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EC number: 458-430-3 | CAS number: -
- 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
Hydrolysis
Administrative data
Link to relevant study record(s)
- 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 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 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
- No.:
- #3
- pH:
- 4
- DT50:
- <= 0.3 h
- Remarks on result:
- other: 20-25°C
- Remarks:
- The result is for the cis and trans isomers
- pH:
- 7
- DT50:
- <= 5.5 h
- Remarks on result:
- other: 20-25°C
- Remarks:
- The result is for the cis and trans isomers
- pH:
- 9
- DT50:
- <= 0.1 h
- Remarks on result:
- other: 20-25°C
- Remarks:
- The result is for the cis and trans isomers
- Conclusions:
- Hydrolysis half-life values at 20-25°C of ≤5.5 h at pH 7, ≤0.3 h at pH 4 and ≤0.1 h at pH 9 were obtained for the cis and trans isomers of Constituent 1 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 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 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:
- 0.1 h
- Remarks on result:
- other: 20-25°C
- pH:
- 5
- DT50:
- 0.2 h
- Remarks on result:
- other: 20-25°C
- pH:
- 7
- DT50:
- 1.6 h
- Remarks on result:
- other: 20-25°C
- pH:
- 9
- DT50:
- 0.03 h
- Remarks on result:
- other: 20-25°C
- Conclusions:
- Hydrolysis half-life values at 20-25°C of 0.1 h at pH 4, 1.6 h at pH 7 and 0.03 h at pH 9 were obtained for Constituent 2 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 using QSAR method:
Constituents 1a and 1b [cis and trans isomers] = ≤5.5 h at pH 7, ≤0.3 h at pH 4 and ≤0.1 h at pH 9
Constituent 2 = 1.6 h at pH 7, 0.1 h at pH 4 and 0.03 h at pH 9
Key value for chemical safety assessment
Additional information
The submission substance is a multi-constituent substance. Each constituent contains two or three Si-OR’ groups which can hydrolyse to form Si-OH and ROH. The hydrolysis study is not a requirement at Annex VII but information about hydrolysis rates is important for the interpretation of other studies. Therefore, predictions for the rate of hydrolysis of the constituents are made using a validated QSAR method.
Constituent 1a and Constituent 1b: 1-[(2-ethylhexyl)oxy]propenyloxydimethoxy(methyl)silane (combined cis and trans isomers)
The predicted half-lives for degradation of Constituents 1a and 1b are ≤5.5 h at pH 7, ≤0.3 h at pH 4 and ≤0.1 h at pH 9 and 20-25°C. The QSAR method has been developed for alkoxysilanes. Constituents 1a and 1b contain a 1-[(2-ethylhexyl)oxy]propenyloxy group (as well as the two methoxy groups). There are no substances in the training set with this, or similar groups. This Si-OR’ group is expected to hydrolyse more rapidly than a similarly sized alkoxy group because both the carbon-carbon double bond and the second oxygen would weaken the Si-O bond electronically. This would speed up the hydrolysis. In addition, this group has some structural similarity with Si-carboxylate type structures that hydrolyse very rapidly. Therefore, the hydrolysis half-lives are reported as less than or equal to the predicted values.
The hydrolysis products are methylsilanetriol (1 mole), 1-[(2-ethylhexyl)oxy]prop-1-en-1-ol (1 mole) and methanol (2 moles). The 1-[(2-ethylhexyl)oxy]prop-1-en-1-ol formed by the hydrolysis of the Si-O bond undergoes tautomerism. This results in rearrangement of the enol-type structure to give the stable ester, 2-ethylhexyl propanoate. In the long-term, the hydrolysis product, 2-ethylhexyl propanoate may undergo further degradation/hydrolysis to the corresponding alcohol and acid; 2 -ethylhexylalcohol and propionic acid. This is supported by the observation made in a ready biodegradation study (Sudo 1995) where the products of degradation were reported as methylsilanetriol, propionic acid, methanol and 2-ethylhexylalcohol within the time scale of the study (28 days). The hydrolysis half-life is not known but this is expected to be slow at standard environmental temperature and pH (Mabey W and Mill T, 1978).
Therefore, the properties of 2-ethylhexyl propanoate, methanol and methylsilanetriol are considered in the chemical safety assessment.
Constituent 2: 2-ethylhexyl-3-[dimethoxy(methyl)silyl]propanoate
The predicted half-lives for degradation of Constituent 2 are 1.6 h at pH 7, 0.1 h at pH 4 and 0.03 h at pH 9 and 20-25°C.
The hydrolysis products are 2-ethylhexyl-3-[dihydroxy(methyl)silyl]propanoate (1 mole) and methanol (2 moles).
Reference:
Mabey W and Mill T, Critical review of hydrolysis of organic compounds in water under environmental conditions, J. Phys. Chem. Ref. Data, Vol. 7, No. 2, 383-415, 1978.
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.
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