On the acidic properties of conventional and novel zeolitic materials: A DFT investigation

COMP 51

Mohamed Elanany, mohamed.elanany@fundp.ac.be and Daniel P. Vercauteren. Department of Chemistry, PCI labo, University of Namur, 61 Rue de Bruxelles, Namur, 5000, Belgium
The acidic properties of zeolitic materials play an important role regarding their applications. Therefore, we carried out reliable density functional calculations to measure the relative acid sites strength of various zeolitic structures using the DMol3 program. Results show that: (a) MnIIAlPO4-34 possesses the strongest Brønsted acid sites in the investigated series, viz., CrII, FeII, MnII, CoII, and NiII; (b) In H-MOR structure, Brønsted acid sites in the main channels are stronger than acid sites in the side pockets; (c) The strength of acid sites in MIVAlPO4-5 (M= Si, Ti or Zr) has been correlated to the M-O-Al bond angle and decrease in the order SiAlPO4-5> TiAlPO4-5> ZrAlPO4-5. Finally, organic moieties, viz., CH2 or NH incorporation into the chabazite framework decreases the strength in the order: CHA> ZOL-CH2 > ZOL-NH. Extension to MFI structure and multi-dopant AlPOs will also be addressed.
 

Quantum Chemistry
1:30 PM-4:15 PM, Sunday, August 19, 2007 BCEC -- 162A, Oral

Division of Computers in Chemistry

The 234th ACS National Meeting, Boston, MA, August 19-23, 2007