Flash photolysis studies in a time-of-flight mass spectrometer. I. Divinyl ether and reactions of the vinyl and vinoxy radicals

The lower pressure flash photolysis of divinyl ether has been monitored by time-of-flight mass spectrometry. The primary photodecomposition process is restricted essentially to the formation of vinyl and vinoxy radials: C2H3OC2H3→C2H3+C2H3O. The vinyl radical (m/e=27) has been observed directly and its 2nd order decay constant measured. The decay is primarily by disproportionation 2C2H3→C2H4+C2H2 and k10 has an average value of 5.3± 0.5× 10−12cc molecule−1·sec−1 over the pressure range studied (65–200 mtorr). The vinoxy radical has not been observed directly in this work. Our results favor a rapid isomerization, followed by decomposition C2H3O⇄CH3CO→CH3+CO. A mass balance is achieved within 400 μsec of the photolysis flash and a mechanism proposed to account for the major (C2H4, C2H2, CO) and the minor products (CH4, C2H6, 2-butenal, acetaldehyde, and ketene).