Registration Dossier

Physical & Chemical properties

Endpoint summary

Currently viewing:

Administrative data

Description of key information

Additional information

Propylene oxide is a colourless liquid with a sweet, ether-like odour. It has a melting point of - 112 ˚C (Oetting et al., 1964) and a boiling point of 35 ºC (Harlan Laboratories Ltd., 2010a). The relative density of propylene oxide is 0.830 at 20 ˚C (Harlan Laboratories Ltd., 2010a).

The vapour pressure of propylene oxide is 74 kPa at 25 °C (Harlan Laboratories Ltd., 2010b). Water solubility of propylene oxide lies in a range of 42.5 -45.0% w/w (ca. 425-450 g/L) at 20˚C (Harlan Laboratories Ltd., 2010a). The octanol/water partition coefficient (log Pow) was determined by reverse-phase HPLC (Shell Research Limited, 1986) and calculated using the method of Hansch and Leo (1979) and is < 1. Propylene oxide has a static viscosity of 0.374 mm2/s at 20 °C and of 0.447 mm2/s at 0°C (Harlan Laboratories Ltd., 2010a). The substance is not surface active (surface activity of 1.06 g/L solution at 21 ˚ C is 71.5 mN/m) (Harlan Laboratories, 2010a).

The substance has a flash point of -38 °C (Harlan Laboratories Ltd., 2010b). Based on this value and a boiling point of 35 ºC, propylene oxide is classified as Cat. 1, H224 in EU Classification, Labeling and Packaging of Substances and Mixtures (CLP) Regulation (EC) No. 1272/2008.

Although the presence of 1,2 -epoxide in the structure of propylene oxide indicates potential explosive properties, the oxygen balance is -220, suggesting that the substance is non-explosive. Respectively, the testing is not warranted in accordance with Column 2 of REACH Annex XI and Chapter R.7.1.11.3 of REACH Guidance on information requirements and chemical safety assessment. Consequently, propylene oxide does not need to be classified as explosive in accordance with and EU Classification, Labelling and Packaging of Substances and Mixtures (CLP) Regulation (EC) No. 1272/2008.

The auto-ignition temperature of propylene oxide is > 400°C (Harlan Laboratories Ltd., 2010b).

The conductance of the study on oxidizing properties is not warranted in accordance with Column 2 of REACH Annex VII, based on the substance extreme flammability and its structure. Accordingly, the classification in accordance with EU Classification, Labelling and Packaging of Substances and Mixtures (CLP) Regulation (EC) No. 1272/2008 is not warranted.

The substance remains undissociated in water, as it does not contain chemical groups which can undergo dissociation.

In accordance with column 1 or 2 of REACH Annex VII/IX and/or with section 1 of REACH Annex XI and/or the REACH guidance on information requirements and chemical safety assessment (chapter R7.A), data on the particle size distribution, pyrophoricity, water reactivity and stability in organic solvents and identity of relevant degradation products do not need to be conducted.