DIELECTRIC AND HYDROGEN-BONDING EFFECTS OF SOLVENTS ON BASE-CATALYSED REACTION OF PHENYL GLYCIDYL ETHER WITH BENZOIC ACID

The effect of the dielectric character of a solvent on the pyridine-catalyzed reaction between phenyl glycidyl ether and benzoic acid was studied in various pure and mixed aromatic hydrocarbons such as toluene, monochlorobenzene, o-dichlorobenzene, nitrotoluene, nitrobenzene, and toluene-nitrobenzene mixtures at temperatures ranging from 80 to 180°, and is discussed in terms of the modified Kirkwood's expression. The hydrogen-bonding effect of the solvent was also investigated for this reaction in toluene-dioxan and nitrobenzene-dioxan mixtures at temperatures ranging from 80 to 100° and in various ethers such as tetrahydrofuran, anisole and di-n-butyl ether at 65°0°. A linear relationship was found between the logarithm of the third order rate constants and pKa values of solvents, and can be described by the proposed rate equation. These show that in aromatic hydrocarbons the nonspecific electrical interactions are predominant, while the hydrogen-bonding character of the solvent can explain reasonably the rate data in solvents containing ethers, and should also suggest that the activated complex or the transition state species proposed plays an important role for this reaction in these solvents. © 1968.