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EC number: 217-982-3 | CAS number: 2031-62-1
- 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
Hydrolysis
Administrative data
Link to relevant study record(s)
- Endpoint:
- hydrolysis
- Type of information:
- experimental study
- Adequacy of study:
- key study
- Study period:
- 26 Feb 2015
- Reliability:
- 2 (reliable with restrictions)
- Rationale for reliability incl. deficiencies:
- guideline study without detailed documentation
- Qualifier:
- according to guideline
- Guideline:
- EU Method C.7 (Degradation: Abiotic Degradation: Hydrolysis as a Function of pH)
- GLP compliance:
- not specified
- Remarks:
- Inhouse study conducted in order to determine the stability of the substance
- Analytical monitoring:
- yes
- Details on sampling:
- - Sampling intervals for the parent/transformation products: Every 10 to 40 sec a 1H NMR spectrum was acquired after the tubes were transferred into the spectrometer.
- Sample storage conditions before analysis: 1H-NMR measurements were started immediately after mixing the sample and transferring the sample tube into the spectrometer (approx. 2 min) - Buffers:
- - pH: 4
- Composition of buffer: CertiPur, Citric acid + hydrochloric acid + sodium hydroxide
- pH: 7
- Composition of buffer: Baker Analyzed, Potassium dihydrogen phosphate + disodiumhydrogen phosphate
- pH: 9
- Composition of buffer: CertiPur, Boronic acid + potassium chloride + sodium hydroxide - Details on test conditions:
- TEST MEDIUM
- Preparation of test medium: deuterated water / 3-trimethylsilylpropionic acid, sodium salt, 2,2,3,3-tetradeuterated (Na-TSP-d4) (5006.46 mg D2O + 21.53 mg Na-TSP-d4)
- Kind and purity of water: deuterated water - Duration:
- 1 h
- pH:
- 4
- Temp.:
- 25 °C
- Duration:
- 1 h
- pH:
- 7
- Temp.:
- 25 °C
- Duration:
- 1 h
- pH:
- 9
- Temp.:
- 25 °C
- Transformation products:
- yes
- No.:
- #1
- Details on hydrolysis and appearance of transformation product(s):
- At all pH values only signals of ethanol could be observed after the first measurement. There were no signals of ethoxysilane detectable. Therefore it was concluded that hydrolysis was already completed when the first spectrum was measured.
- pH:
- 4
- Temp.:
- 25 °C
- DT50:
- < 2 min
- Type:
- not specified
- pH:
- 7
- Temp.:
- 25 °C
- DT50:
- < 2 min
- Type:
- not specified
- pH:
- 9
- Temp.:
- 25 °C
- DT50:
- < 2 min
- Type:
- not specified
- Validity criteria fulfilled:
- not specified
- Conclusions:
- Diethoxy(methyl)silane CAS 2031-62-1 hydrolysis in less than 2 min at pH 4-9 and 25 °C as identified by 1H-NMR spectroscopy.
Reference
At all pH values only signals of ethanol could be observed after the first measurement. No signals of ethoxysilane could be detected. Thus it was concluded that hydrolysis was already completed when the first spectrum was measured (about 2 min after mixing the test sample) and no exact half-life time or reaction rate could be calculated.
Independently from the hydrolysis reaction a fast decomposition of the Si-H bond was observed. At pH = 4, SiH-containing compounds were well detectable in the first spectra (by a SiMe signal split into a doublet; the SiH-signal itself is hidden by the water peak) and vanished within about 30 min. At pH = 7 and pH = 9, no SiH-containing compounds were detectable from the beginning. This known decomposition reaction comprises the splitting of the Si-H bond by water into siloxanes and molecular hydrogen. At pH = 7 and pH = 9, this hydrogen was observed as gas bubbles in the solution. Accordingly, the corresponding spectra feature broad signals and a low signal-to-noise ratio.
Description of key information
Diethoxy(methyl)silane: hydrolysis half-life < 2 min at 25°C and pH 7
Key value for chemical safety assessment
- Half-life for hydrolysis:
- 2 min
- at the temperature of:
- 25 °C
Additional information
One study is available testing the hydrolysis rate of
diethoxy(methyl)silane (CAS 2031-62-1) (2015). The study was conducted
according to EU Method C.7 and the hydrolysis rate was identified via
1H-NMR Spectroscopy. The hydrolysis was evaluated at pH 4, 7 and 9 and
it was found that the substance hydrolysis in all cases in less than 2
min. The substance is known to stepwisely hydrolyse to the silanol
hydrolysis products methylsilanediol followed by methylsilanetriol
depending on pH. At pH 7 and 9, neither signals of ethoxysilane nor
SiH-containing compounds were detectable from the beginning of the
measurements showing that the final silanol hydrolysis product
methylsilanetriol emerged immediately. At pH 4 no ethoxysilane signals
could be detected at the beginning of the measurement while
SiH-containing compounds were detectable in the first spectra and
vanished within about 30 min indicating that formation of
methylsilanetriol is slower.
The results show that, hydrolysis contributes significantly to the
primary degradation of the substance in the environment.
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