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Vapour pressure

Link to relevant study record(s)

Reference

Endpoint:

vapour pressure

Type of information:

experimental study

Adequacy of study:

key study

Study period:

07 AUG 2020 - 20 OCT 2020

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 104 (Vapour Pressure Curve)

Version / remarks:

23 March, 2006

Qualifier:

according to guideline

Guideline:

other: “Testing Guidelines for Studies of Chemicals”, Section 2.5, “Vapour Pressure Test”

Version / remarks:

Notification No. 2019-23, Ministry of Environment, Republic of Korea(13 June, 2019)

GLP compliance:

no

Type of method:

effusion method: isothermal thermogravimetry

Test no.:

#1

Temp.:

25 °C

Vapour pressure:

0 Pa

Regressing log p_T vs. log v_T

To obtain the specific constants 'C' and 'D' in the regression equation of log pT = C + D ·log vT, naphthalene was analyzed at 40.33, 49.45, 60.23, 70.19 and 80.33 °C(313.48, 322.60, 333.38, 343.34 and 353.48 K), and the regression equation was obtained using the relationship with the vapor pressure according to the literature information. The coefficient of determination(R2) was > 0.99(0.9989). The specific constants 'C' and 'D' were calculated for once every six months.

log p_T = 4.6374 + 1.1213 · log v_T

 

The Result of Vapor Pressure

The evaporation rates v_T of the test material at 514.55, 524.05 and 530.08 K(241.40, 250.90 and 256.93 °C) were 0.000283, 0.000389 and 0.000601 gcm^-2 h^-1, respectively. Thus, the vapor pressure p_T of the test substance at each temperature was calculated to be 4.54, 6.52 and 10.7 Pa, respectively.

 

Regressing log p_T vs 1/T

The following regression equation was used to obtain the constants 'A' and 'B' in the regression equation of log pT = A + B · 1 / T using the vapor pressure test results. The coefficient of determination(R²) was > 0.95(0.9581).

log p_T = 14.771 – 7284.2 * 1/T

 

The Vapor Pressure Estimated Value at 25.0 °C

The vapor pressure at 298.15 K(25.0 °C) of the test substance obtained by extrapolation according to the relationship between the vapor pressure pT and the temperature T of the test substance was calculated to be 2.34E^-10 Pa.

Conclusions:

The vapour pressure of the test item was estimated to be 2.34E-10 Pa at 298.15 K (25.0 °C).

Executive summary:

The vapour pressure test was performed according to the OECD guideline 104 in a non-GLP study. As a result of the vapour pressure test according to the effusion method using TGA, the vapour pressures of the test substance was measured to be 4.54, 6.52 and 10.7 Pa at 514.55, 524.05 and 530.08 K and atmospheric pressure (101.3 kPa), respectively. And according to the relation of the vapor pressure pT and the temperature T, the vapor pressure was estimated to be 2.34E^-10 Pa at 298.15 K (25.0 °C).

Description of key information

The vapour pressure test was performed according to the OECD guideline 104 in a non-GLP study. As a result of the vapour pressure test according to the effusion method using TGA, the vapour pressures of the test substance was measured to be 4.54, 6.52 and 10.7 Pa at 514.55, 524.05 and 530.08 K and atmospheric pressure (101.3 kPa), respectively. And according to the relation of the vapor pressure pT and the temperature T, the vapor pressure was estimated to be 2.34E^-10 Pa at 298.15 K (25.0 °C).

Key value for chemical safety assessment

Vapour pressure:

0 Pa

at the temperature of:

25 °C