CN102963907A - Pentasil type zeolite molecular sieve synthetic method - Google Patents

Abstract

The invention belongs to the field of molecular sieve catalytic materials, and discloses a method for synthesizing pentasil-type zeolite molecular sieves. Aluminum source compounds, alkali source compounds, silicon source compounds, additives, organic templates and water are mixed and stirred evenly to form a reaction mixture; hydrothermal crystallization, filtration, washing and drying to obtain the pentasil type zeolite molecular sieve. Wherein, the additive is a polyether compound. The method of the invention has the advantages of fast crystallization speed, low cost, small amount of template agent, etc., and the synthesized pentasil type zeolite molecular sieve has high crystallinity and purity.

Description

A kind of synthetic method of pentasil type zeolite molecular sieve

technical field

The invention belongs to the field of molecular sieve catalytic materials, and in particular relates to a method for synthesizing a pentasil type zeolite molecular sieve. Polyether compounds are used as additives to synthesize the molecular sieve.

Background technique

Because zeolite molecular sieves have good thermal stability, hydrothermal stability; controllable acidity; Structure and Synthesis of Zeolite Molecular Sieves; Jilin University Press, 1987.; Xu Ruren, Pang Wenqin, Yu Jihong, Huo Qisheng, Chen Jiesheng Molecular Sieves and Porous Materials Chemistry, 2004.; Zeolite Molecular Sieves by Dalian Institute of Physics and Chemistry, Chinese Academy of Sciences, Science Press, 1978. .). In addition to silicon source, aluminum source, titanium source, alkali source and water in the synthesis of molecular sieve, template agent is also indispensable. In the prior art, expensive templates are often used to regulate the crystal morphology of molecular sieves, to adjust the ratio of silicon to aluminum or silicon to titanium and other characteristics of molecular sieves, which greatly increases the synthesis cost and difficulty of adjustability of molecular sieves. At the same time, most of the templates are nitrogen-containing or long carbon chain organic compounds, which increases the synthesis cost of molecular sieves to a certain extent, and nitrogen oxides are produced when the templates are removed by roasting, causing pollution to the environment.

The general formula of polyethylene glycol is H(OCH ₂ CH ₂ ) _n OH, PEG for short. Because polyethylene glycol (PEG) has different molecular polymerization degrees, its molecular weight can be controlled, thereby regulating the state of polyethylene glycol molecular chains in different solution environments: in anhydrous state, it is a zigzag long chain molecule, but in solution After water, it forms a zigzag shape. Therefore, the mechanism and results of various material synthesis can be changed by using the different states of molecular chains and the interaction between host and guest molecules in solution.

The current research on the influence of polyethylene glycol (PEG) in the synthesis of porous materials mainly includes the following aspects: (1) The crown ether-like properties of polyethylene glycol. The structure of PEG contains ether oxygen bonds, which has the properties of crown ethers and can complex with metal ions. Jiao et al. added PEG to silicon-containing titanium precursor solution to prepare TiO ₂ /SiO ₂ materials with porous structure (Jiao, J.; Xu, Q.; Li, L.; Tsubasa, T.; Kobayashi, T. Colloid & Polymer Science 2008, 286, 1485.; Jiao, J.; Xu, Q.; Li, L. Journal of Colloid and Interface Science 2007, 316, 596.). (2) The reducibility of polyethylene glycol. The polymer interacts with the metal to form micelles to act as a stabilizer for metal ions, preventing the accumulation and precipitation of metal ions. PEG molecules can interact with metal ions to form crown-like holes and act as reducing agents (Krishnan, CV; Chen, J.; Burger, C.; Chu, B. The Journal of Physical Chemistry B 2006, 110, 20182.; Chen , D.-H.; Huang, Y.-W. Journal of Colloid and Interface Science 2002, 255, 299.). (3) Control of the silicon-aluminum ratio of the molecular sieve structure. Delprato's group directly synthesized molecular sieves with FAU structure with Si/Al greater than 3 by adding organic template crown ether molecules without post-treatment dealumination and other processes. Similarly, the addition of _{-OCH2CH2 -} organic species during the synthesis of Y-type zeolites favors the synthesis of high _SiO2 / _{Al2O3 zeolites} (Delprato, F.; Delmotte, L.; Guth, JL; Huve, L. Zeolites, 10, 546.; Dougnier, F.; Patarin, J.; Guth, JL; Anglerot, D. Zeolites 1992, 12, 160.). (4) Shape control and tailoring. The crystal morphology is determined by the growth rate of crystal planes. Different crystal planes have different surface energies. Therefore, the addition of organic or inorganic substances can change the relative surface energy of different crystal planes and change the crystal morphology. Polyethylene glycol PEG can be used as a co-solvent to control the morphology of transition metal substituted AIPO ₄ -5 (AFI) molecular sieves. The addition of polyethylene glycol significantly inhibited the growth of Me-AFI crystals in the c-axis direction; and with the increase of PEG/H ₂ O ratio, the aspect ratio of Cr-AFI crystals decreased (Tian, D.; Yan, W. ; Cao, X.; Yu, J.; Xu, R. Chemistry of Materials 2008, 20, 2160.). At the same time, polyethylene glycol was used as crystal growth inhibitors (crystal growth inhibitors, CGIs) to control the morphology of the synthesized SAPO-34 crystals. The crystal inhibitors firstly interacted with Al-P species, shortened the nucleation time, and increased the nucleation number ( Venna, SR; Carreon, MA The Journal of Physical Chemistry B 2008, 112, 16261.). (5) Effect of polyethylene glycol on crystal particle size. It is precisely because of the characteristics of more exposed acidic sites, high specific surface area and short diffusion path that nano zeolites have attracted widespread attention. Wang et al. added polyethylene glycol and CTAB to the system of synthesizing IM-5 nano zeolite, trying to adjust the particle size of molecular sieve by adding surfactant (Wang, L.; Yang, W.; Xin, C.; Ling , F.; Sun, W.; Fang, X.; Yang, R. Materials Letters 2012, 69, 16.). (6) The application of polyethylene glycol in the synthesis of multi-level composite channels. Tanaka et al. sol-gel method combined with phase separation process to prepare hierarchical composite porous structure materials (Tanaka, N.; Kobayashi, H.; Ishizuka, N.; Minakuchi, H.; Nakanishi, K.; Hosoya, K.; Ikegami, T. Journal of Chromatography A 2002, 965, 35.; Ishizuka, N.; Minakuchi, H.; Nakanishi, K.; Soga, N.; Tanaka, N. Journal of Chromatography A 1998, 797, 133.; Ishizuka, N.; Minakuchi, H.; Nakanishi, K.; Hirao, K.; Tanaka, N. Colloids and Surfaces A: Physicochemical and Engineering Aspects 2001, 187-188, 273.). PEG is added to the TMOS solution, and a cross-linked macroporous silicon material is obtained by hydrolysis and condensation. Since PEG affects the phase separation of silicon species from sol to gel, the amount of macroporous can be controlled by adjusting the amount of PEG. Diameter; while the mesopore size is mainly obtained by post-treatment of ammonia solution.

