Tetradecamethylhexasiloxane

Vapour pressure

Link to relevant study record(s)

Reference

Endpoint:

vapour pressure

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2013-11-11 to 2013-12-10

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

Remarks:

The study was conducted in accordance with a relevant test method and in compliance with a known quality system (ISO 9001:2008)

Qualifier:

according to guideline

Guideline:

OECD Guideline 104 (Vapour Pressure Curve)

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method A.4 (Vapour Pressure)

Deviations:

no

GLP compliance:

no

Other quality assurance:

other: ISO 9001:2008

Type of method:

effusion method: by loss of weight or by trapping vaporisate

Key result

Test no.:

#1

Temp.:

20 °C

Vapour pressure:

0.27 Pa

Key result

Test no.:

#2

Temp.:

30 °C

Vapour pressure:

0.74 Pa

Key result

Test no.:

#3

Temp.:

50 °C

Vapour pressure:

5.7 Pa

Raw data

Date (start and termination)	Time (start and termination)	Temperature [°C]	Weight cell 1 [g]	Weight cell 2 [g]	Weight cell 3 [g]	Weight cell 4 [g]
11.11.2013	11:15	20	38.81912	39.48480	37.76766	38.61726
12.11.2013	07:45	20	38.76384	39.42908	37.73134	38.57648
12.11.2013	07:45	30	38.76384	39.42908	37.73134	38.57648
12.11.2013	12:30	30	38.73104	39.39586	37.70656	38.54972
12.11.2013	12:30	50	38.73104	39.39586	37.70656	38.54972
12.11.2013	15:30	50	38.56656	39.23460	37.60229	38.42214

 

Calculation of loss of masses

Temperature [°C]	Period of time [sec]	Calculated loss of mass [mg]
		Cell 1	Cell 2	Cell 3	Cell 4	Average
20	73800	55.28	55.72	36.32	40.78	47.02
30	17100	32.8	33.22	24.78	26.76	29.39
50	10800	164.48	161.26	104.27	127.58	139.4

 

Temperature [°C]	Vapour pressure [Pa]
20	0.26812
30	0.73544
50	5.70227

 

Calculation of the reliance log p to 1/T

Temperature [°C]	log p [hPa]	1/T [K^-1]
20	-2.57167	0.003411
30	-2.13345	0.003299
50	-1.24395	0.003095
Formula of regression	log p [hPa] = -4212.44 1/T [1/K] + 11.78387

 

Results from calculation (formula of regression)

Estimated vapour pressure [hPa]	Temperature [°C]
0.00260	20
0.0560	50

 

Conclusions:

Vapour pressure values of 0.27 Pa at 20°C, 0.74 Pa at 30°C and 5.7 Pa at 50°C were determined for the substance in accordance with a relevant test method and in compliance with a known quality system (ISO 9001:2008). The result is considered to be reliable.

Description of key information

Vapour pressure: 0.27 Pa at 20°C, 0.74 Pa at 30°C and 5.7 Pa at 50°C (OECD 104)

Key value for chemical safety assessment

Vapour pressure:

0.27 Pa

at the temperature of:

20 °C

Additional information

Vapour pressure values of 0.27 Pa at 20°C, 0.74 Pa at 30°C and 5.7 Pa at 50°C were determined for the substance using an effusion method (Knudsen cell) in accordance with OECD Test Guideline 104 and in compliance with a known quality system (ISO 9001:2008). The result is considered to be reliable and is selected as key study.

This value is supported by a vapour pressure of 0.66±0.16 Pa at 25°C which was based on estimation correlating GC retention time with temperature. In a secondary source to which no reliability could be assigned, vapour pressure value of 1.2 Pa at 25°C was reported for the substance. The supporting study is in good agreement with the key study.