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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
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- Nanomaterial pour density
- Nanomaterial photocatalytic activity
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- Nanomaterial catalytic activity
- Endpoint summary
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- 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
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- Biotransformation and kinetics
- Additional ecotoxological information
- Toxicological Summary
- Toxicokinetics, metabolism and distribution
- Acute Toxicity
- Irritation / corrosion
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- Genetic toxicity
- Carcinogenicity
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- Specific investigations
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- Additional toxicological data
Endpoint summary
Administrative data
Description of key information
- 4,4,13,13-tetraethoxy-3,14-dioxa-8,9-dithia-4,13-disilahexadecane (S2, CAS 56706-10-6)
- 4,4,14,14-tetraethoxy-3,15-dioxa-8,9,10-trithia-4,14-disilaheptadecane (S3, CAS 56706-11-7) and
- 4,4,15,15-tetraethoxy-3,16-dioxa-8,9,10,11-tetrathia-4,15-disilaoctadecane (S4, CAS 40372-72-3).
- 4,4,16,16-Tetraethoxy-3,17-dioxa-8,9,10,11,12-pentathia-4,16-disilanonadecane (S5, named impurity)
- In the context of raw material handling and safe use it is important to understand the properties of the product as a whole.
- For the purposes of assessing environmental fate and behaviour, in the environment, individual constituents may behave independently of each other.
- S2 constituent: 0.8-1.2 h at pH 4, 40-80 h at pH 7 and 0.5-1.0 h at pH 9
- S3 constituent: 0.8-1.3 h at pH 4, 40-100 h at pH 7 and 0.5-1.1 h at pH 9
- S4 constituent: 0.8 – 1.4 h at pH 4, 40-120 h at pH 7 and 0.5-1.2 h at pH 9
- S5 named impurity: 0.8 – 1.6 h at pH 4, 40-140 h at pH 7 and 0.5-1.5 h at pH 9
The submission substance is a multi-constituent substance with three constituents and a named impurity:
The substance is a liquid at room temperature and pressure, with a melting point of < -20°C at 1013 hPa and an estimated boiling point ≥ 269°C at 1013 hPa. It has a measured relative density of 1.0813 at 20°C and a measured kinematic viscosity value of 10.74 mm2/s at 20°C. A measured vapour pressure of 9 Pa at 20°C which was determined for the S2 constituent of the substance is used for assessment purposes.
The substance is not classified for flammability according to Regulation (EC) No. 1272/2008, on the basis of a measured flash point of > 110°C at 1013 hPa and predicted boiling point ≥ 269°C at 1013 hPa. It has a measured auto-ignition temperature of 250°C at 998 -1004 hPa and is not explosive and not oxidising based on examination of the structure. Also, none of the constituents or impurities with similar chemical structure of the substance are expected to be surface active.
Since the substance is a multi-constituent substance; two aspects need to be considered in relation to physicochemical properties:
It is therefore essential to consider the properties of individual constituents, and whole property data may have no real scientific meaning or significance. However, it has been concluded for the submission substance, that the chemical safety assessment should be conducted as if the substance is a mono-constituent substance because of the very similar physicochemical properties for the constituents. The details considered in reaching that conclusion are presented below.
The individual constituents of the parent substance have estimated vapour pressures shown in Table 1.3.2, and the S2 constituent has a measured vapour pressure of 9 Pa at 25°C. Each constituent has predicted water solubilities of < 1 mg/l at 20°C, a predicted log Kow of 5.2 at 20°C and predicted vapour pressure ≤ 0.46. Table 1.3.2 gives the predicted result for each constituent of the substance.
