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Method for preparing toluene disproportionation zeolitic catalyst with increased para-selectivity

A technology of zeolite catalyst and toluene disproportionation, applied in physical/chemical process catalysts, molecular sieve catalysts, chemical instruments and methods, etc., can solve the problems of low conversion rate, expensive solvent used, cumbersome preparation process, etc., achieve good effect and low cost , the effect of simple process

Inactive Publication Date: 2008-10-29
NANJING TECH UNIV
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0014] The purpose of the present invention is: in order to overcome the cumbersome preparation process of the toluene selective disproportionation catalyst in the prior art, the price of the organosilicon modifier used is high, the structure is complex, or the amount is large, and the solvent used is expensive; or the catalyst needs to add precious metals and or Due to the disadvantages of low conversion rate, a preparation method is simple, the molding agent and modifier used are easy to obtain and cheap, the dosage is small, no in-situ shape-selective modification is required, and the catalyst has high activity, high para-selectivity and stability. Modification method for preparation of good toluene selective disproportionation catalyst

Method used

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  • Method for preparing toluene disproportionation zeolitic catalyst with increased para-selectivity
  • Method for preparing toluene disproportionation zeolitic catalyst with increased para-selectivity
  • Method for preparing toluene disproportionation zeolitic catalyst with increased para-selectivity

Examples

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Effect test

Embodiment 1

[0040] Embodiment 1 (comparative example)

[0041] In this example, the method of the present invention is used to modify the catalyst by chemical liquid deposition silicon.

[0042] The hydrogen type ZSM-5 zeolite powder (Nankai University Catalyst Factory) that the silicon-aluminum ratio is 38 is mixed with sheepsweet in a weight ratio of 80:20, and then the kale powder that is 4 weight parts is added therein, and fully mixed until Mix well, add 5 parts of water, knead and extrude.

[0043] The solid obtained by extruding was air-dried, dried at 110° C. for 3 hours, and calcined at 550° C. for 3 hours to obtain catalyst A.

[0044] The toluene disproportionation reaction is carried out on a high-pressure micro-reaction device. Take 1 gram of catalyst A and fill it in the middle section of a stainless steel reaction tube with a length of 500 mm and an internal diameter of 14 mm, and fill quartz sand up and down. Pure toluene feed, mass space velocity is 3.0h -1, the reacti...

Embodiment 2-5

[0054] The following examples examine the effect of deposition times on the para-selectivity of catalysts.

[0055] Take 10 grams of the above-mentioned molded catalyst A particles, add cyclohexane solvent at room temperature (20° C.) at a ratio of liquid-solid mass ratio of 8:1, then add 2 grams of tetraethyl orthosilicate, and carry out chemical liquid phase under stirring conditions. After deposition reaction for 10 hours, drying and aging at 110°C for 5 hours, the temperature was raised to 550°C in a muffle furnace at 2°C / min and calcined for 4 hours to obtain catalyst B.

[0056] Take 5 grams of catalyst B particles, and add 1 gram of tetraethyl orthosilicate under the same conditions for deposition, aging and roasting, and the obtained catalyst is C.

[0057] Take 5 grams of shaped catalyst A particles, according to the modification conditions of catalyst B, add 2 grams at a time for silicon modification, and obtain catalyst D. The catalyst of embodiment 2-5 carries out...

Embodiment 6-11

[0062] The following examples investigate the effects of different organic acid solutions on the active components of zeolite on catalyst activity and chemical liquid phase deposition of tetraethyl orthosilicate

[0063] Take 20 grams of catalyst A particles, add 160 grams of oxalic acid aqueous solution with a concentration of 2 mol / L, reflux and stir at 80 ° C for 2 hours, then filter, wash and dry to obtain catalyst E. Then take 15 grams of catalyst E, modify it with 2.25 grams of tetraethyl orthosilicate by the method described in the examples, and then obtain catalyst F through drying, aging and roasting.

[0064] Also take 10 grams of catalyst A particles, add 40 grams of citric acid aqueous ethanol solution with a concentration of 2 mol / L, reflux and stir at 80° C. for 2 hours, then filter, wash and dry to obtain catalyst G. Another 8 grams of catalyst G was taken, modified with 1.2 grams of tetraethyl orthosilicate by the method described in the examples, and then drie...

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Abstract

The invention relates to a preparation method for zeolite catalyst to enhance para-position selectivity for toluene disproportionation, which comprises: adding natural clay adhesive and assist-extrusion agent contained alumina and silicon dioxide into hydrogen-type zeolite powder to form, treating with organic acid; using ethyl silicate for chemical liquid-phase deposition modification to dried sample; baking, aging, baking, and treating with 100% water vapor. This product can improve selectivity obviously, can achieve 96.5wt% to xylene selectivity when the toluene conversion is 23wt%, and needs low cost.

Description

Technical field: [0001] The invention relates to a method for preparing a catalyst, in particular to a method for preparing a zeolite catalyst for increasing para-selective toluene shape-selective disproportionation. Background technique: [0002] Paraxylene (PX) is the main raw material for the production of purified terephthalic acid (PTA) in the polyester industry. Industrially, reformed gasoline, pyrolysis gasoline, toluene, C 9 C 8 Aromatics, but only xylenes with thermodynamic equilibrium composition (para: meta: ortho = 24%: 53%: 23%) can be obtained. , p-xylene must be obtained through adsorption separation or crystallization separation, and this separation process is complicated and consumes a lot of energy. [0003] Chang et al. pointed out in J.Amer.Chem.Soc.101(6783), 1979 that p-xylene could be selectively generated by using medium and microporous zeolites such as ZSM-5 zeolite for shape-selective disproportionation of toluene. ZSM-5 zeolite has a pore system...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): B01J29/40C07C5/27C07C15/08
CPCY02P20/52
Inventor 王军任晓乾梁金花李凯
Owner NANJING TECH UNIV
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