Active hydrogenation catalysts from titanium complexes and alkali metal hydrides

Hydrogenation of 1-hexene was catalyzed by titanium complexes allowed to react in situ with active alkali metal hydrides. Under normal temperature and pressure, a maximum turnover number of 2270 min−1 was obtained using Cp2TiCl2/NaH as catalyst, while a high turnover of 9290 in 80 min was achieved using a less active but more stable catalyst [C6H10(p-CH3OC6H4)C5H4]2TiCl2/NaH. The hydrogenation rates using these catalysts have a very low temperature dependence, and are still very high even at −30°C. The use of active NaH and KH as cocatalysts is the key point for the high catalyst activities.