Table 1.3.2: Predicted physicochemical properties of constituents of the substance
Constituent No. (Name) | Constituent | SMILES | Molecular Weight (g/mol) | Vapour Pressure* (Pa at 25°C) | Log Kow | Water solubility (mg/l) |
1 (S2) | 4,4,13,13-Tetraethoxy-3,14-dioxa-8,9-dithia-4,13-disilahexadecane | CCO[Si](OCC)(OCC)CCCSSCCC[Si](OCC)(OCC)OCC | 474.82 | ≤ 0.46 | 5.2 | 0.014 |
2 (S3) | 4,4,14,14-Tetraethoxy-3,15-dioxa-8,9,10-trithia-4,14-disilaheptadecane | CCO[Si](OCC)(OCC)CCCSSSCCC[Si](OCC)(OCC)OCC | 506.88 | ≤ 0.46 | 5.2 | 0.012 |
3 (S4) | 4,4,15,15-Tetraethoxy-3,16-dioxa-8,9,10,11-tetrathia-4,15-disilaoctadecane | CCO[Si](OCC)(OCC)CCCSSSSCCC[Si](OCC)(OCC)OCC | 538.94 | ≤ 0.46 | 5.2 | 0.010 |
Named impurity (S5) | 4,4,16,16-Tetraethoxy-3,17-dioxa-8,9,10,11,12-pentathia-4,16-disilanonadecane | CCO[Si](OCC)(OCC)CCCSSSSSCCC[Si](OCC)(OCC)OCC | 571.02 | ≤ 0.46 | 5.2 | 0.0086 |
*The values reported here is the predicted vapour pressure for individual constituents of the substance; however, a measured vapour pressure of 9 Pa at 20°C is used for assessment purposes as a worst-case approach.
In contact with water, the constituents react moderately to slowly, with predicted half-lives at 20-25°C of:
The equations for the reactions are reported below:
S2:
(CH3CH2O)3SiCH2CH2CH2SSCH2CH2CH2Si(OCH2CH3)3 + 6H2O → (OH)3SiCH2CH2CH2SSCH2CH2CH2Si(OH)3 + 6CH3CH2OH
S3:
(CH3CH2O)3SiCH2CH2CH2SSSCH2CH2CH2Si(OCH2CH3)3 + 6H2O → (OH)3SiCH2CH2CH2SSSCH2CH2CH2Si(OH)3 + 6CH3CH2OH
S4:
(CH3CH2O)3SiCH2CH2CH2SSSSCH2CH2CH2Si(OCH2CH3)3 + 6H2O → (OH)3SiCH2CH2CH2SSSSCH2CH2CH2Si(OH)3 + 6CH3CH2OH
S5:
(CH3CH2O)3SiCH2CH2CH2SSSSSCH2CH2CH2Si(OCH2CH3)3 + 6H2O → (OH)3SiCH2CH2CH2SSSSSCH2CH2CH2Si(OH)3 + 6CH3CH2OH
The silanol hydrolysis products are bis[3-(trihydroxysilyl)propyl]polysulfides.
Bis[3-(trihydroxysilyl)propyl]polysulfides is the hydrolysis product of the multiconstituent substance, consisting of the silanol hydrolysis products:
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 silanols are predicted to have very low vapour pressures. The saturation concentration in water of the silanol hydrolysis products is limited by condensation reactions to approximately 100 mg/l. However, they are very hydrophilic (calculated solubility is 1.0E+06 mg/l using a QSAR method) and have a predicted low log Kow (-3.0).
None of the hydrolysis products is expected to be surface active and they are not expected to undergo significant dissociation within the environmentally relevant range. The measured first dissociation constant, pKa, of a structurally analogous silanetriol (phenylsilanetriol) is approximately 10.
The physicochemical properties of the silanol hydrolysis products are reported in Table 1.3.3.
Table 1.3.3: Predicted physicochemical properties of silanol hydrolysis products
Hydrolysis product | SMILES | Molecular Weight (g/mol) | Vapour Pressure* (Pa at 25°C) | Log Kow | Water solubility (mg/l |
(3-{[3-(Trihydroxysilyl)propyl]disulfanyl}propyl)silanetriol | O[Si](O)(O)CCCSSCCC[Si](O)(O)O | 306.50 | 6.3E-12 | -3.0 | 1E+06 |
(3-{[3-(Trihydroxysilyl)propyl]trisulfanyl}propyl)silanetriol | O[Si](O)(O)CCCSSSCCC[Si](O)(O)O | 338.56 | 6.3E-12 | -3.0 | 1E+06 |
[3-({[3-(Trihydroxysilyl)propyl]disulfanyl}disulfanyl)propyl]silanetriol | O[Si](O)(O)CCCSSSSCCC[Si](O)(O)O | 370.62 | 6.3E-12 | -3.0 | 1E+06 |
(3-{[3-(Trihydroxysilyl)propyl]pentasulfanyl}propyl)silanetriol | O[Si](O)(O)CCCSSSSSCCC[Si](O)(O)O | 402.7 | 6.3E-12 | -3.0 | 1E+06 |
Since the three constituents and the named impurity have very similar physicochemical properties and they’re silanol hydrolysis products have very similar physicochemical properties, environmental and human health exposure assessments were conducted as if the substance were a mono-constituent substance.
Additional information
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