Photoepoxidation of Propylene at Elevated Pressures Sensitized by α-Diketones

Article abstract of DOI:10.1021/jo00151a012

The α-diketone sensitized photooxygenation of saturated propylene solutions (o-dichlorobenzene) at atmospheric pressure proceeds with high selectivity to propylene oxide.The effect of changing sensitizer concentration on the rate of epoxidation was determined for biacetyl, 1-phenyl-1,2-propanedione, and benzil.A small enhancement of the rate was achieved by using mixtures of biacetyl and 1-phenyl-1,2-propanedione.Pressurization of the reaction (140-185 psia) allowed the use of greater solution concentrations of propylene and oxygen and resulted in significant rateenhancement.In concentrated propylene solutions (<*>3.2 M) the formation of epoxide decreased as oxidative cleavage to acetaldehyde and formaldehyde increased.Total propylene conversion remained relatively constant at these concentrations.