Registration Dossier
Registration Dossier
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EC number: 270-724-1 | CAS number: 68477-33-8 A complex combination of hydrocarbons from the distillation of saturated and unsaturated hydrocarbons usually ranging in carbon numbers from C3 through C6, predominantly butane and isobutane. It consists of saturated and unsaturated hydrocarbons having carbon numbers in the range of C3 through C4, predominantly isobutane.
Vapour pressure
Administrative data
Link to relevant study record(s)
Description of key information
Vapour pressure data were read across from the butene substances (2-methylpropene, but-1-ene and 2-butene) to members of the C4, high 1,3 -butadiene (≥ 0.1%) category. The vapour pressures ranged from 484 to 1160 kPa at 25°C.
Key value for chemical safety assessment
- Vapour pressure:
- 837.25 kPa
- at the temperature of:
- 25 °C
Additional information
Vapour pressure data were read across from the butene substances (2-methylpropene: 1160 kPa at 25°C, but-1-ene: 1100 kPa at 25°C and 2-butene: 484 to 605 kPa at 25°C) for members of the category. The data were taken from the CRC handbook (Lide 2008), which is peer reviewed and considered a reliable source. The substances are C4 hydrocarbons and have a similar structure to the members of the category C4, high 1,3 -butadiene (≥0.1%). Due to their similar structures, they can be predicted to have similar physico-chemical properties and so read across from the butene substances is considered acceptable. The vapour pressure ranged from 484 to 1160 kPa at 25°C, and this range is considered to be representative of category C4, high 1,3 -butadiene (≥0.1%).
The mean of the vapour pressure values for the category is 837.25 kPa at 25°C and this has been used to complete the 'key value for chemical safety assessment'.
In the ECETOC TRA, any substance with a vapour pressure higher than 10 kPa is assigned a transfer to air factor of 1 (i.e. 100%) and the substance is considered to be completely released to air instantly. This is exactly what would happen to butadiene if it was to leak or be released into the environment. Therefore the model's basic underlying assumption is applicable to our substance.
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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