CN1108214A - Synthetic method of zeolite beta (2) - Google Patents

Abstract

A method for synthesizing zeolite beta by wetting crystallization, which uses silica gel particles with any pore size and 20 to 200 meshes as the silicon source, and adds it to a solution composed of aluminum source, sodium hydroxide, tetraethylammonium cation, and water Mix well in the medium so that the surface of the silica gel particles is wetted by the solution, and crystallize at 140-170°C for 10-60 hours without seed crystals. The reaction system has the following molar ratio composition: SiO ₂ /Al ₂ O ₃ =10-100, Na ₂ O/SiO ₂ =0.01-0.1, TEAOH/SiO ₂ =0.05-0.15, H ₂ O/SiO ₂ =1-0.1 3. The method reduces the consumption of the template agent and water, accelerates the crystallization speed, reduces the production cost, and increases the output of a single kettle.

Description

The present invention relates to the synthesis method of crystalline aluminosilicate zeolite, in particular, to the synthesis method of beta zeolite.

Beta zeolite was first synthesized by the American Mobile Company in 1967 by the classic hydrothermal crystallization method (USP3,308,069). The zeolite has a unique three-dimensional (or two-dimensional) pore structure, has high catalytic activity for hydrocracking and hydroisomerization, and can be used for hydrocracking and hydroisomerization after modification or loading of certain metal components Petroleum refining and petrochemical processes such as hydrofining, hydrodewaxing, and diesel decondensation. According to the method disclosed in this patent, zeolite beta is synthesized as follows: a mixture containing Na ₂ O, Al ₂ O ₃ , TEAOH (that is, tetraethylammonium hydroxide), SiO ₂ and water is made into a slurry, and in an autoclave Crystallization reaction at 75-200°C for 3-60 days. The feed molar ratio of the reaction system is SiO ₂ /Al ₂ O ₃ =10-200, Na ₂ O/TEAOH =0.0-0.1, TEAOH/SiO ₂ =0.1-1.0, H ₂ O/TEAOH =20-75. Since the silicon source adopted in the method is a silicate solution with a large water content, the amount of template agent tetraethylammonium hydroxide is increased. Due to the high price of the organic template agent, the cost of producing zeolite beta by this method is high, which is not conducive to large-scale industrial production. At the same time, the volume of the entire reaction solution is large and the crystallization time is long, which brings about the problem of low production efficiency.

In 1986, Exxon Corporation successfully developed a new technology for synthesizing zeolite beta (EP187, 522), that is, "single-solution synthesis" technology. The specific method is: mix the solid raw materials of the precursors of SiO ₂ , Al ₂ O ₃ and Na ₂ O evenly and then mix them with tetraethylammonium hydroxide solution, and heat them at 75-150°C with or without beta zeolite seed crystals. The crystallization reaction is carried out in the presence of conditions. The feed molar ratio of the reaction system is SiO ₂ /Al ₂ O ₃ =10-200, Na ₂ O/TEA ₂ O =0.01-0.1, TEA ₂ O/SiO ₂ =0.01-0.1, H ₂ O/TEA ₂ O =25~150. Since only tetraethylammonium hydroxide is added in the form of solution in the reaction system, too much water is avoided from being introduced into the system, thereby reducing the consumption of water and tetraethylammonium hydroxide in the synthesis process, production cost and production efficiency are likely to be improved. Yet above-mentioned improvement is still not ideal enough, calculates according to the best example in this patent, every ton of beta zeolite just need consume about 1 ton of content and be the tetraethylammonium hydroxide solution of 40%; The crystallization time of β zeolite is as long as 6 to 10 days, and these shortcomings still make it difficult to carry out industrial-scale production and application of β zeolite.

In 1989, Mobile Company proposed an improved synthesis of β zeolite technology (USP4,875,056), in which a special silicon source with a certain particle size was used, which was composed of soluble silicon source solution It is prepared by adding a precipitating agent under certain conditions. In the zeolite synthesis system, tetraethylammonium bromide is used as template agent, and the crystallization reaction is carried out in the presence of seed crystals. However, this technology does not solve the problem of industrial-scale production. This is because the preparation process of the silicon source is complicated, and mordenite and ZSM-5 heterocrystals are easily produced in the crystallization reaction system. Large, only when TEA ₂ O/SiO ₂ >0.14, that is, TEAOH/SiO ₂ >0.28, the generation of miscellaneous crystals can be reduced.

Based on the above-mentioned prior art situation, the object of the present invention is to provide a new synthetic method of zeolite beta, so that the consumption of tetraethylammonium cationic template is less to reduce costs; the consumption of water is less to improve single-pot yield; The crystallization time is shorter to improve production efficiency.

