CATALYTIC HYDROGENATION OF 1,3-trans-PENTADIENE OVER Rh4(CO)12 SUPPORTED ON γ-Al2O3

Article abstract of DOI:10.1016/S0022-328X(00)85146-3

Rh4(CO)12 anchored on γ-Al2O3 (Rh4(CO)12/Al2O3) has been studied as a catalyst for the hydrogenation of 1,3-trans-pentadiene.Under mild conditions (1 atm H2 and temperatures between 60 deg C and 80 deg C) hydrogenation occurs at only one of the double bonds of the diene, and analysis of the products shows that the terminal double bond is preferentially hydrogenated.Hydrogenation of the second double bond of the conjugated diene occurring only after all the 1,3-trans-pentadiene has been consumed.In this respect Rh4(CO)12/Al2O3 behaves like toluene solutions of Rh4(CO)12.Anchoring of Rh4(CO)12 on the solid support gives a catalyst which is less active but more stable than toluene solutions of Rh4(CO)12.The effects of CO and of triphenylphosphine on catalytic activity and on specificity of Rh4(CO)12/Al2O3 have also been investigated and both shown to cause a reduction of the rate of hydrogenation of 1,3-trans-pentadiene.