In addition, the relative hydrophilicity and lipophilicity of polyether compounds can be adjusted by substituting groups, and they have the characteristics of low price, easy synthesis, and low toxicity. The use of polyether compounds in the synthesis and preparation of pentasil-type zeolite molecular sieves has not been proposed in the prior art.

Contents of the invention

The invention provides a molecular sieve containing alkali metal ions in a framework structure and a synthesis method thereof. The present invention adopts polyethylene glycol and polypropylene glycol-type polyether compounds that do not contain nitrogen elements to synthesize the pentasil-type zeolite molecular sieve, which can accelerate the crystallization of the molecular sieve and reduce the dosage of the template agent; Synthesize pure silica molecular sieves or silica-alumina molecular sieves with relatively high crystallinity.

The present invention aims to provide an innovative method for synthesizing pure silicon molecular sieves or zeolite molecular sieves with a silicon-aluminum structure by using polyether compound additives, mixing aluminum source compounds, alkali source compounds, silicon source compounds, additives, organic templates and water, stirring evenly to form a reaction mixture; performing hydrothermal crystallization on the reaction mixture, filtering, washing and drying to obtain the pentasil type zeolite molecular sieve; wherein the additive is a polyether compound.

The aluminum source includes sodium metaaluminate, aluminum sulfate, aluminum nitrate and aluminum isopropoxide. The alkali source includes potassium hydroxide and sodium hydroxide. The silicon source includes silica sol, silica gel, water glass and white carbon black. The polyether compounds include polyethylene glycol [HO(CH ₂ CH ₂ O) _n H, PEO], polypropylene glycol [HO(CH(CH ₃ )CH ₂ O) _n H, PPO] and EO and PO A polymer of structural units. Wherein, the structural formula of the polymer containing EO and PO structural units is EO _m PO _n EO _t , wherein m, n, t can be from 0 to ∞.

In the present invention, the mass ratio of SiO ₂ : polyether compound in the whole synthesis system of the polyether compound is 1: (5-100%).

In the present invention, silica-alumina molecular sieves or guiding glue can also be added as seed crystals in the reaction mixture, and the mass ratio of SiO ₂ : SiO2 in seed crystals in the whole synthesis system is 1: (0-10%).

In the present invention, the molar equivalent of _Al2O3 in the aluminum source compound: the molar equivalent of _SiO2 : alkali source compound: _organic template agent: the molar ratio of water is (0-0.05): 1: (0.05-0.5) :(0-0.5):(5-100).

In the present invention, the temperature of the hydrothermal crystallization is 100-200° C., and the time is 5-48 hours.

Specifically, the order of adding and mixing aluminum source, alkali source, silicon source, polyether compound and water in the present invention is not limited.

In the present invention, the aluminum source may or may not be added. In the reaction mixture, silica-alumina molecular sieves or guiding glue can be optionally added as crystal seeds.

