Reactions of nonequilibrium oxygen plasmas with liquid olefins

The oxidation of 13 liquid olefins with either high-voltage or radiofrequen cy (RF) glow discharges has been studied The reactions were carried out by making the oxygen plasma reach the low vapor pressure substrate. Product fo rmation has proved to be selective-epoxides, aldehydes, ketones, and low qu antities of carboxylic acids being the most important species. Fragmentatio n products were only observed in the traps of the RF system for the most vo latile olefin of this study. This indicates that, except for this case, the most relevant interaction of this study has been the heterogeneous reactio n of the plasma with the liquid. Total conversion, i.e., mass transformed a gainst initial mass of substrate, has been studied as a function of tempera ture of the liquid and oxygen flow rate in the reactor, this ranging from 1 5 to 53.6 mmol/hr in the high-voltage system and 13 to 270 mmol/hr in the R F device. The optimum conversions were 27 to 99%. A correlation between the se results and the behavior of the O(P-3) population in the discharge allow s us to conclude that this is the most relevant species to the oxidation pr ocess. A discussion relating the structures of the olefins with the composi tion of the mixtures produced by the oxidation is also presented.