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Partition coefficient

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partition coefficient
Type of information:
experimental study
Adequacy of study:
key study
Study period:
February 12, 1992
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
study well documented, meets generally accepted scientific principles, acceptable for assessment
according to guideline
other: Tanii and Hashimoto (1982)
Version / remarks:
Tanii, H. and Hashimoto, K. (1982). Structure-toxicity relationship of acrylates and methacrylates. Toxicology Letters, 11, 125 - 129.
Principles of method if other than guideline:
N-octanol was saturated with distilled water and distilled water was saturated with n-octanol. The test substance was dissolved in distilled water at <1.0 mM. Within sealed tubes the water and n-octanol organic phase were mixed at a volume ratio of 5 ml and 1.0 ml, respectively, before being placed on a mechanical shaker for 1 hour and centrifuged for 30 minutes at 2500 revolutions per minute. Gas-liquid chromatography (Hitachi Model 163 gas chromatograph with flame ionisation detector) was used to analyse the quantity of 2-(2-methylpropoxy)ethanol in the water phase. The temperature of the gas chromatography glass column and detector was 160 and 180 °C, respectively, and the carrier gas was N2. The column was packed with polyethylene glycol 20 M. The concentration of 2-(2-methylpropoxy)ethanol) in the water phase was used to determine that present inn-octanol. The following equation was used to calculate the partition coefficient for the registered substance:
P = Concentration of ester in-octanol / Concentration of ester in water
GLP compliance:
Type of method:
estimation method (solubility ratio)
Partition coefficient type:
Analytical method:
other: Gas-liquid chromatography (Hitachi Model 163)
Key result
log Pow
Partition coefficient:
Remarks on result:
other: Mean of three determinations / Undertaken at room temperature
Details on results:
2-(2-methylpropoxy)ethanol) was clearly seperated from the organic n-octanol phase that was dissolved in distilled water.
The octanol-water partition coefficient for 2-(2-methylpropoxy)ethanol was calculated to be log Kow = 0.75 following analyses by gas-liquid chromatography.
Executive summary:

An experiment was undertaken by Tanniet al. (1992) to determine the octanol-water partition coefficient of 2-(2-methylpropoxy)ethanol and thirteen other ethylene glycol ethers as part of a study evaluating structure-toxicity relationships. The estimation (solubility ratio) methodology followed was according to that outlined by Tanni and Hashimoto (1982) and involved analyses by gas-liquid chromatography with flame ionisation detection and a glass column. Under the conditions of the experiment, 2-(2-methylpropoxy)ethanol was reported to be evidently separated from the organic (n-octanol) phase that had been dissolved in water. Following analyses, a log Kow of 0.75 was determined for 2-(2-methylpropoxy)ethanol.

Description of key information

Following analyses by gas-liquid chromatography, a log Kow of 0.75 was determined for the partition coefficient of 2-(2-methylpropoxy)ethanol, i.e. the ratio of the concentrations of the registered substance present in water and an organic (n-octanol) phase.

Key value for chemical safety assessment

Log Kow (Log Pow):
at the temperature of:
20 °C

Additional information

The key value was obtained from a study that was considered to be well documented and have met generally accepted scientific principles. The result was published in a reputable scientific journal (Archives of Toxicology) and the procedure, although not guideline (e.g. OECD) or a national standard method, was published by Toxicology Letters (Tanni and Hashimoto 1982). A Klimisch score of 2 (reliable with restrictions) has subsequently been recommended for the endpoint value and it is suitable for chemical safety assessment.