• 作者： Chang, June-Cheng; Chou, Tse-Chuan
• 中文摘要： 本文探討氧化鋁擔體性質對含浸於其上鈀金屬分散性及濃度分布的影響,同時並研究此鈀觸媒在異戊二烯選擇性氫化反應的催化性能。將.gamma.-氧化鋁在300,800,1000,及1050.degree.C煆燒,可得到.gamma.(350.degree.C),. gamma.(800.degree.C),.delta.,.theta./.alpha.四種不同擔體,具三種結晶相。性能測試是利用以上擔體含浸鈀金屬後的觸媒在與商用製程相近的條件下進行反應(40.degree.C,30atm)。觸媒以X-射線繞射,一氧化碳化學吸附,氨程溫脫附,快速傅立葉轉換紅外線光譜,及電子微探分析等儀器進行特性分析。實驗結果顯示鈀金屬分散性,起始活性,起始異戊烯選擇性,及觸媒的穩定性均受觸媒擔體種類的影響; 而鈀金屬濃度分布及穩定狀態下的異戊烯選擇性卻不受其影響。.gamma.(350.degree.C)鈀金屬觸媒由於有較高的鈀金屬分散性,故其起始活性及起始異戊烯選擇性較高; 但也因具有較高的酸性,致使其老化速率最快。在以上四種擔體中,.delta.鈀金屬觸媒由於在反應穩定狀態下有較高的氫化活性,可視為異戊二烯選擇性氫化反應之最佳觸媒。
• 英文摘要： The effects of support properties on metal dispersion and metal deposition profile of alumina-supported Pd catalysts and their corresponding catalytic performances in the selective hydrogenation of isoprene were investigated. The catalytic tests were carried out at 40.degree.C and 30atm, which are similar to the reaction conditions of a commercial unit. The catalysts were characterized by X-ray diffraction (XRD), CO chemisorption, temperature-programmed desorption (TPD) of ammonia, fast-Fourier transform infrared(FFT-IR) for the CO adsorption on the catalysts and electron probe microanalysis (EPMA). Four alumina supports of .gamma.(350.degree.C), .gamma. (800.degree.C), .delta., and.theta./.alpha. form were prepared. The experimental results indicated that the metal dispersion, initial activity, initial selectivity to isopentenes, and catalyst stability are greatly influenced by the types of catalyst support, whereas the support properties have no influence on metal deposition profile and selectivity to isopentenes at nearly steady state. The trend of initial activity and selectivity to isopentenes is consistent with the metal dispersion. Due to its higher Pd dispersion, the .gamma. (350.degree.C)- alumina-supported Pd catalyst has the higher initial activity. It also has higher acid amount leading to quicker deactivation. As a consequence, among four catalyst samples , the .delta.-alumina-supported Pd catalyst having the highest hydrogenation activity was regarded as the optimal catalyst for selective hydrogenation of isoprene.
• 中文關鍵字： 鈀; 觸媒; 擔體; 氧化鋁; 氫化; 選擇性
• 英文關鍵字： Palladium; Catalyst; Support; Alumina Oxide; Hydrogenation; Selectivity