Composite mesoporous molecular sieve solid superacid and preparation method thereof

Abstract

The invention relates to a composite mesoporous molecular sieve solid superacid and a preparation method thereof. According to the method, a home-made mesoporous molecular sieve is used as a carrier, a sol-gel method and an impregnation method are adopted to dope TiO2 and load SO4<2-> to obtain the novel molecular sieve loaded oxide solid superacid SO4<2-> / TiO2 / MAS-5 which is used as a catalyst to prepare propylene glycol monomethyl ether acetate (PMA) by taking propylene glycol monomethyl ether (PM) and acetic acid (HAc) as materials for esterification reaction so as to achieve probe reaction, thus optimizing the formula and loading conditions of TiO2 and SO4<2->. Compared with existing SO4<2-> / TiO2 solid superacid catalysts, the catalyst disclosed by the invention has the advantages of high acid strength, high catalytic activity, large specific surface area, long service life and good stability, and has wide industrial application prospect.

Description

technical field [0001] The invention relates to a preparation method of a novel solid superacid, in particular to a composite mesoporous molecular sieve solid superacid and a preparation method thereof. Background technique [0002] Acid catalysis has important applications in chemical reactions. Early acid catalysts were liquid acids such as sulfuric acid and phosphoric acid. Although this kind of acid catalyst has quite high catalytic activity at lower temperature, it is not suitable for acid-catalyzed reaction at higher temperature. At the same time, there are many problems such as easy corrosion of equipment, environmental pollution, and difficulty in catalyst post-treatment. Since 1979, Japanese scientists Hino et al. reported the first M x o y Since the solid superacid, people's research on the solid superacid has been deepening. Solid super acid is a new type of green catalytic material, which can replace the traditional liquid acid catalyst and has good catalytic...

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Problems solved by technology

[0004] Although solid superacids have many advantages, there are still deficiencies in the application process: ①Compared with traditional acid catalysts, solid superacids have lower acid center density, lower activity, and smaller specific surface area, so the reaction reaches equilibrium under the same conditions. long; ②The acid strength of different solid superacids varies greatly, and the adaptability to different reaction systems is different; ③SO 4 2- It is easy to lose, so the service life of the catalyst is short; ④ In the organic reaction, there is a phenomenon that the surface of the catalyst is easy to coke and deactivate

[0010] The traditional concentrated sulfuric acid catalyst is used in the synthesis process, and there are problems such as serious corrosion of equipment by concentrated sulfuric acid, complicated post-reaction treatment, waste residue, and environmental pollution by waste liquid; the use of p-toluenesulfonic acid solid acid catalyst has problems such as small specific surface area of ​​the catalyst , low catalytic activity, easy loss of active components resulting in low catalytic life, etc.

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