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Physical & Chemical properties

Vapour pressure

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Reference
Endpoint:
vapour pressure
Type of information:
experimental study
Adequacy of study:
key study
Study period:
from 2017-05-02 to 2017-06-01
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Reference:
Composition 0
Qualifier:
according to
Guideline:
OECD Guideline 104 (Vapour Pressure Curve)
Deviations:
no
Qualifier:
according to
Guideline:
EU Method A.4 (Vapour Pressure)
Deviations:
no
GLP compliance:
yes (incl. certificate)
Type of method:
effusion method: Knudsen cell
Test material information:
Composition 1
Key result
Temp.:
20 °C
Vapour pressure:
0.002 Pa
Temp.:
25 °C
Vapour pressure:
0.003 Pa
Remarks on result:
not measured/tested
Remarks on result:
not measured/tested

Table 1. Calculation Results Experiment 1

Experiment

1

 

 

 

 

 

 

 

 

Real Temperature in K

303.2

 

 

 

 

 

 

 

 

Real Temperature in °C

30.0

 

 

 

 

 

 

 

 

Date of Measurement

03.05.2017 11:40

04.05.2017 11:50

05.05.2017 11:45

Elapsed Time in s

82920

81600

82500

Parameter

Weight loss

to be used

Vapour pressure

Weight loss

to be used

Vapour pressure

Weight loss

to be used

Vapour pressure

Unit

g

yes/no

Pa

g

yes/no

Pa

g

yes/no

Pa

Knudsen-cell 1

0.00117

yes

4.14E-03

0.00130

yes

4.68E-03

0.00095

yes

3.38E-03

Knudsen-cell 2

0.00095

yes

3.36E-03

0.00133

yes

4.79E-03

0.00094

yes

3.35E-03

Knudsen-cell 3

0.00143

yes

5.06E-03

0.00132

yes

4.75E-03

0.00096

yes

3.42E-03

Knudsen-cell 4

0.00149

yes

5.28E-03

0.00140

yes

5.04E-03

0.00090

yes

3.20E-03

Mean

 

yes

4.46E-03

 

yes

4.81E-03

 

yes

3.34E-03

Standard deviation:

 

 

8.82E-04

 

 

1.57E-04

 

 

9.36E-05

Mean of measured values:

 

4.205E-03

 

 

 

 

 

 

Standard deviation:

 

7.713E-04

RSD:

18.3%

 

 

 

 

Table 2. Calculation Results Experiment 2

Experiment

2

 

 

 

 

 

 

 

 

Real Temperature in K

318.2

 

 

 

 

 

 

 

 

Real Temperature in °C

45.0

 

 

 

 

 

 

 

 

Date of Measurement

09.05.2017 11:50

10.05.2017 11:50

11.05.2017 11:40

Elapsed Time in s

85500

83100

82800

Parameter

Weight loss

to be used

Vapour pressure

Weight loss

to be used

Vapour pressure

Weight loss

to be used

Vapour pressure

Unit

g

yes/no

Pa

g

yes/no

Pa

g

yes/no

Pa

Knudsen-cell 1

0.00384

yes

1.35E-02

0.00351

yes

1.27E-02

0.00296

yes

1.08E-02

Knudsen-cell 2

0.00368

yes

1.29E-02

0.00340

yes

1.23E-02

0.00306

yes

1.11E-02

Knudsen-cell 3

0.00364

yes

1.28E-02

0.00335

yes

1.21E-02

0.00298

yes

1.08E-02

Knudsen-cell 4

0.00432

yes

1.52E-02

0.00382

yes

1.38E-02

0.00336

yes

1.22E-02

Mean

 

yes

1.36E-02

 

yes

1.27E-02

 

yes

1.12E-02

Standard deviation:

 

 

1.10E-03

 

 

7.63E-04

 

 

6.73E-04

Mean of measured values:

 

1.253E-02

 

 

 

 

 

 

Standard deviation:

 

1.209E-03

RSD:

9.7%

 

 

 

 

Table 3. Calculation Results Experiment 3

Experiment

3

 

 

 

 

 

 

