 |
Dalian Institute of Chemical Physics, Chinese Academy of Sciences The Huang Shengjun Research Team of Low Temperature Molecular Sieve Acid-base Catalysis and Fine Chemicals Synthesis Research Group has realized the bridging of desiliconization-desilication process for the first time in the study of controllable adjustment of silicalite molecular sieves.
Molecular sieves have a wide range of uses in modern petroleum refining and chemical industries. The adjustment of the acidity, pore structure and other properties of molecular sieves is a hot topic in the field of molecular sieve catalytic applications. The “dealuminum†post-treatment revolves around the existing composition and structural units of the silica-alumina molecular sieve and adjusts the aluminum center. This technology has a history of more than half a century of research and development. Its representative method is widely used in water vapor treatment. In the industrial silica aluminosilicate catalyst production process. However, the "dealuminization" method has limitations in the adjustment of the properties of the silica-alumina molecular sieves at the micropore scale. In recent years, the "silicone removal" post-treatment method that has gradually emerged to adjust the silicon center can adjust the properties of the molecular sieve on the mesoporous scale. Since this method is subject to the existing aluminum content and particle size of the silica-alumina molecular sieve, its application range is also limited.
For the first time, the research team of the Huang Shengjun team successfully bridged the “de-aluminization†and “silicon de-siliconization†methods and overcome the high aluminum content and large particle size of the molecular sieve through a simple and easy-to-implement combination of water vapor treatment and alkali treatment. Restricted, a concentrated and controllable microporous-mesoporous multi-level pore structure was successfully constructed in the high-aluminum content MFI molecular sieve, and it retains a rich acid site and good hydrothermal stability. This study breaks the currently unrestricted “desiliconization†and “siliconization†restrictions that are currently followed at home and abroad, and provides a richer set of tools for the development of industrial catalyst preparation methods that are low-cost, highly operational, and can be applied in large scale. box". The study also believes that the structure, position and interaction of skeletons of non-skeletal Al species play an important role in the modification of molecular sieves, which brings a new perspective to the traditional classical research of silica-alumina molecular sieves.
The relevant research results were published in "German Applied Chemistry." The study was funded by the National Natural Science Foundation of China.
fencing,fence panel,wire mesh fence
Hebei Haiao Wire Mesh Products Co., Ltd. , https://www.haiaowiremeshfencing.com