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Vapour pressure

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Description of key information

The vapour pressure of THPS dry active substance 100% was determined by the balance method, according to standard methods under GLP and was set below 0.00026 Pa at 20°C and 25°C.
The vapour pressure of THPS 75% aqueous solution was determined according to standard methods under GLP using an isoteniscope. However this study had been disregarded because it was assessed that the results were mainly driven by the vapour pressure of water predominant in the test material.

Key value for chemical safety assessment

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

Additional information

The vapour pressure of THPS dry active substance (100%) was determined by the vapour pressure balance method, according OECD 104, EEC method A4 and US EPA/FIFRA subdivision D § 63 -9 guidelines, under GLP.

A sample of THPS was degassed under vacuum and a series of measurements made below and in the middle of the melting point range of the test material (20.0 to 78.9°C).The sample did not visibly appear to have suffered any decomposition at the temperatures used.

The following values were obtained:

Vp (20.0 °C) < 2.6003 E-04 Pa
Vp (31.1 °C) < 2.6003 E-04 Pa
Vp (39.0 °C) = 2.6003 E-04 Pa
Vp (59.1 °C) = 9.1009 E-04 Pa
Vp (70.0 °C) = 2.9383 E-03 Pa
Vp (78.9 °C) = 1.0297 E-02 Pa

Because the values obtained traverse the melting range, extrapolation of  the vapour pressure/temperature relationship was not performed. 

Therefore only a limiting value can be quoted at 20 and 25°C:

Vp (20 and 25°C) of THPS dry active substance (100%) < 2.6e-04 Pa (2.0E-06 Torr).

The vapour pressure of THPS 75% aqueous solution (Tolcide PS 75) was determined according to OECD 104 guideline and ASTM method N° 2879 under GLP using a standard isoteniscope. However this study had been disregarded (reliability 3) because it was assessed that the vapour pressures results were mainly driven by the vapour pressure of water predominant in the test material.