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EC number: 433-360-6 | CAS number: 34036-80-1
- 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
Link to relevant study record(s)
Description of key information
Key value for chemical safety assessment
- Bioaccumulation potential:
- low bioaccumulation potential
Additional information
Results available from other studies:
The test substance is miscible in all proportions with standard fat at 37°C and has a high (predicted) partition cofficient (log Pow = 11.05), indicating that the substance is potentially bioavailable, and if it is absorbed it has the potential to bioaccumulate. The substance is reactive on exposure to water, hydrolysing rapidly to methyl ethyl ketoxime. It is, therefore, possible that methyl ethyl ketoxime (butanone oxime), rather than the test substance, would be available for adsorption. The oral toxicity studies provided evidence of oral absorption and systemic distribution in the form of clinical signs, changes in blood parameters and macroscopic findings. In the acute dermal study, there was no evidence of adsorption by the dermal route. In the 28-day oral study there were no signs of metabolism or renal excretion. In addition, as the anaemia observed was shown to be reversible in the recovery animals, the test substance or hydrolysis products have been shown not to bioaccumulate. In the mutagenicity studies, there was no observed difference in the presence or absence of S-9 mix and no major differences in the mitotic indices, providing no evidence of metabolism.
Conclusion:
Oral toxicity studies provided evidence of oral absorption and systemic distribution. There was no evidence of metabolism or excretion. There was also no evidence of dermal absorption. There was no evidence of toxicity or clastogenic activity in the mutagenicity studies, either in the presence or absence of metabolic activation.
Hydrolysis and condesation:
Monomeric silicon chemicals are known as silanes. A silane that contains at least one silicon carbon bond, (e.g -Si-CH3) is an organosilane. They normally contain two different types of reactive groups: the hydrolysable groups such as methoxy, ethoxy or acetoxy groups and the organo-functional group, such as epoxy, amino, methacryloxy, or sulfido. It is well known that the Si-OR bonds hydrolyse readily with water, even if only with moisture absorbed on the surface, to form silanol Si-OH groups. These silanol groups can then condense with each other to form polymeric structures with very stable siloxane Si-O-Si bonds.
Previously, to confirm that hydrolysis of silanes is fast, a hydrolysis test have been conducted with the test substance 2-butanone-O-O’-O’’-(phenylsilylidyne)trioxime and the half-life at pH 4, 7 and 9 at 20 ºC was determined to be less that 5 min.
In the hydrolysis test performed on propyltriacetoxysilane, the process was also very fast. The half-life at different pH of test item was determined to be < 37.5 seconds since it completely hydrolysed at 150 seconds after the initial contact with water.
Moreover, the hydrolysis test performed on two acetone oxime silanes, more than 50% of the components hydrolysed in less than 0.75h after starting the dissolution of the test substance at 25 ºC and independently of the pH.
As it is stated in different publications, silanols hydrolyse well in water and the carbon- bounded substituents can have profound effects on the rate of hydrolysis. (Arkles B., Chemtech 1977; Pluddemann E. P., Plenum Press NY, 1982; Kay, B. D. and Assink R. A, J. Non-Cryst. Solids, 1988).
The rates of hydrolysis of the alkoxy groups are generally related to their steric bulk: CH3O>C2H5O> t-C4H9O and a methoxysilane hydrolyzes at 6-10 times rate of an ethoxysilane. Smith (Smith K. J. Org. Chem 1986) proved that increased organic substitution enhances the hydrolysis rate Me3SiOMe> Me2Si(OMe)2> MeSi(OMe)3.
During the hydrolysis test performed with propyltriacetoxysilane, the condensation and polimerysation of the molecules formed in hydrolysis were observed too. It was observed as the phase separation. Unfortunately, this phase separation caused the technical difficulties of the determination of the molecular weight of larger condensation products. It was possible to determined MW of smaller condensates which still are in solutions. Their average MW were between 604-695.
This phase separation as a result of condensation was described by Arkles. The hydrolysis of propyltrimetoxysilane showed that oligomers are formed and branched structures presages phase separation (Arkles B. et al, Silanes and Coupling Agents, 1992).
Taking in account both, the hydrolysis and condensation, it is expected that the observed in the hydrolysis test phase changed product contains large chain polymers with MW>1000.
Authors showed that molecules of MW>1000 cannot be biologically available (Van Gestel et a, Reg. Toxicol. and Pharmacol., 1985, 5, 422-31 and Zitko V, Handbook of Environmental Chemistry, v. 2 221-29).
As stated before, oximino silanes are not stable when exposed to water or moisture and undergo rapid hydrolysis. The hydrolysis of 2-butanone-O-O’-O’’-(phenylsilylidyne)trioxime produces 3 moles of butanone oxime and the silanetriol which condensate to higher molecular weight siloxanes. The polymerization products are considered biologically unavailable and the toxicity is driven by butanone oxime. The toxicity of 2-butanone-O-O’-O’’-(phenylsilylidyne)trioxime could be evaluated as the toxicity of butanone oxime.
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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