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EC number: 250-807-9 | CAS number: 31795-24-1
- 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
Biodegradation in water: screening tests
Administrative data
Link to relevant study record(s)
Description of key information
Biodegradation in water, screening tests: 0% in 28 days (read-across from an analogous/structurally related substance).
Key value for chemical safety assessment
- Biodegradation in water:
- under test conditions no biodegradation observed
Additional information
Potassium methylsilanetriolate dissociates completely into potassium and methylsilanetriolate ions in aqueous solution. The substance as sold is only stable at high pH (pH >12). When the pH is reduced, the concentration of the non-ionised form (methylsilanetriol) increases. The first pKa of methylsilanetriol is approximately 10. At pH 9.0 and below, the substance is no longer in the ionised form and methylsilanetriol predominates. Methylsilanetriol undergoes reversible condensation reactions in solution to give siloxane dimers, linear and cyclic oligomers. The overall rate and extent of condensation is dependent on the amount of substance present (the nominal loading), temperature, pH of the system and what else is present in the solution. Under conditions relevant for the environment (close to neutral pH and low concentration), the neutral monomer (methylsilanetriol) predominates (>99%). The dimers and oligomers are expected to be less biodegradable than the monomer. Therefore, read-across from trimethylsilanol, which is a close structural analogue of methylsilanetriol, is considered to be appropriate.
This analogue group for the ready biodegradability endpoint consists of a number of sub-classes of substances (based on structure/functionality) with different main codes (used to represent the different sub-classes). However, read-across is carried out between substances with the same main code in most cases.
The table below presents ready biodegradation data for substances within the sub-class I-2 of Alkoxysilanes, silanols, acetoxysilanes and chlorosilanes etc. Potassium methylsilanetriolate (CAS 31795-24-1) and trimethylsilanol (CAS 1066-40-6) are members of this sub-class.
It is therefore considered valid to read-across the results for trimethylsilanol (CAS 1066-40-6) to fill the data gap for the registered substance. Additional information is given in a supporting report (PFA, 2013f) attached in Section 13 of the IUCLID 5 dossier.
Table: Ready biodegradation data available for substances within the relevant sub-class I-2 of chemicals
CAS |
Name |
Main code |
Readily biodegradable? Yes/no |
Result: Biodegradation after 28 days (%) |
Guideline |
Reliability |
Corrected % biodegradation once alkoxy/acetoxy biodegradation is accounted for[1] |
1066-40-6 |
Hydroxytrimethylsilane |
I-2 |
No |
0% |
OECD 310 and ISO Guideline N 14593 |
1a |
0 |
13154-25-1 |
Chlorotri(3-methyl-propyl)silane |
I-2-M-C |
No |
0% |
OECD 301B |
1a |
0 |
139147-73-2 |
Silane, dichlorodicyclopentyl- |
I-2-D-C |
No |
0.80% |
OECD 301D |
2b |
1 |
98-12-4 |
Cyclohexyltrichlorosilane |
I-2-D-C |
No |
0% |
OECD 301C |
1a |
0 |
124-70-9 |
Dichloro(methyl)(vinyl)silane |
I-2-D-C |
No |
-6.78% |
OECD 301 A |
1a |
0 |
17865-32-6 |
Cyclohexyldimethoxymethylsilane |
I-2-D-Me-H |
No |
15-17% |
OECD 301D |
1a |
-5 |
126990-35-0 |
Dicyclopentyldimethoxysilane |
I-2-D-Me-M |
No |
12% |
OECD 301C |
1 |
-5 |
None46 |
t-butoxycyclopentyldimethoxysilane |
I-2-D-Me-M |
No |
15% BOD; 25% TOC; 100% GC |
OECD 301C |
1a |
7 |
17689-77-9 |
Triacetoxyethylsilane |
I-2-T-A |
Yes |
74% in 21 days |
EC C4-A |
1a |
-1 |
17980-47-1 |
Triethoxyisobutylsilane |
I-2-T-Et-H |
Yes |
75% |
OECD 301D |
1a |
15 |
2943-75-1 |
Triethoxyoctylsilane |
I-2-T-Et-M |
No |
31.50% |
OECD 301D |
1a |
-11 |
35435-21-3 |
Triethoxy(2,4,4-trimethylpentyl)silane |
I-2-T-Et-M |
No |
13% |
OECD310 |
1a |
-30 |
16415-13-7 |
Triethoxyhexadecylsilane |
I-2-T-Et-S |
No |
43% by BOD; 74% by HPLC |
MITI |
1c |
16 |
1067-25-0 |
Trimethoxypropylsilane |
I-2-T-Me-H |
No |
54% |
Annex V C4-A |
1a |
4 |
87135-01-1 |
1,6-Bis(trimethoxysilyl)hexane |
I-2-T-Me-H |
yes but not meeting 10-day window |
74% |
OECD 301B |
1a |
24 |
None45 |
Mixture of 1,1- and 1,2-bis(trimethoxysilyl)ethane |
I-2-T-Me-H |
Yes |
93% BOD; 78% TOC; 100% GC (ethanol?) |
"Biodegradation study of chemical substances bymicroorganisms and the like"[2] |
1a |
18 |
18395-30-7 |
Trimethoxy(2-methylpropyl)silane |
I-2-T-Me-H |
No |
36 - 47% |
OECD 301B |
1a |
4 |
2768-02-7 |
Trimethoxyvinylsilane |
I-2-T-Me-H |
No |
51% |
OECD 301F |
1a |
-9 |
142877-45-0 |
Silane, trimethoxy(1,1,2-trimethylpropyl)- |
I-2-T-Me-S |
No |
31% |
OECD 301D |
1a |
-2 |
[1]The negative values in this column are where the biodegradation rate observed in the test is less than that expected assuming only alkoxy/acetoxy parts biodegrade. This could be due to low solubility of parent substance or low rates of hydrolysis. These values should in effect be considered as zero.
[2]Stipulated in "Testing Method for New Chemical Substances etc." (Kanhogyo No.5, Yakuhatsu 615, 49Kikyoku No.392, July 13, 1974 )
In the study with trimethylsilanol (CAS 1066-40-6), 0% biodegradation was observed in 28 days.
The study was conducted according to OECD 310 and ISO Guideline N 14593 and is considered to be reliable. This is selected as the key study. The study is considered to be reliability 1 (reliable without restrictions); the read across of the result is considered to be reliability 2 (reliable with restrictions).
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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