The method provided by the invention is to dissolve the solid aluminum source and sodium source in the mixed solution of tetraethylammonium cation and water, then use the mixed solution to wet the surface of silica gel particles as the silicon source, and then conditions to complete the crystallization reaction. TEA ⁺ , OH ^- and other reaction materials enriched on the surface of silica gel particles first undergo crystallization reaction on the surface of silica gel particles, and then the crystallization reaction goes deep into the interior of silica gel particles layer by layer until all silica gel particles are converted into β zeolite.

According to the wet crystallization synthesis method provided by the present invention, zeolite beta is synthesized in the following way: the solid aluminum source and sodium hydroxide are dissolved in tetraethylammonium hydroxide and water to form a working solution, and the silica gel with a particle size of 20 to 200 mesh The particles are the source of silicon. Mix the silica gel with the working solution to wet the surface of the silica gel particles with the working solution. Crystallize at 140-170°C for 10-60 hours without adding additional seeds, separate the solid product, wash and dry That is, the finished product of zeolite beta. The molar ratios of the raw materials in the reaction system are as follows: SiO ₂ /Al ₂ O ₃ =10-100, preferably 10-80, Na ₂ O/SiO ₂ =0.01-0.1, TEAOH/SiO ₂ =0.05-0.15, H ₂ O/SiO ₂ =1-3.

The aluminum source used is selected from pseudo-boehmite, SB aluminum hydroxide, and aluminum hydroxide. The sodium ions in the sodium hydroxide used can be replaced by other alkali metal or alkaline earth metal ions that do not affect the reaction. The tetraethylammonium hydroxide used can be replaced by tetraethylammonium chloride, tetraethylammonium bromide, tetraethylammonium iodide and mixtures thereof. The silica gel particles used have any pore size, including coarse-pore, medium-pore and fine-pore silica gel.

The method provided by the invention uses solid particle silica gel as the silicon source, and the working solution only wets the surface of the silica gel particles to crystallize, thereby reducing the amount of organic templates used in the reaction system under the same proportioning conditions, thereby reducing the cost. And because only a small amount of water is contained in the reaction system, the single-pot output is greatly improved. Simultaneously, because the method shortens the crystallization time, it provides the possibility for realizing high-efficiency industrial production of the beta zeolite.

The zeolite prepared by the method provided by the present invention has a typical X-ray diffraction spectrum of zeolite beta, and the d value (nanometer) of its main spectral line is as follows:

1.14±0.02

0.74±0.02

0.67±0.02

0.425±0.01

0.397±0.01

0.30±0.01

0.22±0.01

The grain size of the zeolite beta prepared by the method provided by the invention can be adjusted by changing the reaction conditions, and the grain size ranges from 0.1 to 10 microns.

The beta zeolite prepared by the method provided by the invention can be converted into a hydrogen form after being roasted to remove the template agent, and then pickled, or exchanged with an ammonium solution and then roasted to form a hydrogen form for use. Various metals or their compounds, such as alkali metals, alkaline earth metals, rare earth elements, Pt, Pd, Re, Sn, Ni, W, Co and other elements or their compounds, can be introduced into it by ion exchange, impregnation or other methods to make it a Zeolite containing various metals; it can also introduce compounds of different compounds such as P, Ga, Ti, B and other elements to make it a special-purpose zeolite; it can also be removed from the zeolite framework by pickling, chemical extraction, etc. Part of the aluminum makes it have a higher ratio of silicon to aluminum. The beta zeolite synthesized by the method and its improved type can be used as catalysts, catalytic aids and adsorbents in various petroleum refining and petrochemical processes.

Accompanying drawing 1 and accompanying drawing 2 are the X-ray diffraction spectrograms of the beta zeolite that adopts the method provided by the present invention to use pseudo-boehmite and aluminum hydroxide as aluminum sources respectively. Spectra were obtained with CuKα radiation and Ni filtering.

The following examples will further illustrate the method provided by the invention.

Comparative example 1~2

Zeolite beta was prepared without seed crystals as disclosed in the examples of USP 3,308,069.

Dissolve 2 grams of sodium aluminate (product of Shanghai Reagent No. 2 Factory, including Al ₂ O ₃ 45%, Na ₂ O 55%) in 30 ml of tetraethylammonium hydroxide solution (product of Beijing Chemical Plant, 2.958N), and then mix with 81 grams of silica sol (produced by Beijing No. 90 Middle School, wherein the _SiO2 content is 24.7% by weight) was mixed and vigorously stirred to form a slurry. The molar ratios of the components in the slurry are: SiO ₂ /Al ₂ O ₃ =37.8, Na ₂ O/SiO ₂ =0.053, TEAOH/SiO ₂ =0.266, H ₂ O/SiO ₂ =13.1. Crystallize the above slurry in a reaction kettle at 150°C for two days and three days respectively, take it out for cooling, filter, wash, and dry at 110°C to obtain Zeolite Beta.

