Chemical Properties
crystal(s) white powder(s); decomposes in water, evolves acetylene when dissolved in acid [HAW93]
Uses
Dilithium Acetylide could be used as dianion and as bistrimethylsilyl derivative finds use in the synthesis of variously substituted alkynes, alkenes, γ-diketones, etc.; preferred over its sodium counterpart in reactions with enolizable carbonyls
Preparation
Lithium carbide, Li2C2, may be prepared by the direct combination of lithium and
carbon at about 1000°C or by the reaction of lithium metal with acetylene in liquid ammonia.
The latter process first yields lithium acetylide, LiC=CH, which decomposes to lithium
carbide. The conversion to the carbide is incomplete, however . A convenient laboratory
preparation of lithium carbide may be carried out by bubbling acetylene into a solution of
n-butyllithium in hexane. The precipitated carbide may be filtered from the reaction
mixture, washed, and dried. Lithium carbide is ionic and yields acetylene on hydrolysis.
Precautions
Dilithium Acetylide is highly moisture sensitive; very short exposure to air under good ventilation is allowed. Use of a freshly prepared solution is advised. Use in a fume hood.
