NaY MOLECULAR SIEVE WITH ALUMINUM-ENRICHED SURFACE AND ITS PRODUCTION METHOD Russian patent published in 2023 - IPC B01J29/08 C01B39/24 

FIELD: chemistry.

SUBSTANCE: present invention relates to a NaY molecular sieve with an aluminum-enriched surface, a method for its production, a method for the production of a modified Y-type molecular sieve, and a modified Y-type molecular sieve. The NaY molecular sieve with an aluminum-enriched surface has an Al distribution index D: 1.01≤D≤10, where D=Al (S)/Al (C), Al (S) is an aluminum content on the surface and in the area from 2 to 6 nm below the surface of the molecular sieve, when measured by X-ray photoelectron spectroscopy (hereinafter – XPES), and Al (C) is an aluminum content of the entire molecular sieve, when measured by XPES; and it has a molar ratio of SiO₂/Al₂O₃ on the surface from 1 to 10 and SiO₂/Al₂O₃ in a volumetric phase from 2 to 20. The method for the production of a NaY molecular sieve includes following stages: a) mixing of structure-forming substance with the first silicon source to obtain the first mixture, wherein a molar composition of structure-forming substance is Na₂O:Al₂O₃:SiO₂:H₂O=(3-50):1:(3-50):(100-600); b) mixing of the first mixture with the second silicon source, an aluminum source, and water to obtain the second mixture, wherein a molar composition of the second mixture is Na₂O:Al₂O₃:SiO₂:H₂O=(1-10):1:(5-50):(100-600); c) implementation of hydrothermal crystallization of the second mixture and collection of a solid product; moreover, in terms of SiO₂, the mass ratio of the first silicon source and the second silicon source is 1:(0.001-20). The method for the production of a modified Y-type molecular sieve includes the above-mentioned stages (a), (b), and (c), as well as d. introduction of the NaY molecular sieve into reaction with ammonium, hydrothermal treatment, dealuminating, and addition of silicon dioxide. The resulting modified Y-type molecular sieve contains mesopores on a surface, has a molar ratio of SiO₂/Al₂O₃ in a volumetric phase from 10.0 to 13.0, the total pore volume according to the BET method of not less than 0.38 cm³/g, a volume of secondary pores according to the BET method of not less than 0.06 cm³/g, and unit cell parameters: a=b=c=2.44-2.46 nm.

EFFECT: provision of a NaY molecular sieve with an aluminum-enriched surface, which has a greater aluminum distribution gradient from a surface to a center of a particle than traditional NaY molecular sieves, as well as a simple and easy method for the production of a NaY molecular sieve.

32 cl, 3 dwg, 1 tbl, 16 ex