The relative crystallinity measured by X-ray diffraction method is 60% and 100% respectively (this sample is used as a benchmark).

Comparative example 3

Zeolite beta was prepared using seed crystals as disclosed in the examples of USP 3,308,069.

Mix _80-120 mesh coarse- _pore silica gel (produced by Qingdao Silica Gel Factory ₎ , sodium aluminate (product of Shanghai Reagent No. Mix, then add tetraethylammonium hydroxide and mix well. The molar ratio of each component in the reaction system is: SiO ₂ /Al ₂ O ₃ =62.4, Na ₂ O/SiO ₂ =0.04, TEAOH/SiO ₂ =0.18, H ₂ O/SiO ₂ =5.4. Crystallize the above slurry in a reaction kettle at 150°C for 6 days, take it out for cooling, filter, wash, and dry at 110°C to obtain Zeolite Beta.

The relative crystallinity measured by X-ray diffraction method is 92.0%.

Example 1~5

According to the method provided by the invention, pseudo-boehmite is used as aluminum source to prepare zeolite beta. Dissolve industrial pseudo-boehmite (produced by Shandong Aluminum Plant), sodium hydroxide (produced by Beijing Chemical Plant, chemically pure) in tetraethylammonium hydroxide aqueous solution (produced by Beijing Chemical Plant, 2.807N), with or without adding water, Add silica gel (manufactured by Qingdao Silica Gel Factory) to the above working solution and mix evenly, so that the surface of the silica gel particles is wetted by the solution, carry out crystallization reaction at 150°C, separate the solid product, wash and dry to obtain Zeolite Beta.

Various raw material consumptions and the raw material composition molar ratio in each example are listed in Table 1 in the reaction system.

The relative crystallinity of each zeolite beta sample measured by X-ray diffraction method is also listed in Table 1.

Each of the obtained zeolite beta samples had X-ray diffraction spectra as shown in FIG. 1 .

Table 1 example 1 2 3 4 5 The amount of each raw material pseudo-boehmite, gram sodium hydroxide, gram TEAOH, milliliter water, milliliter silica gel: weight, gram particle size, mesh pore size 1.51.513.04.02080～120 coarse 1.51.513.04.02080～120 coarse 1.051.514.80.027.340～60 fine 1.051.514.80.027.3100～200 fine 1.051.514.80.021.940～60 thick Crystallization reaction time, hours 40 60 twenty four twenty four 29 Raw material composition, molar ratio SiO ₂ /Al ₂ O ₂ Na ₂ O/SiO ₂ TEAOH/SiO ₂ H ₂ O/SiO ₂ 37.80.0550.1091.94 37.80.0550.1091.94 400.0570.1232.6 400.0570.1232.8 400.0570.1231.8 Relative crystallinity, % 103.6 105.6 85.6 80.0 82.3

Example 6-8

According to the method provided by the invention, the beta zeolite is prepared by using SB aluminum hydroxide as an aluminum source.

Dissolve SB aluminum hydroxide (imported from Germany) and sodium hydroxide in tetraethylammonium hydroxide aqueous solution, then add a certain amount of water, add silica gel to the above working solution and mix evenly, so that the surface of silica gel particles is wetted by the solution , Carry out crystallization reaction at 150°C, separate the solid product, wash and dry to obtain β zeolite.

Various raw material consumptions and the raw material composition molar ratio in the reaction system are listed in Table 2 in each example.

The relative crystallinity of each zeolite beta sample measured by X-ray diffraction method is also listed in Table 2.

Each of the obtained zeolite beta samples had X-ray diffraction spectra as shown in FIG. 1 .

Table 2 example 6 7 8 The amount of each raw material SB aluminum hydroxide, gram sodium hydroxide, gram TEAOH, milliliter water, milliliter silica gel: weight, gram particle size, mesh pore size 0.740.9513.23.62080～120 coarse 1.01.310.85.12080～120 coarse 1.81.913.23.32080～120 coarse Crystallization reaction time, hours 20 35 20 Raw material composition, molar ratio SiO ₂ /Al ₂ O ₂ Na ₂ O/SiO ₂ TEAOH/SiO ₂ H ₂ O/SiO ₂ 620.040.1222.2 460.0540.1002.2 250.0790.1222.6 Relative crystallinity, % 102.0 95.4 94.2

Examples 9-13

According to the method provided by the invention, the beta zeolite is prepared by using industrial aluminum hydroxide as an aluminum source.

