CN1113811C - Preparation method of mesonic pore molecular sieve carrier material - Google Patents

Abstract

The invention belongs to the technical field of inorganic nanometer materials, and in particular relates to a method for preparing a mesoporous molecular sieve carrier material from a diblock polymer. It is a preparation method of hydrothermal synthesis at 100°C under acidic conditions, using polyoxyethylene-polyoxybutylene diblock macromolecule surfactant as a template. The method is suitable for preparing a mesoporous silicon oxide material with a two-dimensional hexagonal structure with a high degree of order and a large specific surface area and a layered silicon oxide material with a high degree of order. These new materials can be used as catalysts, catalyst supports, adsorption films, organic-inorganic composites, sensors, and chromatographic fillers.

Description

A kind of preparation method of mesoporous molecular sieve carrier material

technical field

The invention belongs to the technical field of polymer materials, and in particular relates to a preparation method of a mesoporous molecular sieve carrier material.

technical background

Mesoporous materials synthesized by surfactants as templates have broad application prospects in the fields of macromolecule conversion, catalysis, as catalyst supports, separation and purification of biomacromolecules, miniaturization of electronic devices, and chromatographic fillers.

A series of new mesoporous materials have been synthesized by using various polyethylene oxide-polypropylene oxide-polyethylene oxide (PE0-PPO-PEO) triblock polymers as templates. These include: hexagonal (H ₁ ), layered (L _α ) and cubic (I ₁ ) symmetries. However, the synthesis of silica nano-catalyst supports using diblock polymers as templates has not been reported in the literature. Previous attempts to synthesize porous silica materials with PEO-PPO diblock polymers were unsuccessful. The reason may be that the hydrophilic/lipophilic difference between the two-block polymer surfactant blocks is too small, and the synthesis medium is too acidic.

Contents of the invention

The purpose of the present invention is to use two-block macromolecule-polyethylene oxide-polyoxybutylene (PEO-PBO) as a template agent to synthesize a mesoporous molecular sieve carrier material with large pore size and high degree of order.

The preparation method of the mesoporous molecular sieve carrier material proposed by the present invention is to synthesize silicon oxide under hydrothermal conditions using polyoxyethylene-polyepoxybutylene diblock polymer surfactant as a template in a strong acid medium The method of mesoporous molecular sieve, its specific steps are as follows:

1. Obtaining mesoporous molecular sieve gel: add a certain amount of two-block polymer surfactant polyoxyethylene-polyoxybutylene (EO _m BO _n ) into the acid solution, stir well, the surface used The molar ratio of active agent to acid is 1:1500-1:60000, and a magnetic stirrer can be used for stirring; after it is completely dissolved, add silicon source or aluminum source, and the molar ratio of silicon source or aluminum source to surfactant is 240 : 1-5000: 1; continue to stir until a large amount of white precipitates are formed; at this time, the temperature is kept at 15-80°C, which will vary depending on the synthetic material;

2. Hydrothermal treatment: transfer the mixture obtained in step 1 to a polytetrafluoroethylene hydrothermal kettle, and let it stand at 80-150°C for 8-72 hours;

3. Obtaining the mesoporous molecular sieve carrier material: cooling the mixture obtained in step 2 at room temperature, then filtering, washing, and drying at room temperature; and then roasting at 450-650° C. for 4-6 hours to obtain a white powder carrier material.

The carrier material prepared in the present invention can be silicon oxide to change the reaction source, or aluminum oxide can be prepared.

In the present invention, the diblock polymer surfactant used is EO _m BO _n type surfactant, m/n can vary in the range of 5-0.5, and the molecular weight varies from 1000 to 100000.

The silicon source used in the present invention may be one of ethyl orthosilicate, methyl orthosilicate, propyl orthosilicate, sodium orthosilicate and silica sol.

The acidic medium used in the present invention can be one of aqueous solutions of hydrochloric acid, sulfuric acid, nitric acid and hydrobromic acid.

The mesoporous material obtained in the present invention has a two-dimensional hexagonal (H ₁ ) and layered structure (L _α ).

The pore size of the mesoporous material obtained in the present invention can be adjusted by changing the m/n value of the surfactant, and the range can be from 3nm to 40nm.

Detailed ways

Example 1, the preparation of a hexagonal silica mesoporous material, the specific steps are as follows: dissolve 0.4 g of EO ₁₆ BO ₁₀ (BL50-1500) in 30 g of 2M hydrochloric acid, stir at room temperature, and wait for the After dissolving, add 3 grams of ethyl orthosilicate. After stirring at room temperature for 24 hours, it was placed in an oven at 100° C. and aged for 24 hours. After taking it out, it was cooled, filtered, and washed to obtain a white solid, which was dried at room temperature; finally, it was burned in a muffle furnace at 550° C. for 6 hours to obtain the final product. According to the characterization, the material is a mesoporous silica material with channels arranged in a two-dimensional hexagonal structure, the unit cell parameter is 9.26 nm (d ₁₀₀ value is 8.02 nm), and the pore size is 6.0 nm with a single distribution and 902 m ² /g High specific surface area and pore volume of 1.03cm ³ /g. The calcined product also has a spherical macroscopic morphology. These spheres have a uniform diameter, around 3 microns.

