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4576342 
Journal Article 
Macrokinetics of Ethylene Epoxidation over A-type Silver Catalyst 
Liang Rujun; Li Jianwei 
2015 
0 
China Petroleum Processing and Petrochemical Technology
ISSN: 1008-6234 
17 
3 
44-52 
WOS:000365020700012 
By taking the surface chemical reactions as the rate-controlling step, a possible reaction mechanism for ethylene epoxidation to synthesize ethylene oxide over the A-type silver catalyst was developed, while it was assumed that the epoxidation reaction would take place between ethylene and the un-dissociated adsorbed oxygen O-2a on the solo active sites, while the deep oxidation would occur between ethylene and the dissociated adsorbed oxygen O-a on the adjacent multi-active sites. In order to describe the effect of 1,2-C2H4Cl2 (EDC) inhibitor on the ethylene epoxidation process, the reversible reactions between EDC and vinyl chloride (VC) on the active sites of silver catalyst was introduced. According to the assumed mechanism, the hyperbolic macro-kinetic model of ethylene epoxidation over the A-type silver catalyst was established, and the macrokinetic experiments were carried out in an internal-recycle gradientless reactor operating at a pressure of 2.1 MPa and a temperature in the range of 217.8-249.0 degrees C, with the gas composition (molar fraction) consisting of 15.82%-34.65% C2H4, 2.55%-7.80% O-2, 0.88%-6.15% CO2, 0.15-2.61 mu mol/mol of 1,2-C2H4Cl2 and 0.14-1.28 mu mol/mol of C2H3Cl. By means of the Simplex Optimal Method, the parameters of the macrokinetic models were estimated. Statistical test showed that the macrokinetic models developed for the A-type silver catalyst agree well with the experimental results. 
silver catalyst; ethylene epoxidation; reaction mechanism; macrokinetics