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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:
04 May to 17 August 2012
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: see 'Remark'
Remarks:
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. The study report was conclusive, with experiments conducted according to appropriate and valid guidelines and conducted under GLP conditions.
Qualifier:
according to guideline
Guideline:
EU Method A.4 (Vapour Pressure)
Deviations:
no
Qualifier:
according to guideline
Guideline:
OECD Guideline 104 (Vapour Pressure Curve)
Deviations:
no
Qualifier:
according to guideline
Guideline:
EPA OPPTS 830.7950 (Vapor Pressure)
Deviations:
no
GLP compliance:
yes
Type of method:
effusion method: by loss of weight or by trapping vaporisate
Key result
Temp.:
20 °C
Vapour pressure:
0.37 Pa
Remarks on result:
other: (2.8 x 10^-3 mm Hg)
Key result
Temp.:
25 °C
Vapour pressure:
0.7 Pa
Remarks on result:
other: (5.3 x 10^-3 mm Hg)

Table 1. Results of the Isothermal TGA Analysis

Temperature (ºC)

Weight loss (µg/min)

Vτ (g/cm²/h)

Log Vτ

Log Pτ

Pτ (Pa)

60

22.68

2.71 x 10-*

-2.57

1.54

35

22.76

2.72 x 10-*

-2.57

1.54

35

70

54.83

6.54 x 10-*

-2.18

1.98

95

55.34

6.61 x 10-*

-2.18

1.98

96

80

123.2

1.47 x 10-*

-1.83

2.38

240

126.4

1.51 x 10-*

-1.82

2.39

250

90

249.2

2.79 x 10-*

-1.53

2.73

540

256.5

3.06 x 10-*

-1.51

2.74

560

Table 2. Vapour Pressure of the Test Material

Temperature (ºC)

Log Pτ

Pτ (Pa)

Pτ (mm Hg)

20

-0.43

0.37

2.8 x 10-3

25

-0.15

0.70

5.3 x 10-3
Conclusions:
Under the conditions of the test, the vapour pressure of the test material was determined to be 0.37 Pa at 20ºC.
Executive summary:

The vapour pressure of the test material was determined using the effusion method; the study was performed in accordance with GLP and to the standardised guidelines OECD 104, EU method A.3 and EPA OPPTS 830.7950.

Under the conditions of the test, the vapour pressure was determined to be 0.37 Pa at 20ºC and 0.70 Pa at 25ºC.

Description of key information

The vapour pressure of 3,5-Dimethylpyrazole was determined to 0.37 Pa at 20ºC in a key study (Baltussen, 2012) performed according to OECD 104, EU method A.3 and EPA OPPTS 830.7950; all other sources have been provided as supporting data.

Key value for chemical safety assessment

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

Additional information

The vapour pressure of the test material has been addressed by providing one key study and one supporting study.

Baltussen (2012) has been provided as the key study, where the vapour pressure was determined to be 0.37 Pa at 20ºC and 0.70 Pa at 25ºC using the effusion method. The study was performed in line with GLP and standardised guidelines and had thus been assigned a reliability score of 1 using the principles for assessing data quality as set out in Klimisch (1997).

MPBVP v1.43 (2010) is a prediction based made by the QSAR EPISuite. The test material was predicted to have a vapour pressure of 2.79 Pa at 25ºC, which was calculated according to the Grain method. This report has been assigned a reliability score of 4, according to the principles of Klimisch (1997).