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Diss Factsheets
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EC number: 257-473-3 | CAS number: 51851-37-7
- 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
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Endpoint summary
Administrative data
Description of key information
- Concentration of the silanol; the greater the initial concentration, the greater the degree of condensation. Significant condensation is not expected at concentrations less than approximately 100 mg/l, but is dependent on specific conditions.
- pH; the condensation reaction may be either acid or base catalysed.
- Temperature.
- Other species present.
- The nature of the R group
- Timescale
- The number of Si-OH groups; silanetriols condense more rapidly than silanediols
[2-(Perfluorohexyl)ethyl]triethoxysilane is a liquid at standard temperature and pressure, with a measured melting point of <-100°C, and a measured boiling point of 225°C at 1007 hPa. It has a measured relative density of 1.3417 at 20°C and a predicted vapour pressure of 9.8 Pa at 25°C.
The registration substance has a predicted log Kow value of 7.2 at 20°C and a measured water solubility limit of <2 mg/L at 20°C and pH 6.29. The predicted water solubility of [2-(perfluorohexyl)ethyl]triethoxysilane is 6.4E-06 mg/L at 20°C. A surface tension value of 72.2 mN/m at 20°C and 10 mg/L was obtained for the substance.
The substance is not classified for flammability according to Regulation (EC) No. 1272/2008 on the basis of a measured flash point of 108.5°C at 1013 hPa. It has a measured auto-ignition temperature of 245°C at 1003-1017 hPa and is not explosive and not oxidising on the basis of chemical structure.
In contact with water under dilute conditions, [2-(perfluorohexyl)ethyl]triethoxysilane reacts moderately rapidly (half-life of 12.5 hours at pH 7, 1.44 hours at pH 4, 5.18 hours at pH 9, and at 20°C) to produce [2-(perfluorohexyl)ethyl]silanetriol and ethanol according to the following equation:
C14H19F13O3Si + 3H2O → C8H7F13O3Si + 3C2H5OH
Silanetriols may undergo condensation reactions to give siloxane dimers, oligomers and polymers, according to the scheme:
RSi(OH)3 ⇌ RSi(OH)2OSi(OH)2R ⇌ RSi(OH)2O[Si(R)(OH)O]nSi(OH)2R
(where R is an alkyl or aryl side-chain)
A highly cross-linked gel may form. The degree of condensation that will occur may vary with:
In the case of this substance the R group 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 R group would be of low solubility; the corresponding monomeric silanetriol is expected to be surface active based on measured and read across data. The presence of fluorocarbon chains may mean that condensation products could have some surface activity. For these reasons, the effective limits of solubility of both the parent substance and monomeric silanol hydrolysis products are very low and all forms of the substance may have a tendency to enrich at surfaces rather than forming stable dispersions in solution. These phenomena may limit the extent of hydrolysis under conditions at which the solubility of either parent or oligomer is exceeded. The measured rates presented above relate to dilute conditions. These factors are important in any consideration of aqueous behaviour and properties.
Ethanol is miscible with water, has low log Kow (-0.3) and high vapour pressure (7910 Pa at 25°C).
The silanol hydrolysis product, [2-(perfluorohexyl)ethyl]silanetriol has a predicted water solubility of 0.58 mg/l at 20°C and a predicted log Kow of 2.8 at 20°C. It is considered to be surface active based on a measured surface tension value of <22 mN/m at 20°C and 1 g/l. [2-(Perfluorohexyl)ethyl]silanetriol is much less volatile than the parent substance (vapour pressure of 6.9E-03 Pa at 25°C, predicted).
Reference:
Horvath, A.L (1982). Halogenated hydrocarbons: solubility-Miscibility with water. CRC press 26 Feb 1982
Additional information
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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