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15-P-06-A reactivity index study to choose the best template for zeolite synthesis
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1 5 - Modelling and Theoritical Studies A (Tuesday) 15-P-06 - A reactivity index study to choose the best template for zeolite synthesis A. Chatterjee and T. Iwasaki
Inorganic Materials Section, Tohoku National Industrial Research Institute, 4-2-1 Nigatake, Miyagino-ku, Sendai 983-8551, JAPAN. Email: [email protected], Fax.'81-22-236-6839 The activity of different representative templating molecules along with zeolite framework is investigated using a range of reactivity indexes using density functional theory (DFT). From the values of local softness and the charge on the hydrogen atom of the bridging hydroxyl, resulted from the presence of aluminum in the framework, it is observed that the acidities of the aluminum containing zeolite type model systems, are dependent on several characteristics which are of importance within the framework of hard and soft acids and bases (HSAB) principle. We investigated the local softness of the interacting templates, to compare their affinity with the zeolite framework cluster models. A priori rule is formulated to choose the best template for a particular zeolite (e.g. ZSM-5) synthesis.
15-P-07- Effects of ion-exchanged alkali metal cations On the photolysis of alkyl ketones included within ZSM-5 zeolite cavities: A study of ab-initio molecular orbital calculations H. Yamashita*, S. Takada, M. Nishimura, H. Bessho and M. Anpo*
Osaka Prefecture University, yamashita@chem, osakafu-u.ac.ip, Japan Effects of ion-exchanged alkali metal cations on the adsorption and the photolysis (Norrish type I and type II reactions) of 2-pentanone included within the alkali metal cation-exchanged ZSM-5 zeolite have been investigated by experimental and theoretical approaches. The yields of the photolysis decreased and the ratio of the type I/ type II reactions increased, respectively, by changing the ion-exchanged cations from Cs + to Li +. The observed IR spectra of the adsorbed ketones and the ab initio molecular orbital calculations of this host-guest system indicate that the type I and type II reactions proceed from the staggered and eclipsed conformations of 2-pentanone, respectively, and that the smaller cation has the stronger electrostatic interaction between ketone and promotes the type I reaction of ketone efficiently.
15-P-08 - Encapsulated guest atoms within the basic beta cage of sodalitic zeolite. A theoretical ab-initio study N.U. Zhanpeisov and M. Anpo
Department of Applied Chemistry, Osaka Prefecture University, 1-I Gakuen-cho, Osaka 5998531, Japan, nurbost,n@ok. chem. osakafu-u.ac.jp Ab-initio quantum chemical calculations at the HF/3-21G* level of theory were applied to consider the nature of the active sites of sodalite [3-cage of the LTA type zeolite and faujasite structures. Especially, the nature of sodium, potassium and silicon atoms encapsulated within the sodalitic [3-cage, and their structural and molecular parameters have been described. We have shown that up to four sodium and four potassium atoms as well as five silicon atoms could be encapsulated within the sodalite 13-cage. The unique properties of these nano-size materials relate directly to the encapsulated guest atom containing fragments stabilized within the sodalite [3-cage of the LTA type zeolite or faujasite structures.
1 5 - Modelling and Theoritical Studies A (Tuesday) 15-P-06 - A reactivity index study to choose the best template for zeolite synthesis A. Chatterjee and T. Iwasaki
Inorganic Materials Section, Tohoku National Industrial Research Institute, 4-2-1 Nigatake, Miyagino-ku, Sendai 983-8551, JAPAN. Email: [email protected], Fax.'81-22-236-6839 The activity of different representative templating molecules along with zeolite framework is investigated using a range of reactivity indexes using density functional theory (DFT). From the values of local softness and the charge on the hydrogen atom of the bridging hydroxyl, resulted from the presence of aluminum in the framework, it is observed that the acidities of the aluminum containing zeolite type model systems, are dependent on several characteristics which are of importance within the framework of hard and soft acids and bases (HSAB) principle. We investigated the local softness of the interacting templates, to compare their affinity with the zeolite framework cluster models. A priori rule is formulated to choose the best template for a particular zeolite (e.g. ZSM-5) synthesis.
15-P-07- Effects of ion-exchanged alkali metal cations On the photolysis of alkyl ketones included within ZSM-5 zeolite cavities: A study of ab-initio molecular orbital calculations H. Yamashita*, S. Takada, M. Nishimura, H. Bessho and M. Anpo*
Osaka Prefecture University, yamashita@chem, osakafu-u.ac.ip, Japan Effects of ion-exchanged alkali metal cations on the adsorption and the photolysis (Norrish type I and type II reactions) of 2-pentanone included within the alkali metal cation-exchanged ZSM-5 zeolite have been investigated by experimental and theoretical approaches. The yields of the photolysis decreased and the ratio of the type I/ type II reactions increased, respectively, by changing the ion-exchanged cations from Cs + to Li +. The observed IR spectra of the adsorbed ketones and the ab initio molecular orbital calculations of this host-guest system indicate that the type I and type II reactions proceed from the staggered and eclipsed conformations of 2-pentanone, respectively, and that the smaller cation has the stronger electrostatic interaction between ketone and promotes the type I reaction of ketone efficiently.
15-P-08 - Encapsulated guest atoms within the basic beta cage of sodalitic zeolite. A theoretical ab-initio study N.U. Zhanpeisov and M. Anpo
Department of Applied Chemistry, Osaka Prefecture University, 1-I Gakuen-cho, Osaka 5998531, Japan, nurbost,n@ok. chem. osakafu-u.ac.jp Ab-initio quantum chemical calculations at the HF/3-21G* level of theory were applied to consider the nature of the active sites of sodalite [3-cage of the LTA type zeolite and faujasite structures. Especially, the nature of sodium, potassium and silicon atoms encapsulated within the sodalitic [3-cage, and their structural and molecular parameters have been described. We have shown that up to four sodium and four potassium atoms as well as five silicon atoms could be encapsulated within the sodalite 13-cage. The unique properties of these nano-size materials relate directly to the encapsulated guest atom containing fragments stabilized within the sodalite [3-cage of the LTA type zeolite or faujasite structures.