Ethanol, 2,2'-oxybis-, reaction products with 3-(triethoxysilyl)-1-propanamine

Endpoint summary

Description of key information

REACH_data waiving | 28d rep dose tox study

Key value for chemical safety assessment

Repeated dose toxicity: via oral route - systemic effects

Link to relevant study records

Reference

Endpoint:

short-term repeated dose toxicity: oral

Data waiving:

study technically not feasible

Justification for data waiving:

other:

Endpoint conclusion

Endpoint conclusion:

no study available

Justification for classification or non-classification

Ethanol, 2,2'-oxybis-, reaction products with 3-(triethoxysilyl)-1-propanamine (CAS 152261-43-3) is a complex reaction mixture (UVCB) of 3-aminopropyltriethoxysilane (CAS 919-30-2) and diethylene glycol (2,2'-oxydiethanol, CAS‎ 111-46-6). Diethylene glycol is the main component besides smaller amounts of ethanol (CAS 64-17-5). No free 3-aminopropyltriethoxysilane is detectable, because it is covalently bound to the oligomeric structures of the reaction product.

Ethanol, 2,2'-oxybis-, reaction products with 3-(triethoxysilyl)-1-propanamine is unstable upon contact with moisture. lt undergoes further condensation reactions that form highly polymerized poly silicic acids while liberating the diethylene glycol, that was initially bound to the oligomeric structures. The underlying chemistry is commonly known as sol-gel reaction. The poly silicic acid moieties are not stable and prone to further condensation generating waterinsoluble, resinous polymers. The molecular weight of the resulting polymers is predicted to be over 1000. These polymers are stable and not bioavailable.

Due to the reactivity of Ethanol, 2,2'-oxybis-, reaction products with 3-(triethoxysilyl)-1-propanamine the substance cannot be submitted to short-term repeated dose toxicity (28 days study).

Because 3-aminopropyltriethoxysilane is completely consumed into polymer matrix the toxicological profile of Ethanol, 2,2'-oxybis-, reaction products with 3-(triethoxysilyl)-1-propanamine will be mainly determined by diethylene glycol and to a lesser extent by ethanol.

For diethylene glycol a NOAEL of 936 mg/kg was derived after oral exposure of rats over 28 days. In addition, diethylene glycol was assessed within the Community rolling action plan (CoRAP). It was concluded that diethylene glycol does not require classification for specific target organ toxicity after repeated exposure (Substance evaluation conclusion and report for 2,2’-oxydiethanol, 2016). Ethanol is very well investigated and is not classified regards specific target organ toxicity after repeated exposure. For ethanol a LOAEL of 3.16 g/kg was derived after oral exposure of rats over 90 days, which is above the widely used maximum dose of 1 g/kg (see REACH registration dossier, ECHA dissemination site).