Registration Dossier
Registration Dossier
Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.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.
Use of this information is subject to copyright laws and may require the permission of the owner of the information, as described in the ECHA Legal Notice.
EC number: 241-867-7 | CAS number: 17928-28-8
Phototransformation in air
Administrative data
Link to relevant study record(s)
Description of key information
Photodegradation in air: Half-life in air: 10.7 d. Degradation rate constant with OH radicals: 1.5 x 10-12 cm³ molecule-1 s-1
Key value for chemical safety assessment
- Half-life in air:
- 10.7 d
- Degradation rate constant with OH radicals:
- 0 cm³ molecule-1 s-1
Additional information
The SRC AOPWIN program (v1.92) has been used to obtain values of the rate constantkOHfor reaction of M3T with hydroxyl radicals. This prediction method has not been validated to assess applicability to siloxanes; 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)
Where:
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 105OH molecules/ cm3
DT50= half-life
The concentration of hydroxyl radicals in air of 5 x 105OH molecules/ cm3, and the 24 hour photoperiod, are the values specified in the Technical Guidance Document (EC, 2003a).
The results are given in Table 4.1.2.
Table4.1.2Results of photodegradation in air calculations
Parameter |
Result, M3T |
kOH (cm3/ molecule.sec) |
1.5 x 10-12 |
kdegair (d-1) |
0.06 |
DT50(days) |
10.7 |
Information on Registered Substances comes from registration dossiers which have been assigned a registration number. The assignment of a registration number does however not guarantee that the information in the dossier is correct or that the dossier is compliant with Regulation (EC) No 1907/2006 (the REACH Regulation). This information has not been reviewed or verified by the Agency or any other authority. The content is subject to change without prior notice.
Reproduction or further distribution of this information may be subject to copyright protection. Use of the information without obtaining the permission from the owner(s) of the respective information might violate the rights of the owner.
