Registration Dossier
Registration Dossier
Data platform availability banner - registered substances factsheets
Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.
The new ECHA CHEM database has been released by ECHA, and it now contains all REACH registration data. There are more details on the transition of ECHA's published data to ECHA CHEM here.
Diss Factsheets
Use of this information is subject to copyright laws and may require the permission of the owner of the information, as described in the ECHA Legal Notice.
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
Testing for toxicity to terrestrial organisms is not considered necessary because:
- The substance hydrolyses rapidly and its hydrolysis products have very low log Kow values (< 3.0). Therefore, partitioning to the terrestrial compartment is expected to be minimal.
- The substance is used under highly controlled conditions and, therefore, exposure of soil is low.
- PNECsoil has been calculated from PNECaquatic (freshwater) by means of the equilibrium partitioning method. The obtained risk characterisation ratio (RCR) based on PNECsoil is << 1.
- An earthworm reproduction test according to OECD Guideline 222 is ongoing (ECHA decision number: TPE-D-2119517436-40-00/F) for the silanol hydrolysis product methylsilanetriol (CAS No. 2445-53-6). This dossier will be updated once the final study report is available.
Additional information
Testing for toxicity to terrestrial organisms is not considered necessary because:
- The substance hydrolyses rapidly and its hydrolysis products have very low log Kow values (< 3.0). Therefore, partitioning to the terrestrial compartment is expected to be minimal.
- The substance is used under highly controlled conditions and, therefore, exposure of soil is low.
- PNECsoil has been calculated from PNECaquatic (freshwater) by means of the equilibrium partitioning method. The obtained risk characterisation ratio (RCR) based on PNECsoil is << 1.
- An earthworm reproduction test according to OECD Guideline 222 is ongoing (ECHA decision number: TPE-D-2119517436-40-00/F) for the silanol hydrolysis product methylsilanetriol (CAS No. 2445-53-6). This dossier will be updated once the final study report is available.
The registered substance dimethoxy(methyl)silane (CAS No. 16881-77-9) hydrolyses rapidly (DT50 = 0.3 h) to the silanol hydrolysis products methylsilanediol and methylsilanetriol and the alcohol hydrolysis product methanol.
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 and is thus considered the relevant assessment entity for the present Chemical Safety Assessment according to REACH.
Therefore, the Chemical Safety Assessment is based on the hydrolysis products methylsilanetriol and methanol rather than the parent substance.
Methanol is known for its absence of environmental toxicity at the concentrations relevant to this dossier (OECD SIDS, 2004), and is therefore not considered contributory to the overall aquatic toxicity of the substance and thus not relevant for the assessment of aquatic toxicity.
Testing considerations for toxicity to terrestrial organisms:
PNECsoil has been calculated from the aquatic data using the Equilibrium Partitioning Method. The risk characterisation ratios (RCR) based on the PNECsoil are << 1. The quantitative Chemical Safety Assessment (conducted according to Annex I of REACH) indicates that the Risk Characterisation Ratio (RCR) is well below 1, even with due consideration of contributing uncertainties, and therefore the risk is adequately controlled.
The hydrolysis product, methylsilanetriol, is not readily biodegradable but has low potential for bioaccumulation, low potential for adsorption and has low bioavailability (based on log Kow < 3.0). Therefore, partitioning to the terrestrial compartment is expected to be minimal. No toxicity was observed in aquatic tests conducted at high concentrations, and there is no reason to expect any specific mechanism of toxicity beyond narcosis. Therefore, the occurrence of more severe toxic effects in the terrestrial compartment that may not have been expressed in the aquatic toxicity studies is considered unlikely.
Methylsilanetriol meets the criteria of the Soil Hazard Category 3 (ECHA 2017, guidance part R7(c) Table R.7.11—2) due to its potential persistence. In accordance with the screening assessment for Soil Hazard Category 3 substances, a PNECsoil was calculated from the aquatic data by means of the equilibrium partitioning method for the purpose of the chemical safety assessment. The obtained risk characterisation ratios are below 1. In addition, a confirmatory long-term soil toxicity test should be conducted.
No effects on aquatic microorganisms in a study according to OECD Guideline 209 were observed, therefore testing with soil microorganisms is not considered necessary.
Overall it is concluded that the risk characterisation conclusion is sufficiently conservative with respect to any uncertainties and therefore further in vivo testing is not considered necessary. However, in order to comply with ECHA testing requirements for Soil Hazard Category 3 substances, a chronic earthworm reproduction test with methylsilanetriol is ongoing (ECHA decision number: TPE-D-2119517436-40-00/F).
Details on how the PNEC and the risk characterisation ratio have been derived can be found in IUCLID Section 6.0 and Chapters 9 and 10 of the Chemical Safety Report, respectively.
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.