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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:
2015-08-06
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
guideline study with acceptable restrictions
Remarks:
The study was conducted according to an appropriate OECD test guideline and in compliance with a known quality system (ISO 9001:2008).
Reference:
Composition 0
Qualifier:
according to
Guideline:
OECD Guideline 104 (Vapour Pressure Curve)
Qualifier:
according to
Guideline:
EU Method A.4 (Vapour Pressure)
GLP compliance:
no
Other quality assurance:
other: ISO 9001:2008
Type of method:
dynamic method
Test material information:
Composition 1
Key result
Test no.:
#1
Temp.:
20 °C
Vapour pressure:
0.06 hPa
Key result
Test no.:
#2
Temp.:
50 °C
Vapour pressure:
1.4 hPa

Raw data

Data point

Boiling temperature T [°C]

Vapour pressure p [hPa]

1

50

1.2

2

53

1.9

3

57

2.5

4

58

3.5

5

62

4.0

6

63.4

5.7

7

66.7

6.4

8

67.5

7.0

9

70.3

8.5

10

72.8

10.0

11

74.1

11.0

12

75.5

12.0

13

71.2

9.3

14

67.2

7.4

15

62.7

5.2

16

58.2

3.5

17

54.5

2.4

18

50.4

1.4

19

47.1

0.9

 

Conversion of raw data

Data point

T [K]

1/T [1/K]

Log p [hPa]

1

323.15

0.003095

0.07918

2

326.15

0.003066

0.27875

3

330.15

0.003029

0.39794

4

331.15

0.003020

0.54407

5

335.15

0.002984

0.60206

6

336.55

0.002971

0.75587

7

339.85

0.002942

0.80618

8

340.65

0.002936

0.84510

9

343.45

0.002912

0.92942

10

345.95

0.002891

1.00000

11

347.25

0.002880

1.04139

12

348.65

0.002868

1.07918

 

Results from calculation

Estimated vapour pressure*

Temperature

0.06 hPa

20°C

1.4 hPa

50°C

*The estimated values were calculated using the formula of regression.

Formula of regression: log p [hPa] = -4355.06 1/T [1/K] + 13.62371

Conclusions:
Measured vapour pressure values of 0.06 hPa at 20°C and 1.4 hPa at 50°C were determined for the substance in accordance with OECD 104 Test Guideline and in compliance with a known quality system (ISO 9001:2008). The result is considered to be reliable.

Description of key information

Vapour pressure [ 1,1-dimethyl-N,N'-bis(1-methylpropyl)silanediamine]: 0.06 hPa at 20°C and 1.4 hPa at 50°C (EU Method A.4)

Vapour pressure [dimethylsilanediol]: 7 Pa at 25°C (QSAR)

Vapour pressure [sec-butylamine]: ca. 24000 Pa at 25°C

Key value for chemical safety assessment

Vapour pressure:
0.06 hPa
at the temperature of:
20 °C

Additional information

Measured vapour pressure values of 0.06 hPa at 20°C and 1.4 hPa at 50°C were determined for the submission substance in accordance with EU Test Method A.4 and in compliance with a known quality system (ISO 9001:2008). The result is considered to be reliable and is selected as key study.

In contact with water, the submission substance hydrolyses very rapidly to form dimethylsilanediol (CAS No. 1066-42-8) and sec-butylamine (CAS No. 13952-84-6).

The vapour pressure of the silanol hydrolysis product, dimethylsilanediol was predicted to be 7 Pa at 25°C using a validated QSAR estimation method.

A vapour pressure of approximately 24000 Pa at 25°C was reported for sec-butylamine (Daubert and Danner 1989).

Reference:

Daubert, T.E., R.P. Danner (1989). Physical and Thermodynamic Properties of Pure Chemicals Data Compilation. Washington, D.C.: Taylor and Francis