 

 

Real Temperature in K

333.2

 

 

 

 

 

 

 

 

Real Temperature in °C

60.0

 

 

 

 

 

 

 

 

Date of Measurement

12.05.2017 12:10

16.05.2017 10:00

17.05.2017 10:45

Elapsed Time in s

84900

77400

82500

Parameter

Weight loss

to be used

Vapour pressure

Weight loss

to be used

Vapour pressure

Weight loss

to be used

Vapour pressure

Unit

g

yes/no

Pa

g

yes/no

Pa

g

yes/no

Pa

Knudsen-cell 1

0.01104

yes

4.00E-02

0.00688

yes

2.74E-02

0.00321

yes

1.20E-02

Knudsen-cell 2

0.01077

yes

3.91E-02

0.00653

yes

2.60E-02

0.00343

yes

1.28E-02

Knudsen-cell 3

0.01075

yes

3.90E-02

0.00657

yes

2.61E-02

0.00359

yes

1.34E-02

Knudsen-cell 4

0.01234

yes

4.47E-02

0.00834

yes

3.32E-02

0.00342

yes

1.28E-02

Mean

 

yes

4.07E-02

 

yes

2.82E-02

 

no

 

Standard deviation:

 

 

2.74E-03

 

 

3.40E-03

 

 

 

Mean of measured values:

 

3.443E-02

 

 

 

 

 

 

Standard deviation:

 

8.869E-03

RSD:

25.8%

 

 

 

 

If “no” is stated in the respective column: measurement was not considered for the calculation of the mean.

Experiment 4 (75 °C) showed no reproducible weight loss. Therefore, this experiment was not used for calculation and the measurement was stopped.

The following vapour pressures were determined experimentally and considered as valid (mean and standard deviation given):

 

Table 1: Experimentally Determined Vapour Pressures

T

T

P

Stand. Dev. P

RSD P

°C

K

Pa

Pa

%

30.0

303.2

4.20E-03

7.71E-04

18.3%

45.0

318.2

1.25E-02

1.21E-03

9.7%

60.0

333.2

3.44E-02

8.87E-03

25.8%

In this table, E-0X represents multiplication with 10-X.

Stand. Dev. = Standard Deviation; RSD = Relative Standard Deviation

The linear regression of log P vs. 1/T gave a correlation coefficient r of – 1.0000, showing good repeatability and precision. Therefore, the determination is considered as valid.

Parameter

Value

Slope

-3075.0

Intercept

7.7644

Correlation Coefficient r

-1.0000

Coefficient of Determination r2

1.0000

Conclusions:
For the test item the following vapour pressures at 20°C and at 25°C were calculated from the regression equation:
for 20 °C: 1.88 * 1E-03 Pa
for 25 °C: 2.82 * 1E-03 Pa
Executive summary:

A key study was performed according to OECD TG 104 and Regulation (EC) No 440/2008 method A.4 in order to determine the vapour pressure of the test item at four different temperatures (30, 45, 60 and 75 °C) by using the effusion (Knudsen cell) method. Three experiments could be evaluated as they showed relevant and reproducible weight loss. All evaluated experiments showed good reproducibility, giving relative standard deviations of less than 26 % and perfect correlation. The vapour pressure of the test item was determined to be 1.88 * 10-03 Pa (20 °C) and 2.82 * 10-03 Pa (25 °C). The results of the test were considered as valid.

Description of key information

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

for 20 °C: 1.88 * 10E-03 Pa

for 25 °C: 2.82 * 10E-03 Pa

Key value for chemical safety assessment

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

Additional information

A study was performed according to OECD TG 104 and Regulation (EC) No 440/2008 method A.4 in order to determine the vapour pressure of the test item at four different temperatures (30, 45, 60 and 75 °C) by using the effusion (Knudsen cell) method. All evaluated experiments showed good reproducibility, giving relative standard deviations of less than 26 % and perfect correlation. The vapour pressure of the test item was determined to be 1.88*10-03 Pa (20 °C) and 2.82*10-03 Pa (25 °C). The results of the test were considered as valid (reference 4.6-1).