Reaction mass of Disodium decyl(sulphonatophenoxy)benzenesulphonate and Disodium oxybis[decylbenzenesulphonate]

Vapour pressure

Link to relevant study record(s)

Reference

Endpoint:

vapour pressure

Type of information:

experimental study

Adequacy of study:

key study

Study period:

September 30, 2016 to December 19, 2016

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

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:

yes

Type of method:

effusion method: vapour pressure balance

Specific details on test material used for the study:

Identity: EC# 915-640-4
Physical state: White powder
Storage conditions: Room temperature (15 to 25°C)
Batch number: YY00F3RL01-Dry
Purity: Mixture
Expiry date: 28 June 2017

Key result

Test no.:

#1

Temp.:

25 °C

Vapour pressure:

0 Pa

Once degassing and/or removal of volatile impurities was complete, only slight deflections of the microbalance were obtained at the upper end of the temperature range investigated. This being the case, a maximum vapour pressure was calculated based on a series of deflection readings at this temperature (190.5˚C). Allowing for baseline noise on the chart recorder, the mass difference caused by sample vapour at 190.5°C was 0.70 μg (mean value of five determinations). Using equation 1, this equates to a vapour pressure of 1.2 x 10^-3 Pa at 190.5°C.

To calculate a value for the vapour pressure at 25°C, the regression line from a plot of log₁₀V_p versus 1/T was extrapolated from 190.5°C back to 25°C. To allow this, as it was not possible to obtain a satisfactory response at further temperatures below 190.5˚C (and thus enable a log₁₀V_p versus 1/T curve to be generated), a slope of –1000 was applied. This is the shallowest slope obtained historically at this laboratory, and provides a maximum vapour pressure for safety evaluation purposes. The equation used is as follows:

Log₁₀V_p1 – log₁₀V_p2 = slope(1/T₁ – 1/T₂)

Where:

V_p1 and T₁ are the vapour pressure and temperature (K), respectively, at 25°C

V_p2 and T₂ are the vapour pressure and temperature (K), respectively, at 190.5°C

Thus, log₁₀V_p1 = -1000 (1/298.15 – 1/463.65) + log₁₀(1.2 x 10^-3)

= -4.14

Hence V_p1 = 7.3 x 10^-5 Pa

The maximum vapour pressure at 25°C is therefore 7.3 x 10^-5 Pa.

Conclusions:

EC# 915-640-4 was found to have a maximum vapour pressure of 7 x 10^-5 Pa at 25°C.

Executive summary:

The vapour pressure of the test material was determined using a vapour pressure balance. A quantity of test substance (0.25 g) was added to the furnace, the apparatus assembled and evacuated to a pressure of less than 1 x 10^-5 Torr (1.3 x 10^-3 Pa). After stabilisation at a given temperature, the shutter was opened to allow a stream of vapour to impact upon one balance pan. The temperature and pan deflection were recorded on a chart recorder. The trace obtained enabled the calculation of mass difference. The furnace temperature was then raised in steps of approximately 5ºC and further measurements taken. Initial runs were disregarded, the high and variable results being indicative of degassing and/or removal of volatile impurities. Once degassing and/or removal of volatile impurities was complete, only slight deflections of the microbalance were obtained at the upper end of the temperature range investigated. The mass difference was, therefore, determined from a series of readings at this temperature to enable a limit value to be established. Based on the calculations, EC# 915-640-4 was found to have a maximum vapour pressure of 7 x 10^-5 Pa at 25°C.

Description of key information

EC# 915-640-4 was found to have a maximum vapour pressure of 7 x 10^-5 Pa at 25°C.

Key value for chemical safety assessment

Vapour pressure:

0 Pa

at the temperature of:

25 °C