Reactions of symmetrical aromatic mercury compounds with phenols

Summary

• 1. It was shown that diaryl mercury compounds of general formula (RC₆H₄)₂Hg (R = NH₂, NO₂, OCH₃, and OH) are able to mercurate phenols at 70–150° with formation of mono-, di-, and tri-mercurated compounds.

• 2. The rate of mercuration and the composition of the products vary with the nature of the substituents present in the organomercury compound and in the phenol.

• 3. With respect to reactivity the compounds (RC₆H₄)₂Hg) can be arranged in the series:

  $$\begin{gathered} (p - H_2 NC_6 H_4 )_2 Hg > (o - HOC_6 H_4 )_2 Hg > (p - CH_3 OC_6 H_4 )_2 Hg > (m - NO_2 C_6 H_4 )Hg > \hfill \\ > (o - NO_2 C_6 H_4 )_2 Hg > (p - HOOCC_6 H_4 )_2 Hg \hfill \\ \end{gathered} $$

• 4. Phenols having substituents of the “first kind” (p-cresol, resorcinol, chlorophenols) are mercurated more readily than phenols having substituents of the “second kind” (nitrophenols).

• 5. A free-radical mechanism is proposed for the mercuration of phenols by mercury compounds of formula (RC₆H₄)₂Hg.