Method for solvent-free solid-phase synthesis of molecular sieve

Abstract

The invention discloses a solvent-free solid-phase synthesis method of a molecular sieve, which comprises the following steps: putting a solid-phase mixed raw material containing a molecular sieve raw material and a grinding material into a closed container, rotating and heating, and synthesizing to obtain the molecular sieve. The method is a novel technology for forming crystals through self-assembly of molecules in a solution under the assistance of mechanical force, the grinding material provides additional mechanical force for molecular sieve raw materials in the synthesis process, and no solvent is used or the use of the solvent is greatly reduced in the synthesis process. And the molecular sieve material with high quality, high crystallization degree and high specific surface area can be prepared in a relatively short time.

Description

Technical Field

[0001] The present application relates to a solvent-free solid phase molecular sieve synthesis method, belonging to the field of chemistry and chemical engineering. Background Art

[0002] Molecular sieve is an advanced porous material composed of inorganic materials with a regular pore structure. It can be used in separation, purification, adsorption and catalysis. The research on the artificial synthesis of zeolite molecular sieves can be traced back to the 1940s. In the early days, the artificial synthesis of zeolite molecular sieves was realized for the first time through the study of the phase transition of natural minerals in hot salt solutions, which opened the prelude to the artificial synthesis of zeolite molecular sieves. The earliest discovered was natural zeolite, of which there are about 50 kinds. Their uses were rarely developed in the early days. Their applications were mainly limited to gas drying, purification and separation. In the 1950s, the artificial synthesis of A and X zeolites, especially Y zeolite, and its application in catalytic cracking were regarded as the beginning of the industrialization and commercialization of zeolite materials. In the half century from then to now, the research on zeolite molecular sieves has gone through three major development stages, namely the synthesis of ZSM-5 in the 1970s, the synthesis of AIPO in the 1980s, and the development of zeolite molecular sieves in the 1980s. 4-n The synthesis of a series of molecular sieves and the synthesis of M4lS mesoporous molecular sieves in the 1990s. Today, there are at least more than 200 types of zeolite molecular sieves, with pore sizes expanding from micropores to mesopores, and skeleton chemical compositions expanding from aluminum silicate to aluminosilicates and aluminophosphates containing various heteroatoms. They have become indispensable catalytic and adsorption materials in petroleum processing and fine chemicals.

[0003] At present, the zeolite molecular sieve market is quite large. It is estimated that the size of the global zeolite molecular sieve market will exceed US$16 billion in 2020. Among them, the Asian market occupies most of the global market share, accounting for more than 60% of the global market volume. The United States is also one of the main consumers of the zeolite molecular sieve market. With the rapid development of the domestic economy, China's molecular sieve market has also shown a rapid growth trend. Therefore, the market prospects of molecular sieves in the future are very broad and have great development potential.

[0004] Traditional molecular sieve synthesis mainly uses a hydrothermal synthesis system, using an intermittent hydrothermal reaction synthesis kettle as a reaction vessel, which has low efficiency, large heat loss, and high energy consumption. At the same time, intermittent hydrothermal reaction synthesis kettles are usually synthesized using a stirring system, so there are many restrictions on the selection of synthesis formulas. The feed liquid needs to have good fluidity. If the feed liquid is a slurry with high viscosity or even a solid state, it is difficult to synthesize. Therefore, more solvents and organic templates are usually used, resulting in high synthesis costs and subsequent sewage treatment costs. At the same time, the synthesis speed of traditional molecular sieve hydrothermal synthesis kettles is slow and the synthesis efficiency is low. The particle size distribution of the products of traditional molecular sieve hydrothermal synthesis kettles is uneven, and there is a problem of large or small particle size. Therefore, the development of the molecular sieve synthesis industry is limited. At present, there is solid-phase molecular sieve synthesis work carried out on a laboratory scale, but the scale is small. At the same time, the biggest problem in the amplification of solid-phase synthesis is the influence of heat transfer and mass transfer in the reaction system. Summary of the invention

