Rate constants for the reaction of diphenyl carbonyl oxide with phenols

The kinetics of the reaction of diphenyl carbonyl oxide Ph2COO with o- and p-substituted phenols is studied by pulse photolysis and high-speed spectro photometry. The rate constant strongly depends on the phenol structure and ranges from 1.3 x 10(3) for ionol to 2.1 x 10(8) 1 mol(-1) s(-1) for o-amin olphenol. A U-shaped curve illustrating how the logarithm of the rate const ant changes with a change in the Hammett constants (sigma (0)) of the subst ituents in the aromatic ring is found for the studied compounds. Possible p athways for the reaction of Ph2COO with phenols are discussed.