Preparations of SAPO-11 molecular sieve and SAPO-11 molecular sieve based catalyst

Abstract

The invention provides a method for preparing a large-aperture SAPO-11 molecular sieve, which comprises the following steps: adding an alcoholic solvent corresponding to an organic silicon source in a colloid admixture for crystallization and particularly adopting an admixture of dinpropylamine and long chain organic amine as a composite template agent simultaneously, thereby obtaining the large-aperture SAPO-11 molecular sieve through restraining the hydrolyzation of the organic silicon source and adjusting the molecule dimension of the template agent; and the large-aperture SAPO-11 molecular sieve can be used for the isomerization of a double-branch chain of hydrocarbons by a load active component. The invention further provides a preparation method for a catalyst adopting the obtained large-aperture SAPO-11 molecular sieve as a carrier; platinum family noble metals are loaded by using the SAPO-11 molecular sieve; and the prepared catalyst is used in the method for catalyzing the hydroisomerization reaction of matters of hydrocarbons; and meanwhile, the yield of isomers and the selectivity of the double-branch chain in a reaction product are improved.

Description

Technical field [0001] The invention relates to a preparation method of silicoaluminophosphate molecular sieve and related catalysts, in particular to a preparation method of SAPO-11 molecular sieve with large aperture and SAPO-11 molecular sieve-based catalyst. Background technique [0002] The isomerization of alkanes is an important reaction in petrochemical industry. The isomerization of linear alkanes into branched alkanes has a wide range of applications in improving the octane number of gasoline. However, in the isomerization process of straight-chain alkanes, because single-branched isomers are unfavorable for obtaining high octane number, how to make straight-chain alkanes double-branched or even multi-branched isomers is important for improving FCC The octane rating of gasoline is particularly important. [0003] The early alkane isomerization catalysts were liquid acid catalysts. Although this type of catalyst has high isomerization activity, its selectivity is poor, th...

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Problems solved by technology

[0006] Chinese patent CN02116279.4 (CN1448336A) discloses a synthesis method of a silicoaluminophosphate molecular sieve with an AFO structure, especially SAPO-41, the key of which is the control of the process of roasting and removing the template agent, and the obtained molecular sieve is loaded with noble metal Pt or Pd When used as a hydroisomerization reaction in the future, compared with the catalyst prepared by the molecular sieve obtained in the prior art, its isomerization selectivity and isomerization product yield are obviously improved, but for the catalyst double branched chain isomerization selectivity Sex issues are also not explained in the patent

The problem with these conventional synthetic methods is that the process of synthesizing SAPO-11 is not easy to repeat, or it is easy to form more Si regions and reduce the catalytic performance, which is not conducive to application.

[0009] Chinese patent 02136301.3 (notification number CN1155519C) discloses a method for synthesizing SAPO-11 molecular sieves in view of the shortcomings of conventional hydrothermal synthesis that are not easy to repeat

The SAPO-11 molecular sieve with conventional pore structure can be prepared as described in the above patents, but when it is applied to alkane hydroisomerization, most of the obtained isomers are single-branched isomers. The reason is mainly that conventional SAPO-11 The pore size of 11 molecular sieves is comparable to the size of the single branched chain isomer, and the size of the pore size limits the further isomerization of the single branched chain isomer

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