In the present invention, the formula of the guiding glue used as the seed crystal is SiO ₂ : 0.10-0.35TPAOH: 6-35H ₂ O: 4EtOH, which is used directly after crystallization at 80-185°C for 2-72h. The molecular sieve used as the seed crystal may have the same or different structure as the target synthesized molecular sieve.

According to the method of the invention, a pentasil type zeolite molecular sieve can be prepared, which is a molecular sieve with an MFI or MEL structure. In the present invention, polyether compounds are used as additives to synthesize molecular sieves with pure silicon and silicon-aluminum structures, and the synthesis cost is reduced by adding polyether compounds, while reducing environmental pollution by nitrogen-containing organic compounds. In the present invention, the strong complexation effect of polyether compounds on alkali metal ions is used to promote the crystallization of molecular sieves and shorten the crystallization time; at the same time, the dosage of organic templates is reduced by adding polyethylene glycol. In the present invention, the cost of the synthesis process is reduced by reducing the dosage of the organic template agent and shortening the crystallization time.

The method of the invention has the advantages of fast crystallization speed, low cost, small amount of template agent, etc., and the synthesized pentasil type zeolite molecular sieve has high crystallinity and purity.

Description of drawings

Fig. 1 shows the XRD comparison chart of the pure silicon ZSM-5 molecular sieve synthesized by using polyethylene glycol as an additive in the present invention.

Fig. 2 shows the crystallization curve of the pure silicon ZSM-5 molecular sieve synthesized with polyethylene glycol as an addition in the present invention.

Figure 3 shows the topography of pure silicon ZSM-5 molecular sieve synthesized with polyethylene glycol as an addition in the present invention.

Fig. 4 shows the XRD comparison diagram of ZSM-5 molecular sieve synthesized by using polyethylene glycol as an additive in the present invention (SiO ₂ /Al ₂ O ₃ is 30).

Fig. 5 shows the crystallization curve of ZSM-5 molecular sieve synthesized by using polyethylene glycol as an additive in the present invention (SiO ₂ /Al ₂ O ₃ is 30).

Detailed ways

The present invention will be further described in detail in conjunction with the following specific embodiments and accompanying drawings. The process, conditions, reagents, experimental methods, etc. for implementing the present invention are general knowledge and common knowledge in the art except for the content specifically mentioned below, and the present invention has no special limitation content.

The synthesis method of the pentasil type zeolite molecular sieve of the present invention is to mix the aluminum source compound, the alkali source compound, the silicon source compound, the additive, the organic template agent and water, and stir evenly to form a reaction mixture; the reaction mixture is hydrothermally crystallized, and the filtering, washing and drying to obtain pentasil type zeolite molecular sieve; wherein, the additive is a polyether compound.

(1) Mix aluminum source compound, alkali source compound, silicon source compound, additive, organic template, water and polyether compound, and stir evenly to form a reaction mixture. The order of addition is not limited.

(2) Transfer the obtained reaction mixture to a high-pressure reactor for hydrothermal crystallization, control the crystallization temperature and time at 100-200°C and 0-48 hours, respectively, and filter the crystallized reaction mixture with deionized water Washing, drying, etc. to obtain a zeolite molecular sieve with a silicon-aluminum structure.

Wherein, the aluminum source includes sodium metaaluminate, aluminum sulfate, aluminum nitrate, and aluminum isopropoxide. Alkali sources include potassium hydroxide and sodium hydroxide.

Silicon sources include silica sol, silica gel, water glass, and white carbon black. Polyether compounds include polyethylene glycol [HO(CH ₂ CH ₂ O) _n H, PEO], polypropylene glycol [HO(CH(CH ₃ )CH ₂ O) _n H, PPO] and structural units containing EO and PO of polymers. Wherein, the structural formula of the polymer containing EO and PO structural units is EO _m PO _n EO _t , wherein m, n, t can be from 0 to ∞.

In the present invention, the mass ratio of SiO ₂ : polyether compound in the whole synthesis system of the polyether compound is 1: (5-100%).

In the present invention, silica-alumina molecular sieves or guiding glue can also be added as seed crystals in the reaction mixture, and the mass ratio of SiO ₂ : seed crystals in the whole synthesis system is 1: (0-10%).

In the present invention, the molar equivalent of _Al2O3 in the aluminum source compound: the molar equivalent of _SiO2 : alkali source compound: organic template agent: _the molar ratio of water is (0-0.05): 1: (0.05-0.5): ( 0-0.5): (5-100).

In the present invention, the temperature of hydrothermal crystallization is 100-200° C., and the time is 5-48 hours.

In the present invention, the formula of the guiding glue used as the seed crystal is SiO ₂ : 0.10-0.35TPAOH: 6-35H ₂ O: 4EtOH, which is used directly after crystallization at 80-185°C for 2-72h. The molecular sieve used as the seed crystal may have the same or different structure as the target synthesized molecular sieve. The "guiding gel" in the present invention is a silicon or silicon-aluminum-containing sol or molecular sieve slurry obtained by crystallization at 50-150°C and having a structure-guiding effect.

