Registration Dossier
Registration Dossier
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EC number: 203-233-8 | CAS number: 104-75-6
Endpoint summary
Administrative data
Link to relevant study record(s)
Description of key information
Based on the chemical structure, the substance is likely to be absorbed after oral, dermal and inhalation exposure. If not unchanged excreted, excretion of metabolites may occur predominately via urine. The substance and its metabolites are not expected to accumulate. The toxicity behaviour of the substance is primary characterized by local effects rather than systemic effects.
Key value for chemical safety assessment
- Bioaccumulation potential:
- no bioaccumulation potential
Additional information
The Primary Amines-category is represented by the structure with a single and primary amino-group R-NH2, where R is an alkyl group that may be linear, branched or alicyclic; the alkyl group may include an atom or group that will not react with or substantially affect the properties of the amine function. The tendency to share the non-bonded electron pair on the nitrogen underlies the chemical behavior of amines as a group.
Amines are classified as organic bases because of the unshared pair of electrons of the nitrogen atom. Primary amines are polar compounds and can form intermolecular hydrogen bonds. As a result, most primary amines are liquids at standard temperature and pressure and have higher boiling points than alkanes of equivalent molecular weight, but lower boiling points than the corresponding alcohols and carboxylic acids. Since primary amines are capable of forming hydrogen bonds with water, those compounds with fewer than five or six carbon atoms are generally water soluble. 2-Ethylhexylamine is liquid at room temperature.
2-Ethylhexylamine is corrosive to skin and eyes. The vapor pressure is low to moderate with 1.6 hPa at 20°C. Partition coefficient n-octanol/water (log Pow) is 2.82, the water solubility is 2.5 g/L at 20°C.
Absorption
2-Ethylhexylamine has a molecular weight below 500 g/mol and moderate log Pow value between -1 and 4 which favors in general oral absorption by passive diffusion (ECHA (2014)).
Based on molecular weights (< 500 g/mol), water solubility (100-10000 mg/L) and log Pow values (between 1 and 4), absorption through the skin is possible (ECHA (2014)).
Considering the low to moderate vapor pressure (< 0.5 kPa) of the substance and the resulting low volatility, exposure as vapor is very limited. In the case that inhalation occurs, the substance may directly cross the respiratory tract epithelium by passive diffusion based on log Pow values between -1 and 4 (ECHA (2014)).
However, 2 -Ethylhexylamine is highly corrosive and the destruction of epithelial barriers can increase uptake or absorption of the substance.
Metabolism/excretion
Different enzyme-catalyzed reactions of primary amines are described leading to enhanced hydrophilicity (detoxification) and excretion. In general, aliphatic primary amines of the structure R-CH2-NH2 are metabolized to the corresponding acid and urea.
One important oxidative pathway is catalyzed by the monoamine oxidase and cytochrome P450 dependent mixed function oxygenases (MFO). The carbon close to the amino group will be oxidized to give a labile carbinolamine that decompose spontaneously to an aldehyde and ammonia.
In another mechanism, the initial oxidation occurred at the nitrogen center resulting in hydroxylamine which rearranges to form the carbinolamine. This carbinolamine decomposes again to an aldehyde and ammonia.
The aldehyde will be oxidized by various aldehyde dehydrogenases to from the respective carboxylic acid which will be conjugated by Phase II enzymes and then excreted, most likely via urine.
Urea will be incorporated into amino acid or converted to urea, which is then excreted.
Conclusion
Based on the chemical structure, the substance is likely to be absorbed after oral, dermal and inhalation exposure. If not unchanged excreted, excretion of metabolites may occur predominately via urine. The substance and its metabolites are not expected to accumulate.
The toxicity behavior of the substance is primary characterized by local, corrosive effects rather than systemic effects.
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