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EC number: 249-385-9 | CAS number: 29043-70-7
- 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
Biodegradation in water: screening tests
Administrative data
Link to relevant study record(s)
Description of key information
Biodegradation in water (screening tests): 65% in 28 days (OECD 301B) read-across from a structurally related substance.
Key value for chemical safety assessment
- Biodegradation in water:
- readily biodegradable but failing 10-day window
Additional information
There are no reliable ready biodegradation data available for dimethylbis(octadecyloxy)silane (CAS 29043-70-7), therefore good quality data for the structurally-related substance, trimethyl(octadecyloxy)silane (CAS 18748-98-6), have been read across.
The target and source substance have similar physico-chemical properties and hydrolysis rates; both are very poorly soluble, low volatility and highly absorbing. Hydrolysis rates of >15 h are predicted for both substances. The target substance, dimethylbis(octadecyloxy)silane (CAS 29043-70-7), has two octadecyloxy groups and two methyl groups bonded to a central silicon atom. The source substance, trimethyl(octadecyloxy)silane has a central silicon atom substituted by one octadecyloxy group and three methyl groups. Both substances are predicted to hydrolyse at a similar rate (>15 hours), though hydrolysis rates in the environment are expected to be slower and limited by the high absorption potential and low solubility of the substances. Dimethylbis(octadecyloxy)silane and trimethyl(octadecyloxy)silane have structurally similar silanol hydrolysis products, dimethylsilanediol and trimethylsilanol respectively, whilst the non-silanol hydrolysis product is octadecanol for both substances. Octadecanol is considered to be inherently biodegradable (OECD 1993). Any biodegradation observed for the parent can be attributed principally to the C18 hydrocarbon chain. Since the source substance contains one octadecyloxy group, whilst the target substance contains two octadecyloxy groups, the read-across can be considered conservative.
It is therefore considered valid to read-across the results for trimethyl(octadecyloxy)silane (CAS 18748-98-6) to fill the data gap for the registered substance.
In the study with trimethyl(octadecyloxy)silane (CAS 18748-98-6) 65% biodegradation was observed in 28 days. The study was conducted according to OECD Guideline 301B and is considered reliable. This is selected as the key study.
OECD (1993): Screening Information Data Set (SIDS) of 1-octadecanol (CAS No 112-92-5). OECD High Production Volume Chemicals Programme (1993).
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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