Beta zeolite molecular sieve and amine-free synthetic method thereof

Abstract

The invention provides a Beta zeolite molecular sieve and an amine-free synthetic method thereof, and belongs to the technical field of molecular sieve preparation. The amine-free synthetic method of the Beta zeolite molecular sieve comprises the following steps: gel forming, crystallization and aftertreatment, wherein sodium hydroxide is taken as an alkali source, and the seed crystal adopts the Beta zeolite molecular sieve; and in the raw materials, the mole ratio of SiO2 to Al2O3 ranges from 15 to 30, the mole ratio of Na2O to SiO2 ranges from 0.14 to 0.34, and the mole ratio of H2O to SiO2 ranges from 16 to19. The amine-free synthetic method of the Beta zeolite molecular sieve does not use an organic template, the aftertreatment of the molecular sieve is convenient, and the production process is environment-friendly. The Beta zeolite molecular sieve with good crystallinity can be stilled obtained while the ratio of silicate to aluminum in the raw materials is reduced, and application to industrial production is facilitated.

Description

technical field [0001] The invention relates to the technical field of molecular sieve preparation, in particular to a Beta zeolite molecular sieve and an amine-free synthesis method thereof. Background technique [0002] Beta zeolite molecular sieve was synthesized by Mobil Company of the United States in 1967. It consists of a twelve-membered ring channel with a diameter of 0.56 nm and two twelve-membered ring channels with a diameter between 0.66-0.7 nm to form a three-dimensional crossed twelve-membered ring channel structure. , suitable structure and strong acidity make it widely used as a catalyst or additive in petroleum refining and petrochemical fields. [0003] But under normal conditions, Beta zeolite molecular sieves are formed in the presence of tetraethylammonium hydroxide. Not only does it increase the cost, but the roasting treatment before use will also bring about environmental unfriendliness. Patent ZL200810050456.3 gives a method called "method for synt...

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Problems solved by technology

The method disclosed in this invention is to use white carbon black as a silica source, sodium aluminate as an alumina source, sodium hydroxide as an alkali metal oxide source, use deionized water as a solvent, and add SiO 2 / Al 2 o 3 =22~25, Beta zeolite whose mass is 5~20% of silica source is used as seed crystal, crystallized at 130~150°C for 17~21h, wherein the molar ratio of silica to alumina is limited to SiO 2 / Al 2 o 3 =31.4~40.3; Literature (Chem.Mater.2009, 21, 4184~4191; Chem.Asian J.2010, 5, 2182~2191) expands the silicon-aluminum ratio of the Beta molecular sieve synthesized by the seed-directed method to a higher range to SiO 2 / Al 2 o 3 =40~100, it is believed that although this seed-directed method prepares the SiO 2 / Al 2 o 3 Only 10 to 14, but the feed SiO in the reaction mixture species 2 / Al 2 o 3 Must be above 30, otherwise it is difficult to obtain high crystallinity products

[0004] However, using the SiO given in the literature 2 / Al 2 o 3 Scope of synthesis of Beta zeolite molecular sieve, the feed ratio of silicon source and aluminum source in the raw material is relatively high, and the yield of solid product is low, which is extremely unfavorable for industrial scale production

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