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EC number: 245-876-7 | CAS number: 23779-32-0
- 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
- Concentration of the silanol; the greater the initial concentration, the greater the degree of condensation. Significant condensation is not expected at concentrations less than approximately 100 mg/l, but is dependent on specific conditions.
- pH; the condensation reaction may be either acid or base catalysed.
- Temperature.
- Other species present.
- The nature of the R group
- The number of Si-OH groups; silanetriols condense more rapidly than silanediols.
Physico-chemical properties
3-(triethoxysilyl)propyl]urea is a white solid at standard temperature and pressure, with a measured melting point of 51°C and a measured boiling point of 316.9°C. It has a measured density of 1.06g/cm3at 20°C, and a predicted vapour pressure of 3.1E-03 Pa at 25°C.
The substance is classified as non-flammable. It is not pyrophoric or flammable in contact with water, and it is not explosive and not oxidising on the basis of chemical structure. It is not self-heating.
It is not surface active. A first pKa value of 1.0 was determined for the amine groups (parent compound) using an appropriate calculation method.
In contact with water, 3-(triethoxysilyl)propyl]urea reacts rapidly (calculated half-life of approximately 16.4 hours at 20-25°C, pH 7) to produce [3-(trihydroxysilyl)propyl]urea and ethanol according to the following equation:
(CH3CH2O)3SiCH2CH2CH2NHC(=O)NH2 + 3H2O
→ (HO)3SiCH2CH2CH2NHC(=O)NH2 + 3CH3CH2(OH)
Therefore, requirements for testing of the water-based physicochemical properties for the substance and measurement of the surface tension are waived on the basis of instability in water. The properties of the hydrolysis products are assessed in instead.
The silanol hydrolysis product, [3-(trihydroxysilyl)propyl]urea, is predicted to be very soluble in water at 20oC (1.0E+06 mg/l) and has a log Kow of -3.3 at 20°C (predicted). It is less volatile than the parent substance with a vapour pressure of 4.1E-07 at 25°C (predicted). The first dissociation constant (hydroxyl groups) of a structurally analogous silanetriol (phenylsilanediol) has been reported to be around pKa10.
Ethanol is miscible with water, has low log Kow(-0.3) and high vapour pressure (7910 Pa at 20°C).
Silanetriols may undergo condensation reactions to give siloxane dimers, oligomers and polymers, according to the scheme:
RSi(OH)3 ⇄ RSi(OH)2OSi(OH)2R ⇄ RSi(OH)2O[Si(R)(OH)O]nSi(OH)2R
(where R is an alkyl or aryl side-chain)
A highly cross-linked gel may form. The degree of condensation that will occur may vary with:
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