Registration Dossier

Physical & Chemical properties

Vapour pressure

Currently viewing:

Administrative data

Link to relevant study record(s)

Referenceopen allclose all

Endpoint:
vapour pressure
Type of information:
(Q)SAR
Adequacy of study:
supporting study
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
results derived from a valid (Q)SAR model and falling into its applicability domain, with adequate and reliable documentation / justification
Justification for type of information:
See attached QMRF/QPRF
Principles of method if other than guideline:
The model is a fragment based algorithm for the prediction of vapour pressure of alkanes. It is based on an earlier unpublished model. The model is compared to the existing SRC model MPBPVP v1.43 which is a component of the EPISuite v4.11 (EPISUITE 2012).
Test no.:
#1
Temp.:
25 °C
Vapour pressure:
>= 0.002 - <= 11.5 Pa
Remarks on result:
other: The individual constituents of the substance have predicted vapour pressure values in the range 3.7E-03 to 11.5 Pa at 25°C

Table 1: Predicted vapour pressure for the individual constituents for linear and branched alkanes of C15-C19.

Carbon

Number

CH3

CH2

branched

 

SMILEs1

log VP (Pa)2

VP (Pa)

13

2

11

0

CCCCCCCCCCCCC

0.96

9.14E+00

13

3

9

1

CCCCCC(C)CCCCCC

1.06

1.15E+01

13

3

8

2

CCC(CC(C)C)CCCCCC

1.031

1.07E+01

14

2

12

0

CCCCCCCCCCCCCC

0.48

2.99E+00

14

3

10

1

CCCCCC(C)CCCCCCC

0.575

3.76E+00

14

3

9

2

CCC(CC(C)C)CCCCCCC

0.546

3.52E+00

15

2

13

0

CCCCCCCCCCCCCCC

-0.01

9.79E-01

15

3

11

1

CCCCCC(C)CCCCCCCC

0.09

1.23E+00

15

3

10

2

CCC(CC(C)C)CCCCCCCC

0.061

1.15E+00

16

2

14

0

CCCCCCCCCCCCCCCC

-0.49

3.21E-01

16

3

12

1

CCCCCC(C)CCCCCCCCC

-0.395

4.03E-01

16

3

11

2

CCC(CC(C)C)CCCCCCCCC

-0.424

3.77E-01

17

2

15

0

CCCCCCCCCCCCCCCCC

-0.98

1.05E-01

17

3

13

1

CCCCCC(C)CCCCCCCCCC

-0.88

1.32E-01

17

3

12

2

CCC(CC(C)C)CCCCCCCCCC

-0.909

1.23E-01

18

2

16

0

CCCCCCCCCCCCCCCCCC

-1.46

3.44E-02

18

3

14

1

CCCCCC(C)CCCCCCCCCCC

-1.365

4.32E-02

18

3

13

2

CCC(CC(C)C)CCCCCCCCCCC

-1.394

4.04E-02

19

2

17

0

CCCCCCCCCCCCCCCCCCC

-1.95

1.12E-02

19

3

15

1

CCCCCC(C)CCCCCCCCCCCC

-1.85

1.41E-02

19

3

14

2

CCC(CC(C)C)CCCCCCCCCCCC

-1.879

1.32E-02

20

2

18

0

CCCCCCCCCCCCCCCCCCCC

-2.43

3.68E-03

20

3

16

1

CCCCCC(C)CCCCCCCCCCCCC

-2.335

4.62E-03

20

3

15

2

CCC(CC(C)C)CCCCCCCCCCCCC

-2.364

4.33E-03

21  17   CCCCCC(C)CCCCCCCCCCCCCC -2.82  1.51E-03 

 

1Only a single possible isomer is represented for branched compounds

2The VP is not dependent of the location of any branch point in the molecule.

