LABORATORY CHEMICAL SAFETY SUMMARY: BUTYLLITHIUMS

Substance

Butyllithiums (and related alkyl lithium reagents)

n-butyllithium: CAS 109-72-8

s-butyllithium (1-methylpropyllithium): CAS 598-30-1

t-butyllithium (1,1-dimethylethyllithium): CAS 594-19-4

Formula

C4H9Li

Physical Properties

Usually supplied and handled as solutions in ether or hydrocarbon solvents

Odor

Odor of the solvent

Toxicity Data

There is little toxicity data available for the butyllithiums; for data on ether and hydrocarbon solvents, see the appropriate LCSSs.

Major Hazards

Highly reactive; violent reactions may occur on exposure to water, CO2 and other materials; may ignite spontaneously on exposure to air; highly corrosive to the skin and eyes.

Toxicity

Solutions of the butyllithiums are corrosive to the skin, eyes, and mucous membranes. Reaction with water generates highly corrosive lithium alkoxides and lithium hydroxide.

Flammability and Explosibility

The risk of fire or explosion on exposure of butyllithium solutions to the atmosphere depends on the identity of the organolithium compound, the nature of the solvent, the concentration of the solution, and the humidity. t-Butyllithium solutions are the most pyrophoric and may ignite spontaneously on exposure to air. Dilute solutions (1.6 M, 15% or less) of n-butyllithium in hydrocarbon solvents, although highly flammable, have a low degree of pyrophoricity and do not spontaneously ignite. Under normal laboratory conditions (25 °C, relative humidity of 70% or less), solutions of -20% concentration will usually not ignite spontaneously on exposure to air. More concentrated solutions of n-butyllithium (50 to 80%) are most dangerous and will immediately ignite on exposure to air. Contact with water or moist materials can lead to fires and explosions, and the butyllithiums also react violently with oxygen.

Reactivity and Incompatibility

The butyllithiums are extremely reactive organometallic compounds. Violent explosions occur on contact with water with ignition of the solvent and of the butane produced. t-Butyllithium will ignite spontaneously in air. The butyllithiums ignite on contact with water, carbon dioxide, and halogenated hydrocarbons. The butyllithiums are incompatible with acids, halogenated hydrocarbons, alcohols, and many other classes of organic compounds.

Storage and Handling

Butyllithium solutions should be handled in the laboratory using the "basic prudent practices" described in Chapter 5.C, supplemented by the additional precautions for work with flammable (Chapter 5.F) and reactive (Chapter 5.G) substances. In particular, butyllithium should be stored and handled in areas free of ignition sources, and containers of butyllithium should be stored under an inert atmosphere. Work with butyllithium



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