Rare earth-containing Al-ITQ-13 zeolite and synthesis method thereof

Abstract

The invention provides rare earth-containing Al-ITQ-13 zeolite and a synthesis method thereof. The rare earth-containing Al-ITQ-13 zeolite has a mole ratio of RE2O3 to SiO2 of 0.0005-0.1 and a mole ratio of SiO2 to Al2O3 of 10-2000. The synthesis method comprises the following steps of mixing a rare earth source, germanium oxide, a silicon source and water by stirring, adjusting a pH value, carrying out stirring, adding R(OH)2 into the mixture to obtain A, adding an aluminum source and a fluorine source into distilled water to obtain B, mixing the A and the B, adding crystal seeds into the mixture, carrying out stirring to obtain a gel mixture, and carrying out crystallization to obtain the rare earth-containing Al-ITQ-13 zeolite. The rare earth-containing Al-ITQ-13 zeolite has good hydro-thermal stability, high catalytic cracking activity, good product distribution and good alkene selectivity. The synthesis method has the advantages of good repeatability, rare earth content adjustability, easy penetration of aluminum into a molecular sieve skeleton, high aluminum source utilization rate and silica-alumina ratio adjustability.

Description

technical field [0001] The invention provides a rare earth-containing Al-ITQ-13 zeolite and a synthesis method thereof. Background technique [0002] ITQ-13 molecular sieve (USP6471941) is a new type of microporous material invented by Mobil in 2002 with a three-dimensional orthogonal interconnected channel structure with both 9-membered and 10-membered rings. The 9-membered ring channels are parallel to the a-axis and are straight channel, with an opening size of 0.40nm×0.49nm; the other two sets of 10-membered ring channels are straight channels (0.47nm×0.51nm) parallel to the b-axis and sinusoidal zigzag channels (0.48nm×0.51nm) roughly parallel to the c-axis 0.57nm). Since the pore structure of ITQ-13 is similar to that of ZSM-5 molecular sieve, and the average pore size is smaller, it will produce a unique shape-selective effect in the catalytic cracking process, especially the selectivity of propylene can be significantly improved. In addition, ITQ-13 molecular sieve...

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Problems solved by technology

The process of isomorphic substitution is cumbersome, part of the wafers in the product are broken, the proportion of non-framework aluminum is large, and the thermal stability is poor

[0005] In 2006, R.Castaneda et al. (J.Catal.2006,238,79~87) reported a method for directly synthesizing silicon-aluminum ITQ-13, but the silicon and aluminum sources were limited to ethyl orthosilicate and isopropyl Alcohol aluminum (Aluminum Isopropoxide, AlP), used templating agent is very expensive, simultaneously, the amount of water that requires in the synthesis system is less (H 2 O / SiO 2 The molar ratio is generally less than 10), and the hydrolysis process inevitably loses water, so the formed colloid is relatively viscous, and it is not easy to stir evenly, resulting in poor repeatability of the synthesis process

[0010] According to the above, ITQ-13 molecular sieve also shows good catalytic performance in aromatization, isomerization, toluene disproportionation, alkylation, lubricating oil dewaxing, lubricating oil modification and other reactions, and has shown important The industrial application value of Al-ITQ-13 containing rare earth, especially the Al-ITQ-13 containing rare earth in the framework will most likely show better performance than ITQ-13, but there is no Al-ITQ-13 containing rare earth at present. According to any patents and literature reports on 13 zeolite molecular sieves, it is also difficult to effectively synthesize Al-ITQ-13 containing rare earths according to the teachings of the prior art, so it is of great practical significance to develop a method for effectively synthesizing rare earths

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