Reaction of Metastable Ar Atoms with Propylene in Flow System

Article abstract of DOI:10.1246/bcsj.54.678

The reaction of metastable Ar atoms with propylene was studied in a discharge flow system.The major product is ethylene, although ethane, propane and butadiene are also identified as minor products.Within a limited range of propylene concentration the yield of ethylene is proportional to the concentration of propylene.Competitive quenching methods using mixtures of propylene and N2O or CO2 provided a rate constant of (8.4+/-0.3) * 10^-10 cm³ molecule^-1 s^-1 for the reaction of metastable Ar atom with propylene to yield ethylene.The assumption of a radical mechanism for the main reaction is consistent with the results of competitive quenching, radical scavenger and spin trapping experiments.Measurements of ion current in the reaction mixtures allow an estimation that ionic species contribute less than 2percent to the reaction path leading to the formation of ethylene.The metastable Ar atom reaction was also compared to the direct and mercury-sensitized photolysis of propylene.