Dissolve industrial aluminum hydroxide (produced by Shandong Aluminum Factory) and sodium hydroxide in tetraethylammonium hydroxide aqueous solution, add or not add water, add silica gel to the above working solution and mix evenly, so that the surface of silica gel particles is moistened by the solution Wet, carry out crystallization reaction at 150°C, separate the solid product, wash and dry to obtain β zeolite.

Various raw material consumptions and the raw material composition mol ratio in the reaction system are listed in Table 3 in each example.

The relative crystallinity of each zeolite beta sample measured by X-ray diffraction method is also listed in Table 3.

Each of the obtained zeolite beta samples had X-ray diffraction spectra as shown in FIG. 2 .

table 3 example 1 2 3 4 5 The dosage of each raw material is industrial aluminum hydroxide, gram sodium hydroxide, gram TEAOH, milliliter water, milliliter silica gel: weight, gram particle size, mesh pore size 1.41.513.04.02080～120 coarse 1.41.513.04.02080～120 coarse 0.91.313.23.72080～120 coarse 1.51.514.80.027.340～60 fine 1.51.514.80.027.2100～200 fine Crystallization reaction time, hours 35 60 29 twenty four twenty four Raw material composition, molar ratio SiO ₂ /Al ₂ O ₂ Na ₂ O/SiO ₂ TEAOH/SiO ₂ H ₂ O/SiO ₂ 37.80.0550.1091.94 37.80.0550.1091.94 60.00.0540.1232.6 35.00.0550.1381.8 35.00.0550.1381.8 Relative crystallinity, % 100.6 103.9 100.0 86.6 80.6

Examples 14-16

According to the method provided by the invention, the beta zeolite is prepared by using aluminum hydroxide as an aluminum source.

Dissolve reagent aluminum hydroxide (produced by Beijing Chemical Reagent No. 2 Factory, containing 57.0% Al ₂ O ₃ ) and sodium hydroxide in tetraethylammonium hydroxide aqueous solution, add a certain amount of water, and add silica gel to the above working solution Mix evenly, make the surface of the silica gel particles wet with the solution, carry out crystallization reaction at 150°C, separate the solid product, wash and dry to obtain zeolite beta.

Various raw material consumptions and the raw material composition molar ratio in each example are listed in Table 4 in the reaction system.

The relative crystallinity of each zeolite beta sample measured by X-ray diffraction method is also listed in Table 4.

Each of the obtained zeolite beta samples had X-ray diffraction spectra as shown in FIG. 2 .

Table 4 example 14 15 16 Amount of raw materials Reagent aluminum hydroxide, gram sodium hydroxide, gram TEAOH, milliliter water, milliliter silica gel: weight, gram particle size, mesh pore size 1.10.9513.23.420.080～120 thick 2.11.310.84.820.080～120 coarse 2.11.913.23.320.080～120 coarse Crystallization reaction time, hours 20 40 20 Raw material composition, molar ratio SiO ₂ /Al ₂ O ₂ Na ₂ O/SiO ₂ TEAOH/SiO ₂ H ₂ O/SiO ₂ 62.00.040.1222.2 25.00.0480.092.0 25.00.0710.112.0 Relative crystallinity, % 102.3 100.0 96.8

Claims (6)

1, a kind of method of synthetic β zeolite, it is characterized in that making silica gel particle surface wetting by the reaction working solution of forming by aluminium source, sodium hydroxide, tetraethyl ammonium hydroxide, water, in 140～170 ℃ of following crystallizations 10～60 hours, this reaction system had following mol ratio and forms: SiO ₂/ Al ₂O ₃=10～100, Na ₂O/SiO ₂=0.01～0.1, TEAOH/SiO ₂=0.05～0.15, H ₂O/SiO ₂=1～3.

2, in accordance with the method for claim 1, it is characterized in that said silica gel particle is any aperture and has 20～200 purpose granularities.

3, in accordance with the method for claim 1, it is characterized in that said aluminium source is selected from pseudo-boehmite, SB aluminium hydroxide, aluminium hydroxide.

4, in accordance with the method for claim 1, it is characterized in that the sodium ion in the said sodium hydroxide can be replaced by other basic metal or alkaline-earth metal ions that does not influence reaction.

5, in accordance with the method for claim 1, it is characterized in that said tetraethyl ammonium hydroxide can be replaced by etamon chloride, tetraethylammonium bromide, tetraethyl ammonium iodide and composition thereof.

6, in accordance with the method for claim 1, it is characterized in that SiO in the said reaction system ₂/ Al ₂O ₃=10～80.

Images