Observation of 3-Hexene-2,5-dione in the Photooxidation of 1,2,4-Trimethylbenzene in the NO-H2O-Air System

Formation of 3-hexene-2,5-dione (diacetylethylene) was observed in the photooxidation of 1,2,4-trimethylbenzene in the mixture of NO-H2O-air. The 3-hexene-2,5-dione is a larger aromatic ring-ruptured compound than has been reported. Although the yield of 3-hexene-2,5-dione collected was very low, the formation of 3-hexene-2,5-dione showed that the formation of other large dicarbonyl compounds due to the cleavage reaction of aromatic ring is possible in the photooxidation of aromatic hydrocarbons. Formation of 3-hexene-2,5-dione was also observed in the photooxidation of the p-xylene system.