When and where we use liquid ammonia and NaNH2
Dear Student,
If you were add sodium amide (NaNH2) to water in an attempt to carry out a reaction using the amide ion (NH2-) as a very powerful base, the following reaction would take place immediately;
The amide ion would react with water to produce a solution containing hydroxide ion and ammonia. this example illustrates what is called the levelling effect of the solvent. Water, the solvent here, donates a proton to any base stronger than a hydroxide ion.
Therefore it is not possible to use a base stronger than hydroxide ion in aqueous solution.
We can use bases stronger than hydroxide ion, however, if we choose solvent such as hexane, diethyl ether, or liquid NH3. All of these solvents are very weak acids and therefore they will not donate a proton even to the strong base NH2-.
For example: Convert ethyne to its conjugate base, a carbanion, by treating it with sodium amide in liquid ammonia:
If you were add sodium amide (NaNH2) to water in an attempt to carry out a reaction using the amide ion (NH2-) as a very powerful base, the following reaction would take place immediately;
The amide ion would react with water to produce a solution containing hydroxide ion and ammonia. this example illustrates what is called the levelling effect of the solvent. Water, the solvent here, donates a proton to any base stronger than a hydroxide ion.
Therefore it is not possible to use a base stronger than hydroxide ion in aqueous solution.
We can use bases stronger than hydroxide ion, however, if we choose solvent such as hexane, diethyl ether, or liquid NH3. All of these solvents are very weak acids and therefore they will not donate a proton even to the strong base NH2-.
For example: Convert ethyne to its conjugate base, a carbanion, by treating it with sodium amide in liquid ammonia:
Hope this information will clear your doubts about topic.
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