Abstract: The hydrogenation of 1-hexene was catalyzed by titanocene with varioussubstituted groups in combination with nanometric sodium hydride. When the steric hindrance ofthe substituted group on the cyclopentadienyl ring is relatively small, the titanium complexgives high initial catalytic activity but poor stability, whereas when the steric hindrance islarge (for instance, five-membered ring or six-membered ring), the titanium complex giveslower initial catalytic acitivty but better stabilty. At normal temperature and pressure, amaximum turnover frequency(TOF_max) of H₂/(mol Ti·s) and a turnover(TO) of22200 mol H₂/(mol Ti) were obtained by using bis [(1'-ethyl)cyclohexyl-cyclopentadiTiCl₂/NaH^*as catalyst. Only the terminal olefin could be hydrogenated by using this kind ofcatalytic system. Isomerization of olefins did not occur in the course of hydrogenation. It isthe key factor that the nanometric NaH^*was used as the cocatalyst in the reaction. Thecombination of titanocenes with commercial sodium hydride which was synthesized at hightemperatures did not display any catalytic activity for the hydrogenation of 1-hexene.

Key words: Titanocenes, Nanometric sodium hydride, Catalytic hydrogenation, Olefins