular sieve. In the present invention, the calcination temperature is preferably 550-750°C, and can be 550, 600, 650, 700 or 750°C, and the time is preferably 4-10h, and can be 4, 5, 6, 7, 8, 9 or 10h, and the template in the molecular sieve is removed by the calcination.

[0046] After the calcination, the present invention can also sequentially perform ammonium ion exchange and re-calcination on the calcined molecular sieve to obtain a hydrogen-type SSZ-39 molecular sieve (H-SSZ-39). The present invention preferably places the calcined molecular sieve in an ammonium chloride solution under water bath conditions to perform the ammonium ion exchange; the concentration of the ammonium chloride solution is preferably 1 mol / L, the temperature of the ammonium ion exchange is preferably 80°C, and the time is preferably 2h. After the ammonium ion exchange is completed, the obtained reaction liquid is preferably separated into a solid and liquid state (such as suction filtration), and the obtained solid is dried and then calcined again; the drying temperature is preferably 90°C, the re-calcination temperature is preferably 500°C, and the time is preferably 4h.

[0047] In the present invention, the silicon-aluminum molar ratio (Si / Al) of the SSZ-39 molecular sieve is 7 to 19, and the SSZ-39 molecular sieve has an AEI topological structure.

[0048] The present invention provides a method for preparing SSZ-39 molecular sieve with a silicon-aluminum atomic ratio in the range of 7 to 19 by using only a trace amount of template agent, the template-silicon ratio is only 0.02, the maximum yield can reach 34%, and the preparation cost is controlled at a very low level.

[0049] In order to further illustrate the present invention, the method for preparing the pan-silicon-aluminum ratio SSZ-39 molecular sieve provided by the present invention is described in detail below in conjunction with examples, but they should not be understood as limiting the scope of protection of the present invention.

[0050] In various embodiments:

[0051] The template agent is 1,1,3,5-tetramethylpiperidinium hydroxide aqueous solution (25wt%);

[0052] SAPO-AEI seed crystals are: SAPO-18 molecular sieve seed crystals;

[0053] SAPO-CHA seed crystals are: SAPO-34 molecular sieve seed crystals;

[0054] SAPO-LEV seeds are: SAPO-35 molecular sieve seeds;

[0055] SAPO-ERI seeds are: SAPO-17 molecular sieve seeds;

[0056] The preparation method of SAPO-RHO seed crystal is as follows:

[0057] Orthophosphoric acid (85wt%), tetraethyl orthosilicate, aluminum isopropoxide solution and deionized water are mixed, and after the synthetic solution is stirred for 2h, the template N,N′-dimethylethylenediamine is added to make the gel ratio of tetraethyl orthosilicate:Al2O3:P2O5:N,N′-dimethylethylenediamine:water=1.3:1.3:1:5:167, and the stirring is continued for 4h; the mixture is loaded into a kettle and crystallized at 200°C for 12h, the solid product is recovered by filtration, washed three times with deionized water, and dried at 110°C overnight; finally, it is calcined at 550°C for 4h to remove organic matter.

[0058] The preparation method of SAPO-KFI seed crystal is as follows:

[0059] Orthophosphoric acid (85 wt%), dipropylamine and deionized water were mixed, and the synthetic solution was stirred for 2 h, and then tetraethyl orthosilicate and aluminum isopropoxide were added, and the mixture was stirred for 12 h. Hexadecyltrimethylammonium bromide was added and the mixture was stirred for 12 h, so that the gel ratio was tetraethyl orthosilicate: Al2O3: P2O5: dipropylamine: CTAB: water = 0.3:1:1:2:0.15:50; the mixture was loaded into a kettle and crystallized at 200°C for 24 h, the solid product was recovered by filtration, washed three times with deionized water, and dried at 110°C overnight; finally, the mixture was calcined at 550°C for 4 h to remove organic matter.

