Registration Dossier
Registration Dossier
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EC number: 445-890-5 | CAS number: 201290-01-9
Ecotoxicological Summary
Administrative data
Hazard for aquatic organisms
Hazard for air
Hazard for terrestrial organisms
Hazard for predators
Additional information
Conclusion on classification
The submission substance, N,N-bis(trimethylsilyl)aminopropylmethyldiethoxysilane has two types of hydrolysable group; one silazane (Si-N-Si) and two ethoxy (-OCH2CH3) groups. In contact with water, the silazane (Si-N-Si) bond undergoes instantaneous hydrolysis to form an intermediate hydrolysis product, 3-(diethoxy(methyl)silyl)propylamine and trimethylsilanol. The hydrolysis half-lives of the intermediate hydrolysis product, 3-(diethoxy(methyl)silyl)propylamine has been determined using a validated QSAR estimation method. Hydrolysis half-lives of 0.4 hours at pH 4, 0.4 hours at pH 5, 10 hours at pH 7 and 0.2 hours at pH 9 and 20-25°C were obtained for the intermediate hydrolysis product. The products of ultimate hydrolysis products of 3-(diethoxymethylsilyl)propylamine are 3-(dihydroxymethylsilyl)propylamine and ethanol.
3-(Dihydroxymethylsilyl)propylamine:
In reliable tests conducted with a pre-hydrolysed solution of the registration substance, reliable short-term E(L)C50 values of >40 mg/l in fish (geometric mean for 3-(dihydroxymethylsilyl)propylamine, limit test), >87 mg/l in invertebrates (geometric mean for 3-(dihydroxymethylsilyl)propylamine, limit test) and 41 mg/l in algae (geometric mean for 3-(dihydroxymethylsilyl)propylamine) were determined. It has reliable ErC10 22 mg/l in algae (geometric mean for 3-(dihydroxymethylsilyl)propylamine). These results are based on measured concentrations of the hydrolysis products 3-(dihydroxymethylsilyl)propylamine and trimethylsilanol in the pre-hydrolysed solution of the registration substance.
The registration substance is not readily biodegradable.
These data are consistent with the following classification under Regulation (EC) No 1272/2008 (as amended) (CLP) for 3-(dihydroxymethylsilyl)propylamine in the presence of the other hydrolysis products:
Acute toxicity: Not classified.
Chronic toxicity: Category 3.
Trimethylsilanol:
In reliable tests conducted with a pre-hydrolysed solution of the registration substance, reliable short-term E(L)C50 values of >54 mg/l in fish (geometric mean for trimethylsilanol, limit test), >115 mg/l in invertebrates (geometric mean for trimethylsilanol) and 58 mg/l in algae (geometric mean for trimethylsilanol). It has reliable ErC10 30 mg/l in algae (geometric mean for trimethylsilanol).
The registration substance is not readily biodegradable.
These data are consistent with the following classification under Regulation (EC) No 1272/2008 (as amended) (CLP) for trimethylsilanol in the presence of the other hydrolysis products:
Acute toxicity: Not classified.
Chronic toxicity: Category 3.
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