Polymerisation and Related Reactions involving Nucleophilic Aromatic Substitution. Part 1. The Rates of Reaction of Substituted 4-Halogenobenzophenones with the Potassium Salts of Substituted 4-Hydroxybenzophenones

Article abstract of DOI:10.1039/P29880001729

The rate of displacement of fluorine from 4'-X,4-fluorobenzophenones by the potassium salts of 4'-X,4-hydroxybenzophenones (X = CF3, Cl, F, H, OPh, and OMe) has been studied at 175-225 deg C in diphenyl sulphone as solvent.Comparison with the corresponding rate of displacement of chlorine indicates that the reaction is a bimolecular nucleophilic aromatic substitution.The reaction obeys the Hammett equation using normal ? values for substitution in both the substrate (ρ 1.19) and the phenolate (ρ -0.53).There is also a marked salt effect on the reaction rate and this has been included with the substituent constants in a general equation for the calculation of rate coefficients.The effect of an O^- substituent is more marked than would have been expected from the previous range of ? values ascribed to this substituent.