Registration Dossier
Registration Dossier
Data platform availability banner - registered substances factsheets
Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.
The new ECHA CHEM database has been released by ECHA, and it now contains all REACH registration data. There are more details on the transition of ECHA's published data to ECHA CHEM here.
Diss Factsheets
Use of this information is subject to copyright laws and may require the permission of the owner of the information, as described in the ECHA Legal Notice.
EC number: 222-613-4 | CAS number: 3555-47-3
- 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
![](https://www.echa.europa.eu/o/diss-blank-theme/images/factsheets/A-REACH/factsheet/print_environmental-fate-and-pathways.png)
Biodegradation in water: screening tests
Administrative data
Link to relevant study record(s)
Description of key information
Biodegradation in water: screening tests: 0% biodegradation in 28 days (OECD 301 F) (based on read-across from M3T)
Key value for chemical safety assessment
- Biodegradation in water:
- under test conditions no biodegradation observed
Additional information
Discussion (screening testing)
There are no reliable ready biodegradation data available for M4Q, therefore good quality data for the structurally-related substances, M3T (CAS 17928-28-8) and ViM4Q (CAS 60111-54-8), have been read across.The choice of read-across substance is based on structural similarities between the surrogate and target substance and similarities in their physicochemical properties. M4Q, M3T and ViM4Q are structurally-similar substances.
M4Q and the source substance M3T are branched chain linear siloxanes with five silicon atoms and four silicon atoms respectively, alternated by oxygen atoms. M3T is a tertiary branched methylated siloxane structure of four Si atoms; the longest siloxane chain consists of three silicon atoms and two oxygen atoms, with a Si-O branch on the central silicon atom in the chain. The silicon atoms are fully substituted by methyl groups. M4Q is a quaternary branched methylated siloxane structure of five Si atoms; the longest siloxane chain consists of three silicon atoms and two oxygen atoms, with two Si-O branches on the central silicon atom in the chain. The silicon atoms are fully substituted by methyl groups. M4Q and M3T possess similar physicochemical properties.
The registered substance, M4Q, and the source substance ViM4Q are branched structures of five Si atoms, with four terminal Si atoms linked to a central Si atom by Si-O-Si bonds. In the registered substance, the four terminal Si atoms are fully methyl-substituted, whereas in ViM4Q each of the four terminal Si atoms is substituted by one vinyl and two methyl groups. Evidence within the siloxanes group and from the low functionality organosilicon group suggests that the vinyl group does not confer additional toxicity to substances.
A comparison of the key physicochemical properties is presented in the table below. Both substances have negligible biodegradability and similar moderate hydrolysis rates.
Table: Key physicochemical properties of M4Q and surrogate substances M3T and ViM4Q
Property |
M4Q (3555-47-3) |
M3T (17928-28-8) |
ViM4Q (60111-54-8) |
Molecular weight |
384.85 |
310.69 |
432.89 |
Log Kow |
9.0 |
8.2 |
9.0 |
Log Koc |
6.0 |
5.3 |
6.0 |
Water solubility (mg/l) |
0.1507 µg/l at 23°C |
1.9E-03 mg/l |
<10 ng/L |
Vapour pressure |
15 Pa at 25°C |
210 Pa at 25°C |
<10 Pa at 25°C |
Hydrolysis half- life at pH 7 (h) |
>200-2000 |
630 |
>200 – 2000 |
M4Q, M3T and ViM4Q are within the Reconsile Siloxane Category of substances within which, in general, there is no evidence of any significant biodegradation. Therefore, in the context of the RAAF, Scenario 6 is considered to apply. The Category hypothesis is that read-across of “not readily biodegradable” between siloxanes is appropriate where data are not available for the substance itself. Additional information is given in a supporting report (PFA, 2017at) attached in Section 13.
The table below presents ready biodegradation data for substances within the Siloxane Category.
It is therefore considered valid to read-across the results for M3T and ViM4Q to fill the data gap for the registered substance.
Table : Ready biodegradation data for substances within the Siloxane Category
CAS |
Name |
Readily biodegradable? Yes/no |
Result: Biodegradation after 28 days (%) * |
Guideline |
Test type |
Reliability |
107-46-0 |
Hexamethyldisiloxane |
No |
2% |
OECD 301C |
BOD |
1 |
107-51-7 |
Octamethyltrisiloxane |
No |
-3.70% |
OECD 310 |
CO2 |
1 |
540-97-6 |
Dodecamethylcyclohexasiloxane |
No |
4.5% |
OECD 310 |
CO2 |
1 |
541-02-6 |
Decamethylcyclopentasiloxane |
No |
0.14% |
OECD 310 |
CO2 |
1 |
541-05-9 |
Hexamethylcyclotrisiloxane |
No |
0.06% |
OECD 310 |
CO2 |
1 |
556-67-2 |
Octamethylcyclotetrasiloxane |
No |
3.70% |
OECD 310 |
CO2 |
1 |
1873-88-7 |
1,1,1,3,5,5,5-heptamethyltrisiloxane |
No |
0% |
OECD 310/ ISO Guideline No 14593 |
CO2 |
1 |
2627-95-4 |
1,1,3,3-tetramethyl-1,3-divinyldisiloxane |
No |
0% |
OECD 301D |
BOD |
1 |
17928-28-8 |
1,1,1,3,5,5,5-heptamethyl- 3-[(trimethylsilyl) oxy] trisiloxane |
No |
0% |
OECD 301F |
BOD |
1 |
17955-88-3 |
1,1,1,3,5,5,5-heptamethyl-3-octyltrisiloxane |
No |
10 – 32 % after 25 d |
OECD 301B |
CO2 |
1 |
60111-47-9 |
3-[(dimethylvinylsilyl) oxy]-1,1,5,5-tetramethyl-3-phenyl-1,5-divinyltrisiloxane |
No |
2.20% |
OECD 301F |
BOD |
1 |
69304-37-6 |
1,3-dichloro-1,1,3,3-tetraisopropyldisiloxane |
No |
0% (BOD); 100% (GC) |
OECD 301C |
BOD |
1 |
70940-00-0 |
1,1,7,7, -Tetramethyl-3,3,5,5, -Tetraphenyl-Tetrasiloxane |
No |
9.7 and 9.9% |
OECD 301B |
CO2 |
1 |
180073-46-5 |
Pentasiloxane, 1,1,9,9-tetramethyl-3,3,5,5,7,7-hexaphenyl- |
No |
5.2 and 4.4% |
OECD 301B |
CO2 |
1 |
352230-22-9 |
Siloxanes and Silicones, di-Ph, Ph (trimethylsilyl) oxy |
No |
0% |
OECD 301F |
BOD |
1 |
In the study with M3T, 0% biodegradation was observed in 28 days. The study was conducted according to OECD 301F and is considered to be reliable.
A biodegradation rate of 1.5% in 28 days (CO2 evolution) was determined for ViM4Q in a reliable study conducted according to an appropriate test protocol, and in compliance with GLP.
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.
![ECHA](/o/diss-blank-theme/images/factsheets/A-REACH/factsheet/echa_logo.png)