Effect of cosolvents in the presence of sodium dodecyl sulfate micelles on the rate of alkaline hydrolysis of tris(2,2′-bipyridine)iron(II) complex

The kinetics of alkaline hydrolysis of tris(2,2′-bipyridine)iron(II) complex have been studied in the presence of various alcohols of different chain lengths and number of OH groups in aqueous and SDS micellar medium. In aqueous medium, rate increases at all percentages of 1-alkanols in the following order: PrOH > EtOH > MeOH > H2O, whereas the effectiveness of glycols as inhibitors is in the following order: Gly > EG > PG > H2O. Hence PrOH has the most pronounced effect as accelerator and Gly as inhibitor on rate. In the presence of SDS micelles, rate has been inhibited because of binding of SDS with substrate, but the presence of alcohols reduces this inhibitory effect of SDS. All these results have been explained in terms of the CMC, micellar size and properties of SDS in these cosolvents, H-bonding capacity of solvents, dielectric constants of the media, etc.