Please use this identifier to cite or link to this item: http://hdl.handle.net/11455/3318
標題: Novel Metallosilicate Catalysts for Propane Oxidation
金屬矽酸鹽觸媒於丙烷氧化反應之應用
作者: 顏維廷
Yen, Wei-Ting
關鍵字: 中孔洞;Mesoporous;矽酸鹽;丙烷氧化脫氫反應;Silicalite;Propane oxidation;MCM-41;Ti-silicalite;V-silicalite;Nb-silicalite;W-silicalite
出版社: 化學工程學系
摘要: 
The structure of metallosilicate catalysts was studied as a function of various metal and metal concentrations. The uniform mesoporous structure in metallosilicate ([M]-MCM-41, [M]= Nb, Ti, V, W) catalysts was confirmed by X-ray diffraction and BET surface area technique. The different metal additive would result in larger pore size. The higher the concentration was, the larger the pore size will be. It was also confirmed that pure silicalite (MCM-41) has similar structure as the amorphous silica by Raman spectroscopy. Furthermore, Raman spectra of metallosilicate have dramatically changed by increasing the metal concentration in all metallosilicate catalysts. These metals would be bonded with Si in main structure or formed surface metal. The metal of Ti and V were present as tetrahedral structure and Nb was present as octahedral structure into metallosilicate. Summarizing all the characterization techniques, appraising the metallosilicate and selecting suitable catalysts to experiment on propane oxidation reaction.
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, Nb-silicalite catalyst had the lowest conversion and yield among the catalysts. V-silicalite catalyst had the best yield in propene. But Ti-silicalite got higher selectivity(~86%) than V-silicalite. By increasing temperature, catalysts got higher conversion and selectivity became lower and lower.
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.

由於近十年來,烷類產量過剩及成本低之因素,在石油及石油化學工業中將烷類催化氧化轉變成烯類及含氧化物之製程日漸提高研究者之注意及興趣。
MCM-41為一新型態之中孔洞矽酸鹽觸媒,其孔洞為規則的六角型態且具有極高的表面積。根據文獻加入少量的金屬可改變MCM-41之催化能力且不會破壞原有之結構,因此本實驗中分析加入鈮、鈦、釩、鎢等不同金屬及金屬濃度對金屬矽酸鹽觸媒結構特性之影響,經由X光繞射儀及BET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。拉曼光譜之結果確定純矽酸鹽(MCM-41)與非結晶性二氧化矽之振動光譜相似,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。金屬鈦及釩形成四面體結構,而金屬鈮形成八面體結構於金屬矽酸鹽結構中。
綜合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以氣相層析儀分析產物濃度。反應結果主產物為丙烯,副產物為二氧化碳、甲烷、乙烯、乙烷。歸納反應結果,鈮系列之觸媒的反應轉化率及產率最差,鈦系列觸媒在較低金屬濃度時丙烯產率高於釩系列觸媒,在高濃度時則以釩系列觸媒的丙烯產率最高,但選擇率則以鈦系列之觸媒表現較佳(~86%選擇率)。隨溫度之增加,觸媒轉化率愈高,而選擇率則隨著溫度的上升有下降的趨勢。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,可見添加金屬和催化能力有密切的關係。
URI: http://hdl.handle.net/11455/3318
Appears in Collections:化學工程學系所

Show full item record
 

Google ScholarTM

Check


Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.