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Diss Factsheets
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EC number: 278-947-6 | CAS number: 78560-45-9
- 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
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Water solubility
Administrative data
Link to relevant study record(s)
- Endpoint:
- water solubility
- Data waiving:
- study scientifically not necessary / other information available
- Justification for data waiving:
- the study does not need to be conducted because the substance is hydrolytically unstable at pH 4, 7 and 9 (half-life less than 12 hours)
Reference
Description of key information
Water solubility [2-(perfluorohexyl)ethyl]trichlorosilane]: not relevant
Water solubility [2-(perfluorohexyl)ethyl]silanetriol]: 0.58 mg/l at 20°C (QSAR)
Key value for chemical safety assessment
Additional information
The requirement to conduct a water solubility study for the submission substance is waived on the basis that it hydrolyses very rapidly to [2-(perfluorohexyl)ethyl]silanetriol and hydrochloric acid. In accordance with ECHA decision number CCH-2120771164-56-01/F, a hydrolysis study is contracted with the registered substance. If the substance is demonstrated to decompose rapidly in contact with water, the water solubility endpoint can be waived in accordance with Column 2 of REACH Annex VII. Should this not be the case, a water solubility study according to OECD TG 105 will be attempted. The endpoint will be updated when the result of the hydrolysis study is available.
The silanol hydrolysis product, [2-(perfluorohexyl)ethyl]silanetriol, may undergo condensation reactions in solution to give siloxane dimers, linear and cyclic oligomers and highly cross-linked polymeric particles (sol) that may over time form an insoluble gel and a dynamic equilibrium is established. The overall rate and extent of condensation is dependent on nominal loading, temperature and pH of the system, as well as what else is present in the solution. This condensation may limit the saturation concentration in water below the estimated solubility of the silanetriol monomer. Further information is given in a supporting report (PFA 2016am) attached to Section 13.
The hydrolysis product, [2-(perfluorohexyl)ethyl]silanetriol, is slightly soluble in water based on a solubility of 0.58 mg/l calculated using a QSAR method. This QSAR method for water solubility cannot be validated for silanetriols because the saturation concentration of silanetriols in water is often limited by condensation reactions rather than lack of true solubility. The prediction is however considered to be valid for use in environmental exposure modelling and toxicokinetics modelling because it is considered to adequately describe the hydrophobicity of the substance and hence the partitioning behaviour.
The chemical structure contains a perfluorohexyl chain; fluorocarbons have very low solubility in water, relative to hydrocarbons of equivalent chain length (e.g. Horvath 1982), so it would be expected that a substance with this functional group would be of low solubility. The effective limits of solubility of both the parent substance and monomeric silanol hydrolysis products are very low. Condensation phenomena may limit the extent of hydrolysis under conditions at which the solubility of either parent or oligomer is exceeded. The predicted hydrolysis rates relate to dilute conditions. These factors are important in any consideration of aqueous behaviour and properties.
References:
Horvath A L (1982). Halogenated hydrocarbons: solubility-miscibility with water. CRC Press 26 February 1982.
PFA (2016am). Peter Fisk Associates, Silanols and aquatic systems, 404.105.003
Information on Registered Substances comes from registration dossiers which have been assigned a registration number. The assignment of a registration number does however not guarantee that the information in the dossier is correct or that the dossier is compliant with Regulation (EC) No 1907/2006 (the REACH Regulation). This information has not been reviewed or verified by the Agency or any other authority. The content is subject to change without prior notice.
Reproduction or further distribution of this information may be subject to copyright protection. Use of the information without obtaining the permission from the owner(s) of the respective information might violate the rights of the owner.
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