CN115321555A - A kind of method for synthesizing high silicon AFX zeolite molecular sieve with small molecule organic template - Google Patents

Abstract

The invention discloses a method for synthesizing a high-silicon AFX zeolite molecular sieve by using a small-molecular organic template. The invention utilizes a series of simple and cheap small molecular organic templates to synthesize the high-silicon AFX zeolite molecular sieve, the silicon-aluminum ratio of the product obtained by the method can be about 7, and the method is very suitable for NH ₃ -SCR reaction and the obtained product has very excellent hydrothermal stability, maintaining its basic structure even after 16 hours of hydrothermal aging at 850 ℃; the micromolecular organic template agent used in the method has simple structure and low price, greatly reduces the synthesis cost, and solves the problem that the silicon-aluminum ratio of the conventional AFX zeolite molecular sieve is not higher than 5 (Si/Al)<5.0 Poor hydrothermal stability or high production cost caused by the use of a template agent with high price; for the industrial production of AFX zeolite molecular sieves and as a new generation of NH ₃ SCR catalyst offers the possibility.

Description

A method for synthesizing high-silicon AFX zeolite molecular sieves with a small molecule organic template

technical field

The invention relates to a method for synthesizing a high-silicon AFX zeolite molecular sieve with a small-molecule organic template agent, and belongs to the technical field of molecular sieves.

technical background

AFX molecular sieves belong to the ABC family, and its skeleton structure is mainly composed of d6r arranged in the order of AABBCCBB to form a three-dimensional eight-membered ring channel structure and has a larger aft cage (0.55×1.35nm) and a slightly smaller gme cage (0.34×0.66nm). The molecular sieve was originally discovered with an aluminum phosphate structure, and Wilson et al. named it SAPO-56 molecular sieve. Subsequently, Zones et al. successfully synthesized AFX with a silicon-aluminum structure using the double-ended quaternary ammonium salt 1,4-bis(1-azoniabicyclo[2.2.2]octane)butyl dibromide as an organic template, and named it SSZ-16 zeolite molecular sieve . The Cu ²⁺ exchanged SSZ-16 zeolite molecular sieve exhibited excellent NO _x conversion in NO _x selective catalytic reduction reaction (NH ₃ -SCR). However, since the silicon-aluminum ratio of the SSZ-16 zeolite molecular sieve product is not higher than 5 (Si/Al<5.0), its hydrothermal stability is poor, and it usually loses its activity completely after hydrothermal aging at 800°C for 16 hours. Subsequently, Zones et al. developed a new method for synthesizing SSZ-16 with 1,3-bis(1-adamantyl)imidazoliumbromide as an organic template. The product obtained by this method has a silicon-aluminum ratio of up to 17 and is weakly acidic and inapplicable. In NH ₃ -SCR reaction. Corma et al. synthesized nano-sized high-silicon SSZ-16 (Si/Al=5.2-5.3) by using a large-sized rigid double-headed quaternary ammonium salt as an organic template through the high-silicon USY crystallization method. Organic templates are complex and expensive, and difficult to synthesize.

Therefore, in order to better develop the application of AFX in NH ₃ -SCR reaction, it is necessary to develop a simple and efficient synthesis of high-silica AFX zeolite molecular sieve suitable for NH ₃ -SCR reaction.

Contents of the invention

The technical problem to be solved by the present invention is: the current AFX zeolite molecular sieve has a low silicon-aluminum ratio (Si/Al<5.0), poor hydrothermal stability, high production cost due to the use of expensive templates or is not suitable for NH ₃ -Technical issues such as SCR response.

In order to achieve the above object, the present invention provides a method for synthesizing high-silicon AFX zeolite molecular sieves with a small molecular organic template, comprising: at first silicon-aluminum source, sodium hydroxide solid, organic template OSDA (OH) ₂ aqueous solution and water according to Molar ratio SiO ₂ :Al ₂ O ₃ :Na ₂ O:OSDA(OH) ₂ :H ₂ O＝25-72:1:0.6-16:5-18:500-3000, stirring to form a gel Transfer to a reaction kettle for crystallization reaction, after the reaction is completed, the reaction product is washed and dried to obtain a high-silicon AFX zeolite molecular sieve with a silicon-aluminum atomic ratio of 5.0-7.1; wherein, the organic template in the aqueous solution of the organic template The templating agent is N,N'-dimethyl-N,N,N',N'-tetraethyl-1,6-hexamethylene diammonium hydroxide, N,N,N',N'-tetramethyl- N,N'-Diethyl-1,6-Hexammonium Hydroxide, N,N,N',N'-Tetramethyl-N,N'-Diisopropyl-1,6-Hexyl Hydroxide Diammonium, N,N-dimethyl-N,N′,N′,N′-tetraethyl-1,6-hexamethylenediammonium hydroxide and N,N,N′-trimethyl-N,N At least one of ',N'-triethyl-1,6-hexamethylenediammonium hydroxide.

