直接利用甲烷氧化偶联产物中的稀乙烯制环氧乙烷

探讨了直接利用甲烷氧化偶联产品中的稀乙烯制取环氧乙烷的可能性。在负载银催化剂上，分别考察了一氧化碳、氢气、二氧化碳、甲烷等对乙烯环氧化反应的影响。将乙烯的转化率保持在４０％（环氧乙烷的选择性为７０％，２８０℃，各单组份影响实验表明，在原料气中加入的一氧化碳完全转化为二氧化碳后，乙烯的转化率和环氧乙烷的选择性没有受到影响。而当一氧化碳转化不完全时，由于催化剂表面积炭，导致乙烯和一氧化碳的转化率下降。氢气可使催化剂中的氯流失，补加浓度为１０￣（－６）级的二氯乙烷可消除这一影响。原料气中加入的二氧化碳浓度超过２．６％时，对乙烯的环氧化反应有抑制作用。原料气中加入一氧化碳、氢气、甲烷并加入浓度为１０￣（－６）级的二氯乙烷的试验结果与上述单组份结果相同，乙烯的环氧化反应没有受到影响。

Utilization of Ethylene in the Product Streams of Oxidative Coupling of Methane for the Production of Ethylene Oxide over Supported Silver Catalysts

The epoxidation of etliylene over supported silver catalysts promoted with Ba, Cs and Clin the presence of added hydrogen,carbon monoxide,carbon dioxide and methane was studied as a possible method for directly using ethylene in the product streams from the oxi- dative coupling of methane(OCM).Under conditions of moderate ethylene conversion(ca. 40%,at 280℃),ethylene epoxidation、was not affected when carbon monoxide in the streamswas completely oxidized.However,either ethylene conversion,selectivity to ethylene oxide(EO)or carbon monoxide conversion was affected significantly when carbon monoxide was incom-pletely oxidized owing to carbon deposited on the catalyst surface. Selectivity to ethylene oxidedecreased while ethylene conversion increased gradually when hydrogen was added to thestream. The effect was due to rapidly stripping of chlorine impregnated in the catalysts byhydrogen. The effect of hydrogen could be avoided by adding 5.6ppm 1,2-dichloroethane tothe streams.Both hydrogen and carbon monoxide were oxidized much faster than ethylene overthe supported silver catalysts. The inhibiting effect of carbon dioxide on epoxidation of eth-ylene was serious when the amount of carbon dioxide was beyond 2.6%in the streams.Thecombined effect of adding together hydrogen, carbon monoxide and methane and dichloroeth-ane at ppm Ievel to the streams was the same as that caused by separate addition of thesesubstalices.