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nonapotassium 2,4,6-trihydroxy-4-methyl-3,5-dioxa-2,4,6-trisilaheptane-2,6-bis(olate) 2,6,8-trihydroxy-4,6-dimethyl-3,5,7-trioxa-2,4,6,8-tetrasilanonane-2,4,8-tris(olate) 6-hydroxy-2,4,6-trimethyl-1,3,5,2,4,6-trioxatrisilinane-2,4-bis(olate) dihydroxy(methyl)silanolate {[dihydroxy(methyl)silyl]oxy}(hydroxy)methylsilanolate
EC number: 935-877-7 | CAS number: -
- 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
No data on the repeated dose toxicity of reaction mass of potassium methylsiliconate are available, therefore data on trimethoxy(methyl) silane have been read-across. Exposure to trimethoxy(methyl) silane (MTMS) was associated with organ weight and/or histomorphological changes in males (liver, thymus, thyroid, duodenum, jejunum, and red blood cell) and females (liver, thyroid, duodenum, jejunum, and adrenal gland) at dose levels at or above 250 mg/kg bw/day. A marked increase in prothrombin time was observed for males at 250 and 1000 mg/kg bw/day whereas females were unaffected. Exposure was also associated with increased blood platelet concentration for males and females at 1000 mg/kg bw/day. These data support a NOAEL for the toxicity phase of the study of 50 mg/kg bw/day. There were several instances of urinary bladder hyperplasia; the study authors considered these to be the result of a reaction to a foreign body in the form of amorphous material.
There is also a 90-day inhalation study on trimethoxy(methyl) silane. Based on the increased incidence of grossly observed urinary bladder calculi along with the kidney dilation at the 400 ppm exposure level, the NOAEL for trimethoxy(methyl) silane vapor administered six hours per day, five days per week for a 90-day interval via whole-body inhalation exposure to male and female Sprague-Dawley rats, was 100 ppm (equivalent to 557.14 mg/m3).
Key value for chemical safety assessment
Repeated dose toxicity: via oral route - systemic effects
Endpoint conclusion
- Dose descriptor:
- NOAEL
- 50 mg/kg bw/day
Repeated dose toxicity: inhalation - systemic effects
Endpoint conclusion
- Dose descriptor:
- NOAEC
- 557.14 mg/m³
Additional information
No data on the oral repeated dose toxicity of reaction mass of potassium methylsiliconate are available. Reaction mass of potassium methylsiliconate is a multi-constituent substance containing methylsilanetriolate, dimers and oligomers of methylsilanetriolate, and potassium hydroxide. In contact with water the substance is dissolving. The resulting aqueous solution is only stable at high pH. As the pH is lowered, polymerisation occurs. Under comparable conditions of concentration and pH methylsilanetriolate is equivalent to the parent acid, methylsilanetriol.
The surrogate substance, trimethoxy(methyl)silane (CAS 1185-55-3), hydrolyses in contact with water at pH 7 (half-life approx. 2 hours), producing methanol and methylsilanetriol. Under acidic conditions, such as in the stomach following oral ingestion, hydrolysis is very rapid. Since potassium ions will not contribute to any systemic toxicity effect, and methanol does not contribute any significant repeated dose toxicity to rodents at the dose levels tested (*see below), and both substances share the same silanol product it is considered appropriate to read across the available data on trimethoxy(methyl)silane. Dimers and oligomers of methylsilanetriol are expected have lower toxicity than the corresponding monomer, therefore use of data on MTMS represents a worst-case interpretation.
Local irritant or corrosive effects due to the high pH of an aqueous solution of the registered substance are not addressed by the read-across data. It should be noted that at a concentration of 100 ppm (the NOAEC for MTMS), significant local effects would be expected, therefore the local NOAEC of an aqueous solution of so
lid phase potassium methylsilanetriolate is expected to be lower than the systemic NOAEC read-across from MTMS.*Methyltrimethoxysilane (MTMS) hydrolyses to give methylsilanetriol and methanol. For the oral route, a NOAEL of 500 mg/kg was determined for methanol in a study to which reliability could not be assigned. This was based on fairly minor effects at 2500 mg/kg; there was stated to be increased liver weights, with increased liver enzymes. These liver effects were also observed for MTMS, but in females only, and not the same enzymes. Therefore, from the limited information on oral ingestion of methanol, there is no reason to think that the effects for MTMS were caused by methanol. For the inhalation route, the NOEL for methanol was 0.13 mg/l (10 ppm) based on slight body weight and organ weight changes, but even effects at 1000 ppm were not considered to be toxicologically relevant. Effects for MTMS occurred at doses of 400 ppm and above, and were more significant than those of methanol. Therefore, the effects of MTMS cannot be attributed to methanol.
Justification for classification or non-classification
The available data do not suggest that reaction mass of potassium methylsiliconate should be classified for effects following repeated exposure.
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