Partial oxidation of ethane into acetaldehyde and acrolein by oxygen over silica-supported bismuth catalysts

摘要

Selective oxidation of ethane by oxygen was examined over silica catalysts supporting cesium and bismuth. Aldehydes f Cl-C3 were obtained withtQtal selectivity of about 40% at ethane conversion lower than 5%. The catalytic perfonnance 'as strongly dependent upon the bismuth loading on the catalysts. The higher tum-over-rate and the higher selectivity ) aldehydes were observed at the Bi loadings lower than 0.5%. Characterization of the catalysts showed that isolated or ighly dispersed Bi on the catalyst ~urface wa& indispensable for the high aldehyde yield. Cesium also plays an important >le for the high ethane reactivity and the high aldehyde selectivity. A reaction pathway was proposed in which ethane is I(idized into acetaldehyde, but not through ethylene, and acrolein is fonned thro!gh a cross-condensation of acetaldehyde .1d fonnaldehvde.