Solubility of nonylphenol and nonylphenol ethoxylates. On the possible role of micelles

The water solubility of nonylphenol (NP) has been estimated to be 4.9 +/- 0 .4 mg/l corresponding to (2.22 +/- 0.18) x 10(-5) mol/l at 25 degreesC usin g shake flask and surface tension techniques. The low solubility in combina tion with an observed rather slow dissolution process will limit the leacha bility of NP in the terrestrial environment. Based on indirect evidence, it is suggested that NP, in contrast to nonylphenol ethoxylate (NPEO) with, e .g., 12 ethoxylate moieties, is not subject to micelle formation, and as su ch does not constitute a potential vehicle for the transport of hydrophobic pollutants in the environment. For NPEOs with a very high number of ethoxy moieties, e.g., 100, the compounds appear water soluble without micelle fo rmation. (C) 2001 Elsevier Science Ltd. All rights reserved.