[0060] Example 1

[0061] Add the template, distilled water, sodium hydroxide and SAPO-AEI seed crystals into a reaction container, stir evenly under closed and room temperature conditions, then add the layer column chromatography silica gel and stir, and stir thoroughly until a uniform gel is formed; wherein the molar ratio of the active ingredients SiO2, template, NaOH, Al2O3 and H2O in the gel is 1:0.02:0.58:0.002:7.5, and the mass of the seed crystal is 1% of the mass of SiO2;

[0062] The gel was placed in an oven at 150° C. for crystallization for 5 days. The obtained product was centrifuged, dried at 90° C., and then calcined at 600° C. for 5 h to obtain SSZ-39 molecular sieve (denoted as S1).

[0063] The prepared SSZ-39 molecular sieve was placed in a 1 mol / L aqueous solution of ammonium chloride, water bathed at 80°C for 2 h, filtered, dried at 90°C, and then calcined at 500°C for 4 h to obtain H-SSZ-39 molecular sieve.

[0064] Example 2

[0065] Add the template, distilled water, sodium hydroxide and SAPO-AEI seed crystals into a reaction container, stir evenly under closed and room temperature conditions, then add column chromatography silica gel and stir, and stir thoroughly until a uniform gel is formed; wherein the molar ratio of the active ingredients SiO2, template, NaOH, Al2O3 and H2O in the gel is 1:0.02:0.58:0.004:7.5, and the mass of the seed crystal is 2% of the mass of SiO2;

[0066] The gel was placed in an oven at 150°C for crystallization for 5 days. The obtained product was centrifuged, dried at 90°C, and then calcined at 600°C for 5 hours to obtain SSZ-39 molecular sieve (denoted as S2).

[0067] Example 3

[0068] Add the template, distilled water, sodium hydroxide and SAPO-AEI seed crystals into a reaction container, stir evenly under closed and room temperature conditions, then add column chromatography silica gel and stir, and stir thoroughly until a uniform gel is formed; wherein the molar ratio of the active ingredients SiO2, template, NaOH, Al2O3 and H2O in the gel is 1:0.02:0.58:0.006:7.5, and the mass of the seed crystal is 3% of the mass of SiO2;

[0069] The gel was placed in an oven at 150°C for crystallization for 5 days, the obtained product was centrifuged, dried at 90°C, and then calcined at 600°C for 5 hours to obtain SSZ-39 molecular sieve (denoted as S3).

[0070] Example 4

[0071] Add the template, distilled water, sodium hydroxide and SAPO-AEI seed crystals into a reaction container, stir evenly under closed and room temperature conditions, then add column chromatography silica gel and stir, and stir thoroughly until a uniform gel is formed; wherein the molar ratio of the active ingredients SiO2, template, NaOH, Al2O3 and H2O in the gel is 1:0.02:0.58:0.008:7.5, and the mass of the seed crystal is 4% of the mass of SiO2;

[0072] The gel was placed in an oven at 150°C for crystallization for 5 days, the obtained product was centrifuged, dried at 90°C, and then calcined at 600°C for 5 hours to obtain SSZ-39 molecular sieve (denoted as S4).

[0073] Example 5

[0074] Add the template, distilled water, sodium hydroxide and SAPO-AEI seed crystals into a reaction container, stir evenly under closed and room temperature conditions, then add column chromatography silica gel and stir, and stir thoroughly until a uniform gel is formed; wherein the molar ratio of the active ingredients SiO2, template, NaOH, Al2O3, and H2O in the gel is 1:0.02:0.58:0.010:7.5, and the mass of the seed crystal is 5% of the mass of SiO2;

[0075] The gel was placed in an oven at 150°C for crystallization for 5 days, the obtained product was centrifuged, dried at 90°C, and then calcined at 600°C for 5 hours to obtain SSZ-39 molecular sieve (denoted as S5).

[0076] Example 6

[0077] Add the template, distilled water, sodium hydroxide and SAPO-AEI seed crystals into a reaction container, stir evenly under closed and room temperature conditions, then add column chromatography silica gel and stir, and stir thoroughly until a uniform gel is formed; wherein the molar ratio of the active ingredients SiO2, template, NaOH, Al2O3 and H2O in the gel is 1:0.02:0.58:0.012:7.5, and the mass of the seed crystal is 6% of the mass of SiO2;

[0078] The gel was placed in an oven at 150°C for crystallization for 5 days. The obtained product was centrifuged, dried at 90°C, and then calcined at 600°C for 5 hours to obtain SSZ-39 molecular sieve (denoted as S6).

