V. I. Mil’to, V. Yu. Orlov, G. S. Mironov, and V. V. Kopeikin
Yaroslavl State University, Yaroslavl, 150000 Russia
Received February 9, 2000
Abstract—The kinetics of 4-nitrochlorobenzene (4-NCB) reactions with substituted phenols in the presence
of potassium carbonate in N,N-dimethylacetamide was studied. Depending substituents, the reactivity of the
phenols is changed in the series 3-NO2 > 4-Cl > H > 4-Br > 3-CH3 > 3-NH2, which is consistent with the series
of their acidity. The reaction rates satisfactorily correlate with the pKa values of the corresponding substituted
phenols. Based on kinetic data (first-order and zero-order reactions with respect to phenol and 4-NCB, respec-
tively, and the consistency of the reactivity and acidity of substituted phenols), the deprotonation of phenols is
considered as the rate-determining step of the overall reaction under the test conditions. A reaction scheme was
proposed for the synthesis of diaryl ethers in the presence of potassium carbonate. It involves a heterogeneous
step of phenol deprotonation, which takes place on the surface of potassium carbonate, and a homogeneous step
of the interaction of potassium phenolates with 4-NCB. Under the reaction conditions, the resulting bicarbonate
decomposes with the formation of potassium carbonate and with the release of carbon dioxide and water.
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