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Preparation of toluene shape-selective disproportionation without adhesive

A binder-free and catalyst-free technology, applied in physical/chemical process catalysts, molecular sieve catalysts, chemical instruments and methods, etc., can solve the problems of complicated operation process, difficult industrial application, long process time, etc., and achieve simple process, environmental protection, The effect of fewer modification times and easy availability of raw materials

Inactive Publication Date: 2008-09-10
NANJING UNIV OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

CN1290193A invented a modification method of converting binder silica into small-grain ZSM-5 and coating ZSM-5 zeolite. The conversion method is the same as CN1059424C, and the catalyst has shown good performance in toluene methylation reaction. activity, but the selectivity to p-xylene is still 24% of the thermodynamic equilibrium
[0004] Among the above binder-free shaped ZSM-5 zeolite catalysts, some are converted by solid-phase method, and the process takes a long time, and all of them are organic amine templates; some are prepared by the conversion method of silica binder without binder. In the zeolite catalyst, organic amines such as tetrapropylammonium bromide are also used as templates, and polysiloxane is used as a modifier. Only when the number of modifications reaches more than 4 times can it have a shape-selective catalytic effect. The amount of siloxane is relatively large; some use in-situ carbon precipitation technology to modify binderless zeolite, the operation process is complicated, and it is difficult for industrial application

Method used

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  • Preparation of toluene shape-selective disproportionation without adhesive
  • Preparation of toluene shape-selective disproportionation without adhesive
  • Preparation of toluene shape-selective disproportionation without adhesive

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0023] Take 80 parts by weight of ZSM-5 zeolite with a silicon-aluminum ratio of 38 and 20 parts of silica sol (calculated as silicon dioxide) and mix, then add 1 part of kale powder and water to knead and extrude into strips, dry it, Calcined at a high temperature of 550° C. for 3 hours to obtain a shaped catalyst with a length of 10 mm and a diameter of 2 mm. Put 10 g of shaped catalyst into 10 g of 60% ethanol-NaOH solution with a pH of 12, and crystallize at 190° C. for 48 h. Take out the solid sample after crystallization, wash to neutrality with deionized water, XRD result shows, the crystallinity of sample increases, and silica has been converted into the zeolite of MFI structure in above-mentioned hydrothermal system (see attached figure 1 ), with figure 2 and 3 The SEM results show that the binder after hydrothermal crystallization has been transformed into a zeolite with a small-grained MFI structure, and is well covered on the surface of the procatalyst.

Embodiment 2

[0025] Take 70 parts by weight of ZSM-5 zeolite with a silicon-aluminum ratio of 38 and 30 parts of white carbon black, add 2 parts of citric acid and an appropriate amount of water, knead and extrude it, dry it, and bake it at a high temperature of 600 ° C for 2 hours. A shaped catalyst with a length of 10 mm and a diameter of 2 mm was obtained. Put 10 g of the shaped catalyst into 20 g of 40% ethanol-KOH solution with a pH of 13, and crystallize at 160° C. for 120 h. The solid sample after crystallization was taken out, washed with deionization until neutral, and XRD characterization showed that the crystallinity of the sample increased, and the silica had been transformed into a zeolite with MFI structure.

Embodiment 3

[0027] Take 60 parts by weight of ZSM-5 zeolite with a silicon-aluminum ratio of 38, 39 parts of silica sol (calculated as silica), and 1 part of aluminum hydroxide sol (calculated as alumina) and mix them, and add 1 part of fiber It was kneaded and extruded by plain and appropriate amount of water, dried and calcined at 400°C for 8 hours to obtain a molded catalyst with a length of 10 mm and a diameter of 2 mm. Put 10 g of shaped catalyst into 20 g of 80% ethanol-NaOH solution with a pH of 13, and crystallize at 200° C. for 48 h. The solid sample after crystallization was taken out and washed with deionization to neutrality. The XRD characterization showed that the crystallinity of the sample increased, and the binder had been transformed into a zeolite with MFI structure.

[0028] Example 3

[0029] Get 70 parts by weight of ZSM-5 zeolite with a silicon-aluminum ratio of 38, 29.5 parts of silica sol (calculated as silicon dioxide), and 0.5 part of aluminum sulfate (calculat...

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Abstract

The invention relates to a preparation method for a binderless ZSM-5 zeolite catalyst used for shape-selective disproportionation of toluene. The preparation method mainly takes the ZSM-5 zeolite as the main active component and is prepared by a series of modifying methods of shaping, template-free hydrothermal crystallization, pickling, dealuminizing, siliceous reinforcing, and silicate ester chemical liquid phase sediment treatment. The content of the effective component, ZSM-5 zeolite, in the catalyst is high, the product has high crystallinity and relatively high mechanical strength; no organic amine template agents are adopted during the preparation process of the catalyst; the process is simple. The modified catalyst shows excellent catalytic activity and ultra-high selectivity to dimethyl benzene during the catalytic reaction of shape-selective disproportionation of toluene. The catalyst has simple preparation technique, lower cost and promising application prospect.

Description

technical field [0001] The invention belongs to the technical field of catalyst preparation, in particular to a method for preparing a binder-free ZSM-5 zeolite catalyst, in particular to a method for preparing a binder-free toluene shape-selective disproportionation catalyst. Background technique [0002] The ZSM-5 zeolite molecular sieve (USP 3702886) invented by Mobil Petroleum Company of the United States has become a very important shape-selective catalytic material with its unique pore structure and good catalytic performance. It has been used in toluene disproportionation, isomerization, alkylation, etc. It has been widely used in petrochemical process. [0003] ZSM-5 zeolite is used as an active component of industrial catalysts. Generally, 20%-60% of binders are added to zeolite powder to make catalyst particles with certain mechanical strength and shape. These binders are amorphous Substances do not have similar adsorption and catalytic properties to zeolite, and ...

Claims

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Application Information

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IPC IPC(8): B01J29/40C07C15/08
CPCY02P20/52
Inventor 王军任晓乾
Owner NANJING UNIV OF TECH
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