Mentha arvensis, ext.

Vapour pressure

Link to relevant study record(s)

Reference

Endpoint:

vapour pressure

Type of information:

(Q)SAR

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

results derived from a valid (Q)SAR model and falling into its applicability domain, with adequate and reliable documentation / justification

Justification for type of information:

QSAR prediction: migrated from IUCLID 5.6

Reason / purpose for cross-reference:

reference to same study

Principles of method if other than guideline:

This parameter varies as the composition of the mixture changes during evaporation. For Type 1 NCSs with known constituents the “initial” vapour pressure can be calculated as the sum of the partial pressure of the known constituents. Also a range of the vapour pressure can be given. Therefore, the first approach will be a calculation of the vapour pressure based on constituents. Figure (attached as picture) shows that the measured values are very similar to the estimated values for various citrus oil constituents. Only for constituents with low measured vapour pressure, the estimation method overestimates the vapour pressure. However, it is considered that these extreme non-volatile constituents (<1 Pa) are not relevant for the volatility of the NCS. It is recommended in the NCS protocol to calculate the initial vapour pressure based on the vapour pressures of the individual constituents. From the comparison between estimated and measured data in the figure, it can be concluded that the epiwin calculation method can be considered as reliable. Therefore, the epiwin estimation method is considered as relevant to estimate vapour pressures for this group of constituents. For the initial vapour pressure, the estimated values are used in the calculation. The “initial” vapour pressure is calculated as the sum of the partial pressure of the constituents (based on molecular fraction).

GLP compliance:

no

Type of method:

other: Calculation by estimation

Temp.:

25 °C

Vapour pressure:

50.8 Pa

Remarks on result:

other: Initial vapour pressure

Substance	CAS	Estimated vapour pressure (Pa at 25 degrees Celsius)
L-menthol	2216-51-5	1.02
Menthone	89-80-5	49.4
L-limonene	5989-54-8	193
alpha pinene	7785-70-8	536
betapinene	127-91-3	334
Iso-menthone	491-07-6	49.4
neo-menthol	2216-52-6	1.02
Menthyl Acetate	16409-45-3	12.2
Piperitone	89-81-6	13.8
Pulegone	89-82-7	21.6
Iso-Pulegol	89-79-2	0.662
Germacrene-D	37839-63-7	3.04
Neo-iso pulegol	89-79-2	0.662
1,8-cineole	470-82-6	208
octan-3-ol	589-98-0	13.3
sabinene	3387-41-5	981
Myrcene	123-35-3	320
Neo-iso menthol	89-78-1	1.02
Beta-caryophyllene	87-44-5	4.16

The sum of the vapour pressures multiplied by the fractions in the mixture is 50.2 Pa. To correct for the 1.2% unknown constituents (assuming the average vapour pressure for the unknown constituents is similar to tha average vapour pressure of the known constituents), this number is multiplied by 1 / 0.988.

The vapour pressure of the constituents ranges from 0.662 to 981 Pa.

Conclusions:

The initial vapour pressure of cornmint oil is 50.8 Pa at 25 degrees Celsius.

Executive summary:

The initial vapour pressure of cornmint oil was estimated by calculation. Vapour pressures for the known constiuents were estimated using the QSAR MPBPWIN v 1.43. The sum of the vapour pressures multiplied by the fraction of the substance in the NCS was taken as an inial estimate for the vapour pressure of the mixture. The number obtained was then corrected for the unknown constituents (assuming the average vapour pressure for the unknown constituents is similar to the average vapour pressure of the known constituents).

The initial vapour pressure of cornmint oil was found to be 50.8 Pa at 25 degrees Celsius. The vapour pressure of the constituents ranges from 0.662 to 981 Pa.

Description of key information

50.8 Pa at 25 degrees Celsius

Key value for chemical safety assessment

Vapour pressure:

50.8 Pa

at the temperature of:

25 °C

Additional information

The initial vapour pressure of cornmint oil was estimated by calculation. Vapour pressures for the known constiuents were estimated using the QSAR MPBPWIN v 1.43. The sum of the vapour pressures multiplied by the fraction of the substance in the NCS was taken as an inial estimate for the vapour pressure of the mixture. The number obtained was then corrected for the unknown constituents (assuming the average vapour pressure for the unknown constituents is similar to the average vapour pressure of the known constituents).

The initial vapour pressure of cornmint oil was found to be 50.8 Pa at 25 degrees Celsius. The vapour pressure of the constituents ranges from 0.662 to 981 Pa.