METHOD FOR PRODUCING CRYSTALLINE MEL-TYPE ZEOLITE AND MEL-TYPE ZEOLITE Russian patent published in 2023 - IPC C01B39/36 C01B39/04 B01J29/40 

FIELD: synthesis of zeolites.

SUBSTANCE: used as components of catalysts used in oil refining, petrochemistry and organic synthesis processes. The method for producing MEL-type zeolite includes preparing a precursor, its crystallization at elevated temperatures, washing and drying the resulting crystals. The preparation of the precursor is carried out by impregnating solid particles of mesoporous or meso-macroporous silica gel, having a size of 0.5-5 mm, with a reaction mixture that provides the following molar ratios of components in the precursor: SiO₂:Al₂O₃ not less than 48, Me₂O:SiO₂ from 0.023 to 0.085, where Me is an alkali metal oxide, R:SiO₂ from 0.025 to 0.068, where R is an organic template suitable for crystallization of MEL-type zeolite. The precursor is kept in a closed container and dried at room temperature until the residual moisture content provides a molar ratio of H₂O:SiO₂ in the range from 0.28 to 2.78. Then the precursor is crystallized in the absence of free water at 90-160°C. When using mesoporous silica gel as a source of SiO₂, the target product is a powder consisting of isolated crystals of MEL-type zeolite with a size of 0.1-2.0 μm. When using meso-macroporous silica gel as a source of SiO₂, the target product is granules 0.5-5 mm in size, consisting of intergrowths of MEL-type zeolite crystals of 0.2-5 μm in size. Options of the resulting crystalline zeolites are also proposed.

EFFECT: group of inventions makes it possible to obtain MEL-type zeolite with high performance characteristics while increasing the degree of conversion of the precursor into zeolite, simplify the process, reduce its duration and energy consumption, and reduce water consumption.

14 cl, 4 dwg, 2 tbl, 30 ex