Preparation of lithium acetylide
Alternative Names: lithium ethynide; lithium hydrogenacetylide; ethynyllithium; lithium ethyne;
To a 2 litre three-necked flask fitted with a mechanical stirrer and surrounded by a cooling bath at —35° C, 1 liter of liquid ammonia and 0.2 g finely powdered hydrated ferric nitrate are placed. Then 1 g of clean lithium while stirring is introduced in small pieces, where a vigorous effervescence of hydrogen takes place, indicating the conversion of the metallic lithium into lithium amide, and the initial deep blue colour due to dissolved lithium rapidly changes to the black color of the suspension of finely-divided iron produced. 6 g of lithium are added in 1 g lumps over fifteen minutes (a useful alternative technique is to impale the lumps of lithium on the end of a stout iron wire and immerse them in the ammonia solution; in this way the possibility of the jamming of the lithium between the stirrer and the base of the flask is avoided). A pale grey suspension of lithium amide is thus obtained. A gaseous acetylene, which is purified by passage through a carbon dioxide-acetone-cooled trap and then through two half-filled 500 ml concentrated sulfuric acid wash bottles, preferably of the sintered glass type is passed via a simple mercury safety valve, into the stirred, cooled (—35° C) lithium amide suspension at a rate of 2-3 litres per minute until the grey reaction mixture becomes uniformly black. Sometimes this colour change is indefinite but passage of the acetylene at the above rate for 1 hour ensures complete conversion to lithium acetylide. The concentration of the solution of lithium acetylide in liquid ammonia produced by the above procedure is about 1M. The lithium acetylide solution thus prepared is ready for acetylene chemistry reactions.
Acetylenic compounds in organic synthesis, by R. R. Alexander, 193-194, 1955
lithium ethynide, Lithium hydrogenacetylide, 1111-64-4, ethynyllithium, lithium ethyne, lithium acetylenide, AC1N5DPI, CHEBI:51481, CTK8D8720, EINECS 214-182-6, AR-1J3242
CID101973, CID4193444, 112227-15-3