PARTITIONING OF ALKYLPHENOLS AND ALKYLPHENOL POLYETHOXYLATES BETWEEN WATER AND ORGANIC-SOLVENTS

Partition coefficients of octylphenol (OP), nonylphenol (NP) and nonyl phenol ethoxylates (NPnEO, n=1-3) were determined for n-octanol/water and n-hexane/water systems. In the octanol/water system, logarithmic v alues of the partition coefficients (log K(ow)) for the phenols were 4 .12 and 4.48 for OP and NP, respectively. Slightly lower lipophilicity -was found for APnEO with log K(ow) values of NP1EO, NP2EO and NP3EO a round 4.2. The corresponding values in hexane/water system were approx imately 0.8 logarithmic units lower but showed essentially the same ra tio between NP and NPnEO as it was observed in the octanol water syste m. An attempt was made to estimate octanol/water partition coefficient s for higher OPnEO and NPnEO oligomers. Application of reversed-phase HPLC for this purpose resulted in a significant overestimation. Altern atively, octanol/water partition coefficients for the higher APnEO oli gomers were estimated (i) using an equation that correlates log K(ow) with solubility and (ii) converting the respective iso-octane/water pa rtition coefficients to the octanol/water coefficients.