Preferably, the preparation method of the organic template aqueous solution comprises: dissolving trialkylamine R ₁ N(R ₂ ) ₂ and 1,6-dibromohexane in acetonitrile in proportion, heating to reflux and stirring for reaction; after the reaction is completed , filter the reaction product with suction and rinse with acetonitrile; after vacuum drying, exchange with a hydroxide type anion exchange resin to obtain a certain concentration of an organic template aqueous solution; wherein, the trialkylamine R ₁ N(R ₂ ) ₂ is N, At least one of N-diethylmethylamine, N,N-dimethylethylamine, N,N-dimethylisopropylamine and triethylamine.

Preferably, the silicon-aluminum source is a combination of silicon source and aluminum source, and/or USY molecular sieve, ZSM-5 molecular sieve, ZSM-22 molecular sieve, ZSM-23 molecular sieve, ZSM-11 molecular sieve, MCM-22 molecular sieve and FER( At least one of ZSM-35) molecular sieves, the silicon source is selected from silica sol and/or tetraethyl silicate (TEOS), and the aluminum source is selected from sodium metaaluminate, aluminum hydroxide, octadecadecanoic sulfuric acid at least one of aluminum and aluminum isopropoxide.

Preferably, the temperature of the crystallization reaction is 140-160° C., and the time is 1-5 days.

The present invention also provides the high-silicon AFX zeolite molecular sieve prepared by the method for synthesizing the high-silicon AFX zeolite molecular sieve with the above-mentioned small molecule organic template agent.

The present invention also provides a Cu-AFX catalyst, which is prepared by sequentially calcination, ammonium ion exchange, Cu ²⁺ ion exchange and secondary calcination of the above-mentioned high-silicon AFX zeolite molecular sieve.

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

1. The method for synthesizing high-silicon AFX zeolite molecular sieves with the small molecule organic template agent of the present invention, the organic template agent used is simple in structure, low in price, greatly reduces production costs, and the method yield of the present invention is high, and can be used in actual chemical production area is of great importance;

2. The silicon-aluminum ratio of the high-silicon AFX zeolite molecular sieve synthesized by the present invention can be about 7. The product of this silicon-alumina ratio is very suitable for NH ₃ -SCR reaction, and the product has good hydrothermal stability, even at 10% Under water and air conditions, it can still maintain its basic structure after hydrothermal aging at 850°C for 16 hours, so it can be used as a new generation of NH ₃ -SCR catalyst with high hydrothermal stability.

Description of drawings

Fig. 1 is the XRD spectrogram of the high silicon AFX zeolite molecular sieve product that embodiment 1 synthesizes;

Fig. 2 is the scanning electron micrograph of the high silicon AFX zeolite molecular sieve product that embodiment 1 synthesizes;

Fig. 3 is the XRD spectrogram of the AFX molecular sieve product synthesized by different silicon-aluminum sources in Examples 2-8;

Fig. 4 is the XRD spectrum of the AFX molecular sieve product synthesized by different organic templates in Examples 13-16.

Detailed ways

In order to make the present invention more comprehensible, preferred embodiments are described in detail below with accompanying drawings.

In the following examples, the synthetic method of the organic template used is as follows:

N,N′-dimethyl-N,N,N′,N′-tetraethyl-1,6-hexamethylenediammonium hydroxide (OSDA1(OH) ₂ ): N,N-diethylmethylamine and 1,6-Dibromohexane was dissolved in acetonitrile in proportion and heated, condensed and stirred for 1 day; aqueous templating agent.

N,N,N′,N′-tetramethyl-N,N′-diethyl-1,6-hexamethylenediammonium hydroxide (OSDA2(OH) ₂ ): N,N-dimethylethylamine and 1,6-Dibromohexane was dissolved in acetonitrile in proportion and heated to reflux and stirred for 1 day; after the reaction was completed, the reaction product was suction-filtered and rinsed with a large amount of acetonitrile; after vacuum drying, it was exchanged with a hydroxide-type anion exchange resin to obtain a certain concentration of organic aqueous templating agent.

N,N,N′,N′-tetramethyl-N,N′-diisopropyl-1,6-hexamethylenediammonium hydroxide (OSDA3(OH) ₂ ): N,N-dimethylisopropylamine and 1,6-Dibromohexane was dissolved in acetonitrile in proportion and heated to reflux and stirred for 1 day; after the reaction was completed, the reaction product was suction-filtered and rinsed with a large amount of acetonitrile; after vacuum drying, it was exchanged with a hydroxide-type anion exchange resin to obtain a certain concentration of organic aqueous templating agent.

N,N-Dimethyl-N,N′,N′,N′-tetraethyl-1,6-hexamethylenediammonium hydroxide (OSDA4(OH) ₂ ): N,N-dimethylethylamine, Triethylamine and 1,6-dibromohexane were dissolved in acetonitrile in proportion and heated to reflux and stirred for 1 day; after the reaction was completed, the reaction product was suction-filtered and rinsed with a large amount of acetonitrile; after vacuum drying, it was exchanged with a hydroxide-type anion exchange resin to obtain A certain concentration of organic template agent aqueous solution.

