Please use this identifier to cite or link to this item: http://hdl.handle.net/11455/3284
標題: Oxidation of Propane over The Supported Metal Oxide Catalysts
被擔持金屬氧化物之丙烷氧化反應研究
作者: 鄭樵陽
Cheng, Chiao -Yang
關鍵字: the supported metal oxide catalyst;被擔持金屬氧化物觸媒;oxidation of propane;Reducibility;Promoters;丙烷氧化反應;還原能力;增促劑
出版社: 化學工程學系
摘要: 
ABSTRACT
The current abundance and low cost of alkanes has generated much interest in the oxidative catalytic conversion of alkanes and oxygenates in the petroleum and petrochemical industries. A review of the literature reveals that the oxidation of alkanes is the most efficient over vanadia-based catalysts. The bonded properties between supported vanadium oxide and support play an important role in oxidation dehydrogenation. The supportedvanadium (molybdenum,chromium) oxide on the titania support will be used as the potential model catalysts for propane oxidation. Moreover, supported rhenium catalysts and a series of the supported vanadium catalysts on TiO2 and Al2O3 will also be studied to explore the difference on oxidative dehydrogenation of propane.
The model supported vanadium oxide catalysts as well as supported molybdenum oxide catalyst possess dual functionality (redox/acid activity). A good fitting of the acidic-basic and redox properties of the catalyst surface controls the reactivity and selectivity of propane oxidation. In this study, Rhenium oxide is used as a promoter to improve the catalysis properties of propane oxidative dehydrogenation over the model supported vanadium (molybdenum or chromium) oxide catalysts. The catalysts be prepared by Incipient wetness impregnation method, and the surface analysis is charactized by using Raman, TPR, BET surface area and FTIR. Furthermore, the catalysis properties of propane oxidation over the model catalysts will be optimized by the C3H8/O2 feed ratio equal to 1、3、6 and the reaction temperature .The results reveal that the selectivity of adding Re promoter is higher than 1%V2O5/TiO2、3%MoO3/TiO2、1%CrO3/TiO2, respectively, but is low than the Re/TiO2catalyst. In the surface properties analysis show that the ability of reduction increase and the amount of acidic sites are decreased after adding Re promoter. However, the reactive result reveal that the selectivity of acrolein decreases with increasing the amount of acidic sites. It appears that the acidic sites on catalysts relate with the selectivity of main products, and the ratio of C3H8/O2 in the feed can affect the selectivity of propene and acrolein for model supported vanadium oxide catalysts on different supports, but there isn’t evident trend on the selectivity of propene and acrolein for MoO3/TiO2、CrO3/TiO2 catalyst. This can be related to the improvement of the reducibility of the promoted catalyst.

中文摘要:
由於近十年來,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過程逐漸引起研究者之注意及興趣。目前的研究結果顯示以釩為主之觸媒最能有效應用於烷類之氧化反應。被擔持氧化物和擔體的性質在氧化脫氫反應上扮演著一個重要的角色。
所需的觸媒利用沈浸法製備,並運用拉曼(Raman)、傅利葉紅外光譜(FTIR)、BET表面分析與孔洞分佈及溫控程式還原反應來作觸媒表面特性分析。再以進料比:丙烷/氧氣=1、3、6的比例進行氧化脫氫反應,以此來探討催化反應特性以及氧氣對整個反應的影響。結果顯示:發現關於被擔持釩氧化物觸媒,對於不同的進料比並不會對反應活性產生影響,但對於丙烯的選擇率會因C3H8/O2 之值的變大而增加,對丙烯醛則是相反的。在加入Re增促劑於以TiO2為擔體的被擔持金屬氧化物觸媒中,與未加入增促劑的觸媒而做比較,發現觸媒表面的路易士酸性基位會因此而減少。對還原性而言,表面CrOx、MoOx和VOx的還原性皆有改變,且在觸媒表面上並不是以結晶狀或複合體狀存在,此由Raman光譜可看出。在催化反應結果中,Re增促劑的加入,對丙烯、丙烯醛的選擇率是有所影響的,且發現丙烯醛選擇率會隨路易士酸性基位的減少而降低之趨勢,但對丙烯的選擇率之變化則是有上升的趨勢,但是效果以C3H8/O2 =3時為最好。故認定路易士酸性基位是觸媒表面上控制產生何種產物的重要依據。
URI: http://hdl.handle.net/11455/3284
Appears in Collections:化學工程學系所

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