Phosphoric acid, 2-ethylhexyl ester

Vapour pressure

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

vapour pressure

Type of information:

experimental study

Adequacy of study:

key study

Study period:

Testing was conducted between 23 May 2011 and 23 June 2011.

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, done to a valid guideline and the study was conducted under GLP conditions.

Qualifier:

equivalent or similar to guideline

Guideline:

other: Testing was conducted using a procedure designed to be compatible with Method A4 Vapour Pressure of Commission Regulation (EC) No 440/2208 of 30 May 2008, and Method 104 specified in the OECD Guidelines for Testing of Chemicals, 23 March 2006.

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Type of method:

effusion method: vapour pressure balance

Temp.:

25 °C

Vapour pressure:

0.085 Pa

Transition / decomposition:

no

Summary of Results

Run	Log10[Vp(25ºC)]	Vapour Pressure at 25°C (Pa)
1	-1.069	8.5 x 10^-2
2	-1.109	7.8 x 10^-2
3	-1.139	7.3 x 10^-2
4	-1.172	6.7 x 10^-2
5	-1.193	6.4x 10^-2
6	-1.191	6.4 x 10^-2
7	-1.216	6.1 x 10^-2
8	-1.251	5.6 x 10^-2
9	-1.270	5.4 x 10^-2
10	-1.281	5.2 x 10^-2

The test item did not change in appearance under the conditions used in the determination.

Please see Attachment 2 for Graphs of Log10 vapour pressure vs Reciprocal Temp runs 1 -10 and Results tables in Attached background material section.

Conclusions:

The vapour pressure of the test item has been determined to be 8.5 x 10-2 Pa at 25ºC.

Executive summary:

Method

The vapour pressure was determined using a vapour pressure balance with measurents being made at several temperatures and linear regression analysis used to calculate the vapour pressure at 25°C. Testing was conducted using a procedure designed to be compatible with Method A4 Vapour Pressure of Commission Regulation (EC) No 440/2208 of 30 May 2008, and Method 104 specified in the OECD Guidelines for Testing of Chemicals, 23 March 2006.

Summary of results

Run	Log10[Vp(25ºC)]	Vapour Pressure at 25°C (Pa)
1	-1.069	8.5 x 10^-2
2	-1.109	7.8 x 10^-2
3	-1.139	7.3 x 10^-2
4	-1.172	6.7 x 10^-2
5	-1.193	6.4x 10^-2
6	-1.191	6.4 x 10^-2
7	-1.216	6.1 x 10^-2
8	-1.251	5.6 x 10^-2
9	-1.270	5.4 x 10^-2
10	-1.281	5.2 x 10^-2

Conclusion

The vapour pressure of the test item has been determined to be 8.5 x 10^-2 Pa at 25ºC.

Reference 2

Endpoint:

vapour pressure

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2011

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: GLP study according to OECD guideline 104

Qualifier:

according to guideline

Guideline:

OECD Guideline 104 (Vapour Pressure Curve)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Type of method:

effusion method: vapour pressure balance

Temp.:

20 °C

Vapour pressure:

0 Pa

Remarks on result:

other: The calculated vapor pressure is extrapolated

Temp.:

25

Vapour pressure:

0 Pa

Remarks on result:

other: The calculated vapor pressure is extrapolated

Temp.:

50 °C

Vapour pressure:

0.002 Pa

Thermal Stability

A DSC-measurement in closed glass crucible showed no thermal effects up to 200 °C

Vapour Pressure Balance (Effusion Method)

The vapour pressure was measured in the temperature range of 18 °C to 127 °C Above 62 °C a vapour pressure could be measured. The measured vapour pressures at the corresponding temperatures are listed in the following table:

 

Temperature/°C	Vapour pressure/hPa
62.0	4.1x10 ^-5
67.0	1.5x10 ^-4
70.2	1.8x10^-4
74.2	5.8x10 ^-4
78.3	1.8x10 ^-4
82.5	5.4x10 ^-4
87.3	6.1x10 ^-4
92.8	4.3x10 ^-4
98.2	9.2x10 ^-4
103.4	1.2x10^-3
109.4	2.1x10^-3
115.0	2.6x10^-3
121.0	6.3x10^-3

 

 As the test item is a mixture a mean molecular weight was assumed according to the composition given in the certificate of analysis for calculating the vapour pressure by the Knudsen-Hertz formula.

Conclusions:

The vapor pressure measured according to the OECD Guideline 104 for this substance is 0.00012 Pa at 20 °C

Executive summary:

The vapor pressure measured according to the OECD Guideline 104 for this substance is 0.00012 Pa at 20 °C

Description of key information

Vapour pressure = 0.085 Pa (25°C); Tremain & Atwal (2011); E.U. Method A.4.
Vapour pressure = 0.00012 Pa (20°C); Dornhagen (2011); OECD 104 (vapour pressure curve)

Key value for chemical safety assessment

Vapour pressure:

0.085 Pa

at the temperature of:

25 °C

Additional information

The overall endpoint determination of vapour pressure was conducted using a vapour pressure balance with measurements being made at several temperatures and linear regression analysis used to calculate the vapour pressure at 25°C. Testing was conducted using a procedure designed to be compatible with Method A4 Vapour Pressure of Commission Regulation (EC) No 440/2208 of 30 May 2008, and Method 104 specified in the OECD Guidelines for Testing of Chemicals, 23 March 2006.

A slight, but gradual drop in vapour pressure was observed on repeated temperature cycling of the test item over the range 20 to 30°C (under vacuum), with individual vapour pressure values in the range 8.5 x 10^-2 to 5.2 x 10^-2 Pa at 25°C for ten consecutive runs. Such vapour pressure characteristics, are indicative of the gradual reduction of a more volatile fraction of the test item.

To provide representative data for risk assessment on accidental release of the test item, the initial, highest value obtained has been taken as the definitive result since although the drift in observed vapour pressure was not significant, such characteristics prevented reporting of a definitive, mean value.