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EC number: 240-914-9 | CAS number: 16881-77-9
- 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
Endpoint summary
Administrative data
Description of key information
Additional information
Dimethoxy(methyl)silane (CAS No. 16881-77-9) is characterized by a high water solubility of 1.7E+04 mg/L (QSAR), a vapour pressure of 7.1E03 Pa (QSAR) and a low log Kow of 1.4 (QSAR).
It is expected to undergo a rapid two-step hydrolysis under environmental conditions. In a first step, the parent substance hydrolyses to the silanol hydrolysis product methylsilanediol, which further hydrolyses to methylsilanetriol (CAS No. 2445-53-6) in a second step. The non-silanol hydrolysis product is methanol. The predicted half-life is 0.3 h at pH 7 (QSAR). However, a hydrolysis study according to OECD Guideline 111 is currently being conducted and the dossier will be updated once the final study report is available.
The ECHA guidance R.16 states that “for substances where hydrolytic DT50 is less than 12 h, environmental effects are likely to be attributed to the hydrolysis product rather than to the parent itself” (ECHA, 2016). The TGD (EC2003) and ECHA guidance R.16 (ECHA 2010) also suggests that in case the hydrolysis half-life is less than 12 h, the breakdown products, rather than the parent substance, should be evaluated for aquatic toxicity.
It is anticipated that the second silanol hydrolysis product methylsilanetriol is the final product of the hydrolysis reactions that rapidly occur under environmentally relevant conditions and is thus considered the relevant assessment entity for the present Chemical Safety Assessment according to REACH. Thus, the environmental fate assessment as well as the hazard and risk assessment are based on the hydrolysis products methylsilanetriol and methanol rather than the parent substance.
Methylsilanetriol (CAS No. 2445-53-6)
Methylsilanetriol is characterized by high water solubility (1.0E+06 mg/L, QSAR), low vapour pressure (0.05 Pa, QSAR) and a low partition coefficient (log Kow = -2.4). It has an estimated dissociation constant of about 10 (pKa), indicating that it will not undergo significant dissociation in the environmentally relevant pH range of 4 to 9. No significant biodegradation is expected but its potential for bioaccumulation is low.
Based on its physico-chemical properties, methylsilanetriol is expected to preferentially distribute to the aquatic compartment. Exposure of the sediment and soil compartments are expected to be low.
Methanol (CAS No. 67-57-1)
Methanol is well characterised in the public domain and has a low environmental hazard profile (OECD SIDS, 2004).
It is fully water miscible at ambient temperatures and does not undergo hydrolysis. Volatilization is not a significant removal process from the aquatic phase. It is readily biodegradable and is characterized by a low log Kow of -0.82 to -0.64 (measured). Therefore, bioaccumulation in fish is expected to be low.
The short- and long-term aquatic toxicity of methanol has been extensively studied for a broad spectrum of aquatic species and its toxicity to aquatic organisms is low (effect values > 1000 mg/L; OECD SIDS, 2004). Therefore, it is not hazardous at the concentrations relevant to the studies in this dossier and is not considered contributory to the overall aquatic toxicity profile of the registered substance.
Reference
OECD, 2004: SIDS Initial Assessment Report for Methanol, SIAM 19, Berlin, Germany, 19-22 October 2004, Methanol, CAS 67-56-1
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.
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