Question

Br2 dissolves in a number of solvents, but we preferentially use glacial acetic acid. Explain why acetic acid is a good solvent for electrophilic bromination reactions. (Is it polar protic, polar aprotic or non-polar? How might that be important in this reaction?)

Answer 1

For electrophilic bromination reactions, we need to generate the actual electrophile that takes part in the reaction, namely bromonium ion [Br⁺]. To generate this we need to use a polar protic solvent like water or acetic acid.

Acetic acid is preferred over water as many organic compounds like alkenes( on which electrophilic brominations occur) are more readily soluble than in water, makes the reaction more facile.

Thus acetic acid is a good solvent for electrophilic brominations.

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