Molecular sieve manufacturer explains the characteristics of Y-type molecular sieves

Not all molecular sieve materials can grow large enough single crystals. In fact, among the 50 reported molecular sieve structures, less than 1/3 of the molecular sieve materials can be prepared into large single crystals. For those molecular sieve materials that cannot be prepared as large single crystals, only small-sized polycrystalline samples can be used for structure determination, and the X-ray diffraction spectra of single crystals and polycrystals often show severe peak overlap. Peak overlap is a big problem for polycrystalline structure analysis, which directly leads to erroneous measurements of diffraction intensities. Therefore, structural analysis methods that are highly dependent on diffraction intensity are generally not directly applicable to polycrystalline diffraction data.

Molecular sieves can be divided into small pores, medium pores, large pores and super large pores according to the number of pore rings. Small pore molecular sieves (such as LTA, SOD and GIS molecular sieves) have 8 TO4 tetrahedra with a pore size of about 4.0A; mesoporous molecular sieves (such as MFI) ) has 10 TO4 tetrahedra. The aperture is about 5.5A; such as FAU, MOR and *BEA, the channel window is surrounded by 12 TO4 tetrahedra, the pore size is about 7.5A, and the molecular sieve with more than 12 T atoms around the channel window is called superporous molecular sieve.

Y-type molecular sieve is mainly used for gas drying, separation and purification, as well as catalyst and catalyst carrier for petroleum processing. Zeolite molecular sieve has become an important adsorption separation and catalytic material in oil refining, petrochemical, coal chemical and a large number of fine chemical industries.

The framework of Y-type molecular sieve can be regarded as composed of finite structural units or infinite structural units (such as chains or layers), and the finite structural units are called secondary structural units.

Repeat this process until the calculated diffraction intensity is consistent with the observed diffraction intensity, and the obtained electron density corresponds to the real atomic distribution in the crystal. Practice has shown that the charge inversion method is especially suitable for structures with uneven electron density distribution, However, it has many advantages that other methods cannot match, such as fast calculation speed, no need to determine the space group in advance, and high latitude structure can be calculated. These advantages make the charge inversion method become an important structural analysis method in the field of molecular sieves in the near future. Hunan Providence New Materials Co., Ltd is a professional molecular sieve manufacturer which can provide USY zeolite, NaY zeolite, REY zeolite, ZSM-5 zeolite, welcome to consult.