SAPO-34 molecular sieve adjustable in micropore diameter and preparation method and application of SAPO-34 molecular sieve adjustable in micropore diameter

Abstract

The invention discloses an SAPO-34 molecular sieve adjustable in micropore diameter and a preparation method and application of the SAPO-34 molecular sieve adjustable in micropore diameter.The preparation method includes adding inert organic solvents into an SAPO-34 molecular sieve, adding easily-hydrolytic halide as a precipitant, and reacting for 2-10 hours prior to filtering, drying and roasting so as to obtain the SAPO-34 molecular sieve adjustable in micropore diameter.The SAPO-34 molecular sieve adjustable in micropore diameter is applied to MTO (methanol to olefins) for preparing low-carbon olefins from oxygen compounds by conversion.Compared with a silicon esterification deposition method and the like, an SAPO-34 micropore diameter adjusting method has the advantages of simplicity, low price, repeatability, reliability, wide applicable range, suitability for industrialization and the like.After adjustment by the SAPO-34 micropore diameter adjusting method, zeolite pore volume and inner surface properties are unchanged but orifice size is adjustable precisely, and accordingly the SAPO-34 molecular sieve demonstrates excellent shape selecting and separating properties for various organic matter mixture systems diverse in geometric dimension and close in polarity and can be used for separating and purifying organic chemical reagents.

Description

technical field [0001] The invention relates to a SAPO-34 molecular sieve and a preparation method thereof, in particular to a SAPO-34 molecular sieve with adjustable micropore diameter, a preparation method and an application thereof, and belongs to the technical field of catalyst preparation. Background technique [0002] Due to the discontinuity of zeolite pore size change, it cannot meet the separation requirements of organic systems with various geometric sizes and similar polarities, which requires adjustment of the existing zeolite pore size. The traditional pore size modulation methods include cation exchange method, oxide surface modification method, etc., but these methods have certain limitations because they change the pore volume and surface properties of the zeolite while changing the pore size. [0003] Japan's Niwa et al. (J.Chem.Soc., Chem.Commun., 1982, 819-820) used Si(OCH3)4 as a modifier to modify zeolite by chemical vapor deposition (CVD). Since the mo...

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Problems solved by technology

[0005] SAPO-34 molecular sieve is used to convert oxygenates, including methanol, ethanol, methyl ether, etc. Regulating the ratio of ethylene and propylene in the product

Although the current CLD method can adjust the pore size of zeolite, there is no report on the use of CLD method to control the surface pore size of SAPO-34 molecular sieve. How to choose a suitable precipitant and modifier can not affect the catalytic performance of SAPO-34 molecular sieve or even Improving its catalytic performance in the MTO reaction is a difficult research point

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