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Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.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: 439-510-7 | CAS number: 149048-48-6
- 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
The substance is a multi-constituent substance with two main constituents, N-[3-(trimethoxysilyl)propyl]-1,3-benzenedimethanamine (Constituent 1) and 3-[(2,2-dimethoxy-1,2-azasilolidin-1-yl)benzenedimethanamine (Constituent 2).
Since the substance is a multi-constituent substance, two aspects need to be considered in relation to physicochemical properties:
1) In the context of raw material handling and safe use it is important to understand the properties of the product as a whole
The substance is a liquid at room temperature and pressure, with a freezing temperature of <-80°C. No measured boiling point can be determined because the substance undergoes thermal decomposition from about 275°C. It has a measured relative density of 1.09 at 20°C. The vapour pressure of the whole substance was determined to be 3.6E-03 Pa at 20°C and 6.1E-03 Pa at 25°C.
The substance is not classified for flammability according to Regulation (EC) No. 1272/2008, on the basis of a measured flash point of 153±2°C. It has a measured auto-ignition temperature of 320°C at 1014.3 - 1022 hPa and is not explosive and not oxidising on the basis of chemical structure. Also, none of the constituents of the substance are expected to be surface active.
2) For the purposes of assessing environmental fate and behaviour, individual constituents may behave independently of each other. It is therefore essential to consider the properties of individual constituents, and whole property data may have no real scientific meaning or significance.
The predicted key physicochemical properties of the individual constituents are shown in Table 1.1
Table 1.1: Predicted key physicochemical properties of constituents of the substance
Constituent number |
Constituent name |
SMILES |
Molecular weight (g/mol) |
Vapour pressure at 25°C (Pa) |
log Kow at 20°C |
Water solubility at 20°C (mg/L) |
pKa |
1 |
N-[3-(trimethoxysilyl)propyl]-1,3-benzenedimethanamine |
NCc1cccc(c1)CNCCC[Si](OC)(OC)OC |
298.46 |
1.3E-03 |
1.5 for the unionised form For the ionised form; using pKa2: -1.3 at pH 7, -4 at pH 2, -4 at pH 4, 0.63 at pH 9 and 20°C |
4.1E+04 |
pKa1 = 8.6
pKa2 = 9.8 |
2 |
3-[(2,2-Dimethoxy-1,2-azasilolidin-1-yl)benzenedimethanamine |
NCc1cccc(c1)CN1CCC[Si]1(OC)OC |
266.42 |
9.7E-03 |
Not determined, due to very rapid hydrolysis |
Not determined, due to very rapid hydrolysis |
Not determined, due to very rapid hydrolysis |
Final silanol HP |
N-[3-(trihydroxysilyl)propyl]-1,3-benzenedimethanamine |
NCc1cccc(c1)CNCCC[Si](O)(O)O |
256.38 |
<1.0E-03 |
-1.6 for the unionised form For the ionised form; using pKa2: -4 at pH 7, -4 at pH 2, -4 at pH 4, -3 at pH 9 and 20°C
|
1.0E+06; limited by condensation at about 1000 mg/L |
pKa1 = 8.8
pKa2 = 10.4
pKa3 = 12.1 |
Both constituents contain methoxysilane groups (Si-OMe) which are susceptible to hydrolysis in contact with water. In addition to the Si-OMe group in both constituents, Constituent 2 also contains a silyl amine group (Si-N) which reacts very rapidly in contact with water.
The constituents undergo hydrolysis reactions as shown in Figure 1 (attached in Section 13). Each constituent undergoes three consecutive hydrolysis reactions. The first hydrolysis step for Constituent 1 is loss of a methoxy group to give Intermediate 1 (N-[3-(hydroxy(dimethoxy)silyl)propyl]-1,3-benzenedimethanamine) and methanol according to the following equation:
C11H17N2Si(OCH3)3 + H2O → C11H17N2Si(OCH3)2OH + CH3OH
Predicted hydrolysis half-lives for this reaction are 0.3 h at pH 4, 4.8 h at pH 7, 0.1 h at pH 9 and 20-25C.
The first hydrolysis step for Constituent 2 is ring-opening at the Si-N bond. This also results in Intermediate 1, N-[3-(hydroxy(dimethoxy)silyl)propyl]-1,3-benzenedimethanamine (but not methanol) according to the following equation:
C11H16N2Si(OCH3)2 + H2O → C11H17N2Si(OCH3)2OH
The silyl amine (Si-N) bond is highly susceptible to hydrolysis by both acid-catalysed and base-catalysed mechanisms. Therefore, the Si-N bond present in Constituent 2 will undergo very rapid hydrolysis on contact with water. The half-life is estimated as <1 minute at pH 4, 7 and 9.
Intermediate 1 undergoes two further hydrolysis steps involving loss of its two methoxy groups to give Intermediate 2 (N-[3-(diihydroxy(methoxy)silyl)propyl]-1,3-benzenedimethanamine) and the final hydrolysis product (N-[3-(trihydroxysilyl)propyl]-1,3-benzenedimethanamine) according to the following equations:
C11H17N2Si(OCH3)2OH + H2O → C11H17N2Si(OCH3)(OH)2+ CH3OH
C11H17N2Si(OCH3)(OH)2→ C11H17N2Si(OH)3+ CH3OH
The predicted half-lives for these reactions are each <0.3 h at pH 4, <4.8 h at pH 7 and <0.1 h at pH 9.
Thus, the intermediate and final silicon-containing hydrolysis products are the same for Constituent 1 and Constituent 2. The final silicon-containing hydrolysis product is N-[3-(trihydroxysilyl)propyl]-1,3-benzenedimethanamine (1 mole) for both constituents. The co-product of hydrolysis is methanol for both constituents; 3 moles for Constituent 1 and 2 moles for Constituent 2.
Therefore, the requirements for testing of water-based physicochemical properties for the substance are waived on the basis of instability in water. The properties of the hydrolysis products, N-[3-(trihydroxysilyl)propyl]-1,3-benzenedimethanamine and methanol are assessed instead.
The saturation concentration in water of the silanol hydrolysis products, N-[3-(trihydroxysilyl)propyl]-1,3-benzenedimethanamine, is limited by condensation reactions that can occur over time at loadings above approximately 1000 mg/L. However, it is very hydrophilic (calculated solubility is 1E+06 mg/L at 20°C using a QSAR method). The unionised form of the silanol hydrolysis product has a predicted log Kow of -1.6. In solution, the amine groups will protonate; therefore, the estimated log Kow was corrected for ionisation based on the second the pKa (which will generate the unionised form) using the equation CORR = 1/1 +10A(pH-pKa) [where A = 1 for acids, -1 for bases; pH = pH-value of the environment; pKa = acid/base dissociation constant]. Log Kow values and vapour pressure of the silanol hydrolysis product are reported in Table 1.1. The silanol hydrolysis product is not surface active.
Additional information
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.