Registration Dossier
Registration Dossier
Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.
The new ECHA CHEM database has been released by ECHA, and it now contains all REACH registration data. There are more details on the transition of ECHA's published data to ECHA CHEM here.
Use of this information is subject to copyright laws and may require the permission of the owner of the information, as described in the ECHA Legal Notice.
EC number: 219-863-1 | CAS number: 2554-06-5
Endpoint summary
Administrative data
Description of key information
Additional information
The registration substance has an average purity of >70% 2,4,6,8-tetramethyl-2,4,6,8-tetravinylcyclotetrasiloxane (Vi4-D4), with <20% 2,4,6,8,10-pentamethyl-2,4,6,8,10-pentavinylcyclopentasiloxane Vi5-D5 (CAS 17704-22-2; Impurity 1) and <10% 2,4,6-trimethyl-2,4,6-trivinylcyclotrisiloxane Vi3-D3 (CAS 3901-77-7; Impurity 2) present as impurities. For relevant endpoints, the 3 components are considered separately. The key data relate to the main constituent (Vi4-D4), and may be for this substance or an appropriate read-across. These key data are supported by data relating to the two impurities, Vi5-D5 and Vi3-D3.
This substance has theoretically four geometric isomers. It has not been possible to separate these isomers and no differences in physicochemical properties have been observed.
Vi4-D4 is a liquid at ambient temperature and pressure, with a measured melting point of -55.6°C and a predicted boiling point of 220°C. It has a measured density of 0.9875 g/cm3at 20°C, a predicted kinematic viscosity of 6.3 mm2/s at 20°C, and a measured vapour pressure of 93.5 Pa at 25°C. It has a measured auto-ignition temperature of 236°C, and is not explosive and not oxidising on the basis of structural examination.
The substance has a measured log Kowof 6.47 at 20°C and a measured water solubility of 0.0073 – 0.0088 mg/l (7.3 – 8.8 ppb) at 23°C. The substance is not surface active based on structural examination.
In contact with water,Vi4-D4 will hydrolyse moderately quickly with a predicted hydrolysis half-life of approximately 63 h at pH 7 and 20 - 25°C. The half-life is for degradation of the parent substance by ring-opening; full hydrolysis will take longer.The ultimate hydrolysis product is methylvinylsilanediol according to the following equation:
[Si(CH3)(CH=CH2)O]4+ 4H2O→ 4[(CH3)(CH=CH2)Si(OH)2]
The registration substance has an average purity of >70% Vi4-D4, with <20% 2,4,6,8,10-pentamethyl-2,4,6,8,10-pentavinylcyclopentasiloxane (Vi5-D5; CAS 17704-22-2; Impurity 1) and <10% 2,4,6-trimethyl-2,4,6-trivinylcyclotrisiloxane (Vi3-D3; CAS 3901-77-7; Impurity 2) present as impurities. The presence of these impurities is not expected to affect the overall hazard profile of the substance based on the available evidence. Predicted vapour pressures of 0.6 Pa and 67 Pa at 25°C, water solubilities of 9.1E-06 mg/l and 1.3E-01 mg/l at 20°C, and log Kowvalues of 9.0 and 6.7 at 20°C were determined for Vi5-D5 and Vi3-D3, respectively. The impurities hydrolyse in a similar manner to Vi4-D4 giving the same ultimate hydrolysis product, methylvinylsilanediol. The half-lives are approximately 1600 h for Vi5-D5 and 0.5 h for Vi3-D3.
The registration substance is not classified as flammable according to Regulation (EC) No.1272/2008, on the basis of a measured flash point (for the registration substance itself) of 88°C and predicted boiling points for Vi4-D4, Vi5-D5 and Vi3-D3 of 220°C, 270°C and 170°C, respectively. The registration substance has a measured auto-ignition temperature of 236°C. It is not explosive and not oxidising on the basis of structural examination.
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.
