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: 252-161-3
CAS number: 34708-08-2
Phototransformation in air:
Rate constant for reaction with OH radicals:
Triethoxy(3-thiocyanatopropyl)silane: 3.0E-11 cm3/molecule.sec
(half-life 0.5 days)
(3-Thiocyanatopropyl)silanetriol: 2.2E-11 cm3/molecule.sec
(half-life 0.7 days)
No measured data are available for triethoxy(3-thiocyanatopropyl)silane,
CAS 34708-08-2; EC No. 252-161-3.
Triethoxy(3-thiocyanatopropyl)silane and its hydrolysis products,
(3-thiocyanatopropyl)silanetriol and ethanol (CAS 64-17-5; EC No.
200-578-6) 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 AOPWIN program (v1.92, EPA 2010) has been used to obtain values of
the rate constants kOH for the reactions of
(3-thiocyanatopropyl)silanetriol with hydroxyl radicals. This prediction
method has not been validated to assess applicability to organosilicon
substances; 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
OH Concair = concentration of hydroxyl radicals in
air = 5E+05 OH molecules/ cm3
DT50 = half-life
The concentration of hydroxyl radicals in air of 5E+05 OH molecules/cm3
and the 24 hour photoperiod, are the values specified in ECHA Guidance
on Information requirements and chemical safety assessment, Part R.16
Environmental exposure estimation (ECHA 2016).
The results are given in the table below:
Table: Results of photodegradation in air calculations
The performance of the predictive method (AOPWIN, v1.92) is validated up
to a reaction rate of 1E-10 cm3/mol.sec (equivalent to a
half-life 0.16 day under European conditions of typical atmospheric
hydroxyl radical concentration, as defined in ECHA Guidance R16 (ECHA
2016). The reaction rate is therefore acceptable for use in
environmental exposure assessment.
Measured data for other organosilane substances
Measured data for reaction with hydroxyl radicals in air are available
for some organosilanes. A summary of these measured data is in the table
AOPWIN predictions are also presented for comparison with the measured
Table: Measured data and AOPWIN predictions for reaction with hydroxyl
radicals in air.
Rate constant for reaction with hydroxyl radicals (kOH (cm3/ molecule. sec))
1.28E-12 (Sommerlade et al., 1993)
1.0E-12 (Atkinson, 1991)
8.5E-13 (Tuazon, 2000)
1.19E-12 (Sommerlade et al., 1993)
1.4E-12 (Atkinson, 1991)
1.26E-12 (Sommerlade et al., 1993)
0.5E-12 (Atkinson, 1991)
1.6E-12 (Atkinson, 1991)
8.1E-13 (Tuazon, 2000)
3.95E-12 (Sommerlade et al., 1993)
7.2E-13 (Tuazon, 2000)
The measured values from Sommerlade et al. (1993) and Atkinson
(1991) are in sufficient agreement, and correlate well with the
predicted values. Indeed, the data from these two studies were used in
the training set for the AOPWIN program.
The measured values from Tuazon (2000) indicate slightly lower rates of
reaction for the silanols compared to the AOPWIN predictions and the
measured value from Sommerlade et al. (1993).
EPA, 2010. US Environmental Protection Agency.AOPWIN program v1.92a
ECHA (2016). REACH Guidance on Information Requirements and Chemical
Safety Assessment Chapter R16: Environmental Exposure Assessment
Version: 3.0. February 2016. R.16-3.2.2 Photochemical reactions in the
Sommerlade, R., Parlar, H., Wrobel, D. and Kochs, P.(1993). Product
Analysis and Kinetics of the Gas-Phase Reactions of Selected
Organosilicon Compounds with OH Radicals Using a Smog Chamber-Mass
Spectrometer System. Environ. Sci. Technol. 1993, 27 (12), 2435-2440.
Tuazon E C, Aschmann S M and Atkinson R (2000) Atmospheric Degradation
of Volatile Methyl-Silicon Compounds Environmental Science and
Technology, Vol. 34, No. 10, 1970-1975
Atkinson R. 1991. Kinetics of the Gas-Phase Reactions of a Series of
Organosilicon Compounds with OH and NO3 Radicals and O3 at 297 +/- 2 K.
Environ. Sci. Technol. 25(5):863-866.
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.
Welcome to the ECHA website. This site is not fully supported in Internet Explorer 7 (and earlier versions). Please upgrade your Internet Explorer to a newer version.
Do not show this message again