Heteropolyacids anchored on amino-functionalized MCM-41 and SBA-15 and its application to the ethanol conversion reaction

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• 作者：Alexandru Popa ; Viorel Sasca ; Orsina Verdes…
• 关键词：Heteropolyacids ; Mesoporous sieves ; 3 ; aminopropyl ; triethoxysilane ; Ethanol conversion ; Acetaldehyde
• 刊名：Journal of Thermal Analysis and Calorimetry
• 出版年：2017
• 出版时间：January 2017
• 年：2017
• 卷：127
• 期：1
• 页码：319-334
• 全文大小：
• 刊物类别：Chemistry and Materials Science
• 刊物主题：Physical Chemistry; Analytical Chemistry; Polymer Sciences; Inorganic Chemistry; Measurement Science and Instrumentation;
• 出版者：Springer Netherlands
• ISSN：1588-2926
• 卷排序：127

文摘

A series of heteropolyacids (HPA)–silica composites were prepared from H₃PMo₁₂O₄₀ (HPM) and H₄PVMo₁₁O₄₀ (HPVM) by chemically anchoring to the amine-functionalized mesoporous MCM-41 and SBA-15. These composites were characterized by FT-IR, XRD, N₂ adsorption, SEM, and TEM for their structural integrity and physicochemical properties. The effect of the support on thermal stability was investigated by TG–DTG and DTA. The evolved gases during the thermal analysis of prepared composites were identified by online mass spectrometry coupled with TG technique. It was evidenced that HPAs species were finely dispersed on amine-functionalized molecular sieves via chemical immobilization and the structure of the HPAs is preserved over mesoporous materials. From thermal analysis of HPA–silica composites was observed an important mass loss above 553 K which is due to the decomposition of amino propyl functional group. For this reason prepared composites can be utilized as dispersed catalysts for the reactions performed below 553 K. Catalytic properties of these composites were studied by using ethanol conversion at different temperatures. The HPA supported on molecular sieves exhibited an enhanced oxidation catalytic activity (formation of acetaldehyde) and a lower acid catalytic activity (formation of ethylene and diethyl ether) compared to the parent catalysts. The favorable effect of HPAs deposition on silica supports for oxidehydrogenation pathway to acetaldehyde results from the examination of and reaction rate values. For all reaction temperatures, the reaction rates of acetaldehyde formation are higher for supported samples than unsupported ones.