Example 1

A kind of preparation method of pure silicon Silicalite-1 molecular sieve, its concrete steps are as follows:

(1) Dissolve solid NaOH with deionized water, stir and clarify, then add polyethylene glycol (PEG400) to form a clear solution; add solid silica gel to the above solution, stir for 30-60 minutes, finally add TPA ⁺ guide gel, stir uniform. In the above reaction mixture, the molar ratio of the molar equivalent of Al ₂ O ₃ in the aluminum source compound: the molar equivalent of _{SiO 2} : the alkali source compound: _{H 2} O is 0:1:0.055:12. The mass ratio of SiO ₂ : guiding glue: PEG400 is 1:5%:20%.

(2) Transfer the obtained reaction mixture to a high-pressure reactor for hydrothermal crystallization, and crystallize at 175°C for 12 hours. The crystallized product is filtered, washed with deionized water, dried, etc. to obtain pure silicon containing MFI structure Zeolite molecular sieve.

Comparative example 1

A kind of preparation method of pure silicon Silicalite-1 molecular sieve, its concrete steps are as follows:

(1) Dissolve solid NaOH with deionized water, stir to clarify the solution; add solid silica gel to the above solution, stir for 30-60 minutes, and finally add TPA ⁺ guide gel, stir evenly. In the above reaction mixture, the molar ratio of the molar equivalent of Al ₂ O ₃ in the aluminum source compound: the molar equivalent of _{SiO 2} : the alkali source compound: _{H 2} O is 0:1:0.055:12. The mass ratio of SiO ₂ :guiding glue is 1:5%.

(2) Transfer the obtained reaction mixture to a high-pressure reactor for hydrothermal crystallization, and crystallize at 175°C for 12 hours. The crystallized product is filtered, washed with deionized water, dried, etc. to obtain pure silicon containing MFI structure Zeolite molecular sieve.

According to the experimental results, it can be seen that the crystallinity of the molecular sieve sample prepared without adding PEG was 85% in 12 hours, and after adding PEG according to the method of this example, after the same crystallization time, the crystallinity of pure silicon Silicalite-1 molecular sieve reached 100%. . It can be seen from Figure 1 that Silicalite-1 with PEG added has a pure-phase MFI structure without any impurity phases. As shown in Figure 2, comparing the crystallization curves of the two samples shows that the addition of PEG can significantly promote the crystallization of Silicalite-1. The morphology of the above samples is shown in Figure 3. Both samples are coffin-shaped crystals with a size of 100-200nm, but the molecular sieve samples prepared without PEG have more smaller crystal grains or amorphous substances; the addition of PEG promotes crystallization , the grain dispersion is more uniform.

Example 2

A kind of preparation method of silicon-aluminum ZSM-11 molecular sieve, its specific steps are as follows:

(1) Dissolve solid NaOH with deionized water, stir and clarify, then add polyethylene glycol (PEG400) to form a clear solution; add solid silica gel to the above solution, stir for 30-60 minutes, and finally add tetrabutylammonium hydroxide (TBAOH) , stir well. In the above reaction mixture, the molar ratio of the molar equivalent of Al ₂ O ₃ in the aluminum source compound: the molar equivalent of SiO ₂ : the alkali source compound: TBAOH: _{H 2} O is 0:1:0.055:0.2:12. Wherein the mass ratio of SiO ₂ :PEG400 is 1:20%.

(2) Transfer the obtained reaction mixture to a high-pressure reactor for hydrothermal crystallization, and crystallize at 175°C for 24 hours. The crystallized product is filtered, washed with deionized water, dried, etc. to obtain pure silicon with MEL structure Zeolite molecular sieve.

Comparative example 2

A kind of preparation method of silicon-aluminum ZSM-11 molecular sieve, its specific steps are as follows:

(1) Dissolve solid NaOH with deionized water, stir to clarify the solution; add solid silica gel to the above solution, stir for 30-60 minutes, finally add TBAOH, and stir evenly. In the above reaction mixture, the molar ratio of the molar equivalent of Al ₂ O ₃ in the aluminum source compound: the molar equivalent of SiO ₂ : the alkali source compound: TBAOH: _{H 2} O is 0:1:0.055:0.2:12.

(2) Transfer the obtained reaction mixture to a high-pressure reactor for hydrothermal crystallization, and crystallize at 175°C for 24 hours. The crystallized product is filtered, washed with deionized water, dried, etc. to obtain pure silicon with MEL structure Zeolite molecular sieve.

Example 3

A kind of preparation method of pure silicon Silicalite-1 molecular sieve, its concrete steps are as follows:

(1) Dilute concentrated sulfuric acid to form dilute sulfuric acid solution A; at the same time, dissolve sodium silicate nonahydrate (Na ₂ SiO ₃ ·9H ₂ O) with hot water to form clear solution B. Under mechanical stirring, add the clear solution A dropwise to the solution B. After the acid is completely added dropwise, filter the above turbid solution to obtain an amorphous filter cake, and feed the filter cake according to the following formula. Aluminum source compound The molar equivalent of Al ₂ O ₃ : the molar equivalent of SiO ₂ : the molar ratio of alkali source compound: _{H 2} O is 0:1:0.055:35, and finally add TPA ⁺ guide glue, stir for 30-60 minutes until uniform Can. The mass ratio of SiO ₂ : guiding glue: PEG400 is 1:5%:20%.

