Alkyl iodides are synthesized in the Finkelstein reaction by reacting alkyl chlorides or bromides with NaI in dry acetone. NaCl or NaBr formed is precipitated, facilitating the forward reaction according to Le Chatelier’s Principle.
How is the synthesis of alkyl iodides achieved in the Finkelstein reaction, and what is the role of NaI in this process?
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The Finkelstein reaction involves the synthesis of alkyl iodides from alkyl chlorides or alkyl bromides by exchanging the halide ion. In the presence of sodium iodide (NaI) in acetone or other polar solvents, the nucleophilic iodide ion (I-) replaces the nucleofuge (Cl- or Br-) in the alkyl chloride or bromide. The reaction occurs via a nucleophilic substitution mechanism, resulting in the formation of alkyl iodide. NaI plays a crucial role as the source of iodide ions, facilitating the substitution process. The reaction conditions favor the formation of alkyl iodides due to the relatively higher reactivity of iodide ions.