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Physical & Chemical properties

Endpoint summary

Administrative data

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Additional information

Propane-1,2 -diol (monopropylene glycol) is a colourless, very hygroscopic liquid with a melting point below -20 ˚ C (Harlan Laboratories Ltd., 2010a) and a boiling point of 184 ºC at 100.32 Pa (Harlan Laboratories Ltd., 2010a). The relative density of monopropylene glycol is 1.03 at 20 ˚C (Harlan Laboratories Ltd., 2010a).

The vapour pressure of monopropylene glycol is 20 Pa at 25 °C (Harlan Laboratories Ltd., 2010b). Monopropylene glycol is fully miscible with water at 20˚C and pH = 7.1 -7.8 (Harlan Laboratories Ltd., 2010a).The octanol/water partition coefficient (log Pow) is -1.07 at 20.5 ˚C and pH = 6.2 -6.4 (Harlan Laboratories Ltd., 2010a). The surface tension of monopropylene glycol in 1.01 g/L aqueous solution at 21.5 °C is 71.6 mN/m, indicating that the substance is not surface-active.

Monopropylene glycol has a dynamic viscosity of 43.4 mPa · s at 25 °C (George and Sastry, 2003; Sastry and Patel, 2003).

The substance has a flash point of 104 °C (Harlan Laboratories Ltd., 2010b) . Based on this value, classification for flammable properties is not warranted in accordance with EU Directive 67/548/EEC and EU Classification, Labeling and Packaging of Substances and Mixtures (CLP) Regulation (EC) No. 1272/2008. The auto-ignition temperature of monopropylene glycol is above 400 °C at 100.01-101.44 kPa (Harlan Laboratories Ltd., 2010b).The substance is not expected to have explosive and oxidising properties, therefore classification in accordance with EU Directive 67/548/EEC and 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.