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Diss Factsheets

Environmental fate & pathways

Other distribution data

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Administrative data

Endpoint:
other distribution data
Type of information:
experimental study
Adequacy of study:
key study
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
study well documented, meets generally accepted scientific principles, acceptable for assessment

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2011
Report date:
2011

Materials and methods

Test guideline
Qualifier:
no guideline followed
Principles of method if other than guideline:
- Principle of test: The objective was to derermine the distribution of Dimethylsilanediol (DMSD) in air, water, octanol systems and the dependence of these distributions from temperature. Therefore a three phase system (air, octanol, water) was used. The Kaw, Kow and Koa were determined.
- Short description of test conditions: A 100 mL borosilicate glass syringe was used in which a three phase system of air, octanol and water was established for the experiments. The experiment was conducted in an incubator in which the temperature was controlled.
- Parameters analysed / observed: The distribution/concentration of the substance between the three phases was measured via reversed phase HPLC/RAM, Normal phase HPLC/RAM and LSC Analysis.
GLP compliance:
no
Type of study:
other: Distribution of DMSD in a three phase system octanol - air - water system
Media:
other: air - octanol - water

Test material

1
Chemical structure
Reference substance name:
Dimethylsilanediol
EC Number:
213-915-7
EC Name:
Dimethylsilanediol
Cas Number:
1066-42-8
Molecular formula:
C2H8O2Si
IUPAC Name:
Dimethylsilanediol

Results and discussion

Any other information on results incl. tables

- The reversed phase HPLC chromatogram of DMSD-containing water showed small fraction (2 -5%) of dimer diol in the three phase equilibrium.

- Normal phase HPLC chromatograms of the 1-octanol from the three-phase equilibrium clearly indicated the existence of dimer diol, trimer diol and up to 6 compounds with shorter retention times than DMSD, especially for 35 °C.

- In previeous study equilibrium was found to be reached within 2 h if the equilibration started from DMSD containing water at 20 °C (Xu and Kropscott, 2011). The shortest time for all experiments was close to 20 h but no obvious deviation from their corresponding average values was observed.

- Overall, the values of log Kaw, log Koa and log Kow were relatively constant over time at each temperature.

- The measured partition coefficients were, obtained from a three-phase equilibrium state.

When the average values of three partition coefficients at four temperatures were plotted against the reciprocal of the equilibrium temperature, three linear correlations were obtained as follows:

log Kaw= -19.70 + 3739.5/T R2= 0.974 (n = 4)

log Koa= 21.34 - 4328.9/T R2= 0.980 (n = 4)

log Kow= 1.67 - 604.2/T R2= 0.988 (n = 4)

Based on these equations the partition coefficients for 25 °C were:

- log Kaw = -7.16,

- log Koa = 6.82,

- log Kow = -0.36

Measured values of partition coefficients in the current study are consistent with the log Kaw value measured at 35 °C using a syringe system containing water/air phases only (Xu and Kropscott, 2011).

Reference: Xu, S. and Kropscott, B. 2011. A Method for Determining Environmental Partition Coefficients of Dimethylsilanediol under Various Conditions.

Applicant's summary and conclusion

Conclusions:
The study determined the distribution of Dimethylsilanediol (DMSD) in a three phase system (air, water, octanol). The partition coefficients for 25 °C were log Kaw = -7.16, log Koa = 6.82 and log Kow = -0.36 in the three phase system.