Phenols, flash-photolysis aqueous solutions

Following the classical observation of Lewis and his school (29, 30, 34) of the photoionization of aromatic molecules in rigid solvents, Land, Porter and Strachan (25) proved such processes in the flash photolysis of aqueous solutions of phenols. It was suggested (7, 15, 25, 38) that the primary photochemical act involves electron ejection. 

The two keto tautomers of phenol 3, i.e. 4 and 5, were generated by flash photolysis of polycyclic precursors 6-8 in aqueous solution, and the pH-rate profiles of their 4 3 and 5 3 enolization reactions were measured. The rates of the reverse reactions, 3 4 and 3 5, were determined from the rates of acid-catalyzed hydrogen exchange at the ortho- and para-positions of phenol 3 (equation 3). 

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