Please use this identifier to cite or link to this item: http://hdl.handle.net/11455/3497
標題: 不同過渡金屬添加於矽酸鹽觸媒之結構與氧化反應研究
The addition transition metals with MCM-41 for structure and oxidation reaction
作者: 黃晁熙
Huang, Chao-Hsi
關鍵字: Mesoporous
中孔洞觸媒
MCM-41
propane oxidation
矽酸鹽
丙烷氧化脫氫反應
出版社: 化學工程學系
摘要: MCM-41 is the designation of a new of mesoporous structure. The first synthesized mesoporous solid was showed a regularly ordered pore arrangement and a very narrow pore-size distribution. The research interest focused on the characterization and the technical applications. The structure of metallosilicate catalysts was studied as a function of various transition metals and metal concentrations. The uniform mesoporous structure in metallosilicate ([M]-MCM-41, [M]= W, Mo, Ta, Co, Ni and Cr) catalysts was confirmed by X-ray diffraction, BET surface area and TEM technique. The different metal additive would result in larger pore size. The higher the concentration was, the larger the pore size will be. Incorporation of transition metals into the wall structure is necessary in the preparation of mesoporous redox-catalysts. Due to the success of Ti-MCM-41 and V-MCM-41.We appraise the metallosilicate and selecting suitable catalysts to experiment on propane oxidation reaction. The propane oxidation will be optimized by the C3H8/O2 feed ratio equal to 1、3、6 with 450℃、500℃ and 550℃ reaction temperature. The reaction product concentration was detected by GC analysis and confirmed the products are propene and other by-products, CO2, CH4, C2H4, C2H6 etc. In the results of analytic data, by increasing temperature, catalysts got higher conversion and selectivity became lower. When increase the oxygen feed ratio, the by-products CO and CO2 is increasing. Besides, the propene yields are getting more with the increasing of metal concentrations in silicalite at first. Then it would get a maximum yield in every series of metallosilicate catalysts and drop off afterward. So catalyst’s ability indeed related to the concentrations of metal additive.
MCM-41為新型態之中孔洞矽酸鹽觸媒之代表,由於孔洞為規則排列的六角型態且具有極高的表面積和高孔洞體積,即受到研究人員廣泛的注意與應用。由文獻中得知加入少量的金屬可改變MCM-41之不同的催化能力,且前人研究得知,Ti-MCM-41、V-MCM-41應用烷烴、烯烴、和醇類氧化還原反應上有極佳的效果。因此本實驗加入不同價數之過渡金屬(鎢、鉬、鉭、鈷、鎳、鉻)等金屬及不同金屬濃度對金屬矽酸鹽觸媒結構特性之影響,經由X光繞射儀、BET表面積及TEM之測試結果,確定其屬於中孔洞型態之金屬矽酸鹽觸媒,且金屬之添加會使其孔洞加大。添加不同金屬於矽酸鹽,隨添加金屬之濃度增加,光譜之變化愈大,金屬可能與矽氧形成鍵結於主結構中或形成表面金屬型態。 綜合以上特性分析結果針對金屬矽酸鹽觸媒進行評估,並進行丙烷氧化反應,且以不同丙烷與氧之進料比( 1:1、3:1、6:1)於450℃、500℃、550℃下反應,利用氣相層析儀分析產物濃度。反應結果主產物為丙烯,副產物為一氧化碳、二氧化碳、甲烷、乙烯、乙烷等。歸納反應結果,隨溫度之增加,觸媒轉化率愈高,而高氧氣進料比時丙烷轉化率也會比低氧氣進料比時高。而丙烯選擇率則隨著溫度的上升有下降的趨勢;於低氧氣進料比,丙烯選擇率則會比高氧氣進料比高。隨著氧進料比越大丙烷容易過度氧化而副產物一氧化碳、二氧化碳則增多。此外在每一系列之金屬矽酸鹽觸媒中,丙烯產率有隨著添加之金屬濃度增加而上升至一極大值,可見添加金屬濃度和催化能力有密切的關係。
URI: http://hdl.handle.net/11455/3497
Appears in Collections:化學工程學系所

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