(2) Transfer the obtained reaction mixture to a high-pressure reactor for hydrothermal crystallization, and crystallize at 175°C for 12 hours. The crystallized product is filtered, washed with deionized water, dried, etc. to obtain pure silicon containing MFI structure Zeolite molecular sieve.

Comparative example 3

A kind of preparation method of pure silicon Silicalite-1 molecular sieve, its concrete steps are as follows:

(1) Dilute concentrated sulfuric acid to form dilute sulfuric acid solution A; at the same time, dissolve sodium silicate nonahydrate (Na ₂ SiO ₃ ·9H ₂ O) with hot water to form clear solution B. Under mechanical stirring, add the clear solution A dropwise to the solution B. After the acid is completely added dropwise, filter the above turbid solution to obtain an amorphous filter cake, and feed the filter cake according to the following formula. Aluminum source compound The molar equivalent of Al ₂ O ₃ : the molar equivalent of SiO ₂ : the molar ratio of alkali source compound: _{H 2} O is 0:1:0.055:35, and finally add TPA ⁺ guide glue, stir for 30-60 minutes until uniform Can. The mass ratio of SiO ₂ :guiding glue is 1:5%.

(2) Transfer the obtained reaction mixture to a high-pressure reactor for hydrothermal crystallization, and crystallize at 175°C for 24 hours. The crystallized product is filtered, washed with deionized water, dried, etc. to obtain pure silicon containing MFI structure Zeolite molecular sieve.

Through the comparison of Example 3 and Comparative Example 4, in the same synthesis system, and the crystallinity of the produced crystal is about 99%, adding quantitative PEG can directly shorten the crystallization time from 24 hours to 12 hours. Reduce production cost consumption to a great extent.

Example 4

A kind of preparation method of ZSM-5 molecular sieve, its concrete steps are as follows:

(1) Dissolve solid NaOH and sodium metaaluminate in deionized water, stir and clarify, then add polyethylene glycol (PEG400) to form a clear solution; add solid silica gel to the above solution, stir for 30-60 minutes, and finally add TPA ⁺ guide glue, stir well. The molar equivalent of Al ₂ O ₃ in the above-mentioned aluminum source compound: the molar equivalent of SiO ₂ : the alkali source compound: the guiding gel: PEG400: _{H 2} O The molar ratio is 0.033:1:0.055:12; wherein SiO ₂ :guiding gel The mass ratio of :PEG400 is 1:5%:20%.

(2) Transfer the obtained reaction mixture to a high-pressure reactor for hydrothermal crystallization, and crystallize at 175°C for 12 hours. The crystallized product is filtered, washed with deionized water, dried, etc. to obtain silicon aluminum with MFI structure Zeolite molecular sieve.

Comparative example 4

A kind of preparation method of ZSM-5 molecular sieve, its concrete steps are as follows:

(1) Dissolve solid NaOH and sodium metaaluminate in deionized water to form a clear solution; add solid silica gel to the above solution, stir for 30-60 minutes, and finally add guide gel containing TPA ⁺ , stir evenly. The molar equivalent of Al ₂ O ₃ in the above-mentioned aluminum source compound: the molar equivalent of SiO ₂ : the alkali source compound: _{H 2} O is 0.033:1:0.055:12; wherein the mass ratio of SiO ₂ :guiding glue is 1 : 5%.

(2) Transfer the obtained reaction mixture to a high-pressure reactor for hydrothermal crystallization, and crystallize at 175°C for 12 hours. The crystallized product is filtered, washed with deionized water, dried, etc. to obtain silicon aluminum with MFI structure Zeolite molecular sieve.

Compared with the pure silicon system, the induction period of the silica-alumina molecular sieve is significantly increased, and the addition of PEG further significantly promotes the nucleation and crystallization of the molecular sieve. According to the experimental results, the crystallinity of the ZSM-5 molecular sieve sample crystal prepared without adding PEG was 89% in 12 hours, and after adding PEG according to the method of this embodiment, after the same rod crystallization time, the crystallinity of ZSM-5 molecular sieve up to 100%. It can be seen from Figure 4 that ZSM-5 added with PEG has a pure-phase MFI structure without any impurity phase. As shown in Figure 5, comparing the crystallization curves of the two crystals, it can be seen that the addition of PEG can significantly promote the crystallization of ZSM-5.

Example 5

A kind of preparation method of ZSM-5 molecular sieve, its concrete steps are as follows:

(1) Dissolve aluminum sulfate in dilute sulfuric acid aqueous solution and stir to form a clear solution A; at the same time, dissolve sodium silicate nonahydrate (Na ₂ SiO ₃ ·9H ₂ O) with hot water to form a clear solution B. Under mechanical stirring, add the clear solution A dropwise to the solution B. After the acid is completely added dropwise, filter the above turbid solution to obtain a filter cake, and feed the silica-alumina amorphous filter cake. The molar equivalent of Al ₂ O ₃ in the above-mentioned aluminum source compound: the molar equivalent of SiO ₂ : the molar ratio of alkali source compound: TPAOH: _{H 2} O is 0.033: 1: 0.055: 0.1: 35, wherein the mass of SiO ₂ : PEG400 The ratio is 1:20%.

