Some Kinetic Studies in the Reversed Micellar System-Aerosol OT (Diisooctyl Sulfosuccinate)/H2O/Heptane Solution

Abstract

From 1H and 23Na NMR studies, the water molecules partitioning into the hydration shell of the counter ions are found to be highly immobilized in the reversed micelles Aerosol OT/H2O/Heptane. Upon the completion of hydration shell, ttie mobility of water is enhanced and approaches that of the ordinary water. Fluorescent probes Pyrene (Py) and Pyrene Sulfonic Acid (PSA) are incubated into the reversed micelles and excited by the pulsed ruby Laser 347.1 nm light. The subsequent decay of the excited singlet states of the probes were followed to study the dynamic motions of the probe and the added quenchers. For the ionic quenchers, the motion is very restricted at low water content. On the other hand, O2 and CH2I2 can undergo unrestricted diffusion. The quenching constants are lower forthe hydrophobic probe Py than the amphiphillic probe PSA in the case of ionic quenchers which is attributed to the larger encountered probability between the quencher and PSA. Nanosecond pulsed radiolysis of biphenyl in the reversed micelles leads to the formation of biphenyl anion and triplet.