Kinetics and mechanism of oxidation of aspirin by bromamine-T, N-bromosuccinimide, and N-bromophthalimide

✍ Scribed by R. Ramachandrappa; Puttaswamy; S. M. Mayanna; N. M. Made Gowda

• Publisher: John Wiley and Sons
• Year: 1998
• Tongue: English
• Weight: 202 KB
• Volume: 30
• Category: Article
• ISSN: 0538-8066
• DOI: 10.1002/(sici)1097-4601(1998)30:6<407::aid-kin2>3.0.co;2-w

✦ Synopsis

The kinetics of the oxidation of aspirin (ASP) by bromamine-T (BAT), N-bromosuccinimide (NBS), and N-bromophthalimide (NBP) has been studied in aqueous perchloric acid at

The oxidation reaction follows identical kinetics with first-order in [oxidant], 303 K. fractional-order in [ASP], and inverse fractional-order in [H ϩ ]. Under identical experimental conditions the extent of oxidation with different oxidizing agents is in the order: NBS Ͼ

The rate decreased with decreasing dielectric constant of the medium. The vari-BAT Ͼ NBP. ation of ionic strength and the addition of the reaction products and halide ions had no significant effect on the reaction rate. The solvent isotope effect was studied using D 2 O. Kinetic parameters were evaluated by studying the reaction at different temperatures. The reaction products were identified by GC-MS. The proposed reaction mechanism and the derived rate law are consistent with the observed kinetic data. Formation and decomposition constants for ASP-oxidant complexes have been evaluated. Decarboxylation, bromination, and loss of acetic acid gave 2,4,6-tribromophenol.