[0079] Figure 1 XRD patterns of the SSZ-39 molecular sieves (S1-S6) prepared in Examples 1-6.

[0080] The silicon-to-aluminum ratio and yield of the SSZ-39 molecular sieve products prepared in Examples 1 to 6 are listed in Table 1, wherein the silicon-to-aluminum ratio of the products is obtained by inductively coupled plasma emission spectroscopy (ICP) testing, and the yield is calculated as follows: mass of the product / (mass of SiO2 in the raw material + mass of Al2O3 in the raw material). The testing and calculation methods of other examples are the same.

[0081] Table 1 Silicon-aluminum ratio and yield of SSZ-39 molecular sieve products prepared in Examples 1 to 6

[0082]

[0083] It can be seen from Table 1 that with the increase of seed crystal dosage, the silicon-aluminum ratio of the product decreases and the yield increases, until a small amount of miscellaneous items (MFI, less than 5%) begin to appear after 6%. In Table 1, the SSZ-39 molecular sieve product S6 only increases the amount of seed crystals in the synthesis, but the amount of hydroxide is not increased, resulting in insufficient basicity of the system, thus forming an AEI+MFI structure.

[0084] Example 7

[0085] Add the template, distilled water, sodium hydroxide, potassium hydroxide and SAPO-AEI seed crystals into a reaction container, stir evenly under closed and room temperature conditions, then add column chromatography silica gel and stir, and stir thoroughly until a uniform gel is formed; wherein the molar ratio of the active ingredients SiO2, template, NaOH, KOH, Al2O3 and H2O in the gel is 1:0.02:0.464:0.116:0.006:7.5, and the mass of the seed crystal is 3% of the mass of SiO2;

[0086] The gel was placed in an oven at 150°C for crystallization for 5 days, the obtained product was centrifuged, dried at 90°C, and then calcined at 600°C for 5 hours to obtain SSZ-39 molecular sieve (denoted as S7).

[0087] Example 8

[0088] Add the template, distilled water, sodium hydroxide, potassium hydroxide and SAPO-AEI seed crystals into the reaction vessel, stir evenly under closed and room temperature conditions, then add column chromatography silica gel and stir until a uniform gel is formed. The molar ratio of the active ingredients SiO2, template, NaOH, KOH, Al2O3 and H2O in the gel is 1:0.02:0.348:0.232:0.006:7.5, and the mass of the seed crystal is 3% of the mass of SiO2;

[0089] The gel was placed in an oven at 150°C for crystallization for 5 days. The obtained product was centrifuged, dried at 90°C, and then calcined at 600°C for 5 hours to obtain SSZ-39 molecular sieve (denoted as S8).

[0090] Example 9

[0091] Add the template, distilled water, sodium hydroxide, potassium hydroxide and SAPO-AEI seed crystals into a reaction container, stir evenly under closed and room temperature conditions, then add column chromatography silica gel and stir, and stir thoroughly until a uniform gel is formed; wherein the molar ratio of the active ingredients SiO2, template, NaOH, KOH, Al2O3 and H2O in the gel is 1:0.02:0.232:0.348:0.006:7.5, and the mass of the seed crystal is 3% of the mass of SiO2;

[0092] The gel was placed in an oven at 150°C for crystallization for 5 days, the obtained product was centrifuged, dried at 90°C, and then calcined at 600°C for 5 hours to obtain SSZ-39 molecular sieve (denoted as S9).

[0093] Example 10

[0094] Add the template, distilled water, sodium hydroxide, potassium hydroxide and SAPO-AEI seed crystals into a reaction container, stir evenly under closed and room temperature conditions, then add column chromatography silica gel and stir, and stir thoroughly until a uniform gel is formed; wherein the molar ratio of the active ingredients SiO2, template, NaOH, KOH, Al2O3 and H2O in the gel is 1:0.02:0.116:0.464:0.006:7.5, and the mass of the seed crystal is 3% of the mass of SiO2;

[0095] The gel was placed in an oven at 150°C for crystallization for 5 days, the obtained product was centrifuged, dried at 90°C, and then calcined at 600°C for 5 hours to obtain SSZ-39 molecular sieve (denoted as S10).

