Studies of Solvolyses of Biphenyl-4-carbonyl Chloride by Extended Grunwald-Winstein Equation

The solvolysis rate constants of biphenyl-4-carbonyl chloride (C6H5C6H5COCl, 1) in 19 different solvents are well correlated with the extended Grunwald-Winstein equation, using the NT solvent nucleophilicity scale, YCl solvent ioniz- ing scale, and I aromatic ring parameter with sensitivity values of 0.31±0.10, 0.46±0.05, and 0.96±0.20 for l, m, and h, respec- tively. These l, m, and h values can be considered to support a dissciative SN2 reaction pathway. This interpretation is further supported by the activation parameters, i.e., relatively small positive ΔH ‡ (15.3~16.1 kcal/mol) values and large negative ΔS ‡ (�17.2~�20.0 cal/mol·K) values.