Resumen de Unimolecular Nucleophilic Substitution (SN1): Structural Reactivity Evidenced by Colored Acid–Base Indicators

Willber D. Castro-Godoy, Juan E. Argüello, Marisa Martinelli, Daniel A. Caminos

• The different reactivities between 1°, 2°, and 3° butyl chlorides by the unimolecular nucleophilic substitution (SN1) mechanism were easily observed at 60 °C by a solvolysis reaction in ethanol with ether formation. The hydrogen ion from the byproduct HCl reacted with an acid–base indicator such as methyl red to induce a color change. At room temperature, the addition of AgNO3 was used to detect the released chloride ion by AgCl precipitation. The reactivity order (3° > 2° ≫1°) was visually confirmed by both a color change in an indicator and precipitate formation by these safe, quick, and easy assays.