Method for preparing submicron all-silicon DD3R molecular sieve

A molecular sieve and sub-micron technology, applied in the chemical industry, can solve the problems of long synthesis time, cumbersome process and high cost, and achieve the effect of shortening the synthesis period, uniform crystal size and increasing the crystallization rate.

Inactive Publication Date: 2015-11-04
SHANGHAI ADVANCED RES INST CHINESE ACADEMY OF SCI +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] The purpose of the present invention is to overcome the defects of the prior art and provide a method for rapidly synthesizing submicron-level all-silicon DD3R molecular sieves, which overcome

Method used

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  • Method for preparing submicron all-silicon DD3R molecular sieve

Examples

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Embodiment 1

[0039] In this embodiment, 0.046wt% seed crystals are added, the molar ratio of water to silicon in the silicon source is 100, and all-silicon DD3R molecular sieves are synthesized by microwave at 160° C. for 12 hours.

[0040] After mixing 1.68 g of tetraethylammonium hydroxide with 1.51 g of amantadine, add 33.1 g of H 2 O stirred for about 0.5 hour, then slowly added dropwise 3 gram of silica sol, SiO in the silica sol 2 The content of DD3R was 40wt%. After stirring for 24 hours, 20 mg of all-silicon DD3R seed crystals were added, stirred for 5 minutes, and then heated by microwave at 160° C. for 12 hours. After the product is taken out, it is washed with deionized water, centrifuged, and dried to obtain all-silicon DD3R molecular sieve crystals.

[0041] figure 1 It is a scanning electron microscope photograph of the all-silicon DD3R molecular sieve crystal in this example, the all-silicon DD3R molecular sieve crystal is a rhombohedral crystal of about 1 micron, the crys...

Embodiment 2

[0044] In this example, 0.046wt% seed crystals were added, the molar ratio of water to silicon in the silicon source was 50, and the all-silicon DD3R molecular sieve was synthesized by microwave at 160° C. for 12 hours.

[0045] The difference from Example 1 is that the molar ratio of water to silicon in the silicon source is 50, and the rest of the steps and parameters are the same as in Example 1.

[0046] image 3 This is the scanning electron microscope photo of the all-silicon DD3R molecular sieve crystal obtained in this example. The all-silicon DD3R molecular sieve crystal is a rhombohedral crystal of about 0.7 microns, the crystal size is relatively uniform, and the yield is >80%.

[0047] Figure 4 It is the XRD spectrum of the all-silicon DD3R molecular sieve crystal obtained in this example, which is consistent with the standard spectrum.

Embodiment 3

[0049] In this example, 0.046wt% seed crystals were added, the molar ratio of water to silicon in the silicon source was 30, and the all-silicon DD3R molecular sieve was synthesized by microwave heating at 160° C. for 12 hours.

[0050] The difference from Example 1 is that the molar ratio of water to silicon in the silicon source is 30, and the rest of the steps and parameters are the same as in Example 1.

[0051] Figure 5 It is a scanning electron microscope photo of an all-silicon DD3R molecular sieve crystal. The all-silicon DD3R molecular sieve crystal is a rhombohedral crystal of about 0.4 microns, the crystal size is relatively uniform, and the yield is >80%. At the same time, the specific surface area measured by nitrogen adsorption is 256m 2 / g.

[0052] Figure 6 It is the XRD spectrum of the all-silicon DD3R molecular sieve crystal, which is consistent with the standard spectrum.

[0053] Figure 7 It is the nitrogen adsorption isotherm of the all-silicon DD3R m...

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Abstract

The present invention provides a method for preparing a submicron all-silicon DD3R molecular sieve. The method comprises the following steps: 1) mixing a silicon source, amantadine, water and an auxiliary template agent to obtain crystal synthesis mother liquor and stirring and ageing the crystal synthesis mother liquor; and 2) adding 0.01-5% by mass of seed crystals into the crystal synthesis mother liquor and heating the crystal synthesis mother liquor with the seed crystals at 120-220 DEG C, wherein the auxiliary template agent is one or more selected from the group consisting of tetramethyl ammonium hydroxide, tetraethyl ammonium hydroxide, tetraethyl ammonium fluoride, tetraethyl ammonium bromide, tetrabutyl ammonium hydroxide and tetrabutyl ammonium bromide. According to the present invention, by adopting the method of mixing the template agent and adding the seed crystals, an induction period in a crystallization process is greatly shortened, a crystallization rate is increased and a synthesis period of the DD3R molecular sieve is shortened, so that the synthesis period of the submicron all-silicon DD3R molecular sieve is shortened from 25 days in the prior art to 3 hours; and the prepared DD3R molecular sieve is uniform in crystal size, has a particle size less than 1 micrometer, has a yield rate close to 100%, and has great application potential in adsorption and separation fields.

Description

technical field [0001] The invention relates to the field of chemical engineering, and specifically discloses a method for preparing submicron all-silicon DD3R molecular sieves. Background technique [0002] Zeolite molecular sieves have the advantages of chemical stability, thermal stability, mechanical stability, uniform pore size and fast material transmission, and have been widely used in the field of gas adsorption and separation applications. The structural code of DD3R molecular sieve is DDR. This molecular sieve is a small-pore molecular sieve. The pore size of its eight-membered ring is 0.36×0.44nm, which is close to the dynamic diameter of a large number of common small molecule gases. Therefore, in CO 2 -CH 4 Separation and O 2 / N 2 It has great application prospects in the separation process. The all-silicon DD3R skeleton structure does not contain aluminum and is an all-Si skeleton structure, so it has strong hydrothermal stability, chemical stability, solve...

Claims

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Application Information

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IPC IPC(8): C01B37/02
Inventor 张建明李猛张延风林艳君刘琛胡登白璐曾高峰孙予罕肖亚宁刘斌王东飞
Owner SHANGHAI ADVANCED RES INST CHINESE ACADEMY OF SCI
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