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EC number: 214-189-4 | CAS number: 1112-39-6
- 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:
- 13 Feb - 05 Mar 2008
- Reliability:
- 1 (reliable without restriction)
- Rationale for reliability incl. deficiencies:
- guideline study
- Qualifier:
- according to guideline
- Guideline:
- OECD Guideline 111 (Hydrolysis as a Function of pH)
- Version / remarks:
- 2004
- Qualifier:
- according to guideline
- Guideline:
- EU Method C.7 (Degradation: Abiotic Degradation: Hydrolysis as a Function of pH)
- Version / remarks:
- 1992
- GLP compliance:
- yes
- Radiolabelling:
- no
- Analytical monitoring:
- yes
- Details on sampling:
- - Sampling method: Before and after incubation, 1 mL of the test sample solution was diluted with 2 mL of acetone and filtered (0.2 μm nylon filter). 1 μL aliquots of the test solutions at each pH value were analysed by measuring the FID signal of Dimethoxydimethylsilane after GC separation of the injected sample solution.
- Buffers:
- Buffer Solution pH 4.0
- pH: 4
- Composition of buffer: Biphthalate buffer, pH 4.00 ± 0.02 (25 °C), J.T. Baker, Art. No. 5657
Buffer Solution pH 7.0
- pH: 7
- Composition of buffer:Phosphate buffer, pH 7.00 ± 0.02 (25 °C), J.T. Baker, Art. No. 5656
Buffer Solution pH 9.0
- pH: 9
- Composition of buffer: Borate/Potassium chloride/NaOH buffer, pH 9.00 ± 0.02 (20 °C), J.T. Baker, Art. No. 7145
Nitrogen was passed through the buffer solutions for 1 min. - Details on test conditions:
- TEST SYSTEM
- Type, material and volume of test flasks, other equipment used: All glassware, which must be inert in the pH range applied, was rinsed with sterile buffer. The hydrolysis was carried out in flasks, which were stoppered or sealed with an inert material (e. g. glass).
- Sterilisation method: The buffer solutions were sterilized for 25 min in an autoclave prior to first use.
- If no traps were used, is the test system closed/open?: Test system is closed.
- Is there any indication of the test material adsorbing to the walls of the test apparatus?: No
TEST MEDIUM
- Volume used/treatment: 50 mL
- Kind and purity of water: Commercial buffer solutions
- Preparation of test medium: The test item was dissolved in 1 mL of acetone, filled up with 50 mL of buffer solution and treated in an aultrasonic bath for 1 min. Afterwards the solutions were filtered (0.2 µm nylon filter). To obtain a test solution of not more than half the water solubility, 25 mL of these solutions were diluted with buffer solution to obtain a volume of 50 mL.
- Identity of co-solvent: acetone - Duration:
- 120 h
- pH:
- 4
- Temp.:
- 50 °C
- Initial conc. measured:
- 0 other: µg/mL
- Duration:
- 3.85 h
- pH:
- 7
- Temp.:
- 25 °C
- Initial conc. measured:
- >= 343.868 - <= 389.596 other: µg/mL
- Duration:
- 1.65 h
- pH:
- 9
- Temp.:
- 25 °C
- Initial conc. measured:
- >= 33.243 - <= 34.439 other: µg/mL
- Number of replicates:
- Duplicate
- Positive controls:
- no
- Negative controls:
- no
- Preliminary study:
- The results of pH 4.0 at 50 °C: no test item could be detected not even directly after preparation of the samples.
The results of pH 7.0 and pH 9.0 showed a significant degradation of Dimethoxydimethylsilane at 50 °C. - Transformation products:
- yes
- Remarks:
- Transformation products were not specifically analysed in the study.
- No.:
- #1
- No.:
- #2
- pH:
- 4
- Temp.:
- 50 °C
- Remarks on result:
- not determinable because of methodological limitations
- pH:
- 7
- Temp.:
- 25 °C
- DT50:
- < 0.6 h
- Type:
- (pseudo-)first order (= half-life)
- pH:
- 9
- Temp.:
- 25 °C
- DT50:
- < 0.6 h
- Type:
- (pseudo-)first order (= half-life)
- Details on results:
- TEST CONDITIONS
- pH, sterility, temperature, and other experimental conditions maintained throughout the study: Yes - Validity criteria fulfilled:
- not applicable
- Remarks:
- No validity criteria specified in the OECD guideline.