[0005] According to one aspect of the present application, in order to prepare high-quality, high-crystallization, and high-specific surface area molecular sieve materials in a relatively short period of time, a method for solvent-free solid phase synthesis of molecular sieves is provided, which is a novel technology that uses mechanical force to assist molecules to self-assemble in solution to form crystals. The traditional synthesis method is to use a large amount of solvent for synthesis under hydrothermal conditions, which consumes a lot of solvent and template agent, and the subsequent treatment and discharge of wastewater will greatly increase the cost of synthesis. The process of solvent-free solid phase synthesis does not require a large amount of solvent, and the reaction materials are solid. If traditional hydrothermal synthesis is used, the mechanical force-assisted synthesis method only takes a few hours to complete. Compared with the traditional synthesis method, the molecular sieve crystals prepared by the mechanical force-assisted synthesis method are more uniform, complete, and defect-free, and the crystals have a higher degree of crystallinity.

[0006] This application adopts the following technical solutions:

[0007] A method for solvent-free solid phase synthesis of molecular sieves comprises the following steps:

[0008] A solid phase mixed raw material containing a molecular sieve raw material and a grinding material is placed in a closed container, rotated and heated to synthesize a molecular sieve.

[0009] The grinding material provides additional mechanical force to the molecular sieve raw materials during the synthesis process.

[0010] During the molecular sieve solid phase synthesis process, no solvent is used or the use of solvent is greatly reduced.

[0011] The advantages of mechanical force-assisted synthesis of molecular sieves are that they can shorten preparation time, improve product quality and reduce chemical waste. The equipment cost is low and easy to operate. Mechanical force-assisted synthesis of molecular sieves has the advantages of short preparation time, high crystal quality, large specific surface area, reduced waste and wider applicability, and will become an important development direction of molecular sieve preparation technology in the future.

[0012] Optionally, the material of the grinding material is selected from at least one of agate, aluminum oxide, zirconium oxide, stainless steel, and synthetic resin.

[0013] Optionally, the grinding material has a shape selected from at least one of a sphere, a rod, a cube, a triangular pyramid, and a star.

[0014] Optionally, the closed container is a rotary reactor.

[0015] The molecular sieve synthesis device in the present application can collect the molecular sieve generated by the reaction through the discharge port at the bottom of the rotating reactor. The rotating reactor in the molecular sieve synthesis device is driven by a motor to rotate, and then it can be controlled to perform molecular sieve synthesis at a speed of 1 to 80 rpm.

[0016] Optionally, the rotation speed is 1 rpm to 80 rpm.

[0017] Optionally, the rotation speed is selected from any value among 1rpm, 5rpm, 10rpm, 20rpm, 30rpm, 40rpm, 50rpm, 60rpm, 70rpm, 75rpm, 80rpm, or a range value between any two points.

[0018] Optionally, the amount of the grinding material added is 5 to 80% of the volume of the inner cavity of the closed reaction container by volume.

[0019] Optionally, the heating temperature is 30-220°C.

[0020] Optionally, the heating temperature is selected from any value of 30°C, 40°C, 60°C, 90°C, 120°C, 150°C, 180°C, 200°C, 210°C, 220°C, or a range between any two points.

[0021] Optionally, the synthesis time is 0.5 to 168 hours.

[0022] Optionally, the synthesis time is selected from any value of 0.5h, 1h, 6h, 12h, 24h, 48h, 72h, 96h, 120h, 144h, 160h, 168h, or a range value between any two points.

[0023] Optionally, the molecular sieve raw material is selected from at least one of X-type molecular sieve raw material, Y-type zeolite molecular sieve raw material, A-type zeolite molecular sieve raw material, mordenite molecular sieve raw material, ZSM-5 type zeolite molecular sieve raw material, TS-1 type zeolite molecular sieve raw material, EAB type zeolite molecular sieve raw material, β-type zeolite molecular sieve raw material and clinoptilolite molecular sieve raw material.

