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Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.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: 219-137-4 | CAS number: 2370-88-9
- 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
Endpoint summary
Administrative data
Description of key information
Additional information
HD4 is a liquid at standard temperature and pressure, with a melting point of <-20°C, and a boiling point of 134 to 135°C. It has a density of 0.98 g/cm3at 20°C and a viscosity of 6.9 mm²/s (static) at 20°C. The measured vapour pressure is 479 Pa at 20°C.
The substance is classified as flammable on the basis of a flash point of 27.9°C. It has a self-ignition temperature of 270°C, is not explosive and is not oxidising.
In contact with water it reacts very rapidly (half-life 2.2 min at pH 7 and 22.5°C); this initial half-life relates to opening of the siloxane ring. The end product of the hydrolysis is methylsilanetriol; hydrogen gas is produced as a by-product of the reaction. At high concentrations, condensation products of methylsilanetriol and of intermediate hydrolysis products can form, but this is not relevant for environmental concentrations. The intermediate products of hydrolysis are linear siloxanols and methylsilanediol.
Methylsilanetriol is predicted to be miscible with water, with low log Kow(-2.4, predicted). It is not surface active and does not undergo significant dissociation within the environmentally relevant range. It is less volatile than the parent substance (vapour pressure = 0.05 Pa, predicted).
Predicted values for the key physicochemical properties of the expected intermediate and final hydrolysis products are shown in the table below.
Table: Key physicochemical properties of some expected hydrolysis products of HD4
|
SMILES |
VP / Pa at 25°C |
WS / mg/l |
Log Kow |
Hydrolysis at pH 7 and 20-25°C / h |
Intermediate HP1 |
[Si](O[Si](O[Si](O)C)C)(O[Si](O)C)C |
1.7E-04 |
7.5E+02 |
2.5 |
0.2 h |
Intermediate HP2 |
[Si](O[Si](O[Si](O)C)C)(O)C |
3.8E-03 |
1.3E+04 |
1.6 |
0.4 h |
Intermediate HP3 |
C[Si](O)O[Si](O)C |
1.3E-01 |
1.9E+05 |
0.6 |
1.0 h |
Methylsilanediol |
C[Si](O)O |
6.5 Pa |
7.6E+05 |
-1.0 |
n/a |
Methylsilanetriol |
C[Si](O)(O)O |
0.05 Pa |
1.0E+06 |
-2.4 |
n/a |
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.