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EC number: 214-189-4 | CAS number: 1112-39-6
- Life Cycle description
- Uses advised against
- Endpoint summary
- Appearance / physical state / colour
- Melting point / freezing point
- Boiling point
- Density
- Particle size distribution (Granulometry)
- Vapour pressure
- Partition coefficient
- Water solubility
- Solubility in organic solvents / fat solubility
- Surface tension
- Flash point
- Auto flammability
- Flammability
- Explosiveness
- Oxidising properties
- Oxidation reduction potential
- Stability in organic solvents and identity of relevant degradation products
- Storage stability and reactivity towards container material
- Stability: thermal, sunlight, metals
- pH
- Dissociation constant
- Viscosity
- Additional physico-chemical information
- Additional physico-chemical properties of nanomaterials
- Nanomaterial agglomeration / aggregation
- Nanomaterial crystalline phase
- Nanomaterial crystallite and grain size
- Nanomaterial aspect ratio / shape
- Nanomaterial specific surface area
- Nanomaterial Zeta potential
- Nanomaterial surface chemistry
- Nanomaterial dustiness
- Nanomaterial porosity
- Nanomaterial pour density
- Nanomaterial photocatalytic activity
- Nanomaterial radical formation potential
- Nanomaterial catalytic activity
- Endpoint summary
- Stability
- Biodegradation
- Bioaccumulation
- Transport and distribution
- Environmental data
- Additional information on environmental fate and behaviour
- Ecotoxicological Summary
- Aquatic toxicity
- Endpoint summary
- Short-term toxicity to fish
- Long-term toxicity to fish
- Short-term toxicity to aquatic invertebrates
- Long-term toxicity to aquatic invertebrates
- Toxicity to aquatic algae and cyanobacteria
- Toxicity to aquatic plants other than algae
- Toxicity to microorganisms
- Endocrine disrupter testing in aquatic vertebrates – in vivo
- Toxicity to other aquatic organisms
- Sediment toxicity
- Terrestrial toxicity
- Biological effects monitoring
- Biotransformation and kinetics
- Additional ecotoxological information
- Toxicological Summary
- Toxicokinetics, metabolism and distribution
- Acute Toxicity
- Irritation / corrosion
- Sensitisation
- Repeated dose toxicity
- Genetic toxicity
- Carcinogenicity
- Toxicity to reproduction
- Specific investigations
- Exposure related observations in humans
- Toxic effects on livestock and pets
- Additional toxicological data
Partition coefficient
Administrative data
Link to relevant study record(s)
- Endpoint:
- partition coefficient
- Type of information:
- experimental study
- Adequacy of study:
- key study
- Reliability:
- 2 (reliable with restrictions)
- Rationale for reliability incl. deficiencies:
- comparable to guideline study with acceptable restrictions
- Guideline:
- other: Three Phase Equilibrium Method
- 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 method:
- HPLC method
- Remarks:
- with liquid scintillation counting (LSC)
- Partition coefficient type:
- octanol-water
- Analytical method:
- high-performance liquid chromatography
- Key result
- Partition coefficient:
- ca. 6.82
- Temp.:
- 25 °C
- Remarks on result:
- other: log Koa; extrapolated from log Koa at four temperatures, plotted against the 1/T
- Key result
- Partition coefficient:
- 6.58
- Temp.:
- 20.2 °C
- Remarks on result:
- other: log Koa ± 0.34; Temperature ± 0.3 °C
- Key result
- Partition coefficient:
- ca. -7.16
- Temp.:
- 25 °C
- Remarks on result:
- other: log Kaw; extrapolated from log Kaw at four temperatures, plotted against the 1/T
- Key result
- Partition coefficient:
- -6.94
- Temp.:
- 20.2 °C
- Remarks on result:
- other: log Kaw ± 0.33; Temperature ± 0.3 °C
- Key result
- Type:
- log Pow
- Partition coefficient:
- ca. -0.36
- Temp.:
- 25 °C
- Remarks on result:
- other: Extrapolated from log Kow at four temperatures, plotted against the 1/T
- Key result
- Type:
- log Pow
- Partition coefficient:
- -0.38
- Temp.:
- 20.2
- Remarks on result:
- other: log Pow ± 0.4; Temperature ± 0.3 °C
- 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.
