2-[[4-[ethyl(2-hydroxyethyl)amino]phenyl]azo]-6-methoxy-3-methylbenzothiazolium methyl sulphate

Vapour pressure

Link to relevant study record(s)

Reference

Endpoint:

vapour pressure

Type of information:

read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

key study

Justification for type of information:

For justification of read-across please refer to the read-across report attached to IUCLID section 13.

Reason / purpose for cross-reference:

read-across source

Key result

Test no.:

#1

Temp.:

20 °C

Vapour pressure:

< 0 Pa

Key result

Test no.:

#2

Temp.:

25 °C

Vapour pressure:

< 0 Pa

Key result

Test no.:

#3

Temp.:

50 °C

Vapour pressure:

< 0 Pa

Conclusions:

As all measured values were below the detection limit of the method, the following uppper limit vapour pressure for the test item were calculated: <1.3x10^-6 Pa (20°C); <2.4x10^-6 Pa (25°C); <4.9x10^-5 Pa (50°C)

Executive summary:

The vapour pressure was determined according to OECD 104. The method is based on the estimation of the mass of test item flowing out per unit of time of a Knudsen cell in the form of vapour, through a micro-orifice under ultra-vacuum conditions. The test item is filled into the test cell and placed in a furnace in the vacuum chamber from which the sample evaporates while heating with asurrounding heater. The mass of effused vapour is obtained by determining the loss of mass of the cell. The vapour pressure is calculated by applying the Hertz-Knudsen relation with correction factors that depend on parameters of the apparatus.

The recommended range of the vapour pressure for this method is 10^-5to 10^-2 hPa and for the temperature between approximately 0 and 120 °C. As the test item started melting above 80°C, the vapour pressure was measured in the temperature range of 50 °C to 80, °C. All measured values were below the detection limit of 1 mPa, wherefore the values for 20, 25 and 50 °C were calculated according to the Antoine equation.

Table2: Calculated vapour pressure at 20, 25 and 50 °C

T / °C	p / hPa	p / Pa
20	< 1.3×10^-8	< 1.3×10^-6
25	< 2.4×10^-8	< 2.4×10^-6
50	< 4.9× 10^-7	< 4.9× 10^-5

This is a conservative estimation of the vapour pressure of the test item for the listed temperatures.

This information is used in a read-across approach in the assessment of the target substance.

For justification of read-across please refer to the attached read-across report (see IUCLID section 13).

 

Description of key information

The vapour pressure was determined according to OECD 104 via vapour pressure balance. As all measured values were below the detection limit of the method (<1mPa), the following upper limit vapour pressure for the test item were calculated according to the Antoine equation.

Table: Calculated vapour pressure at 20, 25 and 50 °C

T / °C	p / hPa	p / Pa
20	< 1.3×10^-8	< 1.3×10^-6
25	< 2.4×10^-8	< 2.4×10^-6
50	< 4.9× 10^-7	< 4.9× 10^-5

This is a conservative estimation of the vapour pressure of the test item for the listed temperatures.

This information is used in a read-across approach in the assessment of the target substance.

For justification of read-across please refer to the attached read-across report (see IUCLID section 13).

 

Key value for chemical safety assessment

Vapour pressure:

0 Pa

at the temperature of:

20 °C