As mentioned, our proposed PO formation pathway (see Fig. ) is far from being the only possible reaction pathway. We compared common synthesis methods for ethylene oxide and propylene oxide and selected further candidate reactions for the PO formation within our experiments. All reactions requiring an aqueous environment and specific catalysts were dismissed, as neither were present in our experiments. We identified three further reaction mechanisms that could be considered within our setup. First, we look at the direct oxidation of ethene used to synthesize ethylene oxide according to equation 3.