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Physical & Chemical properties

Vapour pressure

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Description of key information

The vapour pressure of Mecoprop-P n-octyl ester is 0.00061 Pa at 20 °C.

Key value for chemical safety assessment

Vapour pressure:
0.001 Pa
at the temperature of:
20 °C

Additional information

The vapour pressures of Mecoprop-P n-octyl ester were measured using the Knudsen effusion method (decrease of mass), according to the guidelines OECD 104 / EU A.4.

Experiments were performed at six temperatures between 50 °C and 100 °C. The results permit the establishment of the relation between the vapour pressure of the compound and temperature, allowing the knowledge of the vapour pressure of the compound at different temperatures.

Based on the results, the vapour pressure of the compound was calculated to be 0.00061 Pa at 20°C, 0.0012 Pa at 25°C and 0.027 Pa at 50°C. These vapour pressure values were extrapolated from the experimental data.

In a further study a vapour pressure of 0.00285 Pa was determined. Measurements were performed between 35.02 and 79.90°C.

The vapour pressure of Mecoprop-P n-octyl ester is given by the following equation, recommended for the temperature range from approx.10 °C to 70 °C. Outside this temperature range, it is expected that the equation will progressively produce values that are higher than the real vapour pressure of the compound.


p = exp(-9362.6 / T + 26.076)


Where p is the vapour pressure in Pa and T is the temperature in Kelvin.