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Vapour pressure

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

vapour pressure

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

EU Method A.4 (Vapour Pressure)

Deviations:

yes

Remarks:

OECD proposes a temperature range of 0 – 50 °C or 120 – 150 °C. This range was ex-tended in the experimental run as several test items were examined simultaneously, and other test items showed much lower or higher vapour pressures.

GLP compliance:

yes (incl. QA statement)

Type of method:

effusion method: by loss of weight or by trapping vaporisate

Key result

Temp.:

25 °C

Vapour pressure:

0.006 Pa

Remarks on result:

other: calculated from the regression equation

Temp.:

20 °C

Vapour pressure:

0.005 Pa

Remarks on result:

other: calculated from the regression equation

For the test item the following vapour pressures at 20 °C and at 25 °C were calculated from the regression equation. The linear regression of log p vs. 1/T gave a correlation coefficient r of - 0.879, showing medium repeatability and precision.

This is considered to be due to the test item’s properties (mixture of several compounds with different vapour pressures). Vapour pressure of mixtures can not be reasonably determined using a dynamic method (where test item composition changes in the course of the determination); but the static method is not suitable for test items with very low vapour pressures. The result of the test can be considered valid.

Conclusions:

For the test item the following vapour pressures at 20 °C and at 25 °C were calculated from the regression equation: 0.00513 Pa at 20 °C and 0.00628 Pa at 25 °C

Executive summary:

The vapour pressure of the substance was determined following the EU method A.4 by the effusion method (weight loss). For the test item the following vapour pressures at 20 °C and at 25 °C were calculated from the regression equation: 0.00513 Pa at 20 °C and 0.00628 Pa at 25 °C.(LAUS GmbH, 2010).

Reference 2

Endpoint:

vapour pressure

Type of information:

experimental study

Adequacy of study:

supporting study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 104 (Vapour Pressure Curve)

GLP compliance:

yes (incl. QA statement)

Type of method:

static method

Temp.:

20 °C

Vapour pressure:

< 20 Pa

Remarks on result:

other: measured

Temp.:

35 °C

Vapour pressure:

25.6 Pa

Remarks on result:

other: measured

Temp.:

55 °C

Vapour pressure:

66.5

Remarks on result:

other: measured

Temp.:

20 °C

Vapour pressure:

8.9 Pa

Remarks on result:

other: To reproduce the experimental data of the study the Clausius-Clapeyron equation was used for calculation.

Temp.:

25 °C

Vapour pressure:

12.8 Pa

Remarks on result:

other: To reproduce the experimental data of the study the Clausius-Clapeyron equation was used for calculation.

Because the vapour pressure measurements are made at (or at least near) ambient temperatures, the need to extrapolate data from high temperatures is not necessary.

Conclusions:

The value of the vapour pressure was below the limit of quantification of this equipment (< 20 Pa).Using the Clausius-Clapeyron equation and parameters determined to reproduce the experimental data of the study, the vapour pressure at 20 °C at 25 °C was calculated with 8.9 Pa and 12.8 Pa, respectively.

Executive summary:

The vapour pressure of the test item was determined experimentally by the static method (OECD 104) at 20 °C, 35 °C and 50 °C. Using the Clausius-Clapeyron equation and parameters determined to reproduce the experimental data of the study, the vapour pressure at 20 °C at 25 °C was calculated with 8.9 Pa and 12.8 Pa, respectively (Currenta, 2009).

Description of key information

The vapour pressure of the substance was determined following the EU method A.4 by the effusion method (weight loss).For the test item the following vapour pressures at 20 °C and at 25 °C were calculated from the regression equation: 0.00513 Pa at 20 °C and 0.00628 Pa at 25 °C.(LAUS GmbH, 2010).

Key value for chemical safety assessment

Vapour pressure:

0.006 Pa

at the temperature of:

25 °C