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EC number: 201-083-8 | CAS number: 78-10-4
- 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
Water solubility
Administrative data
Link to relevant study record(s)
- Endpoint:
- water solubility
- Data waiving:
- study scientifically not necessary / other information available
- Justification for data waiving:
- the study does not need to be conducted because the substance is hydrolytically unstable at pH 4, 7 and 9 (half-life less than 12 hours)
- Endpoint:
- water solubility
- 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 and falling into its applicability domain, with adequate and reliable documentation / justification
- 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 is an adaptation of the existing SRC model WaterNT v 1.01, aka WaterFrag, which is a component of the EPI Suite. This model is based on fragment values. That is, the chemical structure is broken down into its constituent functional groups, and the contribution of each group toward the overall solubility is calculated. Certain correction factors may also apply. Whilst this method is good in principle, it suffers from not having reliable fragment values for substances containing Si-O bonds. Therefore, multiple linear regression on a set of organosilicon compounds has been used to generate new fragment values for silicon and oxygen bound to silicon (with separate values for –OH and other oxygen). The adapted model applies to substances containing Si-O bonds. - Water solubility:
- 8 600 mg/L
- Temp.:
- 20 °C
- pH:
- 7
- Conclusions:
- A water solubility of 8600 mg/l at 20°C was obtained for the substance using an appropriate calculation method. The result is considered reliable.
Referenceopen allclose all
Description of key information
Water solubility [tetraethyl orthosilicate]: Not relevant due to very rapid hydrolysis in contact with water
Water solubility
[monosilicic acid]: Approximately 100-150 mg SiO2/L, with
condensation occurring at higher concentrations.
Water solubility [ethanol]:
miscible at 20°C
Key value for chemical safety assessment
- Water solubility:
- 8 600 mg/L
- at the temperature of:
- 20 °C
Additional information
The requirement to conduct a water solubility study is waived because in contact with water, the submission substance hydrolyses rapidly to form monosilicic acid (CAS 10193-36-9; EC No. 233-477-0) and ethanol (CAS 64-17-5; EC No. 200-578-6).
However, the water solubility of the substance has been predicted as 8600 mg/L at 20°C using a validated QSAR estimation method. Also, a water solubility value of 1.49 g/L (1490 mg/L) at 23°C was determined for the substance based on an estimation of a saturated solution of the test substance in water (Altmann 2002). The relative amounts of water and test substance present were estimated by 1H-NMR spectroscopy. Due to the method used, saturation of the test solution may not have been obtained. Also, an attempt was made to measure the water solubility of the submission substance based on the concentration of the substance in buffer solutions during a hydrolysis study. Water solubility in the range 258-829 µg/g (258-829 mg/L) was obtained (Dow Corning Corporation 2003). The reliability of this study is unassignable. Therefore, the predicted result is considered as a true indication of the water solubility of the submission substance and is used for assessment purposes.
Silicic acid condenses at concentrations above approximately 100-150 mg/L as SiO2 to give insoluble amorphous polysilicic acid. At concentrations >100-150 mg/L as SiO2 according to published sources, monomeric silicic acid condenses rapidly into a highly cross-linked network (gel) or colloidal particles of polysilicic acid. The condensation rate is dependent on temperature, concentration, and acidity or alkalinity of the system. A dynamic equilibrium is established between monomer, oligomers and insoluble amorphous polysilicic acid. Further details about the chemistry of inorganic silicic acid is given in (PFA 2015ao) attached to Section 13.
Ethanol is miscible with water (Riddick J A 1986).
References:
PFA (2015ao). Peter Fisk Associates, The aquatic chemistry of inorganic silicic acid generators, PFA.404.001.001
Riddick, J.A.; Bunger,W.B.; Sakano,T.K.; Organic Solvents: Physical Properties and Methods of Purification. Techniques of Chemistry. 4th ed: Wiley-Interscience. 2: pp.1325 1986
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