SPECTROPHOTOMETRIC DETERMINATION OF ANIONIC MICELLAR BINDING CONSTANTS OF IONIZED AND NON-IONIZED PHENYL AND METHYL SALICYLATES

摘要

The ionized (S~-) and non-ionized (SH) phenyl (PSH) and methyl (MSH) salicylates exhibit strong and undetectable absorption at 350 nm, respectively. These molecular absorption properties were used to determine the binding constants of S~- and SH with the micelles of sodium dodecyl sulphate in terms of the pseudophase model of micelles. The binding constants (K_1)of S~- are 4.0±2.0 dm~3 mol~(-1) for PSH and 5.7±1.2 dm~3 mol~(-1) for MSH and those (K_2) of SH are 2350±90 dm~3 mol~(-1) for PSH and 100±10 dm~3 mol~(-1) for MSH at 30℃.