RADIATION-INDUCED ISOMERIZATION OF STILBENE IN2-PROPANOL AND ACETONE

The radiation-induced isomerization of stilbene was studied in 2-propanol and acetone. In 2-propanol the precursors of the trans-to-cis isomerization are shown to be ionic species, while an energy-transfer mechanism is operative in acetone. The cis-to-trans isomerization in both solvents was found to be catalyzed by radiation-produced intermediates of the solvents, most probably electrons. In mixtures of acetone in 2-propanol the amount of isomerization of trans-stilbene indicated that a reaction between acetone triplets and 2-propanol was competing with the energy-transfer process between acetone triplets and trans-stilbene.