Registration Dossier

Data platform availability banner - registered substances factsheets

Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.

The new ECHA CHEM database has been released by ECHA, and it now contains all REACH registration data. There are more details on the transition of ECHA's published data to ECHA CHEM here.

Diss Factsheets

Environmental fate & pathways

Biodegradation in water: screening tests

Currently viewing:

Administrative data

Link to relevant study record(s)

Description of key information

Biodegradation in water (screening tests): 69% in 28 days (OECD 301F), read-across from a structurally related substance.

Key value for chemical safety assessment

Biodegradation in water:
readily biodegradable but failing 10-day window

Additional information

There are no reliable ready biodegradation data available for 3-[dimethoxy(methyl)silyl]propyl methacrylate (CAS No. 14513-34-9), therefore good quality data for the structurally-related substance, 3-trimethoxysilylpropyl methacrylate (CAS No. 2530-85-0), have been read across.

3-[Dimethoxy(methyl)silyl]propyl methacrylate (CAS No. 14513-34-9) has a predicted hydrolysis half-life of 0.1 h at pH 4, 0.2 h at pH 5, 1.5 h at pH 7 and 0.03 h at pH 9 and 20-25°C, to form 3-[dihydroxy(methyl)silyl]propyl methacrylate and methanol. Similarly, 3-trimethoxysilylpropyl methacrylate (CAS No. 2530-85-0) has measured hydrolysis half-lives of 0.018 h at pH 4, 1.87 h at pH 7 and 0.068 h at pH 9 and 20°C to form 3-trihydroxysilylpropyl methacrylate and methanol. Extensive or complete hydrolysis in the course of the 28-day ready biodegradation study is to be expected. In view of the rapid hydrolysis, it is the silanol hydrolysis product that is relevant for the environmental risk assessment.

Methanol is readily biodegradable (OECD 2004).

3-[Dimethoxy(methyl)silyl]propyl methacrylate (CAS No. 14513-34-9) and 3-trimethoxysilylpropyl methacrylate (CAS No. 2530-85-0) are within an analogue group of substances within which substances are readily biodegradable failing the 10-day window. The conclusion is based on reliable data available for three substances, all of which are methacrylates. Once the biodegradation of the alkoxy groups is taken into account there is evidence that the methacrylate side-chain is biodegrading to some extent.  However, the silanol hydrolysis product would not be considered as readily biodegradable.

The table below presents ready biodegradation data for substances within the analogue group III-2 (Substances (chlorosilanes, silanes, alkoxysilanes or siloxanes) containing acrylate functionality in the hydrocarbon chain attached to Si (i.e. remote from the Si)). 3-[Dimethoxy(methyl)silyl]propyl methacrylate (CAS No. 14513-34-9) and 3-trimethoxysilylpropyl methacrylate (CAS No. 2530-85-0) are members of this analogue group.

It is therefore considered valid to read-across the results for 3-trimethoxysilylpropyl methacrylate (CAS No. 2530-85-0) to fill the data gap for the registered substance. Additional information is given in a supporting report (PFA, 2013h) attached in Section 13.

Table: Ready biodegradation data available for substances within the relevant III-2 analogue group of chemicals

CAS

Name

Readily biodegradable? Yes/no

Result: Biodegradation after 28 day

Guideline

Reliability

Corrected % biodegradation once alkoxy/acetoxy biodegradation is accounted for

5577-72-0

2-Propenoic acid, 2-methyl-, (triethoxysilyl)methyl ester

yes but not meeting 10-day window

73%

OECD 301F

1

18

2530-85-0

3-trimethoxysilylpropyl methacrylate

yes but not meeting 10-day window

69%

OECD 301F

1 - Key

39

3978-58-3

2-Propenoic acid,2-methyl-, (diethoxymethylsilyl)methyl ester

yes but not meeting 10-day window

73%

OECD 301F

1

29

In the study with 3-trimethoxysilylpropyl methacrylate (CAS No. 2530-85-0), 69% biodegradation was observed in 28 days.

The study was conducted according to OECD 301F and is considered reliable (Grutzner 2002). This result is selected as the key study because it was the study conducted most recently.

Another study conducted according to EU Method C.4-A (Determination of the "Ready" Biodegradability - Dissolved Organic Carbon (DOC) Die-Away Test) gave a result of 74% biodegradation in 28 days (not passing the 10-day window) (Enste-Diefenback 1995). This is used as a supporting study.

References:

OECD (2004): SIDS Initial Assessment Report for SIAM 19, Berlin, Germany, 18-20 October 2004, Methanol, CAS 67-56-1.

PFA, 2013h, Peter Fisk Associates, Biodegradation III-2 Analogue Group report, PFA.300.005.005