(2) Transfer the obtained reaction mixture to a high-pressure reactor for hydrothermal crystallization, and crystallize at 175°C for 24 hours. The crystallized product is filtered, washed with deionized water, dried, etc. to obtain silicon aluminum with MFI structure Zeolite molecular sieve.

Comparative example 5

A kind of preparation method of ZSM-5 molecular sieve, its concrete steps are as follows:

(1) Dissolve aluminum sulfate in dilute sulfuric acid aqueous solution and stir to form a clear solution A; at the same time, dissolve sodium silicate nonahydrate (Na ₂ SiO ₃ ·9H ₂ O) with hot water to form a clear solution B. Under mechanical stirring, add the clear solution A dropwise to the solution B. After the acid is completely added dropwise, filter the above turbid solution to obtain a filter cake, and feed the silica-alumina amorphous filter cake. The molar ratio of the molar equivalent of Al ₂ O ₃ : the molar equivalent of SiO ₂ : the alkali source compound: TPAOH: _{H 2} O in the above-mentioned aluminum source compound is 0.033:1:0.055:0.35:35.

(2) Transfer the obtained reaction mixture to a high-pressure reactor for hydrothermal crystallization, and crystallize at 175°C for 24 hours. The crystallized product is filtered, washed with deionized water, dried, etc. to obtain silicon aluminum with MFI structure Zeolite molecular sieve.

Example 5 and Comparative Example 5 used the same silicon-aluminum source to prepare silica-alumina zeolite molecular sieves containing MFI structure. It can be found by comparison that, in the case of adding quantitative polyethylene glycol PEG400, the crystallinity of both can be guaranteed to be 98%, embodiment 5 can reduce the amount of organic templating agent TPAOH from 0.35 to 0.1.

Example 6

A kind of preparation method of ZSM-5 molecular sieve, its concrete steps are as follows:

(1) Dissolve solid NaOH and sodium metaaluminate (NaAlO ₂ ) with deionized water, stir and clarify, then add polyethylene glycol (PEG400) to form a clear A solution; add solid silica gel to the above solution, and stir for 30-60 minutes , continue to add TPA ⁺ guide glue, stir evenly. The molar equivalent of Al ₂ O ₃ in the above-mentioned aluminum source compound: the molar equivalent of SiO ₂ : the molar ratio of alkali source compound: TPAOH: _{H 2} O is 0.033: 1: 0.055: 0.1: 12, wherein the mass of SiO ₂ : PEG400 The ratio is 1:100%.

(2) Transfer the obtained reaction mixture to a high-pressure reactor for hydrothermal crystallization, and crystallize at 175°C for 12 hours. The crystallized product is filtered, washed with deionized water, dried, etc. to obtain silicon aluminum with MFI structure Zeolite molecular sieve.

Example 6

A kind of preparation method of ZSM-5 molecular sieve, its concrete steps are as follows:

(1) Dissolve solid NaOH and sodium metaaluminate (NaAlO ₂ ) with deionized water, stir and clarify, then add polyethylene glycol (PEG6000) to form a clear A solution; add solid silica gel to the above solution, and stir for 30-60 minutes , continue to add TPA ⁺ guide glue, stir evenly. The molar equivalent of Al ₂ O ₃ in the above-mentioned aluminum source compound: the molar equivalent of SiO ₂ : the molar ratio of alkali source compound: ethylenediamine: water is 0.033: 1: 0.055: 0.28: 12, wherein the mass of SiO ₂ : PEG6000 The ratio is 1:50%.

(2) Transfer the obtained reaction mixture to a high-pressure reactor for hydrothermal crystallization, and crystallize at 175°C for 12 hours. The crystallized product is filtered, washed with deionized water, dried, etc. to obtain silicon aluminum with MFI structure Zeolite molecular sieve.

Example 7

A kind of preparation method of ZSM-5 molecular sieve, its concrete steps are as follows:

(1) Dissolve solid NaOH and sodium metaaluminate (NaAlO ₂ ) with deionized water, stir and clarify, then add polyethylene glycol (PEG20000) to form a clear A solution; add solid silica gel to the above solution, and stir for 30-60 minutes , continue to add TPA ⁺ guide glue, stir evenly. The molar equivalent of Al ₂ O ₃ in the above-mentioned aluminum source compound: the molar equivalent of SiO ₂ : the alkali source compound: ethylenediamine: the molar ratio of _{H 2} O is 0.033:1:0.055:0.28:12, wherein SiO ₂ : PEG20000 The mass ratio is 1:20%.

(2) Transfer the obtained reaction mixture to a high-pressure reactor for hydrothermal crystallization, and crystallize at 140°C for 24 hours. The crystallized product is filtered, washed with deionized water, dried, etc. to obtain a silicon-alumina containing MFI structure Zeolite molecular sieve.

