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Diss Factsheets
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EC number: 203-497-4 | CAS number: 107-51-7
- 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)
Description of key information
Log Kow: 6.6 at 25.3°C (OECD 123)
Log Koa = 3.79± 0.01 at 20.8±0.4°C
Log Kaw = 3.04± 0.20 at 20.8±0.4°C
Key value for chemical safety assessment
- Log Kow (Log Pow):
- 6.6
- at the temperature of:
- 25.3 °C
Additional information
Three reliable measured n-octanol/water partition coefficient data are available for octamethyltrisiloxane. An n-octanol/water partition coefficient (log Kow) of 6.6 was determined using OECD 123 and in compliance with GLP. The result is considered to be reliable and selected as key study. Other reliable data reported log Kow values of 6.87 at 20.8°C and 6.6 at 24.1°C. In other secondary sources to which no reliability could be assigned, log Kow values of 4.8 at 25°C and 4.8 - 5.4 were reported for the substance. The study with the highest reliability was assigned as key study.
A disregarded log Kow of 4.6 at 22.3°C (Dow Corning Corporation, 2006) was also determined for the substance because the method used is reportedly associated with a possible under estimation of values of log Kow bearing in mind susceptibility to hydrolysis. The method used was the slow-stirring method with the analytical determination based on 14C-radiolabelled test substance. Liquid scintillation counting was used for the analysis of total radioactivity in each phase. The accuracy of the reported value rested on the assumption that the 14C radioactivity in the aqueous phase represented only 14C-test substance, which was not confirmed during the study. The much greater value of log Kow for the substance determined in the key study (Dow Corning Corporation, 2008) suggests that this assumption was invalid. This is most likely due to the presence of trace level impurities or degradation (radiolysis) products in the radiolabelled test material having lower Kow values than the parent compound.
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