[0024] Optionally, the synthesized molecular sieve is at least one of X-type molecular sieve, Y-type zeolite molecular sieve, A-type zeolite molecular sieve, mordenite molecular sieve, ZSM-5 type zeolite molecular sieve, TS-1 type zeolite molecular sieve, EAB type zeolite molecular sieve, β-type zeolite molecular sieve, and clinoptilolite molecular sieve.

[0025] Optionally, the preparation method comprises the following steps:

[0026] A solid phase mixed raw material containing a molecular sieve raw material and a grinding material is placed in a closed container, rotated and heated to synthesize a molecular sieve.

[0027] The method can shorten the preparation time, improve product quality and reduce chemical waste, etc., and can effectively reduce the amount of template and solvent used in the traditional hydrothermal synthesis process, and is particularly suitable for the synthesis process in which the system is a solid phase. The method can heat the molecular sieve synthesis rotary reactor, and then the molecular sieve synthesis can be performed at different temperatures.

[0028] The beneficial effects of this application include:

[0029] 1) The method for solvent-free solid phase synthesis of molecular sieves of the present application is to synthesize molecular sieves under solvent-free solid phase conditions by mechanical force assistance. This method can prepare molecular sieve materials in a relatively short time. The method and equipment are simple and highly automated, and are particularly suitable for the synthesis process in which the molecular sieve synthesis system is a solid phase, with low equipment cost and easy operation;

[0030] 2) The method for solvent-free solid phase synthesis of molecular sieves in the present invention can be synthesized using a solid phase synthesis system. The advantage of solid phase synthesis is that the autogenous pressure of the reaction system is low, the pressure resistance requirement of the equipment is low, and the equipment cost is greatly reduced. At the same time, the solid phase system can reduce the template agent. No solvent is required, the discharge of chemical wastewater and waste is effectively reduced, environmental pollution is reduced, and the requirements of atomic economy and green chemistry are met, which is more suitable for the development of modern chemical industry. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 This is a scanning electron microscope image of the product synthesized in Example 1 of this application.

[0032] Figure 2 This is the X-ray powder diffraction image of the product synthesized in Example 1 of the present application.

[0033] Figure 3 This is a scanning electron microscope image of the product synthesized in Example 2 of this application.

[0034] Figure 4 This is the X-ray powder diffraction image of the product synthesized in Example 2 of this application. DETAILED DESCRIPTION

[0035] The present application is described in detail below with reference to embodiments, but the present application is not limited to these embodiments.

[0036] Unless otherwise specified, the raw materials in the examples of this application were purchased through commercial channels.

[0037] The analysis method in the examples of this application is as follows:

[0038] In the examples of the present application, the SEM morphology analysis of the product was performed using a Hitachi SU8020 scanning electron microscope.

[0039] In the examples of the present application, the X-ray powder diffraction phase analysis (XRD) of the product was performed using an X'Pert PRO X-ray diffractometer from PANalytical of the Netherlands, with a Cu target, a Kα radiation source (λ=0.15418 nm), a voltage of 40 KV, and a current of 40 mA.

[0040] According to one embodiment of the present application, the method of mechanical synthesis of molecular sieves is characterized in that the method comprises the following steps:

[0041] The raw materials of the molecular sieve to be synthesized are added to the rotating reactor, and the grinding material is added to the reactor. The material of the grinding material includes one or more mixtures of materials such as agate, aluminum oxide, zirconium oxide, stainless steel or synthetic resin. The shape of the grinding material includes one or more mixtures of different shapes such as sphere, rod, cube, triangular pyramid or star. After sealing, the temperature is increased and rotated. The speed during the reaction is between 1rpm and 80rpm, the temperature of the rotating reactor is between 30℃ and 220℃, and the molecular sieve synthesis time is between 0.5 hours and 168 hours. The grinding material continuously applies mechanical force to the synthetic raw materials during the rotation process, and the molecular sieve product is poured out through the discharge port after the reaction is completed.