[0096] Embodiment 11

[0097] Add the template, distilled water, sodium hydroxide, potassium hydroxide and SAPO-AEI seed crystals into a reaction container, stir evenly under closed and room temperature conditions, then add column chromatography silica gel and stir, and stir thoroughly until a uniform gel is formed; wherein the molar ratio of the active ingredients SiO2, template, NaOH, KOH, Al2O3 and H2O in the gel is 1:0.02:0:0.58:0.006:7.5, and the mass of the seed crystal is 3% of the mass of SiO2;

[0098] The gel was placed in an oven at 150° C. for crystallization for 5 days. The obtained product was centrifuged, dried at 90° C., and then calcined at 600° C. for 5 h to obtain SSZ-39 molecular sieve (denoted as S11).

[0099] Figure 2 XRD diagrams of the SSZ-39 molecular sieves (S3, S7-S11) prepared in Example 3 and Examples 7-11.

[0100] The silicon-to-aluminum ratio and yield of the SSZ-39 molecular sieve products in Example 3 and Examples 7 to 11 are listed in Table 2.

[0101] Table 2 Silicon-aluminum ratio and yield of SSZ-39 molecular sieve products in Example 3 and Examples 7 to 11

[0102]

[0103] It can be seen from Table 2 that with the increase of the proportion of KOH in the metal hydroxide, the silicon-aluminum ratio of the product gradually decreases, and the yield remains almost unchanged.

[0104] Example 12

[0105] Add the template, distilled water, sodium hydroxide and SAPO-AEI seed crystals into a reaction container, stir evenly under closed and room temperature conditions, then add column chromatography silica gel and stir, and stir thoroughly until a uniform gel is formed; wherein the molar ratio of the active ingredients SiO2, template, NaOH, Al2O3 and H2O in the gel is 1:0.02:0.58:0.006:7.5, and the mass of the seed crystal is 3% of the mass of SiO2;

[0106] The gel was placed in an oven at 150°C for crystallization for 1 day. The obtained product was centrifuged, dried at 90°C, and then calcined at 600°C for 5h to obtain SSZ-39 molecular sieve (denoted as S12).

[0107] Embodiment 13

[0108] Add the template, distilled water, sodium hydroxide and SAPO-AEI seed crystals into the reaction vessel, stir evenly under closed and room temperature conditions, then add column chromatography silica gel and stir until a uniform gel is formed. The molar ratio of the active ingredients SiO2, template, NaOH, Al2O3 and H2O in the gel is 1:0.02:0.58:0.006:7.5, and the mass of the seed crystal is 3% of the mass of SiO2;

[0109] The gel was placed in an oven at 150°C for crystallization for 2 days, the obtained product was centrifuged, dried at 90°C, and then calcined at 600°C for 5h to obtain SSZ-39 molecular sieve (denoted as S13).

[0110] Embodiment 14

[0111] Add the template, distilled water, sodium hydroxide and SAPO-AEI seed crystals into the reaction vessel, stir evenly under closed and room temperature conditions, then add column chromatography silica gel and stir until a uniform gel is formed. The molar ratio of the active ingredients SiO2, template, NaOH, Al2O3 and H2O in the gel is 1:0.02:0.58:0.006:7.5, and the mass of the seed crystal is 3% of the mass of SiO2;

[0112] The gel was placed in an oven at 150°C for crystallization for 3 days, the obtained product was centrifuged, dried at 90°C, and then calcined at 600°C for 5h to obtain SSZ-39 molecular sieve (denoted as S14).

