BUTADIENE HYDROGENATION ON RH-CU AND RH-A G MODEL CATALYSTS

The addition of copper or silver by metal evaporation on a rhodium foi l leads to significant modifications of the catalytic and structural p roperties of rhodium measured by XPS and by butadiene hydrogenation. T he addition of copper or silver improves the selectivities of rhodium in butene1 and butene2 trans and cis at the expense of butane. Neverth eless, the addition of a big amount of Cu or Ag destroys the activitie s for the reaction products. These results may be explained by a geome tric effect of silver on rhodium and the formation of copper-rhodium a lloy which alters the catalytic properties of rhodium irreversibly.