Registration Dossier

Administrative data

Endpoint:
vapour pressure
Type of information:
experimental study
Adequacy of study:
key study
Study period:
5th March 1993 to 1st October 1993
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: Study conducted in compliance with agreed protocols, with no or minor deviations from standard test guidelines and/or minor methodological deficiencies, which do not affect the quality of the relevant results.

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1993
Report Date:
1993

Materials and methods

Test guidelineopen allclose all
Qualifier:
according to
Guideline:
EU Method A.4 (Vapour Pressure)
Deviations:
no
Qualifier:
according to
Guideline:
OECD Guideline 104 (Vapour Pressure Curve)
Deviations:
no
Principles of method if other than guideline:
The vapour pressure (A4) was performed according to the gas saturation method instead of one of the three methods described in the protocol-Directive EEC 92/69 was followed, instead of EEC 84/449 (update).
GLP compliance:
yes (incl. certificate)
Type of method:
gas saturation method

Test material

Reference
Name:
Unnamed
Type:
Constituent

Results and discussion

Vapour pressureopen allclose all
Temp.:
373.15 K
Vapour pressure:
0.796 other: mPa
Temp.:
363.15 K
Vapour pressure:
0.555 other: mPa
Temp.:
298.15 K
Vapour pressure:
0 Pa
Remarks on result:
other: 25 °C value calculated from above first two measurements
Transition / decomposition
Transition / decomposition:
no

Any other information on results incl. tables

The vapour pressure of a substance is defined as the saturation pressure of the vapour at thermodynamic equilibrium with the solid or liquid phase of the substance at a fixed temperature of the entire system. The vapour pressure so defined is a function of temperature only. The SI unit of pressure is the Pascal (Pa).

 

The vapour pressure, Vp, is related to the observed saturated gas concentration by the relationship:

 

Vp = (Weight of TA vaporised (g) x Temperature (K) x 8.314) / (Volume of saturated gas (m3) x Molecular weight) Pa

 

The vapour pressure-temperature relationship is represented as thedependence of log10vapour pressure versus reciprocal temperature in Kelvin, as expressed in the Clausius-Clapeyron equation. The linearity of such a representation stems from the relative insensitivity of heats of vaporisation/sublimation to temperature changes. The following vapour pressure relationship:

 

Log10Vp (Pa) = (Slope / Intercept Temperature (K)) + Intercept

 

is thus used to determine, by extrapolation, the vapour pressure at298.15K (25°C).

 

The slope and intercept of the vapour pressure curve are estimated byan unweighed least squares statistical treatment of all the data points.

 

The following were the mean determined vapour pressures:

 

Vp 100°C:                                                0.796 mPa

Vp 90°C:                                                  0.555 mPa

 

The derived line of Log10Vp (Y) against 1/T(K) (X) was determined from the 5 individual results:

 

Mean: Y = -4401.1 x1/T + 8.852. Correlation coefficient -0.857

 

Temperature 100 °C

Run time 191 hours

Channel reference

1

2

3

4

Nominal flow (mL/min)

17

23

28

32

Total sampled flow (mL)

192253

259001

316887

273242

Mass Millad 3988 collected (µg)

35.4

*

40.0

2.28

Vapour pressure (mPa)

1.38

*

0.945

0.063

Mean Vp (mPa)

0.796

 

* No sample detected

 

 

 

Temperature 90 °C

Run time 138 hours

Channel reference

1

2

3

4

Nominal flow (mL/min)

17

23

28

32

Total sampled flow (mL)

140524

189948

230962

266843

Mass Millad 3988 collected (µg)

*

16.3

20.8

14.1

Vapour pressure (mPa)

*

0.624

0.656

0.386

Mean Vp (mPa)

0.555

 

* No sample detected

Applicant's summary and conclusion

Conclusions:
The vapour pressure values at a range of temperatures were as shown below:
Vp = 0.796 mPa at 373.15 K
Vp = 0.555 mPa at 363.15 K
The calculated value of vapour pressure based upon the above readings is:
Vp = 1.23 x 10E-6 Pa at 298.15 (25 °C)
Executive summary:

In a vapour pressure study (13193), the vapour pressure of the test material was calculated to be 1.23 x 10E-6 Pa at 25 °C, according to Method A4 of Commission Directive 92/69/EEC.