aprotic solvent

This term is a specialized technical designation used almost exclusively within organic chemistry and materials science. It describes a solvent that cannot act as a Brønsted-Lowry acid, meaning it lacks a hydrogen atom bonded to an electronegative atom like oxygen or nitrogen, which prevents it from donating protons to the reacting species.

In a laboratory setting, the choice of an aprotic solvent is critical for reactions involving strong nucleophiles. Because these solvents do not solvate anions as strongly as protic solvents do, they increase the reactivity of the nucleophile, which is essential for specific mechanisms like the SN2 reaction.