Ethylene Epoxidation on Ag-Cs/-Al2O3 Catalyst: Experimental Results and Strategy for Kinetic Parameter Determi

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• 作者：David Lafarga ; Mohammed A. Al-Juaied ; Christina M. Bondy ; and Arvind Varma
• 刊名：Industrial & Engineering Chemistry Research
• 出版年：2000
• 出版时间：July 2000
• 年：2000
• 卷：39
• 期：7
• 页码：2148 - 2156
• 全文大小：118K
• 年卷期：v.39,no.7(July 2000)
• ISSN：1520-5045

文摘

The kinetics of ethylene epoxidation network were studied experimentally over a cesium-dopedsilver catalyst supported on alpha.gif" BORDER=0>-Al₂O₃ pellets in a differential reactor. A variety of rate functionswere considered and among these, expressions based on a dual-site Langmuir-Hinselwoodmechanism: r_i = k_iP_Eals/iecred/39/i07/eqn/ie990939xe10001.gif">/(1 + als/iecred/39/i07/eqn/ie990939xe10002.gif"> P_E)², fitted the data best with an average error of 13.0 and10.7% for the epoxidation and the complete combustion reactions, respectively. Under theexperimental conditions, both reactants influence both reaction rates; however, product influenceis negligible because of their small partial pressures present in the reactor. High oxygen/ethyleneratios and lower temperature favored selectivity to the epoxidation reaction. The kineticparameters obtained from the differential reactor experiments were refined to match the fixed-bed reactor experiments. With this, the average error in predicting both ethylene conversionand selectivity to ethylene oxide was 4.3%. The apparent activation energies for the epoxidationand combustion reactions were 60.7 and 73.2 kJ/mol, respectively.