- Conclusions:
- Hydrolysis half-lifes of < 0.6 h at pH 7 and 9 and 25 °C were determined in a study conducted according to OECD 111. The study is considered reliable.
Reference
The hydrolysis of the test item was performed at 50.0 °C ± 0.1 °C at each of pH 4.0, pH 7.0 and pH 9.0 in a preliminary test. The solubility of Dimethoxydimethylsilane in buffers was very low. Thus, a solubilizer (acetone) was used. The solubility of Dimethoxydimethylsilane in buffer pH 4.0 was very low in spite of the solubilizer, no test item could be detected not even directly after preparation of the samples. Therefore, no further test according to the guideline could be performed. For pH 7.0 and pH 9.0 a main test at 25 °C was performed in order to calculate the hydrolytic half-life.
Table 1: Results of hydroylsis at pH 4.0 and 50 °C
Sample No. 1 |
Sample No. 2 |
||
Time [h] |
Concentration measured [µg/mL] |
Time [h] |
Concentration measured [µg/mL] |
0.00 |
0.00 |
0.00 |
0.00 |
0.55 |
0.00 |
0.55 |
0.00 |
2.4 |
0.00 |
2.4 |
0.00 |
120 |
0.00 |
120 |
0.00 |
Table 2: Results of hydrolysis at pH 7.0 and 25 °C
|
Sample No. 1 |
Sample No. 2 |
||
Time [h] |
Concentration measured [µg/mL] |
Hydrolysis [%] |
Concentration measured [µg/mL] |
Hydrolysis [%] |
0.00 |
343.868 |
0 |
389.596 |
0 |
0.55 |
150.701 |
56 |
168.159 |
57 |
1.10 |
53.538 |
84 |
61.708 |
84 |
1.65 |
22.048 |
94 |
24.287 |
94 |
2.20 |
9.931 |
97 |
9.521 |
98 |
2.75 |
4.461 |
99 |
4.028 |
99 |
3.30 |
0.000 |
100 |
0.000 |
100 |
3.85 |
0.000 |
100 |
0.000 |
100 |
Table 3: Results of hydrolysis at pH 9.0 and 25 °C
|
Sample No. 1 |
Sample No. 2 |
||
Time [h] |
Concentration measured [µg/mL] |
Hydrolysis [%] |
Concentration measured [µg/mL] |
Hydrolysis [%] |
0.00 |
34.439 |
0 |
33.243 |
0 |
0.55 |
0.000 |
100 |
0.000 |
100 |
1.10 |
0.000 |
100 |
0.000 |
100 |
1.65 |
0.000 |
100 |
0.000 |
100 |
Description of key information
DT50 < 0.6 hours at pH 7 and 25 °C (OECD 111)
Key value for chemical safety assessment
Additional information
One guideline study investigating the hydrolysis of dimethoxydimethylsilane (CAS No. 1112-39-6) is available. The study was performed according to OECD 111 and GLP. First a preliminary study was conducted at pH 4, 7 and 9 at 50 °C for 120 h. Dimethoxydimethylsilane was found to be hydrolytically unstable at pH 7 and pH 9. At pH 4 the substance could not be analytically determined by GC/FID analysis. This could either be caused by immediate hydrolysis after addition to the buffer solution or due to analytical limitations. Based on this result a main test was only performed at pH 7 and pH 9 at 25 °C. The test duration for the main test was 3.85 h for pH 7 and 1.65 h for pH 9. For pH 7 and pH 9, the half-life time was determined to be less than 0.6 h at 25 °C. Therefore, it can be concluded that dimethoxydimethylsilane will hydrolyse rapidly under environmentally relevant conditions. The formation of hydrolysis products was not measured in this study but based on the chemical structure of the substance dimethylsilanediol (1 mole, CAS 1066-42-8) and methanol (2 moles) are the expected hydrolysis products.
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