5735-66-0

The kinetics and mechanism of oxidation of amoxicillin by hexacyanoferrate(III) in aqueous alkaline medium at constant ionic strength of 0.10 mol dm-3 is studied spectrophotometrically at 25 °C. The reaction exhibits 2:1 ([Fe(CN)6]3-: amoxicillin) stoichiometry. The reaction products have been identified with the help of TLC and characterized by FT-IR, GCMS and LCMS. The reaction is first order in hexacyanoferrate(III) concentration but fractional order in both amoxicillin and alkali concentrations. The effects of ionic strength and dielectric constant have been investigated. In a composite equilibrium step, amoxicillin binds to hexacyanoferrate(III) to form a complex that subsequently decomposes to the products. Based on investigation of the reaction at different temperatures, computation of the activation parameters with respect to the slow step of the proposed mechanism was evaluated.

Flames from town gas-oxygen, hydrogen-oxygen, and ethylene-oxygen mixtures, when blown against the surface of an aqueous solution of amines and amino acids, induced an oxidation reaction in the aqueous phase, while an acetylene-oxygen flame failed to oxidize the compounds in solution. The hydrogen flame caused direct hydroxylation of the aromatic rings of phenylglycine homologs. The isomeric ratio of o-, m-, and p-hydroxyphenyl- amino acids produced was in accordance with that obtained by using the reaction systems of Fe2+-H2O2-EDTA and Fe2+-ascorbic acid-H2O2-EDTA, which are known to involve a hydroxyl radical as the agent for hydroxylating the aromatic rings. These results strongly suggest that the active species of flame-induced oxidation in an aqueous solution was the hydroxyl radical which was produced in the flames and extracted into the aqueous phase.

When argon-nitrogen plasma was blown into an aqueous solution containing aliphatic carboxylic acids, formation of several amino acids and amines was identified.

It was found that Argon arc plasma induced a powerful and clean stepwise oxidation reaction in aqueous solution containing various amino acids without using any oxidizing agent.