沸石
纳米晶材料
结晶
超临界流体
硅酸铝
催化作用
材料科学
微晶
成核
化学工程
无机化学
化学
结晶学
有机化学
纳米技术
工程类
作者
M. Lakshmi Kantam,B. Purna Chandra Rao,B. M. Choudary,K. Koteswara Rao,B. Sreedhar,Yasuhiro Iwasawa,Takehiko Sasaki
出处
期刊:Journal of Molecular Catalysis A-chemical
[Elsevier]
日期:2006-06-01
卷期号:252 (1-2): 76-84
被引量:26
标识
DOI:10.1016/j.molcata.2006.02.044
摘要
Nanocrystalline zeolite beta with Si/Al ratios 12.5–50 has been synthesized by applying a two-stage varying temperature synthesis and supercritical fluid aided crystallization. Low temperature nucleation of clear aluminosilicate gel and SCF aided crystallization gave quantitative yields of nanocrystalline zeolite beta in shorter crystallization time without the use of alkali cations and seeded gel. The obtained nanocrystalline zeolite beta catalysts are thoroughly characterized by X-ray diffraction, N2 adsorption, 29Si and 27Al MAS NMR, IR spectroscopy and Al incorporation in framework was studied by XPS. These nanocrystalline zeolite beta catalysts displayed good activity and high selectivity towards 4-nitro-o-xylene in the nitration of o-xylene when compared to microcrystalline zeolite beta.
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