On the Loewenstein rule and mechanism of zeolite dealumination

Autor:	A. G. Pelmenschikov, Georgii M. Zhidomirov, E. A. Paukshtis, M. O. Edisherashvili
Rok vydání:	1992
Předmět:	Physics Reaction mechanism Aluminosilicate Lattice (order) General Engineering Ab initio Physical chemistry Chemical interaction Physical and Theoretical Chemistry Molecular sieve Zeolite Chemical composition
Zdroj:	The Journal of Physical Chemistry. 96:7051-7055
ISSN:	1541-5740 0022-3654
DOI:	10.1021/j100196a039
Popis:	The reason for and the peculiarities of dealumination of aluminum-rich zeolites are explained on the basis of ab initio SCF MO calculations of the energies of local chemical interactions in the zeolite lattice. As distinct from Dempsey-Mikovsky-marshall electrostatic approach (DMM), a conclusion is made that simultaneous extraction of the most closely-situated structural elements from the lattice takes place. The first step of this reaction is their mutual extracoordination according to the scheme. This step and the subsequent formation of large nuclei of hydroxoaluminum phases are regarded as a transformation of the lattice into a most energetically favorable state corresponding to the chemical composition nSiO{sub 2}{center_dot}mAl{sub 2}O{sub 3}{center_dot}kH{sub 2}O. 33 refs., 1 fig., 2 tabs.
Databáze:	OpenAIRE
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