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EC number: 915-673-4 | CAS number: 211519-85-6
- Life Cycle description
- Uses advised against
- Endpoint summary
- Appearance / physical state / colour
- Melting point / freezing point
- Boiling point
- Density
- Particle size distribution (Granulometry)
- Vapour pressure
- Partition coefficient
- Water solubility
- Solubility in organic solvents / fat solubility
- Surface tension
- Flash point
- Auto flammability
- Flammability
- Explosiveness
- Oxidising properties
- Oxidation reduction potential
- Stability in organic solvents and identity of relevant degradation products
- Storage stability and reactivity towards container material
- Stability: thermal, sunlight, metals
- pH
- Dissociation constant
- Viscosity
- Additional physico-chemical information
- Additional physico-chemical properties of nanomaterials
- Nanomaterial agglomeration / aggregation
- Nanomaterial crystalline phase
- Nanomaterial crystallite and grain size
- Nanomaterial aspect ratio / shape
- Nanomaterial specific surface area
- Nanomaterial Zeta potential
- Nanomaterial surface chemistry
- Nanomaterial dustiness
- Nanomaterial porosity
- Nanomaterial pour density
- Nanomaterial photocatalytic activity
- Nanomaterial radical formation potential
- Nanomaterial catalytic activity
- Endpoint summary
- Stability
- Biodegradation
- Bioaccumulation
- Transport and distribution
- Environmental data
- Additional information on environmental fate and behaviour
- Ecotoxicological Summary
- Aquatic toxicity
- Endpoint summary
- Short-term toxicity to fish
- Long-term toxicity to fish
- Short-term toxicity to aquatic invertebrates
- Long-term toxicity to aquatic invertebrates
- Toxicity to aquatic algae and cyanobacteria
- Toxicity to aquatic plants other than algae
- Toxicity to microorganisms
- Endocrine disrupter testing in aquatic vertebrates – in vivo
- Toxicity to other aquatic organisms
- Sediment toxicity
- Terrestrial toxicity
- Biological effects monitoring
- Biotransformation and kinetics
- Additional ecotoxological information
- Toxicological Summary
- Toxicokinetics, metabolism and distribution
- Acute Toxicity
- Irritation / corrosion
- Sensitisation
- Repeated dose toxicity
- Genetic toxicity
- Carcinogenicity
- Toxicity to reproduction
- Specific investigations
- Exposure related observations in humans
- Toxic effects on livestock and pets
- Additional toxicological data
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Hydrolysis
Administrative data
Link to relevant study record(s)
- Endpoint:
- hydrolysis
- Data waiving:
- study technically not feasible
- Justification for data waiving:
- the study does not need to be conducted because the substance is highly insoluble in water
- Endpoint:
- hydrolysis
- Type of information:
- (Q)SAR
- Adequacy of study:
- supporting study
- Reliability:
- 2 (reliable with restrictions)
- Rationale for reliability incl. deficiencies:
- results derived from a valid (Q)SAR model, but not (completely) falling into its applicability domain, with adequate and reliable documentation / justification
- Justification for type of information:
- See attached QMRFs/QPRFs
- Principles of method if other than guideline:
- The result was obtained using an appropriate QSAR method (see attached QMRF and QPRF for details).
The model for hydrolysis at pH 7 has been developed for, and applies specifically to di- and tri-alkoxysilanes. It is a multiple linear regression-based model with descriptors representing (i) steric effects of the alkoxy group, (ii) steric effects of the side-chain(s), and (iii) electronic effects of the side-chain(s).
The models for hydrolysis at pH 4, 5 and 9 have been developed for, and apply specifically to organosilicon compounds. They are linear regression-based models where the descriptor is the half-life at pH 7. - Transformation products:
- yes
- No.:
- #1
- No.:
- #2
- pH:
- 4
- DT50:
- >= 0.8 - <= 1.2 h
- Remarks on result:
- other: Temperatures; 20-25°C
- pH:
- 7
- DT50:
- >= 40 - <= 80 h
- Remarks on result:
- other: Temperatures; 20-25°C
- pH:
- 9
- DT50:
- >= 0.5 - <= 1 h
- Remarks on result:
- other: Temperatures; 20-25°C
- Conclusions:
- Hydrolysis half-life values of 0.8-1.2 h at pH 4, 40-80 h at pH 7 and 0.5-1.0 h at pH 9 and 20-25°C were obtained for the S2 constituent of the substance using an accepted calculation method. The result is considered to be reliable.
- Endpoint:
- hydrolysis
- Type of information:
- (Q)SAR
- Adequacy of study:
- supporting study
- Reliability:
- 2 (reliable with restrictions)
- Rationale for reliability incl. deficiencies:
- results derived from a valid (Q)SAR model, but not (completely) falling into its applicability domain, with adequate and reliable documentation / justification
- Justification for type of information:
- See attached QMRFs/QPRFs
- Principles of method if other than guideline:
- The result was obtained using an appropriate QSAR method (see attached QMRF and QPRF for details).
