NMR INVESTIGATIONS ON MOLECULAR TRANSPORT IN ZSM-5 TYPE ZEOLITES CONTAINING STRUCTURAL DEFECTS

被引：5

作者：

Kaerger, J. ^{[1
]}

Hunger, H. ^{[1
]}

Freude, D. ^{[1
]}

Pfeifer, H. ^{[1
]}

Caro, J. ^{[2
]}

Bulow, M. ^{[2
]}

Spindler, H. ^{[3
]}

机构：

[1] Karl Marx Univ, Sekt Phys, DDR-7010 Leipzig, Germany

[2] Akad Wissensch DDR, Zent Inst Phys Chem, DDR-1199 Berlin, Germany

[3] VEB Leuna Werke Walter Ulbricht, DDR-4220 Leuna, Germany

来源：

CATALYSIS TODAY | 1988年 / 3卷 / 05期

关键词：

D O I：

10.1016/0920-5861(88)87033-0

中图分类号：

O69 [应用化学];

学科分类号：

081704 ;

摘要：

NMR spectroscopy is used to study the transport properties in ZSM-5 type zeolites containing structural irregularities. Using methane as a probe molecule, the structural distortions in polycrystalline aggregates are found to lead to an enhanced molecular mobility. After coking, molecular mobility is more reduced than in the monocrystalline specimen. This finding is explained by a preferential coke deposition in the secondary pore system. A variation of the concentration of non-acidic OH groups (silanol groups) indicating non-intact Si-O-Si bonds as structural defects of the pentasil structure, leads to characteristic changes in the sorption and diffusion properties of water. Bronsted acid sites are probed by methane self-diffusion measurements after chemisorption of ammonia and pyridine.

引用

页码：493 / 499

页数：7

共 11 条

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