Example 8

A kind of preparation method of ZSM-5 molecular sieve, its concrete steps are as follows:

(1) Dissolve solid NaOH and sodium metaaluminate (NaAlO ₂ ) with deionized water, stir and clarify, then add polyethylene glycol (PEG400) to form a clear A solution; add solid silica gel to the above solution, and stir for 30-60 minutes , continue to add TPA ⁺ guide glue, stir evenly. The molar equivalent of Al ₂ O ₃ in the above-mentioned aluminum source compound: the molar equivalent of SiO ₂ : the alkali source compound: TPAOH: guiding gel: the molar ratio of H ₂ O is 0.033: 1: 0.055: 0.1: 12, wherein SiO ₂ : The mass ratio of guiding glue: PEG400 is 1:1%:100%.

(2) Transfer the obtained reaction mixture to a high-pressure reactor for hydrothermal crystallization, and crystallize at 175°C for 12 hours. The crystallized product is filtered, washed with deionized water, dried, etc. to obtain silicon aluminum with MFI structure Zeolite molecular sieve.

Example 9

A kind of preparation method of ZSM-5 molecular sieve, its concrete steps are as follows:

(1) Dissolve solid NaOH and sodium metaaluminate (NaAlO ₂ ) with deionized water, stir and clarify, then add polyethylene glycol (PEG400) to form a clear A solution; add solid silica gel to the above solution, and stir for 30-60 minutes , continue to add TPA ⁺ guide glue, stir evenly. The molar equivalent of Al ₂ O ₃ in the above-mentioned aluminum source compound: the molar equivalent of SiO ₂ : the molar ratio of alkali source compound: TEABr: _{H 2} O is 0.033: 1: 0.055: 0.35: 12, wherein the mass of SiO ₂ : PEG400 The ratio is 1:5%. .

(2) Transfer the obtained reaction mixture to a high-pressure reactor for hydrothermal crystallization, and crystallize at 185°C for 12 hours. The crystallized product is filtered, washed with deionized water, dried, etc. to obtain a silicon-alumina containing MFI structure Zeolite molecular sieve.

Example 10

A kind of preparation method of ZSM-5 molecular sieve, its concrete steps are as follows:

(1) Dissolve solid KOH and sodium metaaluminate (NaAlO ₂ ) with deionized water, stir and clarify, then add polyethylene glycol (PEG400) to form a clear A solution; add solid silica gel to the above solution, and stir for 30-60 minutes , continue to add TPA ⁺ guide glue, stir evenly. The molar equivalent of Al ₂ O ₃ : the molar equivalent of SiO ₂ : the alkali source compound: hexamethylenediamine: the molar ratio of _{H 2} O is 0.033:1:0.055:0.35:12, wherein the mass ratio of SiO ₂ :PEG400 is 1: 20%. .

(2) Transfer the obtained reaction mixture to a high-pressure reactor for hydrothermal crystallization, and crystallize at 185°C for 12 hours. The crystallized product is filtered, washed with deionized water, dried, etc. to obtain a silicon-alumina containing MFI structure Zeolite molecular sieve.

Example 11

A kind of preparation method of ZSM-5 molecular sieve, its concrete steps are as follows:

(1) Dissolve solid KOH and sodium metaaluminate (NaAlO ₂ ) with deionized water, stir and clarify, then add polyethylene glycol (PPG2000) to form a clear A solution; add solid silica gel to the above solution, and stir for 30-60 minutes , continue to add TPA ⁺ guide glue, stir evenly. The molar equivalent of Al ₂ O ₃ : the molar equivalent of SiO ₂ : the alkali source compound: TPAOH: H ₂ O has a molar ratio of 0.033:1:0.055:0.1:12, wherein the mass ratio of SiO ₂ :PEG400 is 1:20% .

(2) Transfer the obtained reaction mixture to a high-pressure reactor for hydrothermal crystallization, and crystallize at 200°C for 12 hours. The crystallized product is filtered, washed with deionized water, dried, etc. to obtain silicon aluminum with MFI structure Zeolite molecular sieve.

Example 12

A kind of preparation method of ZSM-5 molecular sieve, its concrete steps are as follows:

(1) Dissolve solid NaOH and sodium metaaluminate (NaAlO ₂ ) with deionized water, stir and clarify, then add polyethylene glycol (PEG400) to form a clear A solution; add solid silica gel to the above solution, and stir for 30-60 minutes , continue to add TPA ⁺ guide glue, stir evenly. The molar equivalent of Al ₂ O ₃ : the molar equivalent of SiO ₂ : the molar ratio of alkali source compound: TPABr: _{H 2} O is 0.033: 1: 0.055: 0.1: 12, and the mass ratio of SiO ₂ : PEG400 is 1: 20% . .

(2) Transfer the obtained reaction mixture to a high-pressure reactor for hydrothermal crystallization, and crystallize at 185°C for 12 hours. The crystallized product is filtered, washed with deionized water, dried, etc. to obtain a silicon-alumina containing MFI structure Zeolite molecular sieve.

