Sodium amide

Off-white solid with ammoniacal odor

Fixed

1.39 g · cm -3

210 ° C.

400 ° C.

Decomposition in water

Risk

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Sodium amide is a colorless, coarsely crystalline or powdery compound of the composition NaNH2.

Representation

Sodium is displayed on a laboratory scale from metallic sodium and liquid ammonia in the presence of iron ( III) ions with the liberation of hydrogen.

Without iron catalyst, the amide is not formed ( unlike the analog synthesis of sodium hydroxide from sodium and water), instead it comes to the solvation of the 3s valence electron of sodium in ammonia. The free electrons lead to a deep blue color of the solution, which are in a sense be regarded as e - ammoniacal solution of the hypothetical " salt " Na . Evaporated, the solution a, Na is again reduced to the element, the yield of NaNH2 amounts so only to less than 0.5 %.

Properties

Sodium amide is a colorless, hygroscopic solid. It is a very strong base which is suitable for deprotonation only weakly acidic compounds.

Responsiveness

With water sodium reacts violently to sodium hydroxide and ammonia .. The violence of the reaction is comparable to that of sodium and water.

By atmospheric oxygen sodium is oxidized slowly, partly form explosive reaction products such as sodium hyponitrite, Natriumtrioxodinitrat, Natriumtetraoxodinitrat and higher Peroxonitrate. The oxidation products are highly sensitive to friction and impact. Even simple Mahlungs, crushing and transferring liquids can lead to violent explosions. The formation of unstable oxidation products can be recognized by discoloration of the material. It is therefore recommended the compound in a protective liquid ( petroleum ) maintain or better to consume immediately. Old, oxidized preparations are no longer useful and must be disposed of reasonable precautions.

Use

Sodium amide is used in organic chemistry as a strong base to deprotonate little acidic compounds. So can be obtained with sodium amide by a E1cb reaction, for example, the highly strained arynes by reacting bromobenzene. Rare sodium is also used to deprotonate alcohols or terminal alkynes.

Thus, from acetylene obtained by deprotonation of sodium acetylide be used for the alkynylation. Since sodium is sterically less demanding, it is also used for the deprotonation sterically poorly accessible protons. Furthermore, it may be used for the production of sodium azide.

As a nucleophile, it acts in the Chichibabin reaction, in which it acts nucleophilically on a pyridine ring with the formation of aminopyridines.