Kinetics and mechanism of intramolecular Carboxylic Acid participation in the hydrolysis of N-Methoxyphthalamic Acid

• Main Authors: Ariffin, Azhar, Khan, M.N.
• Format: Article
• Language: English
• Published: 2003
• Subjects: QD Chemistry
• Online Access: http://eprints.um.edu.my/8040/1/Khan-2003-Kinetics_and_mechani.pdf; http://eprints.um.edu.my/8040/; http://pubs.rsc.org/en/content/articlepdf/2003/ob/b300662j

The rate of formation and disappearance of phthalic anhydride (PAn) intermediate in the aqueous cleavage of N-methoxyphthalamic acid (NMPA) under acidic pH was studied spectrophotometrically in mixed CH3CN-H2O solvents. The rate of formation of PAn from NMPA is almost independent of the change in acetonitrile content from 20 to 70% v/v in mixed aqueous solvents. The rate constants for the formation of PAn from NMPA are similar to10-fold smaller than the corresponding rate constants for the formation of PAn from o-carboxybenzohydroxamic acid (OCBA). These observations are ascribed to the consequence of the occurrence of slightly different mechanisms in these reactions.