Method for preparing titanium-silicalite molecular sieve from natural zeolite through supercritical replacement and modification

A titanium-silicon molecular sieve and supercritical replacement technology, which is applied in the production of crystalline aluminosilicate zeolites and bulk chemicals, can solve the problems of difficult preparation of titanium-silicon molecular sieves with high titanium content, high gas-solid phase mass transfer resistance, and natural zeolites. Low purity and other problems, to achieve the effect of low production cost, eliminate mass transfer resistance, and increase added value

Inactive Publication Date: 2011-06-22
ZHEJIANG UNIV
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  • Abstract
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  • Application Information

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Problems solved by technology

However, the disadvantage of this method is that the reaction temperature is high, and the skeleton of the zeolite molecular sieve will inevitably undergo partial thermal collapse. In addition, due to the low purity of natural zeolite, the pores are not regular, twisted and blocked, so the mass transfer resistance of the gas-solid phase is relatively large. , it is difficult to prepare titanium-silicon molecular sieves with high titanium content

Method used

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  • Method for preparing titanium-silicalite molecular sieve from natural zeolite through supercritical replacement and modification
  • Method for preparing titanium-silicalite molecular sieve from natural zeolite through supercritical replacement and modification

Examples

Experimental program
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Effect test

Embodiment 1

[0023] (1) Put 30g of natural mordenite in a 500ml three-path bottle, add 150ml, 0.8M NH 4 The Cl solution was stirred at 80°C for 2 hours, washed with water, dried, and repeated twice;

[0024] (2) Take 10g of natural mordenite treated by (1) in a 500ml three-path bottle, add 200ml6MH 2 SO 4 The solution was stirred at 70°C for 0.5h, washed with water, and baked at 105°C for 10 hours;

[0025] (3) In a 100ml autoclave, add 2g of the dealuminated zeolite treated in (2) into a stainless steel tray placed on the upper part of the autoclave, add n-butyl titanate with a Si / Ti of 120, and heat to 35°C. Pump titanium dioxide into the autoclave to a pressure of 7.5Mpa, react under this condition for 3 hours, slowly exhaust to room temperature, take out the sample, wash with absolute ethanol, dry at 105°C for 10 hours, and dry at 300°C in an air atmosphere Roast for 5 hours to obtain a titanium-containing molecular sieve sample; the sample is characterized by powder X-ray diffracti...

Embodiment 2

[0027] (1) Put 30g of natural mordenite in a 1000ml three-path bottle, add 600ml, 0.1M NH 4 NO 3 The solution was stirred at 70°C for 5 hours, washed with water, dried, and repeated 4 times;

[0028] (2) Take 20g of natural mordenite treated by (1) in a 500ml three-path bottle, add 100ml1MHNO 3 The solution was stirred at 85°C for 8h, washed with water, and baked at 105°C for 10 hours;

[0029] (3) In a 100ml stainless steel autoclave, add 60ml of absolute ethanol, place 2g of the sample treated in (2) in the stainless steel tray on the upper part of the autoclave, add isobutyl titanate with a Si / Ti of 10, The temperature was programmed to rise to 250°C, and the pressure of the autoclave was 10Mpa. Under these conditions, the reaction was carried out for 0.5 hours, and the heating was stopped. The temperature and pressure were slowly reduced to room temperature and normal pressure. The samples were taken out, washed with absolute ethanol, and dried at 105°C for 10 hours. Ca...

Embodiment 3

[0031] (1) Place 30g of natural mordenite in a 500ml three-path bottle, add 300ml, 1.0M (NH 4 ) 2 SO 4 The solution was stirred at 100°C for 1 hour, washed with water, dried, and repeated once;

[0032] (2) Take 20 g of natural clinoptilolite treated in (1) in a 500 ml three-path bottle, add 300 ml of 12M HCl solution, stir at 100° C. for 5 hours, wash with water, and bake at 105° C. for 10 hours;

[0033] (3) In a 100ml stainless steel autoclave, place 2g of the sample treated in (1) in the stainless steel tray on the upper part of the autoclave, add 60ml of n-hexane, add isopropyl titanate with a Si / Ti of 150, and program the temperature To 220°C, the pressure of the autoclave is 8Mpa. Under this condition, react for 6 hours, stop heating, and the temperature and pressure will slowly return to room temperature and normal pressure. Take out the sample, wash it with absolute ethanol, and dry it at 105°C for 10 hours. Calcined at 700°C for 5 hours in an air atmosphere to obt...

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Abstract

The invention relates to natural zeolite material modification, and aims to provide a method for preparing a titanium-silicalite molecular sieve from natural zeolite through supercritical replacement and modification. The method comprises the following steps of: performing ion exchange treatment on the natural zeolite, treating by using a chemical dealumination method, and performing supercritical replacement reaction, putting the zeolite subjected to chemical dealumination treatment on the upper part of an autoclave, and ensuring that the zeolite is not directly contacted with carbon dioxide or an organic solvent; regulating the pressure and temperature until the pressure and the temperature are higher than critical parameters of the carbon dioxide or the organic solvent for reaction, and after the reaction is finished, washing a sample by using the carbon dioxide or the organic solvent and drying; and roasting in the air to obtain the titanium-silicalite molecular sieve. By the method, the mass transfer resistance of a titanium source in micropores of the molecular sieve is greatly reduced, the prepared sample has the characteristics of high titanium content, uniform titanium distribution and the like, and the method is a new method for improving the additional value of the natural zeolite product. The heteroatom molecular sieve prepared by the method is low in production cost and easy to operate, and has wide market prospect when used as an industrial catalyst and environmentally functional material.

Description

technical field [0001] The invention belongs to the technical field of modification of natural zeolite materials, and in particular relates to a method for preparing titanium-silicon molecular sieves through supercritical displacement modification of natural zeolite. technical background [0002] As an important catalyst and adsorption material, zeolite has been widely used in petrochemical and chemical industries. In the early 1980s, in order to endow synthetic molecular sieves with special catalytic properties, people devoted themselves to the synthesis of heteroatom molecular sieves containing titanium, zirconium, chromium, gallium, etc. Or metal atoms, which can introduce and adjust the acidity, ion exchange and redox properties of molecular sieves. The successful synthesis of this type of heteroatom molecular sieves has expanded the field of molecular sieve catalysts from acid catalysis to selective oxidation catalysis. Important development milestone. [0003] The mo...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01B39/08
CPCY02P20/54
Inventor 肖丽萍周慧王卉郑小明
Owner ZHEJIANG UNIV
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