N,N,N'-trimethyl-N,N',N'-triethyl-1,6-hexamethylenediammonium hydroxide (OSDA5(OH) ₂ ): N,N-diethylmethylamine, N,N-dimethylethylamine and 1,6-dibromohexane were dissolved in acetonitrile in proportion and heated to reflux and stirred for 1 day; after the reaction was completed, the reaction product was suction filtered and rinsed with a large amount of acetonitrile; Type anion exchange resin exchange to obtain a certain concentration of organic template agent aqueous solution.

Example 1

First, add a certain amount of sodium hydroxide, OSDA1(OH) ₂ solution (0.53M) and high-stable Y molecular sieve (USY molecular sieve, Si/Al=12.5) to an appropriate amount of water, stir for 2 to 3 hours to form a uniform gel The reaction raw materials were transferred to a polytetrafluoroethylene stainless steel reactor, and crystallized at 160°C for 2.5 days to complete crystallization. After the reaction was completed, the reaction product was washed with deionized water and dried at 80°C for more than 12 hours. The molar ratio of the reaction raw materials is as follows: 25SiO ₂ : 1Al ₂ O ₃ : 2Na ₂ O: 6OSDA(OH) ₂ : 1000H ₂ O; the silicon-aluminum ratio of the final high-silica AFX zeolite molecular sieve is 7.1.

According to X-ray diffraction analysis, it is an AFX zeolite molecular sieve (Figure 1), and it can be seen from the scanning electron microscope photo (Figure 2) that the synthesized product presents a spindle-shaped block.

Example 2

Add a certain amount of sodium hydroxide, OSDA1(OH) ₂ solution (0.53M) and ZSM-5 molecular sieve (Si/Al=15) to an appropriate amount of water, stir for 2-3 hours to form a uniform gel, and then transfer the reaction materials to In a polytetrafluoroethylene stainless steel reactor, crystallize at 160°C for 2.5 days to complete crystallization. After the reaction is completed, the reaction product is washed with deionized water and dried at 80°C for more than 12 hours. The molar ratio of the reaction raw materials is as follows: 30SiO ₂ : 1Al ₂ O ₃ : 4Na ₂ O: 8OSDA(OH) ₂ : 1200H ₂ O; the silicon-aluminum ratio of the final high-silicon AFX zeolite molecular sieve is 5.2.

Example 3

Add a certain amount of sodium hydroxide, OSDA1(OH) ₂ solution (0.53M) and ZSM-22 molecular sieve (Si/Al=35.8) to an appropriate amount of water, stir for 2-3 hours to form a uniform gel, and then transfer the reaction materials to In a polytetrafluoroethylene stainless steel reactor, crystallize at 160°C for 2.5 days to complete crystallization. After the reaction is completed, the reaction product is washed with deionized water and dried at 80°C for more than 12 hours. The molar ratio of the reaction raw materials is as follows: 72SiO ₂ : 1Al ₂ O ₃ : 16Na ₂ O: 18OSDA(OH) ₂ : 3000H ₂ O; the silicon-aluminum ratio of the final high-silicon AFX zeolite molecular sieve is 5.2.

Example 4

Add a certain amount of sodium hydroxide, OSDA1(OH) ₂ solution (0.53M) and ZSM-23 (Si/Al=33) to an appropriate amount of water, stir for 2-3 hours to form a uniform gel, and then transfer the reaction materials to the polymer In a tetrafluoroethylene stainless steel reaction kettle, crystallize at 160°C for 2.5 days to complete crystallization. After the reaction is completed, the reaction product is washed with deionized water and dried at 80°C for more than 12 hours. The molar ratio of the reaction raw materials is as follows: 66SiO ₂ : 1Al ₂ O ₃ : 15Na ₂ O: 17OSDA(OH) ₂ : 2600H ₂ O; the silicon-aluminum ratio of the final high-silicon AFX zeolite molecular sieve is 5.2.

Example 5

Add a certain amount of sodium hydroxide, OSDA1 (OH) ₂ solution (0.53M) and MCM-22 (Si/Al = 13.4) to an appropriate amount of water, stir for 2-3 hours to form a uniform gel, and then transfer the reaction materials to the polymer In a tetrafluoroethylene stainless steel reaction kettle, crystallize at 160°C for 2.5 days to complete crystallization. After the reaction is completed, the reaction product is washed with deionized water and dried at 80°C for more than 12 hours. The molar ratio of the reaction raw materials is as follows: 27SiO ₂ : 1Al ₂ O ₃ : 3Na ₂ O: 6OSDA(OH) ₂ : 1100H ₂ O; the silicon-aluminum ratio of the final high-silicon AFX zeolite molecular sieve is 5.5.

