A process for oxidizing a first hydrocarbon to a corresponding first oxygenate by feeding a first feedstock comprising the first hydrocarbon into an oxidation reactor, contacting the reaction medium with a gas stream comprising O2 in the oxidation reactor, and supplying a hydroperoxide additive to the oxidation reactor. By including the hydroperoxide additive in the reaction medium, foaming at and/or close to the beginning of the oxidation reaction can be significantly reduced.