The epoxidation of propene using molten salts has been investigated. This manner of direct propene epoxidation has been developed by Olin, claiming propene oxide selectivities of up to 65% at 15% propene conversion. A number of different molten salt mixtures were applied and several components were added in an attempt to increase selectivity. By comparing the epoxidation results in the molten salts to experiments using the same, but empty reactors, an attempt was made to clarify the mode of operation of the salt. It was concluded that the salt acts as a catalyst in the formation of free radicals, necessary for the homogeneous gas-phase oxidation taking place in the gas bubbles present in the molten salt medium. The salt, therefore, does not actually take part in the oxidation reaction, but only acts as an initiator to the radical reaction process.