Benzyl benzoate

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:

1983

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

study well documented, meets generally accepted scientific principles, acceptable for assessment

Principles of method if other than guideline:

The method is based on the measurement of the substance concentration in the saturated vapor phase (headspace) which stays in equilibrium with the condensed phase. During the procedure the total amount of substance being present in a defined volume of vapor is collected on an adsorbent and quantified either by gravimetry or, after desorption from the carrier, by chromatography.

A solution of about 100 mg of the substance in 2 ml of pentane is distributed in a 1 L-headspace vesselin such a way that the wall and floor are well wetted. After evaporation of the solvent the vessel is closed by putting on the hood and the
Carbon filter. The apparatus is set in a water bath at 25 °C and allowed to equilibrate for 2 hours. The two Porapak filter inside the headspace vessel are then connected in series at a height of approx. 2 cm above the bottom of the vessel and the headspace
withdrawal using a 100 ml suction device (measured volume 78 ml) at a suction speed of 5 ml / min engaged. After the suction process has ended, additional 5 min are waited to complete pressure equilibration.
To ensure that the substance has been held beack in the front filter quantitatively the downstream filter is desorbed with 70 μl of hexane and the desorbate is checked for the absence of the substance by gas chromatography on a 2 m long column (Carbowax 20M). The front filter containing the amount of substance quantitatively is now slowly (2-3min) desorbed with 70 μl of hexane into a weighed mixing vessel and the volume of the desorbate is determined gravimetrically.
Before characterizing the desorbate by gas chromatography the sample is homgenized by at least 10 times aspiration and expulsion with a syringe.
After having 2 to 3 very well comparable chromatograms (i.e. the sample is homogeneous) a standard solution containing the substance is made in such a way that its peak area or Peak height may derive not more than +/- 20% of the specified value of the sample. Finally, the complete desorption of the substance from the filter by desorbing it again with 70µL Hexane and by gas chromatographic analysis of the post-extract checked.

Samples are prepared in triplicate and 2 to 3 gas chromatograms are recorded.
Amount of substance is determined by comparing the mean peak heights measured with those of an external standard of known concentration.

GLP compliance:

not specified

Type of method:

gas saturation method

Key result

Test no.:

#1

Temp.:

25 °C

Vapour pressure:

0.003 Pa

Remarks on result:

other: headspace method

Test no.:

#2

Temp.:

25 °C

Vapour pressure:

0.004 Pa

Remarks on result:

other: Knudsen-method

Test no.:

#1

Temp.:

ca. 25 °C

Vapour pressure:

ca. 0 Torr

Conclusions:

The vapour pressure of benzyl benzoate determined by headspace gas saturation method is 0.00305 Pa at 25 °C.

Executive summary:

The vapour pressure of benzyl benzoate determined by headspace gas saturation method is 0.00305 Pa (equivalent to 0.000229 Torr (mmHg))

at 25 °C. The article references the vapour pressure determined by a Knudsen cell with 0.00404 Pa at 25 °C.

Reference 2

Endpoint:

vapour pressure

Type of information:

calculation (if not (Q)SAR)

Adequacy of study:

supporting study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

accepted calculation method

Reason / purpose for cross-reference:

other: input value used for calculation

Reason / purpose for cross-reference:

other: input value for calculation

Guideline:

other: ECHA Guidance Document R.16

Version / remarks:

Version 3.0, February 2016

GLP compliance:

no

Type of method:

other: calculation

Test no.:

#1

Temp.:

20 °C

Vapour pressure:

0.02 Pa

Remarks on result:

other: Temperature of water solubility used for estimation.

By using the measured water solubility of 15.3 mg/L, the molecular weight of 212.25 g/mol and the estimated Henry's Law Constant of 0 2.84E-01 Pa*m³/mol, the vapour pressure can be calculated as 0.0205 Pa.

Conclusions:

The vapour pressure of benzyl benzoate was calculated using water solubility, HLC, and molecular weight to 0.0205 Pa.

Executive summary:

The vapour pressure of benzyl benzoate was calculated using the experimentally determined water solubility of 15.3 mg/L at 20 °C, a HLC of 0.284 Pa*m3/mol (estimated by QSAR), and molecular weight of 212.25 g /mol to 0.0205 Pa at 20 °C (setting the estimation at the same temperature as the water solubility data used.

Description of key information

The vapour pressure of benzyl benzoate determined in a study by Etzweiler et al. is 0.0305 Pa at 25 °C. The article references the vapour pressure determined by a Knudsen cell with 0.0404 Pa at 25 °C.

Key value for chemical safety assessment

Vapour pressure:

0.03 Pa

at the temperature of:

25 °C