Abstract: The effects of substituted group on the cyclopentadienyl ring and various operating factors including the amount of catalyst, the operating procedure,the solvents, the airand water-free conditions on the catalytic activity and stability of titanocene/n-BuLi catalyst system have been investigated.When there is no substituted group on the cyclopentadienyl ring or the substituted group is relatively small,the titanium complex exhibits a very high initial catalytic activity,e.g., the TOF_max(or TOF_initial)of titanocenes {Cp₂TiCl₂,Cp₂TiF₂ or Cp₂Ti[OC₆H₃(CH₃-2)Cl-4]₂}/n-BuLi system may reach 46～58 s^-1 for the hydrogenation of l-octene; whereas when the substituted group is larger,the titanium complex exhibits a lower initial catalytic activity but better stability.

Key words: Titanocene, n-Butyl lithium, Hydrogenation catalyst, Ligand effect