THE IMPACT OF SURFACE ORGANOMETALLIC CHEMISTRY IN HETEROGENEOUS CATALYSIS - A NEW CLASS OF HIGHLY CHEMOSELECTIVE HYDROGENATION CATALYSTS, RHSSN(N-C4H9)2/SIO2

A bi-metallic RhSSn(C4H9)2/SiO2 catalyst can be obtained by partial hydrogenolysis, at 423 K, of Sn(n-C4H9)4 on surface rhodium atoms (Rh(S)) of Rh(0) particles supported on SiO2. The catalyst has been found to be extremely active and selective in the hydrogenation of citral (geranial and neral) to the corresponding unsaturated alcohols (geraniol and nerol): 96% selectivity at 100% conversion. This selectivity is observed when the rhodium particles are covered with Sn(C4H9)x fragments. These fragments are coordinated to naked zero-valent tin atoms, as determined by various analytical and spectroscopic methods.