Kinetics of the basic hydrolysis of tris(1,10-phenenthroline)Fe(II): Influence of polymer–surfactant interactions

The kinetics of basic hydrolysis of tris(1,10-phenanthroline)iron(II) has been carried out in non-ionic polymer, poly(ethylene glycol) (PEG) and surfactant (anionic, cationic and non-ionic) mixtures using UV–vis spectroscopy system at 298 K. All types of surfactants, anionic (SDS), cationic (CTAB) and non-ionic (Triton X 100, Tween 20, Brij 35) have undergone interaction with the polymer. The polymer chain length with varying relative molecular mass from 200 to 600 has an effect on interaction. The observed pseudo-first order rate constants in the (PEG/surfactant/water) system increase gradually with polymer concentration. The conductometric and viscometric measurements also reveals the polymer–surfactant interactions. Experimental consequences reveal that the catalytic effects forced by the polymer–surfactant mixed systems cause significant influence on the kinetic properties of the reaction. Mainly surface catalysis is observed in polymer–cationic surfactant (CTAB) systems through adsorption of the reacting species on the micellar surface as both the reactants being ionic.

Non-ionic polymer poly(ethylene glycol), PEG and surfactant (cationic, anionic and non-ionic) interaction influences the rate of basic hydrolysis of tris(1,10-phenenthroline)Fe(II). The interaction between all types of surfactants and non-ionic polymers is mainly dominated by hydrophobic interaction over the coulombic interaction.Figure optionsDownload as PowerPoint slideHighlights
► Polymer facilitates smaller size of micelles and lowers CMC value of surfactant.
► The cationic and neutral surfactant–polymer systems catalyses the reaction rate.
► Coulombic and hydrophobic interactions contribute catalytic effect on rate.
► Catalytic effect of mixture on rate is related to the formation of many micelles.