[0113] Embodiment 15

[0114] Add the template, distilled water, sodium hydroxide and SAPO-AEI seed crystals into the reaction vessel, stir evenly under closed and room temperature conditions, then add column chromatography silica gel and stir until a uniform gel is formed. The molar ratio of the active ingredients SiO2, template, NaOH, Al2O3 and H2O in the gel is 1:0.02:0.58:0.006:7.5, and the mass of the seed crystal is 3% of the mass of SiO2;

[0115] The gel was placed in an oven at 150°C for crystallization for 4 days. The obtained product was centrifuged, dried at 90°C, and then calcined at 600°C for 5 hours to obtain SSZ-39 molecular sieve (denoted as S15).

[0116] Figure 3 XRD diagrams of the SSZ-39 molecular sieves (S3, S12-S15) prepared in Example 3 and Examples 12-15.

[0117] The silicon-to-aluminum ratio and yield of the SSZ-39 molecular sieve products prepared in Example 3 and Examples 12 to 15 are listed in Table 3.

[0118] Table 3 Silicon-aluminum ratio and yield of SSZ-39 molecular sieve products prepared in Example 3 and Examples 12 to 15

[0119]

[0120] It can be seen from Table 3 that as the crystallization time increases, the yield increases, but there is little improvement from the fourth day to the fifth day, indicating that the yield has reached a critical point.

[0121] Example 16

[0122] Add the template, distilled water, sodium hydroxide and SAPO-AEI seed crystals into a reaction container, stir evenly under closed and room temperature conditions, then add 30wt% silica sol and stir until a uniform gel is formed; wherein the molar ratio of the active ingredients SiO2, template, NaOH, Al2O3 and H2O in the gel is 1:0.02:0.58:0.006:7.5, and the mass of the seed crystal is 3% of the mass of SiO2;

[0123] The gel was placed in an oven at 150°C for crystallization for 5 days, the obtained product was centrifuged, dried at 90°C, and then calcined at 600°C for 5 hours to obtain SSZ-39 molecular sieve (denoted as S16).

[0124] Embodiment 17

[0125] Add the template, distilled water, sodium hydroxide and SAPO-AEI seed crystals into a reaction container, stir evenly under closed and room temperature conditions, then add white carbon black and stir, and stir thoroughly until a uniform gel is obtained; wherein the molar ratio of the active ingredients SiO2, template, NaOH, Al2O3 and H2O in the gel is 1:0.02:0.58:0.006:7.5, and the mass of the seed crystal is 3% of the mass of SiO2;

[0126] The gel was placed in an oven at 150°C for crystallization for 5 days, the obtained product was centrifuged, dried at 90°C, and then calcined at 600°C for 5 hours to obtain SSZ-39 molecular sieve (denoted as S17).

[0127] Embodiment 18

[0128] Add the template, distilled water, sodium hydroxide and SAPO-AEI seed crystals into a reaction container, stir evenly under closed and room temperature conditions, then add 90wt% silica gel powder and stir, and stir thoroughly until a uniform gel is obtained; wherein the molar ratio of the active ingredients SiO2, template, NaOH, Al2O3 and H2O in the gel is 1:0.02:0.58:0.006:7.5, and the mass of the seed crystal is 3% of the mass of SiO2;

[0129] The gel was placed in an oven at 150°C for crystallization for 5 days. The obtained product was centrifuged, dried at 90°C, and then calcined at 600°C for 5 hours to obtain SSZ-39 molecular sieve (denoted as S18).

[0130] Embodiment 19

[0131] Add the template, distilled water, sodium hydroxide and SAPO-AEI seed crystals into a reaction container, stir evenly under closed and room temperature conditions, then add HS-40 and stir until a uniform gel is obtained; the molar ratio of the active ingredients SiO2, template, NaOH, Al2O3 and H2O in the gel is 1:0.02:0.58:0.006:7.5, and the mass of the seed crystal is 3% of the mass of SiO2;

[0132] The gel was placed in an oven at 150°C for crystallization for 5 days. The obtained product was centrifuged, dried at 90°C, and then calcined at 600°C for 5 hours to obtain SSZ-39 molecular sieve (denoted as S19).

[0133] Figure 4 XRD diagrams of the SSZ-39 molecular sieves (S3, S16-S19) prepared in Example 3 and Examples 16-19.

