Selective Grafting of Ga(i-Bu)3 on the Silanols of Mesoporous H-ZSM-5 by Surface Organometallic Chemistry

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• 作者：Kai C. Szeto ; Alessandro Gallo ; Selene Hern谩ndez-Morejudo ; Unni Olsbye ; Aimery De Mallmann ; Fr茅d茅ric Lefebvre ; R茅gis M. Gauvin ; Laurent Delevoye ; Susannah L. Scott ; Mostafa Taoufik
• 刊名：Journal of Physical Chemistry C
• 出版年：2015
• 出版时间：November 25, 2015
• 年：2015
• 卷：119
• 期：47
• 页码：26611-26619
• 全文大小：441K
• ISSN：1932-7455

文摘

The reaction of triisobutylgallium toward meso-H-ZSM-5₂₅₀, prepared by desilication of H-ZSM-5, has been studied by IR, high field solid-state NMR, and EXAFS spectroscopies as well as elemental analysis. Grafting occurs selectively on silanol groups, resulting in the monopodal gallium species [(鈮iO)Ga(i-Bu)₂]. Since the Br酶nsted acidic protons remain largely unreacted, control of the surface organometallic chemistry affords a zeolitic material with both gallium sites and significant Br酶nsted acidity. The resulting bifunctional Ga(i-Bu)₃/meso-H-ZSM-5₂₅₀ shows higher activity and selectivity in propane aromatization than monofunctional meso-H-ZSM-5₂₅₀. The aromatic products arise from alkane dehydrogenation on the gallium sites, followed by oligomerization, cyclization, and aromatization of the resulting olefins on the Br酶nsted acid sites.