54results about How to "Reduce the ratio of silicon to aluminum" patented technology

The invention discloses a ZSM-48 molecular sieve with a low silica-alumina ratio and a preparation method thereof. The molecular sieve has the following properties: the molar ratio of silica to alumina is 25-50; the specific surface is 250-400 m2 / g; the pore volume is 0.25-0.35 cm3 / g; the average pore size is 3-5 nm. The preparation method comprises the following steps: (1) well mixing a seed crystal S, a template R, a silicon source, an aluminium source, sodium hydroxide and water to prepare a reaction mixture, wherein the composition of the reaction mixture is as follows: on a basis of oxide, the molar ratio of R to SiO2 is 0.05-0.2, the molar ratio of SiO2 to Al2O3 is 30-50, the molar ratio of Na2O to SiO2 is 0.06-0.1, the molar ratio of H2O to SiO2 is 15-23, the mass ratio of S to SiO2 is 0.05-0.5, S is the ZSM-48 molecular sieve, and R is 12-crown ether-4; (2) performing hydrothermal crystallization of the reaction mixture prepared in step (1) at 150-170 DEG C for 4-8 days, performing filtration, washing, drying, and roasting of the crystallization product to obtain the ZSM-48 molecular sieve with a low silica-alumina ratio. The ZSM-48 molecular sieve prepared by the method of the invention has a low silica-alumina ratio, and has good application prospects in technical fields of isodewaxing and the like.

The invention discloses a modified Y molecular sieve and a preparation method thereof, which have the following properties: the silicon-aluminum ratio of the bulk phase is 10-70, wherein the silicon-aluminum ratio of the surface layer is 7-30, and the silicon-aluminum ratio of the surface layer is lower than the silicon-aluminum ratio of the bulk phase Ratio 5~40, wherein the surface layer refers to the thickness range from the outer surface of the molecular sieve to the inside of 5~400nm; the unit cell constant of the modified Y molecular sieve is 2.425~2.455nm; the specific surface area of ​​the modified Y molecular sieve is 600~900m2 / g, the pores Content 0.20~0.70ml / g; infrared acid content 0.3~1.5mmol / g. The preparation method of the modified Y molecular sieve of the present invention is as follows: the Y molecular sieve after ammonium exchange is subjected to primary dealumination treatment, rapid drying, carbon deposition reaction, high-temperature roasting treatment, and then secondary dealumination treatment, drying, and charcoal burning treatment, A modified Y molecular sieve is obtained. The silicon-aluminum ratio of the surface layer of the molecular sieve of the invention is lower than that of the bulk phase, and has broad application prospects in the hydrocracking reaction process.

The invention discloses a modified Y-Beta composite molecular sieve as well as a preparation method and application thereof. The preparation method comprises the following steps of under a stirring condition, adding a Y-Beta composite molecular sieve into a pressure container full of an organic base solution, sealing a system, pressurizing to 0.2 to 1.0MPa, then heating to 50 to 90 DEG C, treating for 0.5 to 3 hours at constant temperature, depressurizing, carrying out suction filtration, drying, and roasting to obtain the modified Y-Beta composite molecular sieve. The modified Y-Beta composite molecular sieve prepared through the method has mesopore pore size distribution with a larger size, can provide more reaction spaces for macromolecules, and is beneficial to improving a catalytic performance of the molecular sieve, simple in the preparation method, and applicable to industrial application.