含鋁中孔洞分子篩之結構鑑定與催化活性研究：直接合成與後修飾法之比較;Characterization and Catalytic Activity of Aluminum-containing Mesoporous Silica : A Comparative Study of Direct Synthesis and Post-synthesis methods

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题名:	含鋁中孔洞分子篩之結構鑑定與催化活性研究：直接合成與後修飾法之比較;Characterization and Catalytic Activity of Aluminum-containing Mesoporous Silica : A Comparative Study of Direct Synthesis and Post-synthesis methods
作者:	丁君強;Chun-Chiang Ting
贡献者:	化學研究所
关键词:	直接合成法;中孔洞分子篩;後修飾法;SBA-15;MCM-41;post-synthesis;direct-synthesis
日期:	2003-07-01
上传时间:	2009-09-22 10:10:36 (UTC+8)
出版者:	國立中央大學圖書館
摘要:	以(NH4)3AlF6 水溶液為試劑在pH 值為9.3的環境下在室溫中反應，藉由後合成法將鋁植入中孔洞分子篩 MCM-41 及 SBA-15 的骨架之中。同時也藉由直接合成法以 (NH4)3AlF6 為試劑將鋁植入中孔洞分子篩MCM-41的骨架之中研究植鋁後的結構及酸性活性的變化。在此篇研究中可以看到藉由直接合成法植鋁於中孔洞分子篩 MCM-41的結構中時，在低矽鋁比 (Si/Al = 2.5) 的條件下其仍能維持六角柱狀的結構排列並且有很強的布忍斯特酸酸性(Brǿnsted acid) 位置及不錯的酸性催化能力。植鋁後的中孔洞分子篩，可藉由 27Al MAS NMR 來觀測所植入的鋁在分子篩結構中的狀況，同時也以 ICP、XRD 及氮氣等溫吸/脫附儀來量測在所植入鋁含量不同的環境下的結構變化，並藉由酸性催化裂解cumene 的反應來探討植鋁後分子篩的酸性變化。在此研究中結合兩核種使用雙頻共振NMR的技術，如 1H {27Al}TRAPDOR MAS NMR 來探討藉由植鋁所產生的布忍斯特酸酸性位置的產生。並且可以看到不論是藉由直接合成法或是後修飾法將鋁植入中孔洞分子篩結構之中的含鋁觸媒分子篩，其表面積、孔洞體積以及孔洞直徑均會隨所植入的鋁含量增加而有遞減的趨勢。並且在低矽鋁比的條件下，不論是直接合成法或後修飾法所得到的含鋁中孔洞分子篩 (Al-MCM-41-2.5/MCM-41-Al-2.5/SBA-15Al-5)仍能維持其六角柱狀的結構排列。 Incorporation of aluminum into siliceous framework of MCM-41 and SBA-15 with post-synthesis method has been achieved by reacting mesoporous materials with an aqueous (NH4)3AlF6 solution at pH about 9.3 at room temperature. Aluminosilicate MCM-41 materials prepared by direct-synthesis alumination using (NH4)3AlF6 as the aluminum source exhibit remarkably high hexagonal structure order and possess stronger Brǿnsted acid sites compared to the parent materials. The states of Al in the Al-containing materials are analyzed by MAS NMR, the detailed properties of the materials under different aluminum content are characterized by ICP, XRD, N2 adsorption, and the catalytic cracking activity was tested in the cumene cracking reaction. Alumination generates Brǿnsted acid site which can be proved by 1H{27Al} TRAPDOR NMR, showing that well-developed Brǿnsted acid site at chemical shift of 3.9 ppm (SBA-15-Al-5, Si/Al = 32.8 by ICP). Irrespective of the preparation method, the surface area, pore volume and pore diameter of Al- containing mesoporous materials decrease with increasing Al content. The Al-MCM-41 (Si/Al = 2.5 in gel) and SBA-15-Al (Si/Al = 5 in gel) showed a high and durable acidity activity in the cracking reaction of cumene. The high level Al incorporated (in gel) into mesoporous structure (Al-MCM-41-2.5, SBA-15-Al-5) with direct-synthesis or post-synthesis method still retain the hexagonal structure order and without any significant degradation in the textural properties of MCM-41 and SBA-15.
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