The model for hydrolysis at pH 7 has been developed for, and applies specifically to di- and tri-alkoxysilanes. It is a multiple linear regression-based model with descriptors representing (i) steric effects of the alkoxy group, (ii) steric effects of the side-chain(s), and (iii) electronic effects of the side-chain(s).
The models for hydrolysis at pH 4, 5 and 9 have been developed for, and apply specifically to organosilicon compounds. They are linear regression-based models where the descriptor is the half-life at pH 7. - No.:
- #1
- No.:
- #2
- pH:
- 4
- DT50:
- >= 0.8 - <= 1.6 h
- Remarks on result:
- other: Temperatures; 20-25°C
- pH:
- 7
- DT50:
- >= 40 - <= 140 h
- Remarks on result:
- other: Temperatures; 20-25°C
- pH:
- 9
- DT50:
- >= 0.5 - <= 1.5
- Remarks on result:
- other: Temperatures; 20-25°C
- Conclusions:
- Hydrolysis half-life values of 0.8-1.6 h at pH 4, 40-140 h at pH 7 and 0.5-1.5 h at pH 9 and 20-25°C were obtained for the S5 identified named impurity of the substance using an accepted calculation method. The result is considered to be reliable.
- Endpoint:
- hydrolysis
- Type of information:
- (Q)SAR
- Adequacy of study:
- supporting study
- Reliability:
- 2 (reliable with restrictions)
- Rationale for reliability incl. deficiencies:
- results derived from a valid (Q)SAR model, but not (completely) falling into its applicability domain, with adequate and reliable documentation / justification
- Justification for type of information:
- See attached QMRFs/QPRFs
- Principles of method if other than guideline:
- The result was obtained using an appropriate QSAR method (see attached QMRF and QPRF for details).
The model for hydrolysis at pH 7 has been developed for, and applies specifically to di- and tri-alkoxysilanes. It is a multiple linear regression-based model with descriptors representing (i) steric effects of the alkoxy group, (ii) steric effects of the side-chain(s), and (iii) electronic effects of the side-chain(s).
The models for hydrolysis at pH 4, 5 and 9 have been developed for, and apply specifically to organosilicon compounds. They are linear regression-based models where the descriptor is the half-life at pH 7. - Transformation products:
- yes
- No.:
- #1
- No.:
- #2
- pH:
- 4
- DT50:
- >= 0.8 - <= 1.3 h
- Remarks on result:
- other: Temperatures; 20-25°C
- pH:
- 7
- DT50:
- >= 40 - <= 100 h
- Remarks on result:
- other: Temperatures; 20-25°C
- pH:
- 9
- DT50:
- >= 0.5 - <= 1.1 h
- Remarks on result:
- other: Temperatures; 20-25°C
- Conclusions:
- Hydrolysis half-life values of 0.8-1.3 h at pH 4, 40-100 h at pH 7 and 0.5-1.1 h at pH 9 and 20-25°C were obtained for the S3 constituent of the substance using an accepted calculation method. The result is considered to be reliable.
- Endpoint:
- hydrolysis
- Type of information:
- (Q)SAR
- Adequacy of study:
- supporting study
- Reliability:
- 2 (reliable with restrictions)
- Rationale for reliability incl. deficiencies:
- results derived from a valid (Q)SAR model, but not (completely) falling into its applicability domain, with adequate and reliable documentation / justification
- Justification for type of information:
- See attached QMRFs/QPRFs
- Principles of method if other than guideline:
- The result was obtained using an appropriate QSAR method (see attached QMRF and QPRF for details).
The model for hydrolysis at pH 7 has been developed for, and applies specifically to di- and tri-alkoxysilanes. It is a multiple linear regression-based model with descriptors representing (i) steric effects of the alkoxy group, (ii) steric effects of the side-chain(s), and (iii) electronic effects of the side-chain(s).
The models for hydrolysis at pH 4, 5 and 9 have been developed for, and apply specifically to organosilicon compounds. They are linear regression-based models where the descriptor is the half-life at pH 7. - Transformation products:
- yes
- No.:
- #1
- No.:
- #2
- pH:
- 4
- DT50:
- >= 0.8 - <= 1.4 h
- Remarks on result:
- other: Temperatures; 20-25°C
- pH:
- 7
- DT50:
- >= 40 - <= 120 h
- Remarks on result:
- other: Temperatures; 20-25°C
- pH:
- 9
- DT50:
- >= 0.5 - <= 1.2 h
- Remarks on result:
- other: Temperatures; 20-25°C
- Conclusions:
- Hydrolysis half-life values of 0.8-1.4 h at pH 4, 40-120 h at pH 7 and 0.5-1.2 h at pH 9 and 20-25°C were obtained for the S4 constituent of the substance using an accepted calculation method. The result is considered to be reliable.
