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EC number: 240-816-6 | CAS number: 16753-62-1
- 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
Endpoint summary
Administrative data
Description of key information
Read-across studies for skin irritation, conducted with trimethoxy(vinyl)silane and triethoxy(vinyl)silane found them not irritating to rabbit skin. Similarly, the studies for eye irritation conducted trimethoxy(vinyl)silane and triethoxy(vinyl)silane found them not irritating to rabbit eyes.
Key value for chemical safety assessment
Skin irritation / corrosion
Endpoint conclusion
- Endpoint conclusion:
- no adverse effect observed (not irritating)
Eye irritation
Endpoint conclusion
- Endpoint conclusion:
- no adverse effect observed (not irritating)
Respiratory irritation
Endpoint conclusion
- Endpoint conclusion:
- no study available
Additional information
No in vitro or in vivo skin and eye irritation data are available for the registered substance. Reliable data are therefore read across from related alkoxysilanes as weight of evidence for these endpoints.
In a skin irritation study with triethoxy(vinyl)silane (WIL, 1998), the test substance was concluded to be slightly irritating to the skin of rabbits. However, the observed irritation did not meet the criteria for classification under Regulation (EC) No 1272/2008. 3 rabbits per sex were treated with 0.5 ml of the neat test substance for 4 h. The mean scores (over 24, 48, and 72 h) were 0.9 for erythema and 0.1 for edema reactions. Desquamation was observed in 1/6 animals after 72 h and was fully reversible within 11 days. Erythema and edema reactions were fully reversible within 9 days and 48 h, respectively.
The trimethoxy(vinyl)silane study for skin irritation found the test material not irritating to the skin of rabbits (Consultox 1976). There were no signs of erythema or edema at any time point. The Primary Irritation Index was 0.0 so the test material was considered a non-irritant under these conditions.
In an eye irritation study with triethoxy(vinyl)silane (WIL, 1998), the test substance was not irritating to the eyes of rabbits. 2 male and 4 female rabbits were treated with 0.1 ml of the neat test substance and were observed up to 72 h. No washing was performed after treatment with the test substance. Minor (grade 1) conjunctival effects were observed in 6/6 animals at 1 h, in 2/6 animals at 24 h and in 1/6 animals at 48 h, but no corneal or iridial effects were observed. The mean score over 24, 48, and 72 h was 0.1 for conjunctivae and was fully reversible within 48 h. Chemosis mean score was 0.1 with a maximum grade of 1 and was fully reversible within 72 h.
The trimethoxy(vinyl)silane study for eye irritation found the test material not irritating to the eyes of rabbits (Hoechst 1991). The conjunctiva of the animals showed marked hyperaemia and redness and slight conjunctival swelling was evident. Irritation was only observed 30 - 60 minutes post application; all effects were reversible within 1 day.
READ-ACROSS JUSTIFICATION
To reduce animal testing REACH recommends to make use of a read-across approach where appropriate based on the high accordance in properties relevant for the specific endpoint. In the case of irritation the relevant properties are structural similarity as well as physical-chemical properties in the same range. In the following paragraphs the proposed read-across from trimethoxy(vinyl)silane and triethoxy(vinyl)silane to dimethoxy(methyl)vinylsilane is evaluated point by point.
A report considering read across for all endpoints is attached in Section 13.
Read-across hypothesis
The hypothesis is that source and target substances have similar toxicological properties because they are structurally similar and hydrolyse to similar silicon-containing hydrolysis products. The non-silanol hydrolysis products, methanol and ethanol, do not contribute to any adverse effects for irritation at the relevant concentrations based on publicly available information. This is discussed further below.
Read-across justification
The predicted hydrolysis half-lives of the registered substance, dimethoxy(methyl)vinylsilane, are 18.3 minutes at pH 7, <2 minutes at pH 2, and 0.7 minutes at pH 9, all at 25oC; at 37.5oC and at pH 7 and 2 the predicted half-lives are 0.1 hours and 5 seconds respectively. The products of hydrolysis are methylvinylsilanediol and methanol.
The read-across substance triethoxy(vinyl)silane has predicted hydrolysis half-lives at 20-25°C of 0.1 hours at pH 4, 0.2 hours at pH 5 and 0.02 hours at pH 9. As the hydrolysis reaction may be acid or base catalysed, the rate of reaction is expected to be slowest at pH 7 and increase as the pH is raised or lowered. The hydrolysis products are vinylsilanetriol and ethanol.
The read-across substance trimethoxy(vinyl)silane has predicted hydrolysis half-lives at 25°C of 0.1 hours at pH 7, 0.04 hours at pH 4, and 0.004 hours at pH 9. The hydrolysis products are vinylsilanetriol and methanol.
Therefore, the predicted half-lives for the registration and read-across substances at physiological pH are generally comparable so during exposure similar levels of parent and hydrolysis products will be present and so read-across from triethoxy(vinyl)silane and trimethoxy(vinyl)silane to dimethoxy(methyl)vinylsilane for irritation is valid.
Analogue approach justification
(a) Structural similarity
The registration and read-across substances are structurally similar and are members of an analogue group of methylvinyl silane substances. All contain a silicon atom to which is attached to a vinyl group which is identical for all three. The registered substance has two alkoxy groups bound to silicon, the read-across substances have three. For the registered substance the two alkoxy groups are methoxy, the read-across substance trimethoxy(vinyl)silane has three such groups, while for the other read-across substance triethoxy(vinyl)silane, the three alkoxy groups are ethoxy. All hydrolyse rapidly to produce the similar silicon-containing hydrolysis products, methylvinylsilanediol or vinylsilanetriol and methanol or ethanol.
(b) Similar physicochemical characteristics
The key physicochemical parameters are summarised below.
Table: Key physicochemical parameters
|
Target (registration substance) |
Source (read-across substance |
Source (read-across substance |
CAS number |
016753-62-1 |
000078-08-0 |
002768-02-7 |
EC number |
240-816-6 |
201-081-7 |
220-449-8 |
Chemical Name |
dimethoxy(methyl)vinylsilane |
triethoxy(vinyl)silane |
trimethoxy(vinyl)silane |
Molecular weight |
132.23 |
190.31 |
148.23 |
log Kow(parent) |
2.3 |
3 |
Not applicable |
log Kow(silicon-containing hydrolysis product) |
-0.1 |
-2.0 |
-2.0 |
Water solubility (parent) |
3000 mg/L |
930 mg/L |
3E+04 mg/L |
Water solubility (silicon-containing hydrolysis product) |
5E+05 mg/L |
1E+06 mg/L |
1E+06 mg/L |
Vapour pressure (parent) |
3000 Pa |
304 Pa |
1190 Pa |
Vapour pressure (silicon-containing hydrolysis product) |
2.1 Pa |
0.02 Pa |
0.02 Pa |
(c) Discussion of irritation properties of the non-silanol hydrolysis products
The non-silanol hydrolysis products, methanol and ethanol, do not contribute to any irritant effects at the relevant concentrations based on publicly available information.
Justification for selection of skin irritation / corrosion endpoint:
One study was conducted according to an appropriate guideline and in compliance with GLP, the other was well documented and meets generally accepted scientific principles, but was not conducted in compliance with GLP.
Justification for selection of eye irritation endpoint:
Studies were conducted according to an appropriate guideline and in compliance with GLP.
Justification for classification or non-classification
Based on the available read-across data from trimethoxy(vinyl)silane and triethoxy(vinyl)silane, dimethoxy(methyl)vinylsilane does not require classification for skin or eye irritation according to Regulation (EC) 1272/2008.
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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