title: Kinetics of hydrolysis and cyclization of ethyl 2-(aminosulfonyl)benzoate to saccharin.
abstract: The cyclization of ethyl 2-(aminosulfonyl)benzoate (ASB) to give saccharin was investigated in aqueous solutions at pH between 5.2 and 9.5 and in the temperature range of 296.2-334.2 K. The initial concentration of the reactant was varied between 1.45 x 10(-5) and 3.86 x 10(-4) M. Ultraviolet spectroscopy was used to obtain the kinetic data. The reaction is acid catalyzed and follows pseudo-first-order kinetics. The experimental rate constant, k(obs), increases with temperature and pH. Its dependence on the temperature and pH is well described by: k(obs) = k1 [OH-] = [(2.52 +/- 0.9) x 10(16) exp(-20.2 +/- 1 kcalmol(-1)/RT) s(-1)][OH-] A mechanism is proposed and the half-life of ethyl ASB is calculated.
mesh_terms: D001565:Benzoates / Q000737:chemistry* / Q000378:metabolism; D002384:Catalysis; D003500:Cyclization; D006863:Hydrogen-Ion Concentration; D006868:Hydrolysis; D007700:Kinetics; D012439:Saccharin / Q000737:chemistry* / Q000378:metabolism; D013056:Spectrophotometry, Ultraviolet; D013449:Sulfonamides / Q000737:chemistry* / Q000378:metabolism; D013696:Temperature; D014874:Water Pollutants, Chemical / Q000378:metabolism
chemical_list: D001565:Benzoates; D013449:Sulfonamides; D014874:Water Pollutants, Chemical; C471072:ethyl 2-(aminosulfonyl)benzoate; D012439:Saccharin