Registration Dossier

Physical & Chemical properties

Vapour pressure

Currently viewing:

Administrative data

Link to relevant study record(s)

Reference
Endpoint:
vapour pressure
Type of information:
experimental study
Adequacy of study:
key study
Study period:
24 November 2015 to 9 September 2016
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Qualifier:
according to
Guideline:
OECD Guideline 104 (Vapour Pressure Curve)
Deviations:
no
GLP compliance:
yes (incl. certificate)
Type of method:
effusion method: Knudsen cell
Key result
Temp.:
20 °C
Vapour pressure:
0 Pa
Temp.:
25 °C
Vapour pressure:
0 Pa

The test was performed from 58 to 94 °C. The vapour pressure of the test material was 1.162×10^-4 Pa at 20 °C and 1.933×10^-4 Pa at 25 °C, extrapolated from the Ln VP vs 1/T graph.

The IR spectra for the tested, control and untested material revealed no differences, therefore the test material was considered stable for the duration of the test.

Table 1: Vapour Pressure (VP) Calculations

Temp (°C)

Crucible weight

Vapour Pressure

1/T (K-1)

Ln (VP)

Test 1 (mg)

Test 2 (mg)

Test 1 (Pa)

Test 2 (Pa)

Test 1

Test 2

58.0

55.381

56.701

9.403E-03

7.199E-03

3.020E-03

-4.667E+00*

-4.934E+00*

55.289

56.630

58.0

55.289

56.630

3.263E-03

4.971E-03

3.020E-03

-5.725E+00

-5.304E+00

55.261

56.587

58.0

55.261

56.587

2.748E-03

5.780E-03

3.020E-03

-5.897E+00

-5.153E+00

55.236

56.534

71.0

55.236

56.534

5.399E-03

1.050E-02

2.906E-03

-5.221E+00

-4.557E+00

55.186

56.436

82.0

55.186

56.436

1.636E-02

2.613E-02

2.816E-03

-4.113E+00

-3.645E+00

55.045

56.209

94.0

55.045

56.209

4.282E-02

8.228E-02

2.724E-03

-3.151E+00

-2.498E+00

54.696

55.533

*: Data excluded from the analysis, poor fit to graph

Table 2: Vapour Pressure (VP) Results

 

1/T vs Ln(VP)

 

Extrapolated VP (Pa)

Test

Slope

Intercept

Correlation

20 °C

25 °C

1

-8.877E+03

2.090E+01

2.090E+01

8.381E-05

1.393E-04

2

-8.912E+03

2.159E+01

-9.865E-01

1.486E-04

2.474E-04

 

Mean of Extrapolated Vapour Pressure

1.162E-04

1.933E-04

Conclusions:
Under the conditions of the study, the vapour pressure of the test material was determined to be 1.162×10^-4 Pa at 20 °C and 1.933×10^-4 Pa at 25 °C.
Executive summary:

The vapour pressure of the test material was investigated in a study which was performed under GLP conditions and in accordance with the standardised guideline OECD 104.

The experimental procedure followed the Knudsen cell effusion method. A small quantity of the test substance (nominally 7-9 mg) was placed in each of two weighed aluminium crucibles and a lid, with an orifice of a nominal 1 mm diameter (accurately measured), cold-welded on. The crucibles were weighed to an accuracy of 1 µg and placed in the apparatus, which was then evacuated to ultra-high vacuum. At set time intervals, the apparatus was brought to atmospheric pressure, the crucibles reweighed and the loss in mass of test substance from each calculated. The vapour pressure ¿ (Pa) was calculated using the Hertz-Knudsen relationship. Tests were conducted between 58 and 94 °C to ensure that test substance remained in the liquid phase throughout the test period. The vapour pressures at 20 °C and 25 °C were then extrapolated from the vapour pressure-temperature plots.

Under the conditions of the study, the vapour pressure of the test material was determined to be 1.162×10^-4 Pa at 20 °C and 1.933×10^-4 Pa at 25 °C.

Description of key information

Under the conditions of the study, the vapour pressure of the test material was determined to be 1.162×10^-4 Pa at 20 °C and 1.933×10^-4 Pa at 25 °C.

Key value for chemical safety assessment

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

Additional information

The vapour pressure of the test material was investigated in a study which was performed under GLP conditions and in accordance with the standardised guideline OECD 104. The study was assigned a reliability score of 1 in accordance with the criteria for assessing data quality set forth by Klimisch et al. (1997).

The experimental procedure followed the Knudsen cell effusion method. A small quantity of the test substance (nominally 7-9 mg) was placed in each of two weighed aluminium crucibles and a lid, with an orifice of a nominal 1 mm diameter (accurately measured), cold-welded on. The crucibles were weighed to an accuracy of 1 µg and placed in the apparatus, which was then evacuated to ultra-high vacuum. At set time intervals, the apparatus was brought to atmospheric pressure, the crucibles reweighed and the loss in mass of test substance from each calculated. The vapour pressure ¿(Pa) was calculated using the Hertz-Knudsen relationship. Tests were conducted between 58 and 94°C to ensure that test substance remained in the liquid phase throughout the test period. The vapour pressures at 20°C and 25°C were then extrapolated from the vapour pressure-temperature plots.

Under the conditions of the study, the vapour pressure of the test material was determined to be 1.162×10^-4 Pa at 20 °C and 1.933×10^-4 Pa at 25 °C.