Application of Grunwald–Winstein correlation analyses with YBnBr scales to the solvolysis of benzoyl bromides

The solvolysis of 4-methoxy-(1), 4-methyl-(2), unsubstituted (3) and 4-chloro-(4) benzoyl bromide in a variety of solvents was studied. The linear log k–YBnBr plots for 1 indicates limiting SN1 mechanism, whereas the splitting of lines for nucleophilic solvents and poorly nucleophilic solvents in the case of 2 suggests significant nucleophilic solvent participation. The mechanism for the solvolysis of 3 and 4 probably varies with solvents, similar to that of the corresponding chlorides. Good linear Hammett log k–σ+ plot could be found in a few solvents. A comparison of the solvolytic behavior for aromatic acyl bromides and chlorides will be discussed.