Metal–ligand complex formation in the presence of micelles. Part 2.—Kinetics of the reaction between copper (II) and 1-phenylbutane-1,3-dione (benzoylacetone) in the presence of non-ionic micelles of polyoxyethylene n-dodecyl ether

Abstract

The kinetics of the metal–ligand complexation reaction between Cu^II and the hydrophobic chelating agent, 1-phenylbutane-1,3-dione (benzoylacetone), have been studied in a non-ionic micellar solution of polyoxyethylene n-dodecyl ether by use of a stopped-flow apparatus.

Two relaxation curves with different relaxation times were observed. The fast relaxation curve was due to the reactions between the enol form of benzoylacetone and Cu^II in both aqueous and micellar phases. The overall rate constants in the micellar phase were ca. one order of magnitude lower than those in the aqueous phase. The slow relaxation curves was due to the reaction between the keto form and Cu^II in the aqueous phase. The rate constant was independent of the micellar concentration and the length of ethyliene oxide chain.