Example 13

A kind of preparation method of ZSM-5 molecular sieve, its concrete steps are as follows:

(1) Dissolve solid NaOH and sodium metaaluminate (NaAlO ₂ ) with deionized water, stir and clarify, then add polyethylene glycol (PEG400) to form a clear A solution; add solid silica gel to the above solution, and stir for 30-60 minutes , continue to add TPA ⁺ guide glue, stir evenly. The molar equivalent of Al ₂ O ₃ : the molar equivalent of SiO ₂ : alkali source compound: butylamine: PEG400: the molar ratio of _{H 2} O is 0.033: 1: 0.055: 0.28: 12, wherein the mass ratio of SiO ₂ : PEG400 is 1 : 20%. .

(2) Transfer the obtained reaction mixture to a high-pressure reactor for hydrothermal crystallization, and crystallize at 185°C for 12 hours. The crystallized product is filtered, washed with deionized water, dried, etc. to obtain pure silicon containing MFI structure Zeolite molecular sieve.

Example 14

The synthesis steps of the ZSM-5 molecular sieve in this example are basically the same as those in Example 4. In this example, hydrochloric acid was used as the acid source. Its crystallization temperature is 175°C, and the original ZSM-5 molecular sieve powder of the present invention can be synthesized by crystallization for 2-48 hours, and its relative crystallinity can reach 108%.

Example 15

The synthesis steps of the ZSM-5 molecular sieve in this example are basically the same as those in Example 3. In this embodiment, white carbon black is used as the silicon source. Its crystallization temperature is 175°C, and the original ZSM-5 molecular sieve powder of the present invention can be synthesized by crystallization for 2-48 hours, and its relative crystallinity can reach 108%.

Example 16

The synthesis steps of the ZSM-5 molecular sieve in this example are basically the same as those in Example 4. In this embodiment, nitric acid and aluminum nitrate are used as acid source and aluminum source respectively. Its crystallization temperature is 175°C, and the raw ZSM-5 molecular sieve powder of the present invention can be synthesized after crystallization for 2-48 hours, and its relative crystallinity can reach 102%.

Example 17

The synthesis steps of the ZSM-5 molecular sieve in this example are basically the same as those in Example 1. The crystallization temperature used in this example is 185° C., and the raw ZSM-5 molecular sieve powder of the present invention can be synthesized after crystallization for 2-48 hours, and its relative crystallinity can reach 100%.

The polyether compound is added in the synthesis of the pentasil-type zeolite molecular sieve of the present invention to accelerate the crystallization of the molecular sieve, reduce the dosage of the template agent, and synthesize the molecular sieve with relatively high crystallinity at a lower dosage of the organic template agent.

The protection content of the present invention is not limited to the above embodiments. Without departing from the spirit and scope of the inventive concept, changes and advantages that can be imagined by those skilled in the art are all included in the present invention, and the appended claims are the protection scope.

Claims (6)

1. the synthetic method of a pentasil type zeolite molecular sieve is characterized in that, aluminum source compound, alkali source compound, silicon source compound, additive, organic formwork agent and water are mixed, and stirs, and forms reaction mixture; Described reaction mixture is carried out hydrothermal crystallizing, after filtration, washing, drying obtain described pentasil type zeolite molecular sieve; Wherein, described additive is polyether compound.

2. the synthetic method of pentasil type zeolite molecular sieve as claimed in claim 1 is characterized in that, described aluminum source compound comprises sodium metaaluminate, Tai-Ace S 150, aluminum nitrate and aluminum isopropylate; Described alkali source compound comprises potassium hydroxide and sodium hydroxide; Described silicon source compound comprises silicon sol, silica gel, water glass and white carbon black; Described polyether compound comprises polyoxyethylene glycol, polypropylene glycol and contains EO and the polymkeric substance of PO structural unit; Described organic formwork agent comprises TPAOH, TPABr, amine and diamines.

3. the synthetic method of pentasil type zeolite molecular sieve as claimed in claim 1 is characterized in that, described polyether compound is SiO in whole synthetic system ₂: the polyether compound mass ratio is 1: (5-100%).

4. the synthetic method of pentasil type zeolite molecular sieve as claimed in claim 1 is characterized in that, adds Si-Al molecular sieve or guiding glue as crystal seed in described reaction mixture, SiO in the whole synthetic system ₂: the SiO2 mass ratio is 1 in the crystal seed: (0-10%).

5. the synthetic method of pentasil type zeolite molecular sieve as claimed in claim 1 is characterized in that, Al in the described aluminum source compound ₂O ₃Molar equivalent: SiO ₂Molar equivalent: alkali source compound: organic formwork agent: the mol ratio of water is (0-0.05): 1: (0.05-0.5): (0-0.5): (5-100).

6. the synthetic method of pentasil type Si-Al zeolite molecular sieve as claimed in claim 1 is characterized in that, the temperature of described hydrothermal crystallizing is 100-200 ℃, and the time is 5-48 hour.

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