Lithium borohydride

Chemical properties

WHITE POWDER

Physical properties

White orthorhombic crystals; density 0.67 g/cm³; decomposes in moist air; melts at 268°C; decomposes at 380°C; reacts with water; dissolves in ether, tetrahydrofuran, and diethylamine; solubility in ether, 25g/L at 25°C.

The Uses of Lithium borohydride

Strong reducing agent. Used to reduce compounds containing ketones, aldehydes, ester carbonyls, acid chlorides, lactones, and epoxidesLithium borohydride is a versatile reducing agent for aldehydes, ketones, nitriles, primary amides, acid chlorides, lactones, epoxides, and esters. It is involved in the preparation of intercalation compounds and nanocomposites. It is used as a precursor for other borohydrides and acts as a catalyst in hydroboration reactions. It is known to be good reversible storage compound for anhydrous ammonia and hydrogen.

The Uses of Lithium borohydride

To a solution of the SM (300 mg, 0.9 mmol) in THF (15 mL) at -78 C was added dropwise LiBH4 (1.8 mL, 1.8 mmol). The reaction mixture was stirred at -78 C for 5 min, after which time it was quenched with sat aq NH4Cl. The mixture was filtered and the filtrate was extracted with EtOAc (3 x 30 mL). The combined organics were dried and concentrated to provide the product as a yellow solid. [110 mg, 48%]

The Uses of Lithium borohydride

Strong reducing agent. Used in the reduction of Compounds contg ketonic, aldehydic, or ester carbonyls and a nitrile group, where reduction of the carbonyl, but not of the nitrile group, is wanted. In the determination of free carboxyl groups in peptides and proteins; after esterification and acetylation, only the ester groups, and none of the peptide bonds are reduced.

The Uses of Lithium borohydride

Lithium borohydride (LiBH₄) is a complex hydride with a high hydrogen density. It is a strong reducing agent and an electrode material. It has a high gravimetric (18.4 wt%) and volumetric (121 kg/m³) hydrogen storage capacities. It can also be used in lithium-ion batteries.

What are the applications of Application

Lithium borohydride is a reducing agent for esters

General Description

A white to grayish crystalline powder.

Air & Water Reactions

Likely to ignite when moistened with water [Lab. Gov. Chemist 1965].

Reactivity Profile

Lithium borohydride is a strong reducing agent. Is easily ignited and burns vigorously once ignited. Reacts on contact with water or acids to form hydrogen gas and corrosive products. Reaction with limited amounts of water or moisture may cause ignition after a delay [Gaylord, 1965, p. 22].

Health Hazard

Inhalation or contact with vapors, substance or decomposition products may cause severe injury or death. May produce corrosive solutions on contact with water. Fire will produce irritating, corrosive and/or toxic gases. Runoff from fire control may cause pollution.

Fire Hazard

Produce flammable gases on contact with water. May ignite on contact with water or moist air. Some react vigorously or explosively on contact with water. May be ignited by heat, sparks or flames. May re-ignite after fire is extinguished. Some are transported in highly flammable liquids. Runoff may create fire or explosion hazard.

Safety Profile

Poison by ingestion, inhalation, and skin contact. Flammable; can liberate H2. Incompatible with H20 as moisture on fibers of cellulose or as liquid. See also LITHIUM, BORON COMPOUNDS, and HYDRIDES.

Purification Methods

It is crystallised from Et2O, and pumped free of ether at 90-100o during 2hours [Schaeffer et al. J Am Chem Soc 78 729 1956]. Store it dry as it decomposes slowly in moist air. [Becher in Handbook of Preparative Inorganic Chemistry (Ed. Brauer) Academic Press Vol I p 775 1963.]