Characterization of Acidity and Porosity of Zeolite Catalysts by the Equilibrated Thermodesorption of n-Hexane and n-Nonane

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• 作者：Wac?aw Makowski ; Barbara Gil and Dorota Majda
• 关键词：Thermodesorption ; Zeolites ; n ; Hexane ; n ; Nonane ; Pore volume ; Acidity
• 刊名：Catalysis Letters
• 出版年：2008
• 出版时间：January, 2008
• 年：2008
• 卷：120
• 期：1-2
• 页码：154-160
• 全文大小：389.9 KB

文摘

Thermodesorption of n-hexane and n-nonane from the acidic and non-acidic zeolites ZSM-5 and Y was studied by means of the thermogravimetric temperature programmed equilibrated desorption (TPED) and quasi-equilibrated temperature programmed desorption and adsorption (QE-TPDA). Micropore volumes determined from the adsorption capacity of n-hexane were close to those determined by N₂ adsorption. Content and strength of acid sites in the acidic zeolites estimated by fitting the Arrhenius equation to the high temperature parts of QE-TPDA profiles of n-hexane attributed to its cracking were in agreement with their acidity characteristics obtained by IR spectroscopy of chemisorbed pyridine. The mesopore volume was determined from the QE-TPDA profiles of n-nonane. Coking observed only for QE-TPDA of n-nonane on H-USY zeolite resulted in blocking the micropores without affecting the mesopores.