Polymerisation and related reactions involving nucleophilic aromatic substitution. Part 2. The rates of reaction of substituted 4-halogenobenzophenones with the salts of substituted hydroquinones

Abstract

4-X-4′-Fluorobenzophenones undergo the expected nucleophilic substitution reactions with the alkalimetal salts of 4-Y-4′-hydroxydiphenyl ethers at 140 °C in diphenyl sulphone as solvent: the Hammett ρ value is 1.02 for the X substituents and –0.34 for the Y substituents. The order of reactivity of the alkali metal salts is Cs > K > Na. The related reaction of fluorobenzophenone with potassium 4-Z-phenolates under the same conditions gives a ρ value of –2.28. This result has been used to calculate the corresponding rate coefficients for the reaction of the mono- and di-potassium salts of hydroquinone with fluorobenzophenone.