Effect of sodium dodecyl sulfate micelles on complex formation of-2nitroso-1-naphthol with iron (II)‎ ion in aqueous urea solutions

Abstract EN

-The effect of sodium dodecyl sulfate (SDS) micelles on the observed rate constant (kobs) for complex formation of 2-nitroso-1-naphthol (NAPH ) with iron (II) ion (Fe2+) in the presence of 0.02 M NaOH at 25oC was studied at different urea concentrations.

Typical saturation behavior was observed at [NAPH] ≥ 0.

001 M and [Fe2 + ] ≥ 0.

015 M, which allows the electron transfer rate constant (ketm ) between NAPH and Fe2+ in the micellar pseudophase to be evaluated.

The increase in urea concentrattion from 0.0 to 4.

0 M has three effects.

It increases ketm from 0.072 to 0.239 s-1, decreases the critical micelle concentration (cmc) from 6.

5 to 3.

5 mM and increases the NAPH binding constant to SDS micelles (K) from 20 to 170 M-1.

At constant SDS concentration, the complex formation constant (KIP) increases with increasing urea concentration.