SPECTROPHOTOMETRIC STUDY OF THE PROTONATION PROCESSES OF SOME N-(4-X-PHENYLAMINOMETHYL)-PHTHALIMIDE DERIVATIVES

The protonation of N-(4-X-phenylaminomethyl)-phthalimide derivatives a nd phthalimide in aqueous acidic (H2SO4) media was investigated, using the spectrophotometric method. These phthalimide derivatives have thr ee protonation processes. The first protonation process occurs in pH r ange and belongs to the protonation of amino-group. The second and the third protonation process (occur in concentrated sulfuric acid soluti ons) are overlapping processes. They were separated by the modified me thod of separation (Garcia et al.). The protonation constants were cal culated by Hammett and Cox-Yates method. The effect of chemical struct ure on ionisation constants is discussed.