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

Endpoint summary

Description of key information

REACH_LD50 > 2000 mg/kg bw | rat (female) | OECD 423 | #key study##Analogy (152261-44 -4)#

Key value for chemical safety assessment

Acute toxicity: via oral route

Link to relevant study records

Reference

Endpoint:

acute toxicity: oral

Type of information:

read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

key study

Study period:

February - March 2018

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Justification for type of information:

Analogy to Ethanol, 2,2'-[1,2-ethanediylbis(oxy)]bis-, RP with 3-(triethoxysilyl)-1-propanamine, CAS 152261-44-4:

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 (CAS ‎111-46-69). 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.

A comparable reaction mixture namely Ethanol, 2,2'-[1,2-ethanediylbis(oxy)]bis-, reaction products with 3-(triethoxysilyl)-1-propanamine (CAS 152261-44-4) was submitted to acute toxicity testing. The tested reaction product does contain triethylene glycol instead of diethylene glycol as main component and ethanol. The data on Ethanol, 2,2'-[1,2-ethanediylbis(oxy)]bis-, reaction products with 3-(triethoxysilyl)-1-propanamine were used for evaluation of the reaction product with diethylene glycol.

Ethanol, 2,2'-oxybis-, reaction products with 3-(triethoxysilyl)-1-propanamine are unstable upon contact with moisture. The product 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 water insoluble, resinous polymers. The molecular weight of the resulting polymers is predicted to be over 1000. These polymers are stable and not bioavailable.

For the above mentioned reasons the toxicological profile of Ethanol, 2,2'-oxybis-, reaction products with 3-(triethoxysilyl)-1-propanamine will be mainly determined by the solvents, which are very well investigated.

In contrast to triethylene glycol, diethylene glycol is officially classified as harmful after ingestion (Annex VI to Regulation (EC) No 1272/2008). Ethanol, 2,2'-oxybis-, reaction products with 3-(triethoxysilyl)-1-propanamine with its content of > 50 % diethylene glycol is therefore also regarded as harmful after ingestion and requires corresponding classification and labelling.

Reason / purpose for cross-reference:

read-across source

Qualifier:

according to guideline

Guideline:

OECD Guideline 423 (Acute Oral toxicity - Acute Toxic Class Method)

Qualifier:

according to guideline

Guideline:

EU Method B.1 tris (Acute Oral Toxicity - Acute Toxic Class Method)

Qualifier:

according to guideline

Guideline:

EPA OPPTS 870.1100 (Acute Oral Toxicity)

Species:

rat

Strain:

other: WISTAR Crl: WI(Han)

Sex:

female

Key result

Sex:

female

Dose descriptor:

LD50

Effect level:

> 2 000 mg/kg bw

Based on:

test mat.

Remarks:

CAS 152261-44-4

Key result

Sex:

female

Dose descriptor:

LD50 cut-off

Effect level:

5 000 mg/kg bw

Based on:

test mat.

Remarks:

CAS 152261-44-4

Interpretation of results:

Category 5 based on GHS criteria

Conclusions:

The median lethal dose of Ethanol, 2,2’-[1,2-ethanediylbis(oxy)] bis-, reaction products with 3-(triethoxysilyl)-1-propanamine after a single or double oral administration to female rats, observed over a period of 14 days is: LD50cut-off (rat): 5000mg/ kg bw.
The most relevant clinical findings in the animals treated with the test item at a dose of 2000 mg/kg bw were reduced spontaneous activity, piloerection, hunched posture, ataxia and half eyelid-closure. All animals recovered within up to 2 days post-dose.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed

Acute toxicity: via inhalation route

Endpoint conclusion

Endpoint conclusion:

no study available

Acute toxicity: via dermal route

Endpoint conclusion

Endpoint conclusion:

no study available

Justification for classification or non-classification

Ethanol, 2,2'-oxybis-, reaction products with 3-(triethoxysilyl)-1-propanamine is a complex reaction mixture (UVCB) of 3-aminopropyltriethoxysilane (CAS 919-30-2) and diethylene glycol (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 water-insoluble, resinous polymers. The molecular weight of the resulting polymers is predicted to be over 1000. These polymers are stable and not bioavailable.

Since 3-aminopropyltriethoxysilane is completely consumed into the polymer matrix, it is therefore considered that 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.

As the major component diethylene glycol is officially classified as harmful after ingestion (Annex VI to Regulation (EC) No 1272/2008), the Ethanol, 2,2'-oxybis-, reaction products with 3-(triethoxysilyl)-1-propanamine with its content of >50% diethylene glycol is also regarded as harmful after ingestion and requires corresponding classification and labelling.