Pseudo-first-order rate constants, kobs, for hydrolysis of N-(2'-methoxyphenyl)-phthalimide (1) show a nonlinear decrease with the increase in [HCl] over the range 5 × 10−3 - 1.0 M at 2.0 × 10−4 M 1, 1.0 M ionic strength (μ, by NaCl) and 35°C. White fluffy precipitates have been found to appear into the reaction mixtures under such conditions, not at reaction time t = 0 but during the course of reaction. Similar observations have been found at 3.0 × 10−4M 1. These rather unusual observations have been found to be due to a special NaCl salt effect on kobs.
