TiCl3

Schäfer et al. reported on the reduction of TiCl4 with elemental aluminum or titanium at 923 K (650 °C), or even with mercury at room temperature for preparation of TiCl3 powder.[49–51] Coutinho et al. described the synthesis of TiCl3 by reduction of TiCl4 with di-n-buthyl ether and diethylaluminum chloride in an iso-octane solution or with triethylaluminum in toluene solution.[52] It is shown, that depending on the applied reaction system, different modifications of TiCl3 (α, β, γ or δ) were obtained, which was confirmed later by Costa.[53] Lewis et al. reported on the preparation of TiCl3 by reduction of TiCl4 with hydrogen at 1173 K (900 °C).[54] Likewise, Higuchi et al. used commercial TiCl3, but noted that this batch was prepared by electrolysis of TiCl4 with elemental titanium.[55] Similarly, Miyaoka et al. described α-TiCl3 was synthesized by reduction of TiCl4 vapor in the plasma arc generated by several titanium electrodes.[56],[54] Natta et al. stated that high reduction temperatures mainly lead to the alpha modification (α-TiCl3), while lower temperatures lead to primarily β-TiCl3 by application of any reducing agents, that was confirmed by further investigation.[57–60] In contrast to α- and β-TiCl3, γ-TiCl3 was prepared by reduction of TiCl4 with organometallic compounds at 448 K (175 °C).[57]