Alcohol Phenols And Ethers

$\mathrm{CO}_2, 6 \mathrm{~atm} \mathrm{~H}_3 \mathrm{O}^{+}$

$\mathrm{CHCl}_3$, aq. $\mathrm{NaOH}, \mathrm{H}_3 \mathrm{O}^{+}$

$\mathrm{CS}_2$ (at low temperature)

$\mathrm{Na}_2 \mathrm{Cr}_2 \mathrm{O}_7 / \mathrm{H}_2 \mathrm{SO}_4$