Preparation method of metal ion dosed monodisperse mesoporous silicon dioxide spherical nanoparticles

Abstract

The invention discloses a preparation method of metal ion dosed monodisperse mesoporous silicon dioxide spherical nanoparticles. In the method, a template is hexadecyl trimethyl p-toluene ammonium sulphonate, an alkali source is organic micromolecular amine, a silicon source is tetra-allkyl silicate ester, introduced metal heteroatoms comprise Ti, Al, Zr and V; molar composition of raw materials are as follows: the molar ratio of the silicon source, the template, the organic micromolecular amine, the metal heteroatom alkoxide and water is 1:0.03-0.06:0.001-8.0:0.01-0.1:20-1000; and the particle size of the particles can be effectively regulated and controlled within a range of 20-200 nm. According to the invention, by using the hexadecyl trimethyl p-toluene ammonium sulphonate with extremely low concentration as template molecules and using the organic micromolecular amine with lower usage as the alkali source, highly monodisperse mesoporous silicon dioxide spherical nanoparticles containing different metal heteroatoms are synthesized. The prepared catalytic material shows higher catalytic performance in the olefin epoxidation reaction. The synthesis method disclosed by the invention, which is an environment friendly synthesis method, has the advantages of simplicity, short period, low cost and good repeatability.

Description

technical field [0001] The present invention relates to a method for preparing mesoporous molecular sieves, in particular to a method for preparing highly monodisperse mesoporous nano-microspheres containing heterometal atoms at extremely low cost. The obtained catalytic material is used in the olefin epoxidation reaction showed high catalytic performance. Background technique [0002] Ordered mesoporous materials refer to mesoporous materials with regular and ordered channels. The synthesis of mesoporous materials began as early as 1971. Before 1990, Kuroda in Japan had also used layered silicate in the surface activity. The synthesis of mesoporous materials began with the transformation in the presence of an agent. The report by Mobil in 1992 attracted widespread attention and was considered to be the real beginning of the synthesis of mesoporous materials. Mobil used surfactants as templates to synthesize the M41S series of mesoporous materials, including MCM-41 (hexagon...

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Problems solved by technology

The current main synthetic strategies for the synthesis of mesoporous silica nanoparticles (MSNs) include: using a single CTAB cationic surfactant (Angew. Chem. Int. Ed., 2002, 2151, 2317.), in the early stage of the reaction, through a large number of Diluted with water to quench particle growth, thus preparing mesoporous silica nanoparticles with a size of less than 100 nm, but the particle shape is irregular and the size distribution is very inhomogeneous; through the improved St?ber method (J. Phys . Chem. B 2004, 108, 20122.), using ethanol as a co-surfactant of CTAB cationic surfactant can prepare highly monodisperse mesoporous SiO 2 nanoparticles, but often larger than 100 nm in size; Bein by using triethanolamine (TEAH 3 ) to replace inorganic bases to synthesize mesoporous nanoparticles with a size of less than 200 nm (Adv. Funct. Mater. 2007, 17, 605.), but the amount of triethanolamine (TEAH3) is extremely large, and high-speed centrifugation is required to obtain The final particle; Kuroda recently reported a new synthetic strategy to prepare mesoporous SiO with a size smaller than 50 nm 2 Nanoparticles, but the molar ratio of CTAB / TMOS is greater than 0.5, the cost of synthesis is extremely high and the surfactant can only be removed through a complicated dialysis process (Chem. Commu., 2009, 5094.); Chinese patent CN1923684A utilizes dodecyl Using sodium sarcosinate as a template and (3-aminopropyl)trimethoxysilane as a co-structure directing agent, SiO with uniform size and controllable size was synthesized. 2 Nanoparticles, but the cost of synthesis is relatively high; the synthesis strategy of mixed templates can also be used to synthesize highly monodisperse mesoporous nanoparticles, but the expensive price of surfactants limits its wide application (Chemical Journal of Chinese Universities, 2011, 32, 560.)

In addition, the synthesis of mesoporous nanoparticles often only focuses on the synthesis of pure silicon-based mesoporous materials, and the synthesis of mesoporous nanoparticles containing heterometal atoms has not been reported yet.

It can be seen from the above reports that the existing synthetic methods have disadvantages such as single component, harsh conditions, high cost, heavy pollution, and unfavorable for large-scale production.

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