Registration Dossier

Environmental fate & pathways

Endpoint summary

Administrative data

Description of key information

Additional information

Abiotic degradation

[3-(2,3-Epoxypropoxy)propyl]trimethoxysilane is expected to hydrolyse rapidly (half-life 6.5 hours at pH 7 and 24.5°C). A half-life of 0.7 days for reaction with hydroxyl radicals in air has been calculated for [3-(2,3-epoxypropoxy)propyl]trimethoxysilane. However, reaction with water vapour, rather than photolysis, may be the primary degradation process in air.

The initial hydrolysis products are expected to be [3-(2,3-epoxypropoxy)propyl]silanetriol and methanol. Further hydrolysis of the epoxy group is likely to occur, at a slower rate.

Biotic degradation

A reliable ready biodegradation test is available for [3-(2,3-epoxypropoxy)propyl]trimethoxysilane, which indicates that it is not readily biodegradable, and no significant biodegradation in water of the hydrolysis product, [3-(2,3-epoxypropoxy)propyl]silanetriol, is expected.

The chemical safety assessment indicates that it is not necessary to obtain further information on biodegradation via simulation tests in water, sediment or soil.

Table 4.1.5 Degradation rates

Degradation rate in water:

Hydrolysis half-life 6.5 hours at pH 7 and 24.5°C. No significant biodegradation of the hydrolysis product [3-(2,3-epoxypropoxy)propyl]silanetriol.

Degradation rate in sediment:

[3-(2,3-epoxypropoxy)propyl]silanetriol is not expected to biodegrade in sediment.

Degradation rate in soil:

[3-(2,3-epoxypropoxy)propyl]silanetriol is not expected to biodegrade in soil.

Degradation rate in air:

A half-life of 0.7 days for reaction with hydroxyl radicals in air has been calculated for [3-(2,3-epoxypropoxy)propyl]trimethoxysilane; however, reaction with water vapour, rather than photolysis, may be the primary degradation process in air.
[3-(2,3-epoxypropoxy)propyl]silanetriol may undergo indirect phototransformation; calculated half-life for reaction with hydroxyl radicals in air is 0.5 days.