Structure of Framework Aluminum Lewis Sites and Perturbed Aluminum Atoms in Zeolites as Determined by 27Al{1H} REDOR (3Q) MAS NMR Spectroscopy and DFT/Molecular Mechanics

被引:99
作者
Brus, Jiri [1 ]
Kobera, Libor [1 ]
Schoefberger, Wolfgang [2 ]
Urbanova, Martina [1 ,3 ]
Klein, Petr [3 ]
Sazama, Petr [3 ]
Tabor, Edyta [3 ]
Sklenak, Stepan [3 ]
Fishchuk, Anna V. [3 ]
Dedecek, Jiri [3 ]
机构
[1] Acad Sci Czech Republic, Inst Macromol Chem, CR-16206 Prague 6, Czech Republic
[2] Univ Linz, A-4040 Linz, Austria
[3] Acad Sci Czech Republic, J Heyrovsky Inst Phys Chem, CR-18223 Prague 8, Czech Republic
关键词
aluminum; density functional calculations; Lewis acids; NMR spectroscopy; zeolites; ACID SITES; STATE; BETA; DEALUMINATION;
D O I
10.1002/anie.201409635
中图分类号
O6 [化学];
学科分类号
0703 ;
摘要
Zeolites are highly important heterogeneous catalysts. Besides BrOnsted SiOHAl acid sites, also framework Al-FR Lewis acid sites are often found in their H-forms. The formation of Al-FR Lewis sites in zeolites is a key issue regarding their selectivity in acid-catalyzed reactions. The local structures of Al-FR Lewis sites in dehydrated zeolites and their precursorsperturbed Al-FR atoms in hydrated zeoliteswere studied by high-resolution MAS NMR and FTIR spectroscopy and DFT/MM calculations. Perturbed framework Al atoms correspond to (SiO)(3)AlOH groups and are characterized by a broad Al-27 NMR resonance ((i)=59-62ppm, C-Q=5MHz, and =0.3-0.4) with a shoulder at 40ppm in the (27)AlMASNMR spectrum. Dehydroxylation of (SiO)(3)AlOH occurs at mild temperatures and leads to the formation of Al-FR Lewis sites tricoordinated to the zeolite framework. Al atoms of these (SiO)(3)Al Lewis sites exhibit an extremely broad (AlNMR)-Al-27 resonance ((i)approximate to 67ppm, C-Q approximate to 20MHz, and approximate to 0.1).
引用
收藏
页码:541 / 545
页数:5
相关论文
共 22 条
[1]   STUDY OF THE STATE OF ALUMINUM IN ZEOLITE-BETA [J].
BOURGEAT-LAMI, E ;
MASSIANI, P ;
DIRENZO, F ;
ESPIAU, P ;
FAJULA, F ;
COURIERES, TD .
APPLIED CATALYSIS, 1991, 72 (01) :139-152
[2]   Acid-catalyzed synthesis of mono- and dialkyl benzenes over zeolites:: Active sites, zeolite topology, and reaction mechanisms [J].
Cejka, J ;
Wichterlová, B .
CATALYSIS REVIEWS-SCIENCE AND ENGINEERING, 2002, 44 (03) :375-421
[3]   Investigation of the coordination state of aluminum in β zeolites by X-ray photoelectron spectroscopy [J].
Collignon, F ;
Jacobs, PA ;
Grobet, P ;
Poncelet, G .
JOURNAL OF PHYSICAL CHEMISTRY B, 2001, 105 (29) :6812-6816
[4]   Complex Analysis of the Aluminum Siting in the Framework of Silicon-Rich Zeolites. A Case Study on Ferrierites [J].
Dedecek, Jiri ;
Lucero, Melissa J. ;
Li, Chengbin ;
Gao, Fei ;
Klein, Petr ;
Urbanova, Martina ;
Tvaruzkova, Zdenka ;
Sazama, Petr ;
Sklenak, Stepan .
JOURNAL OF PHYSICAL CHEMISTRY C, 2011, 115 (22) :11056-11064
[5]   Effect of Al/Si Substitutions and Silanol Nests on the Local Geometry of Si and Al Framework Sites in Silicone-Rich Zeolites: A Combined High Resolution 27Al and 29Si NMR and Density Functional Theory/Molecular Mechanics Study [J].
Dedecek, Jiri ;
Sklenak, Stepan ;
Li, Chengbin ;
Gao, Fei ;
Brus, Jiri ;
Zhu, Qingjun ;
Tatsumi, Takashi .
JOURNAL OF PHYSICAL CHEMISTRY C, 2009, 113 (32) :14454-14466
[6]   MULTINUCLEAR SOLID-STATE NMR-STUDIES OF BRONSTED SITES IN ZEOLITES [J].
ERNST, H ;
FREUDE, D ;
WOLF, I .
CHEMICAL PHYSICS LETTERS, 1993, 212 (06) :588-596
[7]   SOLID-STATE NUCLEAR-MAGNETIC-RESONANCE STUDIES OF ACID SITES IN ZEOLITES [J].
FREUDE, D ;
ERNST, H ;
WOLF, I .
SOLID STATE NUCLEAR MAGNETIC RESONANCE, 1994, 3 (05) :271-286
[8]   ONE-DIMENSIONAL AND 2-DIMENSIONAL HIGH-RESOLUTION SOLID-STATE NMR-STUDIES OF ZEOLITE LATTICE STRUCTURES [J].
FYFE, CA ;
FENG, Y ;
GRONDEY, H ;
KOKOTAILO, GT ;
GIES, H .
CHEMICAL REVIEWS, 1991, 91 (07) :1525-1543
[9]   Formation of paramagnetic defect centers in aluminophosphate molecular sieves [J].
Hong, SB ;
Kim, SJ ;
Uh, YS .
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, 1996, 118 (34) :8102-8110
[10]   INVESTIGATION OF INTERNAL SILANOL GROUPS AS STRUCTURAL DEFECTS IN ZSM-5-TYPE ZEOLITES [J].
HUNGER, M ;
KARGER, J ;
PFEIFER, H ;
CARO, J ;
ZIBROWIUS, B ;
BULOW, M ;
MOSTOWICZ, R .
JOURNAL OF THE CHEMICAL SOCIETY-FARADAY TRANSACTIONS I, 1987, 83 :3459-&