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Partition coefficient

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Description of key information

A experimental study was conducted to determinate the partition coefficient Butnaol/water Kbw.


 


According to publication Estimating n-octanol-water partition coefficients for neutral highly hydrophobic chemicals using measured n-butanol-water partition coefficients, a relationship has been established between KBW and KOW: "Another approach is to use extrathermodynamic relationships (linear free-energy relationships) (Wold, 1974; Leffler and Grunwald, 2013) between partition coefficients in different solvents. Collander (1951) demonstrated that relationships of the form: log Ksolvent1/water = A + B Ksolvent2/water (1) exists for numerous solvent pairs where Ksolvent-1/water and Ksolvent-2/water are solvent-1/water and solvent-2/water equilibrium partition coefficients for organic chemicals."


 


Using the following equation, the KOW was calculated from the KBW: "The log KBWs for 29 chemicals were measured using the OECD slow stir technique (Tables 1 and 2). Among these chemicals, literature KBW values were available for benzene and chloroben- zene (Westall, 1983; Hansch et al., 1995, Table 1) and these agreed closely with our measurements (Table 1). The collected log KBWs from this study only and their available log KOWs data are shown in Fig. 2. The data are plotted with the following regression equation:


 


log KOW = 1.7769 (± 0.0560) log KBW - 1.5158 (±0.2365)


r2 = 0.978 ; n = 25"


 


Calculation detail


Log KBW = 0.93 (experimental study)


log KOW = 1.7769 x 0.93 - 1.5158 = 0.1367 --> KOW = 1.3699


log KOW = (1.7769 - 0.0560) x 0.93 - (1.5158 - 0.2365) = 0.3211 --> KOW = 2.0946


log KOW = (1.7769 + 0.0560) x 0.93 - (1.5158 + 0.2365) = - 0.0477 --> KOW = 0.8960


0.8960 < KOW < 2.0946


KOW = ca. 1.3699

Key value for chemical safety assessment

Log Kow (Log Pow):
0.14

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