Department of Chemistry, University of New Brunswick, P.O. Box 4400, Fredericton, New Brunswick E3B 5A3, Canada.
J Am Chem Soc. 2011 Oct 5;133(39):15593-7. doi: 10.1021/ja204976z. Epub 2011 Sep 8.
The direct synthesis of LiAlH(4) from commercially available LiH and Al powders in the presence of TiCl(3) and Me(2)O has been achieved for the first time. The effects of TiCl(3) loadings (Ti/Al = 0, 0.01, 0.05, 0.2, 0.5, 1.0 and 2.0%) and various other additives (TiCl(3)/Al(2)O(3), metallic Ti, Nb(2)O(5), and NbCl(5)) on the formation and stability of LiAlH(4) have been systematically investigated. The yield of LiAlH(4) initially increases, and then decreases, with increasing TiCl(3) loadings. LiH + Al → LiAlH(4) yields above 95% were obtained when the molar ratios of Ti/Al were 0.05 and 0.2%. In the presence of a very tiny amount of TiCl(3) (Ti/Al = 0.01%), LiAlH(4) is still generated, but the yield is lower. In the complete absence of TiCl(3), LiAlH(4) does not form. Addition of metallic Ti, Nb(2)O(5), and NbCl(5) to commercial LiH and Al does not result in the formation of LiAlH(4). Preliminary tests show that TiCl(3)-doped LiAlH(4) can be cycled, making it a suitable candidate for hydrogen storage.
首次实现了在 TiCl3 和 Me2O 的存在下，由商业上可获得的 LiH 和 Al 粉末直接合成 LiAlH4。系统研究了 TiCl3 负载量（Ti/Al=0、0.01、0.05、0.2、0.5、1.0 和 2.0%）和各种其他添加剂（TiCl3/Al2O3、金属 Ti、Nb2O5 和 NbCl5）对 LiAlH4 的形成和稳定性的影响。LiAlH4 的产率最初随着 TiCl3 负载量的增加而增加，然后降低。当摩尔比 Ti/Al 为 0.05 和 0.2%时，LiH+Al→LiAlH4 的产率超过 95%。当 TiCl3 的量非常小（Ti/Al=0.01%）时，仍然生成 LiAlH4，但产率较低。在完全不存在 TiCl3 的情况下，LiAlH4 不会形成。向商业 LiH 和 Al 添加金属 Ti、Nb2O5 和 NbCl5 不会导致 LiAlH4 的形成。初步测试表明，TiCl3 掺杂的 LiAlH4 可以循环使用，使其成为储氢的合适候选物。
