用于储存的Ti-doped LiAlH4:合成,催化剂加载和循环性能
Xiangfeng Liu1, Henrietta W Langmi, Shane D Beattie
1Department of Chemistry, University of New Brunswick, P.O. Box 4400, Fredericton, New Brunswick E3B 5A3, Canada.
Journal of the American Chemical Society
|August 26, 2011
概括
现在可以使用化 (LiH) 和 (Al) 粉与化 (TiCl3) 直接合成化 (LiAlH4). 优化的TiCl3度产生超过95%的LiAlH4,这是储存的有希望的材料.
科学领域:
- 材料科学 材料科学 材料科学
- 无机化学 无机化学
- 化学工程是化学工程的重要组成部分.
背景情况:
- 化 (LiAlH4) 是储存的一个关键材料.
- 现有的LiAlH4合成方法可能是复杂的或低效的.
- 开发直接合成路径对于实际应用至关重要.
研究的目的:
- 从LiH和Al粉末中实现LiAlH4的直接合成.
- 为了研究TiCl3对LiAlH4形成的催化作用.
- 探索各种添加剂对LiAlH4产量和稳定性的影响.
主要方法:
- 在TiCl3和乙烯 (Me2O) 的存在下,LiH和Al粉末的直接反应.
- TiCl3度的系统变化 (Ti/Al比率从0到2.0%之间).
- 测试其他添加剂,包括TiCl3/Al2O3,金属Ti,Nb2O5和NbCl5.5.
主要成果:
- 首次成功地实现了LiAlH4的直接合成.
- 在最佳的TiCl3负载下 (Ti/Al=0.05%和0.2%) 获得超过95%的LiAlH4产量.
- TiCl3对于LiAlH4的形成是必不可少的;它的缺失阻止了合成. 其他测试的添加剂没有促进LiAlH4的形成.
结论:
- TiCl3作为LiAlH4.4直接合成的关键催化剂.
- 优化的TiCl3兴奋剂显著提高LiAlH4产量.
- TiCl3-合的LiAlH4显示了可逆储存应用的潜力.
相关概念视频
01:19Acid Halides to Alcohols: LiAlH4 Reduction
Acid halides are reduced to alcohols in the presence of a strong reducing agent like lithium aluminum hydride.
The mechanism proceeds in three steps. First, the nucleophilic hydride ion attacks the carbonyl carbon of the acid halide to form a tetrahedral intermediate. Next, the carbonyl group is re-formed, and the halide ion departs as a leaving group, generating an aldehyde. A second nucleophilic attack by the hydride yields an alkoxide ion, which, upon protonation, gives a primary alcohol as...
The mechanism proceeds in three steps. First, the nucleophilic hydride ion attacks the carbonyl carbon of the acid halide to form a tetrahedral intermediate. Next, the carbonyl group is re-formed, and the halide ion departs as a leaving group, generating an aldehyde. A second nucleophilic attack by the hydride yields an alkoxide ion, which, upon protonation, gives a primary alcohol as...
02:17Reduction of Alkenes: Asymmetric Catalytic Hydrogenation
Catalytic hydrogenation of alkenes is a transition-metal catalyzed reduction of the double bond using molecular hydrogen to give alkanes. The mode of hydrogen addition follows syn stereochemistry.
The metal catalyst used can be either heterogeneous or homogeneous. When hydrogenation of an alkene generates a chiral center, a pair of enantiomeric products is expected to form. However, an enantiomeric excess of one of the products can be facilitated using an enantioselective reaction or an...
The metal catalyst used can be either heterogeneous or homogeneous. When hydrogenation of an alkene generates a chiral center, a pair of enantiomeric products is expected to form. However, an enantiomeric excess of one of the products can be facilitated using an enantioselective reaction or an...