- Endpoint:
- partition coefficient
- Type of information:
- experimental study
- Adequacy of study:
- supporting study
- Reliability:
- 2 (reliable with restrictions)
- Rationale for reliability incl. deficiencies:
- study well documented, meets generally accepted scientific principles, acceptable for assessment
- Qualifier:
- no guideline followed
- Principles of method if other than guideline:
- Principle of test:
The objective was to determine the distribution of volatile methyl siloxanes such as Dimethylsilanediol (DMSD) in air, water, octanol systems. 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. The experiments were conducted in an incubator at constant temperature.
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 method:
- other: Distribution of DMSD in a three phase system octanol - air - water system
- Partition coefficient type:
- other: air - octanol - water
- Type:
- log Pow
- Partition coefficient:
- -0.41
- Temp.:
- 20 °C
- Remarks on result:
- other: pH assumed to be neutral
- Conclusions:
- The study determined the distribution of Dimethylsilanediol (DMSD) in a three phase system (air, water, octanol).
A log Kaw = -6.84 ±0.34, log Koa = 6.41 ±0.31 and log Kow = -0.41 ±0.1 were determined for the three phase system. - Endpoint:
- partition coefficient
- Type of information:
- (Q)SAR
- Adequacy of study:
- supporting study
- Study period:
- 2022
- Reliability:
- 2 (reliable with restrictions)
- Rationale for reliability incl. deficiencies:
- results derived from a valid (Q)SAR model and falling into its applicability domain, with adequate and reliable documentation / justification
- Justification for type of information:
- See attached QMRF/QPRF
- Principles of method if other than guideline:
- The result was obtained using an appropriate QSAR method (see attached QMRF and QPRF for details).
The model is the publicly available KOWWIN v1.68 program (USEPA 2011). KOWWIN is part of EPI Suite v4.1 and may be downloaded from http://www.epa.gov/oppt/exposure/pubs/episuite.htm. The model is based on fragment values. That is, the chemical structure is broken down into its constituent functional groups, and the contribution of each group toward the overall partition coefficient is calculated. The constants used within KOWWIN have been derived by SRC from a wide range of organic chemicals. The authors of this QMRF have carried out additional validation and found the method to be applicable organosilicon compounds, excluding di- and tri-alkoxysilanes.
USEPA 2011. KOWWIN v. 1.68, US EPA. 2011. Estimation Programs Interface Suite™ for Microsoft® Windows, v 4.10. United States Environmental Protection Agency, Washington, DC, USA. Available at http://www.epa.gov/oppt/exposure/pubs/episuite.htm. - GLP compliance:
- no
- Partition coefficient type:
- octanol-water
- Type:
- log Pow
- Partition coefficient:
- -0.38
- Temp.:
- 20 °C
- Conclusions:
- A Log Kow of -0.4 was obtained for the hydrolysis product using an appropriate calculation method. The result is considered to be reliable.
Referenceopen allclose all
Results
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.
Table 1: Experimental Results for Room Temperature Partition Measurements Based on Three Phase Equilibration for DMSD.
No of replicates |
average temperature |
average concentration [mg/L] |
log Kaw |
log Koa |
log Kow |
δ |
||
|
|
octanol |
air |
water |
|
|
|
|
12 |
20.1 |
29 |
1.0E-05 |
70 |
-6.84 ±0.34 |
6.4 ±0.31 |
-0.41 ±0.1 |
0.03 |
δ = log Kow - log Kaw - log Koa
The minimum equilibrium time for dimethylsilanediol (DMSD) was between 2 and 20 h depending on whether the equilibrium was started with 14C-DMSD-containing water and DMSD-free 1-octanol phase or DMSD-free water (10 mL) and 14C-DMSD-containing 1-octanol (0.4 mL), respectively.
Using those equilibrium times, the average concentrations of DMSD in the three phases and subsequently the three partition coefficients (Kaw, Koa, Kow) of the three phase system were calculated.
The results show that the measured partition coefficients were obtained from the equilibrium states, not the steady states.
Estimated value, no data available for temperature and pH
Description of key information
Log Kow = -0.38 at 20.2°C (octanol/water/air three-phase equilibrium method)
Key value for chemical safety assessment
- Log Kow (Log Pow):
- -0.38
- at the temperature of:
- 20.2 °C
Additional information
The key study is supported by a Log Kow of -0.4 at pH 7 and 20°C, calculated using a valid QSAR method. An additional study provided a Log Kow value of -0.41, determined by the distribution in a three phase system (no guideline given).
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