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Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.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

Administrative data

Link to relevant study record(s)

Description of key information

Key value for chemical safety assessment

Additional information

Trimethoxy(2,4,4-trimethylpentyl)silane and its hydrolysis product (2,4,4-trimethylpentyl)silanetriol contain no chromophores that would absorb visible or UV radiation, so direct photolysis is not likely to be significant. Indirect photolysis resulting from gas-phase reaction with photochemically-produced hydroxyl radicals may occur.

The SRC AOPWIN program (v1.92) has been used to obtain values of the rate constant kOH for reaction of Trimethoxy(2,4,4-trimethylpentyl)silane and its hydrolysis product (2,4,4-trimethylpentyl)silanetriol with hydroxyl radicals. This prediction method has not been validated to assess applicability to silanes and silanols; therefore, there is uncertainty associated with the calculated values obtained.

The overall half-life in air under default conditions of hydroxyl radical concentration was calculated using the following expressions:

kdegair(d-1) = kOH(cm3/molecule.sec) x OH Concair(molecules/cm3) x 24 x 3600

DT50(d) = ln 2/ kdegair(d-1)


kdegair= total rate constant for degradation in air

kOH= rate constant for reaction with hydroxyl radicals

OH Concair= concentration of hydroxyl radicals in air = 5 x 105 OH molecules/ cm3

DT50= half-life

The results are given in table below:

Table: Results of photodegradation in air calculations


Result, Trimethoxy(2,4,4-trimethylpentyl)silane


kOH(cm3/ molecule.sec)

8.76 x 10-12

16.63 x 10-12

kdegair (d-1)