Registration Dossier
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EC number: 209-136-7 | CAS number: 556-67-2 D4
- 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:
- 1 (reliable without restriction)
- Rationale for reliability incl. deficiencies:
- guideline study
- Qualifier:
- according to
- Guideline:
- OECD Guideline 123 (Partition Coefficient (1-Octanol / Water), Slow-Stirring Method)
- GLP compliance:
- yes
- Type of method:
- slow-stirring method
- Partition coefficient type:
- octanol-water
- Key result
- Type:
- log Pow
- Partition coefficient:
- 6.488
- Temp.:
- 25.1 °C
- Remarks on result:
- other: No pH stated
- Details on results:
- 6.488 ± 0.017 (1SD, n=3)
- Conclusions:
- A partition coefficient value of 6.49 was determined at 25.1°C in a reliable study conducted according to an appropriate test protocol, and in compliance with GLP.
Reference
Results for test vessel A
Sampling Time, h | Average Concentration D4(oct),μg/ml | Replicate Difference D4(oct),μg/mL | Average Concentration D4(aq), ng/mL | Replicate difference D4(aq), ng/mL | Log Kow |
24.3 | 393.5 | 4.6 | 0.1348 | 0.0077 | 6.4654 |
29.3 | 390.5 | 0.1 | 0.1209 | 0.0048 | 6.5093 |
48.2 | 390.7 | 0.5 | 0.1227 | 0.0015 | 6.5029 |
53.3 | 392.3 | 0.4 | 0.1375 | 0.0036 | 6.4553 |
71.9 | 389.1 | 2.1 | 0.1308 | 0.0106 | 6.4736 |
Average | 391.2 | 0.1293 |
| 6.4813 | |
Std Dev | 1.7 | 1.6 | 0.0073 | 0.0046 | 0.0237 |
Results for test vessel B
Sampling Time, h | Average Concentration D4(oct),μg/ml | Replicate Difference D4(oct),μg/mL | Average Concentration D4(aq), ng/mL | Replicate difference D4(aq), ng/mL | Log Kow |
24.9 | 393.8 | 0.6 | 0.1211 | 0.0072 | 6.5120 |
30.0 | 392.4 | 0.5 | 0.1259 | 0.0084 | 6.4936 |
48.8 | 391.9 | 1.9 | 0.1225 | 0.0012 | 6.5050 |
54.0 | 395.1 | 8.3 | 0.1316 | 0.0116 | 6.4776 |
72.7 | 386.3 | 6.4 | 0.1278 | 0.0041 | 6.4805 |
Average | 391.9 | 0.1258 |
| 6.4938 | |
Std Dev | 3.4 | 3.4 | 0.0042 | 0.0053 | 0.0150 |
Results for test vessel C
Sampling Time, h | Average Concentration D4(oct),μg/ml | Replicate Difference D4(oct),μg/mL | Average Concentration D4(aq), ng/mL | Replicate difference D4(aq), ng/mL | Log Kow |
25.6 | 395.5 | 1.9 | 0.1247 | 0.0013 | 6.5011 |
30.7 | 394.9 | 0.9 | 0.1315 | 0.0083 | 6.4776 |
49.5 | 395.1 | 0.3 | 0.1278 | 0.0023 | 6.4901 |
54.7 | 394.1 | 1.7 | 0.1301 | 0.0054 | 6.4812 |
73.5 | 394.5 | 1.8 | 0.1261 | 0.0006 | 6.4952 |
Average | 394.8 | 0.1281 |
| 6.4891 | |
Std Dev | 0.5 | 1.0 | 0.0028 | 0.0033 | 0.0097 |
Description of key information
log Kow [octamethylcyclotetrasiloxane]: 6.49 at 25.1°C (OECD 123) log Koa [octamethylcyclotetrasiloxane]: 4.22 at 24°C
Key value for chemical safety assessment
- Log Kow (Log Pow):
- 6.49
- at the temperature of:
- 25.1 °C
Additional information
Two reliable studies are available for the n-octanol-water partition coefficient of the substance. A measured log Kow of 6.49 at 25.1°C was determined for the substance in accordance with OECD 123, slow-stirring method. The result is considered to be reliable and selected as key study. This value is supported by another measured log Kow of 6.98 at 21.7°C using a syringe method.
A log Kow value of 5.1 was also determined for the substance using the HPLC method, however, this method is considered unsuitable for silicon-type substances as such was disregarded. In a secondary source to which reliability could not be assigned, log Kow value of 5.1 was reported for the substance.
A log Koa value of 4.22 at 24°C was determined for the substance in a reliable study conducted according to scientifically sound method and in compliance with GLP.
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