[0042] Specifically, the molecular sieve that can be synthesized in the step is at least one of: X-type molecular sieve, Y-type zeolite molecular sieve, A-type zeolite molecular sieve, mordenite molecular sieve, ZSM-5 type zeolite molecular sieve, TS-1 type zeolite molecular sieve, EAB type zeolite molecular sieve, β-type zeolite molecular sieve, and clinoptilolite molecular sieve.

[0043] Example 1

[0044] 60g of ethyl orthosilicate, 5g of tetrabutyl titanate, and 15g of tetrapropylammonium hydroxide were placed in a molecular sieve synthesis container; agate grinding beads were added to the reaction system, and the reaction time was 24 hours at a temperature of 170°C and a rotation speed of 40rpm to synthesize the titanium silicon molecular sieve TS-1 product. The scanning electron microscope image of the synthesized product is shown in FIG. Figure 1 As shown, the X-ray powder diffraction image of the synthesized product is as follows Figure 2 shown.

[0045] Example 2

[0046] 35g of aluminum hydroxide, 30g of sodium silicate, and 15g of sodium hydroxide were placed in a molecular sieve synthesis container, and zirconium oxide and aluminum oxide grinding rods were added to the reaction system. The reaction time was 6 hours at a temperature of 100°C and the rotation speed was 70rpm to synthesize an X-type molecular sieve product. The scanning electron microscope image of the synthesized product is shown in FIG. Figure 3 As shown, the X-ray powder diffraction image of the synthesized product is as follows Figure 4 shown.

[0047] Example 3

[0048] 75g of pseudo-boehmite, 60g of fumed silica and 25g of n-octylamine were placed in a molecular sieve synthesis container; stainless steel ground triangular pyramids were added to the reaction system, and the reaction time was 72 hours at a temperature of 200°C and a rotation speed of 20rpm to synthesize a type A molecular sieve product.

[0049] Embodiments 4 to 13

[0050] The specific ingredient types, materials and synthesis conditions are shown in Table 1 below. The synthesis equipment and other operations during the synthesis process are the same as those in Example 1.

[0051] Table 1 Molecular sieve synthesis conditions of Examples 4-13

[0052]

[0053] The above are only a few embodiments of the present application and do not constitute any form of limitation to the present application. Although the present application is disclosed as above with preferred embodiments, it is not intended to limit the present application. Any technician familiar with the profession, without departing from the scope of the technical solution of the present application, using the technical content disclosed above to make slight changes or modifications are equivalent to equivalent implementation cases and fall within the scope of the technical solution.

Claims

1. A method for solvent-free solid phase synthesis of molecular sieves, characterized in that: The steps include: A solid phase mixed raw material containing a molecular sieve raw material and a grinding material is placed in a closed container, rotated and heated to synthesize a molecular sieve.

2. The preparation method according to claim 1, characterized in that: The material of the grinding material is selected from at least one of agate, aluminum oxide, zirconium oxide, stainless steel and synthetic resin.

3. The preparation method according to claim 1, characterized in that: The shape of the grinding material is selected from at least one of sphere, rod, cube, triangular pyramid and star.

4. The preparation method according to claim 1, characterized in that: The rotation speed is 1 rpm to 80 rpm.

5. The preparation method according to claim 1, characterized in that: The heating temperature is 30-220°C.

6. The preparation method according to claim 1, characterized in that: The synthesis time is 0.5 to 168 hours.

7. The preparation method according to claim 1, characterized in that: The molecular sieve raw material is selected from at least one of X-type molecular sieve raw material, Y-type zeolite molecular sieve raw material, A-type zeolite molecular sieve raw material, mordenite molecular sieve raw material, ZSM-5 type zeolite molecular sieve raw material, TS-1 type zeolite molecular sieve raw material, EAB type zeolite molecular sieve raw material, β-type zeolite molecular sieve raw material and clinoptilolite molecular sieve raw material.

8. The preparation method according to claim 1, characterized in that: The closed container is a rotary reactor.

9. The preparation method according to claim 1, characterized in that: The steps of the preparation method are: A solid phase mixed raw material containing a molecular sieve raw material and a grinding material is placed in a closed container, rotated and heated to synthesize a molecular sieve.

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