Example 6

Add a certain amount of sodium hydroxide, OSDA1(OH) ₂ solution (0.53M) and FER (Si/Al=30) to an appropriate amount of water, stir for 2-3 hours to form a uniform gel, and then transfer the reaction materials to polytetrafluoroethylene In an ethylene stainless steel reactor, crystallize at 160°C for 2.5 days to complete crystallization. After the reaction is completed, the reaction product is washed with deionized water and dried at 80°C for more than 12 hours. The molar ratio of the reaction raw materials is as follows: 60SiO ₂ : 1Al ₂ O ₃ : 13Na ₂ O: 15OSDA(OH) ₂ : 2400H ₂ O; the silicon-aluminum ratio of the final high-silicon AFX zeolite molecular sieve is 5.5.

Example 7

Add a certain amount of sodium hydroxide, OSDA1 (OH) ₂ solution (0.53M) and ZSM-11 (Si/Al = 33.1) to an appropriate amount of water, stir for 2-3 hours to form a uniform gel, and then transfer the reaction materials to the polymer In a tetrafluoroethylene stainless steel reaction kettle, crystallize at 160°C for 2.5 days to complete crystallization. After the reaction is completed, the reaction product is washed with deionized water and dried at 80°C for more than 12 hours. The molar ratio of the reaction raw materials is as follows: 66SiO ₂ : 1Al ₂ O ₃ : 15Na ₂ O: 17OSDA(OH) ₂ : 2700H ₂ O; the silicon-aluminum ratio of the final high-silicon AFX zeolite molecular sieve is 5.2.

Example 8

Add a certain amount of sodium hydroxide, sodium metaaluminate, OSDA1(OH) ₂ solution (0.53M) and silica sol (mass fraction 40%) into an appropriate amount of water, and after stirring for 2 to 3 hours, transfer the reaction materials to polytetrafluoroethylene In the vinyl fluoride stainless steel reactor, crystallize at 160°C for 2.5 days to complete crystallization. After the reaction is completed, the reaction product is washed with deionized water and dried at 80°C for more than 12 hours. The molar ratio of the reaction raw materials is as follows: 25SiO ₂ : 1Al ₂ O ₃ : 2Na ₂ O: 6OSDA(OH) ₂ : 1000H ₂ O; the silicon-aluminum ratio of the final high-silica AFX zeolite molecular sieve is 7.1.

Example 9

Add a certain amount of sodium hydroxide, aluminum hydroxide, OSDA1(OH) ₂ solution (0.53M) and silica sol (mass fraction 40%) into an appropriate amount of water, crystallize at 160°C for 2.5 days and complete crystallization, the reaction is complete Afterwards, the reaction product was washed with deionized water and dried at 80 °C for more than 12 hours. The molar ratio of the reaction raw materials is as follows: 25SiO ₂ : 1Al ₂ O ₃ : 6Na ₂ O: 6OSDA(OH) ₂ : 1000H ₂ O; the silicon-aluminum ratio of the final high-silicon AFX zeolite molecular sieve is 7.1.

Example 10

Add a certain amount of sodium hydroxide, aluminum isopropoxide, OSDA1(OH) ₂ solution (0.53M) and silica sol (mass fraction 40%) into an appropriate amount of water, crystallize at 160°C for 2.5 days and complete crystallization, the reaction is complete Afterwards, the reaction product was washed with deionized water and dried at 80 °C for more than 12 hours. The molar ratio of the reaction raw materials is as follows: 25SiO ₂ : 1Al ₂ O ₃ : 6Na ₂ O: 6OSDA(OH) ₂ : 1000H ₂ O; the silicon-aluminum ratio of the final high-silicon AFX zeolite molecular sieve is 7.1.

Example 11

Add a certain amount of sodium hydroxide, aluminum sulfate octadecahydrate, OSDA1(OH) ₂ solution (0.53M) and silica sol (mass fraction 40%) into an appropriate amount of water, and crystallize at 160°C for 2.5 days to completely crystallize, and react After completion, the reaction product was washed with deionized water and dried at 80 °C for more than 12 hours. The molar ratio of the reaction raw materials is as follows: 25SiO ₂ : 1Al ₂ O ₃ : 6Na ₂ O: 6OSDA(OH) ₂ : 1000H ₂ O; the silicon-aluminum ratio of the final high-silicon AFX zeolite molecular sieve is 7.1.

Example 12

Add a certain amount of sodium hydroxide, aluminum sulfate octadecahydrate, OSDA1(OH) ₂ solution (0.53M) and tetraethyl silicate (TEOS) into an appropriate amount of water, and crystallize at 160°C for 2.5 days to completely crystallize, and react After completion, the reaction product was washed with deionized water and dried at 80 °C for more than 12 hours. The molar ratio of the reaction raw materials is as follows: 25SiO ₂ : 1Al ₂ O ₃ : 6Na ₂ O: 6OSDA(OH) ₂ : 1000H ₂ O; the silicon-aluminum ratio of the final high-silicon AFX zeolite molecular sieve is 7.1.

