Synthesis of sodium acetylide

Preparation of sodium acetylide (sodium ethynide; ethynyl sodium)

Preparation of sodium acetylide (sodium ethynide; ethynyl sodium)

Preparation of sodium acetylide (sodium ethynide; ethynyl sodium)

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 sodium while stirring is introduced in small pieces, where a vigorous effervescence of hydrogen takes place, indicating the conversion of the metallic sodium into sodium amide, and the initial deep blue colour due to dissolved sodium rapidly changes to the black color of the suspension of finely-divided iron produced. 22 g of sodium are added in 1 g lumps over fifteen minutes (a useful alternative technique is to impale the lumps of sodium 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 sodium between the stirrer and the base of the flask is avoided). A pale grey suspension of sodium 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) sodium 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 sodium acetylide. The concentration of the solution of sodium acetylide in liquid ammonia produced by the above procedure is about 1M. A saturated solution of sodium acetylide in liquid ammonia at —35° C of is 4M. The sodium acetylide solution thus prepared is ready for acetylene chemistry reactions.

Acetylenic compounds in organic synthesis, by R. R. Alexander, 193-194, 1955





InChI Key


Canonical SMILES


Depositor-Supplied Synonyms

sodium ethynide, Ethynyl sodium, Sodium acetylide, Sodium acetylide suspension, Sodium acetylide (Na(C2H)), 1066-26-8, ethynylsodium, sodium ethyne, AC1MBYNF, AC1Q1UKL, 249572_ALDRICH, CHEBI:55387, CTK8D8256, CTK8E5879, MolPort-001-788-027, SLBNQJAGYKQCKI-UHFFFAOYSA-N, EINECS 213-908-9, 6893AF, AR-1L5089, AKOS005258173, AKOS009158902, TR-001317, 1720-39-4

Removed Synonyms

CID101954, CID2733336, 6328-09-2, 99435-46-8

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