Abstract
The controlled surface reaction of an organometallic compound, such as tetrabutyl tin, with hydrogen covered rhodium particles supported on silica leads to a very well defined superficial organometallic species. These superficial organometallic species are characterized by rhodium-tin bonds and contains butyl radicals still linked to tin atoms. As the temperature of the hydrogen thermal treatment is increased, butyl radicals are progressively eliminated leading at last to the formation of bulky rhodium-tin alloy particles.
The presence of these butyl radicals at the surface of the metallic particles induces an increase not only in selectivity but also in activity regarding the hydrogenation of the carbonyl function of an unsaturated aldehyde such as citral.