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ZSM-5 catalyst and preparation method and application thereof

A technology of ZSM-5 and catalyst, which is applied in the field of ZSM-5 catalyst and its preparation, and can solve the problems of insufficient acid modification of the outer surface and the decrease of the effective specific surface area of ​​the catalyst, etc.

Pending Publication Date: 2021-05-28
WISON ENG
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The preparation method of the present invention has a simple process, and the prepared ZSM-5 catalyst has good crystallization, and does not need to be loaded with too much silicon ester to cause pore blockage. At the same time, the binder is converted into a molecular sieve, and the effective specific surface area is improved, which better solves the problem caused by the introduction of the binder. The problem of the decrease of the effective specific surface area of ​​the catalyst and the insufficient acidic modification of the outer surface has obvious advantages in the shape-selective catalytic reaction, especially in the field of toluene shape-selective disproportionation reaction and toluene-methanol alkylation to p-xylene, which have great potential for industrial application

Method used

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  • ZSM-5 catalyst and preparation method and application thereof
  • ZSM-5 catalyst and preparation method and application thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0042] Weigh the molar ratio of SiO 2 / Al 2 o 3100 grams of ZSM-5 molecular sieve with a size of 300 nanometers and 37 grams of silica sol with a mass fraction of 30% were evenly mixed, extruded and formed, and after drying, they were roasted at a high temperature of 550 ° C for 4 hours to obtain sample A; 8 grams of 25 % tetrapropylammonium hydroxide aqueous solution, 1 gram of ammonium fluoride, and 40 grams of water were mixed evenly, and 10 grams of sample A was placed in the solution, hydrothermally crystallized at 170°C for 24 hours, washed and dried, and then calcined at 550°C for 4 hours , to obtain sample B; weigh 5 grams of sample B and place it in a reaction kettle, add 4 ml of 1.0 mole per liter tetraethyl orthosilicate cyclohexane solution, react at 170°C for 24 hours for chemical vapor deposition, take it out and dry it Calcined at 550° C. for 4 hours to obtain the binderless ZSM-5 catalyst A1 that removes the acidity of the outer surface.

[0043] figure 1 I...

Embodiment 2

[0045] Weigh the molar ratio of SiO 2 / Al 2 o 3 Mix 100 grams of ZSM-5 molecular sieve with a size of 300 nanometers and 25 grams of white carbon black evenly, extrude into a rod, dry it and roast it at 550°C for 4 hours to obtain sample A; add 5 grams of tetrapropyl bromide to the reaction kettle Ammonium, 0.05 g of ammonium nitrate, and 10 g of water were mixed evenly, and 10 g of sample A was placed in the solution, hydrothermally crystallized at 160°C for 48 hours, washed and dried, and then roasted at 550°C for 4 hours to obtain sample B; weighed 5 g Sample B was placed in a reaction kettle, and 6 ml of 0.1 mole per liter tetramethyl orthosilicate cyclohexane solution was added, reacted at 160°C for 48 hours for chemical vapor deposition, taken out and dried at 550°C for 4 hours, and obtained Surface acidic binderless ZSM-5 catalyst A2.

Embodiment 3

[0047] Weigh the molar ratio of SiO 2 / Al 2 o 3 Mix 100 grams of ZSM-5 molecular sieve with a size of 450 and 300 nanometers and 5.3 grams of white carbon black evenly, extrude into a rod, dry and roast at 550 ° C for 4 hours to obtain sample A; add 0.1 grams of tetrapropyl bromide to the reaction kettle Ammonium, 2 grams of ammonium carbonate, and 100 grams of water were mixed evenly, and 10 grams of sample A was placed in the solution, hydrothermally crystallized at 180°C for 3 hours, washed and dried at 550°C for 4 hours to obtain sample B; weighed 5 grams Sample B was placed in a reaction kettle, and 3 ml of cyclohexane solution of 2.0 moles per liter of tetraethyl orthosilicate was added, and reacted at 180°C for 3 hours for chemical vapor deposition. After taking out and drying, it was roasted at 550°C for 4 hours to obtain Surface acidic binderless ZSM-5 catalyst A3.

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Abstract

The invention provides a ZSM-5 catalyst and a preparation method and application thereof. The preparation method comprises the following steps: 1) mixing a ZSM-5 molecular sieve and a binder silicon dioxide, molding, drying and roasting; (2) carrying out hydrothermal crystallization on the catalyst obtained in the step (1) in an aqueous solution containing a template agent quaternary ammonium salt and an additive, washing, drying and roasting; and 3) carrying out chemical vapor deposition on the catalyst obtained in the step 2) and a cyclohexane solution containing estersil, and roasting to obtain the ZSM-5 catalyst. The preparation method disclosed by the invention is simple in process, the prepared ZSM-5 catalyst is good in crystallization, the problems that the effective specific surface area of the catalyst is reduced and the acid modification of the outer surface is insufficient due to the introduction of a binder are well solved, and the ZSM-5 catalyst has obvious advantages in shape-selective catalytic reaction; especially, toluene and methanol alkylation has great industrial application potential in the field of p-xylene preparation.

Description

technical field [0001] The invention relates to the field of preparation of molecular sieves, in particular to a ZSM-5 catalyst and its preparation method and application. Background technique [0002] ZSM-5 molecular sieve has a two-dimensional ten-membered ring channel, one of which is a ten-membered ring straight channel, and the other is a ten-membered ring channel with a Zigzag shape: the channel structure is 0.51 nanometers × 0.55 nanometers ([100] direction) and 0.53 nanometers ×0.56 nm ([010] direction). It is widely used in shape-selective reactions such as toluene disproportionation to p-xylene and toluene methanol alkylation to p-xylene. Due to the pore size, the molecular dynamic diameter of p-xylene in xylene is smaller, which can diffuse out of the pore more easily. The diffused p-xylene is isomerized under the acidic action of the outer surface to form m-xylene and o-xylene, which reduces the selectivity of the target product p-xylene. Therefore, eliminatin...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B01J29/40C07C2/86C07C15/08
CPCB01J29/40B01J29/005C07C2/864B01J2229/32C07C2529/40C07C15/08Y02P20/52
Inventor 李猛杨文书
Owner WISON ENG