Abstract
Some applications of surface organometallic chemistry on metals to catalysis are presented, showing the great importance of the modification of a metallic surface by organometallic compounds on its catalytic properties. The selective hydrogenation of alpha-beta unsaturated aldehydes such as citral (Z and E) can be achieved on rhodium-tin catalysts. While rhodium alone is relatively unselective, geraniol (and nerol) can be obtained selectively (> 98%) without a significant loss of activity by use of a rhodium-tin catalyst showing a typical ligand effect of the organotin fragment on the surface. Similarly, in the isomerization of (+) 3-carene into (+) 2-carene or the dehydrogenation of butan-2-ol into methyl ethyl ketone, the selectivity into the desired product is increased by introduction of small amounts of tin which will form adatoms poisoning unselective sites. An alloying effect of tin is also presented in the dehydrogenation reaction of isobutane in isobutene.