OECD SIDS 2. PHYSICO-CHEMICAL DATA
ID: 79-50-5 DATE: 18.01.2006
ca. .102 hPa at 20 degree C
Year: GLP: Test substance:
other (calculated): extrapolated from measured values at 60, 100 and 260 °C 2004 no as prescribed by 1.1 - 1.4
The three measured values were entered into a SigmaPlot spreadsheet, based on which a log-log graph of temperature (K) vs pressure (hPa) was drawn. The SigmaPlot regression line has the equation: f(x) = x*b - b, where
b = b =
r ² = 0 . 9 9 9 7 1 1 3 0 9 1 Based on the equation parameters described in Methods, a vapour pressure of approximately 0.102 hPa was extrapolated .
a temperature of 20 °C. valid with restrictions
Rational but uncertainty.
2.5 Partition Coefficient
Partition Coeff.: octanol-water
log Pow: PH prec:
= -.69 at 21 degree C = 6.3 - 6.5
OECD Guide-line 107 Flask-shaking Method" 1999 yes
"Partition Coefficient (n-octanol/water),
Based on a preliminary calculation of the n-octanol/water
partition coefficient by the Rekker method, which resulted in a logKow of -0.02, the flask-shaking method OECD 107 was selected for the experimental determination of the logKow. The (acidic) pKa for dl-lactone was modelled by NOTOX to be 13.2, hence the water phase was not buffered for the test. According to the OECD 107 method, a stock solution was prepared by dissolving 64.6 mg dl-lactone in 25.0 ml double-distilled water that had been saturated with n-octanol (99% HPLC Grade, Sigma-Aldrich, USA). In order to dissolve the test substance, the solution was sonicated for for 5 min. Three tests were carried out at 21±0.5°C using different volumes of n-octanol and double-distilled water (mutually saturated). The volumetric ratios of water and octanol were 1:2, 1:1 and 2:1, respectively. For each test, duplicate vessels containing the required, accurately measured amounts of the two solvents and the stock solution were prepared and shaken by hand during 5 min. Phase separation was achieved by centrifugation for 5 min at 3500 g and 20°C. The pH of each aqueous phase was determined. For the preparation of a blank, a vessel containing equal amounts of octanol saturated with water and water saturated with octanolwas shaken, centrifuged and analysed similar to the test substance vessels.