Referenceopen allclose all
Description of key information
Hydrolysis half-lives at 20-25°C (QSAR):
S2 = 0.8 - 1.2 h at pH 4, 40 - 80 h at pH 7, 0.5 - 1 h at pH 9
S3 = 0.8 - 1.3 h at pH 4, 40 - 100 h at pH 7, 0.5 - 1.1 h at pH 9
S4 = 0.8 - 1.4 h at pH 4, 40 - 120 h at pH 7, 0.5 - 1.2 h at pH 9
S5 = 0.8 - 1.6 h at pH 4, 40 - 140 h at pH 7, 0.5 - 1.5 h at pH 9
Key value for chemical safety assessment
- Half-life for hydrolysis:
- 140 h
- at the temperature of:
- 20 °C
Additional information
- For S2 constituent, (3-{[3-(trihydroxysilyl)propyl]disulfanyl}propyl)silanetriol
- For S3 constituent, (3-{[3-(trihydroxysilyl)propyl]trisulfanyl}propyl)silanetriol
- For S4 constituent, [3-({[3-(trihydroxysilyl)propyl]disulfanyl}disulfanyl)propyl]silanetriol
- For S5 named impurity, (3-{[3-(trihydroxysilyl)propyl]pentasulfanyl}propyl)silanetriol
The requirement to conduct a hydrolysis study for the substance is waived in accordance with Column 2 of REACH Annex VIII because the substance is insoluble in water. The constituents of the substance have water solubility values of < 1 mg/l.
The hydrolysis rates of the constituents; S2, S3 and S4, and S5 (identified as a named impurity), have been predicted using QSAR estimation methods. The half-lives are shown in Table 4.1.2 below.
As the hydrolysis reaction may be acid or base catalysed, the rate of reaction is expected to be slowest at around pH 7 and increase as the pH is raised or lowered. For an acid-base catalysed reaction in buffered solution, the measured rate constant is a linear combination of terms describing contributions from the uncatalyzed reaction as well as catalysis by hydronium, hydroxide, and general acids or bases.
kobs = k0+ kH3O+[H3O+] + kOH_[OH-] + ka[acid] + kb[base]
At extremes of pH and under standard hydrolysis test conditions, it is reasonable to suggest that the rate of hydrolysis is dominated by either the hydronium or hydroxide catalysed mechanism.
Therefore, at low pH:
kobs≈kH3O+[H3O+]
At pH 4 [H3O+] = 10-4 mol dm-3 and at pH 2 [H3O+] =10-2 mol dm-3; therefore, kobs at pH 2 should be approximately 100 times greater than kobs at pH 4.
The half-life of a substance at pH 2 is calculated based on:
t1/2(pH 2) = t1/2(pH 4) / 100
The calculated half-lives of the constituents at pH 2 and 25°C are S2 = 0.012 h, S3 = 0.013 h, S4 = 0.014 h and S5 = 0.016 h.
Reaction rate increases with temperature therefore hydrolysis will be faster at physiologically relevant temperatures compared to standard laboratory conditions. Under ideal conditions, hydrolysis rate can be recalculated according to the equation:
DT50(XºC) = DT50(T) * e(0.08.(T-X))
Where T = temperature for which data are available and X = target temperature.
The half-lives at 37.5ºC and pH 7 (relevant for lungs and blood) and pH 2 (relevant for conditions in the stomach following oral exposure) are calculated as shown in the table below. At 37.5°C and pH 5.5 (relevant for dermal exposure), the hydrolysis half-life is expected to be between the values for pH 4 and pH 7.
Table 4.1.2: Hydrolysis half-lives for constituents of the submission substance
Constituent name |
Abbreviation |
Half-lives at 20-25°C (h) |
Half-lives at 20-25°C (h) |
Half-lives at 37.5°C |
||||
|
|
pH 4 |
pH 5 |
pH 7 |
pH 9 |
pH 2 |
pH 2 |
pH 7 |
4,4,13,13-Tetraethoxy-3,14-dioxa-8,9-dithia-4,13-disilahexadecane |
S2 |
0.8 - 1.2 |
0.8 - 1.0 |
40-80 |
0.5 - 1.0 |
0.012 |
ca. 16 s |
ca. 28 h |
4,4,14,14-Tetraethoxy-3,15-dioxa-8,9,10-trithia-4,14-disilaheptadecane |
S3 |
0.8 - 1.3 |
0.8 - 1.1 |
40-100 |
0.5 - 1.1 |
0.013 |
ca. 17 s |
ca. 34 h |
4,4,15,15-Tetraethoxy-3,16-dioxa-8,9,10,11-tetrathia-4,15-disilaoctadecane |
S4 |
0.8 - 1.4 |
0.8 -1.2 |
40-120 |
0.5 - 1.2 |
0.014 |
ca. 19 s |
ca. 42 h |
4,4,16,16-Tetraethoxy-3,17-dioxa-8,9,10,11,12-pentathia-4,16-disilanonadecane |
S5 |
0.8 - 1.6 |
0.8 - 1.2 |
40 - 140 |
0.5 - 1.5 |
0.016 |
ca. 21 s |
ca. 51 h |
The products of hydrolysis are bis[3-(trihydroxysilyl)propyl]polysulfides and ethanol.
Bis[3-(trihydroxysilyl)propyl]polysulfides is the hydrolysis product of the multiconstituent substance, consisting of the silanol hydrolysis products:
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.
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