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Category name:
Linear Alpha Olefins

Justifications and discussions

Category definition:
The category applies to substances that are aliphatic olefin isomeric mixtures with a single double bond predominantly in the alpha position. Some branched isomers may also be present though the substances are expected to be greater than 50% linear. Substances in this category may contain either a single carbon number or a range of carbon numbers.
Category description:
Increasing Carbon chain length
Category rationale:

The Linear Alpha Olefins Category covers straight chain hydrocarbons with a single double bond predominantly in the alpha position. The carbon number of the chemicals in this category range from C6 to C 30. The category covers substances that are predominantly a single carbon number and substances that contain a range of carbon numbers (<8). All of the substances in this category are almost entirely olefinic.

The phys-chem and environmental fate properties of the category members will be very similar or if they change, they will change in a predictable fashion. For example, the water solubility of the category members is expected to decrease as the carbon number of the category members increases. Environmental effects will behave in a similar manner, acting via non-polar narcosis. It is expected that the water solubility will limit the aquatic toxicity of the higher carbon number substances. With regard to mammalian endpoints, category members C24 are waxy solids at room temperature. For a majority of the category members, dermal contact represents the primary route of exposure with inhalation expected to be only a minor or secondary source of exposure. The only possible exception would be C6 alpha olefin which has moderate volatility. The category members differ from one-another in the length of the carbon chain and or the range of carbon numbers. The differing carbon chain length is not anticipated to have a significant affect on the mammalian toxicity. It can therefore, be assumed that streams meeting the applicability domain will behave in a similar manner and that use of read-across is valid.