Fe2+ activating persulfate selectively oxidized alcohols by biphasic/homogeneous reaction switch strategy

A facile and efficient oxidation of alcohol by Fe 2+ activating persulfate was performed and a homogeneous/biphasic reaction switch strategy was proposed to regulate the oxidation process. Na 2 S 2 O 8 and FeSO 4 were employed as the oxidant and the source of activator Fe(II), respectively. Fe 2+ efficiently excited persulfate, endowing persulfate with powerful oxidation activity. Benefited from this, the oxidation of benzylic primary alcohols and cyclic secondary alcohols could proceed to give the corresponding aldehydes or ketones with good yields (85.2–98.5%) under the optimal conditions of 60 °C, 1.5 mol equivalent Na 2 S 2 O 8 and 0.3 mol equivalent Fe 2+ to substrate in a water/dichloroethane biphase system. Moreover, the primary alcohols were one-step oxidized into carboxylic acids with high selectivity by raising reaction temperature, increasing the amount of oxidant and switching from biphasic reaction to the water/MeCN homogeneous phase.