Abstract
The effects of micellar structure on the oxidation of p-isopropyl benzaldehyde (PBA) in aqueous solutions of the nonionic surfactants were investigated. The micellar aggregation number was determined with a low-angle light-scattering photometer while the determination of micellar shape and volume were made by measuring viscosity.
The summary of the results is shown below.
1) The micellar aggregation number decreased with the increase in the oxyethylene chain length of the nonionic surfactants.
2) The micelle was spherical and the micellar volume remained approximately the same regardless of the oxyethylene chain length of the nonionic surfactants.
3) The binding site of PBA within micelles was the core of any of the nonionic surfactants.
4) The oxidation of PBA in the micellar system was inhibited with the increase in the oxyethylene chain length of the nonionic surfactants.
Since the micellar core having a few aggregation number had a few hydrocarbon chain, the hydrophobic bond between oxygen and hydrocarbon decreased. Consequently, it was presumed that the oxygen concentration of such micellar cores was low.
From these results, the oxidation of PBA was inhibited with the increase in the oxyethylene chain length of the nonionic surfactants, this reason was thought to be due to the solubilization of PBA in the core having a lower oxygen concentration.
