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Updated: Jun 27, 2026
09:45
A Protocol for Safe Lithiation Reactions Using Organolithium Reagents
Published on: November 12, 2016
リチウムアルミニウム水化物の再生
Jason Graetz1, James Wegrzyn, James J Reilly
1Energy Sciences and Technology Department, Brookhaven National Laboratory, Upton, New York 11933, USA.
Journal of the American Chemical Society
|December 5, 2008
まとめ
リチウムアルミニウム水化物 (LiAlH(4) は,その分解産物から低エネルギー経路を用いて再生することができる. この方法は,効率的な水素貯蔵材料回収のための有望な経路を提供します.
科学分野:
- マテリアルサイエンス 材料科学
- 化学工学は化学工学というものです.
- エネルギー貯蔵 エネルギー貯蔵
背景:
- リチウムアルミニウム水化物 (LiAlH ((4)) は,高い水素密度と低い分解温度のため,水素貯蔵のための重要な材料です.
- 脱水産物 (LiHとAl) からLiAlH(4) を再生することは,実用的な圧力での直接的な水素化経路がないため,困難です.
研究 の 目的:
- LiHとTi-触媒化されたAl.からLiAlH(4) を再生するための低エネルギーメソッドの開発と実証.
- 再生プロセスの熱力学的性質を調査する.
主な方法:
- テトラヒドロフランスラージでLiHとTi-触媒化されたAlを水素化し,LiAlH(4).4THFアダクトを形成する.
- 反応熱力学を決定するために,圧力組成イソテルムの測定.
- アダクトを低温で溶解して結晶のLiAlHを生成する.
主要な成果:
- LiAlH(4) の再生のための低エネルギー経路が成功裏に実証されました.
- 逆転反応は,小さな,わずかに負の自由エネルギー (ΔG = -1.1 kJ/mol H) を表します.
- 300 Kで1bar未満の均衡水素圧が反応のために決定されました.
結論:
- 開発された方法は,LiAlH ((4)) の再生のための効率的な経路を提供し,水素貯蔵におけるその応用に不可欠です.
- 熱力学的データは,穏やかな条件下で再生プロセスの実現可能性を示唆しています.
- 低温溶解により結晶のLiAlH(4) が生成され,その後の使用に適しています.
関連する概念動画
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...
01:17Esters to Alcohols: Hydride Reductions
Esters are reduced to primary alcohols when treated with a strong reducing agent like lithium aluminum hydride. The reaction requires two equivalents of the reducing agent and proceeds via an aldehyde intermediate.
Lithium aluminum hydride is a source of hydride ions and functions as a nucleophile. The mechanism proceeds in three steps. Firstly, the nucleophilic hydride ion attacks the carbonyl carbon of the ester to form a tetrahedral intermediate. Subsequently, the carbonyl group re-forms,...
Lithium aluminum hydride is a source of hydride ions and functions as a nucleophile. The mechanism proceeds in three steps. Firstly, the nucleophilic hydride ion attacks the carbonyl carbon of the ester to form a tetrahedral intermediate. Subsequently, the carbonyl group re-forms,...
01:20Amides to Amines: LiAlH4 Reduction
Amide reduction with strong reducing agents like lithium aluminum hydride proceeds through a nucleophilic acyl substitution to form amines. Primary, secondary, and tertiary amides yield primary, secondary, and tertiary amines, respectively.
Amide reduction requires two equivalents of the reducing agent, acting as a source of hydride ions. As shown in the figure, the reaction is initiated with a nucleophilic attack by the hydride ion at the carbonyl carbon to form a tetrahedral intermediate.
Amide reduction requires two equivalents of the reducing agent, acting as a source of hydride ions. As shown in the figure, the reaction is initiated with a nucleophilic attack by the hydride ion at the carbonyl carbon to form a tetrahedral intermediate.
00:55Nitriles to Amines: LiAlH4 Reduction
Nitriles are reduced to amines in the presence of strong reducing agents like lithium aluminum hydride through a typical nucleophilic acyl substitution. The reaction requires two equivalents of the reducing agent. The reducing agent acts as a source of hydride ions.
As shown below, the mechanism involves three steps. Firstly, the hydride ion acting as a nucleophile attacks the nitrile carbon to form an anion. In the second step, a second equivalent of the hydride ion attacks the anion to...
As shown below, the mechanism involves three steps. Firstly, the hydride ion acting as a nucleophile attacks the nitrile carbon to form an anion. In the second step, a second equivalent of the hydride ion attacks the anion to...
01:15Acid Halides to Alcohols: Grignard Reaction
Organomagnesium halides, commonly known as Grignard reagents, convert acid halides to tertiary alcohols. The reaction requires two equivalents of the Grignard reagent and proceeds via a ketone intermediate.
Grignard reagents are a source of carbanions and function as nucleophiles. The mechanism begins with the nucleophilic attack by the carbanion at the carbonyl carbon of the acid halide to form a tetrahedral intermediate. Next, the carbonyl group is re-formed, and the halide ion departs,...
Grignard reagents are a source of carbanions and function as nucleophiles. The mechanism begins with the nucleophilic attack by the carbanion at the carbonyl carbon of the acid halide to form a tetrahedral intermediate. Next, the carbonyl group is re-formed, and the halide ion departs,...
01:24Preparation of Aldehydes and Ketones from Nitriles and Carboxylic Acids
Although it is possible to reduce a carboxylic acid to an aldehyde, strong reducing agents, like lithium aluminum hydride (LAH), prohibit a controlled reduction, instead causing the generated aldehyde to instantly over-reduce to a primary alcohol.
Reducing carboxylic acid derivatives like acyl chlorides (RCOCl), esters (RCO2R′), and nitriles (RCN) using milder aluminum hydride agents like lithium tri-tert-butoxyaluminum hydride [LiAlH(O-t-Bu)3] and diisobutylaluminum hydride [DIBAL-H] allows...
Reducing carboxylic acid derivatives like acyl chlorides (RCOCl), esters (RCO2R′), and nitriles (RCN) using milder aluminum hydride agents like lithium tri-tert-butoxyaluminum hydride [LiAlH(O-t-Bu)3] and diisobutylaluminum hydride [DIBAL-H] allows...