Example 2, preparation of a layered silica material: 7 grams of EO ₁₆ BO ₁₀ (BL50-1500) was added to 30 grams of 2M sulfuric acid, stirred at room temperature, and 3 grams of orthosilicic acid was added after it was dissolved ethyl fat. After stirring at room temperature for 24 hours, a homogeneous solution formed. Transfer the solution to a watch glass and air dry for several days. The X-ray diffraction (XRD) pattern of the product at this time shows three sharp diffraction peaks, corresponding to d values of 8.82, 4.41 and 3.01 nm, which is a typical layered structure. After the collected solid was burned in a muffle furnace at 600°C for 5 hours, the layered structure collapsed due to the removal of polymers, which in turn led to the disappearance of all diffraction peaks.

Example 3, the preparation of a hexagonal silica mesoporous material, the specific steps are as follows: dissolve 0.4 g of EO ₁₆ BO ₁₀ (BL50-1500) in 30 g of 2M hydrochloric acid, stir at room temperature, and wait for the After dissolving, add 2.5 grams of methyl orthosilicate. After stirring at room temperature for 15 hours, it was placed in an oven at 100° C. and aged for 24 hours. After taking it out, it was cooled, filtered, and washed to obtain a white solid, which was dried at room temperature; finally, it was burned in a muffle furnace at 450° C. for 6 hours to obtain the final product. According to the characterization, the material is a mesoporous silica material with channels arranged in a two-dimensional hexagonal structure, the unit cell parameter is 9.32 nm (d ₁₀₀ value is 8.07 nm), and the pore size is 6.0 nm with a single distribution and 884 m ² /g High specific surface area and pore volume of 1.01cm ³ /g. The calcined product also has a spherical macroscopic morphology. These spheres have a uniform diameter, around 2.5 microns.

Example 4, the preparation of a fibrous hexagonal silica mesoporous material, the specific steps are as follows: 0.4 grams of EO ₁₆ BO ₁₀ (BL50-1500) was dissolved in 30 grams of 2M hydrochloric acid, stirred at room temperature, After it dissolves, add 3 grams of orthobutyl silicate. After stirring at room temperature for 24 hours, it was placed in an oven at 100° C. and aged for 24 hours. After taking it out, it was cooled, filtered, and washed to obtain a white solid, which was dried at room temperature; finally, it was burned in a muffle furnace at 600°C for 4 hours to obtain the final product. According to the characterization, the material is a mesoporous silica material with channels arranged in a two-dimensional hexagonal structure, the unit cell parameter is 9.28 nm (d ₁₀₀ value is 8.03 nm), and the pore size is 6.0 nm with a single distribution and 842 m ² /g High specific surface area and pore volume of 0.97cm ³ /g. The calcined product also has a fibrous macroscopic morphology. These fibers have a uniform diameter, around 4 microns, with a high aspect ratio (>10).

Claims (4)

1, a kind of preparation method of mesonic pore molecular sieve carrier material is characterized in that concrete synthesis step is as follows:

(1) the poly-oxyethylene of a certain amount of two block macromolecular tensio-active agents-poly-epoxy butylene is joined in the solution of acid, fully stir, tensio-active agent is 1 with the mol ratio of acid: 1500-1: 60000; After treating that it dissolves fully, add silicon source or aluminium source, the mol ratio of aluminium source or silicon source and tensio-active agent is 240: 1-5000: 1; Stir, until there being a large amount of white precipitates to generate, the temperature of this moment remains on 15-80 ℃, obtains the mesopore molecular sieve gel;

(2) will transfer in the water heating kettle by the mixture that step 1 obtains, leave standstill 8-72 hour at 80-150 ℃;

(3) mixture that step 2 is obtained cools off under room temperature, filters then, washing, drying at room temperature; In 450-650 ℃ of roasting 4-6 hour, promptly obtain the solid support material of white powder again.

2, the preparation method of mesonic pore molecular sieve carrier material according to claim 1 is characterized in that m/n is within the 5-0.5 scope in the poly-oxyethylene of the tensio-active agent of being represented by EOmBOn-poly-epoxy butylene, and molecular weight is 1000 to 100000.

3, the preparation method of mesonic pore molecular sieve carrier material according to claim 1 is characterized in that the silicon source of being adopted is a kind of of tetraethoxy, methyl silicate, positive silicic acid propyl ester, sodium metasilicate and silicon sol.

4, the preparation method of mesonic pore molecular sieve carrier material according to claim 1 is characterized in that the acidic medium that is adopted is a kind of in hydrochloric acid, sulfuric acid, nitric acid and the hydrobromic aqueous solution.