Surface aluminum-rich molecular sieve, preparation method and application, isomerization reaction catalyst and application thereof

A molecular sieve and isomerization technology, applied in the field of molecular sieves, can solve the problem that high activity and high isomer selectivity cannot be obtained at the same time, and achieve the effects of avoiding adverse effects, good application prospects, and high isomer selectivity

Active Publication Date: 2022-07-26
CHNA ENERGY INVESTMENT CORP LTD +1
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  • Abstract
  • Description
  • Claims
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Problems solved by technology

[0008] The purpose of the present invention is to provide a surface aluminum-rich molecular sieve and its preparation method and application and isomerization in order to overcome the problem that high activity and high isomerization selectivity cannot be obtained at the same time when molecular sieves in the prior art are used for isomerization conversion of long-chain alkanes Reaction catalyst and its application

Method used

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  • Surface aluminum-rich molecular sieve, preparation method and application, isomerization reaction catalyst and application thereof
  • Surface aluminum-rich molecular sieve, preparation method and application, isomerization reaction catalyst and application thereof
  • Surface aluminum-rich molecular sieve, preparation method and application, isomerization reaction catalyst and application thereof

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preparation example Construction

[0022] The present invention provides a first aspect of the present invention provides a method for preparing a surface aluminum-rich molecular sieve, the method comprising:

[0023] (1) Precursor gels A and B are prepared, the silicon-alumina ratio of the precursor gel A is 40-100, and the silicon-aluminum ratio of the precursor gel B is 100-400, and the silicon-alumina ratios of the two are different;

[0024] (2) respectively carrying out the first step of crystallization of the precursor gels A and B;

[0025] (3) The first-step crystallization products obtained from the precursor gels A and B, respectively, are mixed in a mass ratio of 1:(3-50) to carry out the second-step crystallization, and finally the surface aluminum-rich molecular sieve is obtained.

[0026] Herein, the silicon-alumina ratio refers to the molar ratio of silicon oxide to aluminum oxide.

[0027] In the present invention, the silicon-alumina ratio of the precursor gel A may be 40, 45, 50, 55, 60, 65,...

Embodiment approach

[0043] According to an embodiment, the ZSM-48 molecular sieve prepared by the method, the overall silicon-alumina ratio of the molecular sieve is 150-300, and the silicon-alumina ratio within 50 nm of the particle surface of the molecular sieve is 40-150, preferably 40-90. Here, the "within 50 nm thickness of the particle surface" should be understood as a thickness range of 50 nm from the particle surface.

[0044] According to an embodiment, the specific surface area of ​​the molecular sieve prepared by the method is not less than 200m 2 / g, preferably 200-1000m 2 / g; pore size is 0.53-0.56nm; pore volume is not less than 0.1cm 3 / g, preferably 0.1-1cm 3 / g.

[0045] In the present invention, the molecular sieve prepared by the method has high crystallinity, and the crystallinity is more than 98%.

[0046] The third aspect of the present invention provides the application of the molecular sieve described in the second aspect of the present invention in a catalytic react...

Embodiment 1

[0053] (1) 7.78g of hexamethylammonium bromide, 3.28g of sodium metaaluminate, 6g of sodium hydroxide were dissolved in 540g of water to form a solution; 200g of silica sol (concentration of 30wt%) was slowly stirred under stirring Slowly add to the solution of the above system, and stir evenly to prepare molecular sieve precursor gel A, in which SiO 2 : Al 2 O 3 :H 2 O: OH - : The molar ratio in terms of hexamethylammonium bromide is 1:0.02:30:0.15:0.0215;

[0054] (2) 6.34g of hexamethylammonium bromide, 0.82g of sodium metaaluminate, 5.2g of sodium hydroxide were dissolved in 270g of water to form a solution; 200g of silica sol (concentration of 30wt%) was stirred under stirring Slowly add it into the solution of the above system, and stir it evenly to prepare molecular sieve precursor gel B, in which SiO 2 : Al 2 O 3 :H 2 O: OH - : The molar ratio of hexamethylammonium bromide is 1:0.005:15:0.13:0.0175;

[0055] (3) Put the molecular sieve precursor gels A and B ...

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Abstract

The invention relates to the field of molecular sieves, and discloses a method for preparing a surface aluminum-rich molecular sieve. The method prepares two molecular sieve precursor gels with different silicon-alumina ratios, and controls the crystallization conditions so that the two molecular sieve precursor gels are respectively subjected to the first step of crystallization. and mixing the first-step crystallization products according to a predetermined ratio to carry out the second-step crystallization to finally obtain a surface aluminum-rich molecular sieve. The obtained molecular sieve not only has high crystallinity, but also has effective acid centers concentrated on the outer surface, showing high catalytic activity and high catalytic selectivity in the isomerization catalytic reaction of long-chain alkanes.

Description

technical field [0001] The invention relates to the field of molecular sieves, in particular to a surface aluminum-rich molecular sieve, a preparation method and application, an isomerization reaction catalyst and application thereof. Background technique [0002] Molecular sieves are often used as catalysts or catalyst carriers due to their pore structure. Among them, ZSM-5, ZSM-12, ZSM-22, ZSM-23, ZSM-48 and SSZ-32 molecular sieves are used more frequently. ZSM-48 is a kind of high-silica zeolite, which belongs to the orthorhombic structure. It has 10-membered pore openings without interlaced linear channels. The pores are connected by 5-membered rings, and the pore diameter is 0.53nm×0.56nm. Generally, pure silica ZSM-48 molecular sieve has good selectivity of light olefins in the reaction of synthesis gas to olefins, and the low silicon to aluminum ratio (SiO 2 / Al 2 O 3 ) ZSM-48 molecular sieve has good catalytic performance for isomeric cracking. [0003] "Synthes...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): B01J29/70B01J35/10C07C5/27C07C9/16
CPCB01J29/703B01J37/0018B01J35/1019B01J35/1023B01J35/1057C07C5/2775C07C5/2737B01J2229/18C07C9/16
Inventor 李景赵效洪朱加清艾军李浩
Owner CHNA ENERGY INVESTMENT CORP LTD
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