Example 13

Add a certain amount of sodium hydroxide, OSDA2(OH) ₂ solution (0.75M) and high stability Y (Si/Al=12.5) to an appropriate amount of water, stir for 2-3 hours to form a uniform gel, and then transfer the reaction materials to the poly In a tetrafluoroethylene stainless steel reaction kettle, crystallize at 160°C for 3 days to complete crystallization. After the reaction is completed, the reaction product is washed with deionized water and dried at 80°C for more than 12 hours. The molar ratio of the reaction raw materials is as follows: 25SiO ₂ : 1Al ₂ O ₃ : 1Na ₂ O: 6OSDA(OH) ₂ : 1000H ₂ O; the silicon-aluminum ratio of the final high-silica AFX zeolite molecular sieve is 7.1.

Example 14

Add a certain amount of sodium hydroxide, OSDA3(OH) ₂ solution (0.51M) and high stability Y (Si/Al=12.5) to an appropriate amount of water, stir for 2-3 hours to form a uniform gel, and then transfer the reaction materials to the poly In a tetrafluoroethylene stainless steel reaction kettle, crystallize at 160°C for 3 days to complete crystallization. After the reaction is completed, the reaction product is washed with deionized water and dried at 80°C for more than 12 hours. The molar ratio of the reaction raw materials is as follows: 25SiO ₂ : 1Al ₂ O ₃ : 4Na ₂ O: 6OSDA(OH) ₂ : 1000H ₂ O; the silicon-aluminum ratio of the final high-silicon AFX zeolite molecular sieve is 7.1.

Example 15

Add a certain amount of sodium hydroxide, OSDA4(OH) ₂ solution (0.53M) and high stability Y (Si/Al=12.5) to an appropriate amount of water, stir for 2-3 hours to form a uniform gel, and then transfer the reaction materials to the polymer In a tetrafluoroethylene stainless steel reaction kettle, crystallize at 160°C for 3 days to complete crystallization. After the reaction is completed, the reaction product is washed with deionized water and dried at 80°C for more than 12 hours. The molar ratio of the reaction raw materials is as follows: 25SiO ₂ : 1Al ₂ O ₃ : 1Na ₂ O: 6OSDA(OH) ₂ : 1000H ₂ O; the silicon-aluminum ratio of the final high-silica AFX zeolite molecular sieve is 7.1.

Example 16

Add a certain amount of sodium hydroxide, OSDA5(OH) ₂ solution (0.55M) and high-stable Y (Si/Al=12.5) to an appropriate amount of water, stir for 2-3 hours to form a uniform gel, and then transfer the reaction materials to the polymer In a tetrafluoroethylene stainless steel reaction kettle, crystallize at 160°C for 3 days to complete crystallization. After the reaction is completed, the reaction product is washed with deionized water and dried at 80°C for more than 12 hours. The molar ratio of the reaction raw materials is as follows: 25SiO ₂ : 1Al ₂ O ₃ : 1Na ₂ O: 6OSDA(OH) ₂ : 1000H ₂ O; the silicon-aluminum ratio of the final high-silica AFX zeolite molecular sieve is 7.1.

Example 17

Add a certain amount of sodium hydroxide, OSDA1(OH) ₂ solution (0.53M) and high-stable Y (Si/Al=12.5) to an appropriate amount of water, stir for 2-3 hours to form a uniform gel, and then transfer the reaction materials to the polymer In a tetrafluoroethylene stainless steel reaction kettle, crystallize at 160°C for 2.5 days to complete crystallization. After the reaction is completed, the reaction product is washed with deionized water and dried at 80°C for more than 12 hours. The molar ratio of the reaction raw materials is as follows: 25SiO ₂ : 1Al ₂ O ₃ : 0.6Na ₂ O: 6OSDA(OH) ₂ : 1000H ₂ O; the silicon-aluminum ratio of the final high-silicon AFX zeolite molecular sieve is 7.1.

Example 18

Add a certain amount of sodium hydroxide, OSDA1(OH) ₂ solution (0.53M) and high-stable Y (Si/Al=12.5) to an appropriate amount of water, stir for 2-3 hours to form a uniform gel, and then transfer the reaction materials to the polymer In a tetrafluoroethylene stainless steel reaction kettle, crystallize at 160°C for 2.5 days to complete crystallization. After the reaction is completed, the reaction product is washed with deionized water and dried at 80°C for more than 12 hours. The molar ratio of the reaction raw materials is as follows: 25SiO ₂ : 1Al ₂ O ₃ : 1Na ₂ O: 6OSDA(OH) ₂ : 1000H ₂ O; the silicon-aluminum ratio of the final high-silica AFX zeolite molecular sieve is 7.1.

