Kinetics and Mechanism of Oxidation of Carbenicillin by Copper (III) Periodate Complex in Aqueous Alkaline Medium

Abstract

Kinetics and mechanism of oxidation of carbenicillin by diperiodatocuprate [DPC-III] in aqueous alkaline medium were studied spectrophotometrically at 298 K and an ionic strength of 0.10 mol·dm−3. The reaction between DPC (III) and carbenicillin in the alkaline medium showed (CRBC : DPC-III) 1 : 4 stoichiometry. The reaction products were identified by the CHNS test, FT-IR, and LC-MS spectral reports. The reaction was of pseudo-first order with respect to DPC (III) and fractional order with respect to carbenicillin as well as alkali but retarding effect with respect to periodate. Monoperiodatocuprate (MPC-III) was found to be the main active species in the alkaline medium in the form of [Cu (H2IO6) (H2O)2]. Activation and thermodynamic parameters with respect to uncatalyzed rate constants (ku) and slow step rate constant (k) as well as equilibrium constants were determined. The plausible mechanism consistent with experimental results was proposed and discussed in detail.

Kinetics of Catalytic Oxidation of Carbenicillin: A Degradation Approach for Penicillanic Acid Derivatives (PADs)

“…The catalyzed reaction between CRBC and DPC (III) in an aqueous alkaline medium [29] can be presented by:…”

“…With variable concentration of CRBC, CoCl 3 , KIO 4 , KOH, and constant concentration of DPC (III), reaction orders were obtained from the slopes of log (absorbance) vs. time, independently for each concentration of DPC (III) [29].…”

“…The kinetics of uncatalyzed oxidation of Carbenicillin by DPC (III) has been investigated experimentally [29]. As a result, the primary goal is to investigate the kinetics of carbenicillin oxidation and to anticipate a likely process while also determining activation and thermodynamic parameters.…”