Selective homogeneous hydrogenation of alk-1-enes using hydridocarbonyltris(triphenylphosphine)rhodium(I) as catalyst

Abstract

The complex hydridocarbonyltris(triphenylphosphine)rhodium(I), RhH(CO)(PPh3)3, has been shown to be an efficient catalyst for the homogeneous hydrogenation of unsaturated compounds of the formula RCH=CH2. For hex-1-ene and dec-1-ene in benzene solution, the rate law has been found to be: Rate = k1K1c[S][A]/(1 + K 1[S]) where [S] and [A] are the concentrations of alk-1-ene and catalyst respectively, c is the concentration of hydrogen in solution, K 1 is the formation constant for an alkene intermediate complex, and k1 is the rate constant for the rate determining, hydrogen activation step. The high selectivity for the reduction of alk-1-ene is attributed to steric factors caused by the bulky triphenylphosphine groups.