AQUEOUS SOLUBILITY OF ALKYLPHENOLS AND ALKYLPHENOL POLYETHOXYLATES

Aqueous solubilities of nonylphenol (NP), octylphenol (OP) and their e thylene oxide adducts with 1-5 ethoxy groups were determined using a g enerator column technique followed by subsequent off-line HPLC analysi s of the aqueous solutions. The solubilities of OPnEO oligomers (8.0-2 4.5 mg/L) were significantly greater than those of the corresponding N PnEO oligomers (3.02-9.48 mg/L) indicating a predominant influence of the hydrophobic chain length on APnEO solubility. A linear relationshi p between solubility and the number of EO groups was established for b oth oligomer series. However, nonethoxylated alkylphenols showed irreg ularly enhanced solubilities as compared to the corresponding ethoxyla ted compounds probably caused by different impacts of phenolic and alc oholic OH functional groups. NP and NP1EO showed a gradual solubility increase towards higher temperatures in the temperature range examined (2-25-degrees-C), while an irregular behaviour was observed for NP2EO . The concentrations of individual oligomers in solutions of APnEO oli gomer mixtures were below their saturation levels, while the oligomer composition in the solution showed significant change compared with th e original one, reflecting different solubilities of the individual ol igomers as pure substances.