Example 19

Add a certain amount of sodium hydroxide, OSDA1(OH) ₂ solution (0.53M) and high-stable Y (Si/Al=12.5) to an appropriate amount of water, stir for 2-3 hours to form a uniform gel, and then transfer the reaction materials to the polymer In a tetrafluoroethylene stainless steel reaction kettle, crystallize at 160°C for 2.5 days to complete crystallization. After the reaction is completed, the reaction product is washed with deionized water and dried at 80°C for more than 12 hours. The molar ratio of the reaction raw materials is as follows: 25SiO ₂ : 1Al ₂ O ₃ : 3Na ₂ O: 6OSDA(OH) ₂ : 1000H ₂ O; the silicon-aluminum ratio of the final high-silicon AFX zeolite molecular sieve is 6.5.

Example 20

Add a certain amount of sodium hydroxide, OSDA1(OH) ₂ solution (0.53M) and high-stable Y (Si/Al=12.5) to an appropriate amount of water, stir for 2-3 hours to form a uniform gel, and then transfer the reaction materials to the polymer In a tetrafluoroethylene stainless steel reaction kettle, crystallize at 160°C for 2.5 days to complete crystallization. After the reaction is completed, the reaction product is washed with deionized water and dried at 80°C for more than 12 hours. The molar ratio of the reaction raw materials is as follows: 25SiO ₂ : 1Al ₂ O ₃ : 4Na ₂ O: 6OSDA(OH) ₂ : 1000H ₂ O; the silicon-aluminum ratio of the final high-silicon AFX zeolite molecular sieve is 5.8.

Example 21

Add a certain amount of sodium hydroxide, OSDA1(OH) ₂ solution (0.53M) and high-stable Y (Si/Al=12.5) to an appropriate amount of water, stir for 2-3 hours to form a uniform gel, and then transfer the reaction materials to the polymer In a tetrafluoroethylene stainless steel reaction kettle, crystallize at 160°C for 2.5 days to complete crystallization. After the reaction is completed, the reaction product is washed with deionized water and dried at 80°C for more than 12 hours. The molar ratio of the reaction raw materials is as follows: 25SiO ₂ : 1Al ₂ O ₃ : 2Na ₂ O: 5OSDA(OH) ₂ : 1000H ₂ O; the silicon-aluminum ratio of the final high-silicon AFX zeolite molecular sieve is 6.8.

Example 22

Add a certain amount of sodium hydroxide, OSDA1(OH) ₂ solution (0.53M) and high-stable Y (Si/Al=12.5) to an appropriate amount of water, stir for 2-3 hours to form a uniform gel, and then transfer the reaction materials to the polymer In a tetrafluoroethylene stainless steel reaction kettle, crystallize at 160°C for 2.5 days to complete crystallization. After the reaction is completed, the reaction product is washed with deionized water and dried at 80°C for more than 12 hours. The molar ratio of the reaction raw materials is as follows: 25SiO ₂ : 1Al ₂ O ₃ : 2Na ₂ O: 8OSDA(OH) ₂ : 1000H ₂ O; the silicon-aluminum ratio of the final high-silicon AFX zeolite molecular sieve is 7.1.

Example 23

Add a certain amount of sodium hydroxide, OSDA1(OH) ₂ solution (0.53M) and high-stable Y (Si/Al=12.5) to an appropriate amount of water, stir for 2-3 hours to form a uniform gel, and then transfer the reaction materials to the polymer Tetrafluoroethylene stainless steel reactor, and dried at 80 ℃ for more than 12 hours. The molar ratio of the reaction raw materials is as follows: 25SiO ₂ : 1Al ₂ O ₃ : 2Na ₂ O: 10OSDA(OH) ₂ : 1000H ₂ O; the silicon-aluminum ratio of the final high-silicon AFX zeolite molecular sieve is 7.1.

Example 24

Add a certain amount of sodium hydroxide, OSDA1(OH) ₂ solution (0.53M) and high-stable Y (Si/Al=12.5) to an appropriate amount of water, stir for 2-3 hours to form a uniform gel, and then transfer the reaction materials to the polymer In a tetrafluoroethylene stainless steel reaction kettle, crystallize at 160°C for 2.5 days to complete crystallization. After the reaction is completed, the reaction product is washed with deionized water and dried at 80°C for more than 12 hours. The molar ratio of the reaction raw materials is as follows: 25SiO ₂ : 1Al ₂ O ₃ : 2Na ₂ O: 6OSDA(OH) ₂ : 500H ₂ O; the silicon-aluminum ratio of the final high-silicon AFX zeolite molecular sieve is 7.1.

Example 25

Add a certain amount of sodium hydroxide, OSDA1(OH) ₂ solution (0.53M) and high-stable Y (Si/Al=12.5) to an appropriate amount of water, stir for 2-3 hours to form a uniform gel, and then transfer the reaction materials to the polymer In a tetrafluoroethylene stainless steel reaction kettle, crystallize at 160°C for 2.5 days to complete crystallization. After the reaction is completed, the reaction product is washed with deionized water and dried at 80°C for more than 12 hours. The molar ratio of the reaction raw materials is as follows: 25SiO ₂ : 1Al ₂ O ₃ : 2Na ₂ O: 6OSDA(OH) ₂ : 750H ₂ O; the silicon-aluminum ratio of the final high-silica AFX zeolite molecular sieve is 7.1.

