| 摘 要： | The surface characteristics and catalytic activity of Sb_xO_Y/ SiO_2 catalysts forvapor-phasc synthesis of isoprene from isobutylene and formaldehyde have been investi-gated by TPR, XRD, XPS, IR and catalytic activity evaluation. The results show that whenthe Sb loadings are less than about 5 wt%,Sb_xO_Y is compIctely dispersed on the surface ofsilica to form a surface compound with Sb(V)=O group and the catalysts have relativelyhigh catalytic activity; when the Sb loadings are more than 5 wt%, in addition to this surfacccompound, the crystalline α-Sb_2O_4 is formed on the support surface and causes rapid de-crease of catalytic activity. It is suggcsted that the catalytic activity of Sb_xO_Y /siO_2 catalystsresults from synetgistic catalysis of the surface compound Sb(V)=O as the basic sites andthe surface silanol Si-OH as the acidie sites. The mechanism of this synergistic catalysis forisoprene production is discussed.
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