Kinetics of the Oxidation of Tetracycline Hydrate by Copper(II) Complexed with Bipyridyl in Alkaline Medium Using Chloro-Complex of Palladium(II) As Homogeneous Catalyst

• Published in: Industrial & engineering chemistry research 2012-04, Vol.51 (16), p.5728-5736
• Main Authors: Singh, Ashok Kumar, Singh, Manjula, Rahmani, Shahla, Srivastava, Jaya, Singh, Jagdamba
• Format: Article
• Language: English
• Subjects: Activation analysis; Activation entropy; Applied sciences; Catalysis; Catalytic reactions; Chemical engineering; Chemistry; Entropy of activation; Exact sciences and technology; General and physical chemistry; Hydrates; Mathematical analysis; Oxidation; Reaction kinetics; Reactors; Tetracyclines; Theory of reactions, general kinetics. Catalysis. Nomenclature, chemical documentation, computer chemistry
• ISSN: 0888-5885; 1520-5045
• DOI: 10.1021/ie300306a

The present paper deals with the kinetics and mechanism of Pd­(II)-catalyzed oxidation of tetracycline hydrate by Cu­(Bip)2 2+ in alkaline medium. First-order kinetics with respect to [tetracycline hydrate] and fractional positive order kinetics in [Cu­(II)] and [Pd­(II)] was observed. Nil effect of [OH–] and [bipyridyl] on the rate of oxidation was observed. Almost no effect of ionic strength as well as dielectric constant of the medium on the rate of oxidation was observed. The reaction was studied at four different temperatures and observed values of rate constants were utilized to calculate various activation parameters specially the entropy of activation (ΔS #). With the help of the observed kinetic orders with respect to the reactants involved in the reaction, spectrophotometric evidence collected for the formation of reactive complexes and the positive entropy of activation, a most probable reaction mechanism for Pd­(II)-catalyzed oxidation of tetracycline hydrate by Cu­(Bip)2 2+ in alkaline medium has been proposed.