Example 26

Add a certain amount of sodium hydroxide, OSDA1(OH) ₂ solution (0.53M) and high-stable Y (Si/Al=12.5) to an appropriate amount of water, stir for 2-3 hours to form a uniform gel, and then transfer the reaction materials to the polymer In a tetrafluoroethylene stainless steel reaction kettle, crystallize at 160°C for 2.5 days to complete crystallization. After the reaction is completed, the reaction product is washed with deionized water and dried at 80°C for more than 12 hours. The molar ratio of the reaction raw materials is as follows: 32SiO ₂ : 1Al ₂ O ₃ : 2Na ₂ O: 8OSDA(OH) ₂ : 1300H ₂ O; the silicon-aluminum ratio of the final high-silica AFX zeolite molecular sieve is 7.1.

Example 27

Add a certain amount of sodium hydroxide, OSDA1(OH) ₂ solution (0.53M) and high-stable Y (Si/Al=12.5) to an appropriate amount of water, stir for 2-3 hours to form a uniform gel, and then transfer the reaction materials to the polymer In a tetrafluoroethylene stainless steel reaction kettle, crystallize at 160°C for 2.5 days to complete crystallization. After the reaction is completed, the reaction product is washed with deionized water and dried at 80°C for more than 12 hours. The molar ratio of the reaction raw materials is as follows: 60SiO ₂ : 1Al ₂ O ₃ : 5Na ₂ O: 15OSDA(OH) ₂ : 2400H ₂ O; the silicon-aluminum ratio of the final high-silica AFX zeolite molecular sieve is 7.1.

Example 28

Add a certain amount of sodium hydroxide, OSDA1(OH) ₂ solution (0.53M) and high-stable Y (Si/Al=12.5) to an appropriate amount of water, stir for 2-3 hours to form a uniform gel, and then transfer the reaction materials to the polymer In a tetrafluoroethylene stainless steel reaction kettle, crystallize at 160°C for 1 day. After the reaction is completed, the reaction product is washed with deionized water and dried at 80°C for more than 12 hours. The molar ratio of the reaction raw materials is as follows: 25SiO ₂ : 1Al ₂ O ₃ : 2Na ₂ O: 6OSDA(OH) ₂ : 1000H ₂ O; the silicon-aluminum ratio of the final high-silica AFX zeolite molecular sieve is 7.1.

Example 29

Add a certain amount of sodium hydroxide, OSDA1(OH) ₂ solution (0.53M) and high-stable Y (Si/Al=12.5) to an appropriate amount of water, stir for 2-3 hours to form a uniform gel, and then transfer the reaction materials to the polymer In a tetrafluoroethylene stainless steel reaction kettle, crystallize at 160°C for 2 days. After the reaction is completed, the reaction product is washed with deionized water and dried at 80°C for more than 12 hours. The molar ratio of the reaction raw materials is as follows: 25SiO ₂ : 1Al ₂ O ₃ : 2Na ₂ O: 6OSDA(OH) ₂ : 1000H ₂ O; the silicon-aluminum ratio of the final high-silica AFX zeolite molecular sieve is 7.1.

Example 30

Add a certain amount of sodium hydroxide, OSDA1(OH) ₂ solution (0.53M) and high-stable Y (Si/Al=12.5) to an appropriate amount of water, stir for 2-3 hours to form a uniform gel, and then transfer the reaction materials to the polymer In a tetrafluoroethylene stainless steel reaction kettle, crystallize at 140°C for 5 days to complete crystallization. After the reaction is completed, the reaction product is washed with deionized water and dried at 80°C for more than 12 hours. The molar ratio of the reaction raw materials is as follows: 25SiO ₂ : 1Al ₂ O ₃ : 2Na ₂ O: 6OSDA(OH) ₂ : 1000H ₂ O; the silicon-aluminum ratio of the final high-silica AFX zeolite molecular sieve is 7.1.

Example 31

Add a certain amount of sodium hydroxide, OSDA1(OH) ₂ solution (0.53M) and high-stable Y (Si/Al=12.5) to an appropriate amount of water, stir for 2-3 hours to form a uniform gel, and then transfer the reaction materials to the polymer In a tetrafluoroethylene stainless steel reaction kettle, crystallize at 150°C for 4 days to complete crystallization. After the reaction is completed, the reaction product is washed with deionized water and dried at 80°C for more than 12 hours. The molar ratio of the reaction raw materials is as follows: 25SiO ₂ : 1Al ₂ O ₃ : 2Na ₂ O: 6OSDA(OH) ₂ : 1000H ₂ O; the silicon-aluminum ratio of the final high-silica AFX zeolite molecular sieve is 7.1.

performance measurement

Get the zeolite molecular sieve of 0.5g embodiment 1, and the AFX zeolite molecular sieve that is 3.5 is roasted in the muffle furnace under the air condition of 600 ℃ as the conventional silicon-aluminum ratio of comparison sample; Carry out ammonium ion exchange, then filter, wash and dry; repeat 2 to 3 times to complete ammonium ion exchange; add the molecular sieve that has completed ammonium ion exchange to 0.05mol/L copper nitrate solution, and stir at 40°C for 6 Hours; filtered, washed, dried, and then transferred to a muffle furnace, baked at 550 ° C under air conditions for 5 hours to obtain the Cu-AFX catalyst and the comparison sample Cu-AFX-con. The mass content of copper ions is 2.5-3.5%. Sieve the catalyst into 40-60 mesh size particles for later use.

