lithiumaluminiumhydride

Lithium aluminium hydride (LiAlH4) is a white to off-white crystalline solid and a widely used strong reducing agent in organic synthesis. It contains hydride ions delivered from the aluminum center, making it a powerful source of hydride for reductions.

It is highly reactive with water and air; contact with moisture liberates hydrogen gas and heat. It is typically handled and stored under strictly dry, inert conditions in a suitable solvent such as diethyl ether or tetrahydrofuran (THF).

Common reductions include the conversion of aldehydes and ketones to primary and secondary alcohols, respectively; esters and carboxylic acids to primary alcohols; amides to amines; nitriles to primary amines; and epoxides to alcohols. It can also reduce some halides to alkanes. Aromatic rings are generally resistant to LiAlH4 under standard conditions.

Preparation of LiAlH4 is typically achieved by reacting lithium hydride with aluminium trichloride in an anhydrous ether solvent, or via related routes that combine lithium and aluminium hydride components.

Safety and handling: LiAlH4 is moisture sensitive and evolves hydrogen gas on contact with water or protic solvents, requiring careful handling under inert atmosphere. Spills and disposal should follow appropriate chemical safety guidelines to minimize fire and exposure hazards.