Registration Dossier

Physical & Chemical properties

Endpoint summary

Administrative data

Description of key information

Additional information

Dicumyl peroxide is an organic solid that is white in colour. It is described as a granular substance or as a free-flowing, crystalline solid.

The melting temperature for dicumyl peroxide ranges from 39 to 40.6 °C.

According to REACH Annex VII, the boiling point does not need to be determined because dicumyl peroxide decomposes before boiling.

The average density of dicumyl peroxide is 1.107 g/mL at 20 °C.

The approximate particle sizes L50, L90, and L10 of dicumyl peroxide are 1700 µm, 900 µm, and 6200 µm, respectively.

Vapour pressure for dicumyl peroxide ranges from less than 0.1 mbar for the temperatures 60–80 °C, to 1.53 mbar at 120 °C. The relevant vapour pressure to be used in the risk assessment is < 0.001 Pa at 25 °C.

The log Pow of dicumyl peroxide is 5.6 at 25 °C based on the HPLC method.

Water solubility is low (0.43 mg/L at 20 °C).

Data on surface tension for dicumyl peroxide does not need to be reported because according to REACH Annex VII 7.6, column 2, as surface activity is not expected based on structure of the substance. Furthermore, water solubility is below 1 mg/L at 20 °C.

According to REACH Annex VII, 7.12, column 2, a study on auto flammability does not need to be conducted as dicumyl peroxide is a solid with a melting point of less than 160 °C.

According to REACH Annex VII, 7.13, column 2, a study on oxidising properties does not need to be conducted, as the substance is an organic peroxide.

The substance has no explosive properties because it is not classified as Organic Peroxide Type B.

The substance is marketed as a solid and is not designed to be placed on the market in organic solvents.

According to REACH Annex XI, 1., a study for determination of the dissociation constant is scientifically unjustified as the substance has no functional groups that are susceptible to dissociation.

According to REACH Annex XI, 2., a study for the determination of the viscosity of dicumyl peroxide is technically not feasible, since the substance is a solid at room temperature.