Get 0.2g of sieved Cu-AFX catalyst and comparative sample Cu-AFX-con, and carry out hydrothermal treatment in a tubular fixed-bed reactor respectively: under 10% water and air conditions, 850 ° C for 16 hours; after treatment Cool to room temperature. The crystallinity (100%) of the catalyst after the hydrothermal treatment relative to the catalyst before the hydrothermal treatment is as follows:

Sample serial number Relative crystallinity% Cu-AFX catalyst 64.8 Cu-AFX-con comparison sample 0

The above performance tests show that the high-silicon AFX zeolite molecular sieve synthesized by the small molecule organic template agent of the present invention has excellent hydrothermal stability.

The foregoing embodiments are only preferred embodiments of the present invention, and are not intended to limit the present invention in any form and in essence. It should be pointed out that those of ordinary skill in the art can also make Several improvements and supplements should also be considered as the protection scope of the present invention.

Claims (6)

1. A method for synthesizing a high-silicon AFX zeolite molecular sieve by using a small-molecule organic template is characterized by comprising the following steps of: firstly, a silicon-aluminum source, a sodium hydroxide solid and an organic template agent OSDA (OH) ₂ The aqueous solution and the water are SiO according to the molar ratio ₂ :Al ₂ O ₃ :Na ₂ O:OSDA(OH) ₂ :H ₂ Feeding according to the proportion of O = 25-72; wherein the organic template agent in the organic template agent aqueous solution is at least one of N, N ' -dimethyl-N, N, N ', N ' -tetraethyl-1, 6-hexamethylene diammonium hydroxide, N, N, N ', N ' -tetramethyl-N, N ' -diethyl-1, 6-hexamethylene diammonium hydroxide, N, N, N ', N ' -tetramethyl-N, N ' -diisopropyl-1, 6-hexamethylene diammonium hydroxide, N, N-dimethyl-N, N ', N ', N ' -tetraethyl-1, 6-hexamethylene diammonium hydroxide and N, N, N ' -trimethyl-N, N ', N ' -triethyl-1, 6-hexamethylene diammonium hydroxide.

2. The method for synthesizing a high-silicon AFX zeolite molecular sieve by using the small-molecule organic template as claimed in claim 1, wherein the preparation method of the organic template aqueous solution comprises the following steps: reacting trialkylamine R ₁ N(R ₂ ) ₂ Dissolving 1, 6-dibromohexane in acetonitrile according to a proportion, heating, refluxing and stirring for reaction; after the reaction is finished, carrying out suction filtration on a reaction product and washing the reaction product with acetonitrile; vacuum drying, and exchanging with hydroxide anion exchange resin to obtain organic template agent water solution with certain concentration; wherein, the trialkylamine R ₁ N(R ₂ ) ₂ Is at least one of N, N-diethylmethylamine, N-dimethylethylamine, N-dimethylisopropylamine and triethylamineAnd (4) seed preparation.

3. The method for synthesizing a high-silicon AFX zeolite molecular sieve by using a small-molecule organic template as claimed in claim 1, wherein the silicon-aluminum source is a combination of a silicon source and an aluminum source, and/or at least one of a USY molecular sieve, a ZSM-5 molecular sieve, a ZSM-22 molecular sieve, a ZSM-23 molecular sieve, a ZSM-11 molecular sieve, an MCM-22 molecular sieve and an FER molecular sieve, wherein the silicon source is selected from silica sol and/or tetraethyl silicate, and the aluminum source is selected from at least one of sodium metaaluminate, aluminum hydroxide, aluminum sulfate octadecahydrate and aluminum isopropoxide.

4. The method for synthesizing the high-silicon AFX zeolite molecular sieve by using the small-molecule organic template as claimed in claim 1, wherein the temperature of the crystallization reaction is 140-160 ℃ and the time is 1-5 days.

5. The high-silicon AFX zeolite molecular sieve prepared by the method for synthesizing the high-silicon AFX zeolite molecular sieve by using the small-molecule organic template as claimed in any one of claims 1 to 4.

6. A Cu-AFX catalyst, characterized in that the high-silicon AFX zeolite molecular sieve of claim 5 is sequentially subjected to calcination, ammonium ion exchange, cu ²⁺ Ion exchange and secondary roasting.

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