PHOTOISOMERIZATION OF 5-HEXEN-2-ONE,
Abstract:
The photochemistry of 5-hexen-2-one has been studied in the vapor phase in the temperature range from 27 to 139 degrees at 3130 angstroms and also with radiation from an unfiltered mercury arc. The compound was found be very stable towards photolysis. The most important product at 3130 angstroms up to 139 degrees was an isomer, whose structure is indicated in the report. Evidence for the structure is based on the ultraviolet, infrared, nuclear magnetic resonance, and mass spectra of the product. The only other product at 3130 angstroms that was identified was carbon monoxide. At shorter wavelengths, in addition to these products, methane, C2 and C3 hydrocarbons, acetone and biacetyl were identified. Although the ultraviolet absorption spectrum of 5-hexen2-one resembles that of 2-hexanone, its photochemical stability is similar to that of unsaturated carbonyl compounds with the double bond conjugated with the carbonyl group. Author