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EC number: 221-660-8 | CAS number: 3179-76-8
- 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
Ecotoxicological Summary
Administrative data
Hazard for aquatic organisms
Freshwater
- Hazard assessment conclusion:
- PNEC aqua (freshwater)
- PNEC value:
- 0.33 mg/L
- Assessment factor:
- 1 000
- Extrapolation method:
- assessment factor
- PNEC freshwater (intermittent releases):
- 3.3 mg/L
Marine water
- Hazard assessment conclusion:
- PNEC aqua (marine water)
- PNEC value:
- 0.033 mg/L
- Assessment factor:
- 10 000
- Extrapolation method:
- assessment factor
STP
- Hazard assessment conclusion:
- PNEC STP
- PNEC value:
- 86.9 mg/L
- Assessment factor:
- 10
- Extrapolation method:
- assessment factor
Sediment (freshwater)
- Hazard assessment conclusion:
- PNEC sediment (freshwater)
- PNEC value:
- 1.3 mg/kg sediment dw
- Extrapolation method:
- equilibrium partitioning method
Sediment (marine water)
- Hazard assessment conclusion:
- PNEC sediment (marine water)
- PNEC value:
- 0.13 mg/kg sediment dw
- Extrapolation method:
- equilibrium partitioning method
Hazard for air
Hazard for terrestrial organisms
Soil
- Hazard assessment conclusion:
- PNEC soil
- PNEC value:
- 0.07 mg/kg soil dw
- Extrapolation method:
- equilibrium partitioning method
Hazard for predators
Secondary poisoning
- Hazard assessment conclusion:
- no potential for bioaccumulation
Additional information
The hydrolysis half-life of 3-(diethoxmethylsilyl)propylamine is6 h at pH 7, 20-25⁰C. The registered substance will hydrolyse in contact with water and atmospheric moisture to3-(dihydroxymethylsilyl)propylamineand ethanol. REACH guidance (ECHA 2010A, R.16) states that “for substances where hydrolytic DT50 is less than 12 hours, environmental effects are likely to be attributed to the hydrolysis product rather than to the parent itself”. TGD and ECHA guidance, (EC 2003, ECHA 2010A) also suggest that when the hydrolysis half-life is less than 12 hours, the breakdown products, rather than the parent substance, should be evaluated for aquatic toxicity. Therefore, the environmental hazard assessment, including sediment and soil compartments due to water and moisture being present, is based on the properties of the silanol hydrolysis product, in accordance with REACH guidance. As described in Section 1.3, the silanol hydrolysis products may be susceptible to condensation reactions.
READ-ACROSS JUSTIFICATION
In order to reduce animal testing read-across is proposed to fulfil up to REACH Annex IX requirements for the registered substance from substances that have similar structure and physicochemical properties. Ecotoxicological studies are conducted in aquatic medium or in moist environments; therefore the hydrolysis rate of the substance is particularly important since after hydrolysis occurs the resulting product has different physicochemical properties and structure.
In moist medium, 3-(diethoxymethylsilyl)propylamine hydrolyses very rapidly (half-life 6 h at 20-25°C and pH 7) to 3-(dihydroxymethylsilyl)propylamine. 3-(Dihydroxymethylsilyl)propylamine is a silanediol with an amine side chain and a log Kow of -0.9. The non-silanol hydrolysis product ethanol, is not expected to contribute to any adverse effects at the relevant dose levels. This is discussed further below.
In the following paragraphs the read-across approach for 3-(diethoxymethylsilyl)propylamine is assessed for the surrogate substance taking into account structure, hydrolysis rate and physico-chemical properties.
· Read-across from 3-aminopropyltriethoxysilane to 3-(diethoxymethylsilyl)propylamine
3-(Diethoxymethylsilyl)propylamine (CAS 3179-76-8) and 3-aminopropyltriethoxysilane (CAS 919-30-2) both hydrolyse rapidly in contact with water (6 h at pH 7, 20-25⁰C, and 8.5 h at pH 7, 25⁰C respectively). The organosilicon hydrolysis products are 3-(dihydroxymethylsilyl)propylamine and 3-aminopropylsilanetriol respectively. 3-(dihydroxymethylsilyl)propylamine and 3-aminopropylsilanetriol are structural analogues, both containing a propylamine group. The additional methyl group in 3-(dihydroxymethylsilyl)propylamine means only that it has a slightly higher log Kow than the analogous silanetriol but both values are still very low (see below).
The organosilicon hydrolysis products also share similar physicochemical properties: high water solubility, low log Kow (-0.9 and -2.9 respectively) and low MW (135.2 and 137.2 respectively).
· considerations of the non-silanol hydrolysis products.
The other hydrolysis by-product is ethanol for both substances. Ethanol has been studied extensively in the public literature and it is not expected to be hazardous at the concentrations produced during standard environmental studies. The short-term EC50and LC50values for ethanol are in excess of 1000 mg/l (OECD 2004b - SIDS for ethanol, CAS 64-17-5).
Table 7.1 Summary of physico-chemical and ecotoxicological properties for registered and surrogate substances.
CAS Number |
3179-76-8 |
919-30-2 |
Chemical Name |
3-(diethoxymethylsilyl)propylamine |
3-aminopropyltriethoxysilane |
Si hydrolysis product |
3-(dihydroxymethylsilyl)propylamine |
3-aminopropylsilanetriol |
Molecular weight (parent) |
191.35 |
221.37 |
Molecular weight (hydrolysis product) |
135.24 |
137.21 |
log Kow(parent) |
2.5 |
1.7 |
log Kow(silanol hydrolysis product) |
-0.9 |
-2.89 |
Water sol (parent) |
5900 mg/l |
5400 mg/l |
Water sol (silanol hydrolysis product)) |
1E+06 mg/l |
1E+06 mg/l |
Vapour pressure (parent) |
6.9 Pa |
2 Pa |
Vapour pressure (hydrolysis product) |
2.2E-02 Pa |
2.4E-04 Pa |
Hydrolysis t1/2at pH 7 and 25°C |
357 min |
8.5 hours |
Hydrolysis t1/2at pH 4 and 25°C |
<3 min |
0.8 hours (pH5) |
Hydrolysis t1/2at pH 9 and 25°C |
17 min |
0.15 hours |
Short-term toxicity to fish (LC50) |
n/a |
>934 mg/l |
Short-term toxicity to aquatic invertebrates (EC50) |
n/a |
331 mg/l |
Algal inhibition (ErC50and NOEC) |
n/a |
>1000 and 863 mg/l |
Long-term toxicity to fish (NOEC) |
n/a |
n/a |
Long-term toxicity to aquatic invertebrates (NOEC) |
n/a |
n/a |
Long-term sediment toxicity (NOEC) |
n/a |
n/a |
Short-term terrestrial toxicity (L(E)C50) |
n/a |
n/a |
Long-term terrestrial toxicity (NOEC) |
n/a |
n/a |
Conclusion on classification
The registered substance hydrolyses very rapidly in contact with moisture. The silanol hydrolysis product is not readily biodegradable and has a log Kow<<3.
The registered substanceis notclassifiedfor the environment in the EU according to Regulation (EC) No. 1272/2008 because short-term data available for an appropriate surrogate substance indicates the EC50 and LC50 to be >100 mg/l.
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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