[0134] The silicon-to-aluminum ratio and yield of the SSZ-39 molecular sieve products prepared in Example 3 and Examples 16 to 19 are listed in Table 4.

[0135] Table 4 Silicon-aluminum ratio and yield of SSZ-39 molecular sieve products prepared in Example 3 and Examples 16 to 19

[0136]

[0137] It can be seen from Table 4 that the type of silicon source has little effect on the product.

[0138] Embodiment 20

[0139] Add the template, distilled water, sodium hydroxide and SAPO-CHA seed crystals into a reaction container, stir evenly under closed and room temperature conditions, then add column chromatography silica gel and stir, and stir thoroughly until a uniform gel is formed; wherein the molar ratio of the active ingredients SiO2, template, NaOH, Al2O3 and H2O in the gel is 1:0.02:0.58:0.006:7.5, and the mass of the seed crystal is 3% of the mass of SiO2;

[0140] The gel was placed in an oven at 150°C for crystallization for 5 days, the obtained product was centrifuged, dried at 90°C, and then calcined at 600°C for 5 hours to obtain SSZ-39 molecular sieve (denoted as S20).

[0141] Embodiment 21

[0142] Add the template, distilled water, sodium hydroxide and SAPO-LEV seed crystals into a reaction container, stir evenly under closed and room temperature conditions, then add chromatography silica gel and stir until a uniform gel is formed; wherein the molar ratio of the active ingredients SiO2, template, NaOH, Al2O3 and H2O in the gel is 1:0.02:0.58:0.006:7.5, and the mass of the seed crystal is 3% of the mass of SiO2;

[0143] The gel was placed in an oven at 150°C for crystallization for 5 days. The obtained product was centrifuged, dried at 90°C, and then calcined at 600°C for 5 hours to obtain SSZ-39 molecular sieve (denoted as S21).

[0144] Embodiment 22

[0145] Add the template, distilled water, sodium hydroxide and SAPO-ERI seed crystals into a reaction container, stir evenly under closed and room temperature conditions, then add chromatography silica gel and stir until a uniform gel is formed; wherein the molar ratio of the active ingredients SiO2, template, NaOH, Al2O3 and H2O in the gel is 1:0.02:0.58:0.006:7.5, and the mass of the seed crystal is 3% of the mass of SiO2;

[0146] The gel was placed in an oven at 150°C for crystallization for 5 days. The obtained product was centrifuged, dried at 90°C, and then calcined at 600°C for 5 hours to obtain SSZ-39 molecular sieve (denoted as S22).

[0147] Embodiment 23

[0148] Add the template, distilled water, sodium hydroxide and SAPO-RHO seed crystals into a reaction container, stir evenly under closed and room temperature conditions, then add column chromatography silica gel and stir, and stir thoroughly until a uniform gel is formed; wherein the molar ratio of the active ingredients SiO2, template, NaOH, Al2O3 and H2O in the gel is 1:0.02:0.58:0.006:7.5, and the mass of the seed crystal is 3% of the mass of SiO2;

[0149] The gel was placed in an oven at 150° C. for crystallization for 5 days. The obtained product was centrifuged, dried at 90° C., and then calcined at 600° C. for 5 h to obtain SSZ-39 molecular sieve (denoted as S23).

[0150] Embodiment 24

[0151] Add the template, distilled water, sodium hydroxide and SAPO-KFI seed crystals into a reaction container, stir evenly under closed and room temperature conditions, then add column chromatography silica gel and stir, and stir thoroughly until a uniform gel is formed; wherein the molar ratio of the active ingredients SiO2, template, NaOH, Al2O3 and H2O in the gel is 1:0.02:0.58:0.006:7.5, and the mass of the seed crystal is 3% of the mass of SiO2;

[0152] The gel was placed in an oven at 150°C for crystallization for 5 days. The obtained product was centrifuged, dried at 90°C, and then calcined at 600°C for 5 hours to obtain SSZ-39 molecular sieve (denoted as S24).