Conclusions:
The individual constituents of the substance have predicted vapour pressure values in the range 1.51E-03 to 11.5 Pa at 25°C using a validated QSAR estimation method. The result is considered to be reliable.
Endpoint:
vapour pressure
Type of information:
experimental study
Adequacy of study:
key study
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
guideline study with acceptable restrictions
Remarks:
The study was conducted in accordance with relevant test method but not in compliance with GLP.
Qualifier:
according to guideline
Guideline:
OECD Guideline 104 (Vapour Pressure Curve)
Deviations:
not specified
GLP compliance:
no
Type of method:
dynamic method
Key result
Test no.:
#1
Temp.:
20 °C
Vapour pressure:
0.04 Pa
Key result
Test no.:
#2
Temp.:
25 °C
Vapour pressure:
0.08 Pa
Key result
Test no.:
#3
Temp.:
50 °C
Vapour pressure:
1.5 Pa

Table 1: Experimental vapor pressure data for GTL Solvent GS 270

T / K

Pexp/ kPa

Pcalc/ kPa

1-Pexp/Pcalc

393.46

0.291

0.294

0.87%

396.79

0.352

0.353

0.29%

401.35

0.450

0.452

0.33%

405.14

0.556

0.550

-1.12%

409.14

0.679

0.674

-0.69%

413.48

0.842

0.835

-0.74%

418.81

1.09

1.08

-1.16%

424.19

1.37

1.38

0.82%

428.24

1.65

1.65

0.45%

432.50

1.98

1.99

0.54%

440.99

2.84

2.84

0.12%

447.87

3.75

3.73

-0.45%

452.47

4.47

4.45

-0.33%

460.92

6.11

6.09

-0.39%

468.15

7.89

7.85

-0.48%

476.45

10.43

10.39

-0.38%

484.71

13.60

13.56

-0.31%

494.63

18.33

18.37

0.18%

505.70

25.20

25.31

0.44%

516.14

33.55

33.68

0.39%

523.91

41.05

41.28

0.56%

532.63

50.78

51.37

1.15%

542.76

65.04

65.50

0.71%

552.10

81.49

81.12

-0.46%

560.70

99.57

97.97

-1.63%

 

Antoine parameters fitted to the experimental data are shown in Table 2

 

Table 2: Antoine parameters of the pure components:

 

DDB format: log (P/Torr) = A – B / (C + T/°C)

component

A

B

C

GTL Solvent GS 270

6.98164

1810.9

152.481

 

Aspen format: ln (P/Torr) = A + B / (C + T/°C)

component

A

B

C

GTL Solvent GS 270

16.0758

-4169.75

152.481

 

From the equations above, the author of the EPSR estimated the following vapour pressure values for the substance.

DDB Method

Temp (°C)

log p (torr)

VP (torr)

VP (Pa)

20

-3.51749

0.000304

4.0E-02

25

-3.22171

0.0006

8.0E-02

30

-2.94213

0.001143

1.5E-01

40

-2.42656

0.003745

5.0E-01

50

-1.96192

0.010917

1.5E+00

 

Aspen Method

Temp (°C)

ln p (torr)

VP (torr)

VP (Pa)

20

-8.09933

0.000304

4.0E-02

25

-7.41826

0.0006

8.0E-02

30

-6.77452

0.001143

1.5E-01

40

-5.58738

0.003745

5.0E-01

50

-4.51749

0.010916

1.5E+00

 

 

 

 

 

 

 

 

 

 

 

 

Conclusions:
Vapour pressure values of 0.04 Pa, 0.08 Pa and 1.5 Pa at 20°C, 25°C and 50°C respectively were determined for the substance using a relevant test method. The result is considered reliable.

Description of key information

Vapour pressure (whole substance): 0.04 Pa, 0.08 Pa and 1.5 Pa at 20°C, 25°C and 50°C respectively (measured).

Vapour pressure (individual constituents): 1.5E-03 to 11.5 Pa at 25°C (QSAR).

Key value for chemical safety assessment

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

Additional information

Vapour pressure values of 0.04 Pa, 0.08 Pa and 1.5 Pa at 20°C, 25°C and 50°C respectively were determined for the substance using the dynamic method in accordance with OECD 104 test method. The measurements were made at several temperatures (120.31 to approximately 288°C), therefore linear regression analysis was used to calculate the vapour pressures at 20°C, 25°C and 50°C. The result is considered to be reliable and is selected as key study.

Since the submission substance is a UVCB substance, the vapour pressures of the individual constituents are also important. Measured vapour pressure for the whole substance is preferred for the purpose of human health exposure assessment while the vapour pressures of individual constituents are useful for environmental risk characterisation.

This endpoint can be characterised using quantitative structure property relationships for representative hydrocarbon structures that comprise the hydrocarbon blocks used to assess the environmental risk of this substance with QSAR software (see Section 13).

As supporting information, the vapour pressures of the individual constituents were determined using a validated QSAR estimation method. Vapour pressure values in the range 1.5E-03 to 11.5 Pa at 25°C were determined for the constituents of the submission substance.