Formation of MFI-type zeolite nanoparticles and zeolite-based suspensions

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• 作者：N. V. Kolesnichenko ; N. N. Ezhova ; O. V. Yashina
• 关键词：catalysis in dispersed phase ; catalysis on zeolites ; nanosized zeolites ; zeolite nanoparticles ; conversion of dimethyl ether ; lower olefins
• 刊名：Petroleum Chemistry
• 出版年：2016
• 出版时间：September 2016
• 年：2016
• 卷：56
• 期：9
• 页码：827-831
• 全文大小：
• 刊物类别：Chemistry and Materials Science
• 刊物主题：Industrial Chemistry/Chemical Engineering;
• 出版者：Pleiades Publishing
• ISSN：1555-6239
• 卷排序：56

文摘

Based on a commercial zeolite of the MFI type, nanoparticles have been produced using mechanical methods (grinding in a ball or planetary mill, classification by “stirring-up”) and ultrasonic treatment (UST) of zeolite in water. It has been found by spectral methods (XRD, DRIRS, 27Al and 29Si solid-state NMR) and adsorption analysis that the grinding of the zeolite leads to partial degradation of its structure and appearance of defects in the crystalline framework, whereas the zeolite crystal lattice remains completely intact after sonication in the aqueous medium. The sonication destroys MFI agglomerates to form nanoparticles down to 40–50 nm in size. The dispersion of the zeolite nanoparticles in silicone or hydrocarbon oil–(Syltherm 800 or Dowtherm RP, respectively) as a high-boiling-point liquid leads to the formation of ultrafine suspensions, the stability of which depends on the type of the dispersion medium. The nanosized zeolite suspensions are more stable in Dowtherm RP than in Syltherm 800: without agitation, they are persistent for at least 3 weeks (settling at room temperature).