[0153] Figure 5 The XRD patterns of the SSZ-39 molecular sieves (S3, S20-S24) prepared in Example 3 and Examples 20-24 are shown in FIG. Figure 5 It can be seen that all small-pore SAPO molecular sieve seeds can synthesize SSZ-39 molecular sieve.

[0154] Comparative Example 1

[0155] The molecular sieve product was synthesized with reference to Example 3, except that H-SSZ-39 molecular sieve was used as the seed crystal, as follows:

[0156] H-SSZ-39 molecular sieve with a silicon-to-aluminum ratio of 5 was used as seed crystal, and 1%, 2%, 3%, 4%, 5% and 6% of the silicon source mass (in terms of SiO2) were added respectively, wherein the molar ratio of the effective ingredients SiO2, template, NaOH, Al2O3 and H2O in the gel was 1:0.02:0.58:0.006:7.5, and the insufficient aluminum was supplemented with aluminum sulfate; the obtained molecular sieve products were recorded as S25, S26, S27, S28, S29 and S30 respectively.

[0157] Figure 6 The XRD diagram of the molecular sieve (S25-S30) prepared in Comparative Example 1 is shown in FIG. Figure 6 It can be seen that under this gel ratio, SSZ-39 molecular sieve cannot be synthesized when silica-alumina molecular sieve is used as seed.

[0158] Comparative Example 2

[0159] For comparison, a document published in the authoritative journal ACS Applied Materials & Interfaces (ACS Appl. Mater. Interfaces 2019, 11, 26, 23112–23117) calculated the cost of synthesizing 1 ton of sample based on the market price of raw materials. Its mold-to-silicon ratio is 0.12, sodium aluminate is used as the aluminum source, and the yield is only 21%. After calculation, its cost is 364,000 yuan / ton, more than double the cost of the present invention.

[0160] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be regarded as the protection scope of the present invention.

Claims

1. A method for preparing a pan-silicon-aluminum ratio SSZ-39 molecular sieve, characterized in that: The following steps are involved: The template, water, alkali source, seed crystal and silicon source are mixed to obtain a gel; the alkali source is an alkali metal hydroxide, and the seed crystal is a small-pore SAPO molecular sieve; the composition of the gel satisfies the molar ratio of SiO2: template: alkali metal hydroxide: Al2O3: H2O = 1: 0.02: 0.58: 0.002-0.012: 7.5, wherein the molar amount of SiO2 is obtained by converting the silicon element in the silicon source to SiO2, and the molar amount of Al2O3 is obtained by converting the aluminum element in the seed crystal to Al2O3; performing hydrothermal crystallization on the gel to obtain a crystallized product; The crystallized product is calcined to obtain SSZ-39 molecular sieve.

2. The method according to claim 1, characterized in that The template agent is 1,1,3,5-tetramethylpiperidinium hydroxide.

3. The method according to claim 1, characterized in that The alkali source is sodium hydroxide and / or potassium hydroxide.

4. The method according to claim 1, characterized in that The silicon source is one or more of silica gel, silica sol and white carbon black.

5. The method according to claim 1, characterized in that The small-pore SAPO molecular sieve is one or more of AEI SAPO molecular sieve, CHA SAPO molecular sieve, LEV SAPO molecular sieve, RHO SAPO molecular sieve, ERI SAPO molecular sieve and KFI SAPO molecular sieve.

6. The method according to claim 1, characterized in that The temperature of the hydrothermal crystallization is 130-160° C., and the time is 1-5 days.

7. The method according to claim 1 or 6, characterized in that: After the hydrothermal crystallization, the method further includes sequentially performing solid-liquid separation and drying on the obtained crystallization reaction liquid to obtain the crystallized product.

8. The method according to claim 1, characterized in that The calcination temperature is 550-750° C. and the calcination time is 4-10 hours.

9. The method according to claim 1, characterized in that: The silicon-aluminum molar ratio of the SSZ-39 molecular sieve is 7-19.

10. The method according to claim 1, characterized in that After the calcination, the method further includes sequentially exchanging ammonium ions and calcining the calcined molecular